package main

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"io/fs"
	"log/slog"
	"net"
	"net/http"
	"os"
	"os/signal"
	"path/filepath"
	"strconv"
	"strings"
	"syscall"
	"time"

	"github.com/gin-contrib/cors"
	"github.com/gin-gonic/gin"

	"rill/docs"
	"rill/internal/api"
	"rill/internal/config"
	"rill/internal/database"
	"rill/internal/utils"
)

//go:generate go tool swag init -g main.go -o docs --parseInternal

// @title           Rill API
// @version         1.0
// @description     Rill server HTTP API documentation. All endpoints are prefixed with api.prefix (default /api); requests and responses are JSON.
// @description     Swagger UI: {prefix}/swagger/index.html; OpenAPI JSON: {prefix}/swagger/doc.json.
// @description     Endpoints are grouped by required permission: public needs no authentication, user needs a Bearer JWT obtained from /auth/login, admin needs an admin user.
// @BasePath        /api
// @tag.name         public
// @tag.description  No authentication required
// @tag.name         user
// @tag.description  Requires a logged-in user (Bearer JWT)
// @tag.name         admin
// @tag.description  Requires an admin user (Bearer JWT + admin group)
// @securityDefinitions.apikey  BearerAuth
// @in                          header
// @name                        Authorization
// @description                 Bearer JWT, format: Bearer {token}, obtained from /auth/login
func main() {
	configPath := flag.String("c", "data/config.yaml", "配置文件路径（不存在时自动生成）")
	flag.Parse()

	cfg, err := config.LoadConfig(*configPath)
	if err != nil {
		slog.Error("加载配置失败", "err", err)
		os.Exit(1)
	}
	slog.SetDefault(slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{Level: cfg.LogLevel()})))

	// 接口文档路径跟随 API 前缀
	docs.SwaggerInfo.BasePath = cfg.API.Prefix

	//设置gin运行模式
	gin.SetMode(cfg.Server.Mode)

	//启动gin服务
	r := gin.New()
	// 可信代理配置需同时应用于 gin（访问日志 IP）与 utils（业务取 IP）
	if err := r.SetTrustedProxies(cfg.Server.TrustedProxies); err != nil {
		slog.Error("设置 gin 可信代理失败", "err", err)
		os.Exit(1)
	}
	if err := utils.SetTrustedProxies(cfg.Server.TrustedProxies); err != nil {
		slog.Error("设置可信代理失败", "err", err)
		os.Exit(1)
	}
	r.Use(gin.Recovery())
	if cfg.Log.AccessLog {
		r.Use(gin.Logger())
	}
	if cfg.API.CORS.Enabled {
		r.Use(cors.New(cors.Config{
			AllowOrigins:     cfg.API.CORS.AllowOrigins,
			AllowMethods:     cfg.API.CORS.AllowMethods,
			AllowHeaders:     cfg.API.CORS.AllowHeaders,
			AllowCredentials: cfg.API.CORS.AllowCredentials,
			MaxAge:           cfg.CORSMaxAge(),
		}))
	}

	// 初始化数据库并执行迁移
	db, err := database.Open(cfg)
	if err != nil {
		slog.Error("初始化数据库失败", "err", err)
		os.Exit(1)
	}
	defer func() {
		if err := database.Close(db); err != nil {
			slog.Warn("关闭数据库失败", "err", err)
		}
	}()

	migrateCtx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	err = database.Migrate(migrateCtx, db)
	cancel()
	if err != nil {
		slog.Error("数据库迁移失败", "err", err)
		os.Exit(1)
	}

	// API 路由
	api.RegisterRoutes(r.Group(cfg.API.Prefix), db, cfg)

	// 静态文件服务
	fs := http.FileServer(http.Dir(cfg.Static.Dir))
	indexFile := filepath.Join(cfg.Static.Dir, "index.html")
	// 中间件处理路由
	r.Use(func(c *gin.Context) {
		if strings.HasPrefix(c.Request.URL.Path, cfg.API.Prefix) {
			c.Next() // 继续处理API请求
			return
		}

		// 处理静态文件；未命中的无扩展名路径回退到 index.html，支持前端 history 路由
		cleanPath := filepath.Clean(c.Request.URL.Path)
		if _, err := os.Stat(filepath.Join(cfg.Static.Dir, cleanPath)); err != nil && filepath.Ext(cleanPath) == "" {
			c.File(indexFile)
			c.Abort()
			return
		}
		fs.ServeHTTP(c.Writer, c.Request)
		c.Abort()
	})

	if err := serve(cfg, r); err != nil {
		slog.Error("服务运行失败", "err", err)
		os.Exit(1)
	}
}

// serve 依据配置监听 TCP 与 unix socket（可同时启用），并在收到退出信号后优雅关闭。
func serve(cfg *config.Config, handler http.Handler) error {
	srv := &http.Server{Handler: handler}

	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer stop()

	errCh := make(chan error, 2)
	listen := func(network, addr string) error {
		ln, err := net.Listen(network, addr)
		if err != nil {
			return fmt.Errorf("监听 %s %s 失败: %w", network, addr, err)
		}
		slog.Info("服务监听中", "network", network, "addr", addr, "static", cfg.Static.Dir, "mode", cfg.Server.Mode)
		go func() {
			if err := srv.Serve(ln); err != nil && !errors.Is(err, http.ErrServerClosed) {
				errCh <- err
			}
		}()
		return nil
	}

	if cfg.Server.TCPEnabled() {
		addr := net.JoinHostPort(cfg.Server.Host, strconv.Itoa(cfg.Server.Port))
		if err := listen("tcp", addr); err != nil {
			return err
		}
	}
	if cfg.Server.SockEnabled() {
		sock := strings.TrimSpace(cfg.Server.Sock)
		if err := os.Remove(sock); err != nil && !errors.Is(err, fs.ErrNotExist) {
			return fmt.Errorf("清理残留 socket %s 失败: %w", sock, err)
		}
		if err := listen("unix", sock); err != nil {
			return err
		}
		defer os.Remove(sock)
	}

	select {
	case err := <-errCh:
		return err
	case <-ctx.Done():
		stop()
		slog.Info("收到退出信号，正在关闭服务")
		shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
		defer cancel()
		if err := srv.Shutdown(shutdownCtx); err != nil {
			return fmt.Errorf("关闭服务失败: %w", err)
		}
	}
	return nil
}