<?php

namespace App\Services;

use App\Models\AnalyticsSession;
use App\Models\PageView;
use App\Models\Visitor;
use App\Models\Website;
use Illuminate\Support\Carbon;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\DB;

class AnalyticsQueryService
{
    public function __construct(
        private readonly Website $website,
        private readonly Carbon $from,
        private readonly Carbon $to,
    ) {}

    public static function for(Website $website, Carbon $from, Carbon $to): self
    {
        return new self($website, $from->startOfDay(), $to->endOfDay());
    }

    // ---- Summary Metrics ----

    public function totalPageViews(): int
    {
        return PageView::where('website_id', $this->website->id)
            ->whereBetween('viewed_at', [$this->from, $this->to])
            ->count();
    }

    public function uniqueVisitors(): int
    {
        return PageView::where('website_id', $this->website->id)
            ->whereBetween('viewed_at', [$this->from, $this->to])
            ->distinct('visitor_id')
            ->count('visitor_id');
    }

    public function totalSessions(): int
    {
        return AnalyticsSession::where('website_id', $this->website->id)
            ->whereBetween('started_at', [$this->from, $this->to])
            ->count();
    }

    public function bounceRate(): float
    {
        $total = $this->totalSessions();
        if ($total === 0) {
            return 0;
        }

        $bounced = AnalyticsSession::where('website_id', $this->website->id)
            ->whereBetween('started_at', [$this->from, $this->to])
            ->where('is_bounce', true)
            ->count();

        return round(($bounced / $total) * 100, 1);
    }

    public function avgSessionDuration(): float
    {
        return round(
            (float) AnalyticsSession::where('website_id', $this->website->id)
                ->whereBetween('started_at', [$this->from, $this->to])
                ->avg('duration') ?? 0,
        );
    }

    public function avgPagesPerSession(): float
    {
        return round(
            (float) AnalyticsSession::where('website_id', $this->website->id)
                ->whereBetween('started_at', [$this->from, $this->to])
                ->avg('pages_count') ?? 0,
            1,
        );
    }

    public function summary(): array
    {
        return [
            'page_views' => $this->totalPageViews(),
            'visitors' => $this->uniqueVisitors(),
            'sessions' => $this->totalSessions(),
            'bounce_rate' => $this->bounceRate(),
            'avg_duration' => $this->avgSessionDuration(),
            'avg_pages' => $this->avgPagesPerSession(),
        ];
    }

    // ---- Time Series ----

    public function visitorsOverTime(): Collection
    {
        $days = $this->from->diffInDays($this->to);
        $groupFormat = $days <= 2 ? '%Y-%m-%d %H:00' : '%Y-%m-%d';
        $carbonFormat = $days <= 2 ? 'Y-m-d H:00' : 'Y-m-d';

        $pageViews = PageView::where('website_id', $this->website->id)
            ->whereBetween('viewed_at', [$this->from, $this->to])
            ->select(
                DB::raw("strftime('{$groupFormat}', viewed_at) as period"),
                DB::raw('COUNT(*) as page_views'),
                DB::raw('COUNT(DISTINCT visitor_id) as visitors'),
            )
            ->groupBy('period')
            ->orderBy('period')
            ->get()
            ->keyBy('period');

        $sessions = AnalyticsSession::where('website_id', $this->website->id)
            ->whereBetween('started_at', [$this->from, $this->to])
            ->select(
                DB::raw("strftime('{$groupFormat}', started_at) as period"),
                DB::raw('COUNT(*) as sessions'),
            )
            ->groupBy('period')
            ->orderBy('period')
            ->get()
            ->keyBy('period');

        $periods = collect();
        $cursor = $this->from->copy();
        $increment = $days <= 2 ? 'addHour' : 'addDay';

        while ($cursor->lte($this->to)) {
            $key = $cursor->format($carbonFormat);
            $pv = $pageViews->get($key);
            $sess = $sessions->get($key);

            $periods->push([
                'period' => $key,
                'page_views' => $pv ? $pv->page_views : 0,
                'visitors' => $pv ? $pv->visitors : 0,
                'sessions' => $sess ? $sess->sessions : 0,
            ]);

            $cursor->$increment();
        }

        return $periods;
    }

    // ---- Real-Time ----

    public static function activeVisitors(Website $website, int $minutes = 5): int
    {
        return AnalyticsSession::where('website_id', $website->id)
            ->where('ended_at', '>=', Carbon::now()->subMinutes($minutes))
            ->distinct('visitor_id')
            ->count('visitor_id');
    }
}