const { spawn } = require("child_process")
const express = require("express")
const fs = require("fs")
const cors = require("cors")
const path = require("path")
const axios = require("axios")

const PORT = 7860
const app = express()
const baseOutputDir = path.join(__dirname, "hls_output")
const publicDir = path.join(__dirname, "public")
const transitionVideo = "https://files.catbox.moe/hvl1cv.mp4"
const watermarkText = "AnitakuX"
const channelsFile = path.join(__dirname, "channels.json")

app.use(cors())

// Enhanced CORS configuration
app.use(
  cors({
    origin: ["http://localhost:7860", "http://127.0.0.1:7860", "http://localhost:3000"],
    credentials: true,
  }),
)

// Add headers for better streaming
app.use((req, res, next) => {
  res.header("Access-Control-Allow-Origin", "*")
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept")
  res.header("Cache-Control", "no-cache, no-store, must-revalidate")
  res.header("Pragma", "no-cache")
  res.header("Expires", "0")
  next()
})

// Load channels from JSON file
let channels = {}
try {
  channels = JSON.parse(fs.readFileSync(channelsFile))
} catch (err) {
  channels = {
    channel1: {
      name: "Anitaku TV 1",
      playlist: [
        { title: "Lazarus", start: 1, end: 12 },
        { title: "Erased", start: 1, end: 12 },
      ],
      schedule: [],
    },
    channel2: {
      name: "Anitaku TV 2",
      playlist: [{ title: "Eminence in Shadow", start: 1, end: 20 }],
      schedule: [],
    },
    channel3: {
      name: "Anitaku TV 3",
      playlist: [{ title: "Attack on Titan", start: 1, end: 25 }],
      schedule: [],
    },
    channel4: {
      name: "Anitaku TV 4",
      playlist: [{ title: "Demon Slayer", start: 1, end: 26 }],
      schedule: [],
    },
    channel5: {
      name: "Anitaku TV 5",
      playlist: [{ title: "Chained Soldier", start: 1, end: 11 }],
      schedule: [],
    },
    channel6: {
      name: "Anitaku TV 6",
      playlist: [{ title: "Solo Leveling", start: 1, end: 13 }],
      schedule: [],
    },
  }
  fs.writeFileSync(channelsFile, JSON.stringify(channels, null, 2))
}

// Serve static files from public directory
app.use(express.static(publicDir))
app.use(express.json())

// Helper function to format time in WAT (UTC+1)
function formatWATTime(date) {
  const watOffset = 1 * 60 * 60 * 1000
  const watDate = new Date(date.getTime() + watOffset)
  return watDate.toLocaleTimeString("en-US", {
    hour12: false,
    hour: "2-digit",
    minute: "2-digit",
  })
}

// Get video duration using ffprobe
async function getVideoDuration(url) {
  return new Promise((resolve) => {
    const ffprobe = spawn("ffprobe", ["-v", "quiet", "-print_format", "json", "-show_format", url])

    let output = ""
    ffprobe.stdout.on("data", (data) => {
      output += data.toString()
    })

    ffprobe.on("close", (code) => {
      try {
        if (code === 0) {
          const info = JSON.parse(output)
          const duration = Number.parseFloat(info.format.duration)
          resolve(duration * 1000)
        } else {
          console.log(`Failed to get duration for ${url}, using default 22 minutes`)
          resolve(22 * 60 * 1000)
        }
      } catch (err) {
        console.log(`Error parsing duration for ${url}, using default 22 minutes`)
        resolve(22 * 60 * 1000)
      }
    })

    ffprobe.on("error", () => {
      console.log(`ffprobe error for ${url}, using default 22 minutes`)
      resolve(22 * 60 * 1000)
    })
  })
}

// Generate schedule for a channel
async function generateSchedule(channelConfig) {
  const schedule = []
  let currentTime = new Date()

  for (const anime of channelConfig.playlist) {
    for (let ep = anime.start; ep <= anime.end; ep++) {
      const startTime = new Date(currentTime)

      let duration = 22 * 60 * 1000
      try {
        const mp4 = await getEpisodeMp4(anime.title, ep)
        if (mp4) {
          duration = await getVideoDuration(mp4)
        }
      } catch (err) {
        console.log(`Could not get duration for ${anime.title} Episode ${ep}, using default`)
      }

      const totalDuration = duration + 3 * 60 * 1000
      const endTime = new Date(currentTime.getTime() + totalDuration)

