package api

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

	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/data"
	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/errors"
	s3middleware "git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/middleware"
	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/internal/logs"
	"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/metrics"
	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"
	"go.uber.org/zap"
)

type (
	// Handler is an S3 API handler interface.
	Handler interface {
		HeadObjectHandler(http.ResponseWriter, *http.Request)
		GetObjectACLHandler(http.ResponseWriter, *http.Request)
		PutObjectACLHandler(http.ResponseWriter, *http.Request)
		GetObjectTaggingHandler(http.ResponseWriter, *http.Request)
		PutObjectTaggingHandler(http.ResponseWriter, *http.Request)
		DeleteObjectTaggingHandler(http.ResponseWriter, *http.Request)
		SelectObjectContentHandler(http.ResponseWriter, *http.Request)
		GetObjectRetentionHandler(http.ResponseWriter, *http.Request)
		GetObjectLegalHoldHandler(http.ResponseWriter, *http.Request)
		GetObjectHandler(http.ResponseWriter, *http.Request)
		GetObjectAttributesHandler(http.ResponseWriter, *http.Request)
		CopyObjectHandler(http.ResponseWriter, *http.Request)
		PutObjectRetentionHandler(http.ResponseWriter, *http.Request)
		PutObjectLegalHoldHandler(http.ResponseWriter, *http.Request)
		PutObjectHandler(http.ResponseWriter, *http.Request)
		DeleteObjectHandler(http.ResponseWriter, *http.Request)
		GetBucketLocationHandler(http.ResponseWriter, *http.Request)
		GetBucketPolicyHandler(http.ResponseWriter, *http.Request)
		GetBucketLifecycleHandler(http.ResponseWriter, *http.Request)
		GetBucketEncryptionHandler(http.ResponseWriter, *http.Request)
		GetBucketACLHandler(http.ResponseWriter, *http.Request)
		PutBucketACLHandler(http.ResponseWriter, *http.Request)
		GetBucketCorsHandler(http.ResponseWriter, *http.Request)
		PutBucketCorsHandler(http.ResponseWriter, *http.Request)
		DeleteBucketCorsHandler(http.ResponseWriter, *http.Request)
		GetBucketWebsiteHandler(http.ResponseWriter, *http.Request)
		GetBucketAccelerateHandler(http.ResponseWriter, *http.Request)
		GetBucketRequestPaymentHandler(http.ResponseWriter, *http.Request)
		GetBucketLoggingHandler(http.ResponseWriter, *http.Request)
		GetBucketReplicationHandler(http.ResponseWriter, *http.Request)
		GetBucketTaggingHandler(http.ResponseWriter, *http.Request)
		DeleteBucketWebsiteHandler(http.ResponseWriter, *http.Request)
		DeleteBucketTaggingHandler(http.ResponseWriter, *http.Request)
		GetBucketObjectLockConfigHandler(http.ResponseWriter, *http.Request)
		GetBucketVersioningHandler(http.ResponseWriter, *http.Request)
		GetBucketNotificationHandler(http.ResponseWriter, *http.Request)
		ListenBucketNotificationHandler(http.ResponseWriter, *http.Request)
		ListObjectsV2MHandler(http.ResponseWriter, *http.Request)
		ListObjectsV2Handler(http.ResponseWriter, *http.Request)
		ListBucketObjectVersionsHandler(http.ResponseWriter, *http.Request)
		ListObjectsV1Handler(http.ResponseWriter, *http.Request)
		PutBucketLifecycleHandler(http.ResponseWriter, *http.Request)
		PutBucketEncryptionHandler(http.ResponseWriter, *http.Request)
		PutBucketPolicyHandler(http.ResponseWriter, *http.Request)
		PutBucketObjectLockConfigHandler(http.ResponseWriter, *http.Request)
		PutBucketTaggingHandler(http.ResponseWriter, *http.Request)
		PutBucketVersioningHandler(http.ResponseWriter, *http.Request)
		PutBucketNotificationHandler(http.ResponseWriter, *http.Request)
		CreateBucketHandler(http.ResponseWriter, *http.Request)
		HeadBucketHandler(http.ResponseWriter, *http.Request)
		PostObject(http.ResponseWriter, *http.Request)
		DeleteMultipleObjectsHandler(http.ResponseWriter, *http.Request)
		DeleteBucketPolicyHandler(http.ResponseWriter, *http.Request)
		DeleteBucketLifecycleHandler(http.ResponseWriter, *http.Request)
		DeleteBucketEncryptionHandler(http.ResponseWriter, *http.Request)
		DeleteBucketHandler(http.ResponseWriter, *http.Request)
		ListBucketsHandler(http.ResponseWriter, *http.Request)
		Preflight(w http.ResponseWriter, r *http.Request)
		AppendCORSHeaders(w http.ResponseWriter, r *http.Request)
		CreateMultipartUploadHandler(http.ResponseWriter, *http.Request)
		UploadPartHandler(http.ResponseWriter, *http.Request)
		UploadPartCopy(w http.ResponseWriter, r *http.Request)
		CompleteMultipartUploadHandler(http.ResponseWriter, *http.Request)
		AbortMultipartUploadHandler(http.ResponseWriter, *http.Request)
		ListPartsHandler(w http.ResponseWriter, r *http.Request)
		ListMultipartUploadsHandler(http.ResponseWriter, *http.Request)

