<?php

declare(strict_types=1);

namespace App\Http\Controllers\Api\Admin;

use App\Constants\ErrorCode;
use App\Http\Controllers\Controller;
use App\Models\Admin;
use App\Models\LlmProvider;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Log;
use Illuminate\Validation\ValidationException;

class LlmProviderController extends Controller
{
    /**
     * @var Admin
     */
    private readonly Admin $admin;

    public function __construct(Request $request)
    {
        $admin = $request->admin;
        if (!$admin instanceof Admin) {
            throw new \RuntimeException('管理員信息未找到。');
        }
        $this->admin = $admin;
    }

    /**
     * 獲取 LLM 提供商列表
     *
     * @return JsonResponse
     */
    public function index(): JsonResponse
    {
        try {
            /** @var \Illuminate\Database\Eloquent\Builder $providers */
            $providers = LlmProvider::select([
                'id',
                'name',
                'service_name',
                'api_url',
                'status',
                'created_at',
            ]);

            // 如果不是超級管理員，只能看到自己管理的提供商
            if (!$this->admin->isSuperAdmin()) {
                $providers->whereHas('clients', function ($query) {
                    $query->whereHas('admins', function ($query) {
                        $query->where('admin_id', $this->admin->id);
                    });
                });
            }

            /** @var \Illuminate\Database\Eloquent\Collection $providerList */
            $providerList = $providers->get();

            return response()->json([
                'items' => $providerList->map(fn($provider) => [
                    'id' => $provider->id,
                    'name' => $provider->name,
                    'service_name' => $provider->service_name,
                    'api_url' => $provider->api_url,
                    'status' => $provider->status,
                    'created_at' => $provider->created_at->toIso8601String(),
                ])
            ]);

        } catch (\Exception $e) {
            Log::error('Error fetching LLM providers', [
                'error' => $e->getMessage(),
                'trace' => $e->getTraceAsString(),
            ]);

            return response()->json([
                'error' => ErrorCode::SERVER_ERROR,
                'message' => ErrorCode::getMessage(ErrorCode::SERVER_ERROR)
            ]);
        }
    }

    /**
     * 新增 LLM 提供商
     *
     * @param Request $request
     * @return JsonResponse
     * @throws ValidationException
     */
    public function store(Request $request): JsonResponse
    {
        try {
            // 只有超級管理員可以新增提供商
            if (!$this->admin->isSuperAdmin()) {
                return response()->json([
                    'error' => ErrorCode::FORBIDDEN,
                    'message' => '只有超級管理員可以新增 LLM 提供商。'
                ]);
            }

            /** @var array{
             *     name: string,
             *     service_name: string,
             *     api_url: string,
             *     api_token: string
             * } $validated */
            $validated = $request->validate([
                'name' => [
                    'required',
                    'string',
                    'max:100',
                    'unique:llm_providers',
                ],
                'service_name' => [
                    'required',
                    'string',
                    'max:100',
                ],
                'api_url' => [
                    'required',
                    'string',
                    'url',
                    'max:255',
                ],
                'api_token' => [
                    'required',
                    'string',
                    'max:255',
                ],
            ]);

            $validated['status'] = LlmProvider::STATUS_ACTIVE;

            /** @var LlmProvider $provider */
            $provider = LlmProvider::create($validated);

            return response()->json([
                'id' => $provider->id,
                'name' => $provider->name,
                'service_name' => $provider->service_name,
                'api_url' => $provider->api_url,
                'api_token' => $provider->api_token,
                'created_at' => $provider->created_at->toIso8601String(),
            ]);

        } catch (ValidationException $e) {
            return response()->json([
                'error' => ErrorCode::VALIDATION_ERROR,
                'message' => ErrorCode::getMessage(ErrorCode::VALIDATION_ERROR),
                'errors' => $e->errors()
            ]);
        } catch (\Exception $e) {
            Log::error('Error creating LLM provider', [
                'error' => $e->getMessage(),
                'trace' => $e->getTraceAsString(),
                'request_data' => $request->except(['api_token']),
            ]);

            return response()->json([
                'error' => ErrorCode::SERVER_ERROR,
                'message' => ErrorCode::getMessage(ErrorCode::SERVER_ERROR)
            ]);
        }
    }

