<?php
declare(strict_types=1);

namespace App\Modules\Cron;

use DateTimeImmutable;
use PDO;
use Throwable;

final class CronRepository
{
    public function __construct(private readonly PDO $pdo)
    {
    }

    public function getBoolSetting(string $key, bool $default): bool
    {
        $value = $this->getSettingValue($key);
        if ($value === null) {
            return $default;
        }

        return in_array(strtolower($value), ['1', 'true', 'yes', 'on'], true);
    }

    public function getIntSetting(string $key, int $default, int $min, int $max): int
    {
        $value = $this->getSettingValue($key);
        if ($value === null || !is_numeric($value)) {
            return max($min, min($max, $default));
        }

        return max($min, min($max, (int) $value));
    }

    public function getStringSetting(string $key, string $default): string
    {
        $value = $this->getSettingValue($key);
        if ($value === null) {
            return $default;
        }

        return $value;
    }

    public function upsertSetting(string $key, string $value): void
    {
        $statement = $this->pdo->prepare(
            'INSERT INTO app_settings (setting_key, setting_value, created_at, updated_at)
            VALUES (:setting_key, :setting_value, NOW(), NOW())
            ON DUPLICATE KEY UPDATE
                setting_value = VALUES(setting_value),
                updated_at = VALUES(updated_at)'
        );
        $statement->execute([
            'setting_key' => $key,
            'setting_value' => $value,
        ]);
    }

    /**
     * @return array<int, array<string, mixed>>
     */
    public function listSchedules(): array
    {
        $statement = $this->pdo->query(
            'SELECT id, job_type, interval_seconds, priority, max_attempts, payload, enabled, last_run_at, next_run_at
            FROM cron_schedules
            ORDER BY priority ASC, job_type ASC'
        );
        $rows = $statement->fetchAll(PDO::FETCH_ASSOC);
        if (!is_array($rows)) {
            return [];
        }

        return array_map(fn (array $row): array => $this->normalizeScheduleRow($row), $rows);
    }

    /**
     * @return array<int, array<string, mixed>>
     */
    public function listFutureJobs(int $limit = 50): array
    {
        $safeLimit = max(1, min(200, $limit));
        $statement = $this->pdo->prepare(
            'SELECT id, job_type, status, priority, attempts, max_attempts, scheduled_at, last_error, created_at
            FROM cron_jobs
            WHERE status IN ("pending", "processing")
            ORDER BY scheduled_at ASC, priority ASC, id ASC
            LIMIT :limit'
        );
        $statement->bindValue(':limit', $safeLimit, PDO::PARAM_INT);
        $statement->execute();
        $rows = $statement->fetchAll(PDO::FETCH_ASSOC);
        if (!is_array($rows)) {
            return [];
        }

        return array_map(fn (array $row): array => $this->normalizeJobRow($row), $rows);
    }

    /**
     * @return array<int, array<string, mixed>>
     */
    public function listPastJobs(int $limit = 50, int $offset = 0): array
    {
        $safeLimit = max(1, min(200, $limit));
        $safeOffset = max(0, $offset);
        $statement = $this->pdo->prepare(
            'SELECT id, job_type, status, priority, attempts, max_attempts, scheduled_at, started_at, completed_at, last_error, created_at
            FROM cron_jobs
            WHERE status IN ("completed", "failed", "cancelled")
            ORDER BY completed_at DESC, id DESC
            LIMIT :limit OFFSET :offset'
        );
        $statement->bindValue(':limit', $safeLimit, PDO::PARAM_INT);
        $statement->bindValue(':offset', $safeOffset, PDO::PARAM_INT);
        $statement->execute();
        $rows = $statement->fetchAll(PDO::FETCH_ASSOC);
        if (!is_array($rows)) {
            return [];
        }

        return array_map(fn (array $row): array => $this->normalizeJobRow($row), $rows);
    }

