package gov

import (
	"fmt"
	"strconv"

	metrics "github.com/armon/go-metrics"

	"github.com/cosmos/cosmos-sdk/telemetry"
	sdk "github.com/cosmos/cosmos-sdk/types"
	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
	"github.com/cosmos/cosmos-sdk/x/gov/keeper"
	"github.com/cosmos/cosmos-sdk/x/gov/types"
)

// NewHandler creates an sdk.Handler for all the gov type messages
func NewHandler(keeper keeper.Keeper) sdk.Handler {
	return func(ctx sdk.Context, msg sdk.Msg) (*sdk.Result, error) {
		ctx = ctx.WithEventManager(sdk.NewEventManager())

		switch msg := msg.(type) {
		case *types.MsgDeposit:
			return handleMsgDeposit(ctx, keeper, msg)

		case types.MsgSubmitProposalI:
			return handleMsgSubmitProposal(ctx, keeper, msg)

		case *types.MsgVote:
			return handleMsgVote(ctx, keeper, msg)

		default:
			return nil, sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "unrecognized %s message type: %T", types.ModuleName, msg)
		}
	}
}

func handleMsgSubmitProposal(ctx sdk.Context, keeper keeper.Keeper, msg types.MsgSubmitProposalI) (*sdk.Result, error) {
	proposal, err := keeper.SubmitProposal(ctx, msg.GetContent())
	if err != nil {
		return nil, err
	}

	defer telemetry.IncrCounter(1, types.ModuleName, "proposal")

	votingStarted, err := keeper.AddDeposit(ctx, proposal.ProposalId, msg.GetProposer(), msg.GetInitialDeposit())
	if err != nil {
		return nil, err
	}

	ctx.EventManager().EmitEvent(
		sdk.NewEvent(
			sdk.EventTypeMessage,
			sdk.NewAttribute(sdk.AttributeKeyModule, types.AttributeValueCategory),
			sdk.NewAttribute(sdk.AttributeKeySender, msg.GetProposer().String()),
		),
	)

	submitEvent := sdk.NewEvent(types.EventTypeSubmitProposal, sdk.NewAttribute(types.AttributeKeyProposalType, msg.GetContent().ProposalType()))
	if votingStarted {
		submitEvent = submitEvent.AppendAttributes(
			sdk.NewAttribute(types.AttributeKeyVotingPeriodStart, fmt.Sprintf("%d", proposal.ProposalId)),
		)
	}

	ctx.EventManager().EmitEvent(submitEvent)

	return &sdk.Result{
		Data:   types.GetProposalIDBytes(proposal.ProposalId),
		Events: ctx.EventManager().ABCIEvents(),
	}, nil
}

func handleMsgDeposit(ctx sdk.Context, keeper keeper.Keeper, msg *types.MsgDeposit) (*sdk.Result, error) {
	accAddr, err := sdk.AccAddressFromBech32(msg.Depositor)
	if err != nil {
		return nil, err
	}
	votingStarted, err := keeper.AddDeposit(ctx, msg.ProposalId, accAddr, msg.Amount)
	if err != nil {
		return nil, err
	}

	defer telemetry.IncrCounterWithLabels(
		[]string{types.ModuleName, "deposit"},
		1,
		[]metrics.Label{
			telemetry.NewLabel("proposal_id", strconv.Itoa(int(msg.ProposalId))),
		},
	)

	ctx.EventManager().EmitEvent(
		sdk.NewEvent(
			sdk.EventTypeMessage,
			sdk.NewAttribute(sdk.AttributeKeyModule, types.AttributeValueCategory),
			sdk.NewAttribute(sdk.AttributeKeySender, msg.Depositor),
		),
	)

	if votingStarted {
		ctx.EventManager().EmitEvent(
			sdk.NewEvent(
				types.EventTypeProposalDeposit,
				sdk.NewAttribute(types.AttributeKeyVotingPeriodStart, fmt.Sprintf("%d", msg.ProposalId)),
			),
		)
	}

	return &sdk.Result{Events: ctx.EventManager().ABCIEvents()}, nil
}

func handleMsgVote(ctx sdk.Context, keeper keeper.Keeper, msg *types.MsgVote) (*sdk.Result, error) {
	accAddr, accErr := sdk.AccAddressFromBech32(msg.Voter)
	if accErr != nil {
		return nil, accErr
	}
	err := keeper.AddVote(ctx, msg.ProposalId, accAddr, msg.Option)
	if err != nil {
		return nil, err
	}

	defer telemetry.IncrCounterWithLabels(
		[]string{types.ModuleName, "vote"},
		1,
		[]metrics.Label{
			telemetry.NewLabel("proposal_id", strconv.Itoa(int(msg.ProposalId))),
		},
	)

	ctx.EventManager().EmitEvent(
		sdk.NewEvent(
			sdk.EventTypeMessage,
			sdk.NewAttribute(sdk.AttributeKeyModule, types.AttributeValueCategory),
			sdk.NewAttribute(sdk.AttributeKeySender, msg.Voter),
		),
	)

	return &sdk.Result{Events: ctx.EventManager().ABCIEvents()}, nil
}