package keeper

import (
	"context"
	"fmt"

	"cosmossdk.io/core/address"
	"cosmossdk.io/core/appmodule"
	"cosmossdk.io/core/event"
	errorsmod "cosmossdk.io/errors"
	"cosmossdk.io/math"
	"cosmossdk.io/x/bank/types"

	"github.com/cosmos/cosmos-sdk/codec"
	sdk "github.com/cosmos/cosmos-sdk/types"
	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
	"github.com/cosmos/cosmos-sdk/types/query"
	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
)

var _ Keeper = (*BaseKeeper)(nil)

// Keeper defines a module interface that facilitates the transfer of coins
// between accounts.
type Keeper interface {
	SendKeeper
	WithMintCoinsRestriction(types.MintingRestrictionFn) BaseKeeper

	InitGenesis(context.Context, *types.GenesisState) error
	ExportGenesis(context.Context) (*types.GenesisState, error)

	GetSupply(ctx context.Context, denom string) sdk.Coin
	HasSupply(ctx context.Context, denom string) bool
	GetPaginatedTotalSupply(ctx context.Context, pagination *query.PageRequest) (sdk.Coins, *query.PageResponse, error)
	IterateTotalSupply(ctx context.Context, cb func(sdk.Coin) bool)
	GetDenomMetaData(ctx context.Context, denom string) (types.Metadata, bool)
	HasDenomMetaData(ctx context.Context, denom string) bool
	SetDenomMetaData(ctx context.Context, denomMetaData types.Metadata)
	GetAllDenomMetaData(ctx context.Context) []types.Metadata
	IterateAllDenomMetaData(ctx context.Context, cb func(types.Metadata) bool)

	SendCoinsFromModuleToAccount(ctx context.Context, senderModule string, recipientAddr sdk.AccAddress, amt sdk.Coins) error
	SendCoinsFromModuleToModule(ctx context.Context, senderModule, recipientModule string, amt sdk.Coins) error
	SendCoinsFromAccountToModule(ctx context.Context, senderAddr sdk.AccAddress, recipientModule string, amt sdk.Coins) error
	DelegateCoinsFromAccountToModule(ctx context.Context, senderAddr sdk.AccAddress, recipientModule string, amt sdk.Coins) error
	UndelegateCoinsFromModuleToAccount(ctx context.Context, senderModule string, recipientAddr sdk.AccAddress, amt sdk.Coins) error
	MintCoins(ctx context.Context, moduleName string, amt sdk.Coins) error
	BurnCoins(ctx context.Context, address []byte, amt sdk.Coins) error

	DelegateCoins(ctx context.Context, delegatorAddr, moduleAccAddr sdk.AccAddress, amt sdk.Coins) error
	UndelegateCoins(ctx context.Context, moduleAccAddr, delegatorAddr sdk.AccAddress, amt sdk.Coins) error

	types.QueryServer
}

// BaseKeeper manages transfers between accounts. It implements the Keeper interface.
type BaseKeeper struct {
	appmodule.Environment
	BaseSendKeeper

	ak                     types.AccountKeeper
	cdc                    codec.BinaryCodec
	mintCoinsRestrictionFn types.MintingRestrictionFn
	addrCdc                address.Codec
}

// GetPaginatedTotalSupply queries for the supply, ignoring 0 coins, with a given pagination
func (k BaseKeeper) GetPaginatedTotalSupply(ctx context.Context, pagination *query.PageRequest) (sdk.Coins, *query.PageResponse, error) {
	coins, pageResp, err := query.CollectionPaginate(ctx, k.Supply, pagination, func(key string, value math.Int) (sdk.Coin, error) {
		return sdk.NewCoin(key, value), nil
	})
	if err != nil {
		return nil, nil, err
	}

	return coins, pageResp, nil
}

// NewBaseKeeper returns a new BaseKeeper object with a given codec, dedicated
// store key, an AccountKeeper implementation, and a parameter Subspace used to
// store and fetch module parameters. The BaseKeeper also accepts a
// blocklist map. This blocklist describes the set of addresses that are not allowed
// to receive funds through direct and explicit actions, for example, by using a MsgSend or
// by using a SendCoinsFromModuleToAccount execution.
func NewBaseKeeper(
	env appmodule.Environment,
	cdc codec.BinaryCodec,
	ak types.AccountKeeper,
	blockedAddrs map[string]bool,
	authority string,
) BaseKeeper {
	addrCdc := ak.AddressCodec()
	if _, err := addrCdc.StringToBytes(authority); err != nil {
		panic(fmt.Errorf("invalid bank authority address: %w", err))
	}

