"""YouTube channel scanner + transcript extraction.

Uses YouTube Data API v3 for channel video listing,
youtube-transcript-api for transcript extraction.
"""

from __future__ import annotations

import logging
import os
import re
from datetime import datetime

import httpx
from youtube_transcript_api import YouTubeTranscriptApi

from core.db import conn

logger = logging.getLogger(__name__)


def _api_key() -> str:
    return os.environ["YOUTUBE_DATA_API_KEY"]


def extract_video_id(url: str) -> str:
    match = re.search(r"(?:v=|youtu\.be/)([^&?/\s]+)", url)
    if not match:
        raise ValueError(f"Cannot extract video ID from URL: {url}")
    return match.group(1)


# -- Channel operations -------------------------------------------------------

def add_channel(channel_id: str, channel_name: str, title_filter: str | None = None) -> str:
    """Register a YouTube channel. Returns DB row id."""
    sql = """
        INSERT INTO channels (channel_id, channel_name, channel_url, title_filter)
        VALUES (:cid, :cname, :curl, :tf)
        RETURNING id INTO :out_id
    """
    with conn() as c:
        cur = c.cursor()
        import oracledb
        out_id = cur.var(oracledb.STRING)
        cur.execute(sql, {
            "cid": channel_id,
            "cname": channel_name,
            "curl": f"https://www.youtube.com/channel/{channel_id}",
            "tf": title_filter,
            "out_id": out_id,
        })
        return out_id.getvalue()[0]


def deactivate_channel(channel_id: str) -> bool:
    """Deactivate a channel by channel_id. Returns True if found."""
    sql = "UPDATE channels SET is_active = 0 WHERE channel_id = :cid AND is_active = 1"
    with conn() as c:
        cur = c.cursor()
        cur.execute(sql, {"cid": channel_id})
        return cur.rowcount > 0


def deactivate_channel_by_db_id(db_id: str) -> bool:
    """Deactivate a channel by DB id. Returns True if found."""
    sql = "UPDATE channels SET is_active = 0 WHERE id = :did AND is_active = 1"
    with conn() as c:
        cur = c.cursor()
        cur.execute(sql, {"did": db_id})
        return cur.rowcount > 0


def get_active_channels() -> list[dict]:
    sql = """
        SELECT c.id, c.channel_id, c.channel_name, c.title_filter,
               (SELECT COUNT(*) FROM videos v WHERE v.channel_id = c.id) as video_count,
               (SELECT MAX(v.created_at) FROM videos v WHERE v.channel_id = c.id) as last_scanned_at
        FROM channels c
        WHERE c.is_active = 1
    """
    with conn() as c:
        cur = c.cursor()
        cur.execute(sql)
        return [
            {
                "id": r[0], "channel_id": r[1], "channel_name": r[2], "title_filter": r[3],
                "video_count": r[4] or 0,
                "last_scanned_at": r[5].isoformat() if r[5] else None,
            }
            for r in cur.fetchall()
        ]


# -- Video listing via YouTube Data API v3 ------------------------------------

def get_latest_video_date(channel_db_id: str) -> str | None:
    """Get the latest published_at for a channel's videos in ISO 8601 format."""
    sql = """
        SELECT MAX(published_at) FROM videos
        WHERE channel_id = :ch_id AND published_at IS NOT NULL
    """
    with conn() as c:
        cur = c.cursor()
        cur.execute(sql, {"ch_id": channel_db_id})
        row = cur.fetchone()
        if row and row[0]:
            return row[0].strftime("%Y-%m-%dT%H:%M:%SZ")
    return None


def _parse_iso8601_duration(dur: str) -> int:
    """Parse ISO 8601 duration (e.g. PT1M30S, PT5M, PT1H2M) to seconds."""
    import re
    m = re.match(r"PT(?:(\d+)H)?(?:(\d+)M)?(?:(\d+)S)?", dur or "")
    if not m:
        return 0
    h, mn, s = (int(x) if x else 0 for x in m.groups())
    return h * 3600 + mn * 60 + s


def _filter_shorts(videos: list[dict]) -> list[dict]:
    """Filter out YouTube Shorts (<=60s) by checking video durations via API."""
    if not videos:
        return videos
    video_ids = [v["video_id"] for v in videos]
    r = httpx.get(
        "https://www.googleapis.com/youtube/v3/videos",
        params={
            "key": _api_key(),
            "id": ",".join(video_ids),
            "part": "contentDetails",
        },
        timeout=30,
    )
    r.raise_for_status()
    durations = {}
    for item in r.json().get("items", []):
        durations[item["id"]] = _parse_iso8601_duration(
            item.get("contentDetails", {}).get("duration", "")
        )
    return [v for v in videos if durations.get(v["video_id"], 0) > 60]


def fetch_channel_videos_iter(
    channel_id: str,
    published_after: str | None = None,
    exclude_shorts: bool = True,
):
    """Yield pages of videos from a YouTube channel via Data API v3.

