from typing import TYPE_CHECKING, Optional

from PyQt5.QtCore import pyqtSignal
from PyQt5.QtWidgets import QLabel, QVBoxLayout, QGridLayout, QPushButton

from electrum.i18n import _
from electrum.util import NotEnoughFunds, NoDynamicFeeEstimates
from electrum.lnutil import ln_dummy_address
from electrum.transaction import PartialTxOutput, PartialTransaction

from .util import (WindowModalDialog, Buttons, OkButton, CancelButton,
                   EnterButton, ColorScheme, WWLabel, read_QIcon, IconLabel)
from .amountedit import BTCAmountEdit
from .fee_slider import FeeSlider, FeeComboBox

if TYPE_CHECKING:
    from .main_window import ElectrumWindow

CANNOT_RECEIVE_WARNING = """
The requested amount is higher than what you can receive in your currently open channels.
If you continue, your funds will be locked until the remote server can find a path to pay you.
If the swap cannot be performed after 24h, you will be refunded.
Do you want to continue?
"""


class SwapDialog(WindowModalDialog):

    tx: Optional[PartialTransaction]
    update_signal = pyqtSignal()

    def __init__(self, window: 'ElectrumWindow'):
        WindowModalDialog.__init__(self, window, _('Submarine Swap'))
        self.window = window
        self.config = window.config
        self.lnworker = self.window.wallet.lnworker
        self.swap_manager = self.lnworker.swap_manager
        self.network = window.network
        self.tx = None  # for the forward-swap only
        self.is_reverse = True
        vbox = QVBoxLayout(self)
        self.description_label = WWLabel(self.get_description())
        self.send_amount_e = BTCAmountEdit(self.window.get_decimal_point)
        self.recv_amount_e = BTCAmountEdit(self.window.get_decimal_point)
        self.max_button = EnterButton(_("Max"), self.spend_max)
        self.max_button.setFixedWidth(100)
        self.max_button.setCheckable(True)
        self.toggle_button = QPushButton(u'\U000021c4')
        # send_follows is used to know whether the send amount field / receive
        # amount field should be adjusted after the fee slider was moved
        self.send_follows = False
        self.send_amount_e.follows = False
        self.recv_amount_e.follows = False
        self.toggle_button.clicked.connect(self.toggle_direction)
        # textChanged is triggered for both user and automatic action
        self.send_amount_e.textChanged.connect(self.on_send_edited)
        self.recv_amount_e.textChanged.connect(self.on_recv_edited)
        # textEdited is triggered only for user editing of the fields
        self.send_amount_e.textEdited.connect(self.uncheck_max)
        self.recv_amount_e.textEdited.connect(self.uncheck_max)
        fee_slider = FeeSlider(self.window, self.config, self.fee_slider_callback)
        fee_combo = FeeComboBox(fee_slider)
        fee_slider.update()
        self.fee_label = QLabel()
        self.server_fee_label = QLabel()
        vbox.addWidget(self.description_label)
        h = QGridLayout()
        self.send_label = IconLabel(text=_('You send')+':')
        self.recv_label = IconLabel(text=_('You receive')+':')
        h.addWidget(self.send_label, 1, 0)
        h.addWidget(self.send_amount_e, 1, 1)
        h.addWidget(self.max_button, 1, 2)
        h.addWidget(self.toggle_button, 1, 3)
        h.addWidget(self.recv_label, 2, 0)
        h.addWidget(self.recv_amount_e, 2, 1)
        h.addWidget(QLabel(_('Server fee')+':'), 4, 0)
        h.addWidget(self.server_fee_label, 4, 1, 1, 2)
        h.addWidget(QLabel(_('Mining fee')+':'), 5, 0)
        h.addWidget(self.fee_label, 5, 1, 1, 2)
        h.addWidget(fee_slider, 6, 1)
        h.addWidget(fee_combo, 6, 2)
        vbox.addLayout(h)
        vbox.addStretch(1)
        self.ok_button = OkButton(self)
        self.ok_button.setDefault(True)
        self.ok_button.setEnabled(False)
        vbox.addLayout(Buttons(CancelButton(self), self.ok_button))
        self.update_signal.connect(self.update)
        self.update()