		ResolveBucket(ctx context.Context, bucket string) (*data.BucketInfo, error)
	}
)

type Settings interface {
	s3middleware.RequestSettings
	s3middleware.PolicySettings
	s3middleware.MetricsSettings
}

type Config struct {
	Throttle middleware.ThrottleOpts
	Handler  Handler
	Center   s3middleware.Center
	Log      *zap.Logger
	Metrics  *metrics.AppMetrics

	MiddlewareSettings Settings

	// Domains optional. If empty no virtual hosted domains will be attached.
	Domains []string

	// FrostfsID optional. If nil middleware.FrostfsIDValidation won't be attached.
	FrostfsID s3middleware.FrostFSID

	PolicyStorage engine.LocalOverrideEngine
}

func NewRouter(cfg Config) *chi.Mux {
	api := chi.NewRouter()
	api.Use(
		s3middleware.Request(cfg.Log, cfg.MiddlewareSettings),
		middleware.ThrottleWithOpts(cfg.Throttle),
		middleware.Recoverer,
		s3middleware.Tracing(),
		s3middleware.Metrics(cfg.Log, cfg.Handler.ResolveBucket, cfg.Metrics, cfg.MiddlewareSettings),
		s3middleware.LogSuccessResponse(cfg.Log),
		s3middleware.Auth(cfg.Center, cfg.Log),
	)

	if cfg.FrostfsID != nil {
		api.Use(s3middleware.FrostfsIDValidation(cfg.FrostfsID, cfg.Log))
	}

	if cfg.PolicyStorage != nil {
		api.Use(s3middleware.PolicyCheck(cfg.PolicyStorage, cfg.MiddlewareSettings, cfg.Domains, cfg.Log))
	}

	defaultRouter := chi.NewRouter()
	defaultRouter.Mount(fmt.Sprintf("/{%s}", s3middleware.BucketURLPrm), bucketRouter(cfg.Handler, cfg.Log))
	defaultRouter.Get("/", named("ListBuckets", cfg.Handler.ListBucketsHandler))

	hr := NewHostBucketRouter("bucket")
	hr.Default(defaultRouter)
	for _, domain := range cfg.Domains {
		hr.Map(domain, bucketRouter(cfg.Handler, cfg.Log))
	}
	api.Mount("/", hr)

	attachErrorHandler(api)

	return api
}

func named(name string, handlerFunc http.HandlerFunc) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		reqInfo := s3middleware.GetReqInfo(r.Context())
		reqInfo.API = name
		handlerFunc.ServeHTTP(w, r)
	}
}

// If none of the http routes match respond with appropriate errors.
func errorResponseHandler(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()
	reqInfo := s3middleware.GetReqInfo(ctx)

	desc := fmt.Sprintf("Unknown API request at %s", r.URL.Path)
	s3middleware.WriteErrorResponse(w, reqInfo, errors.Error{
		Code:           "UnknownAPIRequest",
		Description:    desc,
		HTTPStatusCode: http.StatusBadRequest,
	})

	if log := s3middleware.GetReqLog(ctx); log != nil {
		log.Error(logs.RequestUnmatched, zap.String("method", reqInfo.API))
	}
}

// attachErrorHandler set NotFoundHandler and MethodNotAllowedHandler for chi.Router.
func attachErrorHandler(api *chi.Mux) {
	errorHandler := http.HandlerFunc(errorResponseHandler)

	// If none of the routes match, add default error handler routes
	api.NotFound(named("NotFound", errorHandler))
	api.MethodNotAllowed(named("MethodNotAllowed", errorHandler))
}

func bucketRouter(h Handler, log *zap.Logger) chi.Router {
	bktRouter := chi.NewRouter()
	bktRouter.Use(
		s3middleware.AddBucketName(log),
		s3middleware.WrapHandler(h.AppendCORSHeaders),
	)

	bktRouter.Mount("/", objectRouter(h, log))

	bktRouter.Options("/", h.Preflight)

	bktRouter.Head("/", named("HeadBucket", h.HeadBucketHandler))