    Each yield is a list of dicts for one API page (up to 50).
    If exclude_shorts is True, filters out videos <= 60 seconds.
    """
    params: dict = {
        "key": _api_key(),
        "channelId": channel_id,
        "part": "snippet",
        "order": "date",
        "maxResults": 50,
        "type": "video",
    }
    if published_after:
        params["publishedAfter"] = published_after

    next_page = None

    while True:
        if next_page:
            params["pageToken"] = next_page

        r = httpx.get(
            "https://www.googleapis.com/youtube/v3/search",
            params=params,
            timeout=30,
        )
        r.raise_for_status()
        data = r.json()

        page_videos = []
        for item in data.get("items", []):
            snippet = item["snippet"]
            vid = item["id"]["videoId"]
            page_videos.append({
                "video_id": vid,
                "title": snippet["title"],
                "published_at": snippet["publishedAt"],
                "url": f"https://www.youtube.com/watch?v={vid}",
            })

        if page_videos and exclude_shorts:
            page_videos = _filter_shorts(page_videos)

        if page_videos:
            yield page_videos

        next_page = data.get("nextPageToken")
        if not next_page:
            break


def fetch_channel_videos(
    channel_id: str,
    max_results: int = 0,
    published_after: str | None = None,
) -> list[dict]:
    """Fetch video list from a YouTube channel via Data API v3.

    Args:
        max_results: 0 means fetch all available videos.
    """
    videos: list[dict] = []
    for page in fetch_channel_videos_iter(channel_id, published_after=published_after):
        videos.extend(page)
        if max_results > 0 and len(videos) >= max_results:
            break
    return videos[:max_results] if max_results > 0 else videos


# -- Transcript extraction ----------------------------------------------------

def get_transcript(video_id: str, mode: str = "auto") -> tuple[str | None, str | None]:
    """Fetch transcript using Playwright (headless browser).

    Args:
        mode: "manual" = manual only, "generated" = auto-generated only,
              "auto" = try API first, fallback to browser transcript panel.

    Returns:
        (transcript_text, source) where source describes origin, or (None, None).
    """
    # Try youtube-transcript-api first (fast path)
    text, source = _get_transcript_api(video_id, mode)
    if text:
        return text, source

    # Fallback: Playwright browser
    logger.warning("API failed for %s, trying Playwright browser", video_id)
    print(f"[TRANSCRIPT] API failed for {video_id}, trying Playwright browser", flush=True)
    return _get_transcript_browser(video_id)


def _make_ytt() -> YouTubeTranscriptApi:
    """Create YouTubeTranscriptApi with cookies if available."""
    cookie_file = os.path.join(os.path.dirname(__file__), "..", "cookies.txt")
    if os.path.exists(cookie_file):
        import http.cookiejar
        import requests
        jar = http.cookiejar.MozillaCookieJar(cookie_file)
        jar.load(ignore_discard=True, ignore_expires=True)
        session = requests.Session()
        session.cookies = jar
        return YouTubeTranscriptApi(http_client=session)
    return YouTubeTranscriptApi()


def _get_transcript_api(video_id: str, mode: str = "auto") -> tuple[str | None, str | None]:
    """Try youtube-transcript-api (fast but may be IP-blocked)."""
    ytt = _make_ytt()
    prefer = ["ko", "en"]

    try:
        transcript_list = ytt.list(video_id)
    except Exception as e:
        logger.warning("Cannot list transcripts for %s: %s", video_id, e)
        return None, None

    all_transcripts = list(transcript_list)
    manual = [t for t in all_transcripts if not t.is_generated]
    generated = [t for t in all_transcripts if t.is_generated]

    def _pick(candidates):
        for lang in prefer:
            for t in candidates:
                if t.language_code == lang:
                    return t
        return candidates[0] if candidates else None

    def _fetch(t):
        try:
            return " ".join(seg.text for seg in t.fetch()), t.language_code
        except Exception:
            return None, None

