// Copyright 2023 The casbin Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package model

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"strings"

	"github.com/sashabaranov/go-openai"
)

type LocalModelProvider struct {
	typ              string
	subType          string
	deploymentName   string
	secretKey        string
	temperature      float32
	topP             float32
	frequencyPenalty float32
	presencePenalty  float32
	providerUrl      string
	apiVersion       string
}

func NewLocalModelProvider(typ string, subType string, secretKey string, temperature float32, topP float32, frequencyPenalty float32, presencePenalty float32, providerUrl string) (*LocalModelProvider, error) {
	p := &LocalModelProvider{
		typ:              typ,
		subType:          subType,
		secretKey:        secretKey,
		temperature:      temperature,
		topP:             topP,
		frequencyPenalty: frequencyPenalty,
		presencePenalty:  presencePenalty,
		providerUrl:      providerUrl,
	}
	return p, nil
}

func getLocalClientFromUrl(authToken string, url string) *openai.Client {
	config := openai.DefaultConfig(authToken)
	config.BaseURL = url

	c := openai.NewClientWithConfig(config)
	return c
}

func (p *LocalModelProvider) QueryText(question string, writer io.Writer, builder *strings.Builder) error {
	var client *openai.Client
	if p.typ == "Local" {
		client = getLocalClientFromUrl(p.secretKey, p.providerUrl)
	} else if p.typ == "Azure" {
		client = getAzureClientFromToken(p.subType, p.deploymentName, p.secretKey, p.providerUrl, p.apiVersion)
	}

	ctx := context.Background()
	flusher, ok := writer.(http.Flusher)
	if !ok {
		return fmt.Errorf("writer does not implement http.Flusher")
	}

	model := p.subType
	temperature := p.temperature
	topP := p.topP
	frequencyPenalty := p.frequencyPenalty
	presencePenalty := p.presencePenalty

	respStream, err := client.CreateChatCompletionStream(
		ctx,
		openai.ChatCompletionRequest{
			Model: model,
			Messages: []openai.ChatCompletionMessage{
				{
					Role:    openai.ChatMessageRoleUser,
					Content: question,
				},
			},
			Stream:           true,
			Temperature:      temperature,
			TopP:             topP,
			FrequencyPenalty: frequencyPenalty,
			PresencePenalty:  presencePenalty,
		},
	)
	if err != nil {
		return err
	}
	defer respStream.Close()

	isLeadingReturn := true
	for {
		completion, streamErr := respStream.Recv()
		if streamErr != nil {
			if streamErr == io.EOF {
				break
			}
			return streamErr
		}

		data := completion.Choices[0].Delta.Content
		if isLeadingReturn && len(data) != 0 {
			if strings.Count(data, "\n") == len(data) {
				continue
			} else {
				isLeadingReturn = false
			}
		}

		// Write the streamed data as Server-Sent Events
		if _, err = fmt.Fprintf(writer, "event: message\ndata: %s\n\n", data); err != nil {
			return err
		}
		flusher.Flush()
		// Append the response to the strings.Builder
		builder.WriteString(data)
	}

	return nil
}