<?php

namespace App\Http\Controllers;

use App\Models\UsageLog;
use App\Models\GatewayUser;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;

class UsageLogController extends Controller
{
    /**
     * Display a listing of usage logs with filters
     */
    public function index(Request $request)
    {
        $query = UsageLog::with(['gatewayUser', 'apiKey']);

        // Date Range Filter
        if ($request->filled('date_from')) {
            $query->where('timestamp', '>=', $request->date_from . ' 00:00:00');
        }
        
        if ($request->filled('date_to')) {
            $query->where('timestamp', '<=', $request->date_to . ' 23:59:59');
        }

        // User Filter
        if ($request->filled('user_id')) {
            $query->where('user_id', $request->user_id);
        }

        // Provider Filter
        if ($request->filled('provider')) {
            $query->where('provider', $request->provider);
        }

        // Model Filter
        if ($request->filled('model')) {
            $query->where('model', $request->model);
        }

        // Status Filter
        if ($request->filled('status')) {
            if ($request->status === 'success') {
                $query->success();
            } elseif ($request->status === 'failed') {
                $query->failed();
            }
        }

        // Get filter options for dropdowns
        $users = GatewayUser::select('user_id', 'alias')
            ->orderBy('alias')
            ->get();
        
        $providers = UsageLog::select('provider')
            ->distinct()
            ->whereNotNull('provider')
            ->orderBy('provider')
            ->pluck('provider');
        
        $models = UsageLog::select('model')
            ->distinct()
            ->whereNotNull('model')
            ->orderBy('model')
            ->pluck('model');

        // Get summary statistics for current filter
        $summary = $query->clone()
            ->selectRaw('
                COUNT(*) as total_requests,
                SUM(CASE WHEN status = \'success\' THEN 1 ELSE 0 END) as successful_requests,
                SUM(prompt_tokens) as total_prompt_tokens,
                SUM(completion_tokens) as total_completion_tokens,
                SUM(total_tokens) as total_tokens,
                SUM(cost) as total_cost
            ')
            ->first();

        // Paginate results
        $logs = $query->orderByDesc('timestamp')
            ->paginate(50)
            ->withQueryString(); // Preserve query parameters

        return view('usage-logs.index', compact(
            'logs',
            'users',
            'providers',
            'models',
            'summary'
        ));
    }

    /**
     * Export usage logs to CSV
     */
    public function export(Request $request)
    {
        $query = UsageLog::with(['gatewayUser', 'apiKey']);

        // Apply same filters as index
        if ($request->filled('date_from')) {
            $query->where('timestamp', '>=', $request->date_from . ' 00:00:00');
        }
        
        if ($request->filled('date_to')) {
            $query->where('timestamp', '<=', $request->date_to . ' 23:59:59');
        }

        if ($request->filled('user_id')) {
            $query->where('user_id', $request->user_id);
        }

        if ($request->filled('provider')) {
            $query->where('provider', $request->provider);
        }

        if ($request->filled('model')) {
            $query->where('model', $request->model);
        }

        if ($request->filled('status')) {
            if ($request->status === 'success') {
                $query->success();
            } elseif ($request->status === 'failed') {
                $query->failed();
            }
        }

        // Limit export to 10,000 records for performance
        $logs = $query->orderByDesc('timestamp')
            ->limit(10000)
            ->get();

        $filename = 'usage-logs-' . now()->format('Y-m-d-His') . '.csv';
        
        $headers = [
            'Content-Type' => 'text/csv',
            'Content-Disposition' => "attachment; filename=\"{$filename}\"",
        ];

        $callback = function() use ($logs) {
            $file = fopen('php://output', 'w');
            
            // CSV Header
            fputcsv($file, [
                'Timestamp',
                'User ID',
                'User Alias',
                'API Key',
                'Provider',
                'Model',
                'Endpoint',
                'Prompt Tokens',
                'Completion Tokens',
                'Total Tokens',
                'Cost',
                'Status',
                'Error Message'
            ]);

            // CSV Rows
            foreach ($logs as $log) {
                fputcsv($file, [
                    $log->timestamp->format('Y-m-d H:i:s'),
                    $log->user_id,
                    $log->gatewayUser?->alias ?? 'N/A',
                    $log->api_key_id,
                    $log->provider,
                    $log->model,
                    $log->endpoint,
                    $log->prompt_tokens,
                    $log->completion_tokens,
                    $log->total_tokens,
                    $log->cost,
                    $log->status,
                    $log->error_message ?? ''
                ]);
            }

            fclose($file);
        };

        return response()->stream($callback, 200, $headers);
    }
}