    if mode == "manual":
        t = _pick(manual)
        if t:
            text, lang = _fetch(t)
            return (text, f"manual ({lang})") if text else (None, None)
        return None, None
    elif mode == "generated":
        t = _pick(generated)
        if t:
            text, lang = _fetch(t)
            return (text, f"generated ({lang})") if text else (None, None)
        return None, None
    else:
        t = _pick(manual)
        if t:
            text, lang = _fetch(t)
            if text:
                return text, f"manual ({lang})"
        t = _pick(generated)
        if t:
            text, lang = _fetch(t)
            if text:
                return text, f"generated ({lang})"
        return None, None


def _get_transcript_browser(video_id: str) -> tuple[str | None, str | None]:
    """Fetch transcript via Playwright browser (bypasses IP blocks)."""
    try:
        from playwright.sync_api import sync_playwright
    except ImportError:
        logger.error("playwright not installed")
        return None, None

    try:
        with sync_playwright() as p:
            browser = p.chromium.launch(
                headless=False,
                args=["--disable-blink-features=AutomationControlled"],
            )
            ctx = browser.new_context(locale="ko-KR", viewport={"width": 1280, "height": 900})

            # Load YouTube cookies if available
            cookie_file = os.path.join(os.path.dirname(__file__), "..", "cookies.txt")
            if os.path.exists(cookie_file):
                import http.cookiejar
                jar = http.cookiejar.MozillaCookieJar(cookie_file)
                jar.load(ignore_discard=True, ignore_expires=True)
                pw_cookies = []
                for c in jar:
                    if "youtube" in c.domain or "google" in c.domain:
                        pw_cookies.append({
                            "name": c.name, "value": c.value,
                            "domain": c.domain, "path": c.path,
                            "secure": c.secure, "httpOnly": False,
                        })
                if pw_cookies:
                    ctx.add_cookies(pw_cookies)
                    print(f"[TRANSCRIPT] Loaded {len(pw_cookies)} cookies", flush=True)

            page = ctx.new_page()
            page.add_init_script("Object.defineProperty(navigator, 'webdriver', {get: () => false})")

            print(f"[TRANSCRIPT] Opening YouTube page for {video_id}", flush=True)
            page.goto(
                f"https://www.youtube.com/watch?v={video_id}",
                wait_until="domcontentloaded",
                timeout=30000,
            )
            page.wait_for_timeout(5000)

            # Skip ads if present
            for ad_wait in range(12):  # up to ~60s for ads
                ad_status = page.evaluate("""() => {
                    const skipBtn = document.querySelector('.ytp-skip-ad-button, .ytp-ad-skip-button, .ytp-ad-skip-button-modern, button.ytp-ad-skip-button-modern');
                    if (skipBtn) { skipBtn.click(); return 'skipped'; }
                    const adOverlay = document.querySelector('.ytp-ad-player-overlay, .ad-showing');
                    if (adOverlay) return 'playing';
                    const adBadge = document.querySelector('.ytp-ad-text');
                    if (adBadge && adBadge.textContent) return 'badge';
                    return 'none';
                }""")
                if ad_status == "none":
                    break
                print(f"[TRANSCRIPT] Ad detected: {ad_status}, waiting...", flush=True)
                if ad_status == "skipped":
                    page.wait_for_timeout(2000)
                    break
                page.wait_for_timeout(5000)

            page.wait_for_timeout(2000)
            print(f"[TRANSCRIPT] Page loaded, looking for transcript button", flush=True)

            # Click "더보기" (more actions) button first to reveal transcript option
            page.evaluate("""
                () => {
                    // Try clicking the "...더보기" button in description area
                    const moreBtn = document.querySelector('tp-yt-paper-button#expand');
                    if (moreBtn) moreBtn.click();
                }
            """)
            page.wait_for_timeout(2000)

