// Package tokenhub 封装 Tokenhub 大模型 API 调用，用于生成每日星座运势与穿搭推荐。
package tokenhub

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

	"git.lzcwy.cn/zhengchiliu/zt-closet-backend/global"
)

const baseURL = "https://tokenhub.tencentmaas.com/v1/chat/completions"

// Client Tokenhub API 客户端。
type Client struct {
	apiKey     string
	model      string
	httpClient *http.Client
}

// NewClient 从全局配置创建客户端。
func NewClient() *Client {
	return &Client{
		apiKey: global.TokenhubSetting.APIKey,
		model:  global.TokenhubSetting.Model,
		httpClient: &http.Client{
			Timeout: 120 * time.Second,
		},
	}
}

// Message 聊天消息。
type Message struct {
	Role    string `json:"role"`
	Content string `json:"content"`
}

// chatResponse Tokenhub chat/completions 外层响应结构（只取需要的字段）。
type chatResponse struct {
	Choices []struct {
		Message struct {
			Content string `json:"content"`
		} `json:"message"`
	} `json:"choices"`
}

// ResponseFormat JSON Schema 响应格式。
type ResponseFormat struct {
	Type       string      `json:"type"`
	JSONSchema *JSONSchema `json:"json_schema"`
}

// JSONSchema 结构化输出定义。
type JSONSchema struct {
	Name   string      `json:"name"`
	Schema interface{} `json:"schema"`
}

// ChatCompletion 调用混元 chat/completions，返回原始响应体。
func (c *Client) ChatCompletion(ctx context.Context, messages []Message, responseFormat *ResponseFormat) ([]byte, error) {
	body := map[string]interface{}{
		"model":    c.model,
		"messages": messages,
	}
	if responseFormat != nil {
		body["response_format"] = responseFormat
	}

	jsonBody, err := json.Marshal(body)
	if err != nil {
		return nil, fmt.Errorf("marshal request: %w", err)
	}

	request, err := http.NewRequestWithContext(ctx, "POST", baseURL, bytes.NewBuffer(jsonBody))
	if err != nil {
		return nil, fmt.Errorf("create request: %w", err)
	}
	request.Header.Set("Authorization", "Bearer "+c.apiKey)
	request.Header.Set("Content-Type", "application/json")

	response, err := c.httpClient.Do(request)
	if err != nil {
		return nil, fmt.Errorf("do request: %w", err)
	}
	defer response.Body.Close()

	data, err := io.ReadAll(response.Body)
	if err != nil {
		return nil, fmt.Errorf("read response: %w", err)
	}

	if response.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("tokenhub api error: status=%d, body=%s", response.StatusCode, string(data))
	}

	return data, nil
}