<?php

namespace App\Helpers;

use App\Models\CDMasterModel;
use App\Models\ClientDepositModel;
use App\Models\ClientRMModel;

class CdLowBalanceAlertHelper
{
    /**
     * Check one CD account after a balance reduction and notify account managers if below threshold.
     */
    public static function triggerAfterBalanceReduction(?int $cdAcPk, float $currentBalance): void
    {
        if ($cdAcPk === null || $cdAcPk <= 0) {
            return;
        }

        $account = self::buildLowBalanceAccount($cdAcPk, $currentBalance);
        if ($account === null) {
            return;
        }

        $result = self::sendAccountManagerAlert($account);
        log_message('error', 'CdLowBalanceAlertHelper triggerAfterBalanceReduction cd_ac_pk=' . $cdAcPk . ': ' . json_encode($result));
    }

    /**
     * Cron entry: scan all CD masters with alert threshold configured.
     *
     * @return array<string, mixed>
     */
    public static function runCron(): array
    {
        log_message('error', 'cronCdLowBalanceAlert: started');

        try {
            $cdMasterModel = new CDMasterModel();
            $cdMasters = $cdMasterModel->getCdMastersWithLowAlertThreshold();
            log_message('error', 'cronCdLowBalanceAlert: CD masters with alert threshold count = ' . count($cdMasters));

            $depositModel = new ClientDepositModel();
            $lowBalanceAccounts = [];

            foreach ($cdMasters as $cdMaster) {
                $cdAcPk = (int) ($cdMaster['id'] ?? 0);
                $threshold = (float) ($cdMaster['cd_balance_low_alert_amount'] ?? 0);

                if ($cdAcPk <= 0 || $threshold <= 0) {
                    continue;
                }

                $currentBalance = self::resolveCurrentBalance($depositModel, $cdAcPk, (float) ($cdMaster['opening_bal'] ?? 0));
                if ($currentBalance >= $threshold) {
                    continue;
                }

                $lowBalanceAccounts[] = array_merge($cdMaster, [
                    'current_balance' => $currentBalance,
                    'alert_amount' => $threshold,
                ]);
            }

            if (empty($lowBalanceAccounts)) {
                $response = [
                    'status' => true,
                    'message' => 'No CD accounts below the configured low-balance alert amount.',
                    'low_balance_count' => 0,
                    'account_manager_mails_sent' => 0,
                    'data' => [],
                    'errors' => [],
                ];
                log_message('error', 'cronCdLowBalanceAlert: ' . json_encode($response));

                return $response;
            }

            $accountManagerMailsSent = 0;
            $mailErrors = [];
            $data = [];

            foreach ($lowBalanceAccounts as $account) {
                $result = self::sendAccountManagerAlert($account);
                $accountManagerMailsSent += (int) ($result['sent'] ?? 0);
                if (! empty($result['errors'])) {
                    $mailErrors = array_merge($mailErrors, $result['errors']);
                }
                if (! empty($result['data'])) {
                    $data = array_merge($data, $result['data']);
                }
            }

            $response = [
                'status' => true,
                'message' => 'CD low balance alert cron completed.',
                'low_balance_count' => count($lowBalanceAccounts),
                'account_manager_mails_sent' => $accountManagerMailsSent,
                'data' => $data,
                'errors' => $mailErrors,
            ];
            log_message('error', 'cronCdLowBalanceAlert: ' . json_encode($response));

            return $response;
        } catch (\Throwable $e) {
            $response = [
                'status' => false,
                'message' => 'CD low balance alert cron failed.',
                'low_balance_count' => 0,
                'account_manager_mails_sent' => 0,
                'data' => [],
                'errors' => [$e->getMessage()],
            ];
            log_message('error', 'cronCdLowBalanceAlert Exception: ' . $e->getMessage());
            log_message('error', 'cronCdLowBalanceAlert: ' . json_encode($response));

            return $response;
        }
    }

    /**
     * @return array<string, mixed>|null
     */
    private static function buildLowBalanceAccount(int $cdAcPk, float $currentBalance): ?array
    {
        $cdMasterModel = new CDMasterModel();
        $cdMaster = $cdMasterModel->getCdMasterWithLowAlertThresholdById($cdAcPk);
        if ($cdMaster === null) {
            return null;
        }

