/* @flow */
import TrezorConnect from 'trezor-connect';
import BigNumber from 'bignumber.js';
import * as SEND from 'actions/constants/send';
import { findDevice, getPendingAmount } from 'reducers/utils';
import { toDecimalAmount } from 'utils/formatUtils';

import type {
    Dispatch,
    GetState,
    PayloadAction,
    PromiseAction,
    BlockchainFeeLevel,
} from 'flowtype';
import type { State, FeeLevel } from 'reducers/SendFormRippleReducer';

import AddressValidator from 'wallet-address-validator';
// general regular expressions
const ABS_RE = new RegExp('^[0-9]+$');
const NUMBER_RE: RegExp = new RegExp('^(0|0\\.([0-9]+)?|[1-9][0-9]*\\.?([0-9]+)?|\\.[0-9]+)$');
const XRP_6_RE = new RegExp('^(0|0\\.([0-9]{0,6})?|[1-9][0-9]*\\.?([0-9]{0,6})?|\\.[0-9]{0,6})$');

/*
* Called from SendFormActions.observe
* Reaction for BLOCKCHAIN.FEE_UPDATED action
*/
export const onFeeUpdated = (network: string, feeLevels: Array<BlockchainFeeLevel>): PayloadAction<void> => (dispatch: Dispatch, getState: GetState): void => {
    const state = getState().sendFormRipple;
    if (network === state.networkSymbol) return;

    if (!state.untouched) {
        // if there is a transaction draft let the user know
        // and let him update manually
        dispatch({
            type: SEND.CHANGE,
            networkType: 'ripple',
            state: {
                ...state,
                feeNeedsUpdate: true,
            },
        });
        return;
    }

    // automatically update feeLevels
    const newFeeLevels = dispatch(getFeeLevels(feeLevels));
    const selectedFeeLevel = getSelectedFeeLevel(newFeeLevels, state.selectedFeeLevel);
    dispatch({
        type: SEND.CHANGE,
        networkType: 'ripple',
        state: {
            ...state,
            feeNeedsUpdate: false,
            feeLevels: newFeeLevels,
            selectedFeeLevel,
        },
    });
};

/*
* Recalculate amount, total and fees
*/
export const validation = (prevState: State): PayloadAction<State> => (dispatch: Dispatch, getState: GetState): State => {
    // clone deep nested object
    // to avoid overrides across state history
    let state: State = JSON.parse(JSON.stringify(getState().sendFormRipple));
    // reset errors
    state.errors = {};
    state.warnings = {};
    state.infos = {};
    state = dispatch(updateCustomFeeLabel(state));
    state = dispatch(recalculateTotalAmount(state));
    state = dispatch(addressValidation(state));
    state = dispatch(addressLabel(state));
    state = dispatch(amountValidation(state));
    state = dispatch(feeValidation(state));
    state = dispatch(destinationTagValidation(state));
    if (state.touched.address && prevState.address !== state.address) {
        dispatch(addressBalanceValidation(state));
    }
    return state;
};

const recalculateTotalAmount = ($state: State): PayloadAction<State> => (dispatch: Dispatch, getState: GetState): State => {
    const {
        account,
        network,
        pending,
    } = getState().selectedAccount;
    if (!account || account.networkType !== 'ripple' || !network) return $state;

    const state = { ...$state };
    const fee = toDecimalAmount(state.selectedFeeLevel.fee, network.decimals);

    if (state.setMax) {
        const pendingAmount = getPendingAmount(pending, state.networkSymbol, false);
        const availableBalance = new BigNumber(account.balance).minus(account.reserve).minus(pendingAmount);
        state.amount = calculateMaxAmount(availableBalance, fee);
    }

    state.total = calculateTotal(state.amount, fee);
    return state;
};

const updateCustomFeeLabel = ($state: State): PayloadAction<State> => (dispatch: Dispatch, getState: GetState): State => {
    const { network } = getState().selectedAccount;
    if (!network) return $state; // flowtype fallback

    const state = { ...$state };
    if ($state.selectedFeeLevel.value === 'Custom') {
        state.selectedFeeLevel = {
            ...state.selectedFeeLevel,
            fee: state.fee,
            label: `${toDecimalAmount(state.fee, network.decimals)} ${state.networkSymbol}`,
        };
    }
    return state;
};

