#!/usr/bin/env python3
"""Install generated OpenCode artifacts into the user's OpenCode config directory."""

from __future__ import annotations

import argparse
import os
from dataclasses import dataclass, field
from pathlib import Path

REPO_ROOT = Path(__file__).resolve().parent.parent
GENERATED_ROOT = REPO_ROOT / ".opencode"
ARTIFACT_GLOBS = {
    "agents": "*.md",
    "commands": "*.md",
    "skills": "*",
}


@dataclass
class InstallReport:
    linked: int = 0
    unchanged: int = 0
    removed: int = 0
    skipped: int = 0
    errors: list[str] = field(default_factory=list)

    @property
    def ok(self) -> bool:
        return not self.errors


def default_config_dir(env: dict[str, str] | None = None) -> Path:
    env = env or os.environ
    if env.get("OPENCODE_CONFIG_DIR"):
        return Path(env["OPENCODE_CONFIG_DIR"]).expanduser()
    if env.get("XDG_CONFIG_HOME"):
        return Path(env["XDG_CONFIG_HOME"]).expanduser() / "opencode"
    return Path.home() / ".config" / "opencode"


def _is_relative_to(child: Path, parent: Path) -> bool:
    try:
        child.resolve(strict=False).relative_to(parent.resolve(strict=False))
    except ValueError:
        return False
    return True


def _generated_artifacts(repo_root: Path) -> list[tuple[str, Path]]:
    generated_root = repo_root / ".opencode"
    artifacts: list[tuple[str, Path]] = []
    for subdir, pattern in ARTIFACT_GLOBS.items():
        source_dir = generated_root / subdir
        if not source_dir.is_dir():
            raise FileNotFoundError(
                f"{source_dir} does not exist; run `make generate HARNESS=opencode` first"
            )
        for src in sorted(source_dir.glob(pattern)):
            if subdir == "skills" and not src.is_dir():
                continue
            if subdir != "skills" and not src.is_file():
                continue
            artifacts.append((subdir, src.resolve()))
    return artifacts


def _link_one(src: Path, dst: Path, *, force: bool, report: InstallReport) -> None:
    if dst.is_symlink():
        if dst.resolve(strict=False) == src:
            report.unchanged += 1
            return
        if not force:
            report.errors.append(
                f"{dst} already exists as a symlink to {dst.resolve(strict=False)}; "
                "rerun with FORCE=1 to replace symlink conflicts"
            )
            return
        dst.unlink()
    elif dst.exists():
        report.errors.append(f"{dst} already exists and is not a symlink; refusing to overwrite")
        return

    dst.parent.mkdir(parents=True, exist_ok=True)
    dst.symlink_to(src, target_is_directory=src.is_dir())
    report.linked += 1


def install(
    *,
    repo_root: Path = REPO_ROOT,
    config_dir: Path | None = None,
    force: bool = False,
) -> InstallReport:
    config_dir = (config_dir or default_config_dir()).expanduser()
    report = InstallReport()
    try:
        artifacts = _generated_artifacts(repo_root)
    except FileNotFoundError as exc:
        report.errors.append(str(exc))
        return report

    for subdir, src in artifacts:
        dst = config_dir / subdir / src.name
        _link_one(src, dst, force=force, report=report)
    return report


def uninstall(
    *,
    repo_root: Path = REPO_ROOT,
    config_dir: Path | None = None,
) -> InstallReport:
    config_dir = (config_dir or default_config_dir()).expanduser()
    generated_root = (repo_root / ".opencode").resolve(strict=False)
    report = InstallReport()

    for subdir in ARTIFACT_GLOBS:
        target_dir = config_dir / subdir
        if not target_dir.is_dir():
            continue
        for dst in sorted(target_dir.iterdir()):
            if not dst.is_symlink():
                report.skipped += 1
                continue
            target = dst.resolve(strict=False)
            if _is_relative_to(target, generated_root):
                dst.unlink()
                report.removed += 1
            else:
                report.skipped += 1
    return report


def _print_report(action: str, config_dir: Path, report: InstallReport) -> None:
    print(
        f"{action}: config={config_dir} linked={report.linked} unchanged={report.unchanged} "
        f"removed={report.removed} skipped={report.skipped}"
    )
    for error in report.errors:
        print(f"error: {error}")


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("action", choices=("install", "uninstall"))
    parser.add_argument("--config-dir", type=Path, default=None)
    parser.add_argument("--repo-root", type=Path, default=REPO_ROOT)
    parser.add_argument("--force", action="store_true", help="Replace conflicting symlinks only")
    args = parser.parse_args()

    config_dir = (args.config_dir or default_config_dir()).expanduser()
    if args.action == "install":
        report = install(repo_root=args.repo_root, config_dir=config_dir, force=args.force)
    else:
        report = uninstall(repo_root=args.repo_root, config_dir=config_dir)
    _print_report(args.action, config_dir, report)
    return 0 if report.ok else 1


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