// Package http 实现通过 HTTP API 调用 Python 服务的清洗器
package http

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"mime/multipart"
	"net/http"
	"os"
	"path/filepath"
	"time"

	"billai-server/adapter"
)

// CleanRequest HTTP 清洗请求
type CleanRequest struct {
	InputPath  string `json:"input_path"`
	OutputPath string `json:"output_path"`
	Year       string `json:"year,omitempty"`
	Month      string `json:"month,omitempty"`
	Start      string `json:"start,omitempty"`
	End        string `json:"end,omitempty"`
	Format     string `json:"format,omitempty"`
	BillType   string `json:"bill_type,omitempty"`
}

// CleanResponse HTTP 清洗响应
type CleanResponse struct {
	Success    bool   `json:"success"`
	BillType   string `json:"bill_type"`
	Message    string `json:"message"`
	OutputPath string `json:"output_path,omitempty"`
}

// ErrorResponse 错误响应
type ErrorResponse struct {
	Detail string `json:"detail"`
}

// Cleaner 通过 HTTP API 调用 Python 服务的清洗器实现
type Cleaner struct {
	baseURL    string       // Python 服务基础 URL
	httpClient *http.Client // HTTP 客户端
}

// NewCleaner 创建 HTTP 清洗器
func NewCleaner(baseURL string) *Cleaner {
	return &Cleaner{
		baseURL: baseURL,
		httpClient: &http.Client{
			Timeout: 60 * time.Second, // 清洗可能需要较长时间
		},
	}
}

// NewCleanerWithClient 使用自定义 HTTP 客户端创建清洗器
func NewCleanerWithClient(baseURL string, client *http.Client) *Cleaner {
	return &Cleaner{
		baseURL:    baseURL,
		httpClient: client,
	}
}

// Clean 执行账单清洗（使用文件上传方式）
func (c *Cleaner) Clean(inputPath, outputPath string, opts *adapter.CleanOptions) (*adapter.CleanResult, error) {
	// 打开输入文件
	file, err := os.Open(inputPath)
	if err != nil {
		return nil, fmt.Errorf("打开文件失败: %w", err)
	}
	defer file.Close()

	// 创建 multipart form
	var body bytes.Buffer
	writer := multipart.NewWriter(&body)

	// 添加文件
	part, err := writer.CreateFormFile("file", filepath.Base(inputPath))
	if err != nil {
		return nil, fmt.Errorf("创建表单文件失败: %w", err)
	}
	if _, err := io.Copy(part, file); err != nil {
		return nil, fmt.Errorf("复制文件内容失败: %w", err)
	}

	// 添加其他参数
	if opts != nil {
		if opts.Year != "" {
			writer.WriteField("year", opts.Year)
		}
		if opts.Month != "" {
			writer.WriteField("month", opts.Month)
		}
		if opts.Start != "" {
			writer.WriteField("start", opts.Start)
		}
		if opts.End != "" {
			writer.WriteField("end", opts.End)
		}
		if opts.Format != "" {
			writer.WriteField("format", opts.Format)
		}
	}
	writer.WriteField("bill_type", "auto")
	writer.Close()

	// 发送上传请求
	fmt.Printf("🌐 调用清洗服务: %s/clean/upload\n", c.baseURL)
	req, err := http.NewRequest("POST", c.baseURL+"/clean/upload", &body)
	if err != nil {
		return nil, fmt.Errorf("创建请求失败: %w", err)
	}
	req.Header.Set("Content-Type", writer.FormDataContentType())

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("HTTP 请求失败: %w", err)
	}
	defer resp.Body.Close()

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

	// 处理错误响应
	if resp.StatusCode != http.StatusOK {
		var errResp ErrorResponse
		if err := json.Unmarshal(respBody, &errResp); err == nil {
			return nil, fmt.Errorf("清洗失败: %s", errResp.Detail)
		}
		return nil, fmt.Errorf("清洗失败: HTTP %d - %s", resp.StatusCode, string(respBody))
	}

	// 解析成功响应
	var cleanResp CleanResponse
	if err := json.Unmarshal(respBody, &cleanResp); err != nil {
		return nil, fmt.Errorf("解析响应失败: %w", err)
	}

	// 下载清洗后的文件
	if cleanResp.OutputPath != "" {
		if err := c.downloadFile(cleanResp.OutputPath, outputPath); err != nil {
			return nil, fmt.Errorf("下载清洗结果失败: %w", err)
		}
	}

	return &adapter.CleanResult{
		BillType: cleanResp.BillType,
		Output:   cleanResp.Message,
	}, nil
}

// downloadFile 下载清洗后的文件
func (c *Cleaner) downloadFile(remotePath, localPath string) error {
	// 构建下载 URL
	downloadURL := fmt.Sprintf("%s/clean/download/%s", c.baseURL, remotePath)

	resp, err := c.httpClient.Get(downloadURL)
	if err != nil {
		return fmt.Errorf("下载请求失败: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("下载失败: HTTP %d", resp.StatusCode)
	}

	// 创建本地文件
	out, err := os.Create(localPath)
	if err != nil {
		return fmt.Errorf("创建文件失败: %w", err)
	}
	defer out.Close()

	// 写入文件内容
	if _, err := io.Copy(out, resp.Body); err != nil {
		return fmt.Errorf("写入文件失败: %w", err)
	}

	return nil
}

// HealthCheck 检查 Python 服务健康状态
func (c *Cleaner) HealthCheck() error {
	resp, err := c.httpClient.Get(c.baseURL + "/health")
	if err != nil {
		return fmt.Errorf("健康检查失败: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("服务不健康: HTTP %d", resp.StatusCode)
	}

	return nil
}

// 确保 Cleaner 实现了 adapter.Cleaner 接口
var _ adapter.Cleaner = (*Cleaner)(nil)