<?php

declare(strict_types=1);

namespace LIT\MCP\Integrations\Divi\Release;

use RuntimeException;

defined('ABSPATH') || exit;

/**
 * The expected fingerprints (fingerprints.json, shipped with the plugin): the source fingerprint of every mirror under
 * its ID, and the signature fingerprint of every Divi call under "sig:<symbol>" (SignatureFingerprint) – plus the
 * reference sources of the mirrors (tests/Fixtures/divi/reference/<id>.txt, development only – not in the plugin
 * package). Written by wp lit-mcp divi-check --update-reference.
 */
final class DiviReference
{
    public const FILE = __DIR__ . '/fingerprints.json';

    /** Key prefix of the signature fingerprints; no mirror ID starts with it. */
    public const SIGNATURE_PREFIX = 'sig:';

    /**
     * @return array<string, string> Mirror ID or "sig:<symbol>" => sha256, sorted by key; [] when the file is
     *         missing or broken.
     */
    public static function expected(?string $file = null): array
    {
        $file ??= self::FILE;
        // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents -- local plugin file.
        $raw = is_file($file) && is_readable($file) ? file_get_contents($file) : false;
        $data = is_string($raw) ? json_decode($raw, true) : null;
        if (! is_array($data)) {
            return [];
        }

        $expected = [];
        foreach ($data as $id => $hash) {
            if (is_string($id) && is_string($hash)) {
                $expected[$id] = $hash;
            }
        }
        ksort($expected);

        return $expected;
    }

    /**
     * @param array<string, string> $hashes Mirror ID or "sig:<symbol>" => sha256; written sorted by key.
     * @throws RuntimeException
     */
    public static function writeExpected(array $hashes, ?string $file = null): void
    {
        ksort($hashes);
        // phpcs:ignore WordPress.WP.AlternativeFunctions.json_encode_json_encode -- pure PHP, no WordPress.
        $json = json_encode($hashes, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);
        // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_file_put_contents -- dev fixture.
        if (! is_string($json) || file_put_contents($file ?? self::FILE, $json . "\n") === false) {
            throw new RuntimeException('fingerprints.json not written');
        }
    }

    /** The key of $call's signature fingerprint: "sig:" and the symbol without a leading backslash. */
    public static function signatureKey(Call $call): string
    {
        return self::SIGNATURE_PREFIX . ltrim($call->symbol, '\\');
    }

    /**
     * Signature fingerprints of the calls in the running PHP process (Divi loaded).
     *
     * @param list<Call>|null $calls null = DiviAdapters::calls().
     * @return array<string, string> "sig:<symbol>" => sha256, sorted by key.
     * @throws RuntimeException When a symbol is not loaded.
     */
    public static function currentSignatures(?array $calls = null): array
    {
        $signatures = [];
        foreach ($calls ?? DiviAdapters::calls() as $call) {
            $hash = SignatureFingerprint::of($call);
            if ($hash === null) {
                throw new RuntimeException(sprintf('signature of %s: symbol is not loaded', $call->label()));
            }
            $signatures[self::signatureKey($call)] = $hash;
        }
        ksort($signatures);

        return $signatures;
    }

    /** tests/Fixtures/divi/reference of a development checkout; null in an installed plugin. */
    public static function sourceDir(): ?string
    {
        $dir = dirname(__DIR__, 4) . '/tests/Fixtures/divi/reference';

        return is_dir($dir) ? $dir : null;
    }

    public static function readSource(string $id, string $dir): ?string
    {
        $file = $dir . '/' . $id . '.txt';
        // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents -- local dev fixture.
        $source = is_file($file) ? file_get_contents($file) : false;

        return is_string($source) ? $source : null;
    }

    /** @throws RuntimeException */
    public static function writeSource(string $id, string $source, string $dir): void
    {
        // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_file_put_contents -- dev fixture.
        if (file_put_contents($dir . '/' . $id . '.txt', $source . "\n") === false) {
            throw new RuntimeException(sprintf('reference source %s not written', $id));
        }
    }

    /**
     * Fingerprints of every mirror in the installed Divi.
     *
     * @return array<string, SourceFingerprint>
     * @throws RuntimeException When a mirrored function cannot be read.
     */
    public static function current(string $themeDir): array
    {
        $prints = [];
        foreach (DiviAdapters::mirrors() as $mirror) {
            $file = $themeDir . '/' . $mirror->file;
            $prints[$mirror->id] = SourceFingerprint::of($file, $mirror->function, $mirror->class);
        }

        return $prints;
    }
}