<?php

namespace App\Libraries\DigitMotor;

use App\Models\MotorTokenModel;
use Config\DigitMotor as DigitMotorConfig;

/**
 * Owns Digit OneAPI token lifecycle (cache + refresh).
 */
class DigitAuthClient
{
    protected DigitMotorConfig $config;
    protected MotorTokenModel $tokenModel;

    public function __construct(?DigitMotorConfig $config = null)
    {
        $this->config     = $config ?? config('DigitMotor');
        $this->tokenModel = new MotorTokenModel();
        helper('api');
    }

    /**
     * Return a valid Bearer access token, refreshing from Digit when needed.
     *
     * @throws DigitApiException
     */
    public function getToken(bool $forceRefresh = false): string
    {
        if (!$forceRefresh) {
            $cached = $this->tokenModel->getByEnvironment($this->config->environment);
            if ($cached && !empty($cached['access_token']) && !empty($cached['expires_at'])) {
                $expiresAt = strtotime($cached['expires_at']);
                if ($expiresAt !== false && ($expiresAt - $this->config->tokenLeewaySec) > time()) {
                    return $cached['access_token'];
                }
            }
        }

        return $this->fetchAndStoreToken();
    }

    /**
     * Force refresh (e.g. after 401).
     *
     * @throws DigitApiException
     */
    public function refreshToken(): string
    {
        return $this->getToken(true);
    }

    /**
     * @throws DigitApiException
     */
    protected function fetchAndStoreToken(): string
    {
        if ($this->config->username === '' || $this->config->password === '') {
            throw new DigitApiException(
                'Digit Motor credentials are not configured. Set DIGIT_MOTOR_USERNAME and DIGIT_MOTOR_PASSWORD in .env.',
                'CONFIG',
                0
            );
        }

        $url = $this->config->baseUrl . $this->config->authPath;
        $headers = ['Content-Type: application/json'];
        $body = [
            'username' => $this->config->username,
            'password' => $this->config->password,
        ];

        $response = call_third_party_api($url, 'POST', $headers, $body);
        $httpCode = (int) ($response['code'] ?? 0);
        $data     = $response['data'] ?? [];

        if (is_string($data)) {
            $decoded = json_decode($data, true);
            $data = is_array($decoded) ? $decoded : [];
        }

        $accessToken = $data['access_token']
            ?? $data['accessToken']
            ?? $data['token']
            ?? null;

        if (empty($accessToken) || empty($response['status'])) {
            $msg = $data['message'] ?? $data['error'] ?? 'Digit token generation failed.';
            throw new DigitApiException(
                is_string($msg) ? $msg : 'Digit token generation failed.',
                $data['code'] ?? (string) $httpCode,
                $httpCode,
                $data
            );
        }

        $expiresIn    = (int) ($data['expires_in'] ?? $data['expiresIn'] ?? 900);
        $refreshToken = $data['refresh_token'] ?? $data['refreshToken'] ?? null;
        $expiresAt    = date('Y-m-d H:i:s', time() + max(60, $expiresIn));

        $this->tokenModel->upsertToken(
            $this->config->environment,
            $accessToken,
            $refreshToken,
            $expiresAt
        );

        return $accessToken;
    }
}