import http from "node:http"
import { readFile } from "node:fs/promises"
import { createReadStream, existsSync } from "node:fs"
import { extname, join, normalize } from "node:path"
import mysql from "mysql2/promise"

const DB = {
  host: process.env.DB_HOST || "127.0.0.1",
  port: Number(process.env.DB_PORT || 3306),
  user: process.env.DB_USER || "photoprism",
  password: process.env.DB_PASSWORD || "",
  database: process.env.DB_NAME || "photoprism",
  connectionLimit: 4,
}

const PORT = Number(process.env.PORT || 3100)
const THUMBS = process.env.THUMBS_ROOT || "/srv/photoprism/storage/cache/thumbnails"
const PUBLIC = join(process.cwd(), "public")
const MIN_PATH = 3

const pool = mysql.createPool(DB)

const THUMB_SIZE = "1280x1024_fit"
const BIG_SIZE = "1920x1200_fit"
const thumb = (hash, size = THUMB_SIZE) => {
  if (!hash) return null
  const s = hash.toString()
  return `/thumbs/${s[0]}/${s[1]}/${s[2]}/${s}_${size}.jpg`
}

let state = null

async function load() {
  const [photos] = await pool.query(
    `SELECT p.id, p.photo_title, p.photo_year, p.photo_month, p.photo_day,
            f.file_hash, f.file_width, f.file_height
       FROM photos p
       JOIN files f ON f.photo_id = p.id AND f.file_primary = 1 AND f.file_missing = 0
      WHERE p.deleted_at IS NULL
      ORDER BY p.taken_at_local, p.id`
  )

  const byId = new Map()
  const photoOrder = []
  for (const p of photos) {
    byId.set(p.id, {
      id: p.id,
      thumb: thumb(p.file_hash),
      full: thumb(p.file_hash, BIG_SIZE),
      title: p.photo_title || "",
      date: p.photo_year
        ? `${p.photo_year}-${String(p.photo_month || 1).padStart(2, "0")}-${String(p.photo_day || 1).padStart(2, "0")}`
        : "",
      w: p.file_width || 0,
      h: p.file_height || 0,
    })
    photoOrder.push(p.id)
  }
  const rank = new Map(photoOrder.map((id, i) => [id, i]))

  const paths = new Map()
  const photoPaths = new Map()

  function addRows(rows, type, label) {
    const grouped = new Map()
    for (const r of rows) {
      if (!byId.has(r.pid)) continue
      if (!grouped.has(r.k)) grouped.set(r.k, { key: `${type}:${r.k}`, type, label, name: r.name, ids: [] })
      grouped.get(r.k).ids.push(r.pid)
    }
    for (const g of grouped.values()) {
      g.ids.sort((a, b) => rank.get(a) - rank.get(b))
      g.count = g.ids.length
      paths.set(g.key, g)
      for (const pid of g.ids) {
        if (!photoPaths.has(pid)) photoPaths.set(pid, [])
        photoPaths.get(pid).push(g)
      }
    }
  }

  const [lab] = await pool.query(
    `SELECT pl.label_id AS k, l.label_name AS name, pl.photo_id AS pid
       FROM photos_labels pl JOIN labels l ON l.id = pl.label_id`)
  addRows(lab, "label", "Labels")

  const [kw] = await pool.query(
    `SELECT pk.keyword_id AS k, kw.keyword AS name, pk.photo_id AS pid
       FROM photos_keywords pk JOIN keywords kw ON kw.id = pk.keyword_id`)
  addRows(kw, "keyword", "Keywords")

  const [cam] = await pool.query(
    `SELECT p.camera_id AS k, CONCAT(c.camera_make, ' ', c.camera_model) AS name, p.id AS pid
       FROM photos p JOIN cameras c ON c.id = p.camera_id
      WHERE p.camera_id <> 1 AND p.camera_id IS NOT NULL`)
  addRows(cam, "camera", "Cameras")