            # Click "스크립트 표시" button via JS
            clicked = page.evaluate("""
                () => {
                    // Method 1: aria-label
                    for (const label of ['스크립트 표시', 'Show transcript']) {
                        const btns = document.querySelectorAll(`button[aria-label="${label}"]`);
                        for (const b of btns) { b.click(); return 'aria-label: ' + label; }
                    }
                    // Method 2: search all buttons by text content
                    const allBtns = document.querySelectorAll('button');
                    for (const b of allBtns) {
                        const text = b.textContent.trim();
                        if (text === '스크립트 표시' || text === 'Show transcript') {
                            b.click();
                            return 'text: ' + text;
                        }
                    }
                    // Method 3: look for transcript button in engagement panel
                    const engBtns = document.querySelectorAll('ytd-button-renderer button, ytd-button-renderer a');
                    for (const b of engBtns) {
                        const text = b.textContent.trim().toLowerCase();
                        if (text.includes('transcript') || text.includes('스크립트')) {
                            b.click();
                            return 'engagement: ' + text;
                        }
                    }
                    return false;
                }
            """)
            print(f"[TRANSCRIPT] Clicked transcript button: {clicked}", flush=True)
            if not clicked:
                # Dump available buttons for debugging
                btn_labels = page.evaluate("""
                    () => {
                        const btns = document.querySelectorAll('button[aria-label]');
                        return Array.from(btns).map(b => b.getAttribute('aria-label')).slice(0, 30);
                    }
                """)
                print(f"[TRANSCRIPT] Available buttons: {btn_labels}", flush=True)
                browser.close()
                return None, None

            # Wait for transcript panel segments to appear (max ~40s)
            page.wait_for_timeout(3000)  # initial wait for panel to render
            for attempt in range(12):
                page.wait_for_timeout(3000)
                count = page.evaluate(
                    "() => document.querySelectorAll('ytd-transcript-segment-renderer').length"
                )
                print(f"[TRANSCRIPT] Wait {(attempt+1)*3+3}s: {count} segments", flush=True)
                if count > 0:
                    break

            # Select Korean if available (language selector in transcript panel)
            page.evaluate("""
                () => {
                    // Open language dropdown and pick Korean if available
                    const menu = document.querySelector('ytd-transcript-renderer ytd-menu-renderer yt-dropdown-menu');
                    if (!menu) return;
                    const trigger = menu.querySelector('button, tp-yt-paper-button');
                    if (trigger) trigger.click();
                }
            """)
            page.wait_for_timeout(1000)
            page.evaluate("""
                () => {
                    const items = document.querySelectorAll('tp-yt-paper-listbox a, tp-yt-paper-listbox tp-yt-paper-item');
                    for (const item of items) {
                        const text = item.textContent.trim();
                        if (text.includes('한국어') || text.includes('Korean')) {
                            item.click();
                            return;
                        }
                    }
                }
            """)
            page.wait_for_timeout(2000)

            # Scroll transcript panel to load all segments
            segments = page.evaluate("""
                async () => {
                    const container = document.querySelector(
                        'ytd-transcript-segment-list-renderer #segments-container, ' +
                        'ytd-transcript-renderer #body'
                    );
                    if (!container) {
                        // Fallback: just grab what's there
                        const segs = document.querySelectorAll('ytd-transcript-segment-renderer');
                        return Array.from(segs).map(s => {
                            const txt = s.querySelector('.segment-text, yt-formatted-string.segment-text');
                            return txt ? txt.textContent.trim() : '';
                        }).filter(t => t);
                    }

                    // Scroll to bottom repeatedly to load all virtual segments
                    let prevCount = 0;
                    for (let i = 0; i < 50; i++) {
                        container.scrollTop = container.scrollHeight;
                        await new Promise(r => setTimeout(r, 300));
                        const segs = document.querySelectorAll('ytd-transcript-segment-renderer');
                        if (segs.length === prevCount && i > 3) break;
                        prevCount = segs.length;
                    }

                    const segs = document.querySelectorAll('ytd-transcript-segment-renderer');
                    return Array.from(segs).map(s => {
                        const txt = s.querySelector('.segment-text, yt-formatted-string.segment-text');
                        return txt ? txt.textContent.trim() : '';
                    }).filter(t => t);
                }
            """)

            browser.close()

            print(f"[TRANSCRIPT] Got {len(segments) if segments else 0} segments for {video_id}", flush=True)
            if segments:
                text = " ".join(segments)
                print(f"[TRANSCRIPT] Success: {len(text)} chars from {len(segments)} segments", flush=True)
                return text, "browser"
            return None, None
    except Exception as e:
        logger.error("Playwright transcript failed for %s: %s", video_id, e)
        print(f"[TRANSCRIPT] Playwright FAILED for {video_id}: {e}", flush=True)
        import traceback
        traceback.print_exc()
        return None, None


