#!/usr/bin/env python3

#******************************************************************************
# conditional.py, provides a class to store field comparison functions
#
# TreeLine, an information storage program
# Copyright (C) 2017, Douglas W. Bell
#
# This is free software; you can redistribute it and/or modify it under the
# terms of the GNU General Public License, either Version 2 or any later
# version.  This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY.  See the included LICENSE file for details.
#******************************************************************************

import re
import enum
from PyQt5.QtCore import QSize, Qt, pyqtSignal
from PyQt5.QtWidgets import (QComboBox, QDialog, QGroupBox, QHBoxLayout,
                             QLabel, QLineEdit, QListWidget, QPushButton,
                             QSizePolicy, QVBoxLayout)
import treeformats
import configdialog
import undo
import globalref

_operators = ['==', '<', '<=', '>', '>=', '!=', N_('starts with'),
              N_('ends with'), N_('contains'), N_('True'), N_('False')]
_functions = {'==': '__eq__', '<': '__lt__', '<=': '__le__',
              '>': '__gt__', '>=': '__ge__', '!=': '__ne__',
              'starts with': 'startswith', 'ends with': 'endswith',
              'contains': 'contains', 'True': 'true', 'False': 'false'}
_boolOper = [N_('and'), N_('or')]
_allTypeEntry = _('[All Types]')
_parseRe = re.compile(r'((?:and)|(?:or)) (\S+) (.+?) '
                      r'(?:(?<!\\)"|(?<=\\\\)")(.*?)(?:(?<!\\)"|(?<=\\\\)")')


class Conditional:
    """Stores and evaluates a conditional comparison for field data.
    """
    def __init__(self, conditionStr='', nodeFormatName=''):
        """Initialize the condition object.

        Accepts a string in the following format:
        'fieldname == "value" and otherFieldName > "othervalue"'
        Arguments:
            conditionStr -- the condition string to set
            nodeFormatName -- if name is set, restricts matches to type family
        """
        self.conditionLines = []
        conditionStr = 'and ' + conditionStr
        for boolOper, fieldName, oper, value in _parseRe.findall(conditionStr):
            value = value.replace('\\"', '"').replace('\\\\', '\\')
            self.conditionLines.append(ConditionLine(boolOper, fieldName,
                                                     oper, value))
        self.origNodeFormatName = nodeFormatName
        self.nodeFormatNames = set()
        if nodeFormatName:
            self.nodeFormatNames.add(nodeFormatName)
            nodeFormats = (globalref.mainControl.activeControl.structure.
                           treeFormats)
            for nodeType in nodeFormats[nodeFormatName].derivedTypes:
                self.nodeFormatNames.add(nodeType.name)

    def evaluate(self, node):
        """Evaluate this condition and return True or False.

        Arguments:
            node -- the node to check for a field match
        """
        if (self.nodeFormatNames and
            node.formatRef.name not in self.nodeFormatNames):
            return False
        result = True
        for conditon in self.conditionLines:
            result = conditon.evaluate(node, result)
        return result

    def conditionStr(self):
        """Return the condition string for this condition set.
        """
        return ' '.join([cond.conditionStr() for cond in
                         self.conditionLines])[4:]

    def renameFields(self, oldName, newName):
        """Rename the any fields found in condition lines.

        Arguments:
            oldName -- the previous field name
            newName -- the updated field name
        """
        for condition in self.conditionLines:
            if condition.fieldName == oldName:
                condition.fieldName = newName

    def removeField(self, fieldname):
        """Remove conditional lines referencing the given field.

        Arguments:
            fieldname -- the field name to be removed
        """
        for condition in self.conditionLines[:]:
            if condition.fieldName == fieldname:
                self.conditionLines.remove(condition)

    def __len__(self):
        """Return the number of conditions for truth testing.
        """
        return len(self.conditionLines)


class ConditionLine:
    """Stores & evaluates a portion of a conditional comparison.
    """
    def __init__(self, boolOper, fieldName, oper, value):
        """Initialize the condition line.

