// Copyright 2016 TiKV Project Authors.
//
// Licensed 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,
// See the License for the specific language governing permissions and
// limitations under the License.

package api

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

	"github.com/gorilla/mux"
	"github.com/pingcap/errors"
	"github.com/pingcap/kvproto/pkg/pdpb"
	"github.com/pingcap/log"
	"github.com/tikv/pd/pkg/apiutil"
	"github.com/tikv/pd/pkg/errs"
	"github.com/tikv/pd/pkg/etcdutil"
	"github.com/tikv/pd/server"
	"github.com/unrolled/render"
	"go.uber.org/zap"
)

type memberHandler struct {
	svr *server.Server
	rd  *render.Render
}

func newMemberHandler(svr *server.Server, rd *render.Render) *memberHandler {
	return &memberHandler{
		svr: svr,
		rd:  rd,
	}
}

// @Tags member
// @Summary List all PD servers in the cluster.
// @Produce json
// @Success 200 {object} pdpb.GetMembersResponse
// @Failure 500 {string} string "PD server failed to proceed the request."
// @Router /members [get]
func (h *memberHandler) ListMembers(w http.ResponseWriter, r *http.Request) {
	members, err := h.getMembers()
	if err != nil {
		h.rd.JSON(w, http.StatusInternalServerError, err.Error())
		return
	}
	h.rd.JSON(w, http.StatusOK, members)
}

func (h *memberHandler) getMembers() (*pdpb.GetMembersResponse, error) {
	req := &pdpb.GetMembersRequest{Header: &pdpb.RequestHeader{ClusterId: h.svr.ClusterID()}}
	members, err := h.svr.GetMembers(context.Background(), req)
	if err != nil {
		return nil, errors.WithStack(err)
	}
	for _, m := range members.GetMembers() {
		binaryVersion, e := h.svr.GetMember().GetMemberBinaryVersion(m.GetMemberId())
		if e != nil {
			log.Error("failed to load binary version", zap.Uint64("member", m.GetMemberId()), errs.ZapError(e))
		}
		m.BinaryVersion = binaryVersion
		deployPath, e := h.svr.GetMember().GetMemberDeployPath(m.GetMemberId())
		if e != nil {
			log.Error("failed to load deploy path", zap.Uint64("member", m.GetMemberId()), errs.ZapError(e))
		}
		m.DeployPath = deployPath
		if h.svr.GetMember().GetEtcdLeader() == 0 {
			log.Warn("no etcd leader, skip get leader priority", zap.Uint64("member", m.GetMemberId()))
			continue
		}
		leaderPriority, e := h.svr.GetMember().GetMemberLeaderPriority(m.GetMemberId())
		if e != nil {
			log.Error("failed to load leader priority", zap.Uint64("member", m.GetMemberId()), errs.ZapError(e))
			continue
		}
		m.LeaderPriority = int32(leaderPriority)
		gitHash, e := h.svr.GetMember().GetMemberGitHash(m.GetMemberId())
		if e != nil {
			log.Error("failed to load git hash", zap.Uint64("member", m.GetMemberId()), errs.ZapError(e))
			continue
		}
		m.GitHash = gitHash
	}
	return members, nil
}

// @Tags member
// @Summary Remove a PD server from the cluster.
// @Param name path string true "PD server name"
// @Produce json
// @Success 200 {string} string "The PD server is successfully removed."
// @Failure 400 {string} string "The input is invalid."
// @Failure 404 {string} string "The member does not exist."
// @Failure 500 {string} string "PD server failed to proceed the request."
// @Router /members/name/{name} [delete]
func (h *memberHandler) DeleteByName(w http.ResponseWriter, r *http.Request) {
	client := h.svr.GetClient()

	// Get etcd ID by name.
	var id uint64
	name := mux.Vars(r)["name"]
	listResp, err := etcdutil.ListEtcdMembers(client)
	if err != nil {
		h.rd.JSON(w, http.StatusInternalServerError, err.Error())
		return
	}
	for _, m := range listResp.Members {
		if name == m.Name {
			id = m.ID
			break
		}
	}
	if id == 0 {
		h.rd.JSON(w, http.StatusNotFound, fmt.Sprintf("not found, pd: %s", name))
		return
	}

	// Delete config.
	err = h.svr.GetMember().DeleteMemberLeaderPriority(id)
	if err != nil {
		h.rd.JSON(w, http.StatusInternalServerError, err.Error())
		return
	}

	// Remove member by id
	_, err = etcdutil.RemoveEtcdMember(client, id)
	if err != nil {
		h.rd.JSON(w, http.StatusInternalServerError, err.Error())
		return
	}
	h.rd.JSON(w, http.StatusOK, fmt.Sprintf("removed, pd: %s", name))
}

