/**
 * Dynamic Cordis Plugin service: immutable package definitions, one active run
 * per Plugin, human-approved Client activation, and Host/Client invocation.
 * @module @deepseek-ai/dsh-cordis-host-runner
 */

import { Context } from '@deepseek-ai/cordis'
import type { Fiber } from '@deepseek-ai/cordis'
import z from '@deepseek-ai/schemastery'
import type { Agent } from '@deepseek-ai/dsh-agent'
import { createUserMessage } from '@deepseek-ai/dsh-llm'
import type { JsonValue } from '@deepseek-ai/dsh-session/types'
import { TypertRemoteService, Remote } from '@deepseek-ai/dsh-typert-protocol'
import { isPlugin, normalizeHandler } from './guard.ts'
import { CordisInspectRegistryService } from './inspect-registry.ts'
import { missingServices, startHostHalf } from './lifecycle.ts'
import { DynamicCordisRegistry } from './registry.ts'
import type {
  DynamicCordisDefineReceipt, DynamicCordisDefineRequest, DynamicCordisDefinition,
  DynamicCordisPackageInspection, DynamicCordisPendingRequest, DynamicCordisPlugin,
  DynamicCordisPluginInspection,
  DynamicCordisReference, DynamicCordisRun,
} from './registry.ts'
import { createSandbox, evaluateHostCode, precheckCode } from './sandbox.ts'
import type {
  ApprovalRequestId, CordisDynamicPackageId, CordisDynamicPluginId, CordisDynamicPluginRunId, CordisErrorDetails,
  CordisDynamicRunMode, CordisInspectProviderManifest, CordisInspectQueryResolution,
  CordisInspectRequestId, CordisInspectResolveAck, DynamicCordisClientSource, DynamicCordisHostHalfResult,
  DynamicCordisInventoryRow, DynamicCordisInvokeResult, DynamicCordisRenderFailure, DynamicCordisResolveAck,
  DynamicCordisRunAttempt, DynamicCordisRunResolution, DynamicCordisRunResponse, DynamicCordisStopResponse,
  DynamicCordisUndefineReceipt, RequestRunOutcome,
} from './types.ts'

export type * from './types.ts'
export type {
  DynamicCordisDefineReceipt, DynamicCordisDefineRequest, DynamicCordisDefinition, DynamicCordisHandler,
  DynamicCordisPackageInspection, DynamicCordisPlugin, DynamicCordisPluginInspection,
  DynamicCordisReference, DynamicCordisRun,
} from './registry.ts'
export { CordisInspectRegistryService } from './inspect-registry.ts'
export type { HostCordisInspectProviderRegistration } from './inspect-registry.ts'
export { HOST_BUILTIN_INSPECTION } from './sandbox.ts'

/**
 * Brand a Host-minted Plugin ID.
 * @param id - opaque identifier minted by the Host registry.
 * @returns the branded Plugin identifier.
 */
export function CordisDynamicPluginId(id: string): CordisDynamicPluginId {
  return id as CordisDynamicPluginId
}

/**
 * Brand a Host-minted Package ID.
 * @param id - opaque identifier minted by the Host registry.
 * @returns the branded Package identifier.
 */
export function CordisDynamicPackageId(id: string): CordisDynamicPackageId {
  return id as CordisDynamicPackageId
}

/**
 * Brand a Host-minted Plugin Run ID.
 * @param id - opaque identifier minted by the Host registry.
 * @returns the branded Plugin Run identifier.
 */
export function CordisDynamicPluginRunId(id: string): CordisDynamicPluginRunId {
  return id as CordisDynamicPluginRunId
}

/**
 * Brand a Host-minted approval request ID.
 * @param id - opaque identifier minted by the Host registry.
 * @returns the branded approval request identifier.
 */
export function ApprovalRequestId(id: string): ApprovalRequestId {
  return id as ApprovalRequestId
}

declare module '@deepseek-ai/cordis' {
  interface Context {
    /** Process-local dynamic Plugin registry and lifecycle service. */
    dynamicCordisRunner: DynamicCordisRunnerService
  }
}

/** Runner configuration. */
export interface Config {
  /** Maximum synchronous VM evaluation time in milliseconds. */
  vmTimeoutMs?: number
}

type ResolvedConfig = Required<Config>

/** Host-only snapshot consumed by inspect and tool result rendering. */
export interface DynamicCordisSnapshotRow {
  pluginId: CordisDynamicPluginId
  currentPackageId?: CordisDynamicPackageId
  nextPackageId?: CordisDynamicPackageId
  packages: Array<{
    packageId: CordisDynamicPackageId
    name: string
    purpose: string
    hasHostHalf: boolean
    hasClientHalf: boolean
  }>
  activeRun?: {
    pluginRunId: CordisDynamicPluginRunId
    packageId: CordisDynamicPackageId
    fiber?: Fiber
    handlers: string[]
    renderFailure?: DynamicCordisRenderFailure
  }
  latestRun?: DynamicCordisRunAttempt
}

interface ActivationPlan {
  plugin: DynamicCordisPlugin
  definition: DynamicCordisDefinition
  mode: CordisDynamicRunMode
}

/** Dynamic Plugin registry and Host-half lifecycle. */
export class DynamicCordisRunnerService extends TypertRemoteService {
  static inject = ['tools']

  static Config: z<Config> = z.object({
    vmTimeoutMs: z.number().min(1).default(5000),
  })

  private readonly rootCtx: Context
  private readonly registry = new DynamicCordisRegistry()
  private readonly inspectRegistry: CordisInspectRegistryService
  private readonly starting = new Map<CordisDynamicPluginId, Promise<DynamicCordisHostHalfResult>>()
  private readonly resolved: ResolvedConfig
  private group: Fiber | undefined

  /** Create the service under the Host composition. */
  constructor(ctx: Context, config: Config) {
    super(ctx, 'dynamicCordisRunner')
    this.rootCtx = ctx
    this.resolved = config as ResolvedConfig
    this.inspectRegistry = new CordisInspectRegistryService(ctx)
  }