        Arguments:
            boolOper -- a string for combining previous lines ('and' or 'or')
            fieldName -- the field name to evaluate
            oper -- the operator string
            value -- the string for comparison
        """
        self.boolOper = boolOper
        self.fieldName = fieldName
        self.oper = oper
        self.value = value

    def evaluate(self, node, prevResult=True):
        """Evaluate this line and return True or False.

        Arguments:
            node -- the node to check for a field match
            prevResult -- the result to combine with the boolOper
        """
        try:
            field = node.formatRef.fieldDict[self.fieldName]
        except KeyError:
            if self.boolOper == 'and':
                return False
            return prevResult
        dataStr = field.compareValue(node)
        value = field.adjustedCompareValue(self.value)
        try:
            func = getattr(dataStr, _functions[self.oper])
        except AttributeError:
            dataStr = StringOps(dataStr)
            func = getattr(dataStr, _functions[self.oper])
            value = str(value)
        if self.boolOper == 'and':
            return prevResult and func(value)
        else:
            return prevResult or func(value)

    def conditionStr(self):
        """Return the text line for this condition.
        """
        value = self.value.replace('\\', '\\\\').replace('"', '\\"')
        return '{0} {1} {2} "{3}"'.format(self.boolOper, self.fieldName,
                                          self.oper, value)


class StringOps(str):
    """A string class with extra comparison functions.
    """
    def __new__(cls, initStr=''):
        """Return the str object.

        Arguments:
            initStr -- the initial string value
        """
        return str.__new__(cls, initStr)

    def contains(self, substr):
        """Return True if self contains substr.

        Arguments:
            substr -- the substring to check
        """
        return self.find(substr) != -1

    def true(self, other=''):
        """Always return True.

        Arguments:
            other -- unused placeholder
        """
        return True

    def false(self, other=''):
        """Always return False.

        Arguments:
            other -- unused placeholder
        """
        return False


FindDialogType = enum.Enum('FindDialogType',
                           'typeDialog findDialog filterDialog')

class ConditionDialog(QDialog):
    """Dialog for defining field condition tests.

    Used for defining conditional types (modal), for finding by condition
    (nonmodal) and for filtering by condition (nonmodal).
    """
    dialogShown = pyqtSignal(bool)
    def __init__(self, dialogType, caption, nodeFormat=None, parent=None):
        """Create the conditional dialog.

        Arguments:
            dialogType -- either typeDialog, findDialog or filterDialog
            caption -- the window title for this dialog
            nodeFormat -- the current node format for the typeDialog
            parent -- the parent overall dialog
        """
        super().__init__(parent)
        self.setWindowTitle(caption)
        self.dialogType = dialogType
        self.ruleList = []
        self.combiningBoxes = []
        self.typeCombo = None
        self.resultLabel = None
        self.endFilterButton = None
        self.fieldNames = []
        if nodeFormat:
            self.fieldNames = nodeFormat.fieldNames()
        topLayout = QVBoxLayout(self)

        if dialogType == FindDialogType.typeDialog:
            self.setWindowFlags(Qt.Dialog | Qt.WindowTitleHint |
                                Qt.WindowCloseButtonHint)
        else:
            self.setAttribute(Qt.WA_QuitOnClose, False)
            self.setWindowFlags(Qt.Window |
                                Qt.WindowStaysOnTopHint)
            typeBox = QGroupBox(_('Node Type'))
            topLayout.addWidget(typeBox)
            typeLayout = QVBoxLayout(typeBox)
            self.typeCombo = QComboBox()
            typeLayout.addWidget(self.typeCombo)
            self.typeCombo.currentIndexChanged.connect(self.updateDataType)

        self.mainLayout = QVBoxLayout()
        topLayout.addLayout(self.mainLayout)

        upCtrlLayout = QHBoxLayout()
        topLayout.addLayout(upCtrlLayout)
        addButton = QPushButton(_('&Add New Rule'))
        upCtrlLayout.addWidget(addButton)
        addButton.clicked.connect(self.addNewRule)
        self.removeButton = QPushButton(_('&Remove Rule'))
        upCtrlLayout.addWidget(self.removeButton)
        self.removeButton.clicked.connect(self.removeRule)
        upCtrlLayout.addStretch()

