<?php

namespace App\Commands;

use CodeIgniter\CLI\BaseCommand;
use CodeIgniter\CLI\CLI;

class MigrateLocalFilesToS3 extends BaseCommand
{
    protected $group = 'Storage';
    protected $name = 'storage:migrate-local-to-s3';
    protected $description = 'One-time phased migration of local uploaded files to S3 using FileStorageService.';
    protected $usage = 'storage:migrate-local-to-s3 [--module writable_uploads|<folder_name>|insurer_claim_form|all] [--limit 500] [--offset 0] [--execute]';
    protected $options = [
        '--module' => 'Target module/folder (default: writable_uploads). Use writable_uploads for all writable/uploads/* folders.',
        '--limit' => 'Max files per run (default: 500).',
        '--offset' => 'Start offset for phased batches (default: 0).',
        '--execute' => 'Actually upload files. Without this flag, command runs in dry-run mode.',
    ];

    /**
     * @var array<string, string>
     */
    private array $staticPaths = [
        'insurer_claim_form' => WRITEPATH . 'insurer_claim_form',
    ];

    public function run(array $params)
    {
        $moduleOpt = strtolower((string) (CLI::getOption('module') ?? 'writable_uploads'));
        $execute = CLI::getOption('execute') !== null;
        $dryRun = !$execute;
        $limit = max(1, (int) (CLI::getOption('limit') ?? 500));
        $offset = max(0, (int) (CLI::getOption('offset') ?? 0));
        $modulePaths = $this->buildModulePaths();

        $selectedModules = $this->resolveModules($moduleOpt, $modulePaths);
        if ($selectedModules === []) {
            CLI::error('Invalid --module value. Allowed: writable_uploads, ' . implode(', ', array_keys($modulePaths)) . ', all');
            return;
        }

        $storage = \Config\Services::getFileStorageService(false);
        if (!$storage->usesS3()) {
            CLI::error('FileStorageService is not in S3 mode. Set FILE_STORAGE_DRIVER=s3 before migration.');
            return;
        }

        CLI::write($dryRun ? 'Running in DRY-RUN mode (no uploads).' : 'Running in EXECUTE mode (uploads enabled).', 'yellow');
        CLI::write('Target bucket: ' . ($storage->getBucket() ?? 'N/A'), 'cyan');
        CLI::newLine();

        $totals = [
            'seen' => 0,
            'uploaded' => 0,
            'skipped_exists' => 0,
            'skipped_missing' => 0,
            'failed' => 0,
        ];

        foreach ($selectedModules as $module) {
            $path = $modulePaths[$module];
            CLI::write("Module: {$module}", 'green');
            CLI::write("Path: {$path}");

            if (!is_dir($path)) {
                CLI::write('  - Skipped: folder does not exist', 'yellow');
                $totals['skipped_missing']++;
                CLI::newLine();
                continue;
            }

            $files = $this->listFiles($path);
            $files = array_slice($files, $offset, $limit);
            CLI::write('  - Files in batch: ' . count($files));

            foreach ($files as $fullPath) {
                $totals['seen']++;
                $fileName = basename($fullPath);

                if (!is_file($fullPath)) {
                    $totals['skipped_missing']++;
                    CLI::write("  - Missing: {$fileName}", 'yellow');
                    continue;
                }

                $alreadyExists = $storage->exists($path, $fileName);
                if ($alreadyExists) {
                    $totals['skipped_exists']++;
                    CLI::write("  - Exists in S3, skipped: {$fileName}", 'yellow');
                    continue;
                }

                if ($dryRun) {
                    CLI::write("  - [dry-run] Would upload: {$fileName}");
                    continue;
                }

                $result = $storage->upload($fullPath, $path, $fileName);
                if ($result['success'] ?? false) {
                    $totals['uploaded']++;
                    CLI::write("  - Uploaded: {$fileName}", 'green');
                } else {
                    $totals['failed']++;
                    CLI::write("  - Failed: {$fileName} | " . ($result['message'] ?? 'unknown error'), 'red');
                }
            }

            CLI::newLine();
        }

        CLI::write('Migration summary', 'cyan');
        CLI::write('  Seen: ' . $totals['seen']);
        CLI::write('  Uploaded: ' . $totals['uploaded'], $totals['uploaded'] > 0 ? 'green' : 'white');
        CLI::write('  Skipped (already in S3): ' . $totals['skipped_exists'], 'yellow');
        CLI::write('  Skipped (missing/invalid): ' . $totals['skipped_missing'], 'yellow');
        CLI::write('  Failed: ' . $totals['failed'], $totals['failed'] > 0 ? 'red' : 'white');

        if ($dryRun) {
            CLI::newLine();
            CLI::write('Dry-run complete. Re-run with --execute to perform uploads.', 'yellow');
        }
    }

    /**
     * @return array<int, string>
     */
    private function resolveModules(string $moduleOpt, array $modulePaths): array
    {
        if ($moduleOpt === 'all') {
            return array_keys($modulePaths);
        }

        if ($moduleOpt === 'writable_uploads') {
            $uploadRoot = rtrim(WRITEPATH, '/\\') . DIRECTORY_SEPARATOR . 'uploads' . DIRECTORY_SEPARATOR;
            $modules = [];
            foreach ($modulePaths as $module => $path) {
                $normalized = str_replace('\\', '/', $path);
                $normalizedRoot = str_replace('\\', '/', $uploadRoot);
                if (strpos($normalized, rtrim($normalizedRoot, '/')) === 0) {
                    $modules[] = $module;
                }
            }

            return $modules;
        }

        $raw = array_filter(array_map('trim', explode(',', $moduleOpt)));
        $valid = [];
        foreach ($raw as $module) {
            if (array_key_exists($module, $modulePaths)) {
                $valid[] = $module;
            }
        }

        return array_values(array_unique($valid));
    }

    /**
     * Build migratable paths:
     * - all direct subfolders in writable/uploads
     * - additional static paths (outside writable/uploads)
     *
     * @return array<string, string>
     */
    private function buildModulePaths(): array
    {
        $paths = [];
        $uploadRoot = rtrim(WRITEPATH, '/\\') . DIRECTORY_SEPARATOR . 'uploads';
        $entries = @scandir($uploadRoot);

        if (is_array($entries)) {
            foreach ($entries as $entry) {
                if ($entry === '.' || $entry === '..') {
                    continue;
                }

                $fullPath = $uploadRoot . DIRECTORY_SEPARATOR . $entry;
                if (is_dir($fullPath)) {
                    $paths[strtolower($entry)] = $fullPath;
                }
            }
        }

        foreach ($this->staticPaths as $key => $path) {
            $paths[$key] = $path;
        }

        ksort($paths);
        return $paths;
    }

    /**
     * @return array<int, string>
     */
    private function listFiles(string $path): array
    {
        $entries = @scandir($path);
        if (!is_array($entries)) {
            return [];
        }

        $files = [];
        foreach ($entries as $entry) {
            if ($entry === '.' || $entry === '..') {
                continue;
            }
            $fullPath = rtrim($path, '/\\') . DIRECTORY_SEPARATOR . $entry;
            if (is_file($fullPath)) {
                $files[] = $fullPath;
            }
        }

        sort($files);
        return $files;
    }
}