      schedule.push({
        title: `${anime.title} Episode ${ep}`,
        startTime: formatWATTime(startTime),
        endTime: formatWATTime(endTime),
        duration: Math.round(duration / (60 * 1000)),
      })

      currentTime = new Date(endTime.getTime() + 1000)
    }
  }
  return schedule
}

function wait(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms))
}

async function getEpisodeMp4(anime, ep) {
  const url = `https://txtorg-anihx.hf.space/api/episode?anime=${encodeURIComponent(anime)}&ep=${ep}`
  const data = await axios
    .get(url)
    .then((r) => r.data)
    .catch(() => null)
  const dl = data?.links?.sub?.["360p_download"]
  if (!dl) return null
  return await axios
    .get(`https://txtorg-anihx.hf.space/resolvex?url=${dl}`)
    .then((r) => r.data?.mp4Link)
    .catch(() => null)
}

// Enhanced FFmpeg function with better streaming parameters
function startFFmpeg(channelId, inputUrl, outputDir, onExit, isLoop = false, isTransition = false) {
  const baseArgs = ["-re"]

  if (isLoop) {
    baseArgs.push("-stream_loop", "-1")
  }

  // Enhanced streaming parameters for seamless playback
  const args = [
    ...baseArgs,
    "-i",
    inputUrl,
    "-vf",
    `drawtext=text='${watermarkText}':fontcolor=white:fontsize=24:x=w-tw-20:y=20`,
    "-c:v",
    "libx264",
    "-preset",
    "veryfast", // Balance between speed and quality
    "-tune",
    "zerolatency",
    "-profile:v",
    "baseline",
    "-level",
    "3.0",
    "-c:a",
    "aac",
    "-b:a",
    "128k",
    "-ar",
    "44100",
    "-g",
    "50", // Increased GOP for stability
    "-keyint_min",
    "25",
    "-sc_threshold",
    "0",
    "-f",
    "hls",
    "-hls_time",
    "4", // Increased segment time for stability
    "-hls_list_size",
    "6", // Reasonable playlist size
    "-hls_flags",
    "delete_segments+program_date_time",
    "-hls_segment_type",
    "mpegts",
    "-hls_segment_filename",
    path.join(outputDir, "segment_%03d.ts"),
    "-hls_allow_cache",
    "1",
    "-hls_base_url",
    `http://localhost:7860/hls/${channelId}/`,
    path.join(outputDir, "stream.m3u8"),
  ]

  console.log(
    `🔴 [${channelId}] Starting FFmpeg for ${inputUrl}${isLoop ? " (LOOP)" : ""}${isTransition ? " (TRANSITION)" : ""}`,
  )
  const proc = spawn("ffmpeg", args)

  proc.stderr.on("data", (d) => {
    const output = d.toString()
    // Only log important messages to reduce noise
    if (output.includes("error") || output.includes("Error") || output.includes("failed")) {
      console.error(`[FFMPEG ${channelId}] ${output}`)
    }
  })

  proc.on("exit", (code) => {
    console.log(`[FFMPEG ${channelId}] Process exited with code ${code}`)
    if (onExit) onExit(code)
  })

  return proc
}

function setupChannel(channelId, channelConfig) {
  const state = {
    index: 0,
    ep: channelConfig.playlist[0].start,
    isTransition: false,
    process: null,
    anime: channelConfig.playlist[0].title,
    currentEp: 1,
    nextEpisodeReady: false,
    nextEpisodeUrl: null,
    transitionStartTime: null,
    preloadQueue: [], // Queue for preloaded episodes
    isPreloading: false,
  }

  const channelOutput = path.join(baseOutputDir, channelId)
  if (fs.existsSync(channelOutput)) fs.rmSync(channelOutput, { recursive: true, force: true })
  fs.mkdirSync(channelOutput, { recursive: true })

  // Generate initial schedule
  generateSchedule(channelConfig).then((schedule) => {
    channelConfig.schedule = schedule
  })

  // Enhanced preloading system
  async function preloadNextEpisodes() {
    if (state.isPreloading) return
    state.isPreloading = true

    try {
      // Preload next 2-3 episodes
      const episodesToPreload = 3
      const currentEntry = channelConfig.playlist[state.index]

      for (let i = 1; i <= episodesToPreload; i++) {
        let nextEp = state.ep + i
        let nextIndex = state.index