/*
* Address value validation
*/
const addressValidation = ($state: State): PayloadAction<State> => (dispatch: Dispatch, getState: GetState): State => {
    const state = { ...$state };
    if (!state.touched.address) return state;

    const { account, network } = getState().selectedAccount;
    if (!account || !network) return state;

    const { address } = state;

    if (address.length < 1) {
        state.errors.address = 'Address is not set';
    } else if (!AddressValidator.validate(address, 'XRP')) {
        state.errors.address = 'Address is not valid';
    } else if (address.toLowerCase() === account.descriptor.toLowerCase()) {
        state.errors.address = 'Cannot send to myself';
    }
    return state;
};

/*
* Address balance validation
* Fetch data from trezor-connect and set minimum required amount in reducer
*/
const addressBalanceValidation = ($state: State): PromiseAction<void> => async (dispatch: Dispatch, getState: GetState): Promise<void> => {
    const { network } = getState().selectedAccount;
    if (!network) return;

    let minAmount: string = '0';
    const response = await TrezorConnect.rippleGetAccountInfo({
        account: {
            descriptor: $state.address,
        },
        coin: network.shortcut,
    });
    if (response.success) {
        const empty = response.payload.sequence <= 0 && response.payload.balance === '0';
        if (empty) {
            minAmount = toDecimalAmount(response.payload.reserve, network.decimals);
        }
    }

    // TODO: consider checking local (known) accounts reserve instead of async fetching

    // a2 (not empty): rJX2KwzaLJDyFhhtXKi3htaLfaUH2tptEX
    // a4 (empty): r9skfe7kZkvqss7oMB3tuj4a59PXD5wRa2

    dispatch({
        type: SEND.CHANGE,
        networkType: 'ripple',
        state: {
            ...getState().sendFormRipple,
            minAmount,
        },
    });
};

/*
* Address label assignation
*/
const addressLabel = ($state: State): PayloadAction<State> => (dispatch: Dispatch, getState: GetState): State => {
    const state = { ...$state };
    if (!state.touched.address || state.errors.address) return state;

    const {
        account,
        network,
    } = getState().selectedAccount;
    if (!account || !network) return state;
    const { address } = state;

    const savedAccounts = getState().accounts.filter(a => a.descriptor.toLowerCase() === address.toLowerCase());
    if (savedAccounts.length > 0) {
        // check if found account belongs to this network
        const currentNetworkAccount = savedAccounts.find(a => a.network === network.shortcut);
        if (currentNetworkAccount) {
            const device = findDevice(getState().devices, currentNetworkAccount.deviceID, currentNetworkAccount.deviceState);
            if (device) {
                state.infos.address = `${device.instanceLabel} Account #${(currentNetworkAccount.index + 1)}`;
            }
        } else {
            // corner-case: the same derivation path is used on different networks
            const otherNetworkAccount = savedAccounts[0];
            const device = findDevice(getState().devices, otherNetworkAccount.deviceID, otherNetworkAccount.deviceState);
            const { networks } = getState().localStorage.config;
            const otherNetwork = networks.find(c => c.shortcut === otherNetworkAccount.network);
            if (device && otherNetwork) {
                state.warnings.address = `Looks like it's ${device.instanceLabel} Account #${(otherNetworkAccount.index + 1)} address of ${otherNetwork.name} network`;
            }
        }
    }

    return state;
};

/*
* Amount value validation
*/
const amountValidation = ($state: State): PayloadAction<State> => (dispatch: Dispatch, getState: GetState): State => {
    const state = { ...$state };
    if (!state.touched.amount) return state;

    const {
        account,
        pending,
    } = getState().selectedAccount;
    if (!account || account.networkType !== 'ripple') return state;

    const { amount } = state;
    if (amount.length < 1) {
        state.errors.amount = 'Amount is not set';
    } else if (amount.length > 0 && !amount.match(NUMBER_RE)) {
        state.errors.amount = 'Amount is not a number';
    } else {
        const pendingAmount: BigNumber = getPendingAmount(pending, state.networkSymbol);
        if (!state.amount.match(XRP_6_RE)) {
            state.errors.amount = 'Maximum 6 decimals allowed';
        } else if (new BigNumber(state.total).isGreaterThan(new BigNumber(account.balance).minus(pendingAmount))) {
            state.errors.amount = 'Not enough funds';
        }
    }

