"""Canonical Codex package directory layout."""

import json
import shutil
import stat
from pathlib import Path

from .targets import PackageInputs
from .targets import PackageVariant
from .targets import TargetSpec
from .zsh import ZSH_RESOURCE_PATH


LAYOUT_VERSION = 1


def prepare_package_dir(package_dir: Path, *, force: bool) -> None:
    if package_dir.exists():
        if not package_dir.is_dir():
            raise RuntimeError(
                f"Package output exists and is not a directory: {package_dir}"
            )
        if any(package_dir.iterdir()):
            if not force:
                raise RuntimeError(
                    f"Package output directory is not empty: {package_dir}. "
                    "Pass --force to replace it."
                )
            shutil.rmtree(package_dir)

    package_dir.mkdir(parents=True, exist_ok=True)


def build_package_dir(
    package_dir: Path,
    version: str,
    variant: PackageVariant,
    spec: TargetSpec,
    inputs: PackageInputs,
) -> None:
    bin_dir = package_dir / "bin"
    resources_dir = package_dir / "codex-resources"
    path_dir = package_dir / "codex-path"
    bin_dir.mkdir()
    resources_dir.mkdir()
    path_dir.mkdir()

    entrypoint_name = variant.entrypoint_name(spec)
    copy_executable(
        inputs.entrypoint_bin,
        bin_dir / entrypoint_name,
        is_windows=spec.is_windows,
    )
    copy_executable(inputs.rg_bin, path_dir / spec.rg_name, is_windows=spec.is_windows)

    if inputs.zsh_bin is not None:
        copy_executable(
            inputs.zsh_bin,
            resources_dir / ZSH_RESOURCE_PATH,
            is_windows=False,
        )

    if inputs.bwrap_bin is not None:
        copy_executable(inputs.bwrap_bin, resources_dir / "bwrap", is_windows=False)

    if inputs.codex_command_runner_bin is not None:
        copy_executable(
            inputs.codex_command_runner_bin,
            resources_dir / "codex-command-runner.exe",
            is_windows=True,
        )

    if inputs.codex_windows_sandbox_setup_bin is not None:
        copy_executable(
            inputs.codex_windows_sandbox_setup_bin,
            resources_dir / "codex-windows-sandbox-setup.exe",
            is_windows=True,
        )

    metadata = {
        "layoutVersion": LAYOUT_VERSION,
        "version": version,
        "target": spec.target,
        "variant": variant.name,
        "entrypoint": f"bin/{entrypoint_name}",
        "resourcesDir": "codex-resources",
        "pathDir": "codex-path",
    }
    write_json(package_dir / "codex-package.json", metadata)


def validate_package_dir(
    package_dir: Path,
    variant: PackageVariant,
    spec: TargetSpec,
    *,
    include_zsh: bool,
) -> None:
    required_dirs = [
        Path("bin"),
        Path("codex-resources"),
        Path("codex-path"),
    ]
    for relative_dir in required_dirs:
        path = package_dir / relative_dir
        if not path.is_dir():
            raise RuntimeError(f"Missing package directory: {relative_dir}")

    metadata_path = package_dir / "codex-package.json"
    if not metadata_path.is_file():
        raise RuntimeError("Missing package metadata: codex-package.json")

    with open(metadata_path, encoding="utf-8") as fh:
        metadata = json.load(fh)

    expected_metadata = {
        "layoutVersion": LAYOUT_VERSION,
        "target": spec.target,
        "variant": variant.name,
        "entrypoint": f"bin/{variant.entrypoint_name(spec)}",
        "resourcesDir": "codex-resources",
        "pathDir": "codex-path",
    }
    for key, expected in expected_metadata.items():
        actual = metadata.get(key)
        if actual != expected:
            raise RuntimeError(
                f"Invalid package metadata field {key!r}: expected {expected!r}, got {actual!r}"
            )

    required_files = [
        Path("bin") / variant.entrypoint_name(spec),
        Path("codex-path") / spec.rg_name,
    ]
    executable_files = list(required_files)

    if include_zsh:
        zsh_path = Path("codex-resources") / ZSH_RESOURCE_PATH
        required_files.append(zsh_path)
        executable_files.append(zsh_path)

    if spec.is_linux:
        required_files.append(Path("codex-resources") / "bwrap")
        executable_files.append(Path("codex-resources") / "bwrap")

    if spec.is_windows:
        required_files.extend(
            [
                Path("codex-resources") / "codex-command-runner.exe",
                Path("codex-resources") / "codex-windows-sandbox-setup.exe",
            ]
        )

    for relative_file in required_files:
        path = package_dir / relative_file
        if not path.is_file():
            raise RuntimeError(f"Missing package file: {relative_file}")

    if not spec.is_windows:
        for relative_file in executable_files:
            path = package_dir / relative_file
            if not is_executable(path):
                raise RuntimeError(f"Package file is not executable: {relative_file}")


def copy_executable(src: Path, dest: Path, *, is_windows: bool) -> None:
    dest.parent.mkdir(parents=True, exist_ok=True)
    shutil.copyfile(src, dest)
    if not is_windows:
        mode = dest.stat().st_mode
        dest.chmod(mode | stat.S_IXUSR | stat.S_IXGRP | stat.S_IXOTH)


def write_json(path: Path, value: object) -> None:
    with open(path, "w", encoding="utf-8") as out:
        json.dump(value, out, indent=2)
        out.write("\n")


def is_executable(path: Path) -> bool:
    return bool(path.stat().st_mode & stat.S_IXUSR)
