require('dotenv').config();
const express = require('express');
const axios = require('axios');

const app = express();
const port = process.env.PORT || 3000;

// Log all incoming requests
app.use((req, res, next) => {
    console.log(`[Proxy Log] ${new Date().toISOString()} - ${req.method} ${req.url} - IP: ${req.ip}`);
    next();
});

// Parse channels from .env
// Expected format: CHANNELS=id1:Name1,id2:Name2
const parseChannels = () => {
    const channelsString = process.env.CHANNELS || '';
    if (!channelsString) return [];
    
    return channelsString.split(',').map(ch => {
        const [id, ...nameParts] = ch.split(':');
        return { id: id.trim(), name: nameParts.join(':').trim() };
    }).filter(ch => ch.id && ch.name);
};

// Helper: build request headers with optional Naver auth cookies
const buildHeaders = () => {
    const headers = {
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36'
    };
    const cookies = [];
    if (process.env.NID_AUT) cookies.push(`NID_AUT=${process.env.NID_AUT}`);
    if (process.env.NID_SES) cookies.push(`NID_SES=${process.env.NID_SES}`);
    if (cookies.length > 0) {
        headers['Cookie'] = cookies.join('; ');
    }
    return headers;
};

// Helper: fetch live-detail for a single channel
const fetchLiveDetail = async (channelId) => {
    const response = await axios.get(
        `https://api.chzzk.naver.com/service/v3/channels/${channelId}/live-detail`,
        { headers: buildHeaders() }
    );
    return response.data && response.data.content;
};

// Static playlist — always contains all channels
app.get('/playlist.m3u', (req, res) => {
    const channels = parseChannels();
    const host = req.get('host');
    const protocol = req.protocol;
    
    let m3u = "#EXTM3U\n";
    
    channels.forEach(ch => {
        m3u += `#EXTINF:-1 tvg-id="${ch.id}" tvg-name="${ch.name}" group-title="Chzzk",${ch.name}\n`;
        m3u += `${protocol}://${host}/stream/${ch.id}\n`;
    });
    
    res.header('Content-Type', 'application/vnd.apple.mpegurl');
    res.send(m3u);
});

// Dynamic live-only playlist — only includes channels currently broadcasting.
// To prevent Jellyfin from throwing a "Save TV provider" error when no channels are live,
// we serve a placeholder channel "No Live Streams" if the list is empty.
app.get('/playlist-live.m3u', async (req, res) => {
    const channels = parseChannels();
    const host = req.get('host');
    const protocol = req.protocol;

    const results = await Promise.allSettled(
        channels.map(async (ch) => {
            try {
                const content = await fetchLiveDetail(ch.id);
                return { ch, content };
            } catch {
                return { ch, content: null };
            }
        })
    );

    let m3u = "#EXTM3U\n";
    let liveCount = 0;

    results.forEach(r => {
        if (r.status !== 'fulfilled') return;
        const { ch, content } = r.value;
        // Only include the channel if it is actively live (OPEN status)
        if (!content || content.status !== 'OPEN') return;

        const title = content.liveTitle ? `${ch.name} — ${content.liveTitle}` : ch.name;
        const logo  = (content.channel && content.channel.channelImageUrl) || '';

        m3u += `#EXTINF:-1 tvg-id="${ch.id}" tvg-name="${ch.name}" tvg-logo="${logo}" group-title="Chzzk Live",${title}\n`;
        m3u += `${protocol}://${host}/stream/${ch.id}\n`;
        liveCount++;
    });

    if (liveCount === 0) {
        m3u += `#EXTINF:-1 tvg-id="offline" tvg-name="No Live Streams" group-title="Chzzk Live",No Live Streams\n`;
        m3u += `${protocol}://${host}/offline\n`;
    }

    res.header('Content-Type', 'application/vnd.apple.mpegurl');
    res.send(m3u);
});

app.get('/offline', (req, res) => {
    res.status(404).send('No streams are currently live.');
});

