/**
 * Vite dev middleware exposing one or more local doocus output trees.
 *
 * Each output dir is a "collection" (its own index.json + sidecars + source
 * root). The client can turn collections on/off; file paths are composite —
 * "<collectionId>/<relpath>" — so a single path identifies both the collection
 * and the file within it. All reads are local; nothing leaves the machine.
 *
 * Routes (path params are composite, query is ?path=/?q=):
 *   GET /api/collections                 available collections
 *   GET /api/tree?collections=a,b        merged tree of the active collections
 *   GET /api/detail?path=<c/rel>         node + extracted content + meta + text
 *   GET /api/original?path=<c/rel>       stream the original (Range-enabled)
 *   GET /api/meeting?path=<c/rel>        meetus review data for a meeting
 *   GET /api/meeting/frame?path=&file=   a meeting frame
 *   GET /api/runs/:cid  (cid=c/rel)      meetus-shaped run (for the embed)
 *   PUT /api/runs/:cid/review            write the meeting's review.json
 *   GET /api/search?q=&collections=a,b   search cached text across active cols
 */
import type { Plugin } from 'vite'
import type { IncomingMessage, ServerResponse } from 'node:http'
import { spawn } from 'node:child_process'
import fs from 'node:fs'
import fsp from 'node:fs/promises'
import path from 'node:path'

interface Options {
  outputDirs: string[]    // explicit output dirs (env)
  outputsRoot: string     // managed root: UI-scanned sources land here
  repoRoot: string        // where process_tree.py lives (run via uv)
}

interface Collection {
  id: string
  name: string
  dir: string
  indexPath: string
}

interface Node {
  path: string
  name: string
  ext: string
  family: string
  mode: 'extracted' | 'meeting' | 'link'
  bytes: number
  modified: string
  url: string | null
  out?: string
  title?: string
  warnings?: string[]
}

interface Index {
  root: string
  files: Node[]
  counts?: Record<string, number>
}

const TEXT_EXTS = new Set(['md', 'markdown', 'txt', 'json', 'yaml', 'yml', 'csv', 'html', 'htm'])

const MIME: Record<string, string> = {
  '.pdf': 'application/pdf', '.png': 'image/png', '.jpg': 'image/jpeg', '.jpeg': 'image/jpeg',
  '.html': 'text/html', '.htm': 'text/html', '.md': 'text/markdown', '.txt': 'text/plain',
  '.csv': 'text/csv', '.json': 'application/json', '.yaml': 'text/yaml', '.yml': 'text/yaml',
  '.docx': 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
  '.pptx': 'application/vnd.openxmlformats-officedocument.presentationml.presentation',
  '.xlsx': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
  '.mp4': 'video/mp4',
}

function buildCollections(dirs: string[]): Collection[] {
  const seen = new Map<string, number>()
  return dirs.map((d) => {
    const dir = path.resolve(d)
    let id = path.basename(dir) || 'output'
    const n = seen.get(id) ?? 0
    seen.set(id, n + 1)
    if (n > 0) id = `${id}-${n + 1}`
    return { id, name: id, dir, indexPath: path.join(dir, 'index.json') }
  })
}

export function doocusApi(opts: Options): Plugin {
  /** Collections discovered under the managed root (one subdir per source). */
  function discoverInRoot(): Collection[] {
    let subs: fs.Dirent[] = []
    try { subs = fs.readdirSync(opts.outputsRoot, { withFileTypes: true }) } catch { return [] }
    return subs
      .filter((d) => d.isDirectory() && fs.existsSync(path.join(opts.outputsRoot, d.name, 'index.json')))
      .map((d) => ({
        id: d.name, name: d.name,
        dir: path.join(opts.outputsRoot, d.name),
        indexPath: path.join(opts.outputsRoot, d.name, 'index.json'),
      }))
  }

  /** Current collections = explicit env dirs + managed-root subdirs (deduped,
   *  recomputed each request so UI scans appear without a restart). */
  function currentCollections(): Collection[] {
    const out: Collection[] = []
    const seen = new Set<string>()
    for (const c of [...buildCollections(opts.outputDirs), ...discoverInRoot()]) {
      if (out.some((o) => o.dir === c.dir)) continue
      let id = c.id, n = 1
      while (seen.has(id)) { n++; id = `${c.id}-${n}` }
      seen.add(id)
      out.push({ ...c, id })
    }
    return out
  }

  function collectionById(id: string): Collection | undefined {
    return currentCollections().find((c) => c.id === id)
  }

  function readIndexFor(c: Collection): Index | null {
    try { return JSON.parse(fs.readFileSync(c.indexPath, 'utf-8')) } catch { return null }
  }

