<?php

/* Copyright (C) 2026 Moko Consulting <hello@mokoconsulting.tech>
 *
 * This file is part of a Moko Consulting project.
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 * FILE INFORMATION
 * DEFGROUP: MokoPlatform.Enterprise
 * INGROUP: MokoPlatform.Lib
 * REPO: https://git.mokoconsulting.tech/MokoConsulting/mokoplatform
 * PATH: /lib/Enterprise/SourceResolver.php
 * BRIEF: Resolve the root-level source directory across repos (source/, src/, htdocs/)
 */

declare(strict_types=1);

namespace MokoCli;

/**
 * Source Directory Resolver
 *
 * Provides a single, consistent fallback chain for locating the root-level
 * source directory in any MokoCli repository. The preferred directory
 * is `source/`, with legacy `src/` and `htdocs/` as fallbacks.
 *
 * This class exists because Joomla extensions use `src/` for namespace
 * autoloading (e.g. administrator/components/com_foo/src/). Renaming our
 * root-level source directory to `source/` avoids that collision. During
 * the transition period, repos may still use `src/`, so all tooling must
 * check both.
 *
 * Usage:
 *   $dir  = SourceResolver::resolve($repoRoot);          // 'source', 'src', or 'htdocs'
 *   $abs  = SourceResolver::resolveAbsolute($repoRoot);   // full path or null
 *   $xmls = SourceResolver::globSource($repoRoot, '*.xml'); // glob under first match
 *   $path = SourceResolver::findUnderSource($repoRoot, 'core/modules'); // subpath lookup
 *
 * @since 09.02.00
 */
class SourceResolver
{
    /**
     * Ordered candidate directories. source/ is preferred, src/ is legacy fallback.
     *
     * When the migration is complete and all repos use source/, the 'src'
     * entry can be removed from this list.
     *
     * @var string[]
     */
    private const CANDIDATES = ['source', 'src', 'htdocs'];

    /** Cache of API-resolved entry points keyed by "org/repo". */
    private static array $apiCache = [];

    /**
     * Resolve the source directory name for a repository root.
     *
     * Resolution order:
     *   1. Gitea Manifest API `entry_point` (when GA_TOKEN/GITEA_TOKEN + GITHUB_REPOSITORY are set)
     *   2. First candidate directory that exists on the filesystem
     *   3. 'source' as the default (e.g. for new repos being scaffolded)
     *
     * @param string $root Absolute path to the repository root.
     * @return string Directory name (e.g. 'source', 'src', 'htdocs').
     */
    public static function resolve(string $root): string
    {
        // Try API first (CI environments where token + repo are available)
        $apiResult = self::resolveFromApi($root);
        if ($apiResult !== null) {
            return $apiResult;
        }

        // Filesystem fallback
        foreach (self::CANDIDATES as $candidate) {
            if (is_dir("{$root}/{$candidate}")) {
                return $candidate;
            }
        }

        return 'source';
    }

    /**
     * Query the MokoGitea Manifest API for the entry_point field.
     *
     * Only attempts the call when GA_TOKEN or GITEA_TOKEN is set. Results are
     * cached per org/repo for the lifetime of the process.
     *
     * @param string $root Repository root (used to derive org/repo from git remote).
     * @return string|null Directory name from entry_point, or null if unavailable.
     */
    public static function resolveFromApi(string $root): ?string
    {
        $token = getenv('GA_TOKEN') ?: getenv('GITEA_TOKEN') ?: '';
        if ($token === '') {
            return null;
        }

        [$org, $repo] = self::resolveOrgRepo($root);
        if ($org === '' || $repo === '') {
            return null;
        }

        $cacheKey = "{$org}/{$repo}";
        if (array_key_exists($cacheKey, self::$apiCache)) {
            return self::$apiCache[$cacheKey];
        }

        $baseUrl = rtrim(getenv('GITEA_URL') ?: 'https://git.mokoconsulting.tech', '/');
        $url = "{$baseUrl}/api/v1/repos/{$org}/{$repo}/manifest";

        $ctx = stream_context_create([
            'http' => [
                'header'        => "Authorization: token {$token}\r\nAccept: application/json\r\n",
                'timeout'       => 5,
                'ignore_errors' => true,
            ],
        ]);

        $body = @file_get_contents($url, false, $ctx);
        if ($body === false) {
            self::$apiCache[$cacheKey] = null;
            return null;
        }

