import path from 'node:path'
import cors from 'cors'
import express from 'express'
import helmet from 'helmet'
import { FIELDLENS_SCHEMA_VERSION, isSyncRequest, type DeviceRegistration } from '@fieldlens/contracts'
import { getAccessRequest, listAccessRequests, requestAccess, reviewAccessRequest } from './access.js'
import { authenticate, canApproveAccess, requireAccess, requireAccessApprover } from './auth.js'
import { config } from './config.js'
import { loadDeviceContext } from './context.js'
import { databaseReady, pool } from './db.js'
import { log } from './log.js'
import { FIELDLENS_MCP_OAUTH_SCOPES, handleMcpRequest } from './mcp.js'
import { runMigrations } from './migrations.js'
import { processSyncEvent } from './sync.js'

const app = express()
app.disable('x-powered-by')

const keycloakOrigin = new URL(config.issuer).origin
app.use(helmet({
  crossOriginEmbedderPolicy: false,
  contentSecurityPolicy: {
    directives: {
      defaultSrc: ["'self'"],
      scriptSrc: ["'self'"],
      styleSrc: ["'self'", "'unsafe-inline'"],
      imgSrc: ["'self'", 'data:', 'blob:'],
      mediaSrc: ["'self'", 'blob:'],
      connectSrc: ["'self'", keycloakOrigin],
      workerSrc: ["'self'", 'blob:'],
      objectSrc: ["'none'"],
      baseUri: ["'self'"],
      frameAncestors: ["'none'"],
    },
  },
}))
app.use((_req, res, next) => {
  res.setHeader('Permissions-Policy', 'camera=(self), microphone=(), geolocation=()')
  res.setHeader('Referrer-Policy', 'strict-origin-when-cross-origin')
  next()
})
const desktopOrigins = new Set([
  'tauri://localhost',
  'http://tauri.localhost',
  'https://tauri.localhost',
])

app.use(cors({
  origin(origin, callback) {
    if (!origin || origin === config.webOrigin || desktopOrigins.has(origin)) callback(null, true)
    else callback(new Error('cors_origin_rejected'))
  },
  credentials: false,
}))
app.use(express.json({ limit: '1mb' }))
app.use((req, res, next) => {
  const started = performance.now()
  res.on('finish', () => log('info', 'http_request', {
    method: req.method,
    path: req.path,
    status: res.statusCode,
    durationMs: Math.round(performance.now() - started),
  }))
  next()
})

app.get('/api/health/live', (_req, res) => {
  res.json({ status: 'live', version: process.env.FIELDLENS_VERSION ?? 'dev' })
})

function redirectDesktopDownload(res: express.Response, filename: string, baseUrl = config.desktopDownloadBaseUrl) {
  const base = baseUrl.replace(/\/$/, '')
  res.setHeader('Cache-Control', 'no-store')
  res.redirect(302, `${base}/${filename}`)
}

app.get('/downloads/fieldlens-print-windows-x64-setup.exe', (_req, res) => {
  redirectDesktopDownload(res, 'fieldlens-print-windows-x64-setup.exe')
})

app.get('/downloads/fieldlens-print-linux-x64.deb', (_req, res) => {
  redirectDesktopDownload(res, 'fieldlens-print-linux-x64.deb', config.linuxDesktopDownloadBaseUrl)
})

app.get('/downloads/install.sh', (_req, res) => {
  redirectDesktopDownload(res, 'install.sh', config.linuxDesktopDownloadBaseUrl)
})

app.get('/downloads/latest.json', (_req, res) => {
  redirectDesktopDownload(res, 'latest.json')
})

app.get('/downloads/release.json', (_req, res) => {
  redirectDesktopDownload(res, 'release.json')
})

app.get('/downloads/SHA256SUMS', (_req, res) => {
  redirectDesktopDownload(res, 'SHA256SUMS')
})

app.get('/downloads/fieldlens-print-windows-x64-setup.exe.sig', (_req, res) => {
  redirectDesktopDownload(res, 'fieldlens-print-windows-x64-setup.exe.sig')
})

app.get('/downloads/fieldlens-print-linux-x64.AppImage', (_req, res) => {
  redirectDesktopDownload(res, 'fieldlens-print-linux-x64.AppImage')
})

app.get('/downloads/fieldlens-print-linux-x64.AppImage.sig', (_req, res) => {
  redirectDesktopDownload(res, 'fieldlens-print-linux-x64.AppImage.sig')
})

