# Copyright (C) 2024–present  Loren Eteval & contributors <loren.eteval@proton.me>
#
# This file is part of Furious.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

"""Present subscription definitions and synchronization as a dedicated page."""

from __future__ import annotations

from Furious.Frozenlib import APP, Mixins, PySide6Legacy
from Furious.Qt import (
    AppQComboBox,
    AppQDialog,
    AppQDialogButtonBox,
    AppQLabel,
    AppQLineEdit,
    AppQMessageBox,
    AppQPushButton,
    AppQSwitch,
    AppQTransientDialog,
    AppStyleSheet,
    bootstrapIcon,
    bootstrapIconWhite,
)
from Furious.Qt import gettext as _
from Furious.Qt.Signals import connectWeakly
from Furious.Repository import Storage
from Furious.Widget.SubscriptionTableView import SubscriptionTableView

from PySide6 import QtCore
from PySide6.QtWidgets import (
    QApplication,
    QFrame,
    QGridLayout,
    QHBoxLayout,
    QMainWindow,
    QVBoxLayout,
    QWidget,
)

from urllib.parse import urlsplit

import uuid

__all__ = ['SubscriptionPage']


def _validSubscriptionURL(value) -> str:
    """Return a normalized HTTP(S) subscription URL or an empty string."""
    url = str(value or '').strip()

    if not url or any(character.isspace() for character in url):
        return ''

    try:
        parsed = urlsplit(url)
        hostname = parsed.hostname
    except ValueError:
        return ''

    if parsed.scheme.casefold() not in ('http', 'https') or not hostname:
        return ''

    return url


class _SubscriptionEditorDialog(AppQTransientDialog):
    """Edit one complete subscription definition with validation."""

    def __init__(self, subscription=None, parent=None):
        """Initialize fields from an existing definition or defaults."""
        super().__init__(parent)

        subscription = dict(subscription or {})

        (
            self.remarkEdit,
            self.urlEdit,
            self.enabledSwitch,
            self.autoUpdateComboBox,
            self.proxyComboBox,
            self.userAgentEdit,
            self.filterEdit,
        ) = (
            AppQLineEdit(subscription.get('remark', '')),
            AppQLineEdit(subscription.get('webURL', '')),
            AppQSwitch(),
            AppQComboBox(),
            AppQComboBox(),
            AppQLineEdit(subscription.get('userAgent', '')),
            AppQLineEdit(subscription.get('filter', '')),
        )

        self.remarkEdit.setMinimumWidth(240)
        self.remarkEdit.setMaximumWidth(360)
        self.urlEdit.setMinimumWidth(420)
        self.enabledSwitch.syncChecked(subscription.get('enabled', True))
        self.autoUpdateComboBox.setMinimumWidth(220)
        self.autoUpdateComboBox.setContentWidthAdjustable()
        self.proxyComboBox.setMinimumWidth(220)
        self.proxyComboBox.setContentWidthAdjustable()
        self.userAgentEdit.setMinimumWidth(260)
        self.filterEdit.setMinimumWidth(260)

        for value in SubscriptionTableView.AutoUpdateOptions:
            self.autoUpdateComboBox.addItem(_(value), value)

        for value in SubscriptionTableView.ProxyOptions:
            self.proxyComboBox.addItem(_(value), value)

        autoIndex, proxyIndex = (
            self.autoUpdateComboBox.findData(subscription.get('autoupdate', '')),
            self.proxyComboBox.findData(subscription.get('proxy', '')),
        )

        self.autoUpdateComboBox.setCurrentIndex(max(autoIndex, 0))
        self.proxyComboBox.setCurrentIndex(max(proxyIndex, 0))

        self.buttons = AppQDialogButtonBox(QtCore.Qt.Orientation.Horizontal)
        self.buttons.addButton(_('OK'), AppQDialogButtonBox.ButtonRole.AcceptRole)
        self.buttons.addButton(
            _('Cancel'),
            AppQDialogButtonBox.ButtonRole.RejectRole,
        )

        connectWeakly(self.buttons.accepted, self, 'accept')
        connectWeakly(self.buttons.rejected, self, 'reject')

        formWidget = QFrame()
        formWidget.setObjectName('SubscriptionEditorForm')

        form = QGridLayout(formWidget)
        form.setContentsMargins(20, 18, 20, 18)
        form.setHorizontalSpacing(16)
        form.setVerticalSpacing(14)
        form.setColumnStretch(1, 1)
        form.setColumnStretch(3, 1)