  /**
   * Define a new Plugin's first Package or append a Package to an existing Plugin.
   * @param request - Session ownership, Plugin selection, metadata, and source code.
   * @returns Host-minted Plugin and Package identities with declared-half metadata.
   */
  define(request: DynamicCordisDefineRequest): DynamicCordisDefineReceipt {
    const name = request.name.trim()
    const purpose = request.purpose.trim()
    if (name.length === 0) throw new Error('cordis_define needs a non-empty `name`')
    if (purpose.length === 0) throw new Error('cordis_define needs a non-empty `purpose`')
    if (request.code.host === undefined && request.code.client === undefined) {
      throw new Error('cordis_define needs `code.host`, `code.client`, or both')
    }
    if (request.code.host !== undefined) precheckCode(request.code.host, 'code.host')
    if (request.code.client !== undefined) precheckCode(request.code.client, 'code.client')

    let plugin: DynamicCordisPlugin
    if (request.plugin.kind === 'new') {
      const prefix = request.plugin.idPrefix.trim()
      if (!/^[a-z]{3,6}$/.test(prefix)) {
        throw new Error('cordis_define `plugin.idPrefix` must contain 3–6 lowercase English letters')
      }
      const pluginId = CordisDynamicPluginId(this.registry.mintPluginId(prefix))
      plugin = {
        pluginId,
        sessionId: request.sessionId,
        packages: new Map(),
        approvedClientPackages: new Set(),
        clientVersionUpdatesApproved: false,
      }
      this.registry.add(plugin)
    } else {
      const found = this.registry.get(request.plugin.pluginId)
      if (found === undefined || found.sessionId !== request.sessionId) {
        throw new Error(missingPluginMessage(request.plugin.pluginId))
      }
      plugin = found
    }

    const packageId = CordisDynamicPackageId(this.registry.mintPackageId())
    const definition: DynamicCordisDefinition = {
      packageId,
      name,
      purpose,
      ...request.code.host === undefined ? {} : { hostCode: request.code.host },
      ...request.code.client === undefined ? {} : { clientCode: request.code.client },
    }
    plugin.packages.set(packageId, definition)
    return {
      pluginId: plugin.pluginId,
      packageId,
      name,
      purpose,
      hasHostHalf: definition.hostCode !== undefined,
      hasClientHalf: definition.clientCode !== undefined,
    }
  }

  /**
   * Remove a Plugin, its active run, and all immutable Packages.
   * @param agent - Agent whose Session must own the Plugin.
   * @param pluginId - Stable Plugin identity to remove.
   * @returns Whether removal succeeded and whether it stopped an active run.
   */
  async undefine(agent: Agent, pluginId: CordisDynamicPluginId): Promise<DynamicCordisUndefineReceipt> {
    const plugin = this.owned(agent, pluginId)
    if (plugin === undefined) return { ok: false, reason: 'plugin-missing', message: missingPluginMessage(pluginId) }
    const wasRunning = plugin.run !== undefined
    this.cancelPending(pluginId, `dynamic plugin "${pluginId}" was removed before approval`)
    if (plugin.run !== undefined) await this.retract(plugin)
    this.registry.delete(pluginId)
    return { ok: true, wasRunning }
  }

  /**
   * Remove a Plugin from the user panel and queue the resulting state change for the model's next step.
   * @param agent - Agent whose Session owns the Plugin and receives the context.
   * @param pluginId - Stable Plugin identity to remove.
   * @returns Whether removal succeeded and whether it stopped an active run.
   */
  @Remote('undefineFromPanel')
  async undefineFromPanel(agent: Agent, pluginId: CordisDynamicPluginId): Promise<DynamicCordisUndefineReceipt> {
    const result = await this.undefine(agent, pluginId)
    if (result.ok) {
      this.injectUserContext(
        agent,
        `The user removed Cordis Plugin ${pluginId} and all of its Packages. The Plugin no longer exists.`,
      )
    }
    return result
  }

  /**
   * Start or update one Package for a model tool call. An unauthorized Client
   * Package waits for approval; Plugin-wide authorization covers later versions.
   * @param agent - Agent whose Session must own the Plugin.
   * @param pluginId - Stable Plugin identity to activate.
   * @param packageId - Immutable Package version to activate.
   * @param mode - Whether to run the current version or switch versions.
   * @param signal - Tool-call cancellation signal while the activation request is being created.
   * @returns The successful activation identity or an actionable refusal.
   */
  async run(
    agent: Agent,
    pluginId: CordisDynamicPluginId,
    packageId: CordisDynamicPackageId,
    mode: CordisDynamicRunMode,
    signal?: AbortSignal,
  ): Promise<DynamicCordisRunResponse> {
    const plan = this.resolvePlan(agent, pluginId, packageId, mode)
    if (!plan.ok) return plan.response
    if (signal?.aborted === true) {
      return {
        ok: false,
        reason: 'cancelled',
        message: `the run request for dynamic plugin "${pluginId}" was cancelled before activation`,
      }
    }
    if (this.registry.pendingRequestFor(pluginId) !== undefined) {
      return { ok: false, reason: 'transition-in-flight', message: `dynamic plugin "${pluginId}" already has a pending run request` }
    }
    const attempt = this.createAttempt(plan)
    plan.plugin.nextPackageId = packageId
    plan.plugin.latestRun = attempt
    if (plan.definition.clientCode === undefined) {
      const started = await this.activate(plan, undefined, false, attempt)
      if (started.ok) return this.runResponse(plan.plugin, started)
      this.failAttempt(plan.plugin, attempt, 'host-load', started)
      return { ...started, reason: 'host-half-failed' }
    }

    const requestId = ApprovalRequestId(this.registry.mintApprovalRequestId())
    const requiresApproval = !plan.plugin.clientVersionUpdatesApproved
      && !plan.plugin.approvedClientPackages.has(packageId)
    attempt.approvalRequestId = requestId
    attempt.requiresApproval = requiresApproval
    attempt.status = requiresApproval ? 'awaiting-approval' : 'starting-host'
    this.registry.armRequest(requestId, {
      agentId: agent.id,
      pluginId,
      packageId,
      pluginRunId: attempt.pluginRunId,
      mode,
      requiresApproval,
    })
    this.ctx.emit('cordis/request-run', {
      requestId,
      agentId: agent.id,
      pluginId,
      packageId,
      mode,
      name: plan.definition.name,
      purpose: plan.definition.purpose,
      requiresApproval,
    })
    return {
      ok: true,
      status: requiresApproval ? 'awaiting-approval' : 'starting',
      pluginId,
      packageId,
      pluginRunId: attempt.pluginRunId,
      mode,
      waitingFor: [],
      ...plan.plugin.currentPackageId === undefined ? {} : { currentPackageId: plan.plugin.currentPackageId },
      nextPackageId: packageId,
    }
  }

