<?php

namespace App\Reports;

use App\Models\Activity;
use App\Reports\Contracts\Report;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Support\Facades\DB;

class ActivitiesPerPeriodReport extends BaseEloquentReport implements Report
{
    public function slug(): string
    {
        return 'activities-per-period';
    }

    public function name(): string
    {
        return 'Aktivnosti po obdobjih';
    }

    public function description(): ?string
    {
        return 'Seštevek aktivnosti po dneh/tednih/mesecih v obdobju.';
    }

    public function inputs(): array
    {
        return [
            ['key' => 'from', 'type' => 'date', 'label' => 'Od', 'nullable' => true],
            ['key' => 'to', 'type' => 'date', 'label' => 'Do', 'nullable' => true],
            ['key' => 'period', 'type' => 'string', 'label' => 'Obdobje (day|week|month)', 'default' => 'day'],
        ];
    }

    public function columns(): array
    {
        return [
            ['key' => 'period', 'label' => 'Obdobje'],
            ['key' => 'activities_count', 'label' => 'Št. aktivnosti'],
        ];
    }

    public function query(array $filters): Builder
    {
        $periodRaw = $filters['period'] ?? 'day';
        $period = in_array($periodRaw, ['day', 'week', 'month'], true) ? $periodRaw : 'day';
        $driver = DB::getDriverName();

        // Build database-compatible period expressions
        if ($driver === 'sqlite') {
            if ($period === 'day') {
                // Use string slice to avoid timezone conversion differences in SQLite
                $selectExpr = DB::raw('SUBSTR(activities.created_at, 1, 10) as period');
                $groupExpr = DB::raw('SUBSTR(activities.created_at, 1, 10)');
                $orderExpr = DB::raw('SUBSTR(activities.created_at, 1, 10)');
            } elseif ($period === 'month') {
                $selectExpr = DB::raw("strftime('%Y-%m-01', activities.created_at) as period");
                $groupExpr = DB::raw("strftime('%Y-%m-01', activities.created_at)");
                $orderExpr = DB::raw("strftime('%Y-%m-01', activities.created_at)");
            } else { // week
                $selectExpr = DB::raw("strftime('%Y-%W', activities.created_at) as period");
                $groupExpr = DB::raw("strftime('%Y-%W', activities.created_at)");
                $orderExpr = DB::raw("strftime('%Y-%W', activities.created_at)");
            }
        } elseif ($driver === 'mysql') {
            if ($period === 'day') {
                $selectExpr = DB::raw('DATE(activities.created_at) as period');
                $groupExpr = DB::raw('DATE(activities.created_at)');
                $orderExpr = DB::raw('DATE(activities.created_at)');
            } elseif ($period === 'month') {
                $selectExpr = DB::raw("DATE_FORMAT(activities.created_at, '%Y-%m-01') as period");
                $groupExpr = DB::raw("DATE_FORMAT(activities.created_at, '%Y-%m-01')");
                $orderExpr = DB::raw("DATE_FORMAT(activities.created_at, '%Y-%m-01')");
            } else { // week
                // ISO week-year-week number for grouping; adequate for summary grouping
                $selectExpr = DB::raw("DATE_FORMAT(activities.created_at, '%x-%v') as period");
                $groupExpr = DB::raw("DATE_FORMAT(activities.created_at, '%x-%v')");
                $orderExpr = DB::raw("DATE_FORMAT(activities.created_at, '%x-%v')");
            }
        } else { // postgres and others supporting date_trunc
            $selectExpr = DB::raw("date_trunc('".$period."', activities.created_at) as period");
            $groupExpr = DB::raw("date_trunc('".$period."', activities.created_at)");
            $orderExpr = DB::raw("date_trunc('".$period."', activities.created_at)");
        }

        return Activity::query()
            ->when(! empty($filters['from']), fn ($q) => $q->whereDate('activities.created_at', '>=', $filters['from']))
            ->when(! empty($filters['to']), fn ($q) => $q->whereDate('activities.created_at', '<=', $filters['to']))
            ->groupBy($groupExpr)
            ->orderBy($orderExpr)
            ->select($selectExpr)
            ->selectRaw('COUNT(*) as activities_count');
    }
}