app.py

"""
Novel Scraper — Gradio UI
Universal adaptive web novel downloader.
"""
from __future__ import annotations

import asyncio
import io
import json
import os
import shutil
import threading
import time
import zipfile
from pathlib import Path
from typing import Optional

import gradio as gr

from scraper.engine import ChapterStatus, FetchMode, NovelJob
from scraper.manager import DownloadConfig, DownloadManager, load_state
from utils.logging_setup import AppLogger
from utils.range_parser import parse_chapter_range, format_range_hint

# ---------------------------------------------------------------------------
# Global state
# ---------------------------------------------------------------------------

OUTPUT_DIR = Path("output")
OUTPUT_DIR.mkdir(parents=True, exist_ok=True)

app_logger = AppLogger.get(OUTPUT_DIR)

# Active download managers keyed by job URL
_managers: dict[str, DownloadManager] = {}
_jobs: dict[str, NovelJob] = {}
_threads: dict[str, threading.Thread] = {}
_results: dict[str, Optional[Path]] = {}
_loop: Optional[asyncio.AbstractEventLoop] = None


def _get_loop() -> asyncio.AbstractEventLoop:
    global _loop
    if _loop is None or _loop.is_closed():
        _loop = asyncio.new_event_loop()
        threading.Thread(target=_loop.run_forever, daemon=True).start()
    return _loop


def _run_async(coro):
    loop = _get_loop()
    future = asyncio.run_coroutine_threadsafe(coro, loop)
    return future


# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------

def _parse_cookies(cookie_str: str) -> dict:
    """Parse 'key=value; key2=value2' or JSON cookie string."""
    cookie_str = cookie_str.strip()
    if not cookie_str:
        return {}
    if cookie_str.startswith("{") or cookie_str.startswith("["):
        try:
            data = json.loads(cookie_str)
            if isinstance(data, list):
                return {item["name"]: item["value"] for item in data if "name" in item}
            return data
        except Exception:
            return {}
    cookies = {}
    for part in cookie_str.split(";"):
        kv = part.strip().split("=", 1)
        if len(kv) == 2:
            cookies[kv[0].strip()] = kv[1].strip()
    return cookies


def _build_progress_table(job: NovelJob) -> str:
    if not job.chapters:
        return "No chapters discovered yet."
    done = job.done_count
    failed = job.failed_count
    locked = sum(1 for c in job.chapters if c.status == ChapterStatus.LOCKED)
    skipped = sum(1 for c in job.chapters if c.status == ChapterStatus.SKIPPED)
    pct = f"{job.progress*100:.1f}"
    elapsed = ""
    if job.started_at:
        e = time.time() - job.started_at
        elapsed = f"{int(e//60)}m {int(e%60)}s"
    eta = ""
    if job.started_at and done > 0 and job.progress < 1:
        rate = done / max(time.time() - job.started_at, 1)
        remaining = job.total - done
        eta_secs = remaining / rate
        eta = f"{int(eta_secs//60)}m {int(eta_secs%60)}s"

    return (
        f"**{job.title or 'Novel'}**\n\n"
        f"| Stat | Value |\n|------|-------|\n"
        f"| Status | {job.status.upper()} |\n"
        f"| Progress | {done}/{job.total} ({pct}%) |\n"
        f"| Done | ✅ {done} |\n"
        f"| Failed | ❌ {failed} |\n"
        f"| Locked | 💰 {locked} |\n"
        f"| Skipped | ⏭️ {skipped} |\n"
        f"| Elapsed | {elapsed or '—'} |\n"
        f"| ETA | {eta or '—'} |\n"
    )


def _build_failed_list(job: NovelJob) -> str:
    failed = [c for c in job.chapters if c.status == ChapterStatus.FAILED]
    if not failed:
        return "No failed chapters."
    lines = [f"**{len(failed)} failed chapters:**\n"]
    for c in failed[:50]:
        lines.append(f"- [{c.title}]({c.url}) — {c.error}")
    if len(failed) > 50:
        lines.append(f"... and {len(failed)-50} more (see failed_chapters.txt)")
    return "\n".join(lines)


def _zip_outputs(job: NovelJob) -> Optional[str]:
    """Create a ZIP of all output files for a job."""
    safe_title = "".join(c if c.isalnum() or c in " -_" else "_" for c in (job.title or "novel"))[:60]
    zip_path = OUTPUT_DIR / f"{safe_title}_package.zip"
    with zipfile.ZipFile(zip_path, "w", zipfile.ZIP_DEFLATED) as zf:
        for f in OUTPUT_DIR.iterdir():
            if f.is_file() and not f.name.startswith("."):
                zf.write(f, f.name)
    return str(zip_path)