        if dialogType == FindDialogType.typeDialog:
            okButton = QPushButton(_('&OK'))
            upCtrlLayout.addWidget(okButton)
            okButton.clicked.connect(self.accept)
            cancelButton = QPushButton(_('&Cancel'))
            upCtrlLayout.addWidget(cancelButton)
            cancelButton.clicked.connect(self.reject)
        else:
            self.removeButton.setEnabled(False)
            saveBox = QGroupBox(_('Saved Rules'))
            topLayout.addWidget(saveBox)
            saveLayout = QVBoxLayout(saveBox)
            self.saveListBox = SmallListWidget()
            saveLayout.addWidget(self.saveListBox)
            self.saveListBox.itemDoubleClicked.connect(self.loadSavedRule)
            nameLayout = QHBoxLayout()
            saveLayout.addLayout(nameLayout)
            label = QLabel(_('Name:'))
            nameLayout.addWidget(label)
            self.saveNameEdit = QLineEdit()
            nameLayout.addWidget(self.saveNameEdit)
            self.saveNameEdit.textChanged.connect(self.updateSaveEnable)
            saveButtonLayout = QHBoxLayout()
            saveLayout.addLayout(saveButtonLayout)
            self.loadSavedButton = QPushButton(_('&Load'))
            saveButtonLayout.addWidget(self.loadSavedButton)
            self.loadSavedButton.clicked.connect(self.loadSavedRule)
            self.saveButton = QPushButton(_('&Save'))
            saveButtonLayout.addWidget(self.saveButton)
            self.saveButton.clicked.connect(self.saveRule)
            self.saveButton.setEnabled(False)
            self.delSavedButton = QPushButton(_('&Delete'))
            saveButtonLayout.addWidget(self.delSavedButton)
            self.delSavedButton.clicked.connect(self.deleteRule)
            saveButtonLayout.addStretch()

            if dialogType == FindDialogType.findDialog:
                self.resultLabel = QLabel()
                topLayout.addWidget(self.resultLabel)
            lowCtrlLayout = QHBoxLayout()
            topLayout.addLayout(lowCtrlLayout)
            if dialogType == FindDialogType.findDialog:
                previousButton = QPushButton(_('Find &Previous'))
                lowCtrlLayout.addWidget(previousButton)
                previousButton.clicked.connect(self.findPrevious)
                nextButton = QPushButton(_('Find &Next'))
                nextButton.setDefault(True)
                lowCtrlLayout.addWidget(nextButton)
                nextButton.clicked.connect(self.findNext)
            else:
                filterButton = QPushButton(_('&Filter'))
                lowCtrlLayout.addWidget(filterButton)
                filterButton.clicked.connect(self.startFilter)
                self.endFilterButton = QPushButton(_('&End Filter'))
                lowCtrlLayout.addWidget(self.endFilterButton)
                self.endFilterButton.setEnabled(False)
                self.endFilterButton.clicked.connect(self.endFilter)
            lowCtrlLayout.addStretch()
            closeButton = QPushButton(_('&Close'))
            lowCtrlLayout.addWidget(closeButton)
            closeButton.clicked.connect(self.close)
            origTypeName = nodeFormat.name if nodeFormat else ''
            self.loadTypeNames(origTypeName)
            self.loadSavedNames()
        self.ruleList.append(ConditionRule(1, self.fieldNames))
        self.mainLayout.addWidget(self.ruleList[0])

    def addNewRule(self, checked=False, combineBool='and'):
        """Add a new empty rule to the dialog.

        Arguments:
            checked -- unused placekeeper variable for signal
            combineBool -- the boolean op for combining with the previous rule
        """
        if self.ruleList:
            boolBox = QComboBox()
            boolBox.setEditable(False)
            self.combiningBoxes.append(boolBox)
            boolBox.addItems([_(op) for op in _boolOper])
            if combineBool != 'and':
                boolBox.setCurrentIndex(1)
            self.mainLayout.insertWidget(len(self.ruleList) * 2 - 1, boolBox,
                                        0, Qt.AlignHCenter)
        rule = ConditionRule(len(self.ruleList) + 1, self.fieldNames)
        self.ruleList.append(rule)
        self.mainLayout.insertWidget(len(self.ruleList) * 2 - 2, rule)
        self.removeButton.setEnabled(True)