	// GET method handlers
	bktRouter.Group(func(r chi.Router) {
		r.Method(http.MethodGet, "/", NewHandlerFilter().
			Add(NewFilter().
				Queries("uploads").
				Handler(named("ListMultipartUploads", h.ListMultipartUploadsHandler))).
			Add(NewFilter().
				Queries("location").
				Handler(named("GetBucketLocation", h.GetBucketLocationHandler))).
			Add(NewFilter().
				Queries("policy").
				Handler(named("GetBucketPolicy", h.GetBucketPolicyHandler))).
			Add(NewFilter().
				Queries("lifecycle").
				Handler(named("GetBucketLifecycle", h.GetBucketLifecycleHandler))).
			Add(NewFilter().
				Queries("encryption").
				Handler(named("GetBucketEncryption", h.GetBucketEncryptionHandler))).
			Add(NewFilter().
				Queries("cors").
				Handler(named("GetBucketCors", h.GetBucketCorsHandler))).
			Add(NewFilter().
				Queries("acl").
				Handler(named("GetBucketACL", h.GetBucketACLHandler))).
			Add(NewFilter().
				Queries("website").
				Handler(named("GetBucketWebsite", h.GetBucketWebsiteHandler))).
			Add(NewFilter().
				Queries("accelerate").
				Handler(named("GetBucketAccelerate", h.GetBucketAccelerateHandler))).
			Add(NewFilter().
				Queries("requestPayment").
				Handler(named("GetBucketRequestPayment", h.GetBucketRequestPaymentHandler))).
			Add(NewFilter().
				Queries("logging").
				Handler(named("GetBucketLogging", h.GetBucketLoggingHandler))).
			Add(NewFilter().
				Queries("replication").
				Handler(named("GetBucketReplication", h.GetBucketReplicationHandler))).
			Add(NewFilter().
				Queries("tagging").
				Handler(named("GetBucketTagging", h.GetBucketTaggingHandler))).
			Add(NewFilter().
				Queries("object-lock").
				Handler(named("GetBucketObjectLockConfig", h.GetBucketObjectLockConfigHandler))).
			Add(NewFilter().
				Queries("versioning").
				Handler(named("GetBucketVersioning", h.GetBucketVersioningHandler))).
			Add(NewFilter().
				Queries("notification").
				Handler(named("GetBucketNotification", h.GetBucketNotificationHandler))).
			Add(NewFilter().
				Queries("events").
				Handler(named("ListenBucketNotification", h.ListenBucketNotificationHandler))).
			Add(NewFilter().
				QueriesMatch("list-type", "2", "metadata", "true").
				Handler(named("ListObjectsV2M", h.ListObjectsV2MHandler))).
			Add(NewFilter().
				QueriesMatch("list-type", "2").
				Handler(named("ListObjectsV2", h.ListObjectsV2Handler))).
			Add(NewFilter().
				Queries("versions").
				Handler(named("ListBucketObjectVersions", h.ListBucketObjectVersionsHandler))).
			DefaultHandler(named("ListObjectsV1", h.ListObjectsV1Handler)))
	})

	// PUT method handlers
	bktRouter.Group(func(r chi.Router) {
		r.Method(http.MethodPut, "/", NewHandlerFilter().
			Add(NewFilter().
				Queries("cors").
				Handler(named("PutBucketCors", h.PutBucketCorsHandler))).
			Add(NewFilter().
				Queries("acl").
				Handler(named("PutBucketACL", h.PutBucketACLHandler))).
			Add(NewFilter().
				Queries("lifecycle").
				Handler(named("PutBucketLifecycle", h.PutBucketLifecycleHandler))).
			Add(NewFilter().
				Queries("encryption").
				Handler(named("PutBucketEncryption", h.PutBucketEncryptionHandler))).
			Add(NewFilter().
				Queries("policy").
				Handler(named("PutBucketPolicy", h.PutBucketPolicyHandler))).
			Add(NewFilter().
				Queries("object-lock").
				Handler(named("PutBucketObjectLockConfig", h.PutBucketObjectLockConfigHandler))).
			Add(NewFilter().
				Queries("tagging").
				Handler(named("PutBucketTagging", h.PutBucketTaggingHandler))).
			Add(NewFilter().
				Queries("versioning").
				Handler(named("PutBucketVersioning", h.PutBucketVersioningHandler))).
			Add(NewFilter().
				Queries("notification").
				Handler(named("PutBucketNotification", h.PutBucketNotificationHandler))).
			DefaultHandler(named("CreateBucket", h.CreateBucketHandler)))
	})

	// POST method handlers
	bktRouter.Group(func(r chi.Router) {
		r.Method(http.MethodPost, "/", NewHandlerFilter().
			Add(NewFilter().
				Queries("delete").
				Handler(named("DeleteMultipleObjects", h.DeleteMultipleObjectsHandler))).
			// todo consider add filter to match header for defaultHandler:  hdrContentType, "multipart/form-data*"
			DefaultHandler(named("PostObject", h.PostObject)))
	})

