fix query issue for dashboar widget

[theihasan]

No description provided.

[gemini-code-assist]

Summary of Changes

Hello @theihasan, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request focuses on enhancing the efficiency of the JobsByCategoryChart dashboard widget. It addresses a critical performance issue by overhauling the data retrieval mechanism within the widget's data generation methods. The changes consolidate multiple individual database calls into fewer, more efficient queries, which will result in a more responsive and performant user experience when viewing the dashboard.

Highlights

• Performance Optimization: The primary goal of this pull request is to significantly improve the performance of the dashboard widget by optimizing its database queries.
• N+1 Query Resolution: The previous approach, which involved executing a separate database query for each job category to retrieve its data, has been replaced with a single, highly optimized query that fetches all necessary data in one go, effectively resolving the N+1 query problem.
• Refactored Data Retrieval Logic: Both the getData() and getFallbackData() methods have been refactored to pre-fetch aggregated job data efficiently and then process this data in memory to construct the chart datasets, leading to reduced database load and faster rendering.

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[gemini-code-assist]

Code Review

This pull request refactors queries in the JobsByCategoryChart widget to improve performance by addressing N+1 issues. The strategy of consolidating database calls into a single query is a significant improvement. My review includes two main points: first, a fix for a new N+1 query that was inadvertently introduced in getData(), and second, a correction for a potential bug in getFallbackData() related to the use of a database-specific date function that could lead to incorrect data. Applying these suggestions will help ensure the optimizations are both effective and reliable.

[gemini-code-assist]

The Trend query inside the foreach loop causes an N+1 query problem, as it's executed for every category. This query should be moved outside the loop to be executed only once, improving performance significantly.

            // Build data array matching the trend format
            $trendData = Trend::query(JobListing::query())
                ->between(
                    start: $startDate,
                    end: $endDate,
                )
                ->perWeek()
                ->count();

            // Generate datasets for each category using the pre-fetched data
            foreach ($topCategories as $index => $category) {
                $categoryData = $jobData->get($category->id, collect());

                // Create a map of week -> count for this category
                $weekCounts = $categoryData->pluck('count', 'date_week');

                $data = $trendData->map(function (TrendValue $value) use ($weekCounts) {
                    $week = \Carbon\Carbon::parse($value->date)->format('Y-W');

                    return $weekCounts->get($week, 0);
                })->toArray();

                $datasets[] = [
                    'label' => $category->name,
                    'data' => $data,
                    'borderColor' => $colors[$index % count($colors)],
                    'backgroundColor' => $colors[$index % count($colors)].'20',
                    'tension' => 0.3,
                ];
            }

[gemini-code-assist]

The WEEK(created_at) function in MySQL has a default behavior that can be dependent on the default_week_format system variable. This can lead to inconsistencies between the week number calculated by the database and the one calculated by Carbon ($weekStart->week), which is ISO-8601 compliant. To ensure correctness and prevent potential bugs, it's best to explicitly specify the mode for the WEEK() function. Using mode 3 makes it compatible with the ISO 8601 standard, which is what Carbon's ->week property uses.

                WEEK(created_at, 3) as week_num,