// Package exporter provides diagram export functionality
package exporter

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

	"mermaid-go/pkg/ast"
)

// ExportFormat represents the export format
type ExportFormat string

const (
	FormatSVG ExportFormat = "svg"
)

// ExportOptions contains export configuration
type ExportOptions struct {
	Format ExportFormat
	Width  int
	Height int
	DPI    int
	Theme  string
}

// DefaultExportOptions returns default export options
func DefaultExportOptions() *ExportOptions {
	return &ExportOptions{
		Format: FormatSVG,
		Width:  800,
		Height: 600,
		DPI:    96,
		Theme:  "default",
	}
}

// DiagramExporter provides unified diagram export functionality
type DiagramExporter struct {
	svgExporter *SVGExporter
}

// NewDiagramExporter creates a new diagram exporter
func NewDiagramExporter() *DiagramExporter {
	return &DiagramExporter{
		svgExporter: NewSVGExporter(),
	}
}

// Export exports a diagram with the given options
func (e *DiagramExporter) Export(diagram ast.Diagram, options *ExportOptions) ([]byte, error) {
	if options == nil {
		options = DefaultExportOptions()
	}

	switch options.Format {
	case FormatSVG:
		return e.exportSVG(diagram, options)
	default:
		return nil, fmt.Errorf("unsupported export format: %s", options.Format)
	}
}

// ExportToFile exports a diagram to a file
func (e *DiagramExporter) ExportToFile(diagram ast.Diagram, filename string, options *ExportOptions) error {
	// Infer format from filename if not specified
	if options == nil {
		options = DefaultExportOptions()
		ext := strings.ToLower(filepath.Ext(filename))
		switch ext {
		case ".svg":
			options.Format = FormatSVG
		default:
			options.Format = FormatSVG
		}
	}

	data, err := e.Export(diagram, options)
	if err != nil {
		return fmt.Errorf("failed to export diagram: %w", err)
	}

	err = os.WriteFile(filename, data, 0644)
	if err != nil {
		return fmt.Errorf("failed to write file: %w", err)
	}

	return nil
}

// ExportToWriter exports a diagram to an io.Writer
func (e *DiagramExporter) ExportToWriter(diagram ast.Diagram, writer io.Writer, options *ExportOptions) error {
	data, err := e.Export(diagram, options)
	if err != nil {
		return fmt.Errorf("failed to export diagram: %w", err)
	}

	_, err = writer.Write(data)
	if err != nil {
		return fmt.Errorf("failed to write data: %w", err)
	}

	return nil
}

// exportSVG exports to SVG format
func (e *DiagramExporter) exportSVG(diagram ast.Diagram, options *ExportOptions) ([]byte, error) {
	e.svgExporter.SetSize(options.Width, options.Height)
	e.svgExporter.SetTheme(options.Theme)

	svg, err := e.svgExporter.ExportToSVG(diagram)
	if err != nil {
		return nil, err
	}

	return []byte(svg), nil
}

// GetSupportedFormats returns supported export formats
func (e *DiagramExporter) GetSupportedFormats() []ExportFormat {
	return []ExportFormat{FormatSVG}
}

// GetSupportedDiagramTypes returns supported diagram types for export
func (e *DiagramExporter) GetSupportedDiagramTypes() []ast.DiagramType {
	return []ast.DiagramType{
		ast.DiagramTypeFlowchart,
		ast.DiagramTypeSequence,
		ast.DiagramTypeClassDiagram,
		ast.DiagramTypeStateDiagram,
		ast.DiagramTypeERDiagram,
		ast.DiagramTypePie,
		ast.DiagramTypeGantt,
		ast.DiagramTypeTimeline,
		ast.DiagramTypeUserJourney,
		ast.DiagramTypeArchitecture,
		ast.DiagramTypeOrganization,
		ast.DiagramTypeBPMN,
	}
}

// IsFormatSupported checks if a format is supported
func (e *DiagramExporter) IsFormatSupported(format ExportFormat) bool {
	for _, f := range e.GetSupportedFormats() {
		if f == format {
			return true
		}
	}
	return false
}

// IsDiagramTypeSupported checks if a diagram type is supported for export
func (e *DiagramExporter) IsDiagramTypeSupported(diagramType ast.DiagramType) bool {
	for _, dt := range e.GetSupportedDiagramTypes() {
		if dt == diagramType {
			return true
		}
	}
	return false
}