import { readFile } from 'node:fs/promises'
import path from 'node:path'
import { writeFile } from '../atomic-write.js'
import { requireAdminAuth } from '../auth.js'
import { state } from '../state.js'
import { DATA_DIR } from '../config.js'
import { scriptKey, scriptEpisodeNumber } from '../episode-script-keys.js'
import { fetchAllEpisodes } from './episodes.js'

const WORKFLOW_FILE = path.join(DATA_DIR, 'podcast-workflow.json')

const STEPS = ['readScript', 'record', 'edit', 'upload']

async function load() {
  try {
    const data = JSON.parse(await readFile(WORKFLOW_FILE, 'utf8'))
    return { planned: Array.isArray(data.planned) ? data.planned : [], items: data.items ?? {}, laneOverrides: data.laneOverrides ?? {} }
  } catch {
    return { planned: [], items: {}, laneOverrides: {} }
  }
}

const save = data => writeFile(WORKFLOW_FILE, JSON.stringify(data, null, 2), 'utf8')

function emptyState() {
  return {
    steps: Object.fromEntries(STEPS.map(s => [s, null])),
    notes: '',
  }
}

function laneFor(season) {
  const content = state.cachedSiteContent ?? {}
  const s = String(season ?? '')
  if (s && s === String(content.seriesSeason ?? '')) return 'A'
  if (s && s === String(content.secondSeries?.season ?? '')) return 'B'
  return 'other'
}

const normTitle = t => String(t ?? '').toLowerCase().replace(/[^a-z0-9]+/g, ' ').trim()
const plannedKey = p => p.key ?? scriptKey(p.season, p.episodeNumber)

function toIsoDate(pubDate) {
  const d = new Date(pubDate)
  return Number.isNaN(d.getTime()) ? '' : d.toISOString().slice(0, 10)
}

export function register(app) {
  app.get('/api/admin/podcast-workflow', requireAdminAuth, async (_req, res) => {
    const wf = await load()
    let feed = []
    let feedOk = true
    try {
      feed = await fetchAllEpisodes()
    } catch {
      feedOk = false
    }

    const byKey = new Map()
    const upsert = (key, patch) => byKey.set(key, { ...(byKey.get(key) ?? {}), key, ...patch })

    for (const [key, entry] of Object.entries(state.episodeScripts ?? {})) {
      upsert(key, {
        season: entry.season ?? '',
        episodeNumber: scriptEpisodeNumber(key, entry),
        title: entry.title ?? '',
        hasScript: true,
      })
    }
    for (const p of wf.planned) {
      const key = plannedKey(p)
      const prev = byKey.get(key)
      upsert(key, { season: p.season, episodeNumber: p.episodeNumber, title: prev?.title || p.title || '', planned: true, plannedLane: p.lane })
    }
    for (const item of feed) {
      const hasNum = /^\d+$/.test(item.episode)
      let key
      if (item.season && hasNum) {
        key = scriptKey(item.season, item.episode)
      } else {
        // No season in the feed: pair with a script/planned episode of the same title, else keep it on its own.
        const t = normTitle(item.title)
        const match = [...byKey.values()].find(e => !e.released && normTitle(e.title) === t)
        key = match ? match.key : `t:${t}`
      }
      const prev = byKey.get(key)
      upsert(key, {
        season: item.season || prev?.season || '',
        episodeNumber: hasNum ? item.episode : (prev?.episodeNumber ?? ''),
        title: item.title || prev?.title || '',
        released: true,
        releaseDate: toIsoDate(item.pubDate),
        spotifyUrl: item.link || '',
      })
    }

    const items = [...byKey.values()].map(e => ({
      ...e,
      lane: wf.laneOverrides[e.key] ?? e.plannedLane ?? laneFor(e.season),
      laneOverride: wf.laneOverrides[e.key] ?? '',
      released: Boolean(e.released),
      state: { ...emptyState(), ...(wf.items[e.key] ?? {}) },
    }))
    items.sort((a, b) => (Number(a.season) || 0) - (Number(b.season) || 0) || (Number(a.episodeNumber) || 0) - (Number(b.episodeNumber) || 0))
    res.json({ items, feedOk })
  })

  app.post('/api/admin/podcast-workflow/planned', requireAdminAuth, async (req, res) => {
    const season = /^\d+$/.test(String(req.body?.season ?? '')) ? String(req.body.season) : ''
    const episodeNumber = String(req.body?.episodeNumber ?? '').trim()
    const title = typeof req.body?.title === 'string' ? req.body.title.trim().slice(0, 160) : ''
    if (!/^\d+$/.test(episodeNumber)) {
      res.status(400).json({ message: 'Episode number must be a whole number.' })
      return
    }
    const lane = ['A', 'B'].includes(req.body?.lane) ? req.body.lane : 'other'
    const wf = await load()
    // Without a season number the key must still be unique per lane.
    const key = season ? scriptKey(season, episodeNumber) : `${lane}-p${episodeNumber}`
    if (!wf.planned.some(p => plannedKey(p) === key)) {
      wf.planned.push({ key, season, episodeNumber, title, lane })
      await save(wf)
    }
    res.json({ ok: true, key })
  })

  app.delete('/api/admin/podcast-workflow/planned/:key', requireAdminAuth, async (req, res) => {
    const wf = await load()
    wf.planned = wf.planned.filter(p => plannedKey(p) !== req.params.key)
    delete wf.items[req.params.key]
    delete wf.laneOverrides[req.params.key]
    await save(wf)
    res.json({ ok: true })
  })

  // Assign an episode to a lane by hand ('auto' clears the override and goes back to season matching).
  app.put('/api/admin/podcast-workflow/:key/lane', requireAdminAuth, async (req, res) => {
    const lane = req.body?.lane
    if (!['A', 'B', 'other', 'auto'].includes(lane)) {
      res.status(400).json({ message: 'Lane must be A, B, other or auto.' })
      return
    }
    const wf = await load()
    if (lane === 'auto') delete wf.laneOverrides[req.params.key]
    else wf.laneOverrides[req.params.key] = lane
    await save(wf)
    res.json({ ok: true })
  })

  app.put('/api/admin/podcast-workflow/:key', requireAdminAuth, async (req, res) => {
    const { key } = req.params
    const wf = await load()
    const prev = { ...emptyState(), ...(wf.items[key] ?? {}) }
    const next = { ...prev, steps: { ...prev.steps } }
    const body = req.body ?? {}
    if (body.steps && typeof body.steps === 'object') {
      for (const s of STEPS) {
        if (typeof body.steps[s] === 'boolean') {
          next.steps[s] = body.steps[s] ? (prev.steps[s] ?? new Date().toISOString()) : null
        }
      }
    }
    if (typeof body.notes === 'string') next.notes = body.notes.slice(0, 5000)
    wf.items[key] = next
    await save(wf)
    res.json({ ok: true, state: next })
  })
}