/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package v1

import (
	"context"
	"encoding/json"
	"errors"
	"github.com/apache/servicecomb-kie/pkg/model"
	"net/http"
	"strconv"
	"strings"
	"time"

	"github.com/apache/servicecomb-kie/pkg/common"
	"github.com/apache/servicecomb-kie/server/pubsub"
	"github.com/apache/servicecomb-kie/server/service"
	goRestful "github.com/emicklei/go-restful"
	"github.com/go-chassis/go-chassis/server/restful"
	"github.com/go-mesh/openlogging"
	uuid "github.com/satori/go.uuid"
	"gopkg.in/yaml.v2"
)

//const of server
const (
	HeaderUserAgent      = "User-Agent"
	HeaderSessionID      = "sessionID"
	PathParameterProject = "project"
	PathParameterKey     = "key"
	AttributeDomainKey   = "domain"
	MsgLabelsNotFound    = "can not find by labels"
)

//err
var (
	ErrInvalidRev = errors.New(common.MsgInvalidRev)
)

//ReadDomain get domain info from attribute
func ReadDomain(context *restful.Context) interface{} {
	return context.ReadRestfulRequest().Attribute(AttributeDomainKey)
}

//ReadFindDepth get find depth
func ReadFindDepth(context *restful.Context) (int, error) {
	d := context.ReadRestfulRequest().HeaderParameter(common.HeaderDepth)
	if d == "" {
		return 1, nil
	}
	depth, err := strconv.Atoi(d)
	if err != nil {
		return 0, err
	}
	return depth, nil
}

//ReadLabelCombinations get query combination from url
//q=app:default+service:payment&q=app:default
func ReadLabelCombinations(req *goRestful.Request) ([]map[string]string, error) {
	queryCombinations := req.QueryParameters(common.QueryParamQ)
	labelCombinations := make([]map[string]string, 0)
	for _, queryStr := range queryCombinations {
		labelStr := strings.Split(queryStr, " ")
		labels := make(map[string]string, len(labelStr))
		for _, label := range labelStr {
			l := strings.Split(label, ":")
			if len(l) != 2 {
				return nil, errors.New("wrong query syntax:" + label)
			}
			labels[l[0]] = l[1]
		}
		if len(labels) == 0 {
			continue
		}
		labelCombinations = append(labelCombinations, labels)
	}
	if len(labelCombinations) == 0 {
		return []map[string]string{{"default": "default"}}, nil
	}

	return labelCombinations, nil
}

//WriteErrResponse write error message to client
func WriteErrResponse(context *restful.Context, status int, msg, contentType string) {
	context.WriteHeader(status)
	b, _ := json.MarshalIndent(&ErrorMsg{Msg: msg}, "", " ")
	context.ReadRestfulResponse().AddHeader(goRestful.HEADER_ContentType, contentType)
	context.Write(b)

}

func readRequest(ctx *restful.Context, v interface{}) error {
	if ctx.ReadHeader(common.HeaderContentType) == common.ContentTypeYaml {
		return yaml.NewDecoder(ctx.ReadRequest().Body).Decode(v)
	}
	return json.NewDecoder(ctx.ReadRequest().Body).Decode(v) // json is default
}

func writeYaml(resp *goRestful.Response, v interface{}) error {
	if v == nil {
		resp.WriteHeader(http.StatusOK)
		return nil
	}
	resp.Header().Set(common.HeaderContentType, common.ContentTypeYaml)
	resp.WriteHeader(http.StatusOK)
	return yaml.NewEncoder(resp).Encode(v)
}