        (
            self.remarkLabel,
            self.urlLabel,
            self.enabledLabel,
            self.autoUpdateLabel,
            self.proxyLabel,
            self.userAgentLabel,
            self.filterLabel,
        ) = (
            AppQLabel(_('Remark')),
            AppQLabel(_('URL')),
            AppQLabel(_('Enabled')),
            AppQLabel(_('Auto Update')),
            AppQLabel(_('Auto Update Use Proxy')),
            AppQLabel(_('User Agent')),
            AppQLabel(_('Profile Filter (Regex)')),
        )

        enabledLayout = QHBoxLayout()
        enabledLayout.setContentsMargins(0, 0, 0, 0)
        enabledLayout.setSpacing(10)
        enabledLayout.addWidget(self.enabledLabel)
        enabledLayout.addWidget(self.enabledSwitch)
        enabledLayout.addStretch(1)

        form.addWidget(self.remarkLabel, 0, 0)
        form.addWidget(self.remarkEdit, 0, 1)
        form.addLayout(enabledLayout, 0, 2, 1, 2)
        form.addWidget(self.urlLabel, 1, 0)
        form.addWidget(self.urlEdit, 1, 1, 1, 3)
        form.addWidget(self.autoUpdateLabel, 2, 0)
        form.addWidget(self.autoUpdateComboBox, 2, 1)
        form.addWidget(self.proxyLabel, 2, 2)
        form.addWidget(self.proxyComboBox, 2, 3)
        form.addWidget(self.userAgentLabel, 3, 0)
        form.addWidget(self.userAgentEdit, 3, 1)
        form.addWidget(self.filterLabel, 3, 2)
        form.addWidget(self.filterEdit, 3, 3)

        buttonsLayout = QHBoxLayout()
        buttonsLayout.setContentsMargins(0, 0, 0, 0)
        buttonsLayout.addStretch(1)
        buttonsLayout.addWidget(self.buttons)

        layout = QVBoxLayout(self)
        layout.setContentsMargins(20, 20, 20, 18)
        layout.setSpacing(16)
        layout.addWidget(formWidget)
        layout.addLayout(buttonsLayout)

        self.setWindowTitle(
            _('Edit Subscription') if subscription else _('Add Subscription')
        )
        self.resize(900, 330)

    def _showValidationError(self, message: str):
        """Show one non-blocking validation message owned by this dialog."""
        mbox = AppQMessageBox(icon=AppQMessageBox.Icon.Warning, parent=self)
        mbox.setHeading(_('Invalid data'))
        mbox.setText(message)
        mbox.open()

    def accept(self):
        """Validate required fields before accepting the definition."""
        remark, url = (
            self.remarkEdit.text().strip(),
            _validSubscriptionURL(self.urlEdit.text()),
        )

        if not remark:
            self._showValidationError(_('Please enter a subscription remark.'))

            return

        if not url:
            self._showValidationError(_('Please enter a valid subscription URL.'))

            return

        super().accept()

    def subscription(self):
        """Return the normalized values entered by the user."""
        return {
            'remark': self.remarkEdit.text().strip(),
            'webURL': self.urlEdit.text().strip(),
            'enabled': self.enabledSwitch.isChecked(),
            'autoupdate': self.autoUpdateComboBox.currentData() or '',
            'proxy': self.proxyComboBox.currentData() or '',
            'userAgent': self.userAgentEdit.text().strip(),
            'filter': self.filterEdit.text().strip(),
        }


class SubscriptionPage(Mixins.QTranslatable, Mixins.ThemeAware, QMainWindow):
    """Own subscription editing, grouping, and synchronization workflows."""

    def __init__(self, serverTable, parent=None):
        """Initialize around the existing profile synchronization backend."""
        super().__init__(parent)

        self.setObjectName('SubscriptionPage')

        self.serverTable = serverTable

        self.pageTitleLabel = AppQLabel(_('Subscriptions'))
        self.pageTitleLabel.setObjectName('SubscriptionPageTitle')

        self.proxyLabel = AppQLabel(_('Update Using'))

        self.proxyComboBox = AppQComboBox()
        self.proxyComboBox.setContentWidthAdjustable()
        self.proxyComboBox.setMinimumWidth(160)

        (
            self.addButton,
            self.editButton,
            self.deleteButton,
            self.copyURLButton,
            self.viewProfilesButton,
            self.updateSelectedButton,
            self.updateAllButton,
        ) = (
            AppQPushButton(_('Add')),
            AppQPushButton(_('Edit')),
            AppQPushButton(_('Delete')),
            AppQPushButton(_('Copy URL')),
            AppQPushButton(_('View Profiles')),
            AppQPushButton(_('Update Selected')),
            AppQPushButton(_('Update All')),
        )

        self.table = SubscriptionTableView(
            deleteUniqueCallback=self._deleteProfilesForSubscription,
            subscriptionManager=self.serverTable.subsManager,
            parent=self,
        )
        self.table.doubleClicked.connect(self._editDoubleClicked)
        self.table.groupsChanged.connect(
            self.serverTable.subsManager.subscriptionsChanged.emit
        )

