package api

import (
	"net/http"
	"strings"

	"github.com/gin-gonic/gin"
	"vpn-platform/backend/internal/model"
	"vpn-platform/backend/internal/nginxgateway"
	"vpn-platform/backend/internal/service"
	"vpn-platform/backend/internal/store"
	"vpn-platform/backend/internal/tlsservice"
)

// Only a single OpenVPN WebAuth instance may own /oauth2/ on the management
// hostname. Never route an arbitrary user-supplied address to a local port.
func authGatewayPort(domain string) (int, error) {
	var tunnels []model.Tunnel
	if err := store.DB.Where("protocol = ? AND state = ?", "openvpn", "running").Find(&tunnels).Error; err != nil {
		return 0, err
	}
	port := 0
	for _, tunnel := range tunnels {
		cfg, err := store.TunnelConfig(&tunnel)
		if err != nil {
			return 0, err
		}
		if service.Str(cfg, "auth_mode") != "oidc" || !strings.EqualFold(strings.TrimRight(service.Str(cfg, "oidc_base_url"), "/"), "https://"+domain) {
			continue
		}
		if port != 0 {
			return 0, &gatewayConflict{}
		}
		port = int(service.Num(cfg, "oidc_http_port", 0))
	}
	return port, nil
}

type gatewayConflict struct{}

func (*gatewayConflict) Error() string {
	return "当前域名存在多条运行中的 OIDC 专线，请先保留一条"
}

func (s *Server) identityGateway(c *gin.Context) {
	status := tlsservice.Status()
	if !status.Valid || status.Mode != "nginx" || status.RestartRequired || nginxgateway.Stage() != "https" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "请先完成 Nginx HTTPS 入口配置"})
		return
	}
	port, err := authGatewayPort(status.Domain)
	if err != nil {
		c.JSON(400, gin.H{"error": err.Error()})
		return
	}
	if err := nginxgateway.RefreshAuth(status.Domain, s.router.Routes(), port); err != nil {
		c.JSON(500, gin.H{"error": err.Error()})
		return
	}
	store.Audit(c.GetString("username"), "identity_gateway_updated", status.Domain, "")
	c.JSON(200, gin.H{"ok": true, "identity_route": true, "auth_route": port != 0, "auth_port": port})
}