#!/usr/bin/env python3
"""epub-text — Extract clean reading-order text from EPUB chapters.

Usage:
  epub-text <file.epub> [--json] [--chapters] [--output PATH] [--format FORMAT]

Examples:
  epub-text book.epub                          # plain text to stdout
  epub-text book.epub --json                   # JSON with per-chapter array
  epub-text book.epub --chapters               # one file per chapter
  epub-text book.epub --output book.txt        # single output file
  epub-text book.epub --format markdown        # markdown output

Dependencies: EbookLib (pip install EbookLib), beautifulsoup4 (pip install beautifulsoup4)
"""

import argparse
import json
import os
import re
import sys
import warnings

warnings.filterwarnings("ignore")

DRY_RUN = False
JSON_OUTPUT = False
QUIET = False


def die(msg):
    print(f"Error: {msg}", file=sys.stderr)
    sys.exit(1)


def warn(msg):
    print(f"Warning: {msg}", file=sys.stderr)


def emit(json_data, text=""):
    if JSON_OUTPUT:
        print(json.dumps(json_data, indent=2, default=str))
    else:
        print(text)


def html_to_text(html_content, fmt='text'):
    """Extract plain text from HTML/XHTML content."""
    try:
        from bs4 import BeautifulSoup
    except ImportError:
        die("BeautifulSoup4 is required. Install with: pip install beautifulsoup4")

    soup = BeautifulSoup(html_content, 'html.parser')

    # Remove script and style elements
    for element in soup(['script', 'style', 'nav']):
        element.decompose()

    if fmt == 'markdown':
        # Basic markdown conversion
        text = soup.get_text('\n\n', strip=True)
        return text
    else:
        # Plain text with paragraph breaks
        paragraphs = []
        for p in soup.find_all(['p', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'li']):
            tag = p.name
            content = p.get_text(strip=True)
            if tag.startswith('h'):
                paragraphs.append(f"\n{'#' * int(tag[1])} {content}\n")
            else:
                paragraphs.append(content)
        return '\n\n'.join(paragraphs)


def check_epub(path):
    if DRY_RUN:
        return True
    if not os.path.exists(path):
        die(f"File not found: {path}")
    if not path.lower().endswith('.epub'):
        die(f"File does not appear to be an EPUB: {path}")
    return True


def main():
    global DRY_RUN, JSON_OUTPUT

    parser = argparse.ArgumentParser(
        description='Extract clean reading-order text from EPUB chapters.',
        epilog='Examples:\n  epub-text book.epub\n  epub-text book.epub --json\n  epub-text book.epub --chapters')
    parser.add_argument('epub', nargs='?', help='Path to EPUB file')
    parser.add_argument('--json', action='store_true', help='Output as JSON')
    parser.add_argument('--chapters', action='store_true', help='Output one file per chapter')
    parser.add_argument('--output', '-o', help='Output file path (single file)')
    parser.add_argument('--format', choices=['text', 'markdown'], default='text',
                        help='Output format (default: text)')
    parser.add_argument('--dry-run', '-n', action='store_true', help='Preview without reading file')
    args = parser.parse_args()

    JSON_OUTPUT = args.json
    DRY_RUN = args.dry_run

    if not args.epub:
        parser.print_help()
        sys.exit(1)

    check_epub(args.epub)

    if DRY_RUN:
        emit({'status': 'dry_run', 'file': args.epub},
             f'[dry-run] Would extract text from: {args.epub}')
        return

    try:
        from ebooklib import epub
        import ebooklib
    except ImportError:
        die("EbookLib is required. Install with: pip install EbookLib")

    book = epub.read_epub(args.epub)

    # Get spine order
    spine_ids = []
    try:
        spine_ids = [item_id for item_id, _ in book.spine]
    except Exception:
        pass

    # Map of items by id
    item_map = {}
    for item in book.get_items():
        iid = getattr(item, 'id', None)
        if iid:
            item_map[iid] = item

    # Extract text from spine-ordered documents
    chapters = []
    all_text = []

    for idx, item_id in enumerate(spine_ids):
        item = item_map.get(item_id)
        if not item:
            continue
        if not hasattr(item, 'get_type') or item.get_type() != ebooklib.ITEM_DOCUMENT:
            continue

        try:
            content = item.get_content().decode('utf-8', errors='replace')
        except Exception:
            warn(f"Could not decode content for {item_id}")
            continue

        text = html_to_text(content, args.format)
        title = getattr(item, 'title', f'Chapter {idx + 1}') or f'Chapter {idx + 1}'

        chapters.append({
            'index': idx,
            'id': item_id,
            'title': title,
            'file_name': item.get_name(),
            'text': text,
            'char_count': len(text),
        })
        all_text.append(f"# {title}\n\n{text}")

    if args.output:
        with open(args.output, 'w', encoding='utf-8') as f:
            f.write('\n\n'.join(all_text))
        emit({'status': 'written', 'output': args.output, 'chapters': len(chapters)},
             f"Written {len(chapters)} chapters to {args.output}")
    elif args.chapters:
        base = os.path.splitext(os.path.basename(args.epub))[0]
        created = []
        for ch in chapters:
            fname = f"{base}__{ch['index']:02d}__{ch['file_name'].rsplit('/', 1)[-1].replace('.xhtml', '.txt')}"
            with open(fname, 'w', encoding='utf-8') as f:
                f.write(f"# {ch['title']}\n\n{ch['text']}")
            created.append(fname)
        emit({'status': 'written', 'files': created},
             f"Written {len(created)} chapter files: {', '.join(created)}")
    elif JSON_OUTPUT:
        emit({'file': args.epub, 'chapters': chapters, 'total_chars': sum(c['char_count'] for c in chapters)})
    else:
        for ch in chapters:
            print(f"# {ch['title']}")
            print(ch['text'])
            print()


if __name__ == '__main__':
    main()