#!/usr/bin/env python3
"""检查 Markdown 中引用的本地图片是否真实存在。"""

from __future__ import annotations

import argparse
import json
from pathlib import Path
import re
import sys
from typing import Iterable, List, Optional
from urllib.parse import urlparse


IMAGE_RE = re.compile(r"!\[[^\]]*\]\(([^)]+)\)")


def die(message: str, code: int = 1) -> None:
    print(f"错误：{message}", file=sys.stderr)
    raise SystemExit(code)


def normalize_target(raw: str) -> str:
    value = raw.strip()
    if value.startswith("<") and value.endswith(">"):
        return value[1:-1].strip()
    if " " in value:
        value = value.split()[0]
    return value.strip("'\"")


def is_remote_or_anchor(target: str) -> bool:
    parsed = urlparse(target)
    return bool(parsed.scheme in {"http", "https", "data", "mailto"} or target.startswith("#"))


def find_missing(markdown_path: Path) -> List[str]:
    text = markdown_path.read_text(encoding="utf-8")
    base_dir = markdown_path.parent
    missing: List[str] = []
    for match in IMAGE_RE.finditer(text):
        target = normalize_target(match.group(1))
        if not target or is_remote_or_anchor(target):
            continue
        image_path = Path(target)
        if not image_path.is_absolute():
            image_path = base_dir / image_path
        if not image_path.exists():
            missing.append(target)
    return missing


def build_parser() -> argparse.ArgumentParser:
    parser = argparse.ArgumentParser(description="检查 Markdown 本地图片路径是否存在。")
    parser.add_argument("markdown", help="要检查的 article.md 或其他 Markdown 文件。")
    return parser


def main(argv: Optional[Iterable[str]] = None) -> int:
    parser = build_parser()
    args = parser.parse_args(list(argv) if argv is not None else None)
    markdown_path = Path(args.markdown).expanduser().resolve()
    if not markdown_path.exists():
        die(f"Markdown 文件不存在：{markdown_path}")
    missing = find_missing(markdown_path)
    result = {
        "markdown": str(markdown_path),
        "missing_count": len(missing),
        "missing": missing,
    }
    print(json.dumps(result, ensure_ascii=False, indent=2))
    return 1 if missing else 0


if __name__ == "__main__":
    raise SystemExit(main())