<?php

declare(strict_types=1);

namespace App\Services;

/**
 * Petit générateur PDF autonome, volontairement limité aux besoins des plannings.
 * Il utilise les polices standard PDF Helvetica / Helvetica-Bold et ne requiert
 * aucune dépendance Composer.
 */
final class SimplePdf
{
    public const A4_LANDSCAPE_WIDTH = 841.89;
    public const A4_LANDSCAPE_HEIGHT = 595.28;

    /** @var array<int, string> */
    private array $pages = [];
    private string $currentPage = '';

    public function __construct(
        private float $width = self::A4_LANDSCAPE_WIDTH,
        private float $height = self::A4_LANDSCAPE_HEIGHT,
    ) {
        $this->addPage();
    }

    public function width(): float
    {
        return $this->width;
    }

    public function height(): float
    {
        return $this->height;
    }

    public function addPage(): void
    {
        if ($this->currentPage !== '') {
            $this->pages[] = $this->currentPage;
        }
        $this->currentPage = '';
    }

    public function text(float $x, float $y, string $text, float $size = 10, bool $bold = false): void
    {
        $font = $bold ? 'F2' : 'F1';
        $encoded = $this->escapeText($text);
        $pdfY = $this->height - $y;
        $this->currentPage .= sprintf(
            "BT /%s %.2F Tf 1 0 0 1 %.2F %.2F Tm (%s) Tj ET\n",
            $font,
            $size,
            $x,
            $pdfY,
            $encoded
        );
    }

    public function line(float $x1, float $y1, float $x2, float $y2, float $gray = 0.75): void
    {
        $this->currentPage .= sprintf(
            "%.3F G %.2F %.2F m %.2F %.2F l S\n",
            $gray,
            $x1,
            $this->height - $y1,
            $x2,
            $this->height - $y2
        );
    }

    public function rect(float $x, float $y, float $w, float $h, float $strokeGray = 0.75): void
    {
        $this->currentPage .= sprintf(
            "%.3F G %.2F %.2F %.2F %.2F re S\n",
            $strokeGray,
            $x,
            $this->height - $y - $h,
            $w,
            $h
        );
    }

    public function fillRect(float $x, float $y, float $w, float $h, float $gray = 0.95): void
    {
        $this->currentPage .= sprintf(
            "%.3F g %.2F %.2F %.2F %.2F re f 0 g\n",
            $gray,
            $x,
            $this->height - $y - $h,
            $w,
            $h
        );
    }

    public function fillRectColor(float $x, float $y, float $w, float $h, string $hex): void
    {
        [$r, $g, $b] = $this->hexToRgb($hex);
        $this->currentPage .= sprintf(
            "%.3F %.3F %.3F rg %.2F %.2F %.2F %.2F re f 0 g\n",
            $r,
            $g,
            $b,
            $x,
            $this->height - $y - $h,
            $w,
            $h
        );
    }

    public function rectColor(float $x, float $y, float $w, float $h, string $hex, float $lineWidth = 1.0): void
    {
        [$r, $g, $b] = $this->hexToRgb($hex);
        $this->currentPage .= sprintf(
            "%.3F %.3F %.3F RG %.2F w %.2F %.2F %.2F %.2F re S 0 G 1 w\n",
            $r,
            $g,
            $b,
            $lineWidth,
            $x,
            $this->height - $y - $h,
            $w,
            $h
        );
    }

    public function textColor(float $x, float $y, string $text, string $hex, float $size = 10, bool $bold = false): void
    {
        [$r, $g, $b] = $this->hexToRgb($hex);
        $font = $bold ? 'F2' : 'F1';
        $encoded = $this->escapeText($text);
        $pdfY = $this->height - $y;
        $this->currentPage .= sprintf(
            "BT %.3F %.3F %.3F rg /%s %.2F Tf 1 0 0 1 %.2F %.2F Tm (%s) Tj ET 0 g\n",
            $r,
            $g,
            $b,
            $font,
            $size,
            $x,
            $pdfY,
            $encoded
        );
    }

    /**
     * @return string[]
     */
    public function wrap(string $text, float $maxWidth, float $fontSize = 9): array
    {
        $text = trim(preg_replace('/\s+/u', ' ', $text) ?? $text);
        if ($text === '') {
            return [''];
        }

