<?php

namespace App\Services;

use App\Models\JobCircular;
use Illuminate\Support\Facades\DB;
use Illuminate\Pagination\LengthAwarePaginator;

class JobCircularService
{
   /**
    * Get all job circulars with optional filters and pagination.
    */
   public function getJobCirculars(array $data): LengthAwarePaginator
   {

      return DB::transaction(function () use ($data) {
         $page = array_key_exists('per_page', $data) ? intval($data['per_page']) : 10;

         $query = JobCircular::query()
            ->when(array_key_exists('search', $data), function ($query) use ($data) {
               return $query->where(function ($q) use ($data) {
                  $q->where('title', 'LIKE', "%{$data['search']}%");
               });
            })
            ->when(array_key_exists('status', $data), function ($query) use ($data) {
               return $query->where('status', $data['status']);
            })
            ->when(array_key_exists('job_type', $data), function ($query) use ($data) {
               return $query->byJobType($data['job_type']);
            })
            ->when(array_key_exists('experience_level', $data), function ($query) use ($data) {
               return $query->byExperienceLevel($data['experience_level']);
            })
            ->when(array_key_exists('work_type', $data), function ($query) use ($data) {
               return $query->byWorkType($data['work_type']);
            })
            ->orderBy('created_at', 'desc');

         return $query->paginate($page);
      }, 5);
   }

   /**
    * Get active job circulars for public display.
    */
   public function getActiveJobCirculars(array $data): LengthAwarePaginator
   {
      return DB::transaction(function () use ($data) {
         $per_page = array_key_exists('per_page', $data) ? intval($data['per_page']) : 10;

         $query = JobCircular::query()
            ->published()
            ->notExpired()
            ->when(array_key_exists('search', $data), function ($query) use ($data) {
               return $query->where(function ($q) use ($data) {
                  $q->where('title', 'LIKE', "%{$data['search']}%");
               });
            })
            ->when(array_key_exists('job_type', $data), function ($query) use ($data) {
               return $query->byJobType($data['job_type']);
            })
            ->when(array_key_exists('experience_level', $data), function ($query) use ($data) {
               return $query->byExperienceLevel($data['experience_level']);
            })
            ->when(array_key_exists('work_type', $data), function ($query) use ($data) {
               return $query->byWorkType($data['work_type']);
            })
            ->orderBy('created_at', 'desc');

         return $query->paginate($per_page);
      }, 5);
   }

   /**
    * Create a new job circular.
    */
   public function createJobCircular(array $data): JobCircular
   {
      return DB::transaction(function () use ($data) {
         return JobCircular::create($data);
      }, 5);
   }

   /**
    * Update an existing job circular.
    */
   public function updateJobCircular(JobCircular $jobCircular, array $data): JobCircular
   {
      return DB::transaction(function () use ($jobCircular, $data) {
         // Set published_at if status is being changed to active for the first time
         if (
            $data['status'] === 'active' &&
            $jobCircular->status !== 'active' &&
            empty($data['published_at'])
         ) {
            $data['published_at'] = now();
         }

         // Clear published_at if status is being changed to draft
         if ($data['status'] === 'draft') {
            $data['published_at'] = null;
         }

         $jobCircular->update($data);

         return $jobCircular->fresh();
      }, 5);
   }

   /**
    * Delete a job circular.
    */
   public function deleteJobCircular(JobCircular $jobCircular): bool
   {
      return DB::transaction(function () use ($jobCircular) {
         return $jobCircular->delete();
      }, 5);
   }

   /**
    * Toggle job circular status between active and draft.
    */
   public function toggleStatus(JobCircular $jobCircular): JobCircular
   {
      return DB::transaction(function () use ($jobCircular) {
         $newStatus = $jobCircular->status === 'active' ? 'draft' : 'active';
         $jobCircular->update(['status' => $newStatus]);
         return $jobCircular->fresh();
      }, 5);
   }

   /**
    * Get job circular statistics.
    */
   public function getStatistics(): array
   {
      return DB::transaction(function () {
         $total = JobCircular::count();
         $active = JobCircular::where('status', 'active')->count();
         $draft = JobCircular::where('status', 'draft')->count();
         $closed = JobCircular::where('status', 'closed')->count();
         $expired = JobCircular::where('application_deadline', '<', now()->format('Y-m-d'))->count();

         return [
            'total' => $total,
            'active' => $active,
            'draft' => $draft,
            'closed' => $closed,
            'expired' => $expired,
         ];
      }, 5);
   }
}