# -*- coding: utf-8 -*-

# Copyright (c) 2016 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing a search and replace widget for the hex editor.
"""

from __future__ import unicode_literals
try:
    str = unicode       # __IGNORE_EXCEPTION__
except NameError:
    pass

from PyQt5.QtCore import pyqtSlot, Qt, QByteArray, QRegExp
from PyQt5.QtGui import QRegExpValidator
from PyQt5.QtWidgets import QWidget

from E5Gui.E5Action import E5Action
from E5Gui import E5MessageBox

import UI.PixmapCache


class HexEditSearchReplaceWidget(QWidget):
    """
    Class implementing a search and replace widget for the hex editor.
    """
    def __init__(self, editor, mainWindow, replace=False, parent=None):
        """
        Constructor
        
        @param editor reference to the hex editor widget
        @type HexEditWidget
        @param mainWindow reference to the main window
        @type HexEditMainWindow
        @param replace flag indicating a replace widget
        @type bool
        @param parent reference to the parent widget
        @type QWidget
        """
        super(HexEditSearchReplaceWidget, self).__init__(parent)
        
        self.__replace = replace
        self.__editor = editor
        
        # keep this in sync with the logic in __getContent()
        self.__formatAndValidators = {
            "hex": (self.tr("Hex"), QRegExpValidator((QRegExp("[0-9a-f]*")))),
            "dec": (self.tr("Dec"), QRegExpValidator((QRegExp("[0-9]*")))),
            "oct": (self.tr("Oct"), QRegExpValidator((QRegExp("[0-7]*")))),
            "bin": (self.tr("Bin"), QRegExpValidator((QRegExp("[01]*")))),
            "iso-8859-1": (self.tr("Text"), None),
            # text as latin-1/iso-8859-1
            "utf-8": (self.tr("UTF-8"), None),
            # text as utf-8
        }
        formatOrder = ["hex", "dec", "oct", "bin", "iso-8859-1", "utf-8"]
        
        self.__currentFindFormat = ""
        self.__currentReplaceFormat = ""
        
        self.__findHistory = mainWindow.getSRHistory("search")
        if replace:
            from .Ui_HexEditReplaceWidget import Ui_HexEditReplaceWidget
            self.__replaceHistory = mainWindow.getSRHistory("replace")
            self.__ui = Ui_HexEditReplaceWidget()
        else:
            from .Ui_HexEditSearchWidget import Ui_HexEditSearchWidget
            self.__ui = Ui_HexEditSearchWidget()
        self.__ui.setupUi(self)
        
        self.__ui.closeButton.setIcon(UI.PixmapCache.getIcon("close.png"))
        self.__ui.findPrevButton.setIcon(
            UI.PixmapCache.getIcon("1leftarrow.png"))
        self.__ui.findNextButton.setIcon(
            UI.PixmapCache.getIcon("1rightarrow.png"))
        
        if replace:
            self.__ui.replaceButton.setIcon(
                UI.PixmapCache.getIcon("editReplace.png"))
            self.__ui.replaceSearchButton.setIcon(
                UI.PixmapCache.getIcon("editReplaceSearch.png"))
            self.__ui.replaceAllButton.setIcon(
                UI.PixmapCache.getIcon("editReplaceAll.png"))
        
        for format in formatOrder:
            formatStr, validator = self.__formatAndValidators[format]
            self.__ui.findFormatCombo.addItem(formatStr, format)
        if replace:
            for format in formatOrder:
                formatStr, validator = self.__formatAndValidators[format]
                self.__ui.replaceFormatCombo.addItem(formatStr, format)
        
        self.__ui.findtextCombo.setCompleter(None)
        self.__ui.findtextCombo.lineEdit().returnPressed.connect(
            self.__findByReturnPressed)
        if replace:
            self.__ui.replacetextCombo.setCompleter(None)
            self.__ui.replacetextCombo.lineEdit().returnPressed.connect(
                self.on_replaceButton_clicked)
        
        self.findNextAct = E5Action(
            self.tr('Find Next'),
            self.tr('Find Next'),
            0, 0, self, 'hexEditor_search_widget_find_next')
        self.findNextAct.triggered.connect(self.on_findNextButton_clicked)
        self.findNextAct.setEnabled(False)
        self.__ui.findtextCombo.addAction(self.findNextAct)
        
        self.findPrevAct = E5Action(
            self.tr('Find Prev'),
            self.tr('Find Prev'),
            0, 0, self, 'hexEditor_search_widget_find_prev')
        self.findPrevAct.triggered.connect(self.on_findPrevButton_clicked)
        self.findPrevAct.setEnabled(False)
        self.__ui.findtextCombo.addAction(self.findPrevAct)
        
        self.__havefound = False
    
    @pyqtSlot(int)
    def on_findFormatCombo_currentIndexChanged(self, idx):
        """
        Private slot to handle a selection from the find format.
        
        @param idx index of the selected entry
        @type int
        """
        if idx >= 0:
            format = self.__ui.findFormatCombo.itemData(idx)
            
            if format != self.__currentFindFormat:
                txt = self.__ui.findtextCombo.currentText()
                newTxt = self.__convertText(
                    txt, self.__currentFindFormat, format)
                self.__currentFindFormat = format
                
                self.__ui.findtextCombo.setValidator(
                    self.__formatAndValidators[format][1])
                
                self.__ui.findtextCombo.setEditText(newTxt)
    
    @pyqtSlot(str)
    def on_findtextCombo_editTextChanged(self, txt):
        """
        Private slot to enable/disable the find buttons.
        
        @param txt text of the find text combo
        @type str
        """
        if not txt:
            self.__ui.findNextButton.setEnabled(False)
            self.findNextAct.setEnabled(False)
            self.__ui.findPrevButton.setEnabled(False)
            self.findPrevAct.setEnabled(False)
            if self.__replace:
                self.__ui.replaceButton.setEnabled(False)
                self.__ui.replaceSearchButton.setEnabled(False)
                self.__ui.replaceAllButton.setEnabled(False)
        else:
            self.__ui.findNextButton.setEnabled(True)
            self.findNextAct.setEnabled(True)
            self.__ui.findPrevButton.setEnabled(True)
            self.findPrevAct.setEnabled(True)
            if self.__replace:
                self.__ui.replaceButton.setEnabled(False)
                self.__ui.replaceSearchButton.setEnabled(False)
                self.__ui.replaceAllButton.setEnabled(True)
    
    @pyqtSlot(int)
    def on_findtextCombo_activated(self, idx):
        """
        Private slot to handle a selection from the find history.
        
        @param idx index of the selected entry
        @type int
        """
        if idx >= 0:
            formatIndex = self.__ui.findtextCombo.itemData(idx)
            if formatIndex is not None:
                self.__ui.findFormatCombo.setCurrentIndex(formatIndex)
    
    def __getContent(self, replace=False):
        """
        Private method to get the contents of the find/replace combo as
        a bytearray.
        
        @param replace flag indicating to retrieve the replace contents
        @type bool
        @return search or replace term as text and binary data
        @rtype tuple of bytearray and str
        """
        if replace:
            textCombo = self.