<?php

namespace App\RSpade\Integrations\Jqhtml;

use App\RSpade\Integrations\Jqhtml\Jqhtml_Exception_ViewException;

/**
 * JqhtmlWebpackCompiler - Compiles JQHTML templates to JavaScript during bundle build
 *
 * This service handles the compilation of .jqhtml template files into JavaScript
 * during the bundle build process. It uses the @jqhtml/parser NPM package to 
 * perform the compilation and caches the results based on file modification times.
 * 
 * Features:
 * - Uses @jqhtml/parser for template compilation
 * - Caches compiled templates based on file mtime
 * - Throws fatal errors on compilation failures (fail loud)
 * - Integrates with the bundle compilation pipeline
 */
#[Instantiatable]
class JqhtmlWebpackCompiler
{
    /**
     * Path to the jqhtml-compile binary
     */
    protected string $compiler_path;
    
    /**
     * Cache directory for compiled templates
     */
    protected string $cache_dir;
    
    /**
     * Constructor
     */
    public function __construct()
    {
        // Use official jqhtml CLI compiler from npm package
        $this->compiler_path = base_path('node_modules/@jqhtml/parser/bin/jqhtml-compile');
        $this->cache_dir = storage_path('rsx-tmp/jqhtml-cache');

        // Ensure cache directory exists
        if (!is_dir($this->cache_dir)) {
            mkdir($this->cache_dir, 0755, true);
        }

        // Validate compiler exists - MUST exist
        if (!file_exists($this->compiler_path)) {
            throw new \RuntimeException(
                "Official JQHTML CLI compiler not found at: {$this->compiler_path}. " .
                "Run 'npm install @jqhtml/parser@^2.2.59' to install the official CLI compiler."
            );
        }
    }
    
    /**
     * Compile a single JQHTML template file
     * 
     * @param string $file_path Path to .jqhtml file
     * @return string Compiled JavaScript code
     * @throws \RuntimeException On compilation failure
     */
    public function compile_file(string $file_path): string
    {
        if (!file_exists($file_path)) {
            throw new \RuntimeException("JQHTML template not found: {$file_path}");
        }
        
        // Get file modification time for cache key
        $mtime = filemtime($file_path);
        $cache_key = md5($file_path) . '_' . $mtime;
        $cache_file = $this->cache_dir . '/' . $cache_key . '.js';
        
        // Check if cached version exists
        if (file_exists($cache_file)) {
            console_debug("JQHTML", "Using cached JQHTML template: {$file_path}");
            return file_get_contents($cache_file);
        }
        
        console_debug("JQHTML", "Compiling JQHTML template: {$file_path}");

        // Execute official CLI compiler with IIFE format for self-registering templates
        // CRITICAL: Must include --sourcemap for proper error mapping in bundles
        // JQHTML v2.2.65+ uses Mozilla source-map library for reliable concatenation
        // IMPORTANT: Using proc_open() instead of \exec_safe() to handle large template outputs
        // \exec_safe() can truncate output for complex templates due to line-by-line buffering
        $command = sprintf(
            '%s compile %s --format iife --sourcemap',
            escapeshellarg($this->compiler_path),
            escapeshellarg($file_path)
        );

        $descriptors = [
            0 => ['pipe', 'r'],  // stdin
            1 => ['pipe', 'w'],  // stdout
            2 => ['pipe', 'w']   // stderr
        ];

        $process = proc_open($command, $descriptors, $pipes);

        if (!is_resource($process)) {
            throw new \RuntimeException("Failed to execute jqhtml compiler");
        }

        // Close stdin
        fclose($pipes[0]);

        // Set blocking mode to ensure complete reads
        stream_set_blocking($pipes[1], true);
        stream_set_blocking($pipes[2], true);

        // Read stdout and stderr completely in chunks
        // CRITICAL: Use feof() as loop condition to prevent race condition truncation
        // Checking feof() AFTER empty reads can cause 8192-byte truncation bug
        $output_str = '';
        $error_str = '';

        // Read stdout until EOF
        while (!feof($pipes[1])) {
            $chunk = fread($pipes[1], 8192);
            if ($chunk !== false) {
                $output_str .= $chunk;
            }
        }

        // Read stderr until EOF
        while (!feof($pipes[2])) {
            $chunk = fread($pipes[2], 8192);
            if ($chunk !== false) {
                $error_str .= $chunk;
            }
        }

        fclose($pipes[1]);
        fclose($pipes[2]);

        // Get return code
        $return_code = proc_close($process);

        // Combine stdout and stderr for error messages
        if ($return_code !== 0 && !empty($error_str)) {
            $output_str = $error_str . "\n" . $output_str;
        }

