import { describe, expect, it } from 'vitest'
import { Context } from 'cordis'
import AgentRegistry from '@deepseek-ai/dsh-agent'
import AgentLoop from '@deepseek-ai/dsh-agent-loop'
import LlmService, { createUserMessage, LlmError  } from '@deepseek-ai/dsh-llm'
import type { LlmFailure, ResolvedRetryPolicy } from '@deepseek-ai/dsh-llm'
import SessionStore, { SessionId } from '@deepseek-ai/dsh-session'
import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
import ToolRegistry from '@deepseek-ai/dsh-tools'
import { MockAdapter, textResponse } from './mock-adapter.ts'

async function harness(adapter: MockAdapter): Promise<Context> {
  const ctx = new Context()
  await ctx.plugin(LlmService)
  await ctx.plugin(SessionStore)
  await ctx.plugin(SystemPrompt)
  await ctx.plugin(ToolRegistry)
  await ctx.plugin(AgentRegistry)
  await ctx.plugin(AgentLoop, { agents: [] })
  ctx.llm.registerAdapter(['mock'], adapter)
  return ctx
}

function fail(message: string, code: string): () => never {
  return () => {
    throw new LlmError(message, code)
  }
}

describe('agent/request-error', () => {
  it('does not offer middleware failures to request recovery', async () => {
    const adapter = new MockAdapter([textResponse('unused')])
    const ctx = await harness(adapter)
    const agent = ctx.agentLoop.create(SessionId('request-error-narrow'), { provider: 'mock', model: 'mock' })
    let recoveries = 0
    ctx.on('agent/request', () => {
      throw new LlmError('middleware failed', 'MIDDLEWARE')
    })
    ctx.on('agent/request-error', async () => {
      recoveries += 1
    })

    agent.followup(createUserMessage({ content: [{ type: 'text', text: 'go' }], source: { kind: 'user' } }))
    await agent.whenIdle()

    expect(recoveries).toBe(0)
    expect(adapter.requests).toHaveLength(0)
  })

  it('lets each failed request return a retry action before its turn closes', async () => {
    const adapter = new MockAdapter([
      fail('busy', 'RATE_LIMIT'),
      fail('unavailable', 'SERVICE_UNAVAILABLE'),
      textResponse('ok'),
    ])
    const ctx = await harness(adapter)
    const agent = ctx.agentLoop.create(SessionId('request-error-retry'), { provider: 'mock', model: 'mock' })
    const seen: {
      turn: number
      step: number
      failure: LlmFailure
      priorFailures: readonly LlmFailure[]
      retryPolicy: ResolvedRetryPolicy | undefined
    }[] = []
    const statuses: string[] = []
    const settledTurns: number[] = []
    ctx.on('agent/status', (subject, status) => {
      if (subject === agent) statuses.push(status)
    })
    ctx.on('agent/settled', (subject, turn) => {
      if (subject === agent) settledTurns.push(turn)
    })
    ctx.on('agent/request-error', async (
      subject, turn, step, _error, failure, priorFailures, retryPolicy,
    ) => {
      expect(subject).toBe(agent)
      expect(agent.session.events.at(-1)).toMatchObject({
        type: 'step/end',
        data: { turn, step },
      })
      seen.push({ turn, step, failure, priorFailures, retryPolicy })
      return { kind: 'retry' }
    })

    agent.followup(createUserMessage({ content: [{ type: 'text', text: 'go' }], source: { kind: 'user' } }))
    await agent.whenIdle()

    expect(seen.map(item => ({
      turn: item.turn,
      step: item.step,
      code: item.failure.code,
    }))).toEqual([
      {
        turn: 1,
        step: 1,
        code: 'RATE_LIMIT',
      },
      {
        turn: 2,
        step: 1,
        code: 'SERVICE_UNAVAILABLE',
      },
    ])
    expect(agent.session.events.filter(event => event.type === 'turn/start').map(event => event.data.trigger))
      .toEqual([
        { kind: 'message', source: { kind: 'user' } },
        { kind: 'retry' },
        { kind: 'retry' },
      ])
    expect(seen.map(item => item.priorFailures.map(failure => failure.code)))
      .toEqual([[], ['RATE_LIMIT']])
    expect(seen.map(item => item.retryPolicy)).toEqual([
      expect.objectContaining({ mode: 'normal' }),
      expect.objectContaining({ mode: 'normal' }),
    ])
    expect(statuses).toEqual(['running', 'idle'])
    expect(settledTurns).toEqual([3])
  })

  it('lets cancellation win over a retry action', async () => {
    const adapter = new MockAdapter([fail('busy', 'RATE_LIMIT'), textResponse('unused')])
    const ctx = await harness(adapter)
    const agent = ctx.agentLoop.create(SessionId('request-error-cancel'), { provider: 'mock', model: 'mock' })
    ctx.on('agent/request-error', async (subject) => {
      subject.cancel({ kind: 'user' })
      return { kind: 'retry' }
    })

    agent.followup(createUserMessage({ content: [{ type: 'text', text: 'go' }], source: { kind: 'user' } }))
    await agent.whenIdle()

    expect(adapter.requests).toHaveLength(1)
    expect(agent.session.events.filter(event => event.type === 'turn/start')).toHaveLength(1)
    expect(agent.session.events.find(event => event.type === 'turn/end')).toMatchObject({
      type: 'turn/end',
      data: { reason: { kind: 'aborted' } },
    })
  })

  it('does not retry when the recovery listener fails before returning its action', async () => {
    const adapter = new MockAdapter([fail('busy', 'RATE_LIMIT'), textResponse('unused')])
    const ctx = await harness(adapter)
    const agent = ctx.agentLoop.create(SessionId('request-error-recovery-failed'), {
      provider: 'mock',
      model: 'mock',
    })
    ctx.on('agent/request-error', async () => {
      throw new Error('recovery failed')
    })

    agent.followup(createUserMessage({ content: [{ type: 'text', text: 'go' }], source: { kind: 'user' } }))
    await agent.whenIdle()

    expect(adapter.requests).toHaveLength(1)
    expect(agent.session.events.filter(event => event.type === 'turn/start')).toHaveLength(1)
    expect(agent.session.events.find(event => event.type === 'turn/end')).toMatchObject({
      type: 'turn/end',
      data: { reason: { kind: 'error' } },
    })
  })
})