package weed_server

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

	"github.com/seaweedfs/seaweedfs/weed/s3api/s3_constants"

	"github.com/seaweedfs/seaweedfs/weed/glog"
	"github.com/seaweedfs/seaweedfs/weed/operation"
	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
	"github.com/seaweedfs/seaweedfs/weed/security"
	"github.com/seaweedfs/seaweedfs/weed/stats"
	"github.com/seaweedfs/seaweedfs/weed/storage/needle"
	"github.com/seaweedfs/seaweedfs/weed/util"
	"github.com/seaweedfs/seaweedfs/weed/util/constants"
	util_http "github.com/seaweedfs/seaweedfs/weed/util/http"
)

var (
	OS_UID = uint32(os.Getuid())
	OS_GID = uint32(os.Getgid())

	ErrReadOnly = errors.New("read only")
)

type FilerPostResult struct {
	Name  string `json:"name,omitempty"`
	Size  int64  `json:"size,omitempty"`
	Error string `json:"error,omitempty"`
}

func (fs *FilerServer) assignNewFileInfo(ctx context.Context, so *operation.StorageOption, expectedDataSize uint64) (fileId, urlLocation string, auth security.EncodedJwt, err error) {

	stats.FilerHandlerCounter.WithLabelValues(stats.ChunkAssign).Inc()
	start := time.Now()
	defer func() {
		stats.FilerRequestHistogram.WithLabelValues(stats.ChunkAssign).Observe(time.Since(start).Seconds())
	}()

	ar, altRequest := so.ToAssignRequests(1)
	ar.ExpectedDataSize = expectedDataSize
	if altRequest != nil {
		altRequest.ExpectedDataSize = expectedDataSize
	}

	// Use a context that ignores cancellation from the request context
	assignCtx := context.WithoutCancel(ctx)

	assignResult, ae := operation.Assign(assignCtx, fs.filer.GetMaster, fs.grpcDialOption, ar, altRequest)
	if ae != nil {
		glog.ErrorfCtx(ctx, "failing to assign a file id: %v", ae)
		err = ae
		return
	}
	fileId = assignResult.Fid
	assignUrl := assignResult.Url
	// Prefer same data center
	if fs.option.DataCenter != "" {
		for _, repl := range assignResult.Replicas {
			if repl.DataCenter == fs.option.DataCenter {
				assignUrl = repl.Url
				break
			}
		}
	}
	urlLocation = "http://" + assignUrl + "/" + assignResult.Fid
	if so.Fsync {
		urlLocation += "?fsync=true"
	}
	auth = assignResult.Auth
	return
}

func (fs *FilerServer) PostHandler(w http.ResponseWriter, r *http.Request, contentLength int64) {
	ctx := r.Context()

	// Match storage rules on the decoded path the entry is written to. The raw
	// request-target is percent-encoded on the wire, so a rule on "/只读/" would
	// never see "/%E5%8F%AA%E8%AF%BB/".
	destination := r.URL.Path
	headerDestination := r.Header.Get(s3_constants.SeaweedStorageDestinationHeader)
	if headerDestination != "" {
		destination = headerDestination
	}

	// The destination header picks storage rules for a logical destination, but
	// the entry is written at r.URL.Path. Enforce the read-only/quota rule on the
	// actual write path too, so the header cannot route a write into a read-only
	// location.
	if headerDestination != "" && fs.filer.FilerConf.MatchStorageRule(r.URL.Path).ReadOnly {
		writeJsonError(w, r, http.StatusInsufficientStorage, ErrReadOnly)
		return
	}

	query := r.URL.Query()
	so, err := fs.detectStorageOption0(ctx, destination,
		query.Get("collection"),
		query.Get("replication"),
		query.Get("ttl"),
		query.Get("disk"),
		query.Get("fsync"),
		query.Get("dataCenter"),
		query.Get("rack"),
		query.Get("dataNode"),
		query.Get("saveInside"),
	)
	if err != nil {
		if errors.Is(err, ErrReadOnly) {
			writeJsonError(w, r, http.StatusInsufficientStorage, err)
		} else {
			glog.V(1).InfolnCtx(ctx, "post", r.RequestURI, ":", err.Error())
			w.WriteHeader(http.StatusInternalServerError)
		}
		return
	}

	if util.FullPath(r.URL.Path).IsLongerFileName(so.MaxFileNameLength) {
		glog.V(1).InfolnCtx(ctx, "post", r.RequestURI, ": ", "entry name too long")
		w.WriteHeader(http.StatusRequestURITooLong)
		return
	}