// Schedule endpoint — returns live status for all configured channels as JSON
app.get('/schedule', async (req, res) => {
    const channels = parseChannels();
    if (channels.length === 0) {
        return res.json({ channels: [], fetchedAt: new Date().toISOString() });
    }

    const results = await Promise.allSettled(
        channels.map(async (ch) => {
            try {
                const content = await fetchLiveDetail(ch.id);
                if (!content) {
                    return { id: ch.id, name: ch.name, status: 'OFFLINE' };
                }
                return {
                    id: ch.id,
                    name: ch.name,
                    status: content.status || 'UNKNOWN',
                    liveTitle: content.liveTitle || null,
                    liveCategory: content.liveCategoryValue || content.liveCategory || null,
                    openDate: content.openDate || null,
                    concurrentUserCount: content.concurrentUserCount || 0,
                    channelImageUrl: content.channel && content.channel.channelImageUrl || null,
                    liveImageUrl: content.liveImageUrl || null,
                };
            } catch {
                return { id: ch.id, name: ch.name, status: 'ERROR' };
            }
        })
    );

    const schedule = results.map(r => r.status === 'fulfilled' ? r.value : r.reason);
    res.json({ channels: schedule, fetchedAt: new Date().toISOString() });
});

// EPG endpoint — generates XMLTV-format guide data for Jellyfin
app.get('/epg.xml', async (req, res) => {
    const channels = parseChannels();
    const results = await Promise.allSettled(
        channels.map(async (ch) => {
            try {
                const content = await fetchLiveDetail(ch.id);
                return { ch, content };
            } catch {
                return { ch, content: null };
            }
        })
    );

    const escapeXml = (str) => {
        if (!str) return '';
        return str.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;')
                  .replace(/"/g, '&quot;').replace(/'/g, '&apos;');
    };

    let xml = '<?xml version="1.0" encoding="UTF-8"?>\n';
    xml += '<!DOCTYPE tv SYSTEM "xmltv.dtd">\n';
    xml += '<tv generator-info-name="czzk-stream">\n';

    // Channel definitions
    channels.forEach(ch => {
        xml += `  <channel id="${escapeXml(ch.id)}">\n`;
        xml += `    <display-name>${escapeXml(ch.name)}</display-name>\n`;
        xml += `  </channel>\n`;
    });

    // Programme entries — live channels show stream info, offline show "Off Air"
    const now = new Date();
    const pad = n => String(n).padStart(2, '0');
    const toXmltvDate = (d) =>
        `${d.getFullYear()}${pad(d.getMonth()+1)}${pad(d.getDate())}${pad(d.getHours())}${pad(d.getMinutes())}${pad(d.getSeconds())} +0000`;

    // Start of today (UTC) and end of today for Off Air block
    const dayStart = new Date(Date.UTC(now.getUTCFullYear(), now.getUTCMonth(), now.getUTCDate()));
    const dayEnd   = new Date(dayStart.getTime() + 24 * 60 * 60 * 1000);

    results.forEach(r => {
        if (r.status !== 'fulfilled') return;
        const { ch, content } = r.value;
        const isLive = content && content.status === 'OPEN';

        if (isLive) {
            const openDate = content.openDate
                ? content.openDate.replace(/[-: ]/g, '').substring(0, 14) + ' +0900'
                : toXmltvDate(now);
            const endDate = content.openDate
                ? (() => {
                    const d = new Date(content.openDate);
                    d.setHours(d.getHours() + 6);
                    return `${d.getFullYear()}${pad(d.getMonth()+1)}${pad(d.getDate())}${pad(d.getHours())}${pad(d.getMinutes())}${pad(d.getSeconds())} +0900`;
                  })()
                : toXmltvDate(dayEnd);

