#!/usr/bin/env python3
"""
Resolve a Calibre book ID to its filesystem path.

Calibre stores books at: {library_root}/{books.path}/{data.name}.{format}
"""
import argparse
import json
import os
import sqlite3
import sys

from calibre_utils import choose_preferred_format, normalize_format


def emit_error(message, code, return_code=2):
    print(json.dumps({"error": message, "error_code": code}))
    return return_code


def resolve(metadata_db, library_root, book_id, format_pref="EPUB"):
    if not os.path.exists(metadata_db):
        return emit_error(f"Metadata DB not found: {metadata_db}", "DB_NOT_FOUND", 2)

    conn = sqlite3.connect(metadata_db)
    cur = conn.cursor()

    try:
        cur.execute("SELECT title, path FROM books WHERE id = ?", (book_id,))
        row = cur.fetchone()
        if not row:
            return emit_error(f"Book {book_id} not found", "BOOK_NOT_FOUND", 1)

        title, book_path = row

        cur.execute("SELECT format, name FROM data WHERE book = ?", (book_id,))
        formats = {r[0]: r[1] for r in cur.fetchall()}

        if not formats:
            return emit_error(f"No formats found for book {book_id}", "FORMATS_MISSING", 1)

        fmt = choose_preferred_format(formats.keys(), normalize_format(format_pref))

        filename = f"{formats[fmt]}.{fmt.lower()}"
        full_path = os.path.join(library_root, book_path, filename)

        result = {
            "book_id": book_id,
            "title": title,
            "format": fmt,
            "path": full_path,
            "exists": os.path.exists(full_path),
            "available_formats": sorted(formats.keys()),
        }
        print(json.dumps(result, indent=2))
        return 0

    except Exception as e:
        return emit_error(str(e), "RESOLVE_ERROR", 3)


if __name__ == '__main__':
    p = argparse.ArgumentParser(description='Resolve book ID to file path')
    p.add_argument('--metadata-db', required=True, help='Path to metadata.db')
    p.add_argument('--library-root', required=True, help='Calibre library root')
    p.add_argument('--book-id', required=True, type=int, help='Book ID')
    p.add_argument('--format', default='EPUB', help='Preferred format (default: EPUB)')
    args = p.parse_args()
    sys.exit(resolve(args.metadata_db, args.library_root, args.book_id, args.format))