#!/usr/bin/env python3
"""Validate that all source trees required by a build config exist."""

import argparse
import sys
import tomllib
from pathlib import Path

PROJECT_ROOT = Path(__file__).resolve().parents[2]
META_PACKAGES = {"libgcc", "libstdcxx"}


def build_lookup():
    lookup = {}
    for root in (PROJECT_ROOT / "recipes", PROJECT_ROOT / "local/recipes"):
        for recipe_toml in root.rglob("recipe.toml"):
            parts = recipe_toml.parts
            if "source" in parts or "target" in parts:
                continue
            package_name = recipe_toml.parent.name
            if package_name not in lookup:
                lookup[package_name] = recipe_toml.parent
    return lookup


def resolve_config(config_path: Path, visited=None):
    if visited is None:
        visited = set()
    config_path = config_path.resolve()
    if config_path in visited:
        return {}
    visited.add(config_path)
    with open(config_path, "rb") as config_file:
        config = tomllib.load(config_file)
    packages = dict(config.get("packages", {}))
    for include in config.get("include", []):
        include_path = config_path.parent / include
        if include_path.exists():
            included_packages = resolve_config(include_path, visited)
            for package_name, package_value in packages.items():
                included_packages[package_name] = package_value
            packages = included_packages
    return packages


def recipe_restore_path(recipe_dir: Path):
    recipes_root = PROJECT_ROOT / "recipes"
    try:
        return recipe_dir.relative_to(recipes_root).as_posix()
    except ValueError:
        return None


def same_as_source_dir(recipe_dir: Path):
    recipe_file = recipe_dir / "recipe.toml"
    if not recipe_file.exists():
        return None
    with open(recipe_file, "rb") as handle:
        recipe = tomllib.load(handle)
    source = recipe.get("source")
    if not isinstance(source, dict):
        return None
    same_as = source.get("same_as")
    if not isinstance(same_as, str) or not same_as:
        return None
    return (recipe_dir / same_as).resolve() / "source"


def parse_args():
    parser = argparse.ArgumentParser()
    parser.add_argument("config", nargs="?", default="redbear-full")
    parser.add_argument("--extra-package", action="append", default=[])
    parser.add_argument("--missing-paths-only", action="store_true")
    parser.add_argument("--release", default="")
    return parser.parse_args()


def main():
    args = parse_args()
    config_path = PROJECT_ROOT / "config" / f"{args.config}.toml"
    if not config_path.exists():
        print(f"Config not found: {config_path}", file=sys.stderr)
        return 1

    lookup = build_lookup()
    packages = resolve_config(config_path)
    requested_packages = dict(packages)
    for package_name in args.extra_package:
        requested_packages.setdefault(package_name, {})

    missing_recipe_paths = []
    missing_entries = []
    present = 0

    for package_name, package_conf in sorted(requested_packages.items()):
        if str(package_conf) == "ignore" or package_name in META_PACKAGES:
            continue
        recipe_dir = lookup.get(package_name)
        if recipe_dir is None:
            missing_entries.append((package_name, None))
            continue
        source_dir = recipe_dir / "source"
        if source_dir.is_dir() and any(source_dir.iterdir()):
            present += 1
            continue
        alias_source_dir = same_as_source_dir(recipe_dir)
        if alias_source_dir is not None and alias_source_dir.is_dir() and any(alias_source_dir.iterdir()):
            present += 1
            continue
        missing_entries.append((package_name, recipe_dir))
        restore_path = recipe_restore_path(recipe_dir)
        if restore_path is not None:
            missing_recipe_paths.append(restore_path)

    if args.missing_paths_only:
        seen = set()
        for recipe_path in missing_recipe_paths:
            if recipe_path not in seen:
                print(recipe_path)
                seen.add(recipe_path)
        return 1 if missing_entries else 0

    print(f"=== Validating source trees for config: {args.config} ===")
    for package_name, recipe_dir in missing_entries:
        if recipe_dir is None:
            print(f"  NOT FOUND: {package_name}")
        else:
            print(f"  MISSING: {recipe_dir.relative_to(PROJECT_ROOT)}")

    total = present + len(missing_entries)
    print(f"\n  Total (config): {total}")
    print(f"  Present:        {present}")
    print(f"  Missing:        {len(missing_entries)}")
    if missing_entries:
        release = args.release or "<release>"
        print(f"\nTo restore:  ./local/scripts/restore-sources.sh --release={release}")
        return 1
    print("All source trees present.")
    return 0


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