#!/usr/bin/env python3
# hf-skills — Download and install HF CLI skills for AI assistants
#
# Usage:
#   hf tool run skills --claude                 # Install for Claude (project-level)
#   hf tool run skills --claude --global        # Install for Claude (user-level)
#   hf tool run skills --claude --codex         # Install for multiple agents
#   hf tool run skills --dest=~/my-skills       # Install to a custom directory
#   hf tool run skills --claude --force         # Overwrite existing

import argparse
import os
import shutil
import sys
from pathlib import Path
from urllib.request import Request, urlopen


SKILL_ID = "hf-cli"

_GITHUB_RAW_BASE = "https://raw.githubusercontent.com/huggingface/huggingface_hub/main/docs/source/en"
_SKILL_MD_URL = f"{_GITHUB_RAW_BASE}/guides/cli.md"
_REFERENCE_URL = f"{_GITHUB_RAW_BASE}/package_reference/cli.md"

_SKILL_YAML_PREFIX = """\
---
name: hf-cli
description: >
  Hugging Face Hub CLI (`hf`) for downloading, uploading, and managing
  repositories, models, datasets, and Spaces on the Hugging Face Hub.
---

The Hugging Face Hub CLI tool `hf` is available. IMPORTANT: The `hf` command replaces the deprecated `huggingface_cli` command.

Use `hf --help` to view available functions. Note that auth commands are now all under `hf auth` e.g. `hf auth whoami`.
"""

CENTRAL_LOCAL = Path(".agents/skills")
CENTRAL_GLOBAL = Path("~/.agents/skills")

GLOBAL_TARGETS = {
    "codex": Path("~/.codex/skills"),
    "claude": Path("~/.claude/skills"),
    "opencode": Path("~/.config/opencode/skills"),
}

LOCAL_TARGETS = {
    "codex": Path(".codex/skills"),
    "claude": Path(".claude/skills"),
    "opencode": Path(".opencode/skills"),
}


def _download(url):
    req = Request(url, headers={"User-Agent": "hf-skills/1.0"})
    with urlopen(req) as resp:
        return resp.read().decode("utf-8")


def _remove_existing(path, force):
    if not (path.exists() or path.is_symlink()):
        return
    if not force:
        print(f"Skill already exists at {path}.\nRe-run with --force to overwrite.", file=sys.stderr)
        sys.exit(1)
    if path.is_dir() and not path.is_symlink():
        shutil.rmtree(path)
    else:
        path.unlink()


def _install_to(skills_dir, force):
    skills_dir = skills_dir.expanduser().resolve()
    skills_dir.mkdir(parents=True, exist_ok=True)
    dest = skills_dir / SKILL_ID

    _remove_existing(dest, force)
    dest.mkdir()

    skill_content = _download(_SKILL_MD_URL)
    (dest / "SKILL.md").write_text(_SKILL_YAML_PREFIX + skill_content, encoding="utf-8")

    ref_dir = dest / "references"
    ref_dir.mkdir()
    ref_content = _download(_REFERENCE_URL)
    (ref_dir / "cli.md").write_text(ref_content, encoding="utf-8")

    return dest


def _create_symlink(agent_skills_dir, central_skill_path, force):
    agent_skills_dir = agent_skills_dir.expanduser().resolve()
    agent_skills_dir.mkdir(parents=True, exist_ok=True)
    link_path = agent_skills_dir / SKILL_ID

    _remove_existing(link_path, force)
    link_path.symlink_to(os.path.relpath(central_skill_path, agent_skills_dir))

    return link_path


def main():
    parser = argparse.ArgumentParser(
        description="Download and install HF CLI skills for AI assistants.",
        epilog="Examples:\n"
        "  hf tool run skills --claude\n"
        "  hf tool run skills --claude --global\n"
        "  hf tool run skills --codex --opencode\n"
        "  hf tool run skills --dest ~/my-skills\n",
        formatter_class=argparse.RawDescriptionHelpFormatter,
    )
    parser.add_argument("--claude", action="store_true", help="Install for Claude")
    parser.add_argument("--codex", action="store_true", help="Install for Codex")
    parser.add_argument("--opencode", action="store_true", help="Install for OpenCode")
    parser.add_argument("--global", dest="global_", action="store_true", help="Install globally (user-level)")
    parser.add_argument("--dest", type=Path, help="Install into a custom destination directory")
    parser.add_argument("--force", action="store_true", help="Overwrite existing skills")
    args = parser.parse_args()

    if not (args.claude or args.codex or args.opencode or args.dest):
        parser.error("Pick a destination via --claude, --codex, --opencode, or --dest.")

    if args.dest:
        if args.claude or args.codex or args.opencode or args.global_:
            print("--dest cannot be combined with --claude, --codex, --opencode, or --global.", file=sys.stderr)
            sys.exit(1)
        skill_dest = _install_to(args.dest, args.force)
        print(f"Installed '{SKILL_ID}' to {skill_dest}")
        return

    targets_dict = GLOBAL_TARGETS if args.global_ else LOCAL_TARGETS
    agent_targets = []
    if args.claude:
        agent_targets.append(targets_dict["claude"])
    if args.codex:
        agent_targets.append(targets_dict["codex"])
    if args.opencode:
        agent_targets.append(targets_dict["opencode"])

    central_path = CENTRAL_GLOBAL if args.global_ else CENTRAL_LOCAL
    central_skill_path = _install_to(central_path, args.force)
    print(f"Installed '{SKILL_ID}' to central location: {central_skill_path}")

    for agent_target in agent_targets:
        link_path = _create_symlink(agent_target, central_skill_path, args.force)
        print(f"Created symlink: {link_path}")


if __name__ == "__main__":
    main()