#!/usr/bin/env -S uv run --script
# /// script
# dependencies = ["pyyaml"]
# ///

"""
project.py — backend for /project skill.
Deterministic CRUD for project markdown files with YAML frontmatter.
"""

from __future__ import annotations

import argparse
import json
import re
import sys
from datetime import date
from pathlib import Path

import yaml

WORKSPACE = Path(__file__).resolve().parent.parent.parent.parent
PROJECTS_DIR = WORKSPACE / "projects"

# Valid statuses and priorities
STATUSES = {"active", "paused", "done"}
PRIORITIES = {"high", "medium", "low"}


def _slugify(name: str) -> str:
    """Kebab-case slug from first few words of name. Max 4 words."""
    words = re.sub(r"[^a-zA-Z0-9\s]", "", name).lower().split()
    words = words[:4]
    return "-".join(words) if words else "project"


def _list_projects() -> list[dict]:
    """Parse frontmatter from all .md files in projects/."""
    if not PROJECTS_DIR.exists():
        return []
    projects = []
    for path in sorted(PROJECTS_DIR.glob("*.md")):
        text = path.read_text(encoding="utf-8")
        frontmatter, _ = _split_frontmatter(text)
        if frontmatter:
            meta = yaml.safe_load(frontmatter) or {}
            meta["_file"] = path.name
            projects.append(meta)
    return projects


def _split_frontmatter(text: str) -> tuple[str | None, str]:
    """Split YAML frontmatter from body. Returns (frontmatter_yaml, body)."""
    if not text.startswith("---\n"):
        return None, text
    end = text.find("\n---\n", 4)
    if end == -1:
        return None, text
    return text[4:end], text[end + 5 :]


def _load_file(slug: str) -> tuple[Path, str, str | None, str]:
    """Load project file. Returns (path, full_text, frontmatter_yaml, body)."""
    path = PROJECTS_DIR / f"{slug}.md"
    if not path.exists():
        raise FileNotFoundError(f"Project '{slug}' not found ({path.name})")
    text = path.read_text(encoding="utf-8")
    fm, body = _split_frontmatter(text)
    return path, text, fm, body


def _write_file(path: Path, frontmatter: dict, body: str) -> None:
    """Write project file with YAML frontmatter."""
    fm_yaml = yaml.safe_dump(frontmatter, allow_unicode=True, sort_keys=False, default_flow_style=False)
    path.write_text(f"---\n{fm_yaml}---\n{body}", encoding="utf-8")


# ---------------------------------------------------------------------------
# Commands
# ---------------------------------------------------------------------------

def cmd_add(args: argparse.Namespace) -> int:
    name = (args.name or "").strip()
    if not name:
        print(json.dumps({"error": "name must not be empty"}), file=sys.stderr)
        return 1

    slug = _slugify(name)
    PROJECTS_DIR.mkdir(parents=True, exist_ok=True)
    path = PROJECTS_DIR / f"{slug}.md"
    if path.exists():
        print(json.dumps({"error": f"project '{slug}' already exists"}), file=sys.stderr)
        return 1

    priority = (args.priority or "medium").lower()
    if priority not in PRIORITIES:
        print(json.dumps({"error": f"invalid priority '{priority}' — use high/medium/low"}), file=sys.stderr)
        return 1

    frontmatter = {
        "status": "active",
        "priority": priority,
        "created": date.today().isoformat(),
        "slug": slug,
    }
    body = f"# {name}\n\n## Poznámky\n\n## Další krok\n\n"
    _write_file(path, frontmatter, body)
    print(json.dumps({"added": {"slug": slug, "name": name, "path": str(path.relative_to(WORKSPACE))}}, ensure_ascii=False))
    return 0


def cmd_list(_args: argparse.Namespace) -> int:
    projects = _list_projects()
    active = [p for p in projects if p.get("status") == "active"]
    # Sort by priority: high > medium > low
    priority_order = {"high": 0, "medium": 1, "low": 2}
    active.sort(key=lambda p: priority_order.get(p.get("priority", "medium"), 1))
    print(json.dumps({"projects": active}, ensure_ascii=False))
    return 0


def cmd_show(args: argparse.Namespace) -> int:
    slug = (args.slug or "").strip()
    try:
        _path, text, _fm, _body = _load_file(slug)
    except FileNotFoundError as exc:
        print(json.dumps({"error": str(exc)}), file=sys.stderr)
        return 1
    print(text)
    return 0


def cmd_status(args: argparse.Namespace) -> int:
    slug = (args.slug or "").strip()
    new_status = (args.status or "").strip().lower()
    if new_status not in STATUSES:
        print(json.dumps({"error": f"invalid status '{new_status}' — use active/paused/done"}), file=sys.stderr)
        return 1

    try:
        path, text, fm_yaml, body = _load_file(slug)
    except FileNotFoundError as exc:
        print(json.dumps({"error": str(exc)}), file=sys.stderr)
        return 1

    if not fm_yaml:
        print(json.dumps({"error": "no frontmatter found"}), file=sys.stderr)
        return 1

    frontmatter = yaml.safe_load(fm_yaml) or {}
    frontmatter["status"] = new_status
    _write_file(path, frontmatter, body)
    print(json.dumps({"updated": {"slug": slug, "status": new_status}}, ensure_ascii=False))
    return 0


# ---------------------------------------------------------------------------
# Main
# ---------------------------------------------------------------------------

def main() -> int:
    parser = argparse.ArgumentParser(description="Project file backend")
    sub = parser.add_subparsers(dest="command", required=True)

    p_add = sub.add_parser("add", help="Create a new project")
    p_add.add_argument("name", help="Project name")
    p_add.add_argument("--priority", default="medium", help="Priority: high/medium/low")

    sub.add_parser("list", help="List active projects")

    p_show = sub.add_parser("show", help="Show full project file")
    p_show.add_argument("slug", help="Project slug")

    p_status = sub.add_parser("status", help="Change project status")
    p_status.add_argument("slug", help="Project slug")
    p_status.add_argument("status", help="New status: active/paused/done")

    args = parser.parse_args()
    dispatch = {"add": cmd_add, "list": cmd_list, "show": cmd_show, "status": cmd_status}
    return dispatch[args.command](args)


if __name__ == "__main__":
    sys.exit(main())