  /**
   * Start Host code for an approved request or a direct panel gesture.
   * @param agent - Agent whose Session must own the Plugin.
   * @param pluginId - Stable Plugin identity to activate.
   * @param packageId - Immutable Package version to activate.
   * @param mode - Whether to run the current version or switch versions.
   * @param requestId - Model-driven request identity, or null for a direct user gesture.
   * @param approveFutureVersions - Whether this approval covers later Packages of the same Plugin.
   * @returns The exact Host activation or a failure message.
   */
  @Remote('runHostHalf')
  async runHostHalf(
    agent: Agent,
    pluginId: CordisDynamicPluginId,
    packageId: CordisDynamicPackageId,
    mode: CordisDynamicRunMode,
    requestId: ApprovalRequestId | null,
    approveFutureVersions: boolean,
  ): Promise<DynamicCordisHostHalfResult> {
    const plan = this.resolvePlan(agent, pluginId, packageId, mode, requestId === null)
    if (!plan.ok) return { ok: false, message: plan.response.message }
    let attempt: DynamicCordisRunAttempt
    if (requestId !== null) {
      const pending = this.registry.peekRequest(requestId)
      if (pending === undefined || pending.pluginId !== pluginId || pending.packageId !== packageId || pending.mode !== mode) {
        return { ok: false, message: `run request "${requestId}" does not authorize ${pluginId}/${packageId}` }
      }
      const latest = plan.plugin.latestRun
      const expectedStatus = pending.requiresApproval ? 'awaiting-approval' : 'starting-host'
      if (latest === undefined || latest.pluginRunId !== pending.pluginRunId
        || (latest.status !== expectedStatus && (!pending.requiresApproval && latest.status !== 'client-pending'))) {
        return { ok: false, message: `run request "${requestId}" no longer identifies the latest run of ${pluginId}` }
      }
      attempt = latest
      if (pending.requiresApproval) {
        plan.plugin.approvedClientPackages.add(packageId)
        if (approveFutureVersions) plan.plugin.clientVersionUpdatesApproved = true
      }
    } else {
      const pending = this.registry.pendingRequestFor(pluginId)
      if (pending !== undefined) return { ok: false, message: `dynamic plugin "${pluginId}" has pending run request ${pending}` }
      const attached = plan.plugin.run?.packageId === packageId
        && plan.plugin.latestRun?.pluginRunId === plan.plugin.run.pluginRunId
        ? plan.plugin.latestRun
        : undefined
      attempt = attached ?? this.createAttempt(plan)
      if (attached === undefined) {
        plan.plugin.nextPackageId = packageId
        plan.plugin.latestRun = attempt
      }
      if (plan.definition.clientCode !== undefined) plan.plugin.approvedClientPackages.add(packageId)
    }
    const attaching = attempt.pluginRunId === plan.plugin.run?.pluginRunId
    if (!attaching) {
      attempt.status = 'starting-host'
      if (attempt.host.status !== 'absent') attempt.host = { status: 'pending', waitingFor: [] }
    }
    const started = await this.activate(plan, requestId ?? undefined, attaching, attempt)
    if (!started.ok) this.failAttempt(plan.plugin, attempt, 'host-load', started)
    return started
  }

  /**
   * Fetch Client code for the exact active run.
   * @param agent - Agent whose Session must own the Plugin.
   * @param pluginId - Stable Plugin identity to read.
   * @param pluginRunId - Exact active run authorized to receive source.
   * @returns Client source and its Plugin, Package, and run identities.
   */
  @Remote('getClientCode')
  getClientCode(
    agent: Agent,
    pluginId: CordisDynamicPluginId,
    pluginRunId: CordisDynamicPluginRunId,
  ): DynamicCordisClientSource {
    const plugin = this.owned(agent, pluginId)
    if (plugin === undefined) throw new Error(missingPluginMessage(pluginId))
    const run = plugin.run
    if (run === undefined || run.pluginRunId !== pluginRunId) {
      throw new Error(`dynamic plugin "${pluginId}" is not running activation "${pluginRunId}"`)
    }
    const definition = plugin.packages.get(run.packageId)
    if (definition?.clientCode === undefined) throw new Error(`package "${run.packageId}" has no Client half`)
    return {
      code: definition.clientCode,
      name: definition.name,
      pluginId,
      packageId: run.packageId,
      pluginRunId,
    }
  }

  /**
   * Resolve one model-driven Client activation request.
   * @param requestId - Request identity to settle once.
   * @param resolution - Browser refusal or exact Client activation result.
   * @returns Whether the still-pending request accepted this resolution.
   */
  @Remote('resolveRequestRun')
  async resolveRequestRun(
    requestId: ApprovalRequestId,
    resolution: DynamicCordisRunResolution,
  ): Promise<DynamicCordisResolveAck> {
    const pending = this.registry.peekRequest(requestId)
    if (pending === undefined) return { accepted: false }
    const plugin = this.registry.get(pending.pluginId)
    if (resolution.ok && plugin?.run?.pluginRunId !== resolution.pluginRunId) return { accepted: false }
    if (!resolution.ok && resolution.pluginRunId !== undefined
      && plugin?.run?.pluginRunId !== resolution.pluginRunId) return { accepted: false }
    this.registry.claimRequest(requestId)
    const settled = await this.settleActivation(plugin, resolution, requestId)
    this.announceResolved(requestId, resolution, pending.requiresApproval ? undefined : 'completed')
    this.steerRunOutcome(pending, settled)
    return { accepted: true }
  }

  /**
   * Settle a direct panel run after this page loaded or failed its Client half.
   * @param agent - Agent whose Session must own the Plugin.
   * @param pluginId - Stable Plugin identity being settled.
   * @param resolution - Exact Client activation result from the acting page.
   * @returns The committed activation or its failure.
   */
  @Remote('settleUserRun')
  async settleUserRun(
    agent: Agent,
    pluginId: CordisDynamicPluginId,
    resolution: DynamicCordisRunResolution,
  ): Promise<DynamicCordisRunResponse> {
    const plugin = this.owned(agent, pluginId)
    if (plugin === undefined) return { ok: false, reason: 'plugin-missing', message: missingPluginMessage(pluginId) }
    const settled = await this.settleActivation(plugin, resolution)
    this.injectUserRunOutcome(agent, pluginId, settled)
    return settled
  }

  /**
   * Stop the active run while retaining every Package version.
   * @param agent - Agent whose Session must own the Plugin.
   * @param pluginId - Stable Plugin identity to stop.
   * @returns Success or the reason no run was stopped.
   */
  async stop(agent: Agent, pluginId: CordisDynamicPluginId): Promise<DynamicCordisStopResponse> {
    const plugin = this.owned(agent, pluginId)
    if (plugin === undefined) return { ok: false, reason: 'plugin-missing', message: missingPluginMessage(pluginId) }
    const pending = this.registry.pendingRequestFor(pluginId)
    if (plugin.run === undefined && pending === undefined) {
      return { ok: false, reason: 'not-running', message: `dynamic plugin "${pluginId}" is not running` }
    }
    if (pending !== undefined) this.cancelPending(pluginId, `dynamic plugin "${pluginId}" was stopped before approval`)
    if (plugin.run !== undefined) await this.retract(plugin)
    if (plugin.latestRun !== undefined) {
      plugin.latestRun.status = 'stopped'
      if (plugin.latestRun.host.status !== 'absent') plugin.latestRun.host = { status: 'stopped', waitingFor: [] }
      if (plugin.latestRun.client.status !== 'absent') plugin.latestRun.client = { status: 'stopped', waitingFor: [] }
    }
    return { ok: true }
  }

