#!/usr/bin/env python3
"""Songs pipeline renderer — converts source .md files to MediaWiki pages."""

import argparse
import os
import subprocess
import sys
from datetime import datetime, timezone
from pathlib import Path

import frontmatter
import mwclient


def validate(fm: dict, path: Path) -> None:
    errors = []

    for field in ("title", "album"):
        val = fm.get(field)
        if not val or not str(val).strip():
            errors.append(f"missing or empty '{field}'")

    wiki = fm.get("wiki")
    if not isinstance(wiki, dict) or "publish" not in wiki:
        errors.append("missing 'wiki.publish'")
    elif not isinstance(wiki["publish"], bool):
        errors.append("'wiki.publish' must be a boolean (true/false), not a string")

    if "release_date" in fm and fm["release_date"]:
        try:
            datetime.strptime(str(fm["release_date"]), "%Y-%m-%d")
        except ValueError:
            errors.append("'release_date' must be YYYY-MM-DD")

    if errors:
        raise ValueError(f"{path}: " + "; ".join(errors))


def strip_first_h1(text: str) -> str:
    """Remove the first '# Heading' line and any immediately following blank line."""
    lines = text.split("\n")
    for i, line in enumerate(lines):
        if line.strip().startswith("# "):
            del lines[i]
            if i < len(lines) and lines[i].strip() == "":
                del lines[i]
            break
    return "\n".join(lines)


def markdown_to_wikitext(body: str) -> str:
    result = subprocess.run(
        ["pandoc", "-f", "markdown", "-t", "mediawiki"],
        input=body,
        capture_output=True,
        text=True,
    )
    if result.returncode != 0:
        raise RuntimeError(f"pandoc failed: {result.stderr.strip()}")
    return result.stdout


def build_wikitext(fm: dict, body_wikitext: str, source_url: str) -> str:
    now = datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ")
    banner = f"{{{{Auto-generated|source={source_url}|generated_at={now}}}}}"
    category = f"[[Category:{fm['album']}]]"
    return f"{banner}\n\n{body_wikitext}\n{category}\n"


def connect_wiki() -> mwclient.Site:
    from urllib.parse import urlparse

    api_url = os.environ["WIKI_API_URL"]
    parsed = urlparse(api_url)
    host = parsed.netloc
    # Strip api.php to get the wiki root path (e.g. "/" or "/w/")
    path = parsed.path[: parsed.path.rfind("/") + 1] or "/"
    site = mwclient.Site(host, path=path, scheme=parsed.scheme)
    site.login(os.environ["WIKI_BOT_USER"], os.environ["WIKI_BOT_PASSWORD"])
    return site


def publish_one(rel: Path, post, site: mwclient.Site, source_ref: str, gitea_repo_url: str) -> str:
    """Returns 'published', 'noop', or 'skipped'."""
    fm = post.metadata

    if not fm["wiki"]["publish"]:
        return "skipped"

    body_wikitext = markdown_to_wikitext(strip_first_h1(post.content))
    source_url = f"{gitea_repo_url}/src/commit/{source_ref}/{rel}"
    page_content = build_wikitext(fm, body_wikitext, source_url)

    page = site.pages[fm["title"]]
    if page.text() == page_content:
        return "noop"

    ref_short = source_ref[:8] if source_ref else "unknown"
    page.save(page_content, summary=f"Auto-published from {ref_short} (songs pipeline)")
    return "published"


def load_and_validate(files: list[Path], source_dir: Path) -> dict[Path, object]:
    posts = {}
    titles: dict[str, Path] = {}

    for path in files:
        if not path.exists():
            print(f"  warn: {path} not found, skipping", file=sys.stderr)
            continue

        post = frontmatter.load(str(path))
        validate(post.metadata, path)

        if post.metadata["wiki"]["publish"]:
            title = str(post.metadata["title"])
            if title in titles:
                raise ValueError(
                    f"Duplicate wiki title '{title}': {path} and {titles[title]}"
                )
            titles[title] = path

        posts[path] = post

    return posts


def main() -> None:
    parser = argparse.ArgumentParser(description="Publish song .md files to MediaWiki.")
    parser.add_argument("--source-dir", required=True, type=Path)
    parser.add_argument("--files", nargs="*", default=[], help="Relative paths within source-dir")
    parser.add_argument("--all", action="store_true", help="Publish all publishable files")
    args = parser.parse_args()

    source_dir = args.source_dir.resolve()
    source_ref = os.environ.get("SOURCE_REF", "")
    gitea_repo_url = os.environ.get("GITEA_REPO_URL", "").rstrip("/")

    if args.all:
        candidates = list(source_dir.rglob("*.md"))
    elif args.files:
        candidates = [source_dir / f for f in args.files]
    else:
        print("Nothing to do: pass --files or --all.")
        return

    files = [
        p for p in candidates
        if p.exists()
        and p.suffix == ".md"
        and "wip" not in p.relative_to(source_dir).parts
        and p.name != "README.md"
    ]

    if not files:
        print("No publishable candidates after filtering.")
        return

    print(f"Validating {len(files)} file(s)...")
    posts = load_and_validate(files, source_dir)
    print("Validation passed.")

    site = connect_wiki()

    counts = {"published": 0, "noop": 0, "skipped": 0}
    for abs_path, post in posts.items():
        rel = abs_path.relative_to(source_dir)
        outcome = publish_one(rel, post, site, source_ref, gitea_repo_url)
        counts[outcome] += 1
        print(f"  [{outcome}] {rel}")

    print(
        f"\nDone: {counts['published']} published, "
        f"{counts['noop']} unchanged, "
        f"{counts['skipped']} skipped (wiki.publish=false)."
    )


if __name__ == "__main__":
    try:
        main()
    except Exception as e:
        print(f"ERROR: {e}", file=sys.stderr)
        sys.exit(1)