package fadada

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"time"
)

// debug 日志：将每次法大大 OpenAPI 调用的 cURL 命令 + 响应落盘到 logs/fadada/<date>/fadada.log
// 用于排查 /sign-task/create-with-template 等接口的实际请求/响应（如免验证签不生效）。
// 敏感字段（AppSecret）不会出现在日志里；AccessToken / Sign 会以明文写入以便复现。

const (
	debugLogDir   = "logs/fadada"
	debugLogFile  = "fadada.log"
	debugMaxBytes = 10 * 1024 * 1024 // 单文件 10MB 后截断覆盖（轮转保持简单）
)

var (
	debugLogMu      sync.Mutex
	debugLogFilePtr *os.File
	debugLogDate    string
	debugLogSize    int64
)

// writeDebugLog 把一次 API 调用的请求与响应追加到当日日志文件。
// 调用方需保证 headers / body / respBody 不包含 AppSecret（法大大签名里只有时间戳参与，secret 本身不出现在 header/body 中）。
func writeDebugLog(method, fullURL string, headers map[string]string, body string, httpStatus int, respBody string, requestID string) {
	if strings.TrimSpace(fullURL) == "" {
		return
	}

	entry := buildDebugEntry(method, fullURL, headers, body, httpStatus, respBody, requestID)

	debugLogMu.Lock()
	defer debugLogMu.Unlock()

	if err := openDebugLogFileLocked(); err != nil {
		// 日志失败不影响业务
		return
	}

	n, _ := debugLogFilePtr.WriteString(entry)
	debugLogSize += int64(n)
	if debugLogSize >= debugMaxBytes {
		_ = debugLogFilePtr.Close()
		debugLogFilePtr = nil
		debugLogSize = 0
	}
}

func openDebugLogFileLocked() error {
	today := time.Now().Format("2006-01-02")
	if debugLogFilePtr != nil && debugLogDate == today {
		return nil
	}
	if debugLogFilePtr != nil {
		_ = debugLogFilePtr.Close()
	}
	dateDir := filepath.Join(debugLogDir, today)
	if err := os.MkdirAll(dateDir, 0o755); err != nil {
		return err
	}
	full := filepath.Join(dateDir, debugLogFile)
	f, err := os.OpenFile(full, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0o644)
	if err != nil {
		return err
	}
	if info, err := f.Stat(); err == nil {
		debugLogSize = info.Size()
	} else {
		debugLogSize = 0
	}
	debugLogFilePtr = f
	debugLogDate = today
	return nil
}

// buildDebugEntry 生成一段可读的日志条目（cURL 命令 + 响应）。
func buildDebugEntry(method, fullURL string, headers map[string]string, body string, httpStatus int, respBody string, requestID string) string {
	now := time.Now().Format("2006-01-02 15:04:05.000")

	var sb strings.Builder
	sb.WriteString("\n==================== ")
	sb.WriteString(now)
	sb.WriteString(" ====================\n")

	// ---- cURL ----
	sb.WriteString("curl -sS -X ")
	sb.WriteString(strings.ToUpper(strings.TrimSpace(method)))
	sb.WriteString(" '")
	sb.WriteString(fullURL)
	sb.WriteString("'")
	for _, k := range sortedHeaderKeys(headers) {
		sb.WriteString(" \\\n  -H '")
		sb.WriteString(k)
		sb.WriteString(": ")
		sb.WriteString(headers[k])
		sb.WriteString("'")
	}
	if strings.TrimSpace(body) != "" {
		sb.WriteString(" \\\n  --data-urlencode 'bizContent=")
		sb.WriteString(body)
		sb.WriteString("'")
	}
	sb.WriteString("\n")

	// ---- RESPONSE ----
	sb.WriteString("--- RESPONSE ---\n")
	sb.WriteString("HTTP ")
	sb.WriteString(fmt.Sprintf("%d", httpStatus))
	if requestID != "" {
		sb.WriteString("  requestId=")
		sb.WriteString(requestID)
	}
	sb.WriteString("\n")
	sb.WriteString("body: ")
	sb.WriteString(respBody)
	sb.WriteString("\n")
	return sb.String()
}

func sortedHeaderKeys(headers map[string]string) []string {
	keys := make([]string, 0, len(headers))
	for k := range headers {
		keys = append(keys, k)
	}
	// 简单冒泡，依赖少
	for i := 0; i < len(keys); i++ {
		for j := i + 1; j < len(keys); j++ {
			if keys[i] > keys[j] {
				keys[i], keys[j] = keys[j], keys[i]
			}
		}
	}
	return keys
}