  const [len] = await pool.query(
    `SELECT p.lens_id AS k, l.lens_model AS name, p.id AS pid
       FROM photos p JOIN lenses l ON l.id = p.lens_id
      WHERE p.lens_id <> 1 AND p.lens_id IS NOT NULL`)
  addRows(len, "lens", "Lenses")

  const facets = []
  for (const type of ["label", "keyword", "camera", "lens"]) {
    const list = Array.from(paths.values())
      .filter((g) => g.type === type && g.count >= MIN_PATH)
      .sort((a, b) => b.count - a.count || a.name.localeCompare(b.name))
    for (const g of list) facets.push({ type: g.type, label: g.label, name: g.name, count: g.count, ids: g.ids })
  }

  const library = { key: "library:all", type: "library", label: "Library", name: "library", ids: photoOrder, count: photoOrder.length }
  const DIRS = ["N", "E", "S", "W"]
  const exits = new Map()
  for (const pid of photoOrder) {
    const own = (photoPaths.get(pid) || [])
      .filter((p) => p.count >= 2)
      .sort((a, b) => b.count - a.count || a.name.localeCompare(b.name) || a.type.localeCompare(b.type))
    const chosen = own.slice(0, 4)
    while (chosen.length < 4) chosen.push(library)
    const used = new Map()
    const usedNext = new Set()
    const list = []
    for (let i = 0; i < 4; i++) {
      const p = chosen[i]
      const step = used.get(p.key) || 0
      used.set(p.key, step + 1)
      const idx = p.ids.indexOf(pid)
      const cyc = p.ids
      const start = (idx + 1 + step) % cyc.length
      const walk = []
      for (let k = 0; k < 60 && walk.length < cyc.length; k++) walk.push(cyc[(start + k) % cyc.length])
      let nextId = cyc[start]
      for (const wid of walk) {
        if (wid !== pid && !usedNext.has(wid)) { nextId = wid; break }
      }
      usedNext.add(nextId)
      const wi = walk.indexOf(nextId)
      const rot = wi > 0 ? walk.slice(wi).concat(walk.slice(0, wi)) : walk
      list.push({
        dir: DIRS[i],
        path: { type: p.type, name: p.name, count: p.count },
        nextId,
        walk: rot,
      })
    }
    exits.set(pid, list)
  }

  return { builtAt: new Date().toISOString(), photos: Object.fromEntries(byId), facets, photoOrder, byId, exits }
}

async function refresh() {
  try {
    state = await load()
  } catch (err) {
    console.error("pathways: refresh failed:", err.message)
  }
}

const MIME = { ".html": "text/html; charset=utf-8", ".css": "text/css", ".js": "text/javascript", ".svg": "image/svg+xml", ".ico": "image/x-icon" }

function serveFile(res, path) {
  if (!existsSync(path)) {
    res.writeHead(404).end("not found")
    return
  }
  const type = MIME[extname(path)] || "application/octet-stream"
  const cache = path.endsWith(".html") ? "no-cache" : "max-age=300"
  res.writeHead(200, { "Content-Type": type, "Cache-Control": cache })
  createReadStream(path).pipe(res)
}

function json(res, code, data) {
  res.writeHead(code, { "Content-Type": "application/json; charset=utf-8", "Cache-Control": "no-store" })
  res.end(JSON.stringify(data))
}

async function photoConnections(id) {
  const [ph] = await pool.query(
    `SELECT p.id, p.photo_title, p.photo_year, p.photo_month, p.photo_day,
            f.file_hash, f.file_width, f.file_height
       FROM photos p
       JOIN files f ON f.photo_id = p.id AND f.file_primary = 1 AND f.file_missing = 0
      WHERE p.id = ?`,
    [id]
  )
  if (ph.length === 0) return null
  const p = ph[0]
  const conns = []