  /** Split a composite "<collectionId>/<rel>" into its collection + rel path. */
  function splitPath(p: string): { col: Collection; rel: string } | null {
    const i = p.indexOf('/')
    const id = i < 0 ? p : p.slice(0, i)
    const rel = i < 0 ? '' : p.slice(i + 1)
    const col = collectionById(id)
    return col ? { col, rel } : null
  }

  /** Resolve a file within its collection's source root, rejecting traversal. */
  function originalAbs(index: Index, rel: string): string | null {
    const root = path.resolve(index.root)
    const abs = path.resolve(root, rel)
    if (abs !== root && !abs.startsWith(root + path.sep)) return null
    return abs
  }

  function meetusDir(col: Collection, rel: string): { dir: string; stem: string } {
    return { dir: path.join(col.dir, rel + '.meetus'), stem: path.parse(rel).name }
  }

  // Per-collection search index over cached text — rebuilt on index.json change.
  const searchCache = new Map<string, { mtime: number; entries: Array<{ path: string; hay: string; bytes: number }> }>()

  async function readCap(p: string | null, cap = 20_000_000): Promise<string> {
    if (!p) return ''
    try { return (await fsp.readFile(p, 'utf-8')).slice(0, cap) } catch { return '' }
  }

  async function buildSearchIndex(c: Collection): Promise<void> {
    const index = readIndexFor(c)
    let mtime = 0
    try { mtime = fs.statSync(c.indexPath).mtimeMs } catch { /* */ }
    const entries: Array<{ path: string; hay: string; bytes: number }> = []
    for (const f of index?.files ?? []) {
      let text = `${f.path} ${f.title ?? ''}`
      if (f.mode === 'extracted' && f.out) {
        text += ' ' + await readCap(path.join(c.dir, f.out, 'content.md'))
      } else if (f.mode === 'meeting') {
        const { dir, stem } = meetusDir(c, f.path)
        text += ' ' + await readCap(path.join(dir, `${stem}_enhanced.txt`))
      } else if (TEXT_EXTS.has(f.ext) && index) {
        text += ' ' + await readCap(originalAbs(index, f.path))
      }
      entries.push({ path: `${c.id}/${f.path}`, hay: text.toLowerCase(), bytes: f.bytes })
    }
    searchCache.set(c.id, { mtime, entries })
  }

  return {
    name: 'doocus-api',
    configureServer(server) {
      const cols = currentCollections()
      server.config.logger.info(
        `[doocus-api] ${cols.length} collection(s); managed root: ${opts.outputsRoot}`)
      server.middlewares.use('/api', (req, res, next) => {
        const url = new URL(req.url ?? '/', 'http://localhost')
        const parts = url.pathname.split('/').filter(Boolean)
        handle(req, res, parts, url.searchParams).catch((err) => {
          server.config.logger.error(`[doocus-api] ${String(err)}`)
          sendJson(res, 500, { error: String(err) })
        }).then((handled) => { if (!handled) next() })
      })
    },
  }

  async function handle(req: IncomingMessage, res: ServerResponse, parts: string[], q: URLSearchParams): Promise<boolean> {
    if (parts[0] === 'collections') { listCollections(res); return true }
    if (parts[0] === 'scan' && req.method === 'POST') { await runScan(req, res, false); return true }
    if (parts[0] === 'rescan' && req.method === 'POST') { await runScan(req, res, true); return true }
    if (parts[0] === 'tree') { getTree(res, q.get('collections')); return true }
    if (parts[0] === 'detail') { await getDetail(res, q.get('path') ?? ''); return true }
    if (parts[0] === 'original') { await serveOriginal(res, q.get('path') ?? '', req.headers.range); return true }
    if (parts[0] === 'meeting' && parts[1] === 'frame') { serveMeetingFrame(res, q.get('path') ?? '', q.get('file') ?? ''); return true }
    if (parts[0] === 'meeting') { await getMeeting(res, q.get('path') ?? ''); return true }
    if (parts[0] === 'search') { await search(res, q.get('q') ?? '', q.get('collections')); return true }
    if (parts[0] === 'runs' && parts.length >= 2) {
      const id = decodeURIComponent(parts[1])
      if (parts.length === 2 && req.method === 'GET') { await getRunShaped(res, id); return true }
      if (parts.length === 3 && parts[2] === 'review' && req.method === 'PUT') { await saveRunReview(req, res, id); return true }
    }
    return false
  }

  function listCollections(res: ServerResponse): void {
    const out = currentCollections().map((c) => {
      const idx = readIndexFor(c)
      return { id: c.id, name: c.name, available: !!idx, count: idx?.files.length ?? 0 }
    })
    sendJson(res, 200, { collections: out })
  }

