package parser

import "encoding/json"

type StreamParser func(line string)

func CreateStreamParser(onText func(string), onDone func()) StreamParser {
	accumulated := ""
	done := false

	return func(line string) {
		if done {
			return
		}

		var obj struct {
			Type    string `json:"type"`
			Subtype string `json:"subtype"`
			Message *struct {
				Content []struct {
					Type string `json:"type"`
					Text string `json:"text"`
				} `json:"content"`
			} `json:"message"`
		}

		if err := json.Unmarshal([]byte(line), &obj); err != nil {
			return
		}

		if obj.Type == "assistant" && obj.Message != nil {
			text := ""
			for _, p := range obj.Message.Content {
				if p.Type == "text" && p.Text != "" {
					text += p.Text
				}
			}
			if text == "" {
				return
			}
			if text == accumulated {
				return
			}
			if len(accumulated) > 0 && len(text) > len(accumulated) && text[:len(accumulated)] == accumulated {
				delta := text[len(accumulated):]
				if delta != "" {
					onText(delta)
				}
				accumulated = text
			} else {
				onText(text)
				accumulated += text
			}
		}

		if obj.Type == "result" && obj.Subtype == "success" {
			done = true
			onDone()
		}
	}
}