# ---------------------------------------------------------------------------
# Core download entrypoint (runs in background thread)
# ---------------------------------------------------------------------------

def _start_download_thread(
    url: str,
    config: DownloadConfig,
    resume: bool = False,
) -> None:
    """Launch download in background thread."""
    # Try to restore state
    job = None
    if resume:
        job = load_state(url, OUTPUT_DIR)
        if job:
            app_logger.ui_log(f"📂 Resumed from saved state: {job.title}")

    if job is None:
        job = NovelJob(url=url, output_dir=OUTPUT_DIR)

    job.start_chapter = config.__dict__.get("start_chapter", 1)
    job.end_chapter = config.__dict__.get("end_chapter", 0)
    job.specific_chapters = config.__dict__.get("specific_chapters", [])

    _jobs[url] = job

    def log_cb(msg: str) -> None:
        app_logger.ui_log(msg)

    def progress_cb(j: NovelJob) -> None:
        pass  # polling-based UI

    manager = DownloadManager(job, config, log_cb=log_cb, progress_cb=progress_cb)
    _managers[url] = manager

    async def _run():
        try:
            result = await manager.run()
            _results[url] = result
        except Exception as exc:
            app_logger.ui_log(f"❌ Download error: {exc}")
            _results[url] = None
            job.status = "failed"

    future = _run_async(_run())
    _results[url] = None


# ---------------------------------------------------------------------------
# Gradio event handlers
# ---------------------------------------------------------------------------

def add_novels(
    urls_text: str,
    mode_str: str,
    rate: float,
    concurrency: int,
    retries: int,
    timeout: int,
    cookie_str: str,
    chapter_range: str,
    resume_prev: bool,
) -> tuple[str, str, str]:
    """Parse inputs and launch downloads."""
    urls = [u.strip() for u in urls_text.strip().splitlines() if u.strip()]
    if not urls:
        return "⚠️ Please enter at least one URL.", "", ""

    mode_map = {"Fast": FetchMode.FAST, "Balanced": FetchMode.BALANCED, "Compatibility": FetchMode.COMPAT}
    mode = mode_map.get(mode_str, FetchMode.BALANCED)
    cookies = _parse_cookies(cookie_str)

    # Parse range
    specific = parse_chapter_range(chapter_range)
    start_ch = 1
    end_ch = 0
    if specific:
        start_ch = min(specific)
        end_ch = max(specific)

    config = DownloadConfig(
        mode=mode,
        max_concurrent=max(1, min(concurrency, 10)),
        rate_limit=max(0.1, 1.0 / max(rate, 0.1)),
        max_retries=max(1, retries),
        timeout=max(5, timeout),
        cookies=cookies,
        output_dir=OUTPUT_DIR,
    )
    config.__dict__["start_chapter"] = start_ch
    config.__dict__["end_chapter"] = end_ch
    config.__dict__["specific_chapters"] = specific

    messages = []
    for url in urls:
        if url in _jobs and _jobs[url].status == "running":
            messages.append(f"⚠️ Already running: {url}")
            continue
        app_logger.ui_log(f"🚀 Queuing: {url}")
        t = threading.Thread(
            target=_start_download_thread,
            args=(url, config, resume_prev),
            daemon=True,
        )
        t.start()
        _threads[url] = t
        messages.append(f"✅ Started: {url}")

    return "\n".join(messages), "", app_logger.get_ui_text()


def pause_job(url: str) -> str:
    url = url.strip()
    if url in _managers:
        _managers[url].pause()
        return f"⏸️ Paused: {url}"
    return "⚠️ No active download for that URL."


def resume_job(url: str) -> str:
    url = url.strip()
    if url in _managers:
        _managers[url].resume()
        return f"▶️ Resumed: {url}"
    return "⚠️ No active download for that URL."


def cancel_job(url: str) -> str:
    url = url.strip()
    if url in _managers:
        _managers[url].cancel()
        return f"🚫 Cancelled: {url}"
    return "⚠️ No active download for that URL."


def retry_failed(url: str) -> str:
    url = url.strip()
    if url not in _jobs:
        return "⚠️ No job found for that URL."
    job = _jobs[url]
    for c in job.chapters:
        if c.status == ChapterStatus.FAILED:
            c.status = ChapterStatus.PENDING
            c.retries = 0
            c.error = ""
    app_logger.ui_log(f"🔄 Reset failed chapters for retry: {url}")
    return f"✅ Failed chapters reset for retry."


def get_status() -> tuple[str, str, str, gr.File]:
    """Poll status — called by timer."""
    if not _jobs:
        return "No downloads started.", "", app_logger.get_ui_text(), None

    progress_parts = []
    failed_parts = []

    for url, job in _jobs.items():
        progress_parts.append(_build_progress_table(job))
        failed_parts.append(_build_failed_list(job))