# -- DB operations for videos -------------------------------------------------

def save_video(channel_db_id: str, video: dict) -> str | None:
    """Insert a video row if not exists. Returns row id or None if duplicate."""
    sql = """
        INSERT INTO videos (channel_id, video_id, title, url, published_at, status)
        VALUES (:ch_id, :vid, :title, :url, :pub_at, 'pending')
        RETURNING id INTO :out_id
    """
    with conn() as c:
        cur = c.cursor()
        import oracledb
        out_id = cur.var(oracledb.STRING)
        try:
            pub_at = None
            if video.get("published_at"):
                pub_at = datetime.fromisoformat(
                    video["published_at"].replace("Z", "+00:00")
                )
            cur.execute(sql, {
                "ch_id": channel_db_id,
                "vid": video["video_id"],
                "title": video["title"],
                "url": video["url"],
                "pub_at": pub_at,
                "out_id": out_id,
            })
            return out_id.getvalue()[0]
        except Exception as e:
            if "UQ_VIDEOS_VID" in str(e).upper():
                return None  # duplicate
            raise


def get_existing_video_ids(channel_db_id: str) -> set[str]:
    """Get all video_ids already in DB for a channel."""
    with conn() as c:
        cur = c.cursor()
        cur.execute("SELECT video_id FROM videos WHERE channel_id = :cid", {"cid": channel_db_id})
        return {r[0] for r in cur.fetchall()}


def save_videos_batch(channel_db_id: str, videos: list[dict]) -> int:
    """Insert multiple videos in a single DB connection. Returns count of new videos."""
    if not videos:
        return 0
    import oracledb
    sql = """
        INSERT INTO videos (channel_id, video_id, title, url, published_at, status)
        VALUES (:ch_id, :vid, :title, :url, :pub_at, 'pending')
    """
    new_count = 0
    with conn() as c:
        cur = c.cursor()
        for video in videos:
            try:
                pub_at = None
                if video.get("published_at"):
                    pub_at = datetime.fromisoformat(
                        video["published_at"].replace("Z", "+00:00")
                    )
                cur.execute(sql, {
                    "ch_id": channel_db_id,
                    "vid": video["video_id"],
                    "title": video["title"],
                    "url": video["url"],
                    "pub_at": pub_at,
                })
                new_count += 1
            except Exception as e:
                if "UQ_VIDEOS_VID" in str(e).upper():
                    continue
                raise
    return new_count


def get_pending_videos(limit: int = 10) -> list[dict]:
    sql = """
        SELECT id, video_id, title, url
        FROM videos
        WHERE status = 'pending'
        ORDER BY created_at
        FETCH FIRST :n ROWS ONLY
    """
    with conn() as c:
        cur = c.cursor()
        cur.execute(sql, {"n": limit})
        return [
            {"id": r[0], "video_id": r[1], "title": r[2], "url": r[3]}
            for r in cur.fetchall()
        ]


def update_video_status(
    video_db_id: str,
    status: str,
    transcript: str | None = None,
    llm_raw: str | None = None,
) -> None:
    sets = ["status = :st", "processed_at = SYSTIMESTAMP"]
    params: dict = {"st": status, "vid": video_db_id}
    if transcript:
        sets.append("transcript_text = :txt")
        params["txt"] = transcript
    if llm_raw:
        sets.append("llm_raw_response = :llm_resp")
        params["llm_resp"] = llm_raw
    sql = f"UPDATE videos SET {', '.join(sets)} WHERE id = :vid"
    with conn() as c:
        c.cursor().execute(sql, params)


# -- Scan: fetch new videos for all active channels ---------------------------

def scan_all_channels() -> int:
    """Scan all active channels for new videos. Returns count of new videos."""
    channels = get_active_channels()
    total_new = 0
    for ch in channels:
        try:
            after = get_latest_video_date(ch["id"])
            title_filter = ch.get("title_filter")
            new_count = 0
            fetched = 0
            for page in fetch_channel_videos_iter(ch["channel_id"], published_after=after):
                fetched += len(page)
                for v in page:
                    if title_filter and title_filter not in v["title"]:
                        continue
                    row_id = save_video(ch["id"], v)
                    if row_id:
                        new_count += 1
            total_new += new_count
            logger.info(
                "Channel %s: fetched %d videos (after=%s), %d new (filter=%s)",
                ch["channel_name"], fetched, after or "all", new_count, title_filter or "none",
            )
        except Exception as e:
            logger.error("Failed to scan channel %s: %s", ch["channel_name"], e)
    return total_new