/**
 * Rota /api/sessions — lista e detalhe de sessões Claude Code.
 * Inclui /patterns e /stats (contrato C4-análise, Pipeline QT F4.1) — o 05
 * (stack-evaluator) consome só via API, nunca o SQLite directo.
 * Validação Zod em query params; detalhe carrega eventos via parseSessionFile.
 * @author Descomplicar® | Projecto Observabilidade (Espelho)
 */
import { Router } from 'express'
import { z } from 'zod'
import type { SessionsDb } from '../services/sessions/db.js'

const ListQuerySchema = z.object({
  days: z.coerce.number().int().min(1).max(3650).optional(),
  project: z.string().min(1).max(200).optional(),
  tool: z.string().min(1).max(100).optional(),
  skill: z.string().min(1).max(200).optional(),
  q: z.string().max(500).optional(),
  limit: z.coerce.number().int().min(1).max(200).default(50),
  offset: z.coerce.number().int().min(0).default(0),
})

const IdParamSchema = z.object({ id: z.string().min(1).max(200) })

const PatternsQuerySchema = z.object({
  week: z.string().regex(/^\d{4}-W\d{2}$/, 'Formato esperado: YYYY-Www').optional(),
  severity: z.enum(['info', 'warning', 'action']).optional(),
  key: z.string().min(1).max(200).optional(),
  days: z.coerce.number().int().min(1).max(3650).optional(),
  limit: z.coerce.number().int().min(1).max(200).default(50),
  offset: z.coerce.number().int().min(0).default(0),
})

const StatsQuerySchema = z.object({
  days: z.coerce.number().int().min(1).max(365).default(30),
})

/**
 * Router de análise (contrato C4): GET /patterns e GET /stats.
 * Montado em /api/sessions (contrato C4) e em /api (alias curto F4.1).
 */
export function createSessionsAnalysisRouter(db: SessionsDb): Router {
  const router = Router()

  router.get('/patterns', (req, res) => {
    const parsed = PatternsQuerySchema.safeParse(req.query)
    if (!parsed.success) {
      return res.status(400).json({ error: 'Invalid query', details: parsed.error.format() })
    }
    const { week, severity, key, days, limit, offset } = parsed.data
    const filters = {
      week,
      severity,
      pattern_key: key,
      sinceIso: days ? new Date(Date.now() - days * 86400_000).toISOString() : undefined,
      limit,
      offset,
    }
    const items = db.listPatterns(filters)
    const total = db.countPatterns(filters)
    return res.json({ total, week: week ?? null, items })
  })

  router.get('/stats', (req, res) => {
    const parsed = StatsQuerySchema.safeParse(req.query)
    if (!parsed.success) {
      return res.status(400).json({ error: 'Invalid query', details: parsed.error.format() })
    }
    return res.json(db.getStats(parsed.data.days))
  })

  return router
}

export function createSessionsRouter(db: SessionsDb): Router {
  const router = Router()

  // C4-análise: registado ANTES de /:id para não ser apanhado pelo param route
  router.use(createSessionsAnalysisRouter(db))

  router.get('/', (req, res) => {
    const parsed = ListQuerySchema.safeParse(req.query)
    if (!parsed.success) {
      return res.status(400).json({ error: 'Invalid query', details: parsed.error.format() })
    }
    const filters = parsed.data
    const items = db.listSessions(filters)
    const total = db.countSessions(filters)
    return res.json({ total, items })
  })

  router.get('/:id', (req, res) => {
    const parsed = IdParamSchema.safeParse(req.params)
    if (!parsed.success) {
      return res.status(400).json({ error: 'Invalid id' })
    }
    const session = db.getSession(parsed.data.id)
    if (!session) return res.status(404).json({ error: 'Session not found' })

    const events = db.getSessionEvents(parsed.data.id)
    if (events.length === 0 && session.source === 'claude') {
      return res.status(410).json({
        error: 'Session events not yet indexed',
        session_id: parsed.data.id,
      })
    }
    return res.json({ meta: session, events })
  })

  return router
}