package engine

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"golang.org/x/net/html"
)

// ProcessFile processes a single HTML file (following Go stdlib pattern like os.ReadFile/WriteFile)
func (e *ContentEngine) ProcessFile(inputPath, outputPath, siteID string, mode ProcessMode) error {
	htmlContent, err := os.ReadFile(inputPath)
	if err != nil {
		return fmt.Errorf("reading file %s: %w", inputPath, err)
	}

	result, err := e.ProcessContent(ContentInput{
		HTML:     htmlContent,
		FilePath: filepath.Base(inputPath),
		SiteID:   siteID,
		Mode:     mode,
	})
	if err != nil {
		return fmt.Errorf("processing content: %w", err)
	}

	return writeHTMLDocument(outputPath, result.Document)
}

// ProcessDirectory processes all HTML files in a directory (following filepath.Walk pattern)
func (e *ContentEngine) ProcessDirectory(inputDir, outputDir, siteID string, mode ProcessMode) error {
	// Create output directory if it doesn't exist
	if err := os.MkdirAll(outputDir, 0755); err != nil {
		return fmt.Errorf("failed to create output directory: %w", err)
	}

	return filepath.Walk(inputDir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}

		// Calculate relative path for output
		relPath, err := filepath.Rel(inputDir, path)
		if err != nil {
			return err
		}
		outputPath := filepath.Join(outputDir, relPath)

		// Handle directories
		if info.IsDir() {
			return os.MkdirAll(outputPath, info.Mode())
		}

		// Process HTML files
		if strings.HasSuffix(strings.ToLower(path), ".html") {
			return e.ProcessFile(path, outputPath, siteID, mode)
		}

		// Copy non-HTML files as-is
		return copyFile(path, outputPath)
	})
}

// writeHTMLDocument writes an HTML document to a file
func writeHTMLDocument(outputPath string, doc *html.Node) error {
	// Create output directory
	if err := os.MkdirAll(filepath.Dir(outputPath), 0755); err != nil {
		return fmt.Errorf("creating output directory: %w", err)
	}

	file, err := os.Create(outputPath)
	if err != nil {
		return fmt.Errorf("creating output file: %w", err)
	}
	defer file.Close()

	return html.Render(file, doc)
}

// copyFile copies a file from src to dst
func copyFile(src, dst string) error {
	// Create directory for destination
	if err := os.MkdirAll(filepath.Dir(dst), 0755); err != nil {
		return err
	}

	// Read source
	data, err := os.ReadFile(src)
	if err != nil {
		return err
	}

	// Write destination
	return os.WriteFile(dst, data, 0644)
}