<?php

namespace App\Services;

use App\Models\Certificate;
use App\Models\Program;
use App\Models\Participant;
use App\Models\CertificateTemplate;
use Illuminate\Support\Facades\Storage;
use Intervention\Image\ImageManager;
use Intervention\Image\Drivers\Gd\Driver;
use Intervention\Image\Encoders\JpegEncoder;
use Intervention\Image\Typography\FontFactory;

class CertificateService
{
    private ImageManager $manager;

    public function __construct()
    {
        $this->manager = new ImageManager(new Driver());
    }

    public function generate(Certificate $certificate): void
    {
        $certificate->update(['status' => 'generating']);

        try {
            $certificate->load(['participant', 'template', 'program']);

            $template = $certificate->template;
            if (! $template) {
                throw new \RuntimeException('Template sijil tidak dijumpai.');
            }

            $templatePath = Storage::disk('local')->path($template->image_path);
            if (! file_exists($templatePath)) {
                throw new \RuntimeException('Fail template sijil tidak dijumpai di storage.');
            }

            $image  = $this->manager->decodePath($templatePath);
            $config = $template->config_json ?? [];
            $fields = $config['fields'] ?? [];

            if (isset($fields['name'])) {
                $this->writeText($image, $certificate->participant->name, $fields['name']);
                $this->writeIcBelow($image, $certificate->participant->no_kp, $fields['name']);
            }

            if (isset($fields['certificate_no']) && $certificate->certificate_no) {
                $this->writeText($image, $certificate->certificate_no, $fields['certificate_no']);
            }

            $outputDir  = 'certificates/' . $certificate->program_id;
            $outputFile = $outputDir . '/' . $certificate->uuid . '.jpg';

            Storage::disk('local')->makeDirectory($outputDir);
            $image->encode(new JpegEncoder(90))
                  ->save(Storage::disk('local')->path($outputFile));

            $certificate->update([
                'file_path'    => $outputFile,
                'status'       => 'generated',
                'generated_at' => now(),
                'error_message'=> null,
            ]);
        } catch (\Throwable $e) {
            $certificate->update([
                'status'        => 'failed',
                'error_message' => $e->getMessage(),
            ]);
        }
    }

    public function generatePreview(CertificateTemplate $template, string $sampleName, string $sampleNo = '', ?array $overrideFields = null, string $sampleIc = '800808-08-8888'): string
    {
        $templatePath = Storage::disk('local')->path($template->image_path);
        $image  = $this->manager->decodePath($templatePath);
        $fields = $overrideFields ?? ($template->config_json['fields'] ?? []);

        if (isset($fields['name'])) {
            $this->writeText($image, $sampleName, $fields['name']);
            $this->writeIcBelow($image, $sampleIc, $fields['name']);
        }

        if (isset($fields['certificate_no'])) {
            $this->writeText($image, $sampleNo ?: 'ECT/2025/0001', $fields['certificate_no']);
        }

        return $image->encode(new JpegEncoder(85))->toString();
    }

    // Tulis IC di bawah nama — auto-posisi Y, saiz font dari config atau fallback 70%
    private function writeIcBelow(\Intervention\Image\Interfaces\ImageInterface $image, string $ic, array $nameCfg): void
    {
        $nameFontSize = (int) ($nameCfg['font_size'] ?? 48);
        $icFontSize   = isset($nameCfg['ic_font_size']) && (int) $nameCfg['ic_font_size'] > 0
                        ? (int) $nameCfg['ic_font_size']
                        : (int) round($nameFontSize * 0.7);

        $icY = (int) ($nameCfg['y'] ?? 0) + (int) round($nameFontSize * 1.5);

        $this->writeText($image, $ic, array_merge($nameCfg, [
            'font_size'  => $icFontSize,
            'y'          => $icY,
            'font_file'  => $nameCfg['font_file'] ?? 'DejaVuSans.ttf',
        ]));
    }

    private function writeText(\Intervention\Image\Interfaces\ImageInterface $image, string $text, array $cfg): void
    {
        $fontFile  = $this->resolveFontPath($cfg['font_file'] ?? 'DejaVuSans-Bold.ttf');
        $fontSize  = (int)   ($cfg['font_size']  ?? 48);
        $fontColor = (string)($cfg['font_color'] ?? '#000000');
        $align     = (string)($cfg['align']      ?? 'center');
        $valign    = (string)($cfg['valign']      ?? 'top');
        $x         = (int)   ($cfg['x']          ?? 0);
        $y         = (int)   ($cfg['y']           ?? 0);

        $image->text($text, $x, $y, function (FontFactory $font) use ($fontFile, $fontSize, $fontColor, $align, $valign) {
            $font->filename($fontFile);
            $font->size($fontSize);
            $font->color($fontColor);
            $font->align($align, $valign);  // v4: satu kaedah untuk horizontal + vertical
        });
    }

    private function resolveFontPath(string $filename): string
    {
        $custom = resource_path('fonts/' . $filename);
        if (file_exists($custom)) {
            return $custom;
        }
        return resource_path('fonts/DejaVuSans-Bold.ttf');
    }

    public function buildCertificateNo(Program $program, Participant $participant, int $sequence): string
    {
        $year   = now()->format('Y');
        $prefix = strtoupper(substr(preg_replace('/[^A-Za-z]/', '', $program->title), 0, 4));
        return sprintf('%s/%s/%04d', $prefix, $year, $sequence);
    }
}