/**
 * Workspace package invariant checks for package-manager-independent quality
 * gates.
 *
 * Run: `tsx scripts/check-workspace-constraints.ts`.
 */

import { existsSync, readdirSync, readFileSync } from 'node:fs'
import { join, relative, resolve } from 'node:path'

const root = resolve(import.meta.dirname, '..')
// vendor/* is single-level; packages/<group>/<pkg> nests one level deeper
// (the group dirs — core/llm/bash/… — are pure containers with no manifest).
const workspaceGlobs = [
  { dir: 'vendor', depth: 1 },
  { dir: 'packages', depth: 2 },
] as const
const vendoredPackages = new Set([
  'cordis',
  'cosmokit',
  'schemastery',
  '@cordisjs/plugin-loader',
  '@cordisjs/plugin-include',
  '@cordisjs/plugin-group',
  '@cordisjs/plugin-timer',
  '@cordisjs/plugin-hmr',
  '@cordisjs/plugin-logger-console',
])

const localArtifactDirs = new Set(['node_modules'])

/** The subset of package.json fields this constraint check cares about. */
interface PackageManifest {
  name?: string
  version?: string
  private?: boolean
  type?: string
  main?: string
  types?: string
  bin?: string | Record<string, string>
  exports?: Record<
    string,
    | string
    | {
      types?: string
      default?: string
    }
    | null
    | undefined
  >
  files?: string[]
  peerDependencies?: Record<string, string>
  devDependencies?: Record<string, string>
}

/** One workspace manifest and its repo-relative path. */
interface WorkspaceManifest {
  dir: string
  manifest: PackageManifest
}

function readJson(path: string): PackageManifest {
  return JSON.parse(readFileSync(path, 'utf8')) as PackageManifest
}

const rootManifest = readJson(join(root, 'package.json'))
const repositoryVersion = rootManifest.version

/** Repo-relative dirs holding a package.json, walked to the configured depth. */
function packageDirs(base: string, depth: number): string[] {
  if (depth === 1) {
    return readdirSync(join(root, base), { withFileTypes: true })
      .filter(entry => entry.isDirectory())
      .filter(entry => !localArtifactDirs.has(entry.name))
      .filter(entry => existsSync(join(root, base, entry.name, 'package.json')))
      .map(entry => join(base, entry.name))
  }
  return readdirSync(join(root, base), { withFileTypes: true })
    .filter(entry => entry.isDirectory())
    .filter(entry => !localArtifactDirs.has(entry.name))
    .flatMap(group => packageDirs(join(base, group.name), depth - 1))
}

function workspaceManifests(): WorkspaceManifest[] {
  const manifests: WorkspaceManifest[] = [
    { dir: '.', manifest: rootManifest },
  ]

  for (const { dir: base, depth } of workspaceGlobs) {
    for (const dir of packageDirs(base, depth)) {
      manifests.push({ dir, manifest: readJson(join(root, dir, 'package.json')) })
    }
  }

  return manifests
}

const packageFileExtras: Readonly<Record<string, readonly string[]>> = {
  '@deepseek-ai/dsh-helper': ['lib/assets'],
  '@deepseek-ai/dsh-tui': ['lib/prompt.js'],
  '@deepseek-ai/dsh-scripts': [
    'lib/dev/tsdown-config.js',
    'lib/local-plugin-loader-hooks.js',
    'lib/assets',
  ],
}

function sameStringList(actual: readonly string[] | undefined, expected: readonly string[]): boolean {
  return !!actual && actual.length === expected.length && actual.every((value, index) => value === expected[index])
}

function expectedDshPackageFiles(manifest: PackageManifest): readonly string[] {
  const extras = manifest.name ? packageFileExtras[manifest.name] ?? [] : []
  return [
    'lib/index.js',
    // Every package publishes its invariant ownership companion as a separate
    // bundle; the package-invariant gate validates the companion itself.
    'lib/invariant.js',
    ...manifest.bin ? ['lib/bin.js'] : [],
    ...manifest.exports?.['./worker'] ? ['lib/worker.cjs'] : [],
    // UI plugin packages ship their browser bundle beside the node lib
    // (single-artifact ruling: dist/ retired, ./client resolves lib/client.js).
    // Keyed on the artifact path, not the subpath name: apiproxy's ./client is
    // a browser-safe source channel, not a bundle.
    ...exportDefault(manifest, './client') === './lib/client.js' ? ['lib/client.js'] : [],
    // runtime's shell-held loader subpath ships as its own bundle beside the client half.
    ...exportDefault(manifest, './loader') === './lib/loader.js' ? ['lib/loader.js'] : [],
    // web-react's store subpath ships its own bundle (single-entry builds; no shared chunk).
    ...exportDefault(manifest, './store') === './lib/store/index.js' ? ['lib/store/index.js'] : [],
    ...extras,
    // Subpaths whose runtime default is the tsc-emitted tree (lib/types/*.js —
    // browser-safe source channels rehomed off src so plain Node can import
    // them without type stripping) publish the emitted JS alongside the
    // declarations.
    ...usesEmittedTreeDefaults(manifest) ? ['lib/types/**/*.js'] : [],
    'lib/types/**/*.d.ts',
    'lib/types/**/*.d.ts.map',
    'src',
  ]
}