        # The manager and table are persistent main-window children. This direct
        # connection intentionally shares their process-lifetime ownership.
        self.serverTable.subsManager.subscriptionStateChanged.connect(
            self.table.refreshSubscriptionState
        )

        self.addButton.clicked.connect(self.addSubscription)
        self.editButton.clicked.connect(self.editSelected)
        self.deleteButton.clicked.connect(self.table.deleteSelectedItem)
        self.copyURLButton.clicked.connect(self.copySelectedURL)
        self.viewProfilesButton.clicked.connect(self.viewSelectedProfiles)
        self.updateSelectedButton.clicked.connect(self.updateSelected)
        self.updateAllButton.clicked.connect(self.updateAll)

        for key in SubscriptionTableView.ProxyOptions:
            self.proxyComboBox.addItem(_(key), key)

        controls = QHBoxLayout()
        controls.setContentsMargins(0, 0, 0, 0)
        controls.setSpacing(8)
        controls.addWidget(self.pageTitleLabel)
        controls.addStretch(1)
        controls.addWidget(self.proxyLabel)
        controls.addWidget(self.proxyComboBox)
        controls.addWidget(self.updateSelectedButton)
        controls.addWidget(self.updateAllButton)

        actions = QHBoxLayout()
        actions.setContentsMargins(0, 0, 0, 0)
        actions.setSpacing(8)
        actions.addWidget(self.addButton)
        actions.addWidget(self.editButton)
        actions.addWidget(self.deleteButton)
        actions.addWidget(self.copyURLButton)
        actions.addWidget(self.viewProfilesButton)
        actions.addStretch(1)

        content = QWidget()
        content.setObjectName('SubscriptionPageContent')

        layout = QVBoxLayout(content)
        layout.setContentsMargins(20, 18, 20, 20)
        layout.setSpacing(12)
        layout.addLayout(controls)
        layout.addLayout(actions)
        layout.addWidget(self.table, 1)

        self.setCentralWidget(content)

        self.setIconsByTheme(APP().theme())
        self.retranslate()

    @QtCore.Slot(QtCore.QModelIndex)
    def _editDoubleClicked(self, _index):
        """Edit the selected subscription after a table double-click."""
        self.editSelected()

    def _deleteProfilesForSubscription(self, unique: str):
        """Remove profiles belonging to a deleted subscription group."""
        indexes = [
            index
            for index, server in enumerate(Storage.UserServers())
            if server.itemSubscription == unique and server.itemSubscriptionManaged
        ]

        self.serverTable.deleteItemByIndex(indexes, showProgress=False)

        for server in Storage.UserServers():
            if server.itemSubscription == unique:
                server.metadata.subscriptionSource = ''
                server.metadata.subscriptionManaged = False
                server.metadata.subscriptionProfileKey = ''

        self.serverTable.flushAll()

    def _selectedUnique(self):
        """Return the first selected subscription ID, if any."""
        selected = self.table.selectedUniques

        return selected[0] if selected else None

    def _openEditor(self, unique=None, initial=None):
        """Open and retain an asynchronous add/edit dialog."""
        source = Storage.UserSubs().get(unique, initial or {})

        dialog = _SubscriptionEditorDialog(source, parent=self)
        dialog.setWindowTitle(
            _('Edit Subscription') if unique else _('Add Subscription')
        )
        dialog.setWindowModality(QtCore.Qt.WindowModality.WindowModal)

        def finished(code):
            """Persist accepted values through the existing table model."""
            if code != PySide6Legacy.enumValueWrapper(AppQDialog.DialogCode.Accepted):
                return

            subscriptionUnique = unique or str(uuid.uuid4())
            existing = Storage.UserSubs().get(subscriptionUnique, {})

            self.table.appendNewItem(
                unique=subscriptionUnique,
                lastUpdated=existing.get('lastUpdated', ''),
                **dialog.subscription(),
            )
            self.table.selectRow(list(Storage.UserSubs()).index(subscriptionUnique))

        dialog.finished.connect(finished)
        dialog.open()

        return dialog

    @QtCore.Slot()
    def addSubscription(self):
        """Offer a valid clipboard URL before opening the normal editor."""
        url = _validSubscriptionURL(QApplication.clipboard().text())