        $threshold = (float) ($cdMaster['cd_balance_low_alert_amount'] ?? 0);
        if ($threshold <= 0 || $currentBalance >= $threshold) {
            return null;
        }

        return array_merge($cdMaster, [
            'current_balance' => $currentBalance,
            'alert_amount' => $threshold,
        ]);
    }

    private static function resolveCurrentBalance(ClientDepositModel $depositModel, int $cdAcPk, float $openingBalance): float
    {
        $lastDeposit = $depositModel
            ->select('balance')
            ->where('cd_ac_pk', $cdAcPk)
            ->where('is_active', 1)
            ->orderBy('id', 'DESC')
            ->first();

        if (! empty($lastDeposit)) {
            return (float) ($lastDeposit['balance'] ?? 0);
        }

        return $openingBalance;
    }

    /**
     * @param array<string, mixed> $account
     * @return array{sent: int, errors: array<int, string>, data: array<int, array<string, mixed>>}
     */
    private static function sendAccountManagerAlert(array $account): array
    {
        $clientId = (int) ($account['client_id'] ?? 0);
        $cdAcPk = (int) ($account['id'] ?? 0);
        $cdAcNo = (string) ($account['cd_ac_no'] ?? '');

        if ($clientId <= 0) {
            log_message('error', 'cronCdLowBalanceAlert ACM mail: skipped, invalid client_id for cd_ac_pk=' . $cdAcPk);

            return ['sent' => 0, 'errors' => [], 'data' => []];
        }

        $recipients = self::getAccountManagerRecipients($clientId);
        if (empty($recipients)) {
            $error = "Client {$clientId}: No account manager found.";
            log_message('error', 'cronCdLowBalanceAlert ACM mail: ' . $error);

            return ['sent' => 0, 'errors' => [$error], 'data' => []];
        }

        $sent = 0;
        $errors = [];
        $data = [];
        $subject = 'CD Low Balance Alert - ' . ($account['client_name'] ?? 'Client');

        foreach ($recipients as $recipient) {
            $acmEmail = (string) ($recipient['email'] ?? '');
            $acmName = (string) ($recipient['name'] ?? 'Account Manager');
            $message = self::buildAccountManagerMailContent($account, $acmName);

            $mailResponse = MailHelper::send_email([
                'mail' => $acmEmail,
                'subject' => $subject,
                'message' => $message,
                'common' => [
                    'mail_type' => 'account_manager_cd_low_balance_alert',
                    'client_id' => $clientId,
                ],
            ]);

            $decoded = is_string($mailResponse) ? json_decode($mailResponse, true) : $mailResponse;
            $mailStatus = is_array($decoded) && ($decoded['status'] ?? '') === 'success' ? 'success' : 'failed';

            $data[] = [
                'client_id' => $clientId,
                'cd_ac_pk' => $cdAcPk,
                'cd_ac_no' => $cdAcNo,
                'acm_name' => $acmName,
                'acm_email' => $acmEmail,
                'mail_status' => $mailStatus,
            ];

            if ($mailStatus === 'success') {
                $sent++;
            } else {
                $errors[] = "Client {$clientId}: Failed to send alert to {$acmEmail}.";
            }
        }

        return ['sent' => $sent, 'errors' => $errors, 'data' => $data];
    }

    /**
     * @return array<int, array{name: string, email: string}>
     */
    private static function getAccountManagerRecipients(int $clientId): array
    {
        $rows = (new ClientRMModel())
            ->select('user_profiles.first_name, user_profiles.email')
            ->join('user_profiles', 'user_profiles.id = client_rm.user_id')
            ->where('client_rm.client_id', $clientId)
            ->where('client_rm.level', 3)
            ->where('client_rm.is_active', 1)
            ->where('user_profiles.is_active', 1)
            ->findAll();

        $recipients = [];
        $seenEmails = [];

        foreach ($rows as $row) {
            $email = strtolower(trim((string) ($row['email'] ?? '')));
            if ($email === '' || isset($seenEmails[$email])) {
                continue;
            }

            $seenEmails[$email] = true;
            $recipients[] = [
                'name' => trim((string) ($row['first_name'] ?? 'Account Manager')) ?: 'Account Manager',
                'email' => (string) $row['email'],
            ];
        }

        return $recipients;
    }

    /**
     * @param array<string, mixed> $account
     */
    private static function buildAccountManagerMailContent(array $account, string $recipientName): string
    {
        return '<p>Dear ' . esc($recipientName) . ',</p>'
            . '<p>The CD account balance for <strong>' . esc((string) ($account['client_name'] ?? '')) . '</strong> has fallen below the configured alert threshold.</p>'
            . '<table border="1" cellpadding="8" cellspacing="0" style="border-collapse:collapse;">'
            . '<tr><td><strong>Insurer</strong></td><td>' . esc((string) ($account['insurer_name'] ?? '')) . '</td></tr>'
            . '<tr><td><strong>Insurer Branch</strong></td><td>' . esc((string) ($account['insurer_branch_name'] ?? '')) . '</td></tr>'
            . '<tr><td><strong>CD Account No</strong></td><td>' . esc((string) ($account['cd_ac_no'] ?? '')) . '</td></tr>'
            . '<tr><td><strong>Current Balance</strong></td><td>' . esc(number_format((float) ($account['current_balance'] ?? 0), 2, '.', '')) . '</td></tr>'
            . '<tr><td><strong>Alert Amount</strong></td><td>' . esc(number_format((float) ($account['alert_amount'] ?? 0), 2, '.', '')) . '</td></tr>'
            . '</table>'
            . '<p>Please review the CD account and take the required action.</p>';
    }
}