            xml += `  <programme start="${openDate}" stop="${endDate}" channel="${escapeXml(ch.id)}">\n`;
            xml += `    <title>${escapeXml(content.liveTitle || ch.name)}</title>\n`;
            if (content.liveCategoryValue || content.liveCategory) {
                xml += `    <category>${escapeXml(content.liveCategoryValue || content.liveCategory)}</category>\n`;
            }
            if (content.liveImageUrl) {
                const iconUrl = content.liveImageUrl.replace('{type}', '720');
                xml += `    <icon src="${escapeXml(iconUrl)}" />\n`;
            }
            xml += `  </programme>\n`;
        } else {
            // Offline — fill today with an "Off Air" block
            xml += `  <programme start="${toXmltvDate(dayStart)}" stop="${toXmltvDate(dayEnd)}" channel="${escapeXml(ch.id)}">\n`;
            xml += `    <title>Off Air</title>\n`;
            xml += `    <desc>${escapeXml(ch.name)} is not currently live.</desc>\n`;
            xml += `  </programme>\n`;
        }
    });

    xml += '</tv>\n';
    res.header('Content-Type', 'application/xml');
    res.send(xml);
});

// Helper: parse, filter, and verify playability of variants from the master playlist.
// Keeps the stream alive even if 1080p (or other qualities) return 403 Forbidden due to cookie issues.
const filterMasterPlaylist = async (m3u8Data, m3u8Url) => {
    try {
        const lines = m3u8Data.split('\n');
        const variants = [];
        let currentHeaders = [];

        for (let i = 0; i < lines.length; i++) {
            const line = lines[i].trim();
            if (!line) continue;

            if (line.startsWith('#')) {
                if (line.startsWith('#EXT-X-STREAM-INF')) {
                    currentHeaders.push(line);
                } else if (line.startsWith('#EXTM3U') || line.startsWith('#EXT-X-VERSION') || line.startsWith('#EXT-X-INDEPENDENT-SEGMENTS')) {
                    // Skip global headers as we add them manually
                } else {
                    currentHeaders.push(line);
                }
            } else {
                let uri = line;
                if (!uri.startsWith('http')) {
                    uri = new URL(uri, m3u8Url).toString();
                }
                variants.push({
                    headers: currentHeaders,
                    uri: uri
                });
                currentHeaders = [];
            }
        }

        if (variants.length === 0) return m3u8Data;

        // Test playability of each variant in parallel
        const checkedVariants = await Promise.all(
            variants.map(async (v) => {
                try {
                    await axios.get(v.uri, {
                        headers: buildHeaders(),
                        timeout: 1500,
                        responseType: 'stream'
                    });
                    return { ...v, playable: true };
                } catch (err) {
                    console.log(`[Proxy] Quality variant not playable: ${v.uri} (status: ${err.response?.status || 'error'})`);
                    return { ...v, playable: false };
                }
            })
        );

        const playableVariants = checkedVariants.filter(v => v.playable);
        const finalVariants = playableVariants.length > 0 ? playableVariants : variants;

        let output = '#EXTM3U\n#EXT-X-VERSION:7\n#EXT-X-INDEPENDENT-SEGMENTS\n';
        finalVariants.forEach(v => {
            v.headers.forEach(h => {
                output += h + '\n';
            });
            output += v.uri + '\n';
        });

        return output;
    } catch (error) {
        console.error('Error filtering master playlist:', error.message);
        return m3u8Data;
    }
};

// Helper: processes an M3U8 playlist by converting any relative URLs to absolute,
// proxying sub-playlists (.m3u8), and proxying decryption keys.
const processM3U8 = (m3u8Data, m3u8Url, baseUrl) => {
    const lines = m3u8Data.split('\n');
    const processedLines = lines.map(line => {
        let processed = line.trim();
        if (!processed) return processed;

        // 1. Rewrite AES Key URIs to use our proxy (making them absolute first if needed)
        if (processed.startsWith('#EXT-X-KEY:')) {
            processed = processed.replace(/URI="([^"]+)"/, (match, keyUrl) => {
                let absoluteKeyUrl = keyUrl;
                if (!keyUrl.startsWith('http')) {
                    absoluteKeyUrl = new URL(keyUrl, m3u8Url).toString();
                }
                return `URI="${baseUrl}/key?url=${encodeURIComponent(absoluteKeyUrl)}"`;
            });
            return processed;
        }

