package logic

import (
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"time"

	"git.apinb.com/quant/collector/internal/types"
)

// Collector 数据采集器
type Collector struct {
	url        string
	httpClient *http.Client
	lastHash   string
}

// NewCollector 创建新的采集器
func NewCollector(url string) *Collector {
	return &Collector{
		url: url,
		httpClient: &http.Client{
			Timeout: 10 * time.Second,
		},
		lastHash: "",
	}
}

// FetchData 从HTTP接口获取数据
func (c *Collector) FetchData() (*types.StatusData, error) {
	resp, err := c.httpClient.Get(c.url)
	if err != nil {
		return nil, fmt.Errorf("HTTP请求失败: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("HTTP状态码错误: %d", resp.StatusCode)
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("读取响应失败: %w", err)
	}

	var status types.StatusData
	if err := json.Unmarshal(body, &status); err != nil {
		return nil, fmt.Errorf("JSON解析失败: %w", err)
	}

	return &status, nil
}

// CalculateHash 计算数据的SHA256哈希值
func (c *Collector) CalculateHash(status *types.StatusData) (string, error) {
	// 将数据序列化为JSON
	data, err := json.Marshal(status)
	if err != nil {
		return "", fmt.Errorf("序列化数据失败: %w", err)
	}

	// 计算SHA256哈希
	hash := sha256.Sum256(data)
	return hex.EncodeToString(hash[:]), nil
}

// HasChanged 检查数据是否发生变化
func (c *Collector) HasChanged(currentHash string) bool {
	if c.lastHash == "" {
		return true // 第一次采集
	}
	return c.lastHash != currentHash
}

// UpdateHash 更新上次哈希值
func (c *Collector) UpdateHash(hash string) {
	c.lastHash = hash
}

// GetLastHash 获取上次哈希值
func (c *Collector) GetLastHash() string {
	return c.lastHash
}

// CollectAndCheck 采集数据并检查是否变化
func (c *Collector) CollectAndCheck() (*types.StatusData, string, bool, error) {
	// 获取数据
	status, err := c.FetchData()
	if err != nil {
		return nil, "", false, err
	}

	// 计算哈希
	currentHash, err := c.CalculateHash(status)
	if err != nil {
		return nil, "", false, err
	}

	// 检查是否变化
	changed := c.HasChanged(currentHash)

	// 如果变化了，更新哈希
	if changed {
		c.UpdateHash(currentHash)
	}

	return status, currentHash, changed, nil
}