package chatgpt

import (
	"chat/globals"
	"chat/utils"
	"fmt"
	"strings"
)

type ChatProps struct {
	Model            string
	Message          []globals.Message
	Token            *int
	PresencePenalty  *float32
	FrequencyPenalty *float32
	Temperature      *float32
	TopP             *float32
	Tools            *globals.FunctionTools
	ToolChoice       *interface{}
	Buffer           utils.Buffer
}

func (c *ChatInstance) GetChatEndpoint(props *ChatProps) string {
	if props.Model == globals.GPT3TurboInstruct {
		return fmt.Sprintf("%s/v1/completions", c.GetEndpoint())
	}
	return fmt.Sprintf("%s/v1/chat/completions", c.GetEndpoint())
}

func (c *ChatInstance) GetCompletionPrompt(messages []globals.Message) string {
	result := ""
	for _, message := range messages {
		result += fmt.Sprintf("%s: %s\n", message.Role, message.Content)
	}
	return result
}

func (c *ChatInstance) GetLatestPrompt(props *ChatProps) string {
	if len(props.Message) == 0 {
		return ""
	}

	return props.Message[len(props.Message)-1].Content
}

func (c *ChatInstance) GetChatBody(props *ChatProps, stream bool) interface{} {
	if props.Model == globals.GPT3TurboInstruct {
		// for completions
		return CompletionRequest{
			Model:    props.Model,
			Prompt:   c.GetCompletionPrompt(props.Message),
			MaxToken: props.Token,
			Stream:   stream,
		}
	}

	return ChatRequest{
		Model:            props.Model,
		Messages:         formatMessages(props),
		MaxToken:         props.Token,
		Stream:           stream,
		PresencePenalty:  props.PresencePenalty,
		FrequencyPenalty: props.FrequencyPenalty,
		Temperature:      props.Temperature,
		TopP:             props.TopP,
		Tools:            props.Tools,
		ToolChoice:       props.ToolChoice,
	}
}

// CreateChatRequest is the native http request body for chatgpt
func (c *ChatInstance) CreateChatRequest(props *ChatProps) (string, error) {
	if globals.IsDalleModel(props.Model) {
		return c.CreateImage(props)
	}

	res, err := utils.Post(
		c.GetChatEndpoint(props),
		c.GetHeader(),
		c.GetChatBody(props, false),
	)

	if err != nil || res == nil {
		return "", fmt.Errorf("chatgpt error: %s", err.Error())
	}

	data := utils.MapToStruct[ChatResponse](res)
	if data == nil {
		return "", fmt.Errorf("chatgpt error: cannot parse response")
	} else if data.Error.Message != "" {
		return "", fmt.Errorf("chatgpt error: %s", data.Error.Message)
	}
	return data.Choices[0].Message.Content, nil
}

// CreateStreamChatRequest is the stream response body for chatgpt
func (c *ChatInstance) CreateStreamChatRequest(props *ChatProps, callback globals.Hook) error {
	if globals.IsDalleModel(props.Model) {
		if url, err := c.CreateImage(props); err != nil {
			return err
		} else {
			return callback(url)
		}
	}

	buf := ""
	cursor := 0
	chunk := ""
	instruct := props.Model == globals.GPT3TurboInstruct

	err := utils.EventSource(
		"POST",
		c.GetChatEndpoint(props),
		c.GetHeader(),
		c.GetChatBody(props, true),
		func(data string) error {
			data, err := c.ProcessLine(props.Buffer, instruct, buf, data)
			chunk += data

			if err != nil {
				if strings.HasPrefix(err.Error(), "chatgpt error") {
					return err
				}

				// error when break line
				buf = buf + data
				return nil
			}

			buf = ""
			if data != "" {
				cursor += 1
				if err := callback(data); err != nil {
					return err
				}
			}
			return nil
		},
	)

	if err != nil {
		return err
	} else if len(chunk) == 0 {
		return fmt.Errorf("empty response")
	}

	return nil
}