package service

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"

	"github.com/gogf/gf/v2/os/glog"
)

// ============================================
// 文件处理
// ============================================

func fetchFileTexts(ctx context.Context, urls []string) map[string]string {
	result := make(map[string]string)

	if len(urls) == 0 {
		return result
	}

	client := &http.Client{
		Timeout: 8 * time.Second,
	}

	for _, rawURL := range urls {
		url := sanitizeURL(rawURL)
		if url == "" {
			continue
		}

		text, err := fetchFileContent(ctx, client, url)
		if err != nil {
			glog.Warningf(ctx,
				"[FetchFile] failed url=%s err=%v",
				url,
				err,
			)
			continue
		}

		if text == "" {
			continue
		}

		result[url] = text
	}

	return result
}

func fetchFileContent(
	ctx context.Context,
	client *http.Client,
	url string,
) (string, error) {

	req, err := http.NewRequestWithContext(
		ctx,
		http.MethodGet,
		url,
		nil,
	)
	if err != nil {
		return "", err
	}

	resp, err := client.Do(req)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	// HTTP状态检查
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return "", fmt.Errorf("HTTP %d", resp.StatusCode)
	}

	// Content-Type检查
	contentType := strings.ToLower(resp.Header.Get("Content-Type"))

	if !isTextContentType(contentType) {
		return "", fmt.Errorf("unsupported content-type: %s", contentType)
	}

	// 最大读取20KB
	body, err := io.ReadAll(
		io.LimitReader(resp.Body, 20*1024),
	)
	if err != nil {
		return "", err
	}

	return strings.TrimSpace(string(body)), nil
}

// 判断是否为文本类型
func isTextContentType(contentType string) bool {

	// text/*
	if strings.HasPrefix(contentType, "text/") {
		return true
	}

	// 常见文本类型
	allowTypes := []string{
		"application/json",
		"application/xml",
		"application/javascript",
		"application/x-yaml",
		"application/yaml",
		"application/toml",
	}

	for _, t := range allowTypes {
		if strings.Contains(contentType, t) {
			return true
		}
	}

	return false
}

func sanitizeURL(raw string) string {
	s := strings.TrimSpace(raw)
	s = strings.Trim(s, "`\"")
	return s
}