package gorse

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"time"
)

// EmbeddingConfig embedding服务配置
type EmbeddingConfig struct {
	APIKey string
	URL    string
	Model  string
}

var defaultEmbeddingConfig = EmbeddingConfig{
	APIKey: "sk-ZPN5NMPSqEaOGCPfD2LqndZ5Wwmw3DC4CQgzgKhM35fI3RpD",
	URL:    "https://api.littlelan.cn/v1/embeddings",
	Model:  "BAAI/bge-m3",
}

// SetEmbeddingConfig 设置embedding配置
func SetEmbeddingConfig(apiKey, url, model string) {
	if apiKey != "" {
		defaultEmbeddingConfig.APIKey = apiKey
	}
	if url != "" {
		defaultEmbeddingConfig.URL = url
	}
	if model != "" {
		defaultEmbeddingConfig.Model = model
	}
}

// GetEmbedding 获取文本的embedding
func GetEmbedding(text string) ([]float64, error) {
	type embeddingRequest struct {
		Input string `json:"input"`
		Model string `json:"model"`
	}

	type embeddingResponse struct {
		Data []struct {
			Embedding []float64 `json:"embedding"`
		} `json:"data"`
	}

	reqBody := embeddingRequest{
		Input: text,
		Model: defaultEmbeddingConfig.Model,
	}

	jsonData, err := json.Marshal(reqBody)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal request: %w", err)
	}

	req, err := http.NewRequest("POST", defaultEmbeddingConfig.URL, bytes.NewReader(jsonData))
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", "Bearer "+defaultEmbeddingConfig.APIKey)

	client := &http.Client{Timeout: 30 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode >= 400 {
		body, _ := io.ReadAll(resp.Body)
		return nil, fmt.Errorf("embedding API error: status=%d, body=%s", resp.StatusCode, string(body))
	}

	var result embeddingResponse
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return nil, fmt.Errorf("failed to decode response: %w", err)
	}

	if len(result.Data) == 0 {
		return nil, fmt.Errorf("no embedding returned")
	}

	return result.Data[0].Embedding, nil
}

// InitEmbeddingWithConfig 从应用配置初始化embedding
func InitEmbeddingWithConfig(apiKey, url, model string) {
	if apiKey == "" {
		log.Println("[WARN] Gorse embedding API key not set, using default")
	}
	defaultEmbeddingConfig.APIKey = apiKey
	if url != "" {
		defaultEmbeddingConfig.URL = url
	}
	if model != "" {
		defaultEmbeddingConfig.Model = model
	}
}