// Backward-compatible aliases used by the first downloads page.
app.get('/downloads/fieldlens-print/windows-x64', (_req, res) => {
  redirectDesktopDownload(res, 'fieldlens-print-windows-x64-setup.exe')
})

app.get('/downloads/fieldlens-print/linux-x64.deb', (_req, res) => {
  redirectDesktopDownload(res, 'fieldlens-print-linux-x64.deb', config.linuxDesktopDownloadBaseUrl)
})

app.get('/api/health/ready', async (_req, res) => {
  try {
    await databaseReady()
    res.json({ status: 'ready', database: 'ready', version: process.env.FIELDLENS_VERSION ?? 'dev' })
  } catch {
    log('error', 'database_readiness_failed')
    res.status(503).json({ status: 'not-ready', database: 'unavailable' })
  }
})

const mcpResourceMetadataUrl = new URL('/.well-known/oauth-protected-resource', config.mcpResourceUrl).href
function sendMcpProtectedResourceMetadata(res: express.Response) {
  res.setHeader('Cache-Control', 'public, max-age=300')
  res.json({
    resource: config.mcpResourceUrl,
    authorization_servers: [config.issuer],
    scopes_supported: [...FIELDLENS_MCP_OAUTH_SCOPES],
    bearer_methods_supported: ['header'],
  })
}
app.get('/.well-known/oauth-protected-resource', (_req, res) => {
  sendMcpProtectedResourceMetadata(res)
})
app.get('/.well-known/oauth-protected-resource/api/mcp', (_req, res) => {
  sendMcpProtectedResourceMetadata(res)
})

app.use('/api/mcp', (_req, res, next) => {
  res.setHeader(
    'WWW-Authenticate',
    `Bearer resource_metadata="${mcpResourceMetadataUrl}", scope="${FIELDLENS_MCP_OAUTH_SCOPES.join(' ')}"`,
  )
  res.setHeader('Cache-Control', 'no-store')
  next()
}, authenticate, (_req, res, next) => {
  res.removeHeader('WWW-Authenticate')
  next()
}, requireAccess('operator'))
app.post('/api/mcp', handleMcpRequest)
app.get('/api/mcp', (_req, res) => { res.status(405).end() })
app.delete('/api/mcp', (_req, res) => { res.status(405).end() })

app.use('/api/v1', authenticate)

app.get('/api/v1/access/me', async (req, res) => {
  const request = await getAccessRequest(req.identity!.subject)
  const roles = req.identity!.roles.filter((role) => role.startsWith('fieldlens-'))
  res.json({
    status: roles.length > 0 ? 'approved' : request?.status ?? 'none',
    role: roles[0] ?? request?.approvedRole ?? null,
    canApprove: canApproveAccess(req.identity),
    username: req.identity!.username ?? null,
    email: req.identity!.email ?? null,
  })
})

app.post('/api/v1/access/request', async (req, res) => {
  const request = await requestAccess(req.identity!)
  log('info', 'access_requested', { subject: req.identity!.subject, status: request.status })
  res.status(request.status === 'approved' ? 200 : 202).json({
    status: request.status,
    role: request.approvedRole,
  })
})

app.get('/api/v1/access/requests', requireAccessApprover, async (req, res) => {
  const status = req.query.status === 'approved' || req.query.status === 'rejected'
    ? req.query.status
    : 'pending'
  const requests = await listAccessRequests(status)
  res.json({ requests })
})

app.post('/api/v1/access/requests/:subject/approve', requireAccessApprover, async (req, res) => {
  const request = await reviewAccessRequest(String(req.params.subject), 'approved', req.identity!.subject)
  if (!request) {
    res.status(404).json({ error: 'access_request_not_found' })
    return
  }
  log('info', 'access_approved', { subject: request.subject, reviewer: req.identity!.subject })
  res.json({ status: request.status, role: request.approvedRole })
})

app.post('/api/v1/access/requests/:subject/reject', requireAccessApprover, async (req, res) => {
  const request = await reviewAccessRequest(String(req.params.subject), 'rejected', req.identity!.subject)
  if (!request) {
    res.status(404).json({ error: 'access_request_not_found' })
    return
  }
  log('info', 'access_rejected', { subject: request.subject, reviewer: req.identity!.subject })
  res.json({ status: request.status })
})

app.get('/api/v1/me', requireAccess('operator'), (req, res) => {
  res.json({
    subject: req.identity!.subject,
    username: req.identity!.username,
    roles: req.identity!.roles.filter((role) => role.startsWith('fieldlens-')),
    clientId: req.identity!.clientId,
  })
})

app.get('/api/v1/stations', requireAccess('operator'), async (_req, res) => {
  const result = await pool.query(`
    SELECT s.id, s.site_id AS "siteId", s.name, s.station_type AS "stationType", s.active
    FROM stations s
    JOIN sites si ON si.id = s.site_id
    WHERE si.tenant_id = $1 AND s.active = true
    ORDER BY s.name
  `, [config.tenantId])
  res.json({ stations: result.rows })
})