  /** Run process_tree.py over a source folder (new scan) or an existing
   *  collection's recorded source (rescan), writing to the managed root. */
  async function runScan(req: IncomingMessage, res: ServerResponse, rerun: boolean): Promise<void> {
    let body: { source?: string; id?: string }
    try { body = JSON.parse((await readBody(req)) || '{}') } catch { sendJson(res, 400, { error: 'invalid JSON' }); return }

    let source: string
    let dir: string
    if (rerun) {
      const col = body.id ? collectionById(body.id) : undefined
      const idx = col ? readIndexFor(col) : null
      if (!col || !idx?.root) { sendJson(res, 404, { error: 'collection not found' }); return }
      source = idx.root
      dir = col.dir
    } else {
      source = (body.source ?? '').trim()
      if (!source || !isDir(source)) { sendJson(res, 400, { error: `not a directory: ${source}` }); return }
      const slug = path.basename(path.resolve(source)).replace(/[^\w.-]+/g, '_') || 'source'
      dir = path.join(opts.outputsRoot, slug)
      fs.mkdirSync(opts.outputsRoot, { recursive: true })
    }

    try {
      await runProcessTree(source, dir)
      sendJson(res, 200, { ok: true, id: path.basename(dir) })
    } catch (e) {
      sendJson(res, 500, { error: String(e) })
    }
  }

  /** Spawn `uv run python process_tree.py <source> --output <dir>` at repoRoot. */
  function runProcessTree(source: string, dir: string): Promise<void> {
    return new Promise((resolve, reject) => {
      const child = spawn('uv', ['run', 'python', 'process_tree.py', source, '--output', dir],
        { cwd: opts.repoRoot })
      let err = ''
      child.stderr.on('data', (d) => { err += d })
      child.on('error', reject)
      child.on('close', (code) => code === 0 ? resolve() : reject(new Error(err || `exit ${code}`)))
    })
  }

  function getTree(res: ServerResponse, activeCsv: string | null): void {
    const active = activeCsv ? new Set(activeCsv.split(',').filter(Boolean)) : null
    const cols = currentCollections().filter((c) => !active || active.has(c.id))
    const files: Array<Node & { collection: string }> = []
    const counts: Record<string, number> = { extracted: 0, meeting: 0, link: 0, total: 0 }
    for (const c of cols) {
      const idx = readIndexFor(c)
      if (!idx) continue
      for (const f of idx.files) {
        files.push({ ...f, collection: c.id, path: `${c.id}/${f.path}` })
        counts[f.mode] = (counts[f.mode] ?? 0) + 1
        counts.total += 1
      }
    }
    sendJson(res, 200, {
      collections: currentCollections().map((c) => ({ id: c.id, name: c.name })),
      files,
      counts,
    })
  }

  async function getDetail(res: ServerResponse, composite: string): Promise<void> {
    const sp = splitPath(composite)
    if (!sp) { sendJson(res, 404, { error: 'collection not found' }); return }
    const idx = readIndexFor(sp.col)
    const node = idx?.files.find((f) => f.path === sp.rel)
    if (!idx || !node) { sendJson(res, 404, { error: 'node not found' }); return }

    let content: string | null = null
    let meta: unknown = null
    let text: string | null = null
    if (node.mode === 'extracted' && node.out) {
      try { content = await fsp.readFile(path.join(sp.col.dir, node.out, 'content.md'), 'utf-8') } catch { /* */ }
      try { meta = JSON.parse(await fsp.readFile(path.join(sp.col.dir, node.out, 'meta.json'), 'utf-8')) } catch { /* */ }
    } else if (node.mode === 'link' && TEXT_EXTS.has(node.ext)) {
      const abs = originalAbs(idx, sp.rel)
      if (abs) { try { text = await fsp.readFile(abs, 'utf-8') } catch { /* */ } }
    }