        if not url:
            self._openEditor()

            return

        mbox = AppQMessageBox(icon=AppQMessageBox.Icon.Question, parent=self)
        mbox.setText(_('Use the subscription URL from the clipboard?'))
        mbox.setInformativeText(url)
        mbox.setStandardButtons(
            AppQMessageBox.StandardButton.Yes | AppQMessageBox.StandardButton.No
        )
        mbox.setDefaultButton(AppQMessageBox.StandardButton.Yes)
        mbox.setWindowModality(QtCore.Qt.WindowModality.WindowModal)

        def finished(code):
            """Continue with clipboard assistance or the regular workflow."""
            if code == PySide6Legacy.enumValueWrapper(
                AppQMessageBox.StandardButton.Yes
            ):
                self.addFromClipboard(url)
            else:
                self._openEditor()

        mbox.finished.connect(finished)
        mbox.open()

    def addFromClipboard(self, clipboardURL=None):
        """Seed a subscription from an HTTP(S) URL on the clipboard."""
        if clipboardURL is None:
            clipboardURL = QApplication.clipboard().text()

        url = _validSubscriptionURL(clipboardURL)

        if not url:
            self._openEditor()

            return

        parsed = urlsplit(url)

        self._openEditor(
            initial={
                'remark': parsed.hostname or _('Subscription'),
                'webURL': url,
                'enabled': True,
            }
        )

    @QtCore.Slot()
    def editSelected(self):
        """Edit the selected subscription without relying on inline cells."""
        unique = self._selectedUnique()

        if unique is not None:
            self._openEditor(unique)

    @QtCore.Slot()
    def copySelectedURL(self):
        """Copy the selected subscription URL for sharing/export."""
        unique = self._selectedUnique()

        if unique is not None:
            QApplication.clipboard().setText(
                str(Storage.UserSubs()[unique].get('webURL', ''))
            )

    @QtCore.Slot()
    def viewSelectedProfiles(self):
        """Open Home filtered to the selected subscription group."""
        unique = self._selectedUnique()

        if unique is None:
            return

        mainWindow = self.window()

        homePage = getattr(mainWindow, 'homePage', None)

        if homePage is not None:
            homePage.showSubscriptionGroup(unique)

        showPage = getattr(mainWindow, 'showPage', None)

        if callable(showPage):
            showPage('home')

    def _selectedProxy(self):
        """Resolve the proxy policy selected for manual synchronization."""
        key = self.proxyComboBox.currentData() or ''
        resolver = SubscriptionTableView.ProxyOptions.get(key)

        return resolver() if callable(resolver) else None

    @QtCore.Slot()
    def updateSelected(self):
        """Synchronize selected enabled subscription groups together."""
        keys = tuple(
            key
            for key in self.table.selectedUniques
            if Storage.UserSubs().get(key, {}).get('enabled', True)
            and Storage.UserSubs().get(key, {}).get('webURL')
        )

        if not keys:
            return

        self.serverTable.updateSubscriptions(
            keys,
            self._selectedProxy(),
            showMessageBox=True,
            parent=self,
        )

    @QtCore.Slot()
    def updateAll(self):
        """Synchronize every enabled subscription with one proxy policy."""
        self.serverTable.updateSubs(self._selectedProxy(), parent=self)

    def updateSubsByUnique(self, unique: str, httpProxy, **kwargs):
        """Preserve the established application subscription-update API."""
        self.serverTable.updateSubsByUnique(unique, httpProxy, **kwargs)

    def setIconsByTheme(self, theme: str):
        """Apply theme-aware Fluent icons to subscription commands."""
        iconFactory = (
            bootstrapIconWhite if theme == AppStyleSheet.Dark else bootstrapIcon
        )

        for button, iconName in (
            (self.addButton, 'plus-lg.svg'),
            (self.editButton, 'pencil-square.svg'),
            (self.deleteButton, 'trash.svg'),
            (self.copyURLButton, 'link-45deg.svg'),
            (self.viewProfilesButton, 'funnel.svg'),
            (self.updateSelectedButton, 'arrow-repeat.svg'),
            (self.updateAllButton, 'cloud-arrow-down.svg'),
        ):
            button.setIcon(iconFactory(iconName))

    def themeChangedCallback(self, theme: str):
        """Refresh command icons after a theme change."""
        self.setIconsByTheme(theme)

    def showEvent(self, event):
        """Refresh persisted subscription data whenever the page is shown."""
        super().showEvent(event)

        self.table.flushAll()

    def retranslate(self):
        """Handle page-level dynamic translation state."""
        pass