	return BaseKeeper{
		Environment:            env,
		BaseSendKeeper:         NewBaseSendKeeper(env, cdc, ak, blockedAddrs, authority),
		ak:                     ak,
		cdc:                    cdc,
		mintCoinsRestrictionFn: types.NoOpMintingRestrictionFn,
		addrCdc:                addrCdc,
	}
}

// WithMintCoinsRestriction restricts the bank Keeper used within a specific module to
// have restricted permissions on minting via function passed in parameter.
// Previous restriction functions can be nested as such:
//
//	bankKeeper.WithMintCoinsRestriction(restriction1).WithMintCoinsRestriction(restriction2)
func (k BaseKeeper) WithMintCoinsRestriction(check types.MintingRestrictionFn) BaseKeeper {
	k.mintCoinsRestrictionFn = check.Then(k.mintCoinsRestrictionFn)
	return k
}

// DelegateCoins performs delegation by deducting amt coins from an account with
// address addr. For vesting accounts, delegations amounts are tracked for both
// vesting and vested coins. The coins are then transferred from the delegator
// address to a ModuleAccount address. If any of the delegation amounts are negative,
// an error is returned.
func (k BaseKeeper) DelegateCoins(ctx context.Context, delegatorAddr, moduleAccAddr sdk.AccAddress, amt sdk.Coins) error {
	moduleAcc := k.ak.GetAccount(ctx, moduleAccAddr)
	if moduleAcc == nil {
		return errorsmod.Wrapf(sdkerrors.ErrUnknownAddress, "module account %s does not exist", moduleAccAddr)
	}

	if !amt.IsValid() {
		return errorsmod.Wrap(sdkerrors.ErrInvalidCoins, amt.String())
	}

	balances := sdk.NewCoins()

	for _, coin := range amt {
		balance := k.GetBalance(ctx, delegatorAddr, coin.GetDenom())
		if balance.IsLT(coin) {
			return errorsmod.Wrapf(
				sdkerrors.ErrInsufficientFunds, "failed to delegate; %s is smaller than %s", balance, amt,
			)
		}

		balances = balances.Add(balance)
		err := k.setBalance(ctx, delegatorAddr, balance.Sub(coin))
		if err != nil {
			return err
		}
	}

	if err := k.trackDelegation(ctx, delegatorAddr, balances, amt); err != nil {
		return errorsmod.Wrap(err, "failed to track delegation")
	}
	// emit coin spent event
	delAddrStr, err := k.addrCdc.BytesToString(delegatorAddr)
	if err != nil {
		return err
	}
	if err = k.EventService.EventManager(ctx).EmitKV(
		types.EventTypeCoinSpent,
		event.NewAttribute(types.AttributeKeySpender, delAddrStr),
		event.NewAttribute(sdk.AttributeKeyAmount, amt.String()),
	); err != nil {
		return err
	}

	return k.addCoins(ctx, moduleAccAddr, amt)
}

// UndelegateCoins performs undelegation by crediting amt coins to an account with
// address addr. For vesting accounts, undelegation amounts are tracked for both
// vesting and vested coins. The coins are then transferred from a ModuleAccount
// address to the delegator address. If any of the undelegation amounts are
// negative, an error is returned.
func (k BaseKeeper) UndelegateCoins(ctx context.Context, moduleAccAddr, delegatorAddr sdk.AccAddress, amt sdk.Coins) error {
	moduleAcc := k.ak.GetAccount(ctx, moduleAccAddr)
	if moduleAcc == nil {
		return errorsmod.Wrapf(sdkerrors.ErrUnknownAddress, "module account %s does not exist", moduleAccAddr)
	}

	if !amt.IsValid() {
		return errorsmod.Wrap(sdkerrors.ErrInvalidCoins, amt.String())
	}

	if err := k.subUnlockedCoins(ctx, moduleAccAddr, amt); err != nil {
		return err
	}

	if err := k.trackUndelegation(ctx, delegatorAddr, amt); err != nil {
		return errorsmod.Wrap(err, "failed to track undelegation")
	}

	return k.addCoins(ctx, delegatorAddr, amt)
}

// GetSupply retrieves the Supply from store
func (k BaseKeeper) GetSupply(ctx context.Context, denom string) sdk.Coin {
	amt, err := k.Supply.Get(ctx, denom)
	if err != nil {
		return sdk.NewCoin(denom, math.ZeroInt())
	}
	return sdk.NewCoin(denom, amt)
}