  /**
   * Stop a Plugin from the user panel and queue the resulting state change for the model's next step.
   * @param agent - Agent whose Session owns the Plugin and receives the context.
   * @param pluginId - Stable Plugin identity to stop.
   * @returns Success or the reason no run was stopped.
   */
  @Remote('stopFromPanel')
  async stopFromPanel(agent: Agent, pluginId: CordisDynamicPluginId): Promise<DynamicCordisStopResponse> {
    const result = await this.stop(agent, pluginId)
    if (!result.ok) return result
    const plugin = this.owned(agent, pluginId)
    this.injectUserContext(
      agent,
      `The user stopped Cordis Plugin ${pluginId}. Its Packages remain defined; currentPackageId is `
        + `${plugin?.currentPackageId ?? 'none'}.`,
    )
    return result
  }

  /**
   * Replace the Host mirror of the Client inspect provider directory.
   * @param providers - complete Client provider manifest.
   * @returns null after accepting the manifest.
   */
  @Remote('syncInspectManifest')
  syncInspectManifest(providers: readonly CordisInspectProviderManifest[]): null {
    this.inspectRegistry.syncClientManifest(providers)
    return null
  }

  /**
   * Claim one pending Client inspect query with its live result.
   * @param agent - Session that owns the query.
   * @param requestId - exact pending query identity.
   * @param resolution - provider result or structured refusal.
   * @returns whether this answer won the query.
   */
  @Remote('resolveInspectQuery')
  resolveInspectQuery(
    agent: Agent,
    requestId: CordisInspectRequestId,
    resolution: CordisInspectQueryResolution,
  ): CordisInspectResolveAck {
    return this.inspectRegistry.resolveClientQuery(agent, requestId, resolution)
  }

  /**
   * Frame-wide inventory, grouped as one row per stable Plugin.
   * @returns Source-free metadata for every process-local Plugin.
   */
  /* jscpd:ignore-start */
  @Remote('inventory')
  inventory(): DynamicCordisInventoryRow[] {
    return this.registry.all().map(plugin => ({
      pluginId: plugin.pluginId,
      agentId: plugin.sessionId,
      packages: [...plugin.packages.values()].map(definition => ({
        packageId: definition.packageId,
        name: definition.name,
        purpose: definition.purpose,
        hasHostHalf: definition.hostCode !== undefined,
        hasClientHalf: definition.clientCode !== undefined,
      })),
      ...plugin.currentPackageId === undefined ? {} : { currentPackageId: plugin.currentPackageId },
      ...plugin.nextPackageId === undefined ? {} : { nextPackageId: plugin.nextPackageId },
      ...plugin.run === undefined ? {} : {
        activeRun: { pluginRunId: plugin.run.pluginRunId, packageId: plugin.run.packageId },
      },
      ...plugin.latestRun === undefined ? {} : { latestRun: cloneAttempt(plugin.latestRun) },
    }))
  }
  /* jscpd:ignore-end */

  /**
   * Read one Session's Host-rich state for inspection and result rendering.
   * @param agent - Agent whose Session selects visible Plugins.
   * @returns Plugin versions, active runs, Host fibers, and render failures.
   */
  snapshot(agent: Agent): DynamicCordisSnapshotRow[] {
    return this.registry.ofSession(agent.id).map(plugin => ({
      pluginId: plugin.pluginId,
      ...plugin.currentPackageId === undefined ? {} : { currentPackageId: plugin.currentPackageId },
      ...plugin.nextPackageId === undefined ? {} : { nextPackageId: plugin.nextPackageId },
      packages: [...plugin.packages.values()].map(definition => ({
        packageId: definition.packageId,
        name: definition.name,
        purpose: definition.purpose,
        hasHostHalf: definition.hostCode !== undefined,
        hasClientHalf: definition.clientCode !== undefined,
      })),
      ...plugin.run === undefined ? {} : {
        activeRun: {
          pluginRunId: plugin.run.pluginRunId,
          packageId: plugin.run.packageId,
          ...plugin.run.fiber === undefined ? {} : { fiber: plugin.run.fiber },
          handlers: [...plugin.run.handlers.keys()],
          ...plugin.run.renderFailure === undefined ? {} : { renderFailure: plugin.run.renderFailure },
        },
      },
      ...plugin.latestRun === undefined ? {} : { latestRun: cloneAttempt(plugin.latestRun) },
    }))
  }

  /**
   * Read source-free context for an explicit `@pluginId` user gesture.
   * @param agent - Agent whose Session must own the Plugin.
   * @param pluginId - Stable Plugin identity referenced by the user.
   * @returns The preferred modification base, or undefined when unavailable.
   */
  reference(agent: Agent, pluginId: CordisDynamicPluginId): DynamicCordisReference | undefined {
    const plugin = this.owned(agent, pluginId)
    if (plugin === undefined) return undefined
    const packageId = plugin.nextPackageId
      ?? plugin.currentPackageId
      ?? [...plugin.packages.keys()].at(-1)
    if (packageId === undefined) return undefined
    const definition = plugin.packages.get(packageId)
    if (definition === undefined) return undefined
    return {
      pluginId,
      packageId,
      name: definition.name,
      purpose: definition.purpose,
      ...plugin.currentPackageId === undefined ? {} : { currentPackageId: plugin.currentPackageId },
      ...plugin.nextPackageId === undefined ? {} : { nextPackageId: plugin.nextPackageId },
      ...plugin.run === undefined ? {} : {
        activeRun: { pluginRunId: plugin.run.pluginRunId, packageId: plugin.run.packageId },
      },
      ...plugin.latestRun === undefined ? {} : { latestRun: cloneAttempt(plugin.latestRun) },
    }
  }

  /**
   * List source-free Plugin summaries owned by one Session.
   * @param agent - Agent whose Session selects visible Plugins.
   * @returns one summary per Plugin in creation order.
   */
  listPlugins(agent: Agent): DynamicCordisPluginInspection[] {
    return this.registry.ofSession(agent.id).map(plugin => this.inspectPlugin(agent, plugin.pluginId))
  }

  /**
   * Inspect one Plugin without returning Package source.
   * @param agent - Agent whose Session must own the Plugin.
   * @param pluginId - stable Plugin identity.
   * @returns version pointers, latest run, and all Package summaries.
   */
  inspectPlugin(agent: Agent, pluginId: CordisDynamicPluginId): DynamicCordisPluginInspection {
    const plugin = this.owned(agent, pluginId)
    if (plugin === undefined) throw new Error(missingPluginMessage(pluginId))
    const reference = this.reference(agent, pluginId)
    if (reference === undefined) throw new Error(`dynamic plugin "${pluginId}" has no package`)
    return {
      ...reference,
      packages: [...plugin.packages.values()].map(definition => ({
        packageId: definition.packageId,
        name: definition.name,
        purpose: definition.purpose,
        hasHostHalf: definition.hostCode !== undefined,
        hasClientHalf: definition.clientCode !== undefined,
      })),
    }
  }