app.post('/api/v1/devices/register', requireAccess('operator'), async (req, res) => {
  const body = req.body as Partial<DeviceRegistration>
  if (typeof body.installationId !== 'string' || body.schemaVersion !== FIELDLENS_SCHEMA_VERSION) {
    res.status(400).json({ error: 'invalid_device_registration' })
    return
  }

  const client = await pool.connect()
  try {
    const requestedStation = typeof body.stationId === 'string' ? body.stationId : null
    const station = await client.query<{
      id: string
      siteId: string
      name: string
      stationType: string
      active: boolean
    }>(`
      SELECT s.id, s.site_id AS "siteId", s.name, s.station_type AS "stationType", s.active
      FROM stations s
      JOIN sites si ON si.id = s.site_id
      WHERE si.tenant_id = $1 AND s.active = true
        AND ($2::uuid IS NULL OR s.id = $2::uuid)
      ORDER BY CASE WHEN $2::uuid IS NOT NULL AND s.id = $2::uuid THEN 0 ELSE 1 END, s.created_at
      LIMIT 1
    `, [config.tenantId, requestedStation])

    if (!station.rows[0]) {
      res.status(409).json({ error: 'no_active_station' })
      return
    }

    const deviceId = crypto.randomUUID()
    const result = await client.query<{ id: string }>(`
      INSERT INTO devices (id, station_id, installation_id, label, last_seen_at, app_version)
      VALUES ($1,$2,$3,$4,now(),$5)
      ON CONFLICT (installation_id) DO UPDATE SET
        station_id = EXCLUDED.station_id,
        label = COALESCE(EXCLUDED.label, devices.label),
        last_seen_at = now(),
        app_version = EXCLUDED.app_version
      RETURNING id
    `, [deviceId, station.rows[0].id, body.installationId, body.label ?? null, body.appVersion ?? null])

    log('info', 'device_registered', { deviceId: result.rows[0]!.id, stationId: station.rows[0].id })
    res.json({ id: result.rows[0]!.id, station: station.rows[0] })
  } finally {
    client.release()
  }
})

app.post('/api/v1/sync', requireAccess('operator'), async (req, res) => {
  if (!isSyncRequest(req.body)) {
    res.status(400).json({ error: 'invalid_sync_request' })
    return
  }

  const client = await pool.connect()
  try {
    const context = await loadDeviceContext(client, req.body.deviceId)
    if (!context) {
      res.status(403).json({ error: 'device_not_registered_for_tenant' })
      return
    }

    const acknowledgements = []
    for (const event of req.body.events) {
      acknowledgements.push(await processSyncEvent(client, event, context, req.identity!))
    }
    await client.query('UPDATE devices SET last_seen_at = now() WHERE id = $1', [context.deviceId])
    const accepted = acknowledgements.filter((ack) => ack.status === 'accepted').length
    const duplicate = acknowledgements.filter((ack) => ack.status === 'duplicate').length
    const rejected = acknowledgements.filter((ack) => ack.status === 'rejected').length
    log('info', 'sync_batch', { deviceId: context.deviceId, size: acknowledgements.length, accepted, duplicate, rejected })
    res.json({ schemaVersion: FIELDLENS_SCHEMA_VERSION, acknowledgements })
  } finally {
    client.release()
  }
})

app.get('/api/v1/print-captures', requireAccess('operator'), async (req, res) => {
  const requested = Number(req.query.limit ?? 50)
  const limit = Number.isFinite(requested) ? Math.max(1, Math.min(200, Math.trunc(requested))) : 50
  const result = await pool.query(`
    SELECT id, device_id AS "deviceId", source, stream_format AS "streamFormat",
           byte_count AS "byteCount", barcode_count AS "barcodeCount", forwarded,
           failure_kind AS "failureKind", app_version AS "appVersion",
           captured_at AS "capturedAt", received_at AS "receivedAt"
    FROM print_capture_diagnostics WHERE tenant_id = $1
    ORDER BY captured_at DESC LIMIT $2
  `, [config.tenantId, limit])
  res.json({ captures: result.rows })
})

app.get('/api/v1/scans', requireAccess('supervisor'), async (req, res) => {
  const limit = Math.max(1, Math.min(500, Number(req.query.limit ?? 100)))
  const result = await pool.query(`
    SELECT id, station_id AS "stationId", device_id AS "deviceId", raw_value AS "rawValue",
           format, duplicate, source, source_metadata AS "sourceMetadata",
           captured_at AS "capturedAt", received_at AS "receivedAt"
    FROM scans WHERE tenant_id = $1
    ORDER BY captured_at DESC LIMIT $2
  `, [config.tenantId, limit])
  res.json({ scans: result.rows })
})

