package s3api

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

	"github.com/seaweedfs/seaweedfs/weed/filer"
	"github.com/seaweedfs/seaweedfs/weed/glog"
	"github.com/seaweedfs/seaweedfs/weed/pb/s3_pb"
	"github.com/seaweedfs/seaweedfs/weed/util/grace"

	"github.com/gorilla/mux"
	"github.com/seaweedfs/seaweedfs/weed/pb"
	. "github.com/seaweedfs/seaweedfs/weed/s3api/s3_constants"
	"github.com/seaweedfs/seaweedfs/weed/s3api/s3err"
	"github.com/seaweedfs/seaweedfs/weed/security"
	"github.com/seaweedfs/seaweedfs/weed/util"
	util_http "github.com/seaweedfs/seaweedfs/weed/util/http"
	util_http_client "github.com/seaweedfs/seaweedfs/weed/util/http/client"
	"google.golang.org/grpc"
)

type S3ApiServerOption struct {
	Filer                     pb.ServerAddress
	Port                      int
	Config                    string
	DomainName                string
	AllowedOrigins            []string
	BucketsPath               string
	GrpcDialOption            grpc.DialOption
	AllowEmptyFolder          bool
	AllowDeleteBucketNotEmpty bool
	LocalFilerSocket          string
	DataCenter                string
	FilerGroup                string
}

type S3ApiServer struct {
	s3_pb.UnimplementedSeaweedS3Server
	option         *S3ApiServerOption
	iam            *IdentityAccessManagement
	cb             *CircuitBreaker
	randomClientId int32
	filerGuard     *security.Guard
	client         util_http_client.HTTPClientInterface
	bucketRegistry *BucketRegistry
}

func NewS3ApiServer(router *mux.Router, option *S3ApiServerOption) (s3ApiServer *S3ApiServer, err error) {
	v := util.GetViper()
	signingKey := v.GetString("jwt.filer_signing.key")
	v.SetDefault("jwt.filer_signing.expires_after_seconds", 10)
	expiresAfterSec := v.GetInt("jwt.filer_signing.expires_after_seconds")

	readSigningKey := v.GetString("jwt.filer_signing.read.key")
	v.SetDefault("jwt.filer_signing.read.expires_after_seconds", 60)
	readExpiresAfterSec := v.GetInt("jwt.filer_signing.read.expires_after_seconds")

	v.SetDefault("cors.allowed_origins.values", "*")

	if (option.AllowedOrigins == nil) || (len(option.AllowedOrigins) == 0) {
		allowedOrigins := v.GetString("cors.allowed_origins.values")
		domains := strings.Split(allowedOrigins, ",")
		option.AllowedOrigins = domains
	}

	s3ApiServer = &S3ApiServer{
		option:         option,
		iam:            NewIdentityAccessManagement(option),
		randomClientId: util.RandomInt32(),
		filerGuard:     security.NewGuard([]string{}, signingKey, expiresAfterSec, readSigningKey, readExpiresAfterSec),
		cb:             NewCircuitBreaker(option),
	}
	if option.Config != "" {
		grace.OnReload(func() {
			if err := s3ApiServer.iam.loadS3ApiConfigurationFromFile(option.Config); err != nil {
				glog.Errorf("fail to load config file %s: %v", option.Config, err)
			} else {
				glog.V(0).Infof("Loaded %d identities from config file %s", len(s3ApiServer.iam.identities), option.Config)
			}
		})
	}
	s3ApiServer.bucketRegistry = NewBucketRegistry(s3ApiServer)
	if option.LocalFilerSocket == "" {
		if s3ApiServer.client, err = util_http.NewGlobalHttpClient(); err != nil {
			return nil, err
		}
	} else {
		s3ApiServer.client = &http.Client{
			Transport: &http.Transport{
				DialContext: func(_ context.Context, _, _ string) (net.Conn, error) {
					return net.Dial("unix", option.LocalFilerSocket)
				},
			},
		}
	}

	s3ApiServer.registerRouter(router)

	go s3ApiServer.subscribeMetaEvents("s3", time.Now().UnixNano(), filer.DirectoryEtcRoot, []string{option.BucketsPath})
	return s3ApiServer, nil
}

func (s3a *S3ApiServer) registerRouter(router *mux.Router) {
	// API Router
	apiRouter := router.PathPrefix("/").Subrouter()

