package ai

import (
	"bytes"
	"context"
	"encoding/json"
	"io"
	"net/http"
	"resume-platform/pkg/config"
	"time"
)

// TongyiProvider 通义千问 AI 供应商实现
type TongyiProvider struct {
	cfg        *config.TongyiConfig // 通义千问配置
	httpClient *http.Client         // HTTP 客户端
}

// NewTongyiProvider 创建通义千问供应商实例
// @param cfg 通义千问配置
// @return *TongyiProvider 供应商实例
// @author sunct
func NewTongyiProvider(cfg *config.TongyiConfig) *TongyiProvider {
	return &TongyiProvider{
		cfg: cfg,
		httpClient: &http.Client{
			Timeout: time.Duration(cfg.Timeout) * time.Second,
		},
	}
}

// GetName 获取供应商名称
// @return string 供应商标识
// @author sunct
func (p *TongyiProvider) GetName() string {
	return "tongyi"
}

// Generate 调用通义千问 API 生成文本
// @param ctx 上下文
// @param prompt 提示词
// @param opts 可选参数
// @return string 生成结果
// @return error 调用错误
// @author sunct
func (p *TongyiProvider) Generate(ctx context.Context, prompt string, opts ...Option) (string, error) {
	options := &Options{
		MaxTokens: p.cfg.MaxTokens,
		Temperature: 0.7,
		TopP: 0.9,
	}
	for _, opt := range opts {
		opt(options)
	}

	body := map[string]interface{}{
		"model": p.getModelName(),
		"messages": []map[string]interface{}{
			{
				"role": "user",
				"content": prompt,
			},
		},
		"max_tokens": options.MaxTokens,
		"temperature": options.Temperature,
		"top_p": options.TopP,
	}

	jsonBody, _ := json.Marshal(body)
	
	req, err := http.NewRequest("POST", p.cfg.BaseURL+"/chat/completions", bytes.NewBuffer(jsonBody))
	if err != nil {
		return "", err
	}
	
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", "Bearer "+p.cfg.APIKey)
	
	resp, err := p.httpClient.Do(req)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	respBody, _ := io.ReadAll(resp.Body)
	
	var result map[string]interface{}
	if err := json.Unmarshal(respBody, &result); err != nil {
		return string(respBody), nil
	}

	if choices, ok := result["choices"].([]interface{}); ok && len(choices) > 0 {
		if choice, ok := choices[0].(map[string]interface{}); ok {
			if message, ok := choice["message"].(map[string]interface{}); ok {
				if content, ok := message["content"].(string); ok {
					return content, nil
				}
			}
		}
	}

	return string(respBody), nil
}

// getModelName 获取模型名称，未配置时使用默认 qwen-turbo
// @return string 模型名
// @author sunct
func (p *TongyiProvider) getModelName() string {
	if p.cfg.Model != "" {
		return p.cfg.Model
	}
	return "qwen-turbo"
}