package main

import (
	"bytes"
	"crypto/hmac"
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"
)

// GiteaPayload Gitea webhook 推送事件
type GiteaPayload struct {
	Repository struct {
		Name     string `json:"name"`
		FullName string `json:"full_name"`
		CloneURL string `json:"clone_url"`
	} `json:"repository"`
	Pusher struct {
		Username string `json:"username"`
	} `json:"pusher"`
	Ref    string `json:"ref"`
	Commit string `json:"after"`
}

// Config webhook 服务配置
type Config struct {
	Port       string
	Secret     string
	RepoPath   string
	ScriptPath string
}

var cfg Config

func init() {
	// 从环境变量读取配置
	cfg.Port = os.Getenv("WEBHOOK_PORT")
	if cfg.Port == "" {
		cfg.Port = "9000"
	}

	cfg.Secret = os.Getenv("WEBHOOK_SECRET")
	if cfg.Secret == "" {
		cfg.Secret = "your-webhook-secret"
	}

	cfg.RepoPath = os.Getenv("REPO_PATH")
	if cfg.RepoPath == "" {
		cfg.RepoPath = "/app"
	}

	cfg.ScriptPath = filepath.Join(cfg.RepoPath, "deploy.sh")
}

func main() {
	log.SetFlags(log.LstdFlags | log.Lshortfile)
	log.Printf("🚀 Webhook 服务启动 | 监听端口: %s\n", cfg.Port)
	log.Printf("📁 仓库路径: %s\n", cfg.RepoPath)
	log.Printf("📜 部署脚本: %s\n", cfg.ScriptPath)

	http.HandleFunc("/webhook", handleWebhook)
	http.HandleFunc("/health", handleHealth)

	if err := http.ListenAndServe(":"+cfg.Port, nil); err != nil {
		log.Fatalf("❌ 服务器启动失败: %v", err)
	}
}

// handleHealth 健康检查端点
func handleHealth(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(map[string]string{
		"status": "ok",
		"time":   time.Now().Format(time.RFC3339),
	})
}

// handleWebhook 处理 Gitea webhook
func handleWebhook(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	// 读取请求体
	body, err := io.ReadAll(r.Body)
	if err != nil {
		log.Printf("❌ 读取请求体失败: %v", err)
		http.Error(w, "Failed to read body", http.StatusBadRequest)
		return
	}
	defer r.Body.Close()

	// 验证签名
	if !verifySignature(r.Header.Get("X-Gitea-Signature"), body) {
		log.Println("⚠️  无效的签名")
		http.Error(w, "Invalid signature", http.StatusUnauthorized)
		return
	}

	// 解析 payload
	var payload GiteaPayload
	if err := json.Unmarshal(body, &payload); err != nil {
		log.Printf("❌ 解析 JSON 失败: %v", err)
		http.Error(w, "Failed to parse JSON", http.StatusBadRequest)
		return
	}

	// 只处理 master 分支的推送
	if !strings.Contains(payload.Ref, "master") && !strings.Contains(payload.Ref, "main") {
		log.Printf("⏭️  忽略非主分支推送: %s", payload.Ref)
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]string{
			"message": "非主分支，跳过部署",
		})
		return
	}

	log.Printf("✅ 收到有效的 Webhook 请求")
	log.Printf("   仓库: %s", payload.Repository.FullName)
	log.Printf("   推送者: %s", payload.Pusher.Username)
	log.Printf("   分支: %s", payload.Ref)
	commitShort := payload.Commit
	if len(commitShort) > 7 {
		commitShort = commitShort[:7]
	}
	log.Printf("   提交: %s", commitShort)

	// 异步执行部署
	go executeDeployment(payload)

	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusAccepted)
	json.NewEncoder(w).Encode(map[string]string{
		"message": "部署已启动",
		"commit":  payload.Commit,
	})
}

// verifySignature 验证 Gitea webhook 签名
func verifySignature(signature string, body []byte) bool {
	if cfg.Secret == "your-webhook-secret" {
		log.Println("⚠️  警告: 使用默认 secret，建议设置 WEBHOOK_SECRET 环境变量")
		return true
	}

	hash := hmac.New(sha256.New, []byte(cfg.Secret))
	hash.Write(body)
	expected := "sha256=" + hex.EncodeToString(hash.Sum(nil))

	return signature == expected
}

// executeDeployment 执行部署
func executeDeployment(payload GiteaPayload) {
	log.Println("\n🔄 开始部署流程...")

	startTime := time.Now()

	// 检查脚本是否存在
	if _, err := os.Stat(cfg.ScriptPath); os.IsNotExist(err) {
		log.Printf("❌ 部署脚本不存在: %s", cfg.ScriptPath)
		return
	}

	// 执行部署脚本
	cmd := exec.Command("bash", cfg.ScriptPath)
	cmd.Dir = cfg.RepoPath

	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	log.Printf("📜 执行部署脚本: %s", cfg.ScriptPath)

	if err := cmd.Run(); err != nil {
		log.Printf("❌ 部署脚本执行失败: %v", err)
		if stderr.Len() > 0 {
			log.Printf("错误输出:\n%s", stderr.String())
		}
		return
	}

	duration := time.Since(startTime).Seconds()

	log.Printf("✅ 部署完成")
	log.Printf("   耗时: %.2f 秒", duration)

	if stdout.Len() > 0 {
		log.Printf("输出:\n%s", stdout.String())
	}

	log.Printf("📝 部署日志:\n")
	log.Printf("   仓库: %s", payload.Repository.FullName)
	log.Printf("   提交: %s", payload.Commit[:7])
	log.Printf("   分支: %s", payload.Ref)
	log.Printf("   推送者: %s", payload.Pusher.Username)
	log.Printf("   时间: %s", time.Now().Format(time.RFC3339))
}