        // Handle playlist wraparound
        while (nextEp > channelConfig.playlist[nextIndex].end) {
          nextEp = nextEp - channelConfig.playlist[nextIndex].end + channelConfig.playlist[nextIndex].start - 1
          nextIndex++
          if (nextIndex >= channelConfig.playlist.length) {
            nextIndex = 0
            nextEp = channelConfig.playlist[nextIndex].start + (nextEp - 1)
          }
        }

        const nextEntry = channelConfig.playlist[nextIndex]
        const cacheKey = `${nextEntry.title}_${nextEp}`

        // Skip if already in queue
        if (state.preloadQueue.find((item) => item.key === cacheKey)) continue

        console.log(`[${channelId}] 🔄 Preloading: ${nextEntry.title} Episode ${nextEp}`)

        try {
          const nextUrl = await getEpisodeMp4(nextEntry.title, nextEp)
          if (nextUrl) {
            state.preloadQueue.push({
              key: cacheKey,
              url: nextUrl,
              title: nextEntry.title,
              episode: nextEp,
              timestamp: Date.now(),
            })
            console.log(`[${channelId}] ✅ Preloaded: ${nextEntry.title} Episode ${nextEp}`)
          }
        } catch (err) {
          console.log(`[${channelId}] ❌ Failed to preload: ${nextEntry.title} Episode ${nextEp}`)
        }
      }

      // Clean old preloaded episodes (keep only recent ones)
      const maxAge = 10 * 60 * 1000 // 10 minutes
      state.preloadQueue = state.preloadQueue.filter((item) => Date.now() - item.timestamp < maxAge)
    } finally {
      state.isPreloading = false
    }
  }

  // Get next episode URL from preload queue or fetch fresh
  async function getNextEpisodeUrl() {
    const currentEntry = channelConfig.playlist[state.index]
    let nextEp = state.ep + 1
    let nextIndex = state.index

    if (nextEp > currentEntry.end) {
      nextIndex++
      if (nextIndex >= channelConfig.playlist.length) nextIndex = 0
      nextEp = channelConfig.playlist[nextIndex].start
    }

    const nextEntry = channelConfig.playlist[nextIndex]
    const cacheKey = `${nextEntry.title}_${nextEp}`

    // Check preload queue first
    const preloaded = state.preloadQueue.find((item) => item.key === cacheKey)
    if (preloaded) {
      console.log(`[${channelId}] 🚀 Using preloaded: ${nextEntry.title} Episode ${nextEp}`)
      return preloaded.url
    }

    // Fallback to fresh fetch
    console.log(`[${channelId}] 📡 Fetching fresh: ${nextEntry.title} Episode ${nextEp}`)
    return await getEpisodeMp4(nextEntry.title, nextEp)
  }

  async function seamlessTransition() {
    console.log(`[${channelId}] 🔄 Starting seamless transition...`)

    // Get next episode URL with retry logic
    let nextUrl = null
    let retryCount = 0
    const maxRetries = 3

    while (!nextUrl && retryCount < maxRetries) {
      try {
        nextUrl = await getNextEpisodeUrl()
        if (nextUrl) break
      } catch (error) {
        console.log(`[${channelId}] ❌ Retry ${retryCount + 1}/${maxRetries} failed:`, error.message)
      }
      retryCount++
      if (retryCount < maxRetries) {
        await wait(2000 * retryCount) // Exponential backoff
      }
    }

    if (nextUrl) {
      console.log(`[${channelId}] ⚡ Quick transition to next episode`)

      // Kill current process gracefully
      if (state.process) {
        state.process.kill("SIGTERM")
        await wait(1000) // Wait for graceful shutdown
      }

      // Move to next episode
      const currentEntry = channelConfig.playlist[state.index]
      state.ep++
      if (state.ep > currentEntry.end) {
        state.index++
        if (state.index >= channelConfig.playlist.length) state.index = 0
        state.ep = channelConfig.playlist[state.index].start
      }

      state.anime = channelConfig.playlist[state.index].title
      state.currentEp = state.ep
      state.isTransition = false

      // Start next episode with error handling
      try {
        state.process = startFFmpeg(channelId, nextUrl, channelOutput, async (code) => {
          console.log(`[${channelId}] ✅ Finished: ${state.anime} Ep${state.ep} (exit code: ${code})`)
          preloadNextEpisodes()
          await wait(1000) // Brief pause between episodes
          seamlessTransition()
        })
      } catch (error) {
        console.log(`[${channelId}] ❌ Failed to start next episode:`, error.message)
        // Fallback to transition video
        startTransitionFallback()
      }
    } else {
      startTransitionFallback()
    }
  }