// HasSupply checks if the supply coin exists in store.
func (k BaseKeeper) HasSupply(ctx context.Context, denom string) bool {
	has, err := k.Supply.Has(ctx, denom)
	return has && err == nil
}

// GetDenomMetaData retrieves the denomination metadata. returns the metadata and true if the denom exists,
// false otherwise.
func (k BaseKeeper) GetDenomMetaData(ctx context.Context, denom string) (types.Metadata, bool) {
	m, err := k.BaseViewKeeper.DenomMetadata.Get(ctx, denom)
	return m, err == nil
}

// HasDenomMetaData checks if the denomination metadata exists in store.
func (k BaseKeeper) HasDenomMetaData(ctx context.Context, denom string) bool {
	has, err := k.BaseViewKeeper.DenomMetadata.Has(ctx, denom)
	return has && err == nil
}

// GetAllDenomMetaData retrieves all denominations metadata
func (k BaseKeeper) GetAllDenomMetaData(ctx context.Context) []types.Metadata {
	denomMetaData := make([]types.Metadata, 0)
	k.IterateAllDenomMetaData(ctx, func(metadata types.Metadata) bool {
		denomMetaData = append(denomMetaData, metadata)
		return false
	})

	return denomMetaData
}

// IterateAllDenomMetaData iterates over all the denominations metadata and
// provides the metadata to a callback. If true is returned from the
// callback, iteration is halted.
func (k BaseKeeper) IterateAllDenomMetaData(ctx context.Context, cb func(types.Metadata) bool) {
	err := k.BaseViewKeeper.DenomMetadata.Walk(ctx, nil, func(_ string, metadata types.Metadata) (stop bool, err error) {
		return cb(metadata), nil
	})
	if err != nil {
		panic(err)
	}
}

// SetDenomMetaData sets the denominations metadata
func (k BaseKeeper) SetDenomMetaData(ctx context.Context, denomMetaData types.Metadata) {
	_ = k.BaseViewKeeper.DenomMetadata.Set(ctx, denomMetaData.Base, denomMetaData)
}

// SendCoinsFromModuleToAccount transfers coins from a ModuleAccount to an AccAddress.
// An error is returned if the module account does not exist or if
// the recipient address is black-listed or if sending the tokens fails.
func (k BaseKeeper) SendCoinsFromModuleToAccount(
	ctx context.Context, senderModule string, recipientAddr sdk.AccAddress, amt sdk.Coins,
) error {
	senderAddr := k.ak.GetModuleAddress(senderModule)
	if senderAddr == nil {
		return errorsmod.Wrapf(sdkerrors.ErrUnknownAddress, "module account %s does not exist", senderModule)
	}

	if k.BlockedAddr(recipientAddr) {
		return errorsmod.Wrapf(sdkerrors.ErrUnauthorized, "%s is not allowed to receive funds", recipientAddr)
	}

	return k.SendCoins(ctx, senderAddr, recipientAddr, amt)
}

// SendCoinsFromModuleToModule transfers coins from a ModuleAccount to another.
// An error is returned if either module accounts does not exist.
func (k BaseKeeper) SendCoinsFromModuleToModule(
	ctx context.Context, senderModule, recipientModule string, amt sdk.Coins,
) error {
	senderAddr := k.ak.GetModuleAddress(senderModule)
	if senderAddr == nil {
		return errorsmod.Wrapf(sdkerrors.ErrUnknownAddress, "module account %s does not exist", senderModule)
	}

	recipientAcc := k.ak.GetModuleAccount(ctx, recipientModule)
	if recipientAcc == nil {
		return errorsmod.Wrapf(sdkerrors.ErrUnknownAddress, "module account %s does not exist", recipientModule)
	}

