<?php

namespace Modules\EcommerceFinance\Services;

use Illuminate\Http\Client\ConnectionException;
use Illuminate\Http\Client\RequestException;
use Illuminate\Support\Facades\Http;
use Modules\EcommerceFinance\Exceptions\DingTalkProcessInstanceException;

class DingTalkProcessInstanceClient
{
    private const PROCESS_INSTANCE_URL = 'https://api.dingtalk.com/v1.0/workflow/processInstances';

    private const TOKEN_SAFETY_SECONDS = 60;

    private ?string $accessToken = null;

    private int $accessTokenExpiresAt = 0;

    /** @var array<string,array<string,mixed>> */
    private array $snapshots = [];

    public function isConfigured(): bool
    {
        return trim((string) config('dingtalk.client_id', '')) !== ''
            && trim((string) config('dingtalk.client_secret', '')) !== '';
    }

    /**
     * Return DingTalk's latest form component values by component name.
     *
     * @return array<string,mixed>
     */
    public function formValues(string $processInstanceId): array
    {
        return $this->processSnapshot($processInstanceId)['form_values'];
    }

    /**
     * @return array{
     *     form_values:array<string,mixed>,
     *     tasks:list<array<string,mixed>>,
     *     operation_records:list<array<string,mixed>>,
     *     status:?string,
     *     result:?string
     * }
     */
    public function processSnapshot(string $processInstanceId): array
    {
        $processInstanceId = trim($processInstanceId);
        if ($processInstanceId === '') {
            throw new DingTalkProcessInstanceException(
                'DingTalk process instance ID is required.',
            );
        }
        if (isset($this->snapshots[$processInstanceId])) {
            return $this->snapshots[$processInstanceId];
        }

        try {
            $response = Http::acceptJson()
                ->timeout($this->timeout())
                ->withHeaders([
                    'x-acs-dingtalk-access-token' => $this->appAccessToken(),
                ])
                ->get(self::PROCESS_INSTANCE_URL, [
                    'processInstanceId' => $processInstanceId,
                ]);
        } catch (ConnectionException|RequestException $exception) {
            throw new DingTalkProcessInstanceException(
                'DingTalk process instance lookup failed.',
                true,
                $exception,
            );
        }

        if (! $response->successful()) {
            $status = $response->status();

            throw new DingTalkProcessInstanceException(
                'DingTalk process instance lookup returned HTTP ' . $status . '.',
                in_array($status, [401, 403, 429], true) || $status >= 500,
            );
        }

        $result = $response->json('result');
        if (! is_array($result)) {
            throw new DingTalkProcessInstanceException(
                'DingTalk process instance response was incomplete.',
            );
        }

        $values = [];
        foreach ((array) ($result['formComponentValues'] ?? []) as $component) {
            if (! is_array($component)) {
                continue;
            }
            $name = trim((string) ($component['name'] ?? ''));
            if ($name !== '') {
                $values[$name] = $component['value'] ?? null;
            }
        }

        return $this->snapshots[$processInstanceId] = [
            'form_values' => $values,
            'tasks' => array_values(array_filter(
                (array) ($result['tasks'] ?? []),
                'is_array',
            )),
            'operation_records' => array_values(array_filter(
                (array) ($result['operationRecords'] ?? []),
                'is_array',
            )),
            'status' => isset($result['status']) ? (string) $result['status'] : null,
            'result' => isset($result['result']) ? (string) $result['result'] : null,
        ];
    }

    private function appAccessToken(): string
    {
        if ($this->accessToken !== null && time() < $this->accessTokenExpiresAt) {
            return $this->accessToken;
        }
        if (! $this->isConfigured()) {
            throw new DingTalkProcessInstanceException(
                'DingTalk process API credentials are not configured.',
                true,
            );
        }

        try {
            $response = Http::acceptJson()
                ->timeout($this->timeout())
                ->get((string) config('dingtalk.app_token_url'), [
                    'appkey' => (string) config('dingtalk.client_id'),
                    'appsecret' => (string) config('dingtalk.client_secret'),
                ])
                ->throw();
        } catch (RequestException $exception) {
            throw new DingTalkProcessInstanceException(
                'DingTalk application token lookup failed.',
                true,
                $exception,
            );
        }

        $token = trim((string) $response->json('access_token'));
        if ((int) $response->json('errcode', -1) !== 0 || $token === '') {
            throw new DingTalkProcessInstanceException(
                'DingTalk application token was unavailable.',
                true,
            );
        }

        $expiresIn = max(300, (int) $response->json('expires_in', 7200));
        $this->accessToken = $token;
        $this->accessTokenExpiresAt = time() + max(
            120,
            $expiresIn - self::TOKEN_SAFETY_SECONDS,
        );

        return $token;
    }

    private function timeout(): int
    {
        return max(3, min(30, (int) config('dingtalk.timeout', 10)));
    }
}