  // Fallback transition function
  function startTransitionFallback() {
    console.log(`[${channelId}] 📺 Using transition video fallback`)

    state.isTransition = true
    state.transitionStartTime = Date.now()

    state.process = startFFmpeg(
      channelId,
      transitionVideo,
      channelOutput,
      () => {
        // Transition ended, try again
      },
      true,
      true,
    )

    // Monitor transition with timeout
    const transitionTimeout = setTimeout(async () => {
      console.log(`[${channelId}] ⏰ Transition timeout, moving to next episode`)

      if (state.process) {
        state.process.kill("SIGTERM")
      }

      // Move to next episode
      const currentEntry = channelConfig.playlist[state.index]
      state.ep++
      if (state.ep > currentEntry.end) {
        state.index++
        if (state.index >= channelConfig.playlist.length) state.index = 0
        state.ep = channelConfig.playlist[state.index].start
      }

      await wait(2000)
      seamlessTransition()
    }, 30000) // 30 second timeout

    // Clear timeout if transition ends naturally
    state.transitionTimeout = transitionTimeout
  }

  async function startChannel() {
    console.log(`[${channelId}] 🚀 Starting channel...`)

    // Start preloading episodes
    preloadNextEpisodes()

    // Start with first episode
    const entry = channelConfig.playlist[state.index]
    state.anime = entry.title
    state.currentEp = state.ep

    const mp4 = await getEpisodeMp4(entry.title, state.ep)
    if (!mp4) {
      console.log(`[${channelId}] ❌ First episode not found, starting with transition`)
      state.isTransition = true
      state.transitionStartTime = Date.now()

      state.process = startFFmpeg(
        channelId,
        transitionVideo,
        channelOutput,
        () => {
          seamlessTransition()
        },
        true,
        true,
      )
      return
    }

    state.process = startFFmpeg(channelId, mp4, channelOutput, async (code) => {
      console.log(`[${channelId}] ✅ Finished: ${entry.title} Ep${state.ep}`)
      seamlessTransition()
    })
  }

  // Start the channel
  startChannel()

  // Serve stream
  app.use(`/hls/${channelId}`, express.static(channelOutput))
}

// Health check endpoint
app.get("/api/health", (req, res) => {
  res.json({
    status: "ok",
    timestamp: new Date().toISOString(),
    channels: Object.keys(channels),
  })
})

// API Routes
app.post("/api/add-anime", async (req, res) => {
  const { channelId, title, start, end } = req.body
  if (!channels[channelId]) {
    return res.status(400).json({ error: "Invalid channel ID" })
  }
  channels[channelId].playlist.push({ title, start: Number.parseInt(start), end: Number.parseInt(end) })
  channels[channelId].schedule = await generateSchedule(channels[channelId])
  fs.writeFileSync(channelsFile, JSON.stringify(channels, null, 2))
  res.json({ success: true })
})

app.get("/watch/:channelId", (req, res) => {
  const filePath = path.join(publicDir, "channel.html")
  res.sendFile(filePath)
})

app.get("/api/schedule/:channelId", (req, res) => {
  const channelId = req.params.channelId
  if (!channels[channelId]) {
    return res.status(400).json({ error: "Invalid channel ID" })
  }
  res.json(channels[channelId].schedule)
})

app.get("/api/current/:channelId", (req, res) => {
  const channelId = req.params.channelId
  if (!channels[channelId]) {
    return res.status(400).json({ error: "Invalid channel ID" })
  }

  res.json({
    channelName: channels[channelId].name,
    status: "live",
  })
})

// Launch all channels
for (const [id, config] of Object.entries(channels)) {
  setupChannel(id, config)
}

// Create public directory if it doesn't exist
if (!fs.existsSync(publicDir)) {
  fs.mkdirSync(publicDir, { recursive: true })
}

app.listen(PORT, () => {
  console.log(`🚀 Server running on http://localhost:${PORT}`)
  console.log(`🔗 Channels:`)
  Object.keys(channels).forEach((id) => {
    console.log(`- http://localhost:${PORT}/watch/${id}`)
  })
  console.log(`- http://localhost:${PORT}/add-anime`)
})