package keeper

import (
	"fmt"
	"strings"

	errorsmod "cosmossdk.io/errors"

	sdk "git.cw.tr/mukan-network/mukan-sdk/types"

	icatypes "git.cw.tr/mukan-network/mukan-ibc/modules/apps/27-interchain-accounts/types"
	connectiontypes "git.cw.tr/mukan-network/mukan-ibc/modules/core/03-connection/types"
	channeltypes "git.cw.tr/mukan-network/mukan-ibc/modules/core/04-channel/types"
)

// OnChanOpenInit performs basic validation of channel initialization.
// The counterparty port identifier must be the host chain representation as defined in the types package,
// the channel version must be equal to the version in the types package,
// there must not be an active channel for the specified port identifier.
func (k Keeper) OnChanOpenInit(
	ctx sdk.Context,
	order channeltypes.Order,
	connectionHops []string,
	portID string,
	channelID string,
	counterparty channeltypes.Counterparty,
	version string,
) (string, error) {
	if !strings.HasPrefix(portID, icatypes.ControllerPortPrefix) {
		return "", errorsmod.Wrapf(icatypes.ErrInvalidControllerPort, "expected %s{owner-account-address}, got %s", icatypes.ControllerPortPrefix, portID)
	}

	if counterparty.PortId != icatypes.HostPortID {
		return "", errorsmod.Wrapf(icatypes.ErrInvalidHostPort, "expected %s, got %s", icatypes.HostPortID, counterparty.PortId)
	}

	var (
		err      error
		metadata icatypes.Metadata
	)
	if strings.TrimSpace(version) == "" {
		connection, err := k.channelKeeper.GetConnection(ctx, connectionHops[0])
		if err != nil {
			return "", err
		}

		metadata = icatypes.NewDefaultMetadata(connectionHops[0], connection.Counterparty.ConnectionId)
	} else {
		metadata, err = icatypes.MetadataFromVersion(version)
		if err != nil {
			return "", err
		}
	}

	if err := icatypes.ValidateControllerMetadata(ctx, k.channelKeeper, connectionHops, metadata); err != nil {
		return "", err
	}

	activeChannelID, found := k.GetActiveChannelID(ctx, connectionHops[0], portID)
	if found {
		channel, found := k.channelKeeper.GetChannel(ctx, portID, activeChannelID)
		if !found {
			panic(fmt.Errorf("active channel mapping set for %s but channel does not exist in channel store", activeChannelID))
		}

		if channel.State != channeltypes.CLOSED {
			return "", errorsmod.Wrapf(icatypes.ErrActiveChannelAlreadySet, "existing active channel %s for portID %s must be %s", activeChannelID, portID, channeltypes.CLOSED)
		}

		if channel.Ordering != order {
			return "", errorsmod.Wrapf(channeltypes.ErrInvalidChannelOrdering, "order cannot change when reopening a channel expected %s, got %s", channel.Ordering, order)
		}

		appVersion, found := k.GetAppVersion(ctx, portID, activeChannelID)
		if !found {
			panic(fmt.Errorf("active channel mapping set for %s, but channel does not exist in channel store", activeChannelID))
		}

		if !icatypes.IsPreviousMetadataEqual(appVersion, metadata) {
			return "", errorsmod.Wrap(icatypes.ErrInvalidVersion, "previous active channel metadata does not match provided version")
		}
	}

	return string(icatypes.ModuleCdc.MustMarshalJSON(&metadata)), nil
}

// OnChanOpenAck sets the active channel for the interchain account/owner pair
// and stores the associated interchain account address in state keyed by it's corresponding port identifier
func (k Keeper) OnChanOpenAck(
	ctx sdk.Context,
	portID,
	channelID string,
	counterpartyVersion string,
) error {
	if portID == icatypes.HostPortID {
		return errorsmod.Wrapf(icatypes.ErrInvalidControllerPort, "portID cannot be host chain port ID: %s", icatypes.HostPortID)
	}

	if !strings.HasPrefix(portID, icatypes.ControllerPortPrefix) {
		return errorsmod.Wrapf(icatypes.ErrInvalidControllerPort, "expected %s{owner-account-address}, got %s", icatypes.ControllerPortPrefix, portID)
	}

	metadata, err := icatypes.MetadataFromVersion(counterpartyVersion)
	if err != nil {
		return err
	}
	if activeChannelID, found := k.GetOpenActiveChannel(ctx, metadata.ControllerConnectionId, portID); found {
		return errorsmod.Wrapf(icatypes.ErrActiveChannelAlreadySet, "existing active channel %s for portID %s", activeChannelID, portID)
	}

	channel, found := k.channelKeeper.GetChannel(ctx, portID, channelID)
	if !found {
		return errorsmod.Wrapf(channeltypes.ErrChannelNotFound, "failed to retrieve channel %s on port %s", channelID, portID)
	}

	if err := icatypes.ValidateControllerMetadata(ctx, k.channelKeeper, channel.ConnectionHops, metadata); err != nil {
		return err
	}

	if strings.TrimSpace(metadata.Address) == "" {
		return errorsmod.Wrap(icatypes.ErrInvalidAccountAddress, "interchain account address cannot be empty")
	}

	k.SetActiveChannelID(ctx, metadata.ControllerConnectionId, portID, channelID)
	k.SetInterchainAccountAddress(ctx, metadata.ControllerConnectionId, portID, metadata.Address)

	return nil
}

// OnChanCloseConfirm removes the active channel stored in state
func (Keeper) OnChanCloseConfirm(
	ctx sdk.Context,
	portID,
	channelID string,
) error {
	return nil
}

