package yuyuecha

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

const debugExchangeFileName = "dev_curl.log"

var debugExchangeMu sync.Mutex

type debugExchangeRecord struct {
	RequestID     string
	TransactionID string
	API           string
	Status        int
	Duration      time.Duration
	Curl          string
	ResponseBody  []byte
	Error         string
}

// writeDebugExchange 开发环境写入单一排查文件：一次调用一条记录，含 curl + response
func writeDebugExchange(logDir string, rec debugExchangeRecord) {
	if strings.TrimSpace(logDir) == "" || strings.TrimSpace(rec.Curl) == "" {
		return
	}

	var b strings.Builder
	b.WriteString(strings.Repeat("=", 72))
	b.WriteByte('\n')
	b.WriteString("time: ")
	b.WriteString(time.Now().Format("2006-01-02 15:04:05.000"))
	b.WriteByte('\n')
	b.WriteString("request_id: ")
	b.WriteString(rec.RequestID)
	b.WriteByte('\n')
	// 与上游签名头 nonce 一致，对外排查只提供 request_id 即可
	b.WriteString("nonce: ")
	b.WriteString(rec.RequestID)
	b.WriteByte('\n')
	if rec.TransactionID != "" {
		b.WriteString("transaction_id: ")
		b.WriteString(rec.TransactionID)
		b.WriteByte('\n')
	}
	b.WriteString("api: ")
	b.WriteString(rec.API)
	b.WriteByte('\n')
	if rec.Status > 0 {
		b.WriteString(fmt.Sprintf("status: %d\n", rec.Status))
	}
	b.WriteString(fmt.Sprintf("duration: %s\n", rec.Duration.Round(time.Millisecond)))
	if rec.Error != "" {
		b.WriteString("error: ")
		b.WriteString(rec.Error)
		b.WriteByte('\n')
	}

	b.WriteByte('\n')
	b.WriteString("[curl]\n")
	b.WriteString(rec.Curl)
	b.WriteByte('\n')

	b.WriteByte('\n')
	b.WriteString("[response]\n")
	if len(rec.ResponseBody) == 0 {
		b.WriteString("(empty)\n")
	} else {
		b.WriteString(prettyJSONForLog(rec.ResponseBody))
		b.WriteByte('\n')
	}
	b.WriteString(strings.Repeat("=", 72))
	b.WriteString("\n\n")

	debugExchangeMu.Lock()
	defer debugExchangeMu.Unlock()

	if err := os.MkdirAll(logDir, 0755); err != nil {
		return
	}
	path := filepath.Join(logDir, debugExchangeFileName)
	f, err := os.OpenFile(path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		return
	}
	defer f.Close()
	_, _ = f.WriteString(b.String())
}

func prettyJSONForLog(raw []byte) string {
	trimmed := bytes.TrimSpace(raw)
	if len(trimmed) == 0 {
		return "(empty)"
	}
	var buf bytes.Buffer
	if err := json.Indent(&buf, trimmed, "", "  "); err != nil {
		return string(raw)
	}
	return buf.String()
}