package api

import (
	"context"
	"sync"
)

type (
	// KeyVal - appended to ReqInfo.Tags
	KeyVal struct {
		Key string
		Val string
	}

	// ReqInfo stores the request info.
	ReqInfo struct {
		sync.RWMutex
		RemoteHost   string   // Client Host/IP
		Host         string   // Node Host/IP
		UserAgent    string   // User Agent
		DeploymentID string   // x-minio-deployment-id
		RequestID    string   // x-amz-request-id
		API          string   // API name - GetObject PutObject NewMultipartUpload etc.
		BucketName   string   // Bucket name
		ObjectName   string   // Object name
		tags         []KeyVal // Any additional info not accommodated by above fields
	}
)

// Key used for Get/SetReqInfo
type contextKeyType string

const ctxRequestInfo = contextKeyType("NeoFS-S3-Gate")

// NewReqInfo :
func NewReqInfo(remoteHost, userAgent, deploymentID, requestID, api, bucket, object string) *ReqInfo {
	req := ReqInfo{}
	req.RemoteHost = remoteHost
	req.UserAgent = userAgent
	req.API = api
	req.DeploymentID = deploymentID
	req.RequestID = requestID
	req.BucketName = bucket
	req.ObjectName = object
	return &req
}

// AppendTags - appends key/val to ReqInfo.tags
func (r *ReqInfo) AppendTags(key string, val string) *ReqInfo {
	if r == nil {
		return nil
	}
	r.Lock()
	defer r.Unlock()
	r.tags = append(r.tags, KeyVal{key, val})
	return r
}

// SetTags - sets key/val to ReqInfo.tags
func (r *ReqInfo) SetTags(key string, val string) *ReqInfo {
	if r == nil {
		return nil
	}
	r.Lock()
	defer r.Unlock()
	// Search of tag key already exists in tags
	var updated bool
	for _, tag := range r.tags {
		if tag.Key == key {
			tag.Val = val
			updated = true
			break
		}
	}
	if !updated {
		// Append to the end of tags list
		r.tags = append(r.tags, KeyVal{key, val})
	}
	return r
}

// GetTags - returns the user defined tags
func (r *ReqInfo) GetTags() []KeyVal {
	if r == nil {
		return nil
	}
	r.RLock()
	defer r.RUnlock()
	return append([]KeyVal(nil), r.tags...)
}

// SetReqInfo sets ReqInfo in the context.
func SetReqInfo(ctx context.Context, req *ReqInfo) context.Context {
	if ctx == nil {
		return nil
	}
	return context.WithValue(ctx, ctxRequestInfo, req)
}

// GetReqInfo returns ReqInfo if set.
func GetReqInfo(ctx context.Context) *ReqInfo {
	if ctx != nil {
		r, ok := ctx.Value(ctxRequestInfo).(*ReqInfo)
		if ok {
			return r
		}
		r = &ReqInfo{}
		SetReqInfo(ctx, r)
		return r
	}
	return nil
}