        // Check for compilation errors
        if ($return_code !== 0) {
            // Official CLI outputs errors to stderr (captured in stdout with 2>&1)
            // Try multiple error formats

            // Format 1: "at filename:line:column" (newer format)
            if (preg_match('/at [^:]+:(\d+):(\d+)/i', $output_str, $matches)) {
                $line = (int)$matches[1];
                $column = (int)$matches[2];

                throw new Jqhtml_Exception_ViewException(
                    "JQHTML compilation failed:\n{$output_str}",
                    $file_path,
                    $line,
                    $column
                );
            }

            // Format 2: "Error at line X, column Y:" (older format)
            if (preg_match('/Error at line (\d+), column (\d+):/i', $output_str, $matches)) {
                $line = (int)$matches[1];
                $column = (int)$matches[2];

                throw new Jqhtml_Exception_ViewException(
                    "JQHTML compilation failed:\n{$output_str}",
                    $file_path,
                    $line,
                    $column
                );
            }

            // Format 3: No line number found - generic error
            throw new \RuntimeException(
                "JQHTML compilation failed for {$file_path}:\n{$output_str}"
            );
        }

        // Success - the output is the compiled JavaScript
        $compiled_js = $output_str;

        // Don't add any comments - they break sourcemap line offsets
        // Just use the compiler output as-is
        $wrapped_js = $compiled_js;

        // Ensure proper newline at end
        if (!str_ends_with($wrapped_js, "\n")) {
            $wrapped_js .= "\n";
        }

        // Cache the compiled result
        file_put_contents($cache_file, $wrapped_js);

        // Clean up old cache files for this template
        $this->cleanup_old_cache($file_path, $cache_key);

        return $wrapped_js;
    }
    
    /**
     * Compile multiple JQHTML template files
     * 
     * @param array $files Array of file paths
     * @return array Compiled JavaScript code keyed by file path
     */
    public function compile_files(array $files): array
    {
        $compiled = [];
        
        foreach ($files as $file) {
            try {
                $compiled[$file] = $this->compile_file($file);
            } catch (\Exception $e) {
                // FAIL LOUD - don't continue on error
                throw new \RuntimeException(
                    "Failed to compile JQHTML templates: " . $e->getMessage()
                );
            }
        }
        
        return $compiled;
    }
    
    /**
     * Extract component name from file path
     * 
     * @param string $file_path Path to .jqhtml file
     * @return string Component name
     */
    protected function extract_component_name(string $file_path): string
    {
        // Remove base path and extension
        $relative = str_replace(base_path() . '/', '', $file_path);
        $relative = preg_replace('/\.jqhtml$/i', '', $relative);
        
        // Convert path to component name (e.g., rsx/app/components/MyComponent)
        // to MyComponent or components/MyComponent
        $parts = explode('/', $relative);
        
        // Use the filename as the component name
        return basename($relative);
    }
    
    /**
     * Clean up old cache files for a template
     * 
     * @param string $file_path Original template path
     * @param string $current_cache_key Current cache key to keep
     */
    protected function cleanup_old_cache(string $file_path, string $current_cache_key): void
    {
        $file_hash = md5($file_path);
        $pattern = $this->cache_dir . '/' . $file_hash . '_*.js';
        
        foreach (glob($pattern) as $cache_file) {
            $cache_key = basename($cache_file, '.js');
            if ($cache_key !== $current_cache_key) {
                unlink($cache_file);
            }
        }
    }
    
    /**
     * Clear all cached templates
     */
    public function clear_cache(): void
    {
        $pattern = $this->cache_dir . '/*.js';
        foreach (glob($pattern) as $cache_file) {
            unlink($cache_file);
        }
        
        console_debug("JQHTML", "Cleared JQHTML template cache");
    }
    
    /**
     * Get cache statistics
     * 
     * @return array Cache statistics
     */
    public function get_cache_stats(): array
    {
        $pattern = $this->cache_dir . '/*.js';
        $files = glob($pattern);
        
        $total_size = 0;
        foreach ($files as $file) {
            $total_size += filesize($file);
        }
        
        return [
            'cache_dir' => $this->cache_dir,
            'cached_files' => count($files),
            'total_size' => $total_size,
            'total_size_human' => $this->format_bytes($total_size)
        ];
    }
    
    /**
     * Format bytes to human readable
     * 
     * @param int $bytes
     * @return string
     */
    protected function format_bytes(int $bytes): string
    {
        $units = ['B', 'KB', 'MB', 'GB'];
        $i = 0;
        
        while ($bytes >= 1024 && $i < count($units) - 1) {
            $bytes /= 1024;
            $i++;
        }
        
        return round($bytes, 2) . ' ' . $units[$i];
    }
}