// OnChanUpgradeInit performs the upgrade init step of the channel upgrade handshake.
// The upgrade init callback must verify the proposed changes to the order, connectionHops, and version.
// Within the version we have the tx type, encoding, interchain account address, host/controller connectionID's
// and the ICS27 protocol version.
//
// The following may be changed:
// - tx type (must be supported)
// - encoding (must be supported)
// - order
//
// The following may not be changed:
// - connectionHops (and subsequently host/controller connectionIDs)
// - interchain account address
// - ICS27 protocol version
func (k Keeper) OnChanUpgradeInit(ctx sdk.Context, portID, channelID string, proposedOrder channeltypes.Order, proposedConnectionHops []string, proposedversion string) (string, error) {
	// verify connection hops has not changed
	connectionID, err := k.GetConnectionID(ctx, portID, channelID)
	if err != nil {
		return "", err
	}

	if len(proposedConnectionHops) != 1 || proposedConnectionHops[0] != connectionID {
		return "", errorsmod.Wrapf(channeltypes.ErrInvalidUpgrade, "expected connection hops %s, got %s", []string{connectionID}, proposedConnectionHops)
	}

	// verify proposed version only modifies tx type or encoding
	if strings.TrimSpace(proposedversion) == "" {
		return "", errorsmod.Wrap(icatypes.ErrInvalidVersion, "version cannot be empty")
	}

	proposedMetadata, err := icatypes.MetadataFromVersion(proposedversion)
	if err != nil {
		return "", err
	}

	currentMetadata, err := k.getAppMetadata(ctx, portID, channelID)
	if err != nil {
		return "", err
	}

	// ValidateControllerMetadata will ensure the ICS27 protocol version has not changed and that the
	// tx type and encoding are supported
	if err := icatypes.ValidateControllerMetadata(ctx, k.channelKeeper, proposedConnectionHops, proposedMetadata); err != nil {
		return "", errorsmod.Wrap(err, "invalid upgrade metadata")
	}

	// the interchain account address on the host chain
	// must remain the same after the upgrade.
	if currentMetadata.Address != proposedMetadata.Address {
		return "", errorsmod.Wrap(icatypes.ErrInvalidAccountAddress, "interchain account address cannot be changed")
	}

	if currentMetadata.ControllerConnectionId != proposedMetadata.ControllerConnectionId {
		return "", errorsmod.Wrap(connectiontypes.ErrInvalidConnection, "proposed controller connection ID must not change")
	}

	if currentMetadata.HostConnectionId != proposedMetadata.HostConnectionId {
		return "", errorsmod.Wrap(connectiontypes.ErrInvalidConnection, "proposed host connection ID must not change")
	}

	return proposedversion, nil
}

// OnChanUpgradeAck implements the ack setup of the channel upgrade handshake.
// The upgrade ack callback must verify the proposed changes to the channel version.
// Within the channel version we have the tx type, encoding, interchain account address, host/controller connectionID's
// and the ICS27 protocol version.
//
// The following may be changed:
// - tx type (must be supported)
// - encoding (must be supported)
//
// The following may not be changed:
// - controller connectionID
// - host connectionID
// - interchain account address
// - ICS27 protocol version
func (k Keeper) OnChanUpgradeAck(ctx sdk.Context, portID, channelID, counterpartyVersion string) error {
	if strings.TrimSpace(counterpartyVersion) == "" {
		return errorsmod.Wrap(channeltypes.ErrInvalidChannelVersion, "counterparty version cannot be empty")
	}

	proposedMetadata, err := icatypes.MetadataFromVersion(counterpartyVersion)
	if err != nil {
		return err
	}

	currentMetadata, err := k.getAppMetadata(ctx, portID, channelID)
	if err != nil {
		return err
	}

	channel, found := k.channelKeeper.GetChannel(ctx, portID, channelID)
	if !found {
		return errorsmod.Wrapf(channeltypes.ErrChannelNotFound, "failed to retrieve channel %s on port %s", channelID, portID)
	}

	// ValidateControllerMetadata will ensure the ICS27 protocol version has not changed and that the
	// tx type and encoding are supported. Note, we pass in the current channel connection hops. The upgrade init
	// step will verify that the proposed connection hops will not change.
	if err := icatypes.ValidateControllerMetadata(ctx, k.channelKeeper, channel.ConnectionHops, proposedMetadata); err != nil {
		return errorsmod.Wrap(err, "invalid upgrade metadata")
	}

	// the interchain account address on the host chain
	// must remain the same after the upgrade.
	if currentMetadata.Address != proposedMetadata.Address {
		return errorsmod.Wrap(icatypes.ErrInvalidAccountAddress, "address cannot be changed")
	}

	if currentMetadata.ControllerConnectionId != proposedMetadata.ControllerConnectionId {
		return errorsmod.Wrap(connectiontypes.ErrInvalidConnection, "proposed controller connection ID must not change")
	}

	if currentMetadata.HostConnectionId != proposedMetadata.HostConnectionId {
		return errorsmod.Wrap(connectiontypes.ErrInvalidConnection, "proposed host connection ID must not change")
	}

	return nil
}