// Package renderer provides rendering functionality for sequence diagrams
package renderer

import (
	"fmt"
	"strings"

	"mermaid-go/pkg/ast"
)

// SequenceRenderer renders sequence diagrams back to mermaid syntax
type SequenceRenderer struct{}

// NewSequenceRenderer creates a new sequence renderer
func NewSequenceRenderer() *SequenceRenderer {
	return &SequenceRenderer{}
}

// Render renders a sequence diagram to mermaid syntax
func (r *SequenceRenderer) Render(diagram *ast.SequenceDiagram) (string, error) {
	var builder strings.Builder

	// Start with diagram declaration
	builder.WriteString("sequenceDiagram\n")

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

	// Render participants
	for _, participant := range diagram.Participants {
		builder.WriteString("    ")
		builder.WriteString(string(participant.Type))
		builder.WriteString(" ")
		builder.WriteString(participant.ID)

		if participant.Name != participant.ID {
			builder.WriteString(" as ")
			if strings.Contains(participant.Name, " ") {
				builder.WriteString(fmt.Sprintf("\"%s\"", participant.Name))
			} else {
				builder.WriteString(participant.Name)
			}
		}
		builder.WriteString("\n")
	}

	// Render boxes
	for _, box := range diagram.Boxes {
		builder.WriteString("    box ")
		if strings.Contains(box.Name, " ") {
			builder.WriteString(fmt.Sprintf("\"%s\"", box.Name))
		} else {
			builder.WriteString(box.Name)
		}

		if box.Color != nil {
			builder.WriteString(" ")
			builder.WriteString(*box.Color)
		}

		for _, participant := range box.Participants {
			builder.WriteString(" ")
			builder.WriteString(participant)
		}
		builder.WriteString("\n    end\n")
	}

	// Render activations
	for _, activation := range diagram.Activations {
		builder.WriteString("    ")
		builder.WriteString(string(activation.Type))
		builder.WriteString(" ")
		builder.WriteString(activation.Actor)
		builder.WriteString("\n")
	}

	// Render messages
	for _, message := range diagram.Messages {
		builder.WriteString("    ")
		builder.WriteString(message.From)
		builder.WriteString(" ")
		builder.WriteString(string(message.Type))
		builder.WriteString(" ")
		builder.WriteString(message.To)

		if message.Message != "" {
			builder.WriteString(" : ")
			builder.WriteString(message.Message)
		}
		builder.WriteString("\n")
	}

	// Render notes
	for _, note := range diagram.Notes {
		builder.WriteString("    Note ")
		builder.WriteString(string(note.Placement))
		builder.WriteString(" ")
		builder.WriteString(note.Actor)
		builder.WriteString(" : ")
		builder.WriteString(note.Message)
		builder.WriteString("\n")
	}

	// Render loops
	for _, loop := range diagram.Loops {
		builder.WriteString("    loop ")
		builder.WriteString(loop.Label)
		builder.WriteString("\n")

		for _, message := range loop.Messages {
			builder.WriteString("        ")
			builder.WriteString(message.From)
			builder.WriteString(" ")
			builder.WriteString(string(message.Type))
			builder.WriteString(" ")
			builder.WriteString(message.To)

			if message.Message != "" {
				builder.WriteString(" : ")
				builder.WriteString(message.Message)
			}
			builder.WriteString("\n")
		}

		builder.WriteString("    end\n")
	}

	// Render alts
	for _, alt := range diagram.Alts {
		builder.WriteString("    alt ")
		builder.WriteString(alt.Label)
		builder.WriteString("\n")

		for _, message := range alt.IfMessages {
			builder.WriteString("        ")
			builder.WriteString(message.From)
			builder.WriteString(" ")
			builder.WriteString(string(message.Type))
			builder.WriteString(" ")
			builder.WriteString(message.To)

			if message.Message != "" {
				builder.WriteString(" : ")
				builder.WriteString(message.Message)
			}
			builder.WriteString("\n")
		}

		if len(alt.ElseMessages) > 0 {
			builder.WriteString("    else\n")
			for _, message := range alt.ElseMessages {
				builder.WriteString("        ")
				builder.WriteString(message.From)
				builder.WriteString(" ")
				builder.WriteString(string(message.Type))
				builder.WriteString(" ")
				builder.WriteString(message.To)

				if message.Message != "" {
					builder.WriteString(" : ")
					builder.WriteString(message.Message)
				}
				builder.WriteString("\n")
			}
		}