    if (!state.errors.amount && new BigNumber(account.balance).minus(state.total).lt(account.reserve)) {
        state.errors.amount = `Not enough funds. Reserved amount for this account is ${account.reserve} ${state.networkSymbol}`;
    }

    if (!state.errors.amount && new BigNumber(state.amount).lt(state.minAmount)) {
        state.errors.amount = `Amount is too low. Minimum amount for creating a new account is ${state.minAmount} ${state.networkSymbol}`;
    }

    return state;
};

/*
* Fee value validation
*/
export const feeValidation = ($state: State): PayloadAction<State> => (dispatch: Dispatch, getState: GetState): State => {
    const state = { ...$state };
    if (!state.touched.fee) return state;

    const {
        network,
    } = getState().selectedAccount;
    if (!network) return state;

    const { fee } = state;
    if (fee.length < 1) {
        state.errors.fee = 'Fee is not set';
    } else if (fee.length > 0 && !fee.match(ABS_RE)) {
        state.errors.fee = 'Fee must be an absolute number';
    } else {
        const gl: BigNumber = new BigNumber(fee);
        if (gl.isLessThan(network.fee.minFee)) {
            state.errors.fee = 'Fee is below recommended';
        } else if (gl.isGreaterThan(network.fee.maxFee)) {
            state.errors.fee = 'Fee is above recommended';
        }
    }
    return state;
};
/*
* Destination Tag value validation
*/
export const destinationTagValidation = ($state: State): PayloadAction<State> => (): State => {
    const state = { ...$state };
    if (!state.touched.destinationTag) return state;

    const { destinationTag } = state;
    if (destinationTag.length > 0 && !destinationTag.match(ABS_RE)) {
        state.errors.destinationTag = 'Destination tag must be an absolute number';
    }
    return state;
};


/*
* UTILITIES
*/

const calculateTotal = (amount: string, fee: string): string => {
    try {
        const bAmount = new BigNumber(amount);
        // BigNumber() returns NaN on non-numeric string
        if (bAmount.isNaN()) {
            throw new Error('Amount is not a number');
        }
        return bAmount.plus(fee).toFixed();
    } catch (error) {
        return '0';
    }
};

const calculateMaxAmount = (balance: BigNumber, fee: string): string => {
    try {
        // TODO - minus pendings
        const max = balance.minus(fee);
        if (max.isLessThan(0)) return '0';
        return max.toFixed();
    } catch (error) {
        return '0';
    }
};

// Generate FeeLevel dataset for "fee" select
export const getFeeLevels = (feeLevels: Array<BlockchainFeeLevel>, selected?: FeeLevel): PayloadAction<Array<FeeLevel>> => (dispatch: Dispatch, getState: GetState): Array<FeeLevel> => {
    const { network } = getState().selectedAccount;
    if (!network) return []; // flowtype fallback

    // map BlockchainFeeLevel to SendFormReducer FeeLevel
    const levels = feeLevels.map(level => ({
        value: level.name,
        fee: level.value,
        label: `${toDecimalAmount(level.value, network.decimals)} ${network.symbol}`,
    }));

    // add "Custom" level
    const customLevel = selected && selected.value === 'Custom' ? {
        value: 'Custom',
        fee: selected.fee,
        label: `${toDecimalAmount(selected.fee, network.decimals)} ${network.symbol}`,
    } : {
        value: 'Custom',
        fee: '0',
        label: '',
    };

    return levels.concat([customLevel]);
};

export const getSelectedFeeLevel = (feeLevels: Array<FeeLevel>, selected: FeeLevel): FeeLevel => {
    const { value } = selected;
    let selectedFeeLevel: ?FeeLevel;
    selectedFeeLevel = feeLevels.find(f => f.value === value);
    if (!selectedFeeLevel) {
        // fallback to default
        selectedFeeLevel = feeLevels.find(f => f.value === 'Normal');
    }
    return selectedFeeLevel || selected;
};