	// When DiskType is empty,use filer's -disk
	if so.DiskType == "" {
		so.DiskType = fs.option.DiskType
	}

	if strings.HasPrefix(r.URL.Path, "/etc") {
		so.SaveInside = true
	}

	if query.Has("mv.from") {
		fs.move(ctx, w, r, so)
	} else if query.Has("cp.from") {
		fs.copy(ctx, w, r, so)
	} else {
		fs.autoChunk(ctx, w, r, contentLength, so)
	}

	util_http.CloseRequest(r)

}

func (fs *FilerServer) move(ctx context.Context, w http.ResponseWriter, r *http.Request, so *operation.StorageOption) {
	src := r.URL.Query().Get("mv.from")
	dst := r.URL.Path

	glog.V(2).InfofCtx(ctx, "FilerServer.move %v to %v", src, dst)

	var err error
	if src, err = clearName(src); err != nil {
		writeJsonError(w, r, http.StatusBadRequest, err)
		return
	}
	if dst, err = clearName(dst); err != nil {
		writeJsonError(w, r, http.StatusBadRequest, err)
		return
	}
	src = strings.TrimRight(src, "/")
	if src == "" {
		err = fmt.Errorf("invalid source '/'")
		writeJsonError(w, r, http.StatusBadRequest, err)
		return
	}

	srcPath := util.FullPath(src)
	dstPath := util.FullPath(dst)
	if dstPath.IsLongerFileName(so.MaxFileNameLength) {
		err = fmt.Errorf("dst name to long")
		writeJsonError(w, r, http.StatusBadRequest, err)
		return
	}
	srcEntry, err := fs.filer.FindEntry(ctx, srcPath)
	if err != nil {
		err = fmt.Errorf("failed to get src entry '%s', err: %s", src, err)
		writeJsonError(w, r, http.StatusBadRequest, err)
		return
	}

	wormEnforced, err := fs.wormEnforcedForEntry(ctx, src)
	if err != nil {
		writeJsonError(w, r, http.StatusInternalServerError, err)
		return
	} else if wormEnforced {
		// you cannot move a worm file or directory
		err = fmt.Errorf("cannot move write-once entry from '%s' to '%s': %s", src, dst, constants.ErrMsgOperationNotPermitted)
		writeJsonError(w, r, http.StatusForbidden, err)
		return
	}

	oldDir, oldName := srcPath.DirAndName()
	newDir, newName := dstPath.DirAndName()
	newName = util.Nvl(newName, oldName)

	dstEntry, err := fs.filer.FindEntry(ctx, util.FullPath(strings.TrimRight(dst, "/")))
	if err != nil && err != filer_pb.ErrNotFound {
		err = fmt.Errorf("failed to get dst entry '%s', err: %s", dst, err)
		writeJsonError(w, r, http.StatusInternalServerError, err)
		return
	}
	if err == nil && !dstEntry.IsDirectory() && srcEntry.IsDirectory() {
		err = fmt.Errorf("move: cannot overwrite non-directory '%s' with directory '%s'", dst, src)
		writeJsonError(w, r, http.StatusBadRequest, err)
		return
	}

	_, err = fs.AtomicRenameEntry(ctx, &filer_pb.AtomicRenameEntryRequest{
		OldDirectory: oldDir,
		OldName:      oldName,
		NewDirectory: newDir,
		NewName:      newName,
	})
	if err != nil {
		err = fmt.Errorf("failed to move entry from '%s' to '%s', err: %s", src, dst, err)
		writeJsonError(w, r, http.StatusBadRequest, err)
		return
	}

	w.WriteHeader(http.StatusNoContent)
}

// curl -X DELETE http://localhost:8888/path/to
// curl -X DELETE http://localhost:8888/path/to?recursive=true
// curl -X DELETE http://localhost:8888/path/to?recursive=true&ignoreRecursiveError=true
// curl -X DELETE http://localhost:8888/path/to?recursive=true&skipChunkDeletion=true
func (fs *FilerServer) DeleteHandler(w http.ResponseWriter, r *http.Request) {
	isRecursive := r.FormValue("recursive") == "true"
	if !isRecursive && fs.option.recursiveDelete {
		if r.FormValue("recursive") != "false" {
			isRecursive = true
		}
	}
	ignoreRecursiveError := r.FormValue("ignoreRecursiveError") == "true"
	skipChunkDeletion := r.FormValue("skipChunkDeletion") == "true"

	objectPath := r.URL.Path
	if len(r.URL.Path) > 1 && strings.HasSuffix(objectPath, "/") {
		objectPath = objectPath[0 : len(objectPath)-1]
	}

	wormEnforced, err := fs.wormEnforcedForEntry(context.TODO(), objectPath)
	if err != nil {
		writeJsonError(w, r, http.StatusInternalServerError, err)
		return
	} else if wormEnforced {
		writeJsonError(w, r, http.StatusForbidden, errors.New(constants.ErrMsgOperationNotPermitted))
		return
	}