  /**
   * Read one exact immutable Package and its Host and Client source.
   * @param agent - Agent whose Session must own the Plugin.
   * @param pluginId - Stable Plugin identity that owns the Package.
   * @param packageId - Exact immutable Package identity to inspect.
   * @returns Package metadata, source, and the Plugin's lifecycle pointers.
   */
  inspectPackage(
    agent: Agent,
    pluginId: CordisDynamicPluginId,
    packageId: CordisDynamicPackageId,
  ): DynamicCordisPackageInspection {
    const plugin = this.owned(agent, pluginId)
    if (plugin === undefined) throw new Error(missingPluginMessage(pluginId))
    const definition = plugin.packages.get(packageId)
    if (definition === undefined) {
      throw new Error(`dynamic package "${packageId}" does not exist on plugin "${pluginId}"`)
    }
    return {
      pluginId,
      packageId,
      name: definition.name,
      purpose: definition.purpose,
      code: {
        ...definition.hostCode === undefined ? {} : { host: definition.hostCode },
        ...definition.clientCode === undefined ? {} : { client: definition.clientCode },
      },
      /* jscpd:ignore-start */
      ...plugin.currentPackageId === undefined ? {} : { currentPackageId: plugin.currentPackageId },
      ...plugin.nextPackageId === undefined ? {} : { nextPackageId: plugin.nextPackageId },
      ...plugin.run === undefined ? {} : {
        activeRun: { pluginRunId: plugin.run.pluginRunId, packageId: plugin.run.packageId },
      },
      ...plugin.latestRun === undefined ? {} : { latestRun: cloneAttempt(plugin.latestRun) },
      /* jscpd:ignore-end */
    }
  }

  /**
   * Record a post-load render failure for the exact active run.
   * @param agent - Agent whose Session must own the Plugin.
   * @param pluginId - Stable Plugin identity that rendered.
   * @param pluginRunId - Exact active run that produced the failure.
   * @param failure - Slot, message, and entry-retirement result.
   * @returns Null after recording or ignoring a stale report.
   */
  @Remote('reportRenderFailure')
  async reportRenderFailure(
    agent: Agent,
    pluginId: CordisDynamicPluginId,
    pluginRunId: CordisDynamicPluginRunId,
    failure: DynamicCordisRenderFailure,
  ): Promise<null> {
    const plugin = this.owned(agent, pluginId)
    if (plugin?.run?.pluginRunId === pluginRunId) {
      const run = plugin.run
      const definition = plugin.packages.get(plugin.run.packageId)
      const shouldSteer = run.renderFailure === undefined
      run.renderFailure = failure
      const attempt = plugin.latestRun
      if (attempt?.pluginRunId === pluginRunId) {
        attempt.error = this.diagnostic(plugin, attempt, 'client-render', failure)
        attempt.client = { status: 'failed', waitingFor: attempt.client.waitingFor, error: failure.message }
        attempt.status = 'failed'
      }
      if (definition !== undefined && shouldSteer) {
        this.steerRenderFailure(agent, plugin, definition, pluginRunId, failure)
      }
    }
    return await Promise.resolve(null)
  }

  /**
   * Report a Client guard rejection that happened after the Package completed activation.
   * @param agent - Agent whose Session must own the Plugin.
   * @param pluginId - Stable Plugin identity whose Client code was rejected.
   * @param pluginRunId - Exact active run that produced the rejection.
   * @param failure - Original guard message and stack.
   * @returns Null after reporting or ignoring a stale/startup failure.
   */
  @Remote('reportClientGuardFailure')
  async reportClientGuardFailure(
    agent: Agent,
    pluginId: CordisDynamicPluginId,
    pluginRunId: CordisDynamicPluginRunId,
    failure: CordisErrorDetails,
  ): Promise<null> {
    const plugin = this.owned(agent, pluginId)
    const run = plugin?.run
    if (plugin !== undefined && run?.pluginRunId === pluginRunId) {
      this.steerGuardFailure(plugin, run, 'Client', failure)
    }
    return await Promise.resolve(null)
  }

  /**
   * Invoke an active Host method while rejecting stale Client runs.
   * @param pluginId - Stable Plugin identity that owns the method.
   * @param pluginRunId - Exact active run authorizing the call.
   * @param method - Registered Host handler name.
   * @param args - JSON argument delivered to the handler.
   * @returns The JSON result or a typed invocation failure.
   */
  @Remote('invoke')
  async invoke(
    pluginId: CordisDynamicPluginId,
    pluginRunId: CordisDynamicPluginRunId,
    method: string,
    args: JsonValue,
  ): Promise<DynamicCordisInvokeResult> {
    const plugin = this.registry.get(pluginId)
    if (plugin === undefined || plugin.run === undefined) {
      return { ok: false, code: 'plugin-not-running', message: `dynamic plugin "${pluginId}" is not running` }
    }
    const run = plugin.run
    if (run.pluginRunId !== pluginRunId) {
      return { ok: false, code: 'stale-run', message: `activation "${pluginRunId}" is no longer active` }
    }
    const handler = run.handlers.get(method)
    if (handler === undefined) {
      return { ok: false, code: 'method-not-found', message: `dynamic plugin "${pluginId}" registered no Host method "${method}"` }
    }
    try {
      return { ok: true, value: await handler(args) as JsonValue }
    } catch (error) {
      const failure = errorDetails(error)
      this.steerHostHandlerFailure(plugin, run, method, failure)
      return { ok: false, code: 'handler-error', ...failure }
    }
  }

  private resolvePlan(
    agent: Agent,
    pluginId: CordisDynamicPluginId,
    packageId: CordisDynamicPackageId,
    mode: CordisDynamicRunMode,
    allowActiveAttach = false,
  ): { ok: true } & ActivationPlan | { ok: false; response: Extract<DynamicCordisRunResponse, { ok: false }> } {
    const plugin = this.owned(agent, pluginId)
    if (plugin === undefined) return { ok: false, response: { ok: false, reason: 'plugin-missing', message: missingPluginMessage(pluginId) } }
    const definition = plugin.packages.get(packageId)
    if (definition === undefined) {
      return { ok: false, response: { ok: false, reason: 'package-missing', message: `plugin "${pluginId}" has no package "${packageId}"` } }
    }
    const current = plugin.currentPackageId
    if (mode === 'update' && (current === undefined || current === packageId)) {
      return {
        ok: false,
        response: {
          ok: false,
          reason: 'invalid-mode',
          message: current === undefined
            ? `plugin "${pluginId}" has no successful version yet; start "${packageId}" with mode "run"`
            : `package "${packageId}" is already current; use mode "run"`,
        },
      }
    }
    if (mode === 'run' && current !== undefined && current !== packageId) {
      return {
        ok: false,
        response: {
          ok: false,
          reason: 'invalid-mode',
          message: `package "${packageId}" differs from current "${current}"; use mode "update"`,
        },
      }
    }
    if (!allowActiveAttach && this.starting.has(pluginId)) {
      return { ok: false, response: { ok: false, reason: 'transition-in-flight', message: `plugin "${pluginId}" is already starting` } }
    }
    return { ok: true, plugin, definition, mode }
  }