func writeResponse(ctx *restful.Context, v interface{}) error {
	if ctx.ReadHeader(common.HeaderAccept) == common.ContentTypeYaml {
		return writeYaml(ctx.Resp, v)
	}
	return ctx.WriteJSON(v, goRestful.MIME_JSON) // json is default
}
func getLabels(rctx *restful.Context) (map[string]string, error) {
	labelSlice := rctx.Req.QueryParameters(common.QueryParamLabel)
	if len(labelSlice) == 0 {
		return nil, nil
	}
	labels := make(map[string]string, len(labelSlice))
	for _, v := range labelSlice {
		v := strings.Split(v, ":")
		if len(v) != 2 {
			return nil, errors.New(common.MsgIllegalLabels)
		}
		labels[v[0]] = v[1]
	}
	return labels, nil
}
func isRevised(ctx context.Context, revStr, domain string) (bool, error) {
	rev, err := strconv.ParseInt(revStr, 10, 64)
	if err != nil {
		return false, ErrInvalidRev
	}
	latest, err := service.RevisionService.GetRevision(ctx, domain)
	if err != nil {
		return false, err
	}
	if latest > rev {
		return true, nil
	}
	return false, nil
}
func getMatchPattern(rctx *restful.Context) string {
	m := rctx.ReadQueryParameter(common.QueryParamMatch)
	if m != "" && m != common.PatternExact {
		return ""
	}
	return m
}
func eventHappened(rctx *restful.Context, waitStr string, topic *pubsub.Topic) (bool, error) {
	d, err := time.ParseDuration(waitStr)
	if err != nil || d > common.MaxWait {
		return false, errors.New(common.MsgInvalidWait)
	}
	happened := true
	o := &pubsub.Observer{
		UUID:      uuid.NewV4().String(),
		RemoteIP:  rctx.ReadRequest().RemoteAddr, //TODO x forward ip
		UserAgent: rctx.ReadHeader(HeaderUserAgent),
		Event:     make(chan *pubsub.KVChangeEvent, 1),
	}
	err = pubsub.ObserveOnce(o, topic)
	if err != nil {
		return false, errors.New("observe once failed: " + err.Error())
	}
	select {
	case <-time.After(d):
		happened = false
	case <-o.Event:
	}
	return happened, nil
}

// size from 1 to start
func checkPagination(offsetStr, limitStr string) (int64, int64, error) {
	var err error
	var offset, limit int64
	if offsetStr != "" {
		offset, err = strconv.ParseInt(offsetStr, 10, 64)
		if err != nil {
			return 0, 0, err
		}
		if offset < 0 {
			return 0, 0, errors.New("invalid offset number")
		}
	}

	if limitStr != "" {
		limit, err = strconv.ParseInt(limitStr, 10, 64)
		if err != nil || (limit < 1 || limit > 100) {
			return 0, 0, errors.New("invalid limit number")
		}
	}
	return offset, limit, err
}

func checkStatus(status string) (string, error) {
	if status != "" {
		if status != common.StatusEnabled && status != common.StatusDisabled {
			return "", errors.New("invalid status string")
		}
	}
	return status, nil
}

func queryAndResponse(rctx *restful.Context, doc *model.KVDoc, offset, limit int64) {
	m := getMatchPattern(rctx)
	opts := []service.FindOption{
		service.WithKey(doc.Key),
		service.WithLabels(doc.Labels),
		service.WithOffset(offset),
		service.WithLimit(limit),
	}
	if m == common.PatternExact {
		opts = append(opts, service.WithExactLabels())
	}
	if doc.Status != "" {
		opts = append(opts, service.WithStatus(doc.Status))
	}
	rev, err := service.RevisionService.GetRevision(rctx.Ctx, doc.Domain)
	if err != nil {
		WriteErrResponse(rctx, http.StatusInternalServerError, err.Error(), common.ContentTypeText)
		return
	}
	kv, err := service.KVService.List(rctx.Ctx, doc.Domain, doc.Project, opts...)
	if err != nil {
		if err == service.ErrKeyNotExists {
			rctx.ReadResponseWriter().Header().Set(common.HeaderRevision, strconv.FormatInt(rev, 10))
			WriteErrResponse(rctx, http.StatusNotFound, err.Error(), common.ContentTypeText)
			return
		}
		WriteErrResponse(rctx, http.StatusInternalServerError, err.Error(), common.ContentTypeText)
		return
	}
	rctx.ReadResponseWriter().Header().Set(common.HeaderRevision, strconv.FormatInt(rev, 10))
	err = writeResponse(rctx, kv)
	rctx.Ctx = context.WithValue(rctx.Ctx, common.RespBodyContextKey, kv)
	if err != nil {
		openlogging.Error(err.Error())
	}
}