    # Find completed downloads for file output
    output_file = None
    for url, result_path in _results.items():
        if result_path and Path(result_path).exists():
            output_file = str(result_path)
            break

    return (
        "\n\n---\n\n".join(progress_parts),
        "\n\n---\n\n".join(failed_parts),
        app_logger.get_ui_text(200),
        output_file,
    )


def get_download_files() -> list[str]:
    """Return list of available output files."""
    files = []
    for f in OUTPUT_DIR.iterdir():
        if f.is_file() and not f.name.startswith(".") and f.suffix in (".txt", ".zip"):
            files.append(str(f))
    return files


def create_zip() -> Optional[str]:
    if not _jobs:
        return None
    # Use the most recent job
    job = list(_jobs.values())[-1]
    return _zip_outputs(job)


def clear_logs() -> str:
    app_logger.ring.clear()
    return ""


def preview_extraction(url: str, mode_str: str, cookie_str: str) -> str:
    """Preview extracted content from a URL without saving."""
    url = url.strip()
    if not url:
        return "⚠️ Enter a URL to preview."

    mode_map = {"Fast": FetchMode.FAST, "Balanced": FetchMode.BALANCED, "Compatibility": FetchMode.COMPAT}
    mode = mode_map.get(mode_str, FetchMode.BALANCED)
    cookies = _parse_cookies(cookie_str)

    from scraper.engine import create_session, smart_fetch
    from scraper.extractor import extract_chapter

    async def _preview():
        session = await create_session(cookies)
        try:
            html, status = await smart_fetch(session, url, mode=mode, cookies=cookies)
            title, content, paras = extract_chapter(html)
            preview = f"**Title:** {title}\n\n**Preview (first 500 chars):**\n\n{content[:500]}..."
            return preview
        finally:
            await session.close()

    try:
        future = _run_async(_preview())
        result = future.result(timeout=30)
        return result
    except Exception as exc:
        return f"❌ Preview failed: {exc}"


# ---------------------------------------------------------------------------
# CSS theme — redesigned: light/dark toggle, mobile-first, clean typography
# ---------------------------------------------------------------------------


CUSTOM_CSS = """
@import url('https://fonts.googleapis.com/css2?family=Instrument+Serif:ital@0;1&family=DM+Sans:wght@300;400;500;600&family=DM+Mono:wght@400;500&display=swap');

/* ─── DESIGN TOKENS ─────────────────────────────────────────────────────── */
:root {
  /* Light theme (default) */
  --bg:          #f5f4f0;
  --bg-raised:   #ffffff;
  --bg-sunken:   #ece9e3;
  --bg-input:    #ffffff;
  --surface:     #f0ede7;
  --border:      #d8d4cc;
  --border-focus:#2a2a2a;
  --text-1:      #1a1a1a;
  --text-2:      #5a5752;
  --text-3:      #9a9590;
  --accent:      #1a1a1a;
  --accent-bg:   #1a1a1a;
  --accent-fg:   #ffffff;
  --green:       #1a7a4a;
  --green-bg:    #edf7f1;
  --red:         #c0392b;
  --red-bg:      #fdf2f1;
  --amber:       #b35c00;
  --amber-bg:    #fef8ec;
  --log-bg:      #1c1c1c;
  --log-text:    #d4f0c0;
  --shadow-sm:   0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.05);
  --shadow-md:   0 4px 12px rgba(0,0,0,.10), 0 2px 4px rgba(0,0,0,.06);
  --r:           10px;
  --r-sm:        7px;
  --r-lg:        16px;
  --transition:  all .18s cubic-bezier(.4,0,.2,1);
}

/* Dark theme */
[data-theme="dark"] {
  --bg:          #111111;
  --bg-raised:   #1a1a1a;
  --bg-sunken:   #0d0d0d;
  --bg-input:    #1e1e1e;
  --surface:     #161616;
  --border:      #2e2e2e;
  --border-focus:#ffffff;
  --text-1:      #f0f0f0;
  --text-2:      #888888;
  --text-3:      #555555;
  --accent:      #f0f0f0;
  --accent-bg:   #f0f0f0;
  --accent-fg:   #111111;
  --green:       #4ade80;
  --green-bg:    #0f2a1a;
  --red:         #f87171;
  --red-bg:      #2a0f0f;
  --amber:       #fbbf24;
  --amber-bg:    #2a1f05;
  --log-bg:      #0a0a0a;
  --log-text:    #7dde8a;
  --shadow-sm:   0 1px 3px rgba(0,0,0,.4);
  --shadow-md:   0 4px 12px rgba(0,0,0,.5);
}

