package app

import (
	"fmt"
	"net"
	"net/http"
	"strings"

	"github.com/go-sql-driver/mysql"
	"github.com/taosdata/driver-go/v3/taosRestful"

	"lingniu/vehicle-data-platform/apps/api/internal/config"
)

// ValidateLocalIsolation runs before constructing any database, external client,
// scheduler or listener. It is an opt-in development boundary, not an auth bypass.
func validOneOSDevBaseURL(value string) bool {
	return value == "https://dev-oneos.lnh2e.com/prod-api" || value == "https://dev-oneos.lnh2e.com/prod-api/" || value == "https://lnoneos.com/prod-api" || value == "https://lnoneos.com/prod-api/"
}

func ValidateLocalIsolation(cfg config.Config) error {
	if err := validateOneOSDevDataProxy(cfg); err != nil {
		return err
	}
	if cfg.OneOSLocalOnly && cfg.OneOSDevIntegration {
		return fmt.Errorf("ONEOS_LOCAL_ONLY and ONEOS_DEV_INTEGRATION are mutually exclusive")
	}
	if cfg.OneOSLocalBackend && !cfg.OneOSDevIntegration {
		return fmt.Errorf("local backend requires dev integration")
	}
	if !cfg.OneOSLocalOnly && !cfg.OneOSDevIntegration {
		return nil
	}
	if cfg.OneOSDevIntegration {
		if !validOneOSDevBaseURL(cfg.OneOSProfileBaseURL) {
			return fmt.Errorf("ONEOS_DEV_INTEGRATION requires an explicitly allowed OneOS HTTPS origin")
		}
		if !validOneOSOrigin(cfg.OneOSPublicOrigin, true) {
			return fmt.Errorf("ONEOS_DEV_INTEGRATION requires a literal loopback public origin")
		}
	}
	host, _, err := net.SplitHostPort(cfg.HTTPAddr)
	if err != nil || net.ParseIP(host) == nil || !net.ParseIP(host).IsLoopback() {
		return fmt.Errorf("local OneOS testing requires an explicit loopback HTTP_ADDR")
	}
	if cfg.OneOSLocalBackend {
		if !cfg.OneOSDevIntegration || cfg.OneOSLocalOnly || !cfg.OneOSAuthEnabled || !cfg.OneOSVehicleQueryScope || cfg.DataMode != "production" || cfg.AuthMode != "enforce" || cfg.OneOSDevDataProxyURL != "" {
			return fmt.Errorf("local backend requires dev OneOS, vehicle-query scope, production store and enforced authentication")
		}
		db, err := mysql.ParseDSN(cfg.MySQLDSN)
		if err != nil || db.Net != "tcp" || !loopbackAddress(db.Addr) {
			return fmt.Errorf("local backend requires a loopback MySQL tunnel")
		}
		if cfg.RedisAddr != "" && !loopbackAddress(cfg.RedisAddr) {
			return fmt.Errorf("local backend requires a loopback Redis tunnel")
		}
		if cfg.TDengineDSN != "" {
			if cfg.TDengineDriver == "taosRestful" {
				rest, err := taosRestful.ParseDSN(cfg.TDengineDSN)
				if err != nil || rest.Net != "http" || rest.Port < 1 || rest.Port > 65535 || !loopbackAddress(net.JoinHostPort(rest.Addr, fmt.Sprint(rest.Port))) {
					return fmt.Errorf("local backend requires a loopback TDengine REST tunnel")
				}
			} else {
				if cfg.TDengineDriver != "" && cfg.TDengineDriver != "taosWS" {
					return fmt.Errorf("local backend requires a supported TDengine driver")
				}
				marker := strings.LastIndex(cfg.TDengineDSN, "@ws(")
				if marker < 0 {
					return fmt.Errorf("local backend requires a TDengine websocket tunnel")
				}
				address := strings.SplitN(cfg.TDengineDSN[marker+4:], ")", 2)
				if len(address) != 2 || !loopbackAddress(address[0]) {
					return fmt.Errorf("local backend requires a loopback TDengine tunnel")
				}
			}
		}
		if cfg.DailyGeographyEnabled || cfg.HistoryCleanupAutomation || cfg.OneOSSSOEnabled || cfg.CapacityCheckBin != "" || cfg.AlertStreamMode != "disabled" || len(cfg.AlertStreamKafkaBrokers) != 0 || cfg.AlertNotificationSMSURL != "" || cfg.AlertNotificationEmailURL != "" || cfg.AlertNotificationWeComURL != "" {
			return fmt.Errorf("local backend must not start production workers or notification delivery")
		}
		return nil
	}
	if cfg.DataMode != "mock" || cfg.AuthMode != "enforce" {
		return fmt.Errorf("local OneOS testing requires DATA_MODE=mock and AUTH_MODE=enforce")
	}
	values := []string{
		cfg.MySQLDSN, cfg.RedisAddr, cfg.TDengineDSN, cfg.CapacityCheckBin,
		cfg.AMapAPIKey, cfg.AMapSecurityCode,
		cfg.AuthToken, cfg.AuthTokensJSON, cfg.BootstrapAdminPassword,
		cfg.AlertNotificationSMSURL, cfg.AlertNotificationEmailURL, cfg.AlertNotificationWeComURL,
		cfg.OneOSIntrospectionURL,
	}
	if cfg.OneOSDevDataProxyURL == "" && (cfg.AMapWebJSKey != "" || cfg.AMapServiceHost != "") {
		return fmt.Errorf("isolated OneOS testing rejects external map configuration")
	}
	if cfg.OneOSDevDataProxyURL != "" && cfg.AMapServiceHost != "" && cfg.AMapServiceHost != "/_AMapService" {
		return fmt.Errorf("real-data development requires the local map proxy path")
	}
	for _, value := range values {
		if strings.TrimSpace(value) != "" {
			return fmt.Errorf("local OneOS testing rejects external data, legacy auth and notification configuration")
		}
	}
	if cfg.DailyGeographyEnabled || cfg.HistoryCleanupAutomation || cfg.OneOSSSOEnabled ||
		(cfg.AlertStreamMode != "" && cfg.AlertStreamMode != "disabled") || len(cfg.AlertStreamKafkaBrokers) != 0 {
		return fmt.Errorf("local OneOS testing rejects external workers and legacy SSO")
	}
	return nil
}

