<?php

declare(strict_types=1);

namespace App\Http\Controllers;

use App\Models\Insight;
use App\Models\Subject;
use App\Models\TokenUsage;
use App\Models\UserSubject;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;
use Illuminate\View\View;

/**
 * Controller for the main user dashboard.
 * Displays insights, statistics, token usage, and charts.
 */
class DashboardController extends Controller
{
    /**
     * Display the user dashboard with insights and statistics.
     */
    public function index(Request $request): View
    {
        /** @var \App\Models\User $user */
        $user = Auth::user();

        // Basic statistics
        $subjectsCount = UserSubject::where('user_id', $user->id)->count();
        $activeSubjectsCount = UserSubject::where('user_id', $user->id)
            ->where('is_active', true)
            ->count();
        $insightsCount = Insight::where('user_id', $user->id)->count();

        // Token usage statistics
        $totalInputTokens = TokenUsage::where('user_id', $user->id)->sum('input_tokens');
        $totalOutputTokens = TokenUsage::where('user_id', $user->id)->sum('output_tokens');
        $totalTokens = $totalInputTokens + $totalOutputTokens;

        // Recent insights (last 10)
        /** @var \Illuminate\Database\Eloquent\Collection<int, Insight> $recentInsights */
        $recentInsights = Insight::where('user_id', $user->id)
            ->with('subject')
            ->orderByDesc('created_at')
            ->take(10)
            ->get();

        // Active subjects with schedules
        /** @var \Illuminate\Database\Eloquent\Collection<int, UserSubject> $activeSubjects */
        $activeSubjects = UserSubject::where('user_id', $user->id)
            ->where('is_active', true)
            ->with('subject')
            ->get();

        // Token usage chart data (last 30 days)
        $tokenChartData = $this->getTokenChartData($user->id);

        // Insights per subject chart data
        $subjectChartData = $this->getSubjectChartData($user->id);

        // Weekly activity data
        $weeklyActivity = $this->getWeeklyActivity($user->id);

        return view('dashboard.index', compact(
            'subjectsCount',
            'activeSubjectsCount',
            'insightsCount',
            'totalInputTokens',
            'totalOutputTokens',
            'totalTokens',
            'recentInsights',
            'activeSubjects',
            'tokenChartData',
            'subjectChartData',
            'weeklyActivity'
        ));
    }

    /**
     * Get token usage data for charts (last 30 days).
     *
     * @return array<string, mixed>
     */
    private function getTokenChartData(int $userId): array
    {
        $days = 30;
        $data = [];

        for ($i = $days - 1; $i >= 0; $i--) {
            $date = now()->subDays($i)->format('Y-m-d');
            $dailyUsage = TokenUsage::where('user_id', $userId)
                ->whereDate('created_at', $date)
                ->selectRaw('COALESCE(SUM(input_tokens), 0) as input_tokens')
                ->selectRaw('COALESCE(SUM(output_tokens), 0) as output_tokens')
                ->first();

            $data['labels'][] = now()->subDays($i)->format('d/m');
            $data['input'][] = (int) ($dailyUsage->input_tokens ?? 0);
            $data['output'][] = (int) ($dailyUsage->output_tokens ?? 0);
        }

        return $data;
    }

    /**
     * Get insights per subject for chart data.
     *
     * @return array<string, mixed>
     */
    private function getSubjectChartData(int $userId): array
    {
        $insightsBySubject = Insight::where('user_id', $userId)
            ->selectRaw('subject_id, COUNT(*) as total')
            ->groupBy('subject_id')
            ->with('subject')
            ->get();

        $data = [
            'labels' => [],
            'values' => [],
        ];

        foreach ($insightsBySubject as $item) {
            $data['labels'][] = $item->subject?->name ?? __('Unknown');
            $data['values'][] = (int) $item->total;
        }

        return $data;
    }

    /**
     * Get weekly activity data (insights per day of week).
     *
     * @return array<string, mixed>
     */
    private function getWeeklyActivity(int $userId): array
    {
        $daysOfWeek = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'];
        $data = [
            'labels' => $daysOfWeek,
            'values' => [],
        ];

        foreach (range(0, 6) as $day) {
            $count = Insight::where('user_id', $userId)
                ->whereRaw('DAYOFWEEK(created_at) = ?', [$day + 1])
                ->count();
            $data['values'][] = $count;
        }

        return $data;
    }
}