    public function countPastJobs(): int
    {
        $statement = $this->pdo->query(
            'SELECT COUNT(*)
            FROM cron_jobs
            WHERE status IN ("completed", "failed", "cancelled")'
        );
        $value = $statement !== false ? $statement->fetchColumn() : 0;

        return max(0, (int) $value);
    }

    /**
     * @return array<int, array<string, mixed>>
     */
    public function findDueSchedules(DateTimeImmutable $now): array
    {
        $statement = $this->pdo->prepare(
            'SELECT id, job_type, interval_seconds, priority, max_attempts, payload, enabled, last_run_at, next_run_at
            FROM cron_schedules
            WHERE enabled = 1
              AND (next_run_at IS NULL OR next_run_at <= :now)
            ORDER BY priority ASC, next_run_at ASC, id ASC'
        );
        $statement->execute([
            'now' => $now->format('Y-m-d H:i:s'),
        ]);
        $rows = $statement->fetchAll(PDO::FETCH_ASSOC);
        if (!is_array($rows)) {
            return [];
        }

        return array_map(fn (array $row): array => $this->normalizeScheduleRow($row), $rows);
    }

    /**
     * @param array<string, mixed> $schedule
     */
    public function enqueueJobFromSchedule(array $schedule, DateTimeImmutable $now): void
    {
        $payloadJson = $this->encodeJson($schedule['payload'] ?? null);

        $jobStatement = $this->pdo->prepare(
            'INSERT INTO cron_jobs (
                job_type, status, priority, payload, attempts, max_attempts,
                scheduled_at, created_at, updated_at
            ) VALUES (
                :job_type, "pending", :priority, :payload, 0, :max_attempts,
                :scheduled_at, NOW(), NOW()
            )'
        );
        $jobStatement->execute([
            'job_type' => (string) ($schedule['job_type'] ?? ''),
            'priority' => (int) ($schedule['priority'] ?? 100),
            'payload' => $payloadJson,
            'max_attempts' => max(1, (int) ($schedule['max_attempts'] ?? 3)),
            'scheduled_at' => $now->format('Y-m-d H:i:s'),
        ]);

        $intervalSeconds = max(1, (int) ($schedule['interval_seconds'] ?? 60));
        $nextRunAt = $now->modify('+' . $intervalSeconds . ' seconds');

        $scheduleStatement = $this->pdo->prepare(
            'UPDATE cron_schedules
            SET last_run_at = :last_run_at,
                next_run_at = :next_run_at,
                updated_at = NOW()
            WHERE id = :id'
        );
        $scheduleStatement->execute([
            'last_run_at' => $now->format('Y-m-d H:i:s'),
            'next_run_at' => $nextRunAt->format('Y-m-d H:i:s'),
            'id' => (int) ($schedule['id'] ?? 0),
        ]);
    }

    /**
     * @return array<string, mixed>|null
     */
    public function claimNextPendingJob(DateTimeImmutable $now): ?array
    {
        $selectStatement = $this->pdo->prepare(
            'SELECT id, job_type, status, priority, payload, attempts, max_attempts, scheduled_at
            FROM cron_jobs
            WHERE status = "pending"
              AND scheduled_at <= :now
            ORDER BY priority ASC, scheduled_at ASC, id ASC
            LIMIT 1'
        );
        $selectStatement->execute([
            'now' => $now->format('Y-m-d H:i:s'),
        ]);
        $row = $selectStatement->fetch(PDO::FETCH_ASSOC);
        if (!is_array($row)) {
            return null;
        }

        $jobId = (int) ($row['id'] ?? 0);
        if ($jobId <= 0) {
            return null;
        }

