<?php

namespace App\Http\Controllers;

use App\Models\AcademicYear;
use App\Models\Department;
use App\Models\DocumentType;
use App\Models\SchoolClass;
use App\Models\Student;
use App\Models\StudentExit;
use App\Models\StudentTransfer;
use Illuminate\Support\Collection;
use Illuminate\View\View;

class DashboardController extends Controller
{
    public function __invoke(): View
    {
        $requiredDocumentTypeIds = DocumentType::where('is_active', true)
            ->where('is_required', true)
            ->pluck('id');

        $students = Student::with('documents')->get();

        $completion = $this->calculateCompletion($students, $requiredDocumentTypeIds);

        return view('dashboard', [
            'stats' => [
                'academicYears' => AcademicYear::count(),
                'departments' => Department::count(),
                'classes' => SchoolClass::count(),
                'documentTypes' => DocumentType::count(),
                'students' => Student::count(),
                'studentsDropped' => StudentExit::count(),
                'studentsTransferred' => StudentTransfer::count(),
                'studentsGraduated' => Student::where('status', 'graduated')->count(),
                'studentsCompleteDocuments' => $completion['complete'],
                'studentsIncompleteDocuments' => $completion['incomplete'],
                'studentsVerifiedDocuments' => $completion['verified_complete'],
                'studentsUnverifiedDocuments' => $completion['verified_incomplete'],
            ],
        ]);
    }

    protected function calculateCompletion(Collection $students, Collection $requiredDocumentTypeIds): array
    {
        if ($requiredDocumentTypeIds->isEmpty()) {
            return [
                'complete' => $students->count(),
                'incomplete' => 0,
                'verified_complete' => $students->count(),
                'verified_incomplete' => 0,
            ];
        }

        $complete = 0;
        $verifiedComplete = 0;

        foreach ($students as $student) {
            $requiredDocuments = $student->documents->whereIn('document_type_id', $requiredDocumentTypeIds);

            $uploadedRequired = $requiredDocuments
                ->pluck('document_type_id')
                ->unique()
                ->count();

            $verifiedRequired = $requiredDocuments
                ->where('verification_status', 'valid')
                ->pluck('document_type_id')
                ->unique()
                ->count();

            if ($uploadedRequired >= $requiredDocumentTypeIds->count()) {
                $complete++;
            }

            if ($verifiedRequired >= $requiredDocumentTypeIds->count()) {
                $verifiedComplete++;
            }
        }

        return [
            'complete' => $complete,
            'incomplete' => max($students->count() - $complete, 0),
            'verified_complete' => $verifiedComplete,
            'verified_incomplete' => max($students->count() - $verifiedComplete, 0),
        ];
    }
}