    sendJson(res, 200, {
      node: { ...node, collection: sp.col.id, path: composite },
      content, meta, text,
      mime: MIME[path.extname(node.name).toLowerCase()] ?? 'application/octet-stream',
      originalUrl: `/api/original?path=${encodeURIComponent(composite)}`,
    })
  }

  async function serveOriginal(res: ServerResponse, composite: string, range?: string): Promise<void> {
    const sp = splitPath(composite)
    const idx = sp ? readIndexFor(sp.col) : null
    const abs = sp && idx ? originalAbs(idx, sp.rel) : null
    if (!abs || !isFile(abs)) { sendJson(res, 404, { error: 'original not reachable' }); return }
    const mime = MIME[path.extname(abs).toLowerCase()] ?? 'application/octet-stream'
    const size = fs.statSync(abs).size
    res.setHeader('Content-Type', mime)
    res.setHeader('Accept-Ranges', 'bytes')
    const m = range?.match(/bytes=(\d*)-(\d*)/)
    if (m) {
      const start = m[1] ? parseInt(m[1], 10) : 0
      const end = m[2] ? parseInt(m[2], 10) : size - 1
      if (start >= size || end >= size || start > end) {
        res.statusCode = 416; res.setHeader('Content-Range', `bytes */${size}`); res.end(); return
      }
      res.statusCode = 206
      res.setHeader('Content-Range', `bytes ${start}-${end}/${size}`)
      res.setHeader('Content-Length', String(end - start + 1))
      fs.createReadStream(abs, { start, end }).pipe(res)
      return
    }
    res.setHeader('Content-Length', String(size))
    fs.createReadStream(abs).pipe(res)
  }

  interface MeetingData {
    segments: Array<{ start: number; end: number; text: string; speaker: string | null }>
    frames: Array<{ file: string; url: string; time: number | null; size: number }>
    enhancedAvailable: boolean
  }

  async function meetingData(composite: string): Promise<MeetingData | null> {
    const sp = splitPath(composite)
    if (!sp) return null
    const { dir, stem } = meetusDir(sp.col, sp.rel)
    const segments: MeetingData['segments'] = []
    const whisper = path.join(dir, `${stem}.json`)
    if (fs.existsSync(whisper)) {
      try {
        const data = JSON.parse(await fsp.readFile(whisper, 'utf-8'))
        for (const s of (Array.isArray(data) ? data : data.segments ?? [])) {
          segments.push({
            start: Number(s.start ?? 0), end: Number(s.end ?? s.start ?? 0),
            text: String(s.text ?? '').trim(), speaker: s.speaker ?? null,
          })
        }
      } catch { /* none */ }
    }
    const enhanced = path.join(dir, `${stem}_enhanced.txt`)
    const times = new Map<string, number>()
    let enhancedAvailable = false
    if (fs.existsSync(enhanced)) {
      try {
        enhancedAvailable = true
        let last: number | null = null
        for (const line of (await fsp.readFile(enhanced, 'utf-8')).split('\n')) {
          const ts = line.match(/^\[(\d+):(\d+)\]/)
          if (ts) last = Number(ts[1]) * 60 + Number(ts[2])
          const fm = line.match(/Frame:\s*\S*?([^/\\\s]+\.jpg)/i)
          if (fm && last != null) times.set(fm[1], last)
        }
      } catch { /* none */ }
    }
    const frames: MeetingData['frames'] = []
    try {
      const framesDir = path.join(dir, 'frames')
      for (const file of (await fsp.readdir(framesDir)).filter((f) => f.toLowerCase().endsWith('.jpg')).sort()) {
        const fny = file.match(/_(\d+(?:\.\d+)?)s\.jpg$/i)
        let size = 0
        try { size = (await fsp.stat(path.join(framesDir, file))).size } catch { /* */ }
        frames.push({
          file,
          url: `/api/meeting/frame?path=${encodeURIComponent(composite)}&file=${encodeURIComponent(file)}`,
          time: fny ? Number(fny[1]) : times.get(file) ?? null,
          size,
        })
      }
    } catch { /* no frames */ }
    return { segments, frames, enhancedAvailable }
  }