  private activate(
    plan: ActivationPlan,
    requestId: ApprovalRequestId | undefined,
    allowActiveAttach: boolean,
    attempt: DynamicCordisRunAttempt,
  ): Promise<DynamicCordisHostHalfResult> {
    const inFlight = this.starting.get(plan.plugin.pluginId)
    if (inFlight !== undefined) return inFlight
    const starting = this.startFresh(plan, requestId, allowActiveAttach, attempt)
    this.starting.set(plan.plugin.pluginId, starting)
    return starting.finally(() => { this.starting.delete(plan.plugin.pluginId) })
  }

  private async startFresh(
    plan: ActivationPlan,
    requestId: ApprovalRequestId | undefined,
    allowActiveAttach: boolean,
    attempt: DynamicCordisRunAttempt,
  ): Promise<DynamicCordisHostHalfResult> {
    const { plugin, definition, mode } = plan
    if (allowActiveAttach
      && plugin.run?.packageId === definition.packageId
      && plugin.run.pluginRunId === attempt.pluginRunId) {
      return {
        ok: true,
        pluginId: plugin.pluginId,
        packageId: definition.packageId,
        pluginRunId: plugin.run.pluginRunId,
        waitingFor: missingFor(this.ctx, plugin.run),
        startedHere: false,
      }
    }
    if (plugin.run !== undefined) await this.retract(plugin)
    if (mode === 'update' || plugin.currentPackageId === undefined) plugin.nextPackageId = definition.packageId
    const run: DynamicCordisRun = {
      pluginRunId: attempt.pluginRunId,
      packageId: definition.packageId,
      handlers: new Map(),
      handlerDisposers: [],
      reportedRuntimeErrors: new Set(),
      ...requestId === undefined ? {} : { startedForRequest: requestId },
    }
    if (definition.hostCode !== undefined) {
      const failure = await this.startHost(plugin, definition.hostCode, run)
      if (failure !== undefined) return { ok: false, ...failure }
    }
    plugin.run = run
    this.ctx.emit('cordis/dynamic-package', {
      pluginId: plugin.pluginId,
      packageId: definition.packageId,
      pluginRunId: run.pluginRunId,
      name: definition.name,
    })
    attempt.host = {
      status: run.fiber === undefined ? 'absent' : missingFor(this.ctx, run).length === 0 ? 'running' : 'waiting',
      waitingFor: missingFor(this.ctx, run),
    }
    if (definition.clientCode === undefined) {
      this.commitActivation(plugin, run)
    } else {
      attempt.status = 'client-pending'
      attempt.client = { status: 'pending', waitingFor: [] }
    }
    return {
      ok: true,
      pluginId: plugin.pluginId,
      packageId: definition.packageId,
      pluginRunId: run.pluginRunId,
      waitingFor: missingFor(this.ctx, run),
      startedHere: true,
    }
  }

  private async startHost(
    plugin: DynamicCordisPlugin,
    hostCode: string,
    run: DynamicCordisRun,
  ): Promise<CordisErrorDetails | undefined> {
    const handle = (method: unknown, fn: unknown): (() => void) => {
      const normalized = normalizeHandler(method, fn)
      run.handlers.set(normalized.method, normalized.handler)
      const dispose = (): void => {
        if (run.handlers.get(normalized.method) === normalized.handler) run.handlers.delete(normalized.method)
      }
      run.handlerDisposers.push(dispose)
      return dispose
    }
    try {
      const sandbox = createSandbox(plugin.pluginId, { handle })
      const evaluated = await evaluateHostCode(sandbox, hostCode, plugin.pluginId, this.resolved.vmTimeoutMs)
      if (!isPlugin(evaluated)) {
        throw new Error(evaluated === undefined
          ? 'the Host half returned `undefined` — did you forget `return`?'
          : 'the Host half must return a Plugin function or an object with apply(ctx)')
      }
      run.fiber = await startHostHalf(
        this.requireGroup(),
        evaluated,
        (error) => { this.steerGuardFailure(plugin, run, 'Host', errorDetails(error)) },
      )
      return undefined
    } catch (error) {
      for (const dispose of run.handlerDisposers.splice(0)) dispose()
      return errorDetails(error)
    }
  }

  private async settleActivation(
    plugin: DynamicCordisPlugin | undefined,
    resolution: DynamicCordisRunResolution,
    requestId?: ApprovalRequestId,
  ): Promise<DynamicCordisRunResponse> {
    if (plugin === undefined) return { ok: false, reason: 'plugin-missing', message: 'the dynamic plugin was removed during activation' }
    const attempt = plugin.latestRun
    if (!resolution.ok) {
      if (resolution.reason === 'rejected') {
        if (attempt !== undefined) {
          attempt.status = 'rejected'
          attempt.error = this.diagnostic(plugin, attempt, 'approval', resolution.message ?? 'the run request was declined')
          attempt.client = { status: 'stopped', waitingFor: [] }
        }
        return { ok: false, reason: 'rejected', message: resolution.message ?? 'the run request was declined' }
      }
      const run = plugin.run
      const ownsRun = run !== undefined
        && resolution.pluginRunId === run.pluginRunId
        && (requestId === undefined || run.startedForRequest === requestId)
        && resolution.startedHere !== false
      if (ownsRun) await this.retract(plugin)
      if (attempt !== undefined && (resolution.pluginRunId === undefined || attempt.pluginRunId === resolution.pluginRunId)) {
        this.failAttempt(
          plugin,
          attempt,
          resolution.reason === 'host-half-failed' ? 'host-apply' : 'client-apply',
          {
            message: resolution.message ?? resolution.reason,
            ...resolution.stack === undefined ? {} : { stack: resolution.stack },
          },
        )
      }
      return {
        ok: false,
        reason: resolution.reason,
        message: resolution.message ?? resolution.reason,
        ...resolution.stack === undefined ? {} : { stack: resolution.stack },
      }
    }
    const run = plugin.run
    if (run === undefined || run.pluginRunId !== resolution.pluginRunId) {
      return { ok: false, reason: 'client-half-failed', message: `activation "${resolution.pluginRunId}" is no longer active` }
    }
    if (attempt !== undefined && attempt.pluginRunId === run.pluginRunId) {
      attempt.client = {
        status: resolution.waitingFor === undefined || resolution.waitingFor.length === 0 ? 'running' : 'waiting',
        waitingFor: resolution.waitingFor ?? [],
      }
    }
    this.commitActivation(plugin, run)
    return {
      ...this.runResponse(plugin, {
        ok: true,
        pluginId: plugin.pluginId,
        packageId: run.packageId,
        pluginRunId: run.pluginRunId,
        waitingFor: missingFor(this.ctx, run),
        startedHere: false,
      }),
      ...resolution.waitingFor === undefined ? {} : { clientWaitingFor: resolution.waitingFor },
    }
  }