		builder.WriteString("    end\n")
	}

	// Render opts
	for _, opt := range diagram.Opts {
		builder.WriteString("    opt ")
		builder.WriteString(opt.Label)
		builder.WriteString("\n")

		for _, message := range opt.Messages {
			builder.WriteString("        ")
			builder.WriteString(message.From)
			builder.WriteString(" ")
			builder.WriteString(string(message.Type))
			builder.WriteString(" ")
			builder.WriteString(message.To)

			if message.Message != "" {
				builder.WriteString(" : ")
				builder.WriteString(message.Message)
			}
			builder.WriteString("\n")
		}

		builder.WriteString("    end\n")
	}

	// Render pars
	for _, par := range diagram.Pars {
		builder.WriteString("    par")

		for i, section := range par.Sections {
			if i == 0 {
				// First section starts with par
				builder.WriteString("\n")
			} else {
				// Subsequent sections start with and
				builder.WriteString("    and")
				if section.Label != nil {
					builder.WriteString(" ")
					builder.WriteString(*section.Label)
				}
				builder.WriteString("\n")
			}

			for _, message := range section.Messages {
				builder.WriteString("        ")
				builder.WriteString(message.From)
				builder.WriteString(" ")
				builder.WriteString(string(message.Type))
				builder.WriteString(" ")
				builder.WriteString(message.To)

				if message.Message != "" {
					builder.WriteString(" : ")
					builder.WriteString(message.Message)
				}
				builder.WriteString("\n")
			}
		}

		builder.WriteString("    end\n")
	}

	// Render rects
	for _, rect := range diagram.Rects {
		builder.WriteString("    rect")
		if rect.Color != nil {
			builder.WriteString(" ")
			builder.WriteString(*rect.Color)
		}
		builder.WriteString("\n")

		for _, message := range rect.Messages {
			builder.WriteString("        ")
			builder.WriteString(message.From)
			builder.WriteString(" ")
			builder.WriteString(string(message.Type))
			builder.WriteString(" ")
			builder.WriteString(message.To)

			if message.Message != "" {
				builder.WriteString(" : ")
				builder.WriteString(message.Message)
			}
			builder.WriteString("\n")
		}

		builder.WriteString("    end\n")
	}

	// Render criticals
	for _, critical := range diagram.Criticals {
		builder.WriteString("    critical")
		if critical.Label != "" {
			builder.WriteString(" ")
			builder.WriteString(critical.Label)
		}
		builder.WriteString("\n")

		// Render critical messages
		for _, message := range critical.Messages {
			builder.WriteString("        ")
			builder.WriteString(message.From)
			builder.WriteString(" ")
			builder.WriteString(string(message.Type))
			builder.WriteString(" ")
			builder.WriteString(message.To)

			if message.Message != "" {
				builder.WriteString(" : ")
				builder.WriteString(message.Message)
			}
			builder.WriteString("\n")
		}

		// Render options
		for _, option := range critical.Options {
			builder.WriteString("        option")
			if option.Label != "" {
				builder.WriteString(" ")
				builder.WriteString(option.Label)
			}
			builder.WriteString("\n")

			for _, message := range option.Messages {
				builder.WriteString("            ")
				builder.WriteString(message.From)
				builder.WriteString(" ")
				builder.WriteString(string(message.Type))
				builder.WriteString(" ")
				builder.WriteString(message.To)

				if message.Message != "" {
					builder.WriteString(" : ")
					builder.WriteString(message.Message)
				}
				builder.WriteString("\n")
			}
		}

		builder.WriteString("    end\n")
	}

	// Render breaks
	for _, breakBlock := range diagram.Breaks {
		builder.WriteString("    break")
		if breakBlock.Label != "" {
			builder.WriteString(" ")
			builder.WriteString(breakBlock.Label)
		}
		builder.WriteString("\n")

		for _, message := range breakBlock.Messages {
			builder.WriteString("        ")
			builder.WriteString(message.From)
			builder.WriteString(" ")
			builder.WriteString(string(message.Type))
			builder.WriteString(" ")
			builder.WriteString(message.To)

			if message.Message != "" {
				builder.WriteString(" : ")
				builder.WriteString(message.Message)
			}
			builder.WriteString("\n")
		}

		builder.WriteString("    end\n")
	}

	return builder.String(), nil
}