	return k.SendCoins(ctx, senderAddr, recipientAcc.GetAddress(), amt)
}

// SendCoinsFromAccountToModule transfers coins from an AccAddress to a ModuleAccount.
// An error is returned if the module account does not exist.
func (k BaseKeeper) SendCoinsFromAccountToModule(
	ctx context.Context, senderAddr sdk.AccAddress, recipientModule string, amt sdk.Coins,
) error {
	recipientAcc := k.ak.GetModuleAccount(ctx, recipientModule)
	if recipientAcc == nil {
		return errorsmod.Wrapf(sdkerrors.ErrUnknownAddress, "module account %s does not exist", recipientModule)
	}

	return k.SendCoins(ctx, senderAddr, recipientAcc.GetAddress(), amt)
}

// DelegateCoinsFromAccountToModule delegates coins and transfers them from a
// delegator account to a module account. An error is returned if the module account
// does not exist or is unauthorized.
func (k BaseKeeper) DelegateCoinsFromAccountToModule(
	ctx context.Context, senderAddr sdk.AccAddress, recipientModule string, amt sdk.Coins,
) error {
	recipientAcc := k.ak.GetModuleAccount(ctx, recipientModule)
	if recipientAcc == nil {
		return errorsmod.Wrapf(sdkerrors.ErrUnknownAddress, "module account %s does not exist", recipientModule)
	}

	if !recipientAcc.HasPermission(authtypes.Staking) {
		return errorsmod.Wrapf(sdkerrors.ErrUnauthorized, "module account %s does not have permissions to receive delegated coins", recipientModule)
	}

	return k.DelegateCoins(ctx, senderAddr, recipientAcc.GetAddress(), amt)
}

// UndelegateCoinsFromModuleToAccount undelegates the unbonding coins and transfers
// them from a module account to the delegator account. An error is returned if the
// module account does not exist or is unauthorized.
func (k BaseKeeper) UndelegateCoinsFromModuleToAccount(
	ctx context.Context, senderModule string, recipientAddr sdk.AccAddress, amt sdk.Coins,
) error {
	acc := k.ak.GetModuleAccount(ctx, senderModule)
	if acc == nil {
		return errorsmod.Wrapf(sdkerrors.ErrUnknownAddress, "module account %s does not exist", senderModule)
	}

	if !acc.HasPermission(authtypes.Staking) {
		return errorsmod.Wrapf(sdkerrors.ErrUnauthorized, "module account %s does not have permissions to undelegate coins", senderModule)
	}

	return k.UndelegateCoins(ctx, acc.GetAddress(), recipientAddr, amt)
}

// MintCoins creates new coins from thin air and adds it to the module account.
// An error is returned if the module account does not exist or is unauthorized.
func (k BaseKeeper) MintCoins(ctx context.Context, moduleName string, amounts sdk.Coins) error {
	err := k.mintCoinsRestrictionFn(ctx, amounts)
	if err != nil {
		k.Logger.Error(fmt.Sprintf("Module %q attempted to mint coins %s it doesn't have permission for, error %v", moduleName, amounts, err))
		return err
	}
	acc := k.ak.GetModuleAccount(ctx, moduleName)
	if acc == nil {
		return errorsmod.Wrapf(sdkerrors.ErrUnknownAddress, "module account %s does not exist", moduleName)
	}

	if !acc.HasPermission(authtypes.Minter) {
		return errorsmod.Wrapf(sdkerrors.ErrUnauthorized, "module account %s does not have permissions to mint tokens", moduleName)
	}

	if !amounts.IsValid() {
		return errorsmod.Wrap(sdkerrors.ErrInvalidCoins, amounts.String())
	}

	err = k.addCoins(ctx, acc.GetAddress(), amounts)
	if err != nil {
		return err
	}

	for _, amount := range amounts {
		supply := k.GetSupply(ctx, amount.GetDenom())
		supply = supply.Add(amount)
		k.setSupply(ctx, supply)
	}

	k.Logger.Debug("minted coins from module account", "amount", amounts.String(), "from", moduleName)

	addrStr, err := k.addrCdc.BytesToString(acc.GetAddress())
	if err != nil {
		return err
	}