	// DELETE method handlers
	bktRouter.Group(func(r chi.Router) {
		r.Method(http.MethodDelete, "/", NewHandlerFilter().
			Add(NewFilter().
				Queries("cors").
				Handler(named("DeleteBucketCors", h.DeleteBucketCorsHandler))).
			Add(NewFilter().
				Queries("website").
				Handler(named("DeleteBucketWebsite", h.DeleteBucketWebsiteHandler))).
			Add(NewFilter().
				Queries("tagging").
				Handler(named("DeleteBucketTagging", h.DeleteBucketTaggingHandler))).
			Add(NewFilter().
				Queries("policy").
				Handler(named("PutBucketPolicy", h.PutBucketPolicyHandler))).
			Add(NewFilter().
				Queries("lifecycle").
				Handler(named("PutBucketLifecycle", h.PutBucketLifecycleHandler))).
			Add(NewFilter().
				Queries("encryption").
				Handler(named("DeleteBucketEncryption", h.DeleteBucketEncryptionHandler))).
			DefaultHandler(named("DeleteBucket", h.DeleteBucketHandler)))
	})

	attachErrorHandler(bktRouter)

	return bktRouter
}

func objectRouter(h Handler, l *zap.Logger) chi.Router {
	objRouter := chi.NewRouter()
	objRouter.Use(s3middleware.AddObjectName(l))

	objRouter.Head("/*", named("HeadObject", h.HeadObjectHandler))

	// GET method handlers
	objRouter.Group(func(r chi.Router) {
		r.Method(http.MethodGet, "/*", NewHandlerFilter().
			Add(NewFilter().
				Queries("uploadId").
				Handler(named("ListParts", h.ListPartsHandler))).
			Add(NewFilter().
				Queries("acl").
				Handler(named("GetObjectACL", h.GetObjectACLHandler))).
			Add(NewFilter().
				Queries("tagging").
				Handler(named("GetObjectTagging", h.GetObjectTaggingHandler))).
			Add(NewFilter().
				Queries("retention").
				Handler(named("GetObjectRetention", h.GetObjectRetentionHandler))).
			Add(NewFilter().
				Queries("legal-hold").
				Handler(named("GetObjectLegalHold", h.GetObjectLegalHoldHandler))).
			Add(NewFilter().
				Queries("attributes").
				Handler(named("GetObjectAttributes", h.GetObjectAttributesHandler))).
			DefaultHandler(named("GetObject", h.GetObjectHandler)))
	})

	// PUT method handlers
	objRouter.Group(func(r chi.Router) {
		r.Method(http.MethodPut, "/*", NewHandlerFilter().
			Add(NewFilter().
				Headers(AmzCopySource).
				Queries("partNumber", "uploadId").
				Handler(named("UploadPartCopy", h.UploadPartCopy))).
			Add(NewFilter().
				Queries("partNumber", "uploadId").
				Handler(named("UploadPart", h.UploadPartHandler))).
			Add(NewFilter().
				Queries("acl").
				Handler(named("PutObjectACL", h.PutObjectACLHandler))).
			Add(NewFilter().
				Queries("tagging").
				Handler(named("PutObjectTagging", h.PutObjectTaggingHandler))).
			Add(NewFilter().
				Headers(AmzCopySource).
				Handler(named("CopyObject", h.CopyObjectHandler))).
			Add(NewFilter().
				Queries("retention").
				Handler(named("PutObjectRetention", h.PutObjectRetentionHandler))).
			Add(NewFilter().
				Queries("legal-hold").
				Handler(named("PutObjectLegalHold", h.PutObjectLegalHoldHandler))).
			DefaultHandler(named("PutObject", h.PutObjectHandler)))
	})

	// POST method handlers
	objRouter.Group(func(r chi.Router) {
		r.Method(http.MethodPost, "/*", NewHandlerFilter().
			Add(NewFilter().
				Queries("uploadId").
				Handler(named("CompleteMultipartUpload", h.CompleteMultipartUploadHandler))).
			Add(NewFilter().
				Queries("uploads").
				Handler(named("CreateMultipartUpload", h.CreateMultipartUploadHandler))).
			DefaultHandler(named("SelectObjectContent", h.SelectObjectContentHandler)))
	})

	// DELETE method handlers
	objRouter.Group(func(r chi.Router) {
		r.Method(http.MethodDelete, "/*", NewHandlerFilter().
			Add(NewFilter().
				Queries("uploadId").
				Handler(named("AbortMultipartUpload", h.AbortMultipartUploadHandler))).
			Add(NewFilter().
				Queries("tagging").
				Handler(named("DeleteObjectTagging", h.DeleteObjectTaggingHandler))).
			DefaultHandler(named("DeleteObject", h.DeleteObjectHandler)))
	})

	attachErrorHandler(objRouter)

	return objRouter
}