/** Runtime target of an export entry: conditional `default`, or the bare-string shorthand. */
function exportDefault(manifest: PackageManifest, subpath: string): string | undefined {
  const entry = manifest.exports?.[subpath]
  if (typeof entry === 'string') return entry
  if (typeof entry === 'object' && entry !== null) return entry.default
  return undefined
}

/** Whether any export's runtime default points into the tsc-emitted lib/types tree. */
function usesEmittedTreeDefaults(manifest: PackageManifest): boolean {
  return Object.keys(manifest.exports ?? {}).some(subpath =>
    exportDefault(manifest, subpath)?.startsWith('./lib/types/') === true)
}

function checkWorkspace({ dir, manifest }: WorkspaceManifest): string[] {
  const errors: string[] = []
  const label = manifest.name ?? dir

  if (manifest.private !== true) {
    errors.push(`${label}: package.json must set "private": true`)
  }

  if (manifest.name && vendoredPackages.has(manifest.name)) {
    return errors
  }

  if (manifest.name?.startsWith('@deepseek-ai/dsh-') && manifest.name !== '@deepseek-ai/dsh-root') {
    const peer = manifest.peerDependencies?.cordis
    const dev = manifest.devDependencies?.cordis

    if (!peer) errors.push(`${label}: cordis must be a peerDependency`)
    if (!dev) errors.push(`${label}: cordis must also be a devDependency`)
    if (peer && dev && peer !== dev) {
      errors.push(`${label}: cordis peer (${peer}) and dev (${dev}) ranges must match`)
    }
    if (manifest.version !== repositoryVersion) {
      errors.push(`${label}: package.json version must match root version ${repositoryVersion ?? '(missing)'}`)
    }
    if (manifest.type !== 'module') {
      errors.push(`${label}: package.json must set "type": "module"`)
    }
    if (manifest.main !== 'lib/index.js') {
      errors.push(`${label}: package.json must set "main": "lib/index.js"`)
    }
    if (manifest.types !== 'lib/types/index.d.ts') {
      errors.push(`${label}: package.json must set "types": "lib/types/index.d.ts"`)
    }
    const rootExport = manifest.exports?.['.']
    const rootEntry = typeof rootExport === 'object' && rootExport !== null ? rootExport : undefined
    if (rootEntry?.types !== './lib/types/index.d.ts') {
      errors.push(`${label}: package.json exports["."].types must be "./lib/types/index.d.ts"`)
    }
    if (rootEntry?.default !== './lib/index.js') {
      errors.push(`${label}: package.json exports["."].default must be "./lib/index.js"`)
    }
    const invariantRaw = manifest.exports?.['./invariant']
    const invariantExport = typeof invariantRaw === 'object' && invariantRaw !== null ? invariantRaw : undefined
    if (invariantExport?.types !== undefined && invariantExport.types !== './lib/types/invariant.d.ts') {
      errors.push(`${label}: package.json exports["./invariant"].types must be "./lib/types/invariant.d.ts"`)
    }
    if (invariantExport?.default !== undefined && invariantExport.default !== './lib/invariant.js') {
      errors.push(`${label}: package.json exports["./invariant"].default must be "./lib/invariant.js"`)
    }
    if (invariantExport && (invariantExport.types === undefined || invariantExport.default === undefined)) {
      errors.push(`${label}: package.json exports["./invariant"] must declare both types and default targets`)
    }
    const expectedFiles = expectedDshPackageFiles(manifest)
    if (!sameStringList(manifest.files, expectedFiles)) {
      errors.push(`${label}: package.json files must be ${JSON.stringify(expectedFiles)}`)
    }
  }

  return errors.map(error => `${relative(root, join(root, dir, 'package.json'))}: ${error}`)
}

/**
 * Enforce `packages/<group>/<pkg>`: groups are open-named containers without a
 * package.json, and packages may be neither flat nor more deeply nested.
 */
function checkHierarchyShape(): string[] {
  const errors: string[] = []
  const packagesRoot = join(root, 'packages')
  for (const group of readdirSync(packagesRoot, { withFileTypes: true })) {
    if (!group.isDirectory()) continue
    const groupRel = join('packages', group.name)
    if (existsSync(join(packagesRoot, group.name, 'package.json'))) {
      errors.push(`${groupRel}: a group dir must not contain a package.json — packages live at packages/<group>/<pkg>, not directly under packages/`)
      continue
    }
    for (const pkg of readdirSync(join(packagesRoot, group.name), { withFileTypes: true })) {
      if (!pkg.isDirectory()) continue
      if (localArtifactDirs.has(pkg.name)) continue
      const pkgRel = join(groupRel, pkg.name)
      if (!existsSync(join(packagesRoot, group.name, pkg.name, 'package.json'))) {
        errors.push(`${pkgRel}: expected a package here (no package.json found) — the hierarchy is exactly packages/<group>/<pkg>, no deeper nesting`)
      }
    }
  }
  return errors
}

function checkRepositoryVersion(): string[] {
  if (repositoryVersion && /^\d+\.\d+\.\d+$/.test(repositoryVersion)) return []
  return ['package.json: version must be stable X.Y.Z']
}

const errors = [
  ...checkRepositoryVersion(),
  ...workspaceManifests().flatMap(checkWorkspace),
  ...checkHierarchyShape(),
]
if (errors.length > 0) {
  console.error(errors.join('\n'))
  process.exitCode = 1
}