    def fee_slider_callback(self, dyn, pos, fee_rate):
        if dyn:
            if self.config.use_mempool_fees():
                self.config.set_key('depth_level', pos, False)
            else:
                self.config.set_key('fee_level', pos, False)
        else:
            self.config.set_key('fee_per_kb', fee_rate, False)
        if self.send_follows:
            self.on_recv_edited()
        else:
            self.on_send_edited()
        self.update()

    def toggle_direction(self):
        self.is_reverse = not self.is_reverse
        self.send_amount_e.setAmount(None)
        self.recv_amount_e.setAmount(None)
        self.max_button.setChecked(False)
        self.update()

    def spend_max(self):
        if self.max_button.isChecked():
            if self.is_reverse:
                self._spend_max_reverse_swap()
            else:
                self._spend_max_forward_swap()
        else:
            self.send_amount_e.setAmount(None)
        self.update_fee()
        self.update_ok_button()

    def uncheck_max(self):
        self.max_button.setChecked(False)
        self.update()

    def _spend_max_forward_swap(self):
        self._update_tx('!')
        if self.tx:
            amount = self.tx.output_value_for_address(ln_dummy_address())
            max_swap_amt = self.swap_manager.get_max_amount()
            max_recv_amt_ln = int(self.swap_manager.num_sats_can_receive())
            max_recv_amt_oc = self.swap_manager.get_send_amount(max_recv_amt_ln, is_reverse=False) or float('inf')
            max_amt = int(min(max_swap_amt, max_recv_amt_oc))
            if amount > max_amt:
                amount = max_amt
                self._update_tx(amount)
            if self.tx:
                amount = self.tx.output_value_for_address(ln_dummy_address())
                assert amount <= max_amt
                self.send_amount_e.setAmount(amount)

    def _spend_max_reverse_swap(self):
        amount = min(self.lnworker.num_sats_can_send(), self.swap_manager.get_max_amount())
        self.send_amount_e.setAmount(amount)

    def on_send_edited(self):
        if self.send_amount_e.follows:
            return
        self.send_amount_e.setStyleSheet(ColorScheme.DEFAULT.as_stylesheet())
        send_amount = self.send_amount_e.get_amount()
        recv_amount = self.swap_manager.get_recv_amount(send_amount, is_reverse=self.is_reverse)
        if self.is_reverse and send_amount and send_amount > self.lnworker.num_sats_can_send():
            # cannot send this much on lightning
            recv_amount = None
        if (not self.is_reverse) and recv_amount and recv_amount > self.swap_manager.num_sats_can_receive():
            # cannot receive this much on lightning
            recv_amount = None
        self.recv_amount_e.follows = True
        self.recv_amount_e.setAmount(recv_amount)
        self.recv_amount_e.setStyleSheet(ColorScheme.BLUE.as_stylesheet())
        self.recv_amount_e.follows = False
        self.send_follows = False
        self._update_tx(send_amount)
        self.update_fee()
        self.update_ok_button()

    def on_recv_edited(self):
        if self.recv_amount_e.follows:
            return
        self.recv_amount_e.setStyleSheet(ColorScheme.DEFAULT.as_stylesheet())
        recv_amount = self.recv_amount_e.get_amount()
        send_amount = self.swap_manager.get_send_amount(recv_amount, is_reverse=self.is_reverse)
        if self.is_reverse and send_amount and send_amount > self.lnworker.num_sats_can_send():
            send_amount = None
        self.send_amount_e.follows = True
        self.send_amount_e.setAmount(send_amount)
        self.send_amount_e.setStyleSheet(ColorScheme.BLUE.as_stylesheet())
        self.send_amount_e.follows = False
        self.send_follows = True
        self._update_tx(send_amount)
        self.update_fee()
        self.update_ok_button()