        // Helvetica moyenne : environ 0,52 em par caractère. Une estimation
        // conservatrice évite les débordements sans embarquer les métriques AFM.
        $maxChars = max(4, (int) floor($maxWidth / max(1.0, $fontSize * 0.52)));
        $words = preg_split('/\s+/u', $text) ?: [$text];
        $lines = [];
        $line = '';

        foreach ($words as $word) {
            $candidate = $line === '' ? $word : $line . ' ' . $word;
            if ($this->stringLength($candidate) <= $maxChars) {
                $line = $candidate;
                continue;
            }

            if ($line !== '') {
                $lines[] = $line;
            }

            while ($this->stringLength($word) > $maxChars) {
                $lines[] = $this->stringSlice($word, 0, $maxChars);
                $word = $this->stringSlice($word, $maxChars);
            }
            $line = $word;
        }

        if ($line !== '') {
            $lines[] = $line;
        }

        return $lines ?: [''];
    }

    public function output(): string
    {
        if ($this->currentPage !== '' || $this->pages === []) {
            $this->pages[] = $this->currentPage;
            $this->currentPage = '';
        }

        $objects = [];
        $objects[1] = '<< /Type /Catalog /Pages 2 0 R >>';
        $objects[3] = '<< /Type /Font /Subtype /Type1 /BaseFont /Helvetica /Encoding /WinAnsiEncoding >>';
        $objects[4] = '<< /Type /Font /Subtype /Type1 /BaseFont /Helvetica-Bold /Encoding /WinAnsiEncoding >>';

        $pageObjectIds = [];
        $nextObjectId = 5;

        foreach ($this->pages as $content) {
            $pageObjectId = $nextObjectId++;
            $contentObjectId = $nextObjectId++;
            $pageObjectIds[] = $pageObjectId;

            $objects[$pageObjectId] = sprintf(
                '<< /Type /Page /Parent 2 0 R /MediaBox [0 0 %.2F %.2F] /Resources << /Font << /F1 3 0 R /F2 4 0 R >> >> /Contents %d 0 R >>',
                $this->width,
                $this->height,
                $contentObjectId
            );
            $objects[$contentObjectId] = "<< /Length " . strlen($content) . ">>\nstream\n" . $content . "endstream";
        }

        $kids = implode(' ', array_map(static fn (int $id): string => $id . ' 0 R', $pageObjectIds));
        $objects[2] = sprintf('<< /Type /Pages /Kids [%s] /Count %d >>', $kids, count($pageObjectIds));
        ksort($objects);

        $pdf = "%PDF-1.4\n%\xE2\xE3\xCF\xD3\n";
        $offsets = [0 => 0];

        foreach ($objects as $id => $body) {
            $offsets[$id] = strlen($pdf);
            $pdf .= $id . " 0 obj\n" . $body . "\nendobj\n";
        }

        $xrefOffset = strlen($pdf);
        $maxObjectId = max(array_keys($objects));
        $pdf .= "xref\n0 " . ($maxObjectId + 1) . "\n";
        $pdf .= "0000000000 65535 f \n";
        for ($id = 1; $id <= $maxObjectId; $id++) {
            $offset = $offsets[$id] ?? 0;
            $pdf .= sprintf('%010d 00000 n ', $offset) . "\n";
        }

        $pdf .= "trailer\n<< /Size " . ($maxObjectId + 1) . " /Root 1 0 R >>\n";
        $pdf .= "startxref\n" . $xrefOffset . "\n%%EOF";

        return $pdf;
    }

    private function stringLength(string $value): int
    {
        return function_exists('mb_strlen') ? mb_strlen($value, 'UTF-8') : strlen($value);
    }

    private function stringSlice(string $value, int $start, ?int $length = null): string
    {
        if (function_exists('mb_substr')) {
            return mb_substr($value, $start, $length, 'UTF-8');
        }
        return $length === null ? substr($value, $start) : substr($value, $start, $length);
    }

    /** @return array{0:float,1:float,2:float} */
    private function hexToRgb(string $hex): array
    {
        $hex = ltrim(trim($hex), '#');
        if (strlen($hex) === 3) {
            $hex = $hex[0] . $hex[0] . $hex[1] . $hex[1] . $hex[2] . $hex[2];
        }
        if (!preg_match('/^[0-9a-fA-F]{6}$/', $hex)) {
            $hex = '000000';
        }

        return [
            hexdec(substr($hex, 0, 2)) / 255,
            hexdec(substr($hex, 2, 2)) / 255,
            hexdec(substr($hex, 4, 2)) / 255,
        ];
    }

    private function escapeText(string $text): string
    {
        $converted = function_exists('iconv')
            ? iconv('UTF-8', 'Windows-1252//TRANSLIT//IGNORE', $text)
            : false;
        if ($converted === false) {
            $converted = preg_replace('/[^\x20-\x7E]/', '?', $text) ?? $text;
        }

        return str_replace(
            ['\\', '(', ')', "\r", "\n"],
            ['\\\\', '\\(', '\\)', '', ' '],
            $converted
        );
    }
}