package rest

import (
	"errors"
	"fmt"
	"net/http"

	"github.com/gorilla/mux"

	"github.com/cosmos/cosmos-sdk/client/context"
	sdk "github.com/cosmos/cosmos-sdk/types"
	"github.com/cosmos/cosmos-sdk/types/rest"
	gcutils "github.com/cosmos/cosmos-sdk/x/gov/client/utils"
	"github.com/cosmos/cosmos-sdk/x/gov/types"
)

func registerQueryRoutes(cliCtx context.CLIContext, r *mux.Router) {
	r.HandleFunc(fmt.Sprintf("/gov/parameters/{%s}", RestParamsType), queryParamsHandlerFn(cliCtx)).Methods("GET")
	r.HandleFunc("/gov/proposals", queryProposalsWithParameterFn(cliCtx)).Methods("GET")
	r.HandleFunc(fmt.Sprintf("/gov/proposals/{%s}", RestProposalID), queryProposalHandlerFn(cliCtx)).Methods("GET")
	r.HandleFunc(fmt.Sprintf("/gov/proposals/{%s}/proposer", RestProposalID), queryProposerHandlerFn(cliCtx)).Methods("GET")
	r.HandleFunc(fmt.Sprintf("/gov/proposals/{%s}/deposits", RestProposalID), queryDepositsHandlerFn(cliCtx)).Methods("GET")
	r.HandleFunc(fmt.Sprintf("/gov/proposals/{%s}/deposits/{%s}", RestProposalID, RestDepositor), queryDepositHandlerFn(cliCtx)).Methods("GET")
	r.HandleFunc(fmt.Sprintf("/gov/proposals/{%s}/tally", RestProposalID), queryTallyOnProposalHandlerFn(cliCtx)).Methods("GET")
	r.HandleFunc(fmt.Sprintf("/gov/proposals/{%s}/votes", RestProposalID), queryVotesOnProposalHandlerFn(cliCtx)).Methods("GET")
	r.HandleFunc(fmt.Sprintf("/gov/proposals/{%s}/votes/{%s}", RestProposalID, RestVoter), queryVoteHandlerFn(cliCtx)).Methods("GET")
}

func queryParamsHandlerFn(cliCtx context.CLIContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		vars := mux.Vars(r)
		paramType := vars[RestParamsType]

		cliCtx, ok := rest.ParseQueryHeightOrReturnBadRequest(w, cliCtx, r)
		if !ok {
			return
		}

		res, height, err := cliCtx.QueryWithData(fmt.Sprintf("custom/gov/%s/%s", types.QueryParams, paramType), nil)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusNotFound, err.Error())
			return
		}

		cliCtx = cliCtx.WithHeight(height)
		rest.PostProcessResponse(w, cliCtx, res)
	}
}

func queryProposalHandlerFn(cliCtx context.CLIContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		vars := mux.Vars(r)
		strProposalID := vars[RestProposalID]

		if len(strProposalID) == 0 {
			err := errors.New("proposalId required but not specified")
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		proposalID, ok := rest.ParseUint64OrReturnBadRequest(w, strProposalID)
		if !ok {
			return
		}

		cliCtx, ok = rest.ParseQueryHeightOrReturnBadRequest(w, cliCtx, r)
		if !ok {
			return
		}

		params := types.NewQueryProposalParams(proposalID)

		bz, err := cliCtx.Codec.MarshalJSON(params)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		res, height, err := cliCtx.QueryWithData("custom/gov/proposal", bz)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusInternalServerError, err.Error())
			return
		}

		cliCtx = cliCtx.WithHeight(height)
		rest.PostProcessResponse(w, cliCtx, res)
	}
}

func queryDepositsHandlerFn(cliCtx context.CLIContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		vars := mux.Vars(r)
		strProposalID := vars[RestProposalID]

		proposalID, ok := rest.ParseUint64OrReturnBadRequest(w, strProposalID)
		if !ok {
			return
		}

		cliCtx, ok = rest.ParseQueryHeightOrReturnBadRequest(w, cliCtx, r)
		if !ok {
			return
		}

		params := types.NewQueryProposalParams(proposalID)

		bz, err := cliCtx.Codec.MarshalJSON(params)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		res, _, err := cliCtx.QueryWithData("custom/gov/proposal", bz)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusInternalServerError, err.Error())
			return
		}

		var proposal types.Proposal
		if err := cliCtx.Codec.UnmarshalJSON(res, &proposal); err != nil {
			rest.WriteErrorResponse(w, http.StatusInternalServerError, err.Error())
			return
		}