	// Readiness Probe
	apiRouter.Methods(http.MethodGet).Path("/status").HandlerFunc(s3a.StatusHandler)
	apiRouter.Methods(http.MethodGet).Path("/healthz").HandlerFunc(s3a.StatusHandler)

	apiRouter.Methods(http.MethodOptions).HandlerFunc(
		func(w http.ResponseWriter, r *http.Request) {
			origin := r.Header.Get("Origin")
			if origin != "" {
				if s3a.option.AllowedOrigins == nil || len(s3a.option.AllowedOrigins) == 0 || s3a.option.AllowedOrigins[0] == "*" {
					origin = "*"
				} else {
					originFound := false
					for _, allowedOrigin := range s3a.option.AllowedOrigins {
						if origin == allowedOrigin {
							originFound = true
						}
					}
					if !originFound {
						writeFailureResponse(w, r, http.StatusForbidden)
						return
					}
				}
			}

			w.Header().Set("Access-Control-Allow-Origin", origin)
			w.Header().Set("Access-Control-Expose-Headers", "*")
			w.Header().Set("Access-Control-Allow-Methods", "*")
			w.Header().Set("Access-Control-Allow-Headers", "*")
			writeSuccessResponseEmpty(w, r)
		})

	var routers []*mux.Router
	if s3a.option.DomainName != "" {
		domainNames := strings.Split(s3a.option.DomainName, ",")
		for _, domainName := range domainNames {
			routers = append(routers, apiRouter.Host(
				fmt.Sprintf("%s.%s:%d", "{bucket:.+}", domainName, s3a.option.Port)).Subrouter())
			routers = append(routers, apiRouter.Host(
				fmt.Sprintf("%s.%s", "{bucket:.+}", domainName)).Subrouter())
		}
	}
	routers = append(routers, apiRouter.PathPrefix("/{bucket}").Subrouter())

	for _, bucket := range routers {

		// each case should follow the next rule:
		// - requesting object with query must precede any other methods
		// - requesting object must precede any methods with buckets
		// - requesting bucket with query must precede raw methods with buckets
		// - requesting bucket must be processed in the end

		// objects with query

		// CopyObjectPart
		bucket.Methods(http.MethodPut).Path("/{object:.+}").HeadersRegexp("X-Amz-Copy-Source", `.*?(\/|%2F).*?`).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.CopyObjectPartHandler, ACTION_WRITE)), "PUT")).Queries("partNumber", "{partNumber:[0-9]+}", "uploadId", "{uploadId:.*}")
		// PutObjectPart
		bucket.Methods(http.MethodPut).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.PutObjectPartHandler, ACTION_WRITE)), "PUT")).Queries("partNumber", "{partNumber:[0-9]+}", "uploadId", "{uploadId:.*}")
		// CompleteMultipartUpload
		bucket.Methods(http.MethodPost).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.CompleteMultipartUploadHandler, ACTION_WRITE)), "POST")).Queries("uploadId", "{uploadId:.*}")
		// NewMultipartUpload
		bucket.Methods(http.MethodPost).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.NewMultipartUploadHandler, ACTION_WRITE)), "POST")).Queries("uploads", "")
		// AbortMultipartUpload
		bucket.Methods(http.MethodDelete).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.AbortMultipartUploadHandler, ACTION_WRITE)), "DELETE")).Queries("uploadId", "{uploadId:.*}")
		// ListObjectParts
		bucket.Methods(http.MethodGet).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.ListObjectPartsHandler, ACTION_READ)), "GET")).Queries("uploadId", "{uploadId:.*}")
		// ListMultipartUploads
		bucket.Methods(http.MethodGet).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.ListMultipartUploadsHandler, ACTION_READ)), "GET")).Queries("uploads", "")