app.get('/api/v1/pallet-sessions/:id', requireAccess('supervisor'), async (req, res) => {
  const session = await pool.query(`
    SELECT ps.* FROM pallet_sessions ps
    WHERE ps.id = $1 AND ps.tenant_id = $2
  `, [req.params.id, config.tenantId])
  if (!session.rows[0]) {
    res.status(404).json({ error: 'not_found' })
    return
  }
  const observations = await pool.query(
    'SELECT * FROM pallet_observations WHERE pallet_session_id = $1 ORDER BY carton_index',
    [req.params.id],
  )
  const exceptions = await pool.query(
    'SELECT * FROM pallet_exceptions WHERE pallet_session_id = $1 ORDER BY created_at',
    [req.params.id],
  )
  res.json({ session: session.rows[0], observations: observations.rows, exceptions: exceptions.rows })
})

app.get('/api/v1/reference/labels/:ean', requireAccess('operator'), async (req, res) => {
  const started = performance.now()
  try {
    const result = await pool.query<{ fields_json: Record<string, unknown> }>(`
      SELECT fields_json FROM reference_label_specs
      WHERE tenant_id = $1 AND ean = $2 AND active = true
      ORDER BY updated_at DESC
    `, [config.tenantId, req.params.ean])
    res.json({ rows: result.rows.map((row) => row.fields_json) })
    log('info', 'reference_lookup', {
      ean: req.params.ean,
      rows: result.rowCount,
      durationMs: Math.round(performance.now() - started),
    })
  } catch {
    log('error', 'reference_lookup_failed', {
      ean: req.params.ean,
      durationMs: Math.round(performance.now() - started),
    })
    res.status(503).json({ error: 'reference_provider_unavailable' })
  }
})

app.get('/api/v1/ops/summary', requireAccess('supervisor'), async (_req, res) => {
  const [stations, devices, scans, sessions, exceptions] = await Promise.all([
    pool.query('SELECT count(*)::int AS count FROM stations s JOIN sites si ON si.id=s.site_id WHERE si.tenant_id=$1 AND s.active=true', [config.tenantId]),
    pool.query('SELECT count(*)::int AS count, max(last_seen_at) AS last_seen FROM devices d JOIN stations s ON s.id=d.station_id JOIN sites si ON si.id=s.site_id WHERE si.tenant_id=$1', [config.tenantId]),
    pool.query("SELECT count(*)::int AS count FROM scans WHERE tenant_id=$1 AND captured_at > now() - interval '24 hours'", [config.tenantId]),
    pool.query("SELECT count(*)::int AS count FROM pallet_sessions WHERE tenant_id=$1 AND started_at > now() - interval '24 hours'", [config.tenantId]),
    pool.query('SELECT count(*)::int AS count FROM pallet_exceptions pe JOIN pallet_sessions ps ON ps.id=pe.pallet_session_id WHERE ps.tenant_id=$1', [config.tenantId]),
  ])
  res.json({
    stations: stations.rows[0],
    devices: devices.rows[0],
    scans24h: scans.rows[0],
    palletSessions24h: sessions.rows[0],
    conformityExceptions: exceptions.rows[0],
  })
})

if (config.staticDir) {
  const staticDir = path.resolve(config.staticDir)
  app.use(express.static(staticDir, {
    etag: true,
    maxAge: '1h',
    setHeaders(res, filename) {
      if (filename.endsWith('sw.js') || filename.includes('workbox-')) {
        res.setHeader('Cache-Control', 'no-cache')
      }
    },
  }))
  app.use((req, res, next) => {
    if (req.method !== 'GET' || req.path.startsWith('/api/')) return next()
    res.setHeader('Cache-Control', 'no-cache')
    res.sendFile(path.join(staticDir, 'index.html'))
  })
}

await runMigrations()

const server = app.listen(config.port, '0.0.0.0', () => {
  log('info', 'server_started', {
    port: config.port,
    environment: config.environment,
    version: process.env.FIELDLENS_VERSION ?? 'dev',
  })
})

async function shutdown(signal: string) {
  log('info', 'shutdown_started', { signal })
  server.close(async () => {
    await pool.end()
    process.exit(0)
  })
  setTimeout(() => process.exit(1), 10_000).unref()
}

process.on('SIGTERM', () => void shutdown('SIGTERM'))
process.on('SIGINT', () => void shutdown('SIGINT'))

export { app }