  private commitActivation(plugin: DynamicCordisPlugin, run: DynamicCordisRun): void {
    plugin.currentPackageId = run.packageId
    delete plugin.nextPackageId
    delete run.startedForRequest
    const attempt = plugin.latestRun
    if (attempt?.pluginRunId === run.pluginRunId) {
      attempt.status = attempt.host.status === 'waiting' || attempt.client.status === 'waiting' ? 'waiting' : 'running'
      delete attempt.approvalRequestId
      delete attempt.requiresApproval
      delete attempt.error
    }
  }

  private runResponse(
    plugin: DynamicCordisPlugin,
    started: Extract<DynamicCordisHostHalfResult, { ok: true }>,
  ): Extract<DynamicCordisRunResponse, { ok: true }> {
    return {
      ok: true,
      status: 'running',
      pluginId: plugin.pluginId,
      packageId: started.packageId,
      pluginRunId: started.pluginRunId,
      waitingFor: started.waitingFor,
      currentPackageId: started.packageId,
      mode: plugin.latestRun?.pluginRunId === started.pluginRunId ? plugin.latestRun.mode : 'run',
    }
  }

  private announceResolved(
    requestId: ApprovalRequestId,
    resolution: DynamicCordisRunResolution,
    override?: RequestRunOutcome,
  ): void {
    const outcome = override ?? (resolution.ok ? 'approved' : resolution.reason === 'rejected' ? 'rejected' : 'failed')
    this.ctx.emit('cordis/request-run-resolved', { requestId, outcome })
  }

  private steerRunOutcome(
    pending: DynamicCordisPendingRequest,
    settled: DynamicCordisRunResponse,
  ): void {
    const agents = this.rootCtx.get('agents')
    const agent = agents?.get(pending.agentId)
    if (agent === undefined) return
    const plugin = this.registry.get(pending.pluginId)
    const identity = `${pending.pluginId}/${pending.packageId} (${pending.pluginRunId})`
    let text: string
    if (settled.ok) {
      text = `Cordis ${pending.mode} ${identity} completed successfully. `
        + `currentPackageId is ${settled.currentPackageId ?? pending.packageId}. Continue using the running Plugin.`
    } else if (settled.reason === 'rejected') {
      text = `The user rejected Cordis ${pending.mode} ${identity}. `
        + 'Do not request the same activation again unless the user asks.'
    } else {
      const returnedStatus = pending.requiresApproval ? 'awaiting-approval' : 'starting'
      text = `Cordis ${pending.mode} ${identity} failed after cordis_run returned ${returnedStatus}: `
        + `${settled.reason}\n${formatErrorDetails(settled)}\n`
        + `currentPackageId: ${plugin?.currentPackageId ?? 'none'}\n`
        + `nextPackageId: ${plugin?.nextPackageId ?? pending.packageId}\n`
        + 'Inspect the failed Package, correct it on the same Plugin when needed, and retry the activation autonomously.'
    }
    agent.steer(createUserMessage({
      content: [{ type: 'text', text }],
      source: { kind: 'plugin', plugin: 'cordis-host-runner' },
    }))
  }

  private steerRenderFailure(
    agent: Agent,
    plugin: DynamicCordisPlugin,
    definition: DynamicCordisDefinition,
    pluginRunId: CordisDynamicPluginRunId,
    failure: DynamicCordisRenderFailure,
  ): void {
    agent.steer(createUserMessage({
      content: [{
        type: 'text',
        text: `Cordis Client UI ${plugin.pluginId}/${definition.packageId} (${pluginRunId}) failed while rendering `
          + `Slot "${failure.slot}" after activation.\n`
          + `${formatErrorDetails(failure)}\n`
          + `entryAbdicated: ${failure.abdicated}\n`
          + 'Inspect the failed Package, fix the Client code by defining a new Package on the same Plugin, and '
          + 'activate that Package autonomously with cordis_run mode:"update".',
      }],
      source: { kind: 'plugin', plugin: 'cordis-host-runner' },
    }))
  }

  private steerHostHandlerFailure(
    plugin: DynamicCordisPlugin,
    run: DynamicCordisRun,
    method: string,
    failure: CordisErrorDetails,
  ): void {
    const reportKey = `Host\u0000handler\u0000${method}\u0000${failure.message}`
    if (!this.claimRuntimeFailure(plugin, run, reportKey)) return
    const agents = this.rootCtx.get('agents')
    const agent = agents?.get(plugin.sessionId)
    if (agent === undefined) return
    agent.steer(createUserMessage({
      content: [{
        type: 'text',
        text: `Cordis Host handler ${plugin.pluginId}/${run.packageId} (${run.pluginRunId}) failed when the Client called `
          + `host.call(${JSON.stringify(method)}).\n`
          + `${formatErrorDetails(failure)}\n`
          + 'The Plugin remains running. Inspect this Package, correct the Host code on the same Plugin, and activate '
          + 'the new Package autonomously with cordis_run mode:"update". If the handler needs a Service, either declare '
          + 'that Service in the returned Plugin inject list or read it with ctx.get(name) and handle undefined.',
      }],
      source: { kind: 'plugin', plugin: 'cordis-host-runner' },
    }))
  }