    def removeRule(self):
        """Remove the last rule from the dialog.
        """
        if self.ruleList:
            if self.combiningBoxes:
                self.combiningBoxes[-1].hide()
                del self.combiningBoxes[-1]
            self.ruleList[-1].hide()
            del self.ruleList[-1]
            if self.dialogType == FindDialogType.typeDialog:
                self.removeButton.setEnabled(len(self.ruleList) > 0)
            else:
                self.removeButton.setEnabled(len(self.ruleList) > 1)

    def clearRules(self):
        """Remove all rules from the dialog and add default rule.
        """
        for box in self.combiningBoxes:
            box.hide()
        for rule in self.ruleList:
            rule.hide()
        self.combiningBoxes = []
        self.ruleList = [ConditionRule(1, self.fieldNames)]
        self.mainLayout.insertWidget(0, self.ruleList[0])
        self.removeButton.setEnabled(True)

    def setCondition(self, conditional, typeName=''):
        """Set rule values to match the given conditional.

        Arguments:
            conditional -- the Conditional class to match
            typeName -- an optional type name used with some dialog types
        """
        if self.typeCombo:
            if typeName:
                self.typeCombo.setCurrentIndex(self.typeCombo.
                                               findText(typeName))
            else:
                self.typeCombo.setCurrentIndex(0)
        while len(self.ruleList) > 1:
            self.removeRule()
        if conditional:
            self.ruleList[0].setCondition(conditional.conditionLines[0])
        for conditionLine in conditional.conditionLines[1:]:
            self.addNewRule(combineBool=conditionLine.boolOper)
            self.ruleList[-1].setCondition(conditionLine)

    def conditional(self):
        """Return a Conditional instance for the current settings.
        """
        combineBools = [0] + [boolBox.currentIndex() for boolBox in
                              self.combiningBoxes]
        typeName = self.typeCombo.currentText() if self.typeCombo else ''
        if typeName == _allTypeEntry:
            typeName = ''
        conditional = Conditional('', typeName)
        for boolIndex, rule in zip(combineBools, self.ruleList):
            condition = rule.conditionLine()
            if boolIndex != 0:
                condition.boolOper = 'or'
            conditional.conditionLines.append(condition)
        return conditional

    def loadTypeNames(self, origTypeName=''):
        """Load format type names into combo box.

        Arguments:
            origTypeName -- a starting type name if given
        """
        if not origTypeName:
            origTypeName = self.typeCombo.currentText()
        nodeFormats = globalref.mainControl.activeControl.structure.treeFormats
        self.typeCombo.blockSignals(True)
        self.typeCombo.clear()
        self.typeCombo.addItem(_allTypeEntry)
        typeNames = nodeFormats.typeNames()
        self.typeCombo.addItems(typeNames)
        if origTypeName and origTypeName != _allTypeEntry:
            try:
                self.typeCombo.setCurrentIndex(typeNames.index(origTypeName)
                                               + 1)
            except ValueError:
                if self.endFilterButton and self.endFilterButton.isEnabled():
                    self.endFilter()
                self.clearRules()
        self.typeCombo.blockSignals(False)
        self.updateDataType()

    def updateDataType(self):
        """Update the node format based on a data type change.
        """
        typeName = self.typeCombo.currentText()
        if not typeName:
            return
        nodeFormats = globalref.mainControl.activeControl.structure.treeFormats
        if typeName == _allTypeEntry:
            fieldNameSet = set()
            for typeFormat in nodeFormats.values():
                fieldNameSet.update(typeFormat.fieldNames())
            self.fieldNames = sorted(list(fieldNameSet))
        else:
            self.fieldNames = nodeFormats[typeName].fieldNames()
        for rule in self.ruleList:
            currentField = rule.conditionLine().fieldName
            if currentField not in self.fieldNames:
                if self.endFilterButton and self.endFilterButton.isEnabled():
                    self.endFilter()
                self.clearRules()
                break
            rule.reloadFieldBox(self.fieldNames, currentField)