	// emit mint event
	return k.EventService.EventManager(ctx).EmitKV(
		types.EventTypeCoinMint,
		event.NewAttribute(types.AttributeKeyMinter, addrStr),
		event.NewAttribute(sdk.AttributeKeyAmount, amounts.String()),
	)
}

// BurnCoins burns coins deletes coins from the balance of an account.
// An error is returned if the module account does not exist or is unauthorized.
func (k BaseKeeper) BurnCoins(ctx context.Context, address []byte, amounts sdk.Coins) error {
	acc := k.ak.GetAccount(ctx, address)
	if acc == nil {
		return errorsmod.Wrapf(sdkerrors.ErrUnknownAddress, "account %x does not exist", address)
	}

	if macc, ok := acc.(sdk.ModuleAccountI); ok {
		if !macc.HasPermission(authtypes.Burner) {
			return errorsmod.Wrapf(sdkerrors.ErrUnauthorized, "account %x does not have permissions to burn tokens", address)
		}
	}
	if !amounts.IsValid() {
		return errorsmod.Wrap(sdkerrors.ErrInvalidCoins, amounts.String())
	}

	err := k.subUnlockedCoins(ctx, acc.GetAddress(), amounts)
	if err != nil {
		return err
	}

	for _, amount := range amounts {
		supply := k.GetSupply(ctx, amount.GetDenom())
		supply = supply.Sub(amount)
		k.setSupply(ctx, supply)
	}

	addrStr, err := k.addrCdc.BytesToString(acc.GetAddress())
	if err != nil {
		return err
	}

	k.Logger.Debug("burned tokens from account", "amount", amounts.String(), "from", addrStr)

	// emit burn event
	return k.EventService.EventManager(ctx).EmitKV(
		types.EventTypeCoinBurn,
		event.NewAttribute(types.AttributeKeyBurner, addrStr),
		event.NewAttribute(sdk.AttributeKeyAmount, amounts.String()),
	)
}

// setSupply sets the supply for the given coin
func (k BaseKeeper) setSupply(ctx context.Context, coin sdk.Coin) {
	// Bank invariants and IBC requires to remove zero coins.
	if coin.IsZero() {
		_ = k.Supply.Remove(ctx, coin.Denom)
	} else {
		_ = k.Supply.Set(ctx, coin.Denom, coin.Amount)
	}
}

// trackDelegation tracks the delegation of the given account if it is a vesting account
func (k BaseKeeper) trackDelegation(ctx context.Context, addr sdk.AccAddress, balance, amt sdk.Coins) error {
	acc := k.ak.GetAccount(ctx, addr)
	if acc == nil {
		// check if it's an x/accounts smart account
		if k.ak.HasAccount(ctx, addr) {
			return nil
		}
		return errorsmod.Wrapf(sdkerrors.ErrUnknownAddress, "account %s does not exist", addr)
	}

	vacc, ok := acc.(types.VestingAccount)
	if ok {
		// TODO: return error on account.TrackDelegation
		vacc.TrackDelegation(k.HeaderService.HeaderInfo(ctx).Time, balance, amt)
		k.ak.SetAccount(ctx, acc)
	}

	return nil
}

// trackUndelegation tracks undelegation of the given account if it is a vesting account
func (k BaseKeeper) trackUndelegation(ctx context.Context, addr sdk.AccAddress, amt sdk.Coins) error {
	acc := k.ak.GetAccount(ctx, addr)
	if acc == nil {
		// check if it's an x/accounts smart account
		if k.ak.HasAccount(ctx, addr) {
			return nil
		}
		return errorsmod.Wrapf(sdkerrors.ErrUnknownAddress, "account %s does not exist", addr)
	}

	vacc, ok := acc.(types.VestingAccount)
	if ok {
		// TODO: return error on account.TrackUndelegation
		vacc.TrackUndelegation(amt)
		k.ak.SetAccount(ctx, acc)
	}

	return nil
}

// IterateTotalSupply iterates over the total supply calling the given cb (callback) function
// with the balance of each coin.
// The iteration stops if the callback returns true.
func (k BaseViewKeeper) IterateTotalSupply(ctx context.Context, cb func(sdk.Coin) bool) {
	err := k.Supply.Walk(ctx, nil, func(s string, m math.Int) (bool, error) {
		return cb(sdk.NewCoin(s, m)), nil
	})
	if err != nil {
		panic(err)
	}
}