<?php

namespace App\Http\Controllers;

use App\Models\Issue;
use App\Models\User;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;

class IssueReportsController extends Controller
{
    public function index(Request $request)
    {
        // Date range filter (default: last 30 days)
        $startDate = $request->date('start_date', now()->subDays(30));
        $endDate = $request->date('end_date', now());

        // Overview Statistics
        $stats = [
            'total_issues' => Issue::count(),
            'open_issues' => Issue::open()->count(),
            'closed_issues' => Issue::closed()->count(),
            'overdue_issues' => Issue::overdue()->count(),
        ];

        // Issues by Status
        $issuesByStatus = Issue::select('status', DB::raw('count(*) as count'))
            ->groupBy('status')
            ->get()
            ->mapWithKeys(fn($item) => [$item->status => $item->count]);

        // Issues by Priority
        $issuesByPriority = Issue::select('priority', DB::raw('count(*) as count'))
            ->groupBy('priority')
            ->get()
            ->mapWithKeys(fn($item) => [$item->priority => $item->count]);

        // Issues by Type
        $issuesByType = Issue::select('issue_type', DB::raw('count(*) as count'))
            ->groupBy('issue_type')
            ->get()
            ->mapWithKeys(fn($item) => [$item->issue_type => $item->count]);

        // Issues Created Over Time (last 30 days)
        $issuesCreatedOverTime = Issue::select(
                DB::raw('DATE(created_at) as date'),
                DB::raw('count(*) as count')
            )
            ->whereBetween('created_at', [$startDate, $endDate])
            ->groupBy('date')
            ->orderBy('date')
            ->get();

        // Issues Closed Over Time (last 30 days)
        $issuesClosedOverTime = Issue::select(
                DB::raw('DATE(closed_at) as date'),
                DB::raw('count(*) as count')
            )
            ->whereNotNull('closed_at')
            ->whereBetween('closed_at', [$startDate, $endDate])
            ->groupBy('date')
            ->orderBy('date')
            ->get();

        // Assignee Performance
        $assigneePerformance = User::select('users.id', 'users.name')
            ->leftJoin('issues', 'users.id', '=', 'issues.assigned_to_user_id')
            ->selectRaw('count(issues.id) as total_assigned')
            ->selectRaw('sum(case when issues.status = ? then 1 else 0 end) as completed', [Issue::STATUS_CLOSED])
            ->selectRaw('sum(case when issues.due_date < NOW() and issues.status != ? then 1 else 0 end) as overdue', [Issue::STATUS_CLOSED])
            ->groupBy('users.id', 'users.name')
            ->having('total_assigned', '>', 0)
            ->orderByDesc('total_assigned')
            ->limit(10)
            ->get()
            ->map(function ($user) {
                $user->completion_rate = $user->total_assigned > 0
                    ? round(($user->completed / $user->total_assigned) * 100, 1)
                    : 0;
                return $user;
            });

        // Time Tracking Metrics
        $timeTrackingMetrics = Issue::selectRaw('
                sum(estimated_hours) as total_estimated,
                sum(actual_hours) as total_actual,
                avg(estimated_hours) as avg_estimated,
                avg(actual_hours) as avg_actual
            ')
            ->whereNotNull('estimated_hours')
            ->first();

        // Top Labels Used
        $topLabels = DB::table('issue_labels')
            ->select('issue_labels.id', 'issue_labels.name', 'issue_labels.color', DB::raw('count(issue_label_pivot.issue_id) as usage_count'))
            ->leftJoin('issue_label_pivot', 'issue_labels.id', '=', 'issue_label_pivot.issue_label_id')
            ->groupBy('issue_labels.id', 'issue_labels.name', 'issue_labels.color')
            ->having('usage_count', '>', 0)
            ->orderByDesc('usage_count')
            ->limit(10)
            ->get();

        // Average Resolution Time (days)
        $avgResolutionTime = Issue::whereNotNull('closed_at')
            ->selectRaw('avg(TIMESTAMPDIFF(DAY, created_at, closed_at)) as avg_days')
            ->value('avg_days');

        // Recent Activity (last 10 issues)
        $recentIssues = Issue::with(['creator', 'assignee'])
            ->latest()
            ->limit(10)
            ->get();

        return view('admin.issue-reports.index', compact(
            'stats',
            'issuesByStatus',
            'issuesByPriority',
            'issuesByType',
            'issuesCreatedOverTime',
            'issuesClosedOverTime',
            'assigneePerformance',
            'timeTrackingMetrics',
            'topLabels',
            'avgResolutionTime',
            'recentIssues',
            'startDate',
            'endDate'
        ));
    }
}