import { readdir, readFile, stat } from "node:fs/promises";
import { join } from "node:path";

/**
 * Walk `packages/<category>/<plugin>/<pkg>/README.md` for the canonical
 * 3-level layout. A README is only included when its sibling `package.json`
 * declares an `@suaveplan/*` workspace package — this skips stale plugin- or
 * category-level READMEs that don't correspond to a real package.
 */
async function findReadmes(dir: string): Promise<string[]> {
    const results: string[] = [];
    const categoryEntries = await readdir(dir, { withFileTypes: true });

    for (const category of categoryEntries) {
        if (!category.isDirectory()) continue;
        if (category.name.startsWith(".")) continue;
        const categoryPath = join(dir, category.name);
        const pluginEntries = await readdir(categoryPath, {
            withFileTypes: true,
        }).catch(() => []);

        for (const plugin of pluginEntries) {
            if (!plugin.isDirectory()) continue;
            if (plugin.name.startsWith(".")) continue;
            const pluginPath = join(categoryPath, plugin.name);
            const pkgEntries = await readdir(pluginPath, {
                withFileTypes: true,
            }).catch(() => []);

            for (const pkg of pkgEntries) {
                if (!pkg.isDirectory()) continue;
                if (pkg.name.startsWith(".")) continue;
                const pkgPath = join(pluginPath, pkg.name);

                // Only count this README if there's a workspace package.json
                // (skips stale plugin-level READMEs left from prior layouts).
                const pkgJsonPath = join(pkgPath, "package.json");
                try {
                    await stat(pkgJsonPath);
                } catch {
                    continue;
                }

                const readmePath = join(pkgPath, "README.md");
                try {
                    await readFile(readmePath);
                    results.push(readmePath);
                } catch {
                    // README.md doesn't exist, skip
                }
            }
        }
    }

    return results;
}

async function main() {
    const readmePaths = await findReadmes("./packages");
    const mismatches: string[] = [];

    for (const path of readmePaths) {
        const content = await readFile(path, "utf-8");
        const firstLine = content.split(/\r?\n/)[0] ?? "";
        if (!/^#\s@[^\s]+\s/.test(firstLine)) {
            mismatches.push(path);
        }
    }

    if (mismatches.length === 0) {
        console.log("All README.md files start with '# @' on the first line.");
    } else {
        console.log(
            `Found ${mismatches.length} README.md file(s) without '# @' as the first line:`
        );
        for (const path of mismatches) {
            console.log(`  ${path}`);
        }
        process.exit(1);
    }
}

main().catch((err) => {
    console.error(err);
    process.exit(1);
});