#!/usr/bin/env python3
"""
build-hermes.py — Convert claude-skills sources to Hermes-flavour layout.

Reads:  hermes/mapping.yaml
        skills/<name>/             (auto mode)
        hermes/skills/<source>/    (manual mode; `source:` override or /<name>/)

Writes: dist-hermes/<category>/<name>/   (auto + manual)
        dist-hermes/SKIPPED.md           (skip + pending log)

Exits non-zero on:
- skill in skills/ not declared in mapping.skills (forces explicit mapping)
- mode=auto but skills/<name>/ missing
- mode=manual but `source:` directory missing
- a replace-rule `find:` string not found in source SKILL.md

Design: .wiki/concepts/hermes-skills-rollout-design.md
"""

from __future__ import annotations

import argparse
import shutil
import sys
from pathlib import Path
from typing import Any

import yaml


def load_mapping(path: Path) -> dict[str, Any]:
    with path.open(encoding="utf-8") as f:
        return yaml.safe_load(f)


def apply_replace_rules(text: str, rules: list[dict[str, str]], skill_name: str) -> str:
    for rule in rules:
        find = rule["find"]
        replace = rule["replace"]
        if find not in text:
            raise ValueError(
                f"{skill_name}: replace-rule find string not present in SKILL.md: {find!r}"
            )
        text = text.replace(find, replace)
    return text


def copy_tree(src_dir: Path, dst_dir: Path, transform_skill_md: bool, rules: list[dict[str, str]], skill_name: str) -> None:
    if dst_dir.exists():
        shutil.rmtree(dst_dir)
    dst_dir.mkdir(parents=True)
    for src_path in src_dir.rglob("*"):
        rel = src_path.relative_to(src_dir)
        dst_path = dst_dir / rel
        if src_path.is_dir():
            dst_path.mkdir(parents=True, exist_ok=True)
            continue
        dst_path.parent.mkdir(parents=True, exist_ok=True)
        if transform_skill_md and src_path.name == "SKILL.md" and rules:
            text = src_path.read_text(encoding="utf-8")
            text = apply_replace_rules(text, rules, skill_name)
            dst_path.write_text(text, encoding="utf-8")
        else:
            shutil.copyfile(src_path, dst_path)


def write_skill_auto(name: str, entry: dict[str, Any], repo_root: Path, dst_root: Path) -> None:
    src_dir = repo_root / "skills" / name
    if not src_dir.is_dir():
        raise FileNotFoundError(f"auto skill source missing: {src_dir}")
    cat = entry["category"]
    rules = entry.get("replace-rules") or []
    copy_tree(src_dir, dst_root / cat / name, transform_skill_md=True, rules=rules, skill_name=name)


def write_skill_manual(name: str, entry: dict[str, Any], repo_root: Path, dst_root: Path) -> None:
    source = entry.get("source") or f"hermes/skills/{name}"
    src_dir = repo_root / source
    if not src_dir.is_dir():
        raise FileNotFoundError(f"manual skill source missing: {src_dir}")
    cat = entry["category"]
    copy_tree(src_dir, dst_root / cat / name, transform_skill_md=False, rules=[], skill_name=name)


def render_skipped_md(skipped: list[tuple[str, str]], pending: list[tuple[str, dict, str]]) -> str:
    lines: list[str] = [
        "# Skipped Skills",
        "",
        "Auto-generated by `scripts/build-hermes.py` from `hermes/mapping.yaml`.",
        "Do not edit by hand — edit the mapping and re-run the build.",
        "",
        "## Skipped (not applicable to Hermes)",
        "",
    ]
    if skipped:
        for name, reason in sorted(skipped):
            lines.append(f"- **{name}** — {reason}")
    else:
        lines.append("(none)")
    lines.extend(["", "## Pending (deferred to follow-up tasks)", ""])
    if pending:
        for name, intended, reason in sorted(pending):
            tail = ""
            if intended:
                im = intended.get("mode", "?")
                ic = intended.get("category", "?")
                tail = f" → intended: `mode: {im}, category: {ic}`"
            lines.append(f"- **{name}** — {reason}{tail}")
    else:
        lines.append("(none)")
    lines.append("")
    return "\n".join(lines)


def main() -> int:
    parser = argparse.ArgumentParser(description="Convert claude-skills sources to Hermes-flavour layout.")
    parser.add_argument(
        "--repo-root",
        type=Path,
        default=Path(__file__).resolve().parent.parent,
        help="Repo root (default: parent of scripts/)",
    )
    parser.add_argument("--dist", type=Path, default=None, help="Output dir (default: <repo>/dist-hermes)")
    parser.add_argument("--mapping", type=Path, default=None, help="Mapping file (default: <repo>/hermes/mapping.yaml)")
    args = parser.parse_args()

    repo_root: Path = args.repo_root.resolve()
    mapping_path: Path = (args.mapping or (repo_root / "hermes" / "mapping.yaml")).resolve()
    dst_root: Path = (args.dist or (repo_root / "dist-hermes")).resolve()

    mapping = load_mapping(mapping_path)
    skills_map: dict[str, dict[str, Any]] = mapping.get("skills") or {}

    skills_dir = repo_root / "skills"
    fs_skills = sorted(p.name for p in skills_dir.iterdir() if p.is_dir())

    unmapped = [n for n in fs_skills if n not in skills_map]
    if unmapped:
        print(f"ERROR: skills/ has unmapped entries: {unmapped}", file=sys.stderr)
        print(f"Add explicit `mode:` lines for each in {mapping_path.name}.", file=sys.stderr)
        return 1

    counts = {"auto": 0, "manual": 0, "skip": 0, "pending": 0}
    skipped: list[tuple[str, str]] = []
    pending: list[tuple[str, dict, str]] = []

    for name, entry in sorted(skills_map.items()):
        mode = entry.get("mode")
        if mode == "auto":
            write_skill_auto(name, entry, repo_root, dst_root)
        elif mode == "manual":
            write_skill_manual(name, entry, repo_root, dst_root)
        elif mode == "skip":
            skipped.append((name, entry.get("reason", "(no reason)")))
        elif mode == "pending":
            pending.append((name, entry.get("intended") or {}, entry.get("reason", "(no reason)")))
        else:
            print(f"ERROR: unknown mode for {name}: {mode!r}", file=sys.stderr)
            return 1
        counts[mode] += 1

    dst_root.mkdir(parents=True, exist_ok=True)
    (dst_root / "SKIPPED.md").write_text(render_skipped_md(skipped, pending), encoding="utf-8")

    total = sum(counts.values())
    print(f"build-hermes: {total} skills processed")
    print(f"  auto    {counts['auto']:>3}")
    print(f"  manual  {counts['manual']:>3}")
    print(f"  skip    {counts['skip']:>3}")
    print(f"  pending {counts['pending']:>3}")
    print(f"  out: {dst_root}")
    return 0


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