package bank

import (
	sdk "github.com/cosmos/cosmos-sdk/types"
)

// name to identify transaction routes
const RouterKey = "bank"

// MsgSend - high level transaction of the coin module
type MsgSend struct {
	Inputs  []Input  `json:"inputs"`
	Outputs []Output `json:"outputs"`
}

var _ sdk.Msg = MsgSend{}

// NewMsgSend - construct arbitrary multi-in, multi-out send msg.
func NewMsgSend(in []Input, out []Output) MsgSend {
	return MsgSend{Inputs: in, Outputs: out}
}

// Implements Msg.
// nolint
func (msg MsgSend) Route() string { return RouterKey }
func (msg MsgSend) Type() string  { return "send" }

// Implements Msg.
func (msg MsgSend) ValidateBasic() sdk.Error {
	// this just makes sure all the inputs and outputs are properly formatted,
	// not that they actually have the money inside
	if len(msg.Inputs) == 0 {
		return ErrNoInputs(DefaultCodespace).TraceSDK("")
	}
	if len(msg.Outputs) == 0 {
		return ErrNoOutputs(DefaultCodespace).TraceSDK("")
	}

	return ValidateInputsOutputs(msg.Inputs, msg.Outputs)
}

// Implements Msg.
func (msg MsgSend) GetSignBytes() []byte {
	bz := msgCdc.MustMarshalJSON(msg)
	return sdk.MustSortJSON(bz)
}

// Implements Msg.
func (msg MsgSend) GetSigners() []sdk.AccAddress {
	addrs := make([]sdk.AccAddress, len(msg.Inputs))
	for i, in := range msg.Inputs {
		addrs[i] = in.Address
	}
	return addrs
}

//----------------------------------------
// Input

// Transaction Input
type Input struct {
	Address sdk.AccAddress `json:"address"`
	Coins   sdk.Coins      `json:"coins"`
}

// ValidateBasic - validate transaction input
func (in Input) ValidateBasic() sdk.Error {
	if len(in.Address) == 0 {
		return sdk.ErrInvalidAddress(in.Address.String())
	}
	if !in.Coins.IsValid() {
		return sdk.ErrInvalidCoins(in.Coins.String())
	}
	if !in.Coins.IsPositive() {
		return sdk.ErrInvalidCoins(in.Coins.String())
	}
	return nil
}

// NewInput - create a transaction input, used with MsgSend
func NewInput(addr sdk.AccAddress, coins sdk.Coins) Input {
	return Input{
		Address: addr,
		Coins:   coins,
	}
}

//----------------------------------------
// Output

// Transaction Output
type Output struct {
	Address sdk.AccAddress `json:"address"`
	Coins   sdk.Coins      `json:"coins"`
}

// ValidateBasic - validate transaction output
func (out Output) ValidateBasic() sdk.Error {
	if len(out.Address) == 0 {
		return sdk.ErrInvalidAddress(out.Address.String())
	}
	if !out.Coins.IsValid() {
		return sdk.ErrInvalidCoins(out.Coins.String())
	}
	if !out.Coins.IsPositive() {
		return sdk.ErrInvalidCoins(out.Coins.String())
	}
	return nil
}

// NewOutput - create a transaction output, used with MsgSend
func NewOutput(addr sdk.AccAddress, coins sdk.Coins) Output {
	return Output{
		Address: addr,
		Coins:   coins,
	}
}

// ----------------------------------------------------------------------------
// Auxiliary

// ValidateInputsOutputs validates that each respective input and output is
// valid and that the sum of inputs is equal to the sum of outputs.
func ValidateInputsOutputs(inputs []Input, outputs []Output) sdk.Error {
	var totalIn, totalOut sdk.Coins

	for _, in := range inputs {
		if err := in.ValidateBasic(); err != nil {
			return err.TraceSDK("")
		}
		totalIn = totalIn.Plus(in.Coins)
	}

	for _, out := range outputs {
		if err := out.ValidateBasic(); err != nil {
			return err.TraceSDK("")
		}
		totalOut = totalOut.Plus(out.Coins)
	}

	// make sure inputs and outputs match
	if !totalIn.IsEqual(totalOut) {
		return sdk.ErrInvalidCoins(totalIn.String()).TraceSDK("inputs and outputs don't match")
	}

	return nil
}