  const [labels] = await pool.query(
    `SELECT l.label_name AS name, COUNT(*) AS n
       FROM photos_labels pl JOIN labels l ON l.id = pl.label_id
      WHERE pl.photo_id = ? GROUP BY pl.label_id`,
    [id]
  )
  const [keywords] = await pool.query(
    `SELECT kw.keyword AS name, COUNT(*) AS n
       FROM photos_keywords pk JOIN keywords kw ON kw.id = pk.keyword_id
      WHERE pk.photo_id = ? GROUP BY pk.keyword_id`,
    [id]
  )
  const [camera] = await pool.query(
    `SELECT CONCAT(c.camera_make, ' ', c.camera_model) AS name, COUNT(*) AS n
       FROM photos p JOIN cameras c ON c.id = p.camera_id WHERE p.id = ?`,
    [id]
  )
  const [lens] = await pool.query(
    `SELECT l.lens_model AS name, COUNT(*) AS n
       FROM photos p JOIN lenses l ON l.id = p.lens_id WHERE p.id = ?`,
    [id]
  )

  for (const r of labels) conns.push({ type: "label", name: r.name, n: r.n })
  for (const r of keywords) conns.push({ type: "keyword", name: r.name, n: r.n })
  for (const r of camera) conns.push({ type: "camera", name: r.name, n: r.n })
  for (const r of lens) conns.push({ type: "lens", name: r.name, n: r.n })

  return {
    photo: {
      id: p.id,
      thumb: thumb(p.file_hash),
      full: thumb(p.file_hash, BIG_SIZE),
      title: p.photo_title || "",
      date: p.photo_year ? `${p.photo_year}-${String(p.photo_month || 1).padStart(2, "0")}-${String(p.photo_day || 1).padStart(2, "0")}` : "",
      w: p.file_width || 0,
      h: p.file_height || 0,
    },
    connections: conns,
  }
}

const server = http.createServer(async (req, res) => {
  const url = new URL(req.url, `http://${req.headers.host || "localhost"}`)
  const path = url.pathname

  try {
    if (path === "/api/paths") {
      if (!state) await refresh()
      return json(res, 200, { builtAt: state.builtAt, photos: state.photos, facets: state.facets })
    }
    if (path === "/api/random") {
      if (!state) await refresh()
      const id = state.photoOrder[Math.floor(Math.random() * state.photoOrder.length)]
      return json(res, 200, { photo: state.byId.get(id) })
    }
    const exitMatch = path.match(/^\/api\/exits\/(\d+)$/)
    if (exitMatch) {
      if (!state) await refresh()
      const id = Number(exitMatch[1])
      const e = state.exits.get(id)
      if (!e) return json(res, 404, { error: "not found" })
      const photos = {}
      for (const x of e) for (const wid of x.walk) {
        const ph = state.byId.get(wid)
        if (ph) photos[wid] = ph
      }
      return json(res, 200, {
        photo: state.byId.get(id),
        exits: e.map((x) => ({ dir: x.dir, path: x.path, next: state.byId.get(x.nextId), walk: x.walk })),
        photos,
      })
    }
    const photoMatch = path.match(/^\/api\/photo\/(\d+)$/)
    if (photoMatch) {
      const data = await photoConnections(Number(photoMatch[1]))
      if (!data) return json(res, 404, { error: "not found" })
      return json(res, 200, data)
    }
    if (path === "/api/health") return json(res, 200, { ok: true })

    if (path === "/" || path === "") {
      return serveFile(res, join(PUBLIC, "index.html"))
    }
    const safe = normalize(path).replace(/^(\.\.[/\\])+/, "")
    const file = join(PUBLIC, safe)
    if (file.startsWith(PUBLIC)) return serveFile(res, file)

    res.writeHead(404).end("not found")
  } catch (err) {
    console.error("pathways:", err)
    json(res, 500, { error: "internal error" })
  }
})

server.listen(PORT, "127.0.0.1", () => {
  console.log(`pathways listening on 127.0.0.1:${PORT}`)
  refresh()
})
setInterval(refresh, 30 * 60 * 1000).unref()