    /**
     * 修改 LLM 提供商
     */
    public function update(Request $request, int $id): JsonResponse
    {
        try {
            $provider = LlmProvider::findOrFail($id);

            if (!$this->admin->canManageLlmProvider($provider->id)) {
                return response()->json([
                    'error' => ErrorCode::FORBIDDEN,
                    'message' => '您無權管理該 LLM 提供商。'
                ]);
            }

            $validated = $request->validate([
                'name' => [
                    'required',
                    'string',
                    'max:100',
                    "unique:llm_providers,name,{$id}",
                ],
                'service_name' => [
                    'required',
                    'string',
                    'max:100',
                ],
                'api_url' => [
                    'required',
                    'string',
                    'url',
                    'max:255',
                ],
                'api_token' => [
                    'required',
                    'string',
                    'max:255',
                ],
                'status' => [
                    'required',
                    'string',
                    'in:active,inactive',
                ],
            ]);

            // 如果要停用提供商，檢查是否有客戶在使用
            if ($validated['status'] === LlmProvider::STATUS_INACTIVE &&
                $provider->status === LlmProvider::STATUS_ACTIVE) {
                if ($provider->clients()->exists()) {
                    return response()->json([
                        'error' => ErrorCode::RESOURCE_IN_USE,
                        'message' => '該提供商正在被客戶使用，無法停用。'
                    ]);
                }
            }

            $provider->update($validated);

            return response()->json([
                'id' => $provider->id,
                'name' => $provider->name,
                'service_name' => $provider->service_name,
                'api_url' => $provider->api_url,
                'api_token' => $provider->api_token,
                'updated_at' => $provider->updated_at->toIso8601String(),
            ]);

        } catch (ValidationException $e) {
            return response()->json([
                'error' => ErrorCode::VALIDATION_ERROR,
                'message' => ErrorCode::getMessage(ErrorCode::VALIDATION_ERROR),
                'errors' => $e->errors()
            ]);
        } catch (\Exception $e) {
            Log::error('Error updating LLM provider', [
                'error' => $e->getMessage(),
                'trace' => $e->getTraceAsString(),
                'provider_id' => $id,
                'request_data' => $request->except(['api_token']),
            ]);

            return response()->json([
                'error' => ErrorCode::SERVER_ERROR,
                'message' => ErrorCode::getMessage(ErrorCode::SERVER_ERROR)
            ]);
        }
    }

    /**
     * 刪除 LLM 提供商
     */
    public function destroy(int $id): JsonResponse
    {
        try {
            $provider = LlmProvider::findOrFail($id);

            if (!$this->admin->canManageLlmProvider($provider->id)) {
                return response()->json([
                    'error' => ErrorCode::FORBIDDEN,
                    'message' => '您無權管理該 LLM 提供商。'
                ]);
            }

            // 檢查是否有客戶在使用
            if ($provider->clients()->exists()) {
                return response()->json([
                    'error' => ErrorCode::RESOURCE_IN_USE,
                    'message' => '該提供商正在被客戶使用，無法刪除。'
                ]);
            }

            $providerName = $provider->name;
            $provider->delete();

            return response()->json([
                'message' => 'LLM 提供商已刪除。'
            ]);

        } catch (\Exception $e) {
            Log::error('Error deleting LLM provider', [
                'error' => $e->getMessage(),
                'trace' => $e->getTraceAsString(),
                'provider_id' => $id,
            ]);

            return response()->json([
                'error' => ErrorCode::SERVER_ERROR,
                'message' => ErrorCode::getMessage(ErrorCode::SERVER_ERROR)
            ]);
        }
    }
}