        $status = 0;
        if (isset($http_response_header[0])) {
            preg_match('/\d{3}/', $http_response_header[0], $m);
            $status = (int) ($m[0] ?? 0);
        }
        if ($status < 200 || $status >= 300) {
            self::$apiCache[$cacheKey] = null;
            return null;
        }

        $data = json_decode($body, true);
        $entryPoint = $data['entry_point'] ?? '';

        // Normalize: "source/" → "source", "cli/" → "cli"
        $result = ($entryPoint !== '') ? rtrim($entryPoint, '/') : null;

        self::$apiCache[$cacheKey] = $result;
        return $result;
    }

    /**
     * Resolve org/repo from GITHUB_REPOSITORY env or git remote.
     *
     * @return array{0: string, 1: string}
     */
    private static function resolveOrgRepo(string $root): array
    {
        $envRepo = getenv('GITHUB_REPOSITORY') ?: '';
        if ($envRepo !== '' && str_contains($envRepo, '/')) {
            return explode('/', $envRepo, 2);
        }

        $remoteUrl = trim((string) @shell_exec(
            'git -C ' . escapeshellarg($root) . ' remote get-url origin 2>/dev/null'
        ));

        if ($remoteUrl !== '' && preg_match('#[/:]([^/]+)/([^/]+?)(?:\.git)?$#', $remoteUrl, $m)) {
            return [$m[1], $m[2]];
        }

        return ['', ''];
    }

    /**
     * Resolve the source directory as an absolute path.
     *
     * @param string $root Absolute path to the repository root.
     * @return string|null Absolute path to the source directory, or null if none exists.
     */
    public static function resolveAbsolute(string $root): ?string
    {
        foreach (self::CANDIDATES as $candidate) {
            $path = "{$root}/{$candidate}";
            if (is_dir($path)) {
                return $path;
            }
        }

        return null;
    }

    /**
     * Glob for files under the source directory.
     *
     * Checks each candidate directory in order and returns matches from the
     * first candidate that produces results. This replaces patterns like:
     *
     *   glob("{$root}/src/*.xml")
     *
     * With the backwards-compatible:
     *
     *   SourceResolver::globSource($root, '*.xml')
     *
     * @param string $root    Absolute path to the repository root.
     * @param string $pattern Glob pattern relative to the source directory.
     * @return string[] Matched file paths (may be empty).
     */
    public static function globSource(string $root, string $pattern): array
    {
        foreach (self::CANDIDATES as $candidate) {
            $dir = "{$root}/{$candidate}";
            if (!is_dir($dir)) {
                continue;
            }
            $matches = glob("{$dir}/{$pattern}") ?: [];
            if ($matches !== []) {
                return $matches;
            }
        }

        return [];
    }

    /**
     * Find a subpath under any source directory candidate.
     *
     * Useful for locating platform-specific subdirectories like
     * `core/modules/` (Dolibarr) or `media/templates/` (Joomla client themes)
     * regardless of whether the repo uses `source/` or `src/`.
     *
     * @param string $root    Absolute path to the repository root.
     * @param string $subpath Relative path to look for (e.g. 'core/modules', 'index.ts').
     * @return string|null    Absolute path if found, null otherwise.
     */
    public static function findUnderSource(string $root, string $subpath): ?string
    {
        foreach (self::CANDIDATES as $candidate) {
            $full = "{$root}/{$candidate}/{$subpath}";
            if (file_exists($full) || is_dir($full)) {
                return $full;
            }
        }

        return null;
    }

    /**
     * Get the ordered list of candidate directory names.
     *
     * Useful for workflows or scripts that need to iterate candidates
     * themselves (e.g. building find/grep patterns).
     *
     * @return string[]
     */
    public static function getCandidates(): array
    {
        return self::CANDIDATES;
    }

    /**
     * Check whether the resolved source directory is a legacy name (src/).
     *
     * @param string $root Absolute path to the repository root.
     * @return bool True if the repo uses src/ instead of source/.
     */
    public static function isLegacy(string $root): bool
    {
        $resolved = self::resolve($root);

        return $resolved === 'src';
    }

    /**
     * Emit a deprecation warning to stderr if the repo still uses src/.
     *
     * CLI tools should call this after resolving the source directory so
     * that maintainers know to rename src/ → source/.
     *
     * @param string $root Absolute path to the repository root.
     */
    public static function warnIfLegacy(string $root): void
    {
        if (self::isLegacy($root)) {
            fwrite(STDERR, "⚠  WARNING: This repo uses src/ which is deprecated. Rename to source/ per MokoCli conventions.\n");
        }
    }
}