<?php
/**
 * CODING CONVENTION:
 * This file follows the coding convention where variable_names and function_names
 * use snake_case (underscore_wherever_possible).
 */

namespace App\RSpade\Core\Task;

use Exception;
use Illuminate\Support\Facades\DB;
use App\RSpade\Core\Manifest\Manifest;
use App\RSpade\Core\Service\Rsx_Service_Abstract;
use App\RSpade\Core\Task\Task_Instance;
use App\RSpade\Core\Task\Task_Status;

/**
 * Task - Unified task execution system
 *
 * Handles background task execution:
 * - Internal PHP task calls (internal method)
 * - Future: Queue integration, scheduling, progress tracking
 */
class Task
{
    /**
     * Execute a task internally from PHP code
     *
     * Used for server-side code to invoke tasks without CLI overhead.
     * This is useful for calling tasks from other tasks, background jobs, etc.
     *
     * @param string $rsx_service Service name (e.g., 'Seeder_Service')
     * @param string $rsx_task Task/method name (e.g., 'seed_clients')
     * @param array $params Parameters to pass to the task
     * @return mixed The response from the task method
     * @throws Exception
     */
    public static function internal($rsx_service, $rsx_task, $params = [])
    {
        // Get manifest to find service
        $manifest = Manifest::get_all();
        $service_class = null;
        $file_info = null;

        // Search for service class in manifest
        foreach ($manifest as $file_path => $info) {
            // Skip non-PHP files or files without classes
            if (!isset($info['class']) || !isset($info['fqcn'])) {
                continue;
            }

            // Check if class name matches exactly (without namespace)
            $class_basename = basename(str_replace('\\', '/', $info['fqcn']));

            if ($class_basename === $rsx_service) {
                $service_class = $info['fqcn'];
                $file_info = $info;
                break;
            }
        }

        if (!$service_class) {
            throw new Exception("Service class not found: {$rsx_service}");
        }

        // Check if class exists
        if (!class_exists($service_class)) {
            throw new Exception("Service class does not exist: {$service_class}");
        }

        // Check if it's a subclass of Rsx_Service_Abstract
        if (!Manifest::php_is_subclass_of($service_class, Rsx_Service_Abstract::class)) {
            throw new Exception("Service {$service_class} must extend Rsx_Service_Abstract");
        }

        // Check if method exists and has Task attribute
        if (!isset($file_info['public_static_methods'][$rsx_task])) {
            throw new Exception("Task {$rsx_task} not found in service {$service_class}");
        }

        $method_info = $file_info['public_static_methods'][$rsx_task];
        $has_task = false;

        // Check for Task attribute in method metadata
        if (isset($method_info['attributes'])) {
            foreach ($method_info['attributes'] as $attr_name => $attr_instances) {
                if ($attr_name === 'Task' || str_ends_with($attr_name, '\\Task')) {
                    $has_task = true;
                    break;
                }
            }
        }

        if (!$has_task) {
            throw new Exception("Method {$rsx_task} in service {$service_class} must have #[Task] attribute");
        }

        // Create task instance for immediate execution
        $task_instance = new Task_Instance(
            $service_class,
            $rsx_task,
            $params,
            'default',
            true  // immediate execution
        );

        // Mark as started
        $task_instance->mark_started();

        try {
            // Call pre_task() if exists
            if (method_exists($service_class, 'pre_task')) {
                $pre_result = $service_class::pre_task($task_instance, $params);
                if ($pre_result !== null) {
                    // pre_task returned something, use that as response
                    $task_instance->mark_completed($pre_result);
                    return $pre_result;
                }
            }

            // Call the actual task method
            $response = $service_class::$rsx_task($task_instance, $params);

            // Mark as completed
            $task_instance->mark_completed($response);

            // Filter response through JSON encode/decode to remove PHP objects
            // (similar to Ajax behavior)
            $filtered_response = json_decode(json_encode($response), true);

            return $filtered_response;
        } catch (Exception $e) {
            // Mark as failed
            $task_instance->mark_failed($e->getMessage());
            throw $e;
        }
    }

    /**
     * Format task response for CLI output
     * Wraps the response in a consistent format
     *
     * @param mixed $response Task return value
     * @return array Formatted response
     */
    public static function format_task_response($response): array
    {
        return [
            'success' => true,
            'result' => $response,
        ];
    }

    /**
     * Dispatch a task to the queue for async execution
     *
     * Creates a database record for the task and returns the task ID.
     * Task will be picked up and executed by the task processor (rsx:task:process).
     *
     * @param string $rsx_service Service name (e.g., 'Seeder_Service')
     * @param string $rsx_task Task/method name (e.g., 'seed_clients')
     * @param array $params Parameters to pass to the task
     * @param array $options Optional task options:
     *   - 'queue' => Queue name (default: 'default')
     *   - 'scheduled_for' => Timestamp when task should run (default: now)
     *   - 'timeout' => Maximum execution time in seconds (default: from config)
     * @return int Task ID
     * @throws Exception
     */
    public static function dispatch(string $rsx_service, string $rsx_task, array $params = [], array $options = []): int
    {
        // Get manifest to find service
        $manifest = Manifest::get_all();
        $service_class = null;
        $file_info = null;