/* ─── RESET & BASE ───────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; }

html { font-size: 16px; }

body, .gradio-container {
  background: var(--bg) !important;
  color: var(--text-1) !important;
  font-family: 'DM Sans', system-ui, sans-serif !important;
  transition: background .25s, color .25s !important;
  -webkit-font-smoothing: antialiased !important;
}

.gradio-container {
  max-width: 900px !important;
  margin: 0 auto !important;
  padding: 0 16px 48px !important;
}

/* ─── SCROLLBAR ─────────────────────────────────────────────────────────── */
::-webkit-scrollbar { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 99px; }

/* ─── HEADER ─────────────────────────────────────────────────────────────── */
.ns-header {
  padding: 36px 0 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 28px;
  flex-wrap: wrap;
}

.ns-brand { display: flex; flex-direction: column; gap: 4px; }

.ns-title {
  font-family: 'Instrument Serif', Georgia, serif;
  font-size: clamp(1.6rem, 5vw, 2.2rem);
  font-weight: 400;
  font-style: italic;
  color: var(--text-1);
  line-height: 1;
  letter-spacing: -0.3px;
}

.ns-sub {
  font-size: 0.78rem;
  font-weight: 400;
  color: var(--text-3);
  letter-spacing: 0.4px;
}

/* ─── THEME TOGGLE ───────────────────────────────────────────────────────── */
.theme-toggle-wrap { display: flex; align-items: center; gap: 8px; flex-shrink: 0; }

.theme-toggle {
  position: relative;
  width: 48px;
  height: 26px;
  flex-shrink: 0;
}

.theme-toggle input { opacity: 0; width: 0; height: 0; position: absolute; }

.theme-toggle-track {
  position: absolute;
  inset: 0;
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: 99px;
  cursor: pointer;
  transition: var(--transition);
}

.theme-toggle-track::after {
  content: '';
  position: absolute;
  top: 3px; left: 3px;
  width: 18px; height: 18px;
  border-radius: 50%;
  background: var(--text-2);
  transition: var(--transition);
}

.theme-toggle input:checked + .theme-toggle-track { background: var(--text-1); border-color: var(--text-1); }
.theme-toggle input:checked + .theme-toggle-track::after { transform: translateX(22px); background: var(--bg); }

.theme-label { font-size: 0.78rem; color: var(--text-3); user-select: none; min-width: 30px; }

/* ─── TABS ───────────────────────────────────────────────────────────────── */
.tabs { margin-top: 0 !important; }

.tab-nav {
  display: flex !important;
  gap: 4px !important;
  background: var(--surface) !important;
  border: 1px solid var(--border) !important;
  border-radius: var(--r) !important;
  padding: 4px !important;
  overflow-x: auto !important;
  overflow-y: hidden !important;
  scrollbar-width: none !important;
  margin-bottom: 20px !important;
  flex-wrap: nowrap !important;
}

.tab-nav::-webkit-scrollbar { display: none; }

.tab-nav button {
  background: transparent !important;
  border: none !important;
  border-radius: var(--r-sm) !important;
  color: var(--text-2) !important;
  font-family: 'DM Sans', sans-serif !important;
  font-size: 0.82rem !important;
  font-weight: 500 !important;
  padding: 7px 14px !important;
  white-space: nowrap !important;
  transition: var(--transition) !important;
  cursor: pointer !important;
  flex-shrink: 0 !important;
}

.tab-nav button:hover {
  color: var(--text-1) !important;
  background: var(--bg-raised) !important;
}

.tab-nav button.selected {
  background: var(--bg-raised) !important;
  color: var(--text-1) !important;
  font-weight: 600 !important;
  box-shadow: var(--shadow-sm) !important;
}

/* ─── BLOCKS / CARDS ─────────────────────────────────────────────────────── */
.gr-group, .gradio-group {
  background: var(--bg-raised) !important;
  border: 1px solid var(--border) !important;
  border-radius: var(--r-lg) !important;
  box-shadow: var(--shadow-sm) !important;
  padding: 20px !important;
  margin-bottom: 14px !important;
}

/* ─── LABELS ─────────────────────────────────────────────────────────────── */
label span, .label-wrap span, .gr-form label {
  font-family: 'DM Sans', sans-serif !important;
  font-size: 0.75rem !important;
  font-weight: 600 !important;
  letter-spacing: 0.5px !important;
  text-transform: uppercase !important;
  color: var(--text-2) !important;
}