  /* jscpd:ignore-start */
  private steerGuardFailure(
    plugin: DynamicCordisPlugin,
    run: DynamicCordisRun,
    platform: 'Host' | 'Client',
    failure: CordisErrorDetails,
  ): void {
    const reportKey = `${platform}\u0000guard\u0000${failure.message}`
    if (!this.claimRuntimeFailure(plugin, run, reportKey)) return
    const agents = this.rootCtx.get('agents')
    const agent = agents?.get(plugin.sessionId)
    if (agent === undefined) return
    agent.steer(createUserMessage({
      content: [{
        type: 'text',
        text: `Cordis ${platform} guard rejected runtime code in ${plugin.pluginId}/${run.packageId} `
          + `(${run.pluginRunId}) after activation.\n${formatErrorDetails(failure)}\n`
          + 'The Plugin remains running. Inspect this Package, define a corrected Package on the same Plugin, and '
          + 'activate it autonomously with cordis_run mode:"update".',
      }],
      source: { kind: 'plugin', plugin: 'cordis-host-runner' },
    }))
  }
  /* jscpd:ignore-end */

  private claimRuntimeFailure(plugin: DynamicCordisPlugin, run: DynamicCordisRun, key: string): boolean {
    const attempt = plugin.latestRun
    if (plugin.run !== run || attempt?.pluginRunId !== run.pluginRunId
      || (attempt.status !== 'running' && attempt.status !== 'waiting')) return false
    if (run.reportedRuntimeErrors.has(key)) return false
    run.reportedRuntimeErrors.add(key)
    return true
  }

  private injectUserRunOutcome(
    agent: Agent,
    pluginId: CordisDynamicPluginId,
    settled: DynamicCordisRunResponse,
  ): void {
    const plugin = this.owned(agent, pluginId)
    let text: string
    if (settled.ok) {
      text = `The user manually ran Cordis Plugin ${pluginId}, Package ${settled.packageId}, `
        + `as ${settled.pluginRunId}. The activation succeeded; currentPackageId is ${settled.currentPackageId}.`
    } else {
      const attempt = plugin?.latestRun
      text = `The user manually ran Cordis Plugin ${pluginId}`
        + `${attempt === undefined ? '' : `, Package ${attempt.packageId}, as ${attempt.pluginRunId}`}, but it failed: `
        + `${settled.reason}\n${formatErrorDetails(settled)}\n`
        + `currentPackageId: ${plugin?.currentPackageId ?? 'none'}\n`
        + `nextPackageId: ${plugin?.nextPackageId ?? 'none'}`
    }
    this.injectUserContext(agent, text)
  }

  private injectUserContext(agent: Agent, text: string): void {
    const agents = this.rootCtx.get('agents')
    if (agents?.get(agent.id) !== agent) return
    agent.inject(createUserMessage({
      content: [{ type: 'text', text }],
      source: { kind: 'plugin', plugin: 'cordis-host-runner' },
    }))
  }

  private cancelPending(pluginId: CordisDynamicPluginId, message: string): void {
    const requestId = this.registry.pendingRequestFor(pluginId)
    if (requestId === undefined) return
    const pending = this.registry.claimRequest(requestId)
    if (pending === undefined) return
    const plugin = this.registry.get(pluginId)
    if (plugin?.latestRun?.pluginRunId === pending.pluginRunId) {
      plugin.latestRun.status = 'cancelled'
      plugin.latestRun.error = this.diagnostic(plugin, plugin.latestRun, 'approval', message)
      delete plugin.latestRun.approvalRequestId
      delete plugin.latestRun.requiresApproval
    }
    this.announceResolved(requestId, { ok: false, reason: 'rejected' }, 'cancelled')
  }

  private createAttempt(plan: ActivationPlan): DynamicCordisRunAttempt {
    return {
      pluginRunId: CordisDynamicPluginRunId(this.registry.mintPluginRunId()),
      packageId: plan.definition.packageId,
      mode: plan.mode,
      status: 'starting-host',
      host: {
        status: plan.definition.hostCode === undefined ? 'absent' : 'pending',
        waitingFor: [],
      },
      client: {
        status: plan.definition.clientCode === undefined ? 'absent' : 'pending',
        waitingFor: [],
      },
    }
  }

  private failAttempt(
    plugin: DynamicCordisPlugin,
    attempt: DynamicCordisRunAttempt,
    phase: NonNullable<DynamicCordisRunAttempt['error']>['phase'],
    failure: CordisErrorDetails,
  ): void {
    attempt.status = 'failed'
    attempt.error = this.diagnostic(plugin, attempt, phase, failure)
    if (phase.startsWith('host')) attempt.host = { status: 'failed', waitingFor: [], error: failure.message }
    else attempt.client = { status: 'failed', waitingFor: [], error: failure.message }
  }

  private diagnostic(
    plugin: DynamicCordisPlugin,
    attempt: DynamicCordisRunAttempt,
    phase: NonNullable<DynamicCordisRunAttempt['error']>['phase'],
    failure: CordisErrorDetails | string,
  ): NonNullable<DynamicCordisRunAttempt['error']> {
    const details = typeof failure === 'string' ? { message: failure } : failure
    return {
      phase,
      ...details,
      pluginId: plugin.pluginId,
      packageId: attempt.packageId,
      pluginRunId: attempt.pluginRunId,
    }
  }

  private async retract(plugin: DynamicCordisPlugin): Promise<void> {
    const run = plugin.run
    if (run === undefined) return
    delete plugin.run
    for (const dispose of run.handlerDisposers.splice(0)) dispose()
    if (run.fiber !== undefined) await run.fiber.dispose()
    this.ctx.emit('cordis/dynamic-retract', {
      pluginId: plugin.pluginId,
      packageId: run.packageId,
      pluginRunId: run.pluginRunId,
    })
  }

  private owned(agent: Agent, pluginId: CordisDynamicPluginId): DynamicCordisPlugin | undefined {
    const plugin = this.registry.get(pluginId)
    return plugin?.sessionId === agent.id ? plugin : undefined
  }

  private requireGroup(): Fiber {
    this.group ??= this.rootCtx.plugin({ name: 'cordis-dynamic', apply: () => {} })
    return this.group
  }
}

function missingFor(ctx: Context, run: DynamicCordisRun): string[] {
  return run.fiber === undefined ? [] : missingServices(ctx, run.fiber)
}

function missingPluginMessage(id: CordisDynamicPluginId): string {
  return `no dynamic plugin "${id}" in this process — it may have been removed or lost on DSH restart`
}

function errorDetails(error: unknown): CordisErrorDetails {
  if (typeof error !== 'object' || error === null) return { message: String(error) }
  const message = 'message' in error && typeof error.message === 'string'
    ? error.message
    : Object.prototype.toString.call(error)
  const stack = 'stack' in error && typeof error.stack === 'string' ? error.stack : undefined
  return { message, ...stack === undefined ? {} : { stack } }
}

function formatErrorDetails(failure: CordisErrorDetails): string {
  return `message: ${failure.message}`
    + (failure.stack === undefined ? '' : `\nstack:\n${failure.stack}`)
}

function cloneAttempt(attempt: DynamicCordisRunAttempt): DynamicCordisRunAttempt {
  return {
    ...attempt,
    host: { ...attempt.host, waitingFor: [...attempt.host.waitingFor] },
    client: { ...attempt.client, waitingFor: [...attempt.client.waitingFor] },
    ...attempt.error === undefined ? {} : { error: { ...attempt.error } },
  }
}

export default DynamicCordisRunnerService