		// For inactive proposals we must query the txs directly to get the deposits
		// as they're no longer in state.
		propStatus := proposal.Status
		if !(propStatus == types.StatusVotingPeriod || propStatus == types.StatusDepositPeriod) {
			res, err = gcutils.QueryDepositsByTxQuery(cliCtx, params)
		} else {
			res, _, err = cliCtx.QueryWithData("custom/gov/deposits", bz)
		}

		if err != nil {
			rest.WriteErrorResponse(w, http.StatusInternalServerError, err.Error())
			return
		}

		rest.PostProcessResponse(w, cliCtx, res)
	}
}

func queryProposerHandlerFn(cliCtx context.CLIContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		vars := mux.Vars(r)
		strProposalID := vars[RestProposalID]

		proposalID, ok := rest.ParseUint64OrReturnBadRequest(w, strProposalID)
		if !ok {
			return
		}

		cliCtx, ok = rest.ParseQueryHeightOrReturnBadRequest(w, cliCtx, r)
		if !ok {
			return
		}

		res, err := gcutils.QueryProposerByTxQuery(cliCtx, proposalID)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusInternalServerError, err.Error())
			return
		}

		rest.PostProcessResponse(w, cliCtx, res)
	}
}

func queryDepositHandlerFn(cliCtx context.CLIContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		vars := mux.Vars(r)
		strProposalID := vars[RestProposalID]
		bechDepositorAddr := vars[RestDepositor]

		if len(strProposalID) == 0 {
			err := errors.New("proposalId required but not specified")
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		proposalID, ok := rest.ParseUint64OrReturnBadRequest(w, strProposalID)
		if !ok {
			return
		}

		if len(bechDepositorAddr) == 0 {
			err := errors.New("depositor address required but not specified")
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		depositorAddr, err := sdk.AccAddressFromBech32(bechDepositorAddr)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		cliCtx, ok = rest.ParseQueryHeightOrReturnBadRequest(w, cliCtx, r)
		if !ok {
			return
		}

		params := types.NewQueryDepositParams(proposalID, depositorAddr)

		bz, err := cliCtx.Codec.MarshalJSON(params)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		res, _, err := cliCtx.QueryWithData("custom/gov/deposit", bz)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusInternalServerError, err.Error())
			return
		}

		var deposit types.Deposit
		if err := cliCtx.Codec.UnmarshalJSON(res, &deposit); err != nil {
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		// For an empty deposit, either the proposal does not exist or is inactive in
		// which case the deposit would be removed from state and should be queried
		// for directly via a txs query.
		if deposit.Empty() {
			bz, err := cliCtx.Codec.MarshalJSON(types.NewQueryProposalParams(proposalID))
			if err != nil {
				rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
				return
			}

			res, _, err = cliCtx.QueryWithData("custom/gov/proposal", bz)
			if err != nil || len(res) == 0 {
				err := fmt.Errorf("proposalID %d does not exist", proposalID)
				rest.WriteErrorResponse(w, http.StatusNotFound, err.Error())
				return
			}

			res, err = gcutils.QueryDepositByTxQuery(cliCtx, params)
			if err != nil {
				rest.WriteErrorResponse(w, http.StatusInternalServerError, err.Error())
				return
			}
		}

		rest.PostProcessResponse(w, cliCtx, res)
	}
}

func queryVoteHandlerFn(cliCtx context.CLIContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		vars := mux.Vars(r)
		strProposalID := vars[RestProposalID]
		bechVoterAddr := vars[RestVoter]

		if len(strProposalID) == 0 {
			err := errors.New("proposalId required but not specified")
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		proposalID, ok := rest.ParseUint64OrReturnBadRequest(w, strProposalID)
		if !ok {
			return
		}

		if len(bechVoterAddr) == 0 {
			err := errors.New("voter address required but not specified")
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		voterAddr, err := sdk.AccAddressFromBech32(bechVoterAddr)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		cliCtx, ok = rest.ParseQueryHeightOrReturnBadRequest(w, cliCtx, r)
		if !ok {
			return
		}

		params := types.NewQueryVoteParams(proposalID, voterAddr)

		bz, err := cliCtx.Codec.MarshalJSON(params)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		res, _, err := cliCtx.QueryWithData("custom/gov/vote", bz)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusInternalServerError, err.Error())
			return
		}

		var vote types.Vote
		if err := cliCtx.Codec.UnmarshalJSON(res, &vote); err != nil {
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		// For an empty vote, either the proposal does not exist or is inactive in
		// which case the vote would be removed from state and should be queried for
		// directly via a txs query.
		if vote.Empty() {
			bz, err := cliCtx.Codec.MarshalJSON(types.NewQueryProposalParams(proposalID))
			if err != nil {
				rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
				return
			}

			res, _, err = cliCtx.QueryWithData("custom/gov/proposal", bz)
			if err != nil || len(res) == 0 {
				err := fmt.Errorf("proposalID %d does not exist", proposalID)
				rest.WriteErrorResponse(w, http.StatusNotFound, err.Error())
				return
			}