/* ─── INPUTS ─────────────────────────────────────────────────────────────── */
textarea,
input[type="text"],
input[type="number"],
input[type="search"],
select,
.gr-input,
.gr-textarea {
  background: var(--bg-input) !important;
  border: 1.5px solid var(--border) !important;
  border-radius: var(--r-sm) !important;
  color: var(--text-1) !important;
  font-family: 'DM Sans', sans-serif !important;
  font-size: 0.88rem !important;
  padding: 10px 12px !important;
  transition: var(--transition) !important;
  box-shadow: none !important;
}

textarea:focus,
input[type="text"]:focus,
input[type="number"]:focus,
select:focus {
  border-color: var(--border-focus) !important;
  box-shadow: 0 0 0 3px rgba(0,0,0,0.06) !important;
  outline: none !important;
}

[data-theme="dark"] textarea:focus,
[data-theme="dark"] input:focus {
  box-shadow: 0 0 0 3px rgba(255,255,255,0.06) !important;
}

/* placeholder */
textarea::placeholder, input::placeholder { color: var(--text-3) !important; }

/* ─── SLIDERS ─────────────────────────────────────────────────────────────── */
input[type="range"] {
  accent-color: var(--text-1) !important;
  height: 4px !important;
}

/* ─── BUTTONS ─────────────────────────────────────────────────────────────── */
button, .gr-button {
  font-family: 'DM Sans', sans-serif !important;
  font-size: 0.85rem !important;
  font-weight: 600 !important;
  border-radius: var(--r-sm) !important;
  padding: 10px 18px !important;
  transition: var(--transition) !important;
  cursor: pointer !important;
  letter-spacing: 0.1px !important;
}

/* Primary */
button.gr-button-primary, .gr-button-primary {
  background: var(--accent-bg) !important;
  color: var(--accent-fg) !important;
  border: 1.5px solid var(--accent-bg) !important;
  box-shadow: var(--shadow-sm) !important;
}

button.gr-button-primary:hover {
  opacity: 0.88 !important;
  box-shadow: var(--shadow-md) !important;
  transform: translateY(-1px) !important;
}

button.gr-button-primary:active { transform: translateY(0) !important; }

/* Secondary */
button.gr-button-secondary, .gr-button-secondary {
  background: var(--bg-raised) !important;
  color: var(--text-1) !important;
  border: 1.5px solid var(--border) !important;
}

button.gr-button-secondary:hover {
  border-color: var(--text-1) !important;
  background: var(--surface) !important;
}

/* Icon-only small buttons */
.btn-icon {
  padding: 8px 12px !important;
  font-size: 0.8rem !important;
}

/* ─── CHECKBOX ───────────────────────────────────────────────────────────── */
input[type="checkbox"] { accent-color: var(--text-1) !important; }

/* ─── DROPDOWN ───────────────────────────────────────────────────────────── */
.gr-dropdown > div {
  background: var(--bg-input) !important;
  border: 1.5px solid var(--border) !important;
  border-radius: var(--r-sm) !important;
  color: var(--text-1) !important;
}

/* ─── ACCORDION ──────────────────────────────────────────────────────────── */
.gr-accordion {
  background: var(--surface) !important;
  border: 1px solid var(--border) !important;
  border-radius: var(--r) !important;
}

.gr-accordion > .label-wrap {
  padding: 12px 16px !important;
}

/* ─── MARKDOWN ───────────────────────────────────────────────────────────── */
.gr-markdown, .output-markdown, .prose {
  color: var(--text-1) !important;
  font-family: 'DM Sans', sans-serif !important;
  font-size: 0.88rem !important;
  line-height: 1.75 !important;
}

.gr-markdown h1, .gr-markdown h2, .gr-markdown h3 {
  font-family: 'Instrument Serif', serif !important;
  font-style: italic !important;
  font-weight: 400 !important;
  color: var(--text-1) !important;
  margin: 1.2em 0 0.5em !important;
}

.gr-markdown h2 { font-size: 1.25rem !important; }
.gr-markdown h3 { font-size: 1.05rem !important; }

.gr-markdown table {
  width: 100% !important;
  border-collapse: collapse !important;
  font-size: 0.83rem !important;
  border-radius: var(--r-sm) !important;
  overflow: hidden !important;
}

.gr-markdown th {
  background: var(--surface) !important;
  color: var(--text-2) !important;
  padding: 8px 12px !important;
  font-size: 0.72rem !important;
  font-weight: 600 !important;
  letter-spacing: 0.5px !important;
  text-transform: uppercase !important;
  text-align: left !important;
}

.gr-markdown td {
  padding: 8px 12px !important;
  border-bottom: 1px solid var(--border) !important;
  color: var(--text-1) !important;
  vertical-align: top !important;
}

.gr-markdown tr:last-child td { border-bottom: none !important; }

.gr-markdown code {
  background: var(--surface) !important;
  color: var(--text-1) !important;
  padding: 1px 6px !important;
  border-radius: 4px !important;
  font-family: 'DM Mono', monospace !important;
  font-size: 0.8rem !important;
  border: 1px solid var(--border) !important;
}