        $updateStatement = $this->pdo->prepare(
            'UPDATE cron_jobs
            SET status = "processing",
                started_at = :started_at,
                attempts = attempts + 1,
                updated_at = NOW()
            WHERE id = :id
              AND status = "pending"'
        );
        $updateStatement->execute([
            'started_at' => $now->format('Y-m-d H:i:s'),
            'id' => $jobId,
        ]);

        if ($updateStatement->rowCount() !== 1) {
            return null;
        }

        $refreshStatement = $this->pdo->prepare(
            'SELECT id, job_type, status, priority, payload, attempts, max_attempts, scheduled_at, started_at
            FROM cron_jobs
            WHERE id = :id
            LIMIT 1'
        );
        $refreshStatement->execute(['id' => $jobId]);
        $claimed = $refreshStatement->fetch(PDO::FETCH_ASSOC);
        if (!is_array($claimed)) {
            return null;
        }

        return $this->normalizeJobRow($claimed);
    }

    /**
     * @param array<string, mixed>|null $result
     */
    public function markJobCompleted(int $jobId, ?array $result = null): void
    {
        $statement = $this->pdo->prepare(
            'UPDATE cron_jobs
            SET status = "completed",
                result = :result,
                completed_at = NOW(),
                last_error = NULL,
                updated_at = NOW()
            WHERE id = :id'
        );
        $statement->execute([
            'result' => $this->encodeJson($result),
            'id' => $jobId,
        ]);
    }

    /**
     * @param array<string, mixed>|null $result
     */
    public function markJobFailed(int $jobId, string $error, DateTimeImmutable $now, int $retryDelaySeconds = 60, ?array $result = null): void
    {
        $statement = $this->pdo->prepare(
            'SELECT attempts, max_attempts
            FROM cron_jobs
            WHERE id = :id
            LIMIT 1'
        );
        $statement->execute(['id' => $jobId]);
        $row = $statement->fetch(PDO::FETCH_ASSOC);
        if (!is_array($row)) {
            return;
        }

        $attempts = (int) ($row['attempts'] ?? 0);
        $maxAttempts = max(1, (int) ($row['max_attempts'] ?? 1));
        $errorMessage = mb_substr(trim($error), 0, 500);

        if ($attempts < $maxAttempts) {
            $scheduledAt = $now->modify('+' . max(10, $retryDelaySeconds) . ' seconds');
            $retryStatement = $this->pdo->prepare(
                'UPDATE cron_jobs
                SET status = "pending",
                    result = :result,
                    scheduled_at = :scheduled_at,
                    started_at = NULL,
                    completed_at = NULL,
                    last_error = :last_error,
                    updated_at = NOW()
                WHERE id = :id'
            );
            $retryStatement->execute([
                'result' => $this->encodeJson($result),
                'scheduled_at' => $scheduledAt->format('Y-m-d H:i:s'),
                'last_error' => $errorMessage,
                'id' => $jobId,
            ]);
            return;
        }

        $failStatement = $this->pdo->prepare(
            'UPDATE cron_jobs
            SET status = "failed",
                result = :result,
                completed_at = NOW(),
                last_error = :last_error,
                updated_at = NOW()
            WHERE id = :id'
        );
        $failStatement->execute([
            'result' => $this->encodeJson($result),
            'last_error' => $errorMessage,
            'id' => $jobId,
        ]);
    }

    public function upsertSchedule(
        string $jobType,
        int $intervalSeconds,
        int $priority,
        int $maxAttempts,
        ?array $payload,
        bool $enabled
    ): void {
        $statement = $this->pdo->prepare(
            'INSERT INTO cron_schedules (
                job_type, interval_seconds, priority, max_attempts, payload, enabled, last_run_at, next_run_at, created_at, updated_at
            ) VALUES (
                :job_type, :interval_seconds, :priority, :max_attempts, :payload, :enabled, NULL, NOW(), NOW(), NOW()
            )
            ON DUPLICATE KEY UPDATE
                interval_seconds = VALUES(interval_seconds),
                priority = VALUES(priority),
                max_attempts = VALUES(max_attempts),
                payload = VALUES(payload),
                enabled = VALUES(enabled),
                updated_at = VALUES(updated_at)'
        );
        $statement->execute([
            'job_type' => trim($jobType),
            'interval_seconds' => max(1, $intervalSeconds),
            'priority' => max(1, min(255, $priority)),
            'max_attempts' => max(1, min(20, $maxAttempts)),
            'payload' => $this->encodeJson($payload),
            'enabled' => $enabled ? 1 : 0,
        ]);
    }