			res, err = gcutils.QueryVoteByTxQuery(cliCtx, params)
			if err != nil {
				rest.WriteErrorResponse(w, http.StatusInternalServerError, err.Error())
				return
			}
		}

		rest.PostProcessResponse(w, cliCtx, res)
	}
}

// todo: Split this functionality into helper functions to remove the above
func queryVotesOnProposalHandlerFn(cliCtx context.CLIContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		_, page, limit, err := rest.ParseHTTPArgsWithLimit(r, 0)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		vars := mux.Vars(r)
		strProposalID := vars[RestProposalID]

		if len(strProposalID) == 0 {
			err := errors.New("proposalId required but not specified")
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		proposalID, ok := rest.ParseUint64OrReturnBadRequest(w, strProposalID)
		if !ok {
			return
		}

		cliCtx, ok = rest.ParseQueryHeightOrReturnBadRequest(w, cliCtx, r)
		if !ok {
			return
		}

		params := types.NewQueryProposalVotesParams(proposalID, page, limit)

		bz, err := cliCtx.Codec.MarshalJSON(params)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		res, _, err := cliCtx.QueryWithData("custom/gov/proposal", bz)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusInternalServerError, err.Error())
			return
		}

		var proposal types.Proposal
		if err := cliCtx.Codec.UnmarshalJSON(res, &proposal); err != nil {
			rest.WriteErrorResponse(w, http.StatusInternalServerError, err.Error())
			return
		}

		// For inactive proposals we must query the txs directly to get the votes
		// as they're no longer in state.
		propStatus := proposal.Status
		if !(propStatus == types.StatusVotingPeriod || propStatus == types.StatusDepositPeriod) {
			res, err = gcutils.QueryVotesByTxQuery(cliCtx, params)
		} else {
			res, _, err = cliCtx.QueryWithData("custom/gov/votes", bz)
		}

		if err != nil {
			rest.WriteErrorResponse(w, http.StatusInternalServerError, err.Error())
			return
		}

		rest.PostProcessResponse(w, cliCtx, res)
	}
}

// HTTP request handler to query list of governance proposals
func queryProposalsWithParameterFn(cliCtx context.CLIContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		_, page, limit, err := rest.ParseHTTPArgsWithLimit(r, 0)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		cliCtx, ok := rest.ParseQueryHeightOrReturnBadRequest(w, cliCtx, r)
		if !ok {
			return
		}

		var (
			voterAddr      sdk.AccAddress
			depositorAddr  sdk.AccAddress
			proposalStatus types.ProposalStatus
		)

		if v := r.URL.Query().Get(RestVoter); len(v) != 0 {
			voterAddr, err = sdk.AccAddressFromBech32(v)
			if err != nil {
				rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
				return
			}
		}

		if v := r.URL.Query().Get(RestDepositor); len(v) != 0 {
			depositorAddr, err = sdk.AccAddressFromBech32(v)
			if err != nil {
				rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
				return
			}
		}

		if v := r.URL.Query().Get(RestProposalStatus); len(v) != 0 {
			proposalStatus, err = types.ProposalStatusFromString(gcutils.NormalizeProposalStatus(v))
			if err != nil {
				rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
				return
			}
		}

		params := types.NewQueryProposalsParams(page, limit, proposalStatus, voterAddr, depositorAddr)
		bz, err := cliCtx.Codec.MarshalJSON(params)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		route := fmt.Sprintf("custom/%s/%s", types.QuerierRoute, types.QueryProposals)
		res, height, err := cliCtx.QueryWithData(route, bz)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusInternalServerError, err.Error())
			return
		}

		cliCtx = cliCtx.WithHeight(height)
		rest.PostProcessResponse(w, cliCtx, res)
	}
}

// todo: Split this functionality into helper functions to remove the above
func queryTallyOnProposalHandlerFn(cliCtx context.CLIContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		vars := mux.Vars(r)
		strProposalID := vars[RestProposalID]

		if len(strProposalID) == 0 {
			err := errors.New("proposalId required but not specified")
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		proposalID, ok := rest.ParseUint64OrReturnBadRequest(w, strProposalID)
		if !ok {
			return
		}

		cliCtx, ok = rest.ParseQueryHeightOrReturnBadRequest(w, cliCtx, r)
		if !ok {
			return
		}

		params := types.NewQueryProposalParams(proposalID)

		bz, err := cliCtx.Codec.MarshalJSON(params)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusBadRequest, err.Error())
			return
		}

		res, height, err := cliCtx.QueryWithData("custom/gov/tally", bz)
		if err != nil {
			rest.WriteErrorResponse(w, http.StatusInternalServerError, err.Error())
			return
		}

		cliCtx = cliCtx.WithHeight(height)
		rest.PostProcessResponse(w, cliCtx, res)
	}
}