        // Search for service class in manifest
        foreach ($manifest as $file_path => $info) {
            // Skip non-PHP files or files without classes
            if (!isset($info['class']) || !isset($info['fqcn'])) {
                continue;
            }

            // Check if class name matches exactly (without namespace)
            $class_basename = basename(str_replace('\\', '/', $info['fqcn']));

            if ($class_basename === $rsx_service) {
                $service_class = $info['fqcn'];
                $file_info = $info;
                break;
            }
        }

        if (!$service_class) {
            throw new Exception("Service class not found: {$rsx_service}");
        }

        // Check if class exists
        if (!class_exists($service_class)) {
            throw new Exception("Service class does not exist: {$service_class}");
        }

        // Check if it's a subclass of Rsx_Service_Abstract
        if (!Manifest::php_is_subclass_of($service_class, Rsx_Service_Abstract::class)) {
            throw new Exception("Service {$service_class} must extend Rsx_Service_Abstract");
        }

        // Check if method exists and has Task attribute
        if (!isset($file_info['public_static_methods'][$rsx_task])) {
            throw new Exception("Task {$rsx_task} not found in service {$service_class}");
        }

        $method_info = $file_info['public_static_methods'][$rsx_task];
        $has_task = false;

        // Check for Task attribute in method metadata
        if (isset($method_info['attributes'])) {
            foreach ($method_info['attributes'] as $attr_name => $attr_instances) {
                if ($attr_name === 'Task' || str_ends_with($attr_name, '\\Task')) {
                    $has_task = true;
                    break;
                }
            }
        }

        if (!$has_task) {
            throw new Exception("Method {$rsx_task} in service {$service_class} must have #[Task] attribute");
        }

        // Create task instance
        $instance = new Task_Instance(
            $service_class,
            $rsx_task,
            $params,
            $options['queue'] ?? 'default',
            false  // not immediate
        );

        // Create database record
        $data = [
            'class' => $service_class,
            'method' => $rsx_task,
            'queue' => $options['queue'] ?? 'default',
            'status' => Task_Status::PENDING,
            'params' => json_encode($params),
            'scheduled_for' => $options['scheduled_for'] ?? now(),
            'timeout' => $options['timeout'] ?? config('rsx.tasks.default_timeout'),
            'created_at' => now(),
            'updated_at' => now(),
        ];

        $task_id = DB::table('_task_queue')->insertGetId($data);

        return $task_id;
    }

    /**
     * Get the status of a task
     *
     * Returns task information including status, logs, result, and error.
     *
     * @param int $task_id Task ID
     * @return array|null Task status data or null if not found
     */
    public static function status(int $task_id): ?array
    {
        $row = DB::table('_task_queue')->where('id', $task_id)->first();

        if (!$row) {
            return null;
        }

        return [
            'id' => $row->id,
            'class' => $row->class,
            'method' => $row->method,
            'queue' => $row->queue,
            'status' => $row->status,
            'params' => json_decode($row->params, true),
            'result' => json_decode($row->result, true),
            'logs' => $row->logs ? explode("\n", $row->logs) : [],
            'error' => $row->error,
            'scheduled_for' => $row->scheduled_for,
            'started_at' => $row->started_at,
            'completed_at' => $row->completed_at,
            'created_at' => $row->created_at,
            'updated_at' => $row->updated_at,
        ];
    }

    /**
     * Get all scheduled tasks from manifest
     *
     * Scans the manifest for methods with #[Schedule] attribute
     * and returns information about each scheduled task.
     *
     * @return array Array of scheduled task definitions
     */
    public static function get_scheduled_tasks(): array
    {
        $manifest = Manifest::get_all();
        $scheduled_tasks = [];

        foreach ($manifest as $file_path => $info) {
            // Skip non-PHP files or files without classes
            if (!isset($info['class']) || !isset($info['fqcn'])) {
                continue;
            }

            // Check if it's a service class
            if (!isset($info['public_static_methods'])) {
                continue;
            }

            foreach ($info['public_static_methods'] as $method_name => $method_info) {
                // Check for Schedule attribute
                if (!isset($method_info['attributes'])) {
                    continue;
                }

                foreach ($method_info['attributes'] as $attr_name => $attr_instances) {
                    if ($attr_name === 'Schedule' || str_ends_with($attr_name, '\\Schedule')) {
                        // Found a scheduled task
                        foreach ($attr_instances as $attr_instance) {
                            $cron_expression = $attr_instance[0] ?? null;
                            $queue = $attr_instance[1] ?? 'scheduled';

                            if ($cron_expression) {
                                $scheduled_tasks[] = [
                                    'class' => $info['fqcn'],
                                    'method' => $method_name,
                                    'cron_expression' => $cron_expression,
                                    'queue' => $queue,
                                ];
                            }
                        }
                    }
                }
            }
        }

        return $scheduled_tasks;
    }
}