    public function updateScheduleInterval(string $jobType, int $intervalSeconds): void
    {
        $statement = $this->pdo->prepare(
            'UPDATE cron_schedules
            SET interval_seconds = :interval_seconds,
                updated_at = NOW()
            WHERE job_type = :job_type'
        );
        $statement->execute([
            'interval_seconds' => max(1, $intervalSeconds),
            'job_type' => trim($jobType),
        ]);
    }

    public function getScheduleInterval(string $jobType): ?int
    {
        $statement = $this->pdo->prepare(
            'SELECT interval_seconds FROM cron_schedules WHERE job_type = :job_type LIMIT 1'
        );
        $statement->execute(['job_type' => trim($jobType)]);
        $value = $statement->fetchColumn();

        return $value !== false ? (int) $value : null;
    }

    private function getSettingValue(string $key): ?string
    {
        try {
            $statement = $this->pdo->prepare(
                'SELECT setting_value
                FROM app_settings
                WHERE setting_key = :setting_key
                LIMIT 1'
            );
            $statement->execute(['setting_key' => $key]);
            $value = $statement->fetchColumn();
        } catch (Throwable) {
            return null;
        }

        if (!is_string($value)) {
            return null;
        }

        return trim($value);
    }

    /**
     * @param array<string, mixed> $row
     * @return array<string, mixed>
     */
    private function normalizeScheduleRow(array $row): array
    {
        return [
            'id' => (int) ($row['id'] ?? 0),
            'job_type' => (string) ($row['job_type'] ?? ''),
            'interval_seconds' => (int) ($row['interval_seconds'] ?? 0),
            'priority' => (int) ($row['priority'] ?? 100),
            'max_attempts' => (int) ($row['max_attempts'] ?? 3),
            'payload' => $this->decodeJson((string) ($row['payload'] ?? '')),
            'enabled' => (int) ($row['enabled'] ?? 0) === 1,
            'last_run_at' => (string) ($row['last_run_at'] ?? ''),
            'next_run_at' => (string) ($row['next_run_at'] ?? ''),
        ];
    }

    /**
     * @param array<string, mixed> $row
     * @return array<string, mixed>
     */
    private function normalizeJobRow(array $row): array
    {
        return [
            'id' => (int) ($row['id'] ?? 0),
            'job_type' => (string) ($row['job_type'] ?? ''),
            'status' => (string) ($row['status'] ?? ''),
            'priority' => (int) ($row['priority'] ?? 100),
            'payload' => $this->decodeJson((string) ($row['payload'] ?? '')),
            'result' => $this->decodeJson((string) ($row['result'] ?? '')),
            'attempts' => (int) ($row['attempts'] ?? 0),
            'max_attempts' => (int) ($row['max_attempts'] ?? 3),
            'scheduled_at' => (string) ($row['scheduled_at'] ?? ''),
            'started_at' => (string) ($row['started_at'] ?? ''),
            'completed_at' => (string) ($row['completed_at'] ?? ''),
            'last_error' => (string) ($row['last_error'] ?? ''),
            'created_at' => (string) ($row['created_at'] ?? ''),
        ];
    }

    private function encodeJson(mixed $value): ?string
    {
        if ($value === null) {
            return null;
        }
        if (!is_array($value)) {
            return null;
        }
        if ($value === []) {
            return null;
        }

        return json_encode($value, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES) ?: null;
    }

    private function decodeJson(string $value): ?array
    {
        $trimmed = trim($value);
        if ($trimmed === '') {
            return null;
        }

        $decoded = json_decode($trimmed, true);
        return is_array($decoded) ? $decoded : null;
    }
}