.gr-markdown pre {
  background: var(--bg-sunken) !important;
  border: 1px solid var(--border) !important;
  border-radius: var(--r-sm) !important;
  padding: 14px !important;
  overflow-x: auto !important;
}

.gr-markdown a { color: var(--text-1) !important; text-underline-offset: 3px !important; }

/* ─── LOGS ───────────────────────────────────────────────────────────────── */
.logs-area textarea {
  font-family: 'DM Mono', monospace !important;
  font-size: 0.77rem !important;
  line-height: 1.65 !important;
  color: var(--log-text) !important;
  background: var(--log-bg) !important;
  border: 1px solid #2a2a2a !important;
  border-radius: var(--r) !important;
  padding: 14px !important;
}

[data-theme="dark"] .logs-area textarea {
  background: #080808 !important;
}

/* ─── STATUS PILLS ───────────────────────────────────────────────────────── */
.pill {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 3px 10px;
  border-radius: 99px;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.3px;
}

.pill-green  { background: var(--green-bg);  color: var(--green);  }
.pill-red    { background: var(--red-bg);    color: var(--red);    }
.pill-amber  { background: var(--amber-bg);  color: var(--amber);  }

/* ─── FILE DOWNLOAD ──────────────────────────────────────────────────────── */
.file-zone {
  background: var(--surface) !important;
  border: 1.5px dashed var(--border) !important;
  border-radius: var(--r) !important;
}

/* ─── STATUS TEXTBOX ─────────────────────────────────────────────────────── */
.status-box textarea {
  background: var(--surface) !important;
  border: 1px solid var(--border) !important;
  font-size: 0.83rem !important;
  color: var(--text-1) !important;
}

/* ─── SECTION DIVIDERS ───────────────────────────────────────────────────── */
.section-label {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.8px;
  text-transform: uppercase;
  color: var(--text-3);
  margin: 20px 0 10px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--border);
}

/* ─── INFO TEXT ──────────────────────────────────────────────────────────── */
.gr-form .info, .description { color: var(--text-3) !important; font-size: 0.77rem !important; }

/* ─── ROW GAPS (mobile-friendly) ─────────────────────────────────────────── */
.gr-row { gap: 12px !important; }

@media (max-width: 640px) {
  .gradio-container { padding: 0 12px 40px !important; }
  .ns-header { padding: 24px 0 20px; }
  .gr-row { flex-direction: column !important; }
  .tab-nav button { padding: 7px 10px !important; font-size: 0.78rem !important; }
  button, .gr-button { padding: 10px 14px !important; font-size: 0.83rem !important; }
}

/* ─── GRADIO INTERNAL OVERRIDES ──────────────────────────────────────────── */
.block { background: transparent !important; border: none !important; box-shadow: none !important; }
.form { gap: 12px !important; }
footer { display: none !important; }
.gap { gap: 12px !important; }
"""

# ---------------------------------------------------------------------------
# Build Gradio app — redesigned layout
# ---------------------------------------------------------------------------

def build_app() -> gr.Blocks:
    with gr.Blocks(
        title="Novel Scraper",
        css=CUSTOM_CSS,
        theme=gr.themes.Base(
            font=[gr.themes.GoogleFont("DM Sans"), "ui-sans-serif"],
        ),
        analytics_enabled=False,
    ) as demo:

        # ── Header with theme toggle ─────────────────────────────────────
        gr.HTML("""
        <div class="ns-header" id="ns-header">
          <div class="ns-brand">
            <div class="ns-title">Novel Scraper</div>
            <div class="ns-sub">Universal adaptive web novel downloader</div>
          </div>
          <div class="theme-toggle-wrap">
            <span class="theme-label" id="theme-lbl">Light</span>
            <label class="theme-toggle" title="Toggle dark mode">
              <input type="checkbox" id="theme-chk" onchange="toggleTheme(this)">
              <span class="theme-toggle-track"></span>
            </label>
          </div>
        </div>

        <script>
        function toggleTheme(chk) {
          const root = document.documentElement;
          const lbl = document.getElementById('theme-lbl');
          if (chk.checked) {
            root.setAttribute('data-theme', 'dark');
            lbl.textContent = 'Dark';
            localStorage.setItem('ns-theme', 'dark');
          } else {
            root.removeAttribute('data-theme');
            lbl.textContent = 'Light';
            localStorage.setItem('ns-theme', 'light');
          }
        }
        // Restore saved preference
        (function() {
          const saved = localStorage.getItem('ns-theme');
          if (saved === 'dark') {
            document.documentElement.setAttribute('data-theme', 'dark');
            const chk = document.getElementById('theme-chk');
            const lbl = document.getElementById('theme-lbl');
            if (chk) { chk.checked = true; }
            if (lbl) { lbl.textContent = 'Dark'; }
          }
        })();
        </script>
        """)

        with gr.Tabs():