        // 2. Rewrite other tag URIs (like #EXT-X-MEDIA, #EXT-X-MAP) to be absolute
        if (processed.startsWith('#') && processed.includes('URI=')) {
            processed = processed.replace(/URI="([^"]+)"/g, (match, uri) => {
                if (uri && !uri.startsWith('http')) {
                    uri = new URL(uri, m3u8Url).toString();
                }
                if (uri.includes('.m3u8') && !uri.includes('key?url=')) {
                    uri = `${baseUrl}/m3u8?url=${encodeURIComponent(uri)}`;
                }
                return `URI="${uri}"`;
            });
            return processed;
        }

        // 3. Rewrite main segment/variant playlist URLs to be absolute (and proxy variant playlists)
        if (!processed.startsWith('#')) {
            let uri = processed;
            if (!uri.startsWith('http')) {
                uri = new URL(uri, m3u8Url).toString();
            }
            if (uri.includes('.m3u8')) {
                uri = `${baseUrl}/m3u8?url=${encodeURIComponent(uri)}`;
            }
            return uri;
        }

        return processed;
    });

    return processedLines.join('\n');
};

app.get('/stream/:channelId', async (req, res) => {
    const { channelId } = req.params;
    
    try {
        const content = await fetchLiveDetail(channelId);
        const playbackJsonString = content && (content.livePlaybackJson || content.previewPlaybackJson);

        if (!playbackJsonString) {
            return res.status(404).send('Stream not found, offline, or region blocked');
        }
        
        const livePlayback = JSON.parse(playbackJsonString);
        const media = livePlayback.media || [];
        
        // Find HLS or LLHLS stream
        const hlsMedia = media.find(m => m.mediaId === 'HLS' || m.mediaId === 'LLHLS');
        
        if (hlsMedia && hlsMedia.path) {
            // Redirect Jellyfin to our proxy endpoint to ensure ffprobe/ffmpeg detects the HLS format correctly
            const host = req.get('host');
            const protocol = req.protocol;
            res.redirect(302, `${protocol}://${host}/m3u8?url=${encodeURIComponent(hlsMedia.path)}`);
        } else {
            res.status(404).send('HLS stream not found in playback info');
        }
    } catch (error) {
        console.error(`Error fetching stream for channel ${channelId}:`, error.message);
        res.status(500).send('Error fetching stream from Chzzk API');
    }
});

app.get('/m3u8', async (req, res) => {
    const m3u8Url = req.query.url;
    if (!m3u8Url) return res.status(400).send('Missing url parameter');

    try {
        const response = await axios.get(m3u8Url);
        let m3u8Data = response.data;
        const host = req.get('host');
        const protocol = req.protocol;
        const baseUrl = `${protocol}://${host}`;

        // If it's a master playlist, dynamically check and filter out unplayable variants
        if (m3u8Data.includes('#EXT-X-STREAM-INF')) {
            m3u8Data = await filterMasterPlaylist(m3u8Data, m3u8Url);
        }

        const processedM3U8 = processM3U8(m3u8Data, m3u8Url, baseUrl);

        res.header('Content-Type', 'application/vnd.apple.mpegurl');
        res.send(processedM3U8);
    } catch (error) {
        console.error(`Error proxying m3u8: ${error.message}`);
        res.status(500).send('Error proxying m3u8');
    }
});

app.get('/key', async (req, res) => {
    const keyUrl = req.query.url;
    if (!keyUrl) return res.status(400).send('Missing url parameter');

    try {
        const response = await axios.get(keyUrl, { headers: buildHeaders(), responseType: 'arraybuffer' });
        res.header('Content-Type', 'application/octet-stream');
        res.send(response.data);
    } catch (error) {
        console.error(`Error fetching key: ${error.message}`);
        res.status(500).send('Error fetching key');
    }
});

app.listen(port, () => {
    console.log(`Chzzk IPTV Proxy running on port ${port}`);
    console.log(`Playlist URL:      http://localhost:${port}/playlist.m3u`);
    console.log(`Live Playlist URL: http://localhost:${port}/playlist-live.m3u`);
    console.log(`Schedule URL:      http://localhost:${port}/schedule`);
    console.log(`EPG URL:           http://localhost:${port}/epg.xml`);
});