<?php

declare(strict_types=1);

namespace App\Framework\Console\Components\Parsers;

use App\Framework\Console\Components\EventBuffer;
use App\Framework\Console\Components\MouseEvent;

/**
 * Isolated mouse event parser.
 * Handles SGR mouse events (\e[<b;x;yM or \e[<b;x;ym)
 */
final readonly class MouseEventParser
{
    private const int MAX_BUFFER_SIZE = 20;
    private const int TIMEOUT_MS = 10;
    private const int MAX_X = 1000;
    private const int MAX_Y = 1000;

    public function __construct(
        private EventBuffer $eventBuffer
    ) {
    }

    /**
     * Parse mouse event from sequence prefix \e[<
     */
    public function parse(string $prefix): ?MouseEvent
    {
        $buffer = '';
        $timeout = self::TIMEOUT_MS;
        $startTime = microtime(true) * 1000;

        // Read until we get 'M' or 'm'
        while (true) {
            $char = fgetc(STDIN);
            if ($char === false) {
                // Check timeout
                $elapsed = (microtime(true) * 1000) - $startTime;
                if ($elapsed > $timeout) {
                    // Timeout - store partial sequence for retry
                    if (strlen($prefix . $buffer) > 0) {
                        $this->eventBuffer->storePartialSequence($prefix . $buffer);
                    }
                    return null;
                }
                usleep(1000); // 1ms
                continue;
            }

            $buffer .= $char;

            // Mouse event ends with 'M' (press) or 'm' (release)
            if ($char === 'M' || $char === 'm') {
                break;
            }

            // Safety: limit buffer size
            if (strlen($buffer) > self::MAX_BUFFER_SIZE) {
                return null;
            }
        }

        // Parse format: b;x;y where b is button code, x and y are coordinates
        $data = substr($buffer, 0, -1);
        $parts = explode(';', $data);

        if (count($parts) < 3) {
            // Invalid mouse event format
            return null;
        }

        $buttonCode = (int) $parts[0];
        $x = (int) $parts[1];
        $y = (int) $parts[2];
        
        // Validate coordinates
        if ($x < 1 || $y < 1 || $x > self::MAX_X || $y > self::MAX_Y) {
            // Invalid coordinates, likely corrupted
            return null;
        }

        // Decode button and modifiers
        $button = $buttonCode & 0x03;
        $shift = ($buttonCode & 0x04) !== 0;
        $alt = ($buttonCode & 0x08) !== 0;
        $ctrl = ($buttonCode & 0x10) !== 0;

        // Handle scroll events (button codes 64 and 65)
        if ($buttonCode >= 64 && $buttonCode <= 65) {
            $button = $buttonCode;
        } elseif (($buttonCode & 0x20) !== 0) {
            // Mouse move (button code 32 or bit 5 set)
            $button = $buttonCode;
        }

        $pressed = $buffer[-1] === 'M';

        return new MouseEvent(
            x: $x,
            y: $y,
            button: $button,
            pressed: $pressed,
            shift: $shift,
            ctrl: $ctrl,
            alt: $alt
        );
    }

    /**
     * Check if sequence is a mouse event prefix
     */
    public function isMouseEventPrefix(string $sequence): bool
    {
        return str_starts_with($sequence, "\033[<");
    }
}