    def loadSavedNames(self, updateOtherDialog=False):
        """Refresh the list of saved rule names.
        """
        selNum = 0
        if self.saveListBox.count():
            selNum = self.saveListBox.currentRow()
        self.saveListBox.clear()
        nodeFormats = globalref.mainControl.activeControl.structure.treeFormats
        savedRules = nodeFormats.savedConditions()
        ruleNames = sorted(list(savedRules.keys()))
        if ruleNames:
            self.saveListBox.addItems(ruleNames)
            if selNum >= len(ruleNames):
                selNum = len(ruleNames) - 1
            self.saveListBox.setCurrentRow(selNum)
        self.loadSavedButton.setEnabled(len(ruleNames) > 0)
        self.delSavedButton.setEnabled(len(ruleNames) > 0)
        if updateOtherDialog:
            if (self != globalref.mainControl.findConditionDialog and
                globalref.mainControl.findConditionDialog and
                globalref.mainControl.findConditionDialog.isVisible()):
                globalref.mainControl.findConditionDialog.loadSavedNames()
            elif (self != globalref.mainControl.filterConditionDialog and
                  globalref.mainControl.filterConditionDialog and
                  globalref.mainControl.filterConditionDialog .isVisible()):
                globalref.mainControl.filterConditionDialog.loadSavedNames()

    def updateSaveEnable(self):
        """Set the save rule button enabled based on save name entry.
        """
        self.saveButton.setEnabled(len(self.saveNameEdit.text()))

    def updateFilterControls(self):
        """Set filter button status based on active window changes.
        """
        window = globalref.mainControl.activeControl.activeWindow
        if window.treeFilterView:
            filterView = window.treeFilterView
            conditional = filterView.conditionalFilter
            self.setCondition(conditional, conditional.origNodeFormatName)
            self.endFilterButton.setEnabled(True)
        else:
            self.endFilterButton.setEnabled(False)

    def loadSavedRule(self):
        """Load the current saved rule into the dialog.
        """
        nodeFormats = globalref.mainControl.activeControl.structure.treeFormats
        savedRules = nodeFormats.savedConditions()
        ruleName = self.saveListBox.currentItem().text()
        conditional = savedRules[ruleName]
        self.setCondition(conditional, conditional.origNodeFormatName)

    def saveRule(self):
        """Save the current rule settings.
        """
        name = self.saveNameEdit.text()
        self.saveNameEdit.setText('')
        treeStructure = globalref.mainControl.activeControl.structure
        undo.FormatUndo(treeStructure.undoList, treeStructure.treeFormats,
                        treeformats.TreeFormats())
        typeName = self.typeCombo.currentText()
        if typeName == _allTypeEntry:
            nodeFormat = treeStructure.treeFormats
        else:
            nodeFormat = treeStructure.treeFormats[typeName]
        nodeFormat.savedConditionText[name] = (self.conditional().
                                               conditionStr())
        self.loadSavedNames(True)
        self.saveListBox.setCurrentItem(self.saveListBox.
                                        findItems(name, Qt.MatchExactly)[0])
        globalref.mainControl.activeControl.setModified()

    def deleteRule(self):
        """Remove the current saved rule.
        """
        treeStructure = globalref.mainControl.activeControl.structure
        nodeFormats = treeStructure.treeFormats
        undo.FormatUndo(treeStructure.undoList, nodeFormats,
                        treeformats.TreeFormats())
        savedRules = nodeFormats.savedConditions()
        ruleName = self.saveListBox.currentItem().text()
        conditional = savedRules[ruleName]
        if conditional.origNodeFormatName:
            typeFormat = nodeFormats[conditional.
                                     origNodeFormatName]
            del typeFormat.savedConditionText[ruleName]
        else:
            del nodeFormats.savedConditionText[ruleName]
        self.loadSavedNames(True)
        globalref.mainControl.activeControl.setModified()

    def find(self, forward=True):
        """Find another match in the indicated direction.