            # ── TAB 1: Download ──────────────────────────────────────────
            with gr.Tab("Download"):

                # ── URL Input ────────────────────────────────────────────
                with gr.Group():
                    urls_input = gr.Textbox(
                        label="Novel URLs",
                        placeholder="https://novelsite.com/my-novel\nhttps://anothersite.com/story\n\nOne URL per line — supports multiple novels",
                        lines=4,
                    )
                    with gr.Row():
                        chapter_range = gr.Textbox(
                            label="Chapter Range",
                            placeholder="all  /  1-100  /  1-50,70-90  /  5,10,15",
                            lines=1,
                            scale=3,
                        )
                        resume_check = gr.Checkbox(
                            label="Resume previous",
                            value=True,
                            scale=1,
                        )

                # ── Settings ─────────────────────────────────────────────
                with gr.Accordion("Settings", open=False):
                    mode_select = gr.Dropdown(
                        label="Fetch Mode",
                        choices=["Fast", "Balanced", "Compatibility"],
                        value="Balanced",
                        info="Fast = aiohttp · Balanced = + cloudscraper · Compatibility = + Playwright browser",
                    )
                    with gr.Row():
                        rate_slider = gr.Slider(
                            label="Chapters per second",
                            minimum=0.1, maximum=10.0, step=0.1, value=1.0,
                        )
                        concurrency = gr.Slider(
                            label="Concurrent workers",
                            minimum=1, maximum=10, step=1, value=3,
                        )
                    with gr.Row():
                        retries = gr.Slider(
                            label="Max retries",
                            minimum=1, maximum=30, step=1, value=10,
                        )
                        timeout = gr.Slider(
                            label="Timeout (sec)",
                            minimum=5, maximum=120, step=5, value=30,
                        )

                # ── Cookies ──────────────────────────────────────────────
                with gr.Accordion("Cookies / Authentication", open=False):
                    cookie_input = gr.Textbox(
                        label="Browser Cookies",
                        placeholder='Paste as: key=value; key2=value2\n\nOr as JSON: [{"name":"sid","value":"abc123"}]',
                        lines=3,
                        info="For age-gated or login-required sites. Export from browser DevTools → Application → Cookies.",
                    )

                # ── Actions ───────────────────────────────────────────────
                with gr.Row():
                    start_btn  = gr.Button("Start Download", variant="primary", scale=3)
                    preview_btn = gr.Button("Preview", variant="secondary", scale=1)

                status_msg = gr.Textbox(
                    label="Status",
                    lines=2,
                    interactive=False,
                    elem_classes=["status-box"],
                    show_label=True,
                )

                # ── Queue Controls ────────────────────────────────────────
                with gr.Accordion("Queue Controls (pause / cancel / retry)", open=False):
                    control_url = gr.Textbox(
                        label="Target URL",
                        placeholder="Paste the novel URL to control",
                        lines=1,
                    )
                    with gr.Row():
                        pause_btn  = gr.Button("⏸ Pause",        variant="secondary")
                        resume_btn = gr.Button("▶ Resume",        variant="secondary")
                        cancel_btn = gr.Button("✕ Cancel",        variant="secondary")
                        retry_btn  = gr.Button("↺ Retry Failed",  variant="secondary")
                    control_msg = gr.Textbox(
                        label="Output",
                        lines=1,
                        interactive=False,
                        elem_classes=["status-box"],
                    )

                # ── Preview pane ──────────────────────────────────────────
                preview_out = gr.Markdown(
                    value="",
                    label="",
                    visible=True,
                )

            # ── TAB 2: Progress ──────────────────────────────────────────
            with gr.Tab("Progress"):
                with gr.Row():
                    refresh_btn = gr.Button("↻ Refresh", variant="secondary")
                with gr.Group():
                    progress_display = gr.Markdown(
                        value="*Start a download to see progress here.*",
                    )
                with gr.Group():
                    gr.HTML('<div class="section-label">Failed Chapters</div>')
                    failed_display = gr.Markdown(value="*None*")

            # ── TAB 3: Logs ───────────────────────────────────────────────
            with gr.Tab("Logs"):
                with gr.Row():
                    refresh_logs_btn = gr.Button("↻ Refresh", variant="secondary")
                    clear_logs_btn   = gr.Button("Clear",     variant="secondary")
                logs_out = gr.Textbox(
                    label="",
                    lines=22,
                    interactive=False,
                    max_lines=22,
                    elem_classes=["logs-area"],
                    value="",
                    show_label=False,
                )

