// Package renderer provides Packet diagram rendering
package renderer

import (
	"fmt"
	"strings"

	"mermaid-go/pkg/ast"
)

// PacketRenderer implements Packet diagram rendering
type PacketRenderer struct{}

// NewPacketRenderer creates a new Packet renderer
func NewPacketRenderer() *PacketRenderer {
	return &PacketRenderer{}
}

// Render renders a Packet diagram to mermaid syntax
func (r *PacketRenderer) Render(diagram *ast.PacketDiagram) (string, error) {
	var result strings.Builder

	// Start with packet keyword
	result.WriteString("packet\n")

	// Add title if present
	if diagram.Title != nil {
		result.WriteString(fmt.Sprintf("  title %s\n", *diagram.Title))
	}

	// Render packets
	for _, packet := range diagram.Packets {
		result.WriteString(fmt.Sprintf("  %s", packet.Label))
		if packet.Type != "" {
			result.WriteString(fmt.Sprintf(" %s", packet.Type))
		}
		if packet.Protocol != nil {
			result.WriteString(fmt.Sprintf(" %s", *packet.Protocol))
		}
		result.WriteString("\n")
	}

	// Render flows
	for _, flow := range diagram.Flows {
		result.WriteString(fmt.Sprintf("  %s --> %s", flow.From, flow.To))
		if flow.Protocol != nil {
			result.WriteString(fmt.Sprintf(" %s", *flow.Protocol))
		}
		if flow.Label != nil {
			result.WriteString(fmt.Sprintf(" : %s", *flow.Label))
		}
		result.WriteString("\n")
	}

	return result.String(), nil
}