func loopbackAddress(address string) bool {
	host, _, err := net.SplitHostPort(address)
	ip := net.ParseIP(host)
	return err == nil && ip != nil && ip.IsLoopback()
}

func withOneOSLocalIsolationHeaders(next http.Handler, realData ...bool) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// The local UI must not load map SDKs, analytics, APIs or images remotely.
		// Existing index.html contains an inline boot/error indicator. Inline code
		// remains local; every external resource and connection is still excluded.
		w.Header().Set("Content-Security-Policy", "default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob:; font-src 'self' data:; connect-src 'self'; worker-src 'self' blob:; frame-src 'none'; object-src 'none'; base-uri 'self'; form-action 'self'; frame-ancestors 'none'")
		if len(realData) > 0 && realData[0] {
			w.Header().Set("Content-Security-Policy", "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval' https://webapi.amap.com https://jsapi-service.amap.com; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob: https://*.amap.com https://*.autonavi.com; font-src 'self' data:; connect-src 'self' https://*.amap.com https://*.autonavi.com; worker-src 'self' blob:; frame-src 'none'; object-src 'none'; base-uri 'self'; form-action 'self'; frame-ancestors 'none'")
		}
		w.Header().Set("Referrer-Policy", "no-referrer")
		w.Header().Set("X-Content-Type-Options", "nosniff")
		next.ServeHTTP(w, r)
	})
}