            # ── TAB 4: Files ──────────────────────────────────────────────
            with gr.Tab("Files"):
                with gr.Row():
                    list_files_btn = gr.Button("List Files",       variant="secondary")
                    zip_btn        = gr.Button("Create ZIP",        variant="secondary")
                with gr.Group():
                    files_display = gr.Markdown(value="*Click 'List Files' to see available downloads.*")
                file_download = gr.File(
                    label="Download",
                    interactive=False,
                    elem_classes=["file-zone"],
                )

            # ── TAB 5: Help ───────────────────────────────────────────────
            with gr.Tab("Help"):
                gr.Markdown("""
## Quick Start

1. Paste one or more novel URLs (one per line)
2. Optionally set a chapter range — leave blank for all
3. Click **Start Download**
4. Watch progress in the **Progress** tab
5. Grab your `.txt` from the **Files** tab

---

## Chapter Ranges

| Expression | Meaning |
|------------|---------|
| *(blank)* or `all` | Every chapter |
| `1-100` | Chapters 1 to 100 |
| `50-200` | Chapters 50 to 200 |
| `1,5,9,20` | Specific chapters |
| `1-50,70-90` | Combined ranges |

---

## Fetch Modes

| Mode | Description |
|------|-------------|
| **Fast** | aiohttp only — fastest |
| **Balanced** | + cloudscraper fallback *(recommended)* |
| **Compatibility** | + Playwright browser — handles almost any site |

---

## Cookies

For login-required or age-gated sites:
1. Log in to the site in your browser
2. Open DevTools (`F12`) → **Application** → **Cookies**
3. Copy as `key=value; key2=value2`
4. Or export as JSON from a cookie manager extension

---

## Output Format

Clean plain text — no dividers, no noise:

```
Chapter 1: The Beginning

The hero walked into the forest...

Chapter 2: The Trial

Dark clouds gathered overhead...
```

---

## Tips

- Start with **1 chapter/sec** and **3 workers** to avoid bans
- Use **Compatibility** mode for 403/503 errors
- Enable **Resume previous** to continue interrupted downloads
- Large novels (5000+ chapters): use 2–3 workers
- CAPTCHA sites: pause, solve in browser, paste fresh cookies

---

## Supported Site Structures

- Direct chapter lists on the main page
- TOC sub-pages: `/chapters`, `/toc`, `/episodes`, `/contents`
- Paginated lists: `?page=N`, `/page/N`
- JSON chapter data embedded in `<script>` tags
- Cloudflare-protected sites (Compatibility mode)
""")

        # ── Event wiring ─────────────────────────────────────────────────

        start_btn.click(
            fn=add_novels,
            inputs=[urls_input, mode_select, rate_slider, concurrency,
                    retries, timeout, cookie_input, chapter_range, resume_check],
            outputs=[status_msg, control_msg, logs_out],
        )

        preview_btn.click(
            fn=preview_extraction,
            inputs=[urls_input, mode_select, cookie_input],
            outputs=[preview_out],
        )

        pause_btn.click(fn=pause_job,    inputs=[control_url], outputs=[control_msg])
        resume_btn.click(fn=resume_job,  inputs=[control_url], outputs=[control_msg])
        cancel_btn.click(fn=cancel_job,  inputs=[control_url], outputs=[control_msg])
        retry_btn.click(fn=retry_failed, inputs=[control_url], outputs=[control_msg])

        def do_refresh():
            prog, failed, logs, _ = get_status()
            return prog, failed, logs

        refresh_btn.click(fn=do_refresh, outputs=[progress_display, failed_display, logs_out])
        refresh_logs_btn.click(fn=lambda: app_logger.get_ui_text(300), outputs=[logs_out])
        clear_logs_btn.click(fn=clear_logs, outputs=[logs_out])

        def list_files():
            files = get_download_files()
            if not files:
                return "*No output files yet — start a download first.*", None
            lines = [f"- `{Path(f).name}` — {Path(f).stat().st_size // 1024} KB" for f in files]
            return "\n".join(lines), files[0] if files else None

        list_files_btn.click(fn=list_files, outputs=[files_display, file_download])

        def make_zip():
            p = create_zip()
            if p:
                return f"ZIP created: `{Path(p).name}`", p
            return "No files to ZIP yet.", None

        zip_btn.click(fn=make_zip, outputs=[files_display, file_download])

    return demo


# ---------------------------------------------------------------------------
# Main entry point
# ---------------------------------------------------------------------------

if __name__ == "__main__":
    app = build_app()
    app.launch(
        server_name="0.0.0.0",
        server_port=int(os.environ.get("PORT", 7860)),
        share=False,
        show_error=True,
    )