		// GetObjectTagging
		bucket.Methods(http.MethodGet).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.GetObjectTaggingHandler, ACTION_READ)), "GET")).Queries("tagging", "")
		// PutObjectTagging
		bucket.Methods(http.MethodPut).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.PutObjectTaggingHandler, ACTION_TAGGING)), "PUT")).Queries("tagging", "")
		// DeleteObjectTagging
		bucket.Methods(http.MethodDelete).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.DeleteObjectTaggingHandler, ACTION_TAGGING)), "DELETE")).Queries("tagging", "")

		// PutObjectACL
		bucket.Methods(http.MethodPut).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.PutObjectAclHandler, ACTION_WRITE_ACP)), "PUT")).Queries("acl", "")
		// PutObjectRetention
		bucket.Methods(http.MethodPut).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.PutObjectRetentionHandler, ACTION_WRITE)), "PUT")).Queries("retention", "")
		// PutObjectLegalHold
		bucket.Methods(http.MethodPut).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.PutObjectLegalHoldHandler, ACTION_WRITE)), "PUT")).Queries("legal-hold", "")
		// PutObjectLockConfiguration
		bucket.Methods(http.MethodPut).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.PutObjectLockConfigurationHandler, ACTION_WRITE)), "PUT")).Queries("object-lock", "")

		// GetObjectACL
		bucket.Methods(http.MethodGet).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.GetObjectAclHandler, ACTION_READ_ACP)), "GET")).Queries("acl", "")

		// objects with query

		// raw objects

		// HeadObject
		bucket.Methods(http.MethodHead).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.HeadObjectHandler, ACTION_READ)), "GET"))

		// GetObject, but directory listing is not supported
		bucket.Methods(http.MethodGet).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.GetObjectHandler, ACTION_READ)), "GET"))

		// CopyObject
		bucket.Methods(http.MethodPut).Path("/{object:.+}").HeadersRegexp("X-Amz-Copy-Source", ".*?(\\/|%2F).*?").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.CopyObjectHandler, ACTION_WRITE)), "COPY"))
		// PutObject
		bucket.Methods(http.MethodPut).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.PutObjectHandler, ACTION_WRITE)), "PUT"))
		// DeleteObject
		bucket.Methods(http.MethodDelete).Path("/{object:.+}").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.DeleteObjectHandler, ACTION_WRITE)), "DELETE"))

		// raw objects

		// buckets with query

		// DeleteMultipleObjects
		bucket.Methods(http.MethodPost).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.DeleteMultipleObjectsHandler, ACTION_WRITE)), "DELETE")).Queries("delete", "")

		// GetBucketACL
		bucket.Methods(http.MethodGet).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.GetBucketAclHandler, ACTION_READ_ACP)), "GET")).Queries("acl", "")
		// PutBucketACL
		bucket.Methods(http.MethodPut).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.PutBucketAclHandler, ACTION_WRITE_ACP)), "PUT")).Queries("acl", "")

		// GetBucketPolicy
		bucket.Methods(http.MethodGet).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.GetBucketPolicyHandler, ACTION_READ)), "GET")).Queries("policy", "")
		// PutBucketPolicy
		bucket.Methods(http.MethodPut).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.PutBucketPolicyHandler, ACTION_WRITE)), "PUT")).Queries("policy", "")
		// DeleteBucketPolicy
		bucket.Methods(http.MethodDelete).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.DeleteBucketPolicyHandler, ACTION_WRITE)), "DELETE")).Queries("policy", "")

