package http

import (
	"context"
	"log/slog"
	"net/http"
	"strings"
	"time"

	userv1 "hyapp.local/api/proto/user/v1"
	"hyapp/pkg/appcode"
	"hyapp/pkg/logx"
	"hyapp/pkg/xerr"
	"hyapp/services/gateway-service/internal/auth"
)

// apiHandler 包装需要 app 解析和 access token 的业务 API。
func (h *Handler) apiHandler(jwtVerifier *auth.Verifier, next http.HandlerFunc) http.Handler {
	return withRequestID(withAccessLog(h.withResolvedApp(h.withAuth(jwtVerifier, next))))
}

// profileAPIHandler 包装需要 app 解析、access token 和完整资料门禁的业务 API。
func (h *Handler) profileAPIHandler(jwtVerifier *auth.Verifier, next http.HandlerFunc) http.Handler {
	return withRequestID(withAccessLog(h.withResolvedApp(h.withAuth(jwtVerifier, requireCompletedProfile(next)))))
}

// publicAPIHandler 包装只需要 app 解析的公开 API；登录/注册会用解析结果创建对应 App 的用户。
func (h *Handler) publicAPIHandler(next http.HandlerFunc) http.Handler {
	return withRequestID(withAccessLog(h.withResolvedApp(next)))
}

// withAccessLog 统一记录 gateway 业务 API 的请求体、响应体、状态码和耗时。
// healthcheck 不经过该 middleware，避免探活日志淹没业务调用。
func withAccessLog(next http.Handler) http.Handler {
	return logx.HTTPMiddleware("gateway-service", requestIDFromContext, next)
}

// withAuth 在 transport 层完成鉴权失败响应写入。
// auth 包只返回身份校验结果，避免底层鉴权模块绑定 gateway 的 JSON envelope。
func (h *Handler) withAuth(jwtVerifier *auth.Verifier, next http.HandlerFunc) http.Handler {
	return http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
		claims, err := jwtVerifier.Verify(request.Header.Get("Authorization"))
		if err != nil {
			writeError(writer, request, http.StatusUnauthorized, codeUnauthorized, "unauthorized")
			return
		}
		if strings.TrimSpace(claims.SessionID) == "" {
			writeError(writer, request, http.StatusUnauthorized, string(xerr.SessionRevoked), "unauthorized")
			return
		}

		ctx := auth.WithClaims(request.Context(), claims)
		revoked, err := h.revokedSession(ctx, claims.AppCode, claims.SessionID)
		if err != nil {
			logx.Warn(ctx, "session_denylist_read_failed", slog.String("component", "gateway_auth"), slog.String("session_id", claims.SessionID), slog.String("error", err.Error()))
		}
		if revoked {
			writeError(writer, request.WithContext(ctx), http.StatusUnauthorized, string(xerr.SessionRevoked), "unauthorized")
			return
		}
		next.ServeHTTP(writer, request.WithContext(ctx))
	})
}

func (h *Handler) revokedSession(ctx context.Context, appCode string, sessionID string) (bool, error) {
	if h.loginRiskCache == nil {
		return false, nil
	}
	return h.loginRiskCache.RevokedSessionExists(ctx, appCode, sessionID)
}

// withResolvedApp 在入口处把包名或显式 app_code 解析成内部租户键并写入 context。
// 公开接口依赖请求头解析；鉴权接口稍后会由 token claims 再覆盖一次，防止跨 App 串 token。
func (h *Handler) withResolvedApp(next http.Handler) http.Handler {
	return http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
		appCode, err := h.resolveRequestAppCode(request.Context(), request)
		if err != nil {
			writeRPCError(writer, request, err)
			return
		}

		ctx := appcode.WithContext(request.Context(), appCode)
		next.ServeHTTP(writer, request.WithContext(ctx))
	})
}

func (h *Handler) resolveRequestAppCode(ctx context.Context, request *http.Request) (string, error) {
	explicitAppCode := firstHeader(request, "X-App-Code", "X-HY-App-Code", "App-Code")
	packageName := firstHeader(request, "X-App-Package", "X-Package-Name", "X-App-Bundle-ID", "X-Bundle-ID")
	platform := firstHeader(request, "X-App-Platform", "X-Platform")
	if h.appRegistryClient != nil && (explicitAppCode != "" || packageName != "") {
		resp, err := h.appRegistryClient.ResolveApp(ctx, &userv1.ResolveAppRequest{
			Meta: &userv1.RequestMeta{
				RequestId: requestIDFromContext(ctx),
				Caller:    "gateway-service",
				SentAtMs:  time.Now().UnixMilli(),
				AppCode:   explicitAppCode,
			},
			PackageName: packageName,
			Platform:    platform,
			AppCode:     explicitAppCode,
		})
		if err != nil {
			return "", err
		}
		if resp.GetApp() != nil {
			return appcode.Normalize(resp.GetApp().GetAppCode()), nil
		}
	}

	if strings.EqualFold(packageName, "com.org.laluparty") {
		// 开发阶段先保留用户明确给出的包名映射；生产仍以 user-service apps 表为准。
		return "lalu", nil
	}

	return appcode.Normalize(explicitAppCode), nil
}

func firstHeader(request *http.Request, names ...string) string {
	for _, name := range names {
		value := strings.TrimSpace(request.Header.Get(name))
		if value != "" {
			return value
		}
	}

	return ""
}

// requireMethod 在业务 handler 之前固定 HTTP method，避免 path-only mux 让错误 method 进入命令链路。
func requireMethod(method string, next http.HandlerFunc) http.HandlerFunc {
	return func(writer http.ResponseWriter, request *http.Request) {
		if request.Method != method {
			writeError(writer, request, http.StatusMethodNotAllowed, codeInvalidArgument, "invalid argument")
			return
		}

		next(writer, request)
	}
}

// requireCompletedProfile 在 gateway 层执行外部准入门禁。
// 这里故意不访问 user-service，依赖 access token 快照，避免所有高频房间入口同步打用户服务。
func requireCompletedProfile(next http.HandlerFunc) http.HandlerFunc {
	return func(writer http.ResponseWriter, request *http.Request) {
		if !auth.ProfileCompletedFromContext(request.Context()) {
			writeError(writer, request, http.StatusForbidden, codeProfileRequired, "profile required")
			return
		}

		next.ServeHTTP(writer, request)
	}
}