  async function getMeeting(res: ServerResponse, composite: string): Promise<void> {
    const sp = splitPath(composite)
    const data = await meetingData(composite)
    if (!sp || !data) { sendJson(res, 404, { error: 'meeting not found' }); return }
    sendJson(res, 200, {
      path: composite,
      hasOutput: fs.existsSync(meetusDir(sp.col, sp.rel).dir),
      ...data,
      videoUrl: `/api/original?path=${encodeURIComponent(composite)}`,
    })
  }

  async function getRunShaped(res: ServerResponse, id: string): Promise<void> {
    const sp = splitPath(id)
    const data = await meetingData(id)
    if (!sp || !data) { sendJson(res, 404, { error: 'run not found' }); return }
    const { dir } = meetusDir(sp.col, sp.rel)
    let review: unknown = null
    try { review = JSON.parse(await fsp.readFile(path.join(dir, 'review.json'), 'utf-8')) } catch { /* */ }
    sendJson(res, 200, {
      id,
      manifest: { video: { name: path.basename(sp.rel) } },
      segments: data.segments,
      frames: data.frames,
      enhancedAvailable: data.enhancedAvailable,
      hasVideo: true,
      videoUrl: `/api/original?path=${encodeURIComponent(id)}`,
      review,
    })
  }

  async function saveRunReview(req: IncomingMessage, res: ServerResponse, id: string): Promise<void> {
    const sp = splitPath(id)
    if (!sp) { sendJson(res, 404, { error: 'run not found' }); return }
    const { dir } = meetusDir(sp.col, sp.rel)
    if (!fs.existsSync(dir)) { sendJson(res, 404, { error: 'no meetus output for this meeting' }); return }
    let parsed: unknown
    try { parsed = JSON.parse((await readBody(req)) || '{}') } catch { sendJson(res, 400, { error: 'invalid JSON' }); return }
    const tmp = path.join(dir, `.review.${process.pid}.tmp`)
    await fsp.writeFile(tmp, JSON.stringify(parsed, null, 2), 'utf-8')
    await fsp.rename(tmp, path.join(dir, 'review.json'))
    sendJson(res, 200, { ok: true })
  }

  function serveMeetingFrame(res: ServerResponse, composite: string, file: string): void {
    const sp = splitPath(composite)
    if (!sp) { sendJson(res, 404, { error: 'not found' }); return }
    const { dir } = meetusDir(sp.col, sp.rel)
    const safe = path.basename(file)
    const full = path.join(dir, 'frames', safe)
    if (safe !== file || !fs.existsSync(full)) { sendJson(res, 404, { error: 'frame not found' }); return }
    res.setHeader('Content-Type', 'image/jpeg')
    res.setHeader('Cache-Control', 'no-cache')
    fs.createReadStream(full).pipe(res)
  }

  async function search(res: ServerResponse, query: string, activeCsv: string | null): Promise<void> {
    const qq = query.trim().toLowerCase()
    const active = activeCsv ? new Set(activeCsv.split(',').filter(Boolean)) : null
    const cols = currentCollections().filter((c) => !active || active.has(c.id))
    let matches: string[] = []
    let bytes = 0
    if (qq) {
      for (const c of cols) {
        let cur = 0
        try { cur = fs.statSync(c.indexPath).mtimeMs } catch { /* */ }
        const cached = searchCache.get(c.id)
        if (!cached || cached.mtime !== cur) await buildSearchIndex(c)
        for (const e of searchCache.get(c.id)?.entries ?? []) {
          if (e.hay.includes(qq)) { matches.push(e.path); bytes += e.bytes }
        }
      }
    }
    sendJson(res, 200, { query: qq, matches, count: matches.length, bytes })
  }
}

function sendJson(res: ServerResponse, status: number, obj: unknown): void {
  const body = JSON.stringify(obj)
  res.statusCode = status
  res.setHeader('Content-Type', 'application/json')
  res.setHeader('Content-Length', Buffer.byteLength(body))
  res.end(body)
}

function isFile(p: string): boolean {
  try { return fs.statSync(p).isFile() } catch { return false }
}

function isDir(p: string): boolean {
  try { return fs.statSync(p).isDirectory() } catch { return false }
}

function readBody(req: IncomingMessage): Promise<string> {
  return new Promise((resolve, reject) => {
    let data = ''
    req.on('data', (c) => { data += c; if (data.length > 5_000_000) reject(new Error('body too large')) })
    req.on('end', () => resolve(data))
    req.on('error', reject)
  })
}