		// GetBucketCors
		bucket.Methods(http.MethodGet).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.GetBucketCorsHandler, ACTION_READ)), "GET")).Queries("cors", "")
		// PutBucketCors
		bucket.Methods(http.MethodPut).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.PutBucketCorsHandler, ACTION_WRITE)), "PUT")).Queries("cors", "")
		// DeleteBucketCors
		bucket.Methods(http.MethodDelete).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.DeleteBucketCorsHandler, ACTION_WRITE)), "DELETE")).Queries("cors", "")

		// GetBucketLifecycleConfiguration
		bucket.Methods(http.MethodGet).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.GetBucketLifecycleConfigurationHandler, ACTION_READ)), "GET")).Queries("lifecycle", "")
		// PutBucketLifecycleConfiguration
		bucket.Methods(http.MethodPut).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.PutBucketLifecycleConfigurationHandler, ACTION_WRITE)), "PUT")).Queries("lifecycle", "")
		// DeleteBucketLifecycleConfiguration
		bucket.Methods(http.MethodDelete).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.DeleteBucketLifecycleHandler, ACTION_WRITE)), "DELETE")).Queries("lifecycle", "")

		// GetBucketLocation
		bucket.Methods(http.MethodGet).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.GetBucketLocationHandler, ACTION_READ)), "GET")).Queries("location", "")

		// GetBucketRequestPayment
		bucket.Methods(http.MethodGet).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.GetBucketRequestPaymentHandler, ACTION_READ)), "GET")).Queries("requestPayment", "")

		// GetBucketVersioning
		bucket.Methods(http.MethodGet).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.GetBucketVersioningHandler, ACTION_READ)), "GET")).Queries("versioning", "")
		bucket.Methods(http.MethodPut).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.PutBucketVersioningHandler, ACTION_WRITE)), "PUT")).Queries("versioning", "")

		// ListObjectsV2
		bucket.Methods(http.MethodGet).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.ListObjectsV2Handler, ACTION_LIST)), "LIST")).Queries("list-type", "2")

		// buckets with query
		// PutBucketOwnershipControls
		bucket.Methods(http.MethodPut).HandlerFunc(track(s3a.iam.Auth(s3a.PutBucketOwnershipControls, ACTION_ADMIN), "PUT")).Queries("ownershipControls", "")

		//GetBucketOwnershipControls
		bucket.Methods(http.MethodGet).HandlerFunc(track(s3a.iam.Auth(s3a.GetBucketOwnershipControls, ACTION_READ), "GET")).Queries("ownershipControls", "")

		//DeleteBucketOwnershipControls
		bucket.Methods(http.MethodDelete).HandlerFunc(track(s3a.iam.Auth(s3a.DeleteBucketOwnershipControls, ACTION_ADMIN), "DELETE")).Queries("ownershipControls", "")

		// raw buckets

		// PostPolicy
		bucket.Methods(http.MethodPost).HeadersRegexp("Content-Type", "multipart/form-data*").HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.PostPolicyBucketHandler, ACTION_WRITE)), "POST"))

		// HeadBucket
		bucket.Methods(http.MethodHead).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.HeadBucketHandler, ACTION_READ)), "GET"))

		// PutBucket
		bucket.Methods(http.MethodPut).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.PutBucketHandler, ACTION_ADMIN)), "PUT"))

		// DeleteBucket
		bucket.Methods(http.MethodDelete).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.DeleteBucketHandler, ACTION_DELETE_BUCKET)), "DELETE"))

		// ListObjectsV1 (Legacy)
		bucket.Methods(http.MethodGet).HandlerFunc(track(s3a.iam.Auth(s3a.cb.Limit(s3a.ListObjectsV1Handler, ACTION_LIST)), "LIST"))

		// raw buckets

	}

	// ListBuckets
	apiRouter.Methods(http.MethodGet).Path("/").HandlerFunc(track(s3a.ListBucketsHandler, "LIST"))

	// NotFound
	apiRouter.NotFoundHandler = http.HandlerFunc(s3err.NotFoundHandler)

}