        Arguments:
            forward -- next if True, previous if False
        """
        self.resultLabel.setText('')
        conditional = self.conditional()
        control = globalref.mainControl.activeControl
        if not control.findNodesByCondition(conditional, forward):
            self.resultLabel.setText(_('No conditional matches were found'))

    def findPrevious(self):
        """Find the previous match.
        """
        self.find(False)

    def  findNext(self):
        """Find the next match.
        """
        self.find(True)

    def startFilter(self):
        """Start filtering nodes.
        """
        window = globalref.mainControl.activeControl.activeWindow
        filterView = window.filterView()
        filterView.conditionalFilter = self.conditional()
        filterView.updateContents()
        self.endFilterButton.setEnabled(True)

    def endFilter(self):
        """Stop filtering nodes.
        """
        window = globalref.mainControl.activeControl.activeWindow
        window.removeFilterView()
        self.endFilterButton.setEnabled(False)

    def closeEvent(self, event):
        """Signal that the dialog is closing.

        Arguments:
            event -- the close event
        """
        self.dialogShown.emit(False)


class ConditionRule(QGroupBox):
    """Group boxes for conditional rules in the ConditionDialog.
    """
    def __init__(self, num, fieldNames, parent=None):
        """Create the conditional rule group box.

        Arguments:
            num -- the sequence number for the title
            fieldNames -- a list of available field names
            parent -- the parent dialog
        """
        super().__init__(parent)
        self.fieldNames = fieldNames
        self.setTitle(_('Rule {0}').format(num))
        layout = QHBoxLayout(self)
        self.fieldBox = QComboBox()
        self.fieldBox.setEditable(False)
        self.fieldBox.addItems(fieldNames)
        layout.addWidget(self.fieldBox)

        self.operBox = QComboBox()
        self.operBox.setEditable(False)
        self.operBox.addItems([_(op) for op in _operators])
        layout.addWidget(self.operBox)
        self.operBox.currentIndexChanged.connect(self.changeOper)

        self.editor = QLineEdit()
        layout.addWidget(self.editor)
        self.fieldBox.setFocus()

    def reloadFieldBox(self, fieldNames, currentField=''):
        """Load the field combo box with a new field list.

        Arguments:
            fieldNames -- list of field names to add
            currentField -- a field name to make current if given
        """
        self.fieldNames = fieldNames
        self.fieldBox.clear()
        self.fieldBox.addItems(fieldNames)
        if currentField:
            fieldNum = fieldNames.index(currentField)
            self.fieldBox.setCurrentIndex(fieldNum)
        self.changeOper()

    def setCondition(self, conditionLine):
        """Set values to match the given condition.

        Arguments:
            conditionLine -- the ConditionLine to match
        """
        fieldNum = self.fieldNames.index(conditionLine.fieldName)
        self.fieldBox.setCurrentIndex(fieldNum)
        operNum = _operators.index(conditionLine.oper)
        self.operBox.setCurrentIndex(operNum)
        self.editor.setText(conditionLine.value)

    def conditionLine(self):
        """Return a conditionLine for the current settings.
        """
        operTransDict = dict([(_(name), name) for name in _operators])
        oper = operTransDict[self.operBox.currentText()]
        return ConditionLine('and', self.fieldBox.currentText(), oper,
                             self.editor.text())

    def changeOper(self):
        """Set the field available based on an operator change.
        """
        realOp = self.operBox.currentText() not in (_(op) for op in
                                                       ('True', 'False'))
        self.editor.setEnabled(realOp)
        if (not realOp and
            self.parent().typeCombo.currentText() == _allTypeEntry):
            realOp = True
        self.fieldBox.setEnabled(realOp)


class SmallListWidget(QListWidget):
    """ListWidget with a smaller size hint.
    """
    def __init__(self, parent=None):
        """Initialize the widget.

        Arguments:
            parent -- the parent, if given
        """
        super().__init__(parent)

    def sizeHint(self):
        """Return smaller height.
        """
        if self.count():
            rowHeight = self.sizeHintForRow(0)
        else:
            self.addItem('tmp')
            rowHeight = self.sizeHintForRow(0)
            self.takeItem(0)
        newHeight = rowHeight * 3 + self.frameWidth() * 2
        return QSize(super().sizeHint().width(), newHeight)