// @Tags member
// @Summary Remove a PD server from the cluster.
// @Param id path integer true "PD server Id"
// @Produce json
// @Success 200 {string} string "The PD server is successfully removed."
// @Failure 400 {string} string "The input is invalid."
// @Failure 500 {string} string "PD server failed to proceed the request."
// @Router /members/id/{id} [delete]
func (h *memberHandler) DeleteByID(w http.ResponseWriter, r *http.Request) {
	idStr := mux.Vars(r)["id"]
	id, err := strconv.ParseUint(idStr, 10, 64)
	if err != nil {
		h.rd.JSON(w, http.StatusBadRequest, err.Error())
		return
	}

	// Delete config.
	err = h.svr.GetMember().DeleteMemberLeaderPriority(id)
	if err != nil {
		h.rd.JSON(w, http.StatusInternalServerError, err.Error())
		return
	}

	client := h.svr.GetClient()
	_, err = etcdutil.RemoveEtcdMember(client, id)
	if err != nil {
		h.rd.JSON(w, http.StatusInternalServerError, err.Error())
		return
	}
	h.rd.JSON(w, http.StatusOK, fmt.Sprintf("removed, pd: %v", id))
}

// FIXME: details of input json body params
// @Tags member
// @Summary Set leader priority of a PD member.
// @Accept json
// @Param name path string true "PD server name"
// @Param body body object true "json params"
// @Produce json
// @Success 200 {string} string "The leader priority is updated."
// @Failure 400 {string} string "The input is invalid."
// @Failure 404 {string} string "The member does not exist."
// @Failure 500 {string} string "PD server failed to proceed the request."
// @Router /members/name/{name} [post]
func (h *memberHandler) SetMemberPropertyByName(w http.ResponseWriter, r *http.Request) {
	members, membersErr := h.getMembers()
	if membersErr != nil {
		h.rd.JSON(w, http.StatusInternalServerError, membersErr.Error())
		return
	}

	var memberID uint64
	name := mux.Vars(r)["name"]
	for _, m := range members.GetMembers() {
		if m.GetName() == name {
			memberID = m.GetMemberId()
			break
		}
	}
	if memberID == 0 {
		h.rd.JSON(w, http.StatusNotFound, fmt.Sprintf("not found, pd: %s", name))
		return
	}

	var input map[string]interface{}
	if err := apiutil.ReadJSONRespondError(h.rd, w, r.Body, &input); err != nil {
		return
	}
	for k, v := range input {
		switch k {
		case "leader-priority":
			priority, ok := v.(float64)
			if !ok {
				h.rd.JSON(w, http.StatusBadRequest, "bad format leader priority")
				return
			}
			err := h.svr.GetMember().SetMemberLeaderPriority(memberID, int(priority))
			if err != nil {
				h.rd.JSON(w, http.StatusInternalServerError, err.Error())
				return
			}
		}
	}
	h.rd.JSON(w, http.StatusOK, "success")
}

type leaderHandler struct {
	svr *server.Server
	rd  *render.Render
}

func newLeaderHandler(svr *server.Server, rd *render.Render) *leaderHandler {
	return &leaderHandler{
		svr: svr,
		rd:  rd,
	}
}

// @Tags leader
// @Summary Get the leader PD server of the cluster.
// @Produce json
// @Success 200 {string} string "The transfer command is submitted."
// @Router /leader [get]
func (h *leaderHandler) Get(w http.ResponseWriter, r *http.Request) {
	h.rd.JSON(w, http.StatusOK, h.svr.GetLeader())
}

// @Tags leader
// @Summary Transfer leadership to another PD server.
// @Produce json
// @Success 200 {string} string "The transfer command is submitted."
// @Failure 500 {string} string "PD server failed to proceed the request."
// @Router /leader/resign [post]
func (h *leaderHandler) Resign(w http.ResponseWriter, r *http.Request) {
	err := h.svr.GetMember().ResignLeader(h.svr.Context(), h.svr.Name(), "")
	if err != nil {
		h.rd.JSON(w, http.StatusInternalServerError, err.Error())
		return
	}

	h.rd.JSON(w, http.StatusOK, nil)
}

// @Tags leader
// @Summary Transfer leadership to the specific PD server.
// @Param nextLeader path string true "PD server that transfer leader to"
// @Produce json
// @Success 200 {string} string "The transfer command is submitted."
// @Failure 500 {string} string "PD server failed to proceed the request."
// @Router /leader/transfer/{nextLeader} [post]
func (h *leaderHandler) Transfer(w http.ResponseWriter, r *http.Request) {
	err := h.svr.GetMember().ResignLeader(h.svr.Context(), h.svr.Name(), mux.Vars(r)["next_leader"])
	if err != nil {
		h.rd.JSON(w, http.StatusInternalServerError, err.Error())
		return
	}

	h.rd.JSON(w, http.StatusOK, nil)
}