	err = fs.filer.DeleteEntryMetaAndData(context.Background(), util.FullPath(objectPath), isRecursive, ignoreRecursiveError, !skipChunkDeletion, false, nil, 0)
	if err != nil && err != filer_pb.ErrNotFound {
		glog.V(1).Infoln("deleting", objectPath, ":", err.Error())
		writeJsonError(w, r, http.StatusInternalServerError, err)
		return
	}

	w.WriteHeader(http.StatusNoContent)
}

func (fs *FilerServer) detectStorageOption(ctx context.Context, requestURI, qCollection, qReplication string, ttlSeconds int32, diskType, dataCenter, rack, dataNode string) (*operation.StorageOption, error) {

	rule := fs.filer.FilerConf.MatchStorageRule(requestURI)

	if rule.ReadOnly {
		// Name the read-only prefix so the caller knows which path is locked and why.
		// MatchStorageRule leaves LocationPrefix empty when several rules merge; fall back to the request path.
		prefix := rule.LocationPrefix
		if prefix == "" {
			prefix = requestURI
		}
		return nil, fmt.Errorf("%w: %s (e.g. bucket over quota)", ErrReadOnly, prefix)
	}

	// Use local variable instead of mutating shared rule
	maxFileNameLength := rule.MaxFileNameLength
	if maxFileNameLength == 0 {
		maxFileNameLength = fs.filer.MaxFilenameLength
	}

	// required by buckets folder
	bucketDefaultCollection := ""
	if strings.HasPrefix(requestURI, fs.filer.DirBucketsPath+"/") {
		bucketDefaultCollection = fs.filer.DetectBucket(util.FullPath(requestURI))
	}

	if ttlSeconds == 0 {
		ttl, err := needle.ReadTTL(rule.GetTtl())
		if err != nil {
			glog.ErrorfCtx(ctx, "fail to parse %s ttl setting %s: %v", rule.LocationPrefix, rule.Ttl, err)
		}
		ttlSeconds = int32(ttl.Minutes()) * 60
	}

	collection := util.Nvl(qCollection, rule.Collection, bucketDefaultCollection, fs.option.Collection)

	// A placement overlay steers a bound collection's new volumes onto a tier.
	// It sits between the explicit request and the filer.conf rule: it overrides
	// the rule but yields to a value the caller asked for outright. Only a
	// steered collection contributes values; an unsteered one clears them so it
	// falls straight through to the rule.
	overlayDisk, overlayReplication, overlayDataCenter, overlaySteered := fs.filer.ResolvePlacement(collection)
	if !overlaySteered {
		overlayDisk, overlayReplication, overlayDataCenter = "", "", ""
	} else {
		glog.V(4).InfofCtx(ctx, "placement overlay steers collection %s: disk=%q replication=%q dataCenter=%q",
			collection, overlayDisk, overlayReplication, overlayDataCenter)
	}

	return &operation.StorageOption{
		Replication:       util.Nvl(qReplication, overlayReplication, rule.Replication, fs.option.DefaultReplication),
		Collection:        collection,
		DataCenter:        util.Nvl(dataCenter, overlayDataCenter, rule.DataCenter, fs.option.DataCenter),
		Rack:              util.Nvl(rack, rule.Rack, fs.option.Rack),
		DataNode:          util.Nvl(dataNode, rule.DataNode, fs.option.DataNode),
		TtlSeconds:        ttlSeconds,
		DiskType:          util.Nvl(diskType, overlayDisk, rule.DiskType),
		Fsync:             rule.Fsync,
		VolumeGrowthCount: rule.VolumeGrowthCount,
		MaxFileNameLength: maxFileNameLength,
	}, nil
}

func (fs *FilerServer) detectStorageOption0(ctx context.Context, requestURI, qCollection, qReplication string, qTtl string, diskType string, fsync string, dataCenter, rack, dataNode, saveInside string) (*operation.StorageOption, error) {

	ttl, err := needle.ReadTTL(qTtl)
	if err != nil {
		glog.ErrorfCtx(ctx, "fail to parse ttl %s: %v", qTtl, err)
	}

	so, err := fs.detectStorageOption(ctx, requestURI, qCollection, qReplication, int32(ttl.Minutes())*60, diskType, dataCenter, rack, dataNode)
	if so != nil {
		if fsync == "false" {
			so.Fsync = false
		} else if fsync == "true" {
			so.Fsync = true
		}
		if saveInside == "true" {
			so.SaveInside = true
		} else {
			so.SaveInside = false
		}
	}

	return so, err
}