    def update(self):
        from .util import IconLabel
        sm = self.swap_manager
        send_icon = read_QIcon("lightning.png" if self.is_reverse else "bitcoin.png")
        self.send_label.setIcon(send_icon)
        recv_icon = read_QIcon("lightning.png" if not self.is_reverse else "bitcoin.png")
        self.recv_label.setIcon(recv_icon)
        self.description_label.setText(self.get_description())
        self.description_label.repaint()  # macOS hack for #6269
        server_mining_fee = sm.lockup_fee if self.is_reverse else sm.normal_fee
        server_fee_str = '%.2f'%sm.percentage + '%  +  '  + self.window.format_amount(server_mining_fee) + ' ' + self.window.base_unit()
        self.server_fee_label.setText(server_fee_str)
        self.server_fee_label.repaint()  # macOS hack for #6269
        self.update_tx()
        self.update_fee()
        self.update_ok_button()

    def update_fee(self):
        """Updates self.fee_label. No other side-effects."""
        if self.is_reverse:
            sm = self.swap_manager
            fee = sm.get_claim_fee()
        else:
            fee = self.tx.get_fee() if self.tx else None
        fee_text = self.window.format_amount(fee) + ' ' + self.window.base_unit() if fee else ''
        self.fee_label.setText(fee_text)
        self.fee_label.repaint()  # macOS hack for #6269

    def run(self):
        if not self.network:
            self.window.show_error(_("You are offline."))
            return
        self.window.run_coroutine_from_thread(self.swap_manager.get_pairs(), lambda x: self.update_signal.emit())
        if not self.exec_():
            return
        if self.is_reverse:
            lightning_amount = self.send_amount_e.get_amount()
            onchain_amount = self.recv_amount_e.get_amount()
            if lightning_amount is None or onchain_amount is None:
                return
            coro = self.swap_manager.reverse_swap(
                lightning_amount_sat=lightning_amount,
                expected_onchain_amount_sat=onchain_amount + self.swap_manager.get_claim_fee(),
            )
            self.window.run_coroutine_from_thread(coro)
        else:
            lightning_amount = self.recv_amount_e.get_amount()
            onchain_amount = self.send_amount_e.get_amount()
            if lightning_amount is None or onchain_amount is None:
                return
            if lightning_amount > self.swap_manager.num_sats_can_receive():
                if not self.window.question(CANNOT_RECEIVE_WARNING):
                    return
            self.window.protect(self.do_normal_swap, (lightning_amount, onchain_amount))

    def update_tx(self):
        if self.is_reverse:
            return
        is_max = self.max_button.isChecked()
        if is_max:
            self._spend_max_forward_swap()
        else:
            onchain_amount = self.send_amount_e.get_amount()
            self._update_tx(onchain_amount)

    def _update_tx(self, onchain_amount):
        """Updates self.tx. No other side-effects."""
        if self.is_reverse:
            return
        if onchain_amount is None:
            self.tx = None
            return
        outputs = [PartialTxOutput.from_address_and_value(ln_dummy_address(), onchain_amount)]
        coins = self.window.get_coins()
        try:
            self.tx = self.window.wallet.make_unsigned_transaction(
                coins=coins,
                outputs=outputs)
        except (NotEnoughFunds, NoDynamicFeeEstimates) as e:
            self.tx = None

    def update_ok_button(self):
        """Updates self.ok_button. No other side-effects."""
        send_amount = self.send_amount_e.get_amount()
        recv_amount = self.recv_amount_e.get_amount()
        self.ok_button.setEnabled(
            (send_amount is not None)
            and (recv_amount is not None)
            and (self.tx is not None or self.is_reverse)
        )

    def do_normal_swap(self, lightning_amount, onchain_amount, password):
        tx = self.tx
        assert tx
        coro = self.swap_manager.normal_swap(
            lightning_amount_sat=lightning_amount,
            expected_onchain_amount_sat=onchain_amount,
            password=password,
            tx=tx,
        )
        self.window.run_coroutine_from_thread(coro)

    def get_description(self):
        onchain_funds = "onchain funds"
        lightning_funds = "lightning funds"

        return "Swap {fromType} for {toType}. This will increase your {capacityType} capacity. This service is powered by the Boltz backend.".format(
            fromType=lightning_funds if self.is_reverse else onchain_funds,
            toType=onchain_funds if self.is_reverse else lightning_funds,
            capacityType="receiving" if self.is_reverse else "sending",
        )
