// Package renderer provides BPMN rendering
package renderer

import (
	"fmt"
	"strings"

	"mermaid-go/pkg/ast"
)

// BPMNRenderer implements BPMN rendering
type BPMNRenderer struct{}

// NewBPMNRenderer creates a new BPMN renderer
func NewBPMNRenderer() *BPMNRenderer {
	return &BPMNRenderer{}
}

// Render renders a BPMN diagram to mermaid syntax
func (r *BPMNRenderer) Render(diagram *ast.BPMNDiagram) (string, error) {
	var result strings.Builder

	// Start with bpmn declaration
	result.WriteString("bpmn\n")

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

	// Render pools
	for _, pool := range diagram.Pools {
		result.WriteString(fmt.Sprintf("    pool %s", pool.ID))
		if pool.Name != pool.ID {
			result.WriteString(fmt.Sprintf("[%s]", pool.Name))
		}
		result.WriteString("\n")
	}

	// Render lanes
	for _, lane := range diagram.Lanes {
		result.WriteString(fmt.Sprintf("    lane %s", lane.ID))
		if lane.Name != lane.ID {
			result.WriteString(fmt.Sprintf("[%s]", lane.Name))
		}
		if lane.Pool != "" {
			result.WriteString(fmt.Sprintf(" in %s", lane.Pool))
		}
		result.WriteString("\n")
	}

	// Render elements
	for _, element := range diagram.Elements {
		result.WriteString(fmt.Sprintf("    %s", element.ID))

		if element.Name != element.ID {
			result.WriteString(fmt.Sprintf("[%s]", element.Name))
		}

		// Add type information if not default
		if element.Type != ast.BPMNElementTask {
			result.WriteString(fmt.Sprintf("(%s)", string(element.Type)))
		}

		result.WriteString("\n")
	}

	// Render flows
	for _, flow := range diagram.Flows {
		result.WriteString(fmt.Sprintf("    %s ", flow.From))

		// Render flow type
		switch flow.Type {
		case ast.BPMNFlowSequence:
			result.WriteString("-->")
		case ast.BPMNFlowMessage:
			result.WriteString("-.->")
		case ast.BPMNFlowAssociation:
			result.WriteString("-.->")
		default:
			result.WriteString("-->")
		}

		result.WriteString(fmt.Sprintf(" %s", flow.To))

		// Add flow name if present
		if flow.Name != nil {
			result.WriteString(fmt.Sprintf(" : %s", *flow.Name))
		}

		result.WriteString("\n")
	}

	return result.String(), nil
}