package format

import (
	"strings"
)

// FormatEvent converts event data to bytes for appending to a chat log.
// Streaming roles (assistant, reasoning, retry) return only the content chunk;
// the caller is responsible for writing the [[[role]]] header for those.
func FormatEvent(role, name, content, outputFormat string) []byte {
	switch role {
	case "user":
		return []byte(UserTag + "\n" + content + "\n" + EndTag + "\n")
	case "assistant":
		return []byte(content)
	case "reasoning":
		return []byte(content)
	case "call":
		args := strings.Join(strings.Fields(content), " ")
		return []byte(CallDelim(name) + "```\n" + args + "\n```\n" + EndTag + "\n")
	case "tool":
		fence := "```"
		if outputFormat != "" {
			fence += outputFormat
		}
		return []byte(ToolDelim(name) + fence + "\n" + strings.TrimRight(content, "\n") + "\n```\n" + EndTag + "\n")
	case "error":
		return []byte(RoleDelim("error") + "\n" + content + "\n" + EndTag + "\n")
	case "info":
		return []byte(RoleDelim("info") + "\n" + content + "\n" + EndTag + "\n")
	case "retry":
		return []byte(content)
	case "stalled":
		return []byte(RoleDelim("stalled") + "\n" + EndTag + "\n")
	case "maxsteps":
		return []byte(RoleDelim("maxsteps") + "\n" + content + "\n" + EndTag + "\n")
	default:
		return nil
	}
}