<?php

namespace App\Controllers;

use App\Models\ClassProgressReportModel;
use App\Models\ClassProgressAttachmentModel;
use App\Models\ClassSectionModel;
use App\Models\StudentClassModel;
use CodeIgniter\Exceptions\PageNotFoundException;
use CodeIgniter\HTTP\ResponseInterface;

class AdminProgressController extends BaseController
{
    protected ClassProgressReportModel $reportModel;
    protected ClassProgressAttachmentModel $attachmentModel;
    protected ClassSectionModel $classSectionModel;
    protected StudentClassModel $studentClassModel;

    public function __construct()
    {
        helper(['url', 'form']);
        $this->reportModel = new ClassProgressReportModel();
        $this->attachmentModel = new ClassProgressAttachmentModel();
        $this->classSectionModel = new ClassSectionModel();
        $this->studentClassModel = new StudentClassModel();
    }

    public function index()
    {
        $filters = [
            'from' => (string) $this->request->getGet('from'),
            'to' => (string) $this->request->getGet('to'),
            'class_section_id' => (string) $this->request->getGet('class_section_id'),
            'status' => (string) $this->request->getGet('status'),
        ];

        $builder = $this->reportModel
            ->select('class_progress_reports.*, cs.class_section_name, CONCAT(IFNULL(u.firstname, ""), " ", IFNULL(u.lastname, "")) AS teacher_name')
            ->join('classSection cs', 'cs.class_section_id = class_progress_reports.class_section_id', 'left')
            ->join('users u', 'u.id = class_progress_reports.teacher_id', 'left');

        if ($filters['from']) {
            $builder->where('week_start >=', $filters['from']);
        }
        if ($filters['to']) {
            $builder->where('week_end <=', $filters['to']);
        }
        if ($filters['class_section_id']) {
            $builder->where('class_progress_reports.class_section_id', (int) $filters['class_section_id']);
        }
        if ($filters['status']) {
            $builder->where('class_progress_reports.status', $filters['status']);
        }

        $rows = $builder->orderBy('week_start', 'DESC')->get()->getResultArray();
        $reportGroups = [];
        foreach ($rows as $row) {
            $row['status_label'] = ClassProgressController::STATUS_OPTIONS[$row['status']] ?? 'Unknown';
            $key = ($row['week_start'] ?? '') . '_' . ($row['class_section_id'] ?? '');
            if ($key === '_') {
                continue;
            }
            if (! isset($reportGroups[$key])) {
                $reportGroups[$key] = [
                    'week_start' => $row['week_start'],
                    'week_end' => $row['week_end'],
                    'class_section_name' => $row['class_section_name'] ?? '',
                    'reports' => [],
                ];
            }
            $reportGroups[$key]['reports'][$row['subject']] = $row;
        }

        $classSections = $this->classSectionModel->getClassSections();
        $studentCounts = $this->studentClassModel->getStudentCountsBySection();
        $filteredSections = array_values(array_filter($classSections, function ($section) use ($studentCounts) {
            $sectionId = (int) ($section['class_section_id'] ?? 0);
            return isset($studentCounts[$sectionId]) && $studentCounts[$sectionId] > 0;
        }));

        return view('admin/class_progress_list', [
            'reportGroups' => $reportGroups,
            'filters' => $filters,
            'classSections' => $filteredSections,
            'statusOptions' => ClassProgressController::STATUS_OPTIONS,
            'subjectSections' => ClassProgressController::SUBJECT_SECTIONS,
        ]);
    }

    public function view($id)
    {
        $row = $this->reportModel
            ->select('class_progress_reports.*, cs.class_section_name, CONCAT(IFNULL(u.firstname, ""), " ", IFNULL(u.lastname, "")) AS teacher_name')
            ->join('classSection cs', 'cs.class_section_id = class_progress_reports.class_section_id', 'left')
            ->join('users u', 'u.id = class_progress_reports.teacher_id', 'left')
            ->find((int) $id);

        if (! $row) {
            throw new PageNotFoundException('Progress report not found.');
        }

        $row['status_label'] = ClassProgressController::STATUS_OPTIONS[$row['status']] ?? 'Unknown';
        $row['flags'] = $this->decodeFlags($row['flags_json']);

        $weeklyReports = $this->reportModel
            ->select('class_progress_reports.*')
            ->where('class_section_id', $row['class_section_id'])
            ->where('week_start', $row['week_start'])
            ->orderBy('subject', 'ASC')
            ->findAll();

        $attachmentMap = $this->loadAttachmentsForReports(array_column($weeklyReports, 'id'));
        foreach ($weeklyReports as &$report) {
            $report['attachments'] = $attachmentMap[$report['id']] ?? [];
            if (empty($report['attachments']) && ! empty($report['attachment_path'])) {
                $report['attachments'][] = [
                    'id' => $report['id'],
                    'name' => basename((string) $report['attachment_path']),
                    'legacy' => true,
                ];
            }
        }

        return view('admin/class_progress_view', [
            'row' => $row,
            'weeklyReports' => $weeklyReports,
            'subjectSections' => ClassProgressController::SUBJECT_SECTIONS,
        ]);
    }

    public function attachment($id)
    {
        $row = $this->reportModel->find((int)$id);
        if (! $row || empty($row['attachment_path'])) {
            throw new PageNotFoundException('Attachment not found.');
        }

        $file = $this->resolveAttachmentFile($row);
        if (! $file) {
            throw new PageNotFoundException('Attachment missing.');
        }

        return $this->response->download($file, null)->setFileName(basename($file));
    }

    public function attachmentFile($id)
    {
        $attachment = $this->attachmentModel->find((int) $id);
        if (! $attachment || empty($attachment['file_path'])) {
            throw new PageNotFoundException('Attachment not found.');
        }

        $file = $this->resolveAttachmentPath($attachment['file_path']);
        if (! $file) {
            throw new PageNotFoundException('Attachment missing.');
        }

        $downloadName = $attachment['original_name'] ?: basename($file);
        return $this->response->download($file, null)->setFileName($downloadName);
    }

    protected function resolveAttachmentFile(array $row): ?string
    {
        $path = trim((string) ($row['attachment_path'] ?? ''));
        if ($path === '') {
            return null;
        }
        return $this->resolveAttachmentPath($path);
    }

    protected function resolveAttachmentPath(string $path): ?string
    {
        $relative = preg_replace('#^writable/uploads/#', '', $path);
        $absolute = WRITEPATH . 'uploads/' . ltrim($relative, '/');
        return is_file($absolute) ? $absolute : null;
    }

    protected function loadAttachmentsForReports(array $reportIds): array
    {
        $reportIds = array_values(array_filter(array_map('intval', $reportIds)));
        if (empty($reportIds)) {
            return [];
        }

        $rows = $this->attachmentModel
            ->whereIn('report_id', $reportIds)
            ->orderBy('id', 'ASC')
            ->findAll();

        $map = [];
        foreach ($rows as $row) {
            $reportId = (int) ($row['report_id'] ?? 0);
            if ($reportId === 0) {
                continue;
            }
            $map[$reportId][] = [
                'id' => (int) $row['id'],
                'name' => $row['original_name'] ?: basename((string) $row['file_path']),
            ];
        }

        return $map;
    }

    protected function decodeFlags(?string $json): array
    {
        if (! $json) {
            return [];
        }

        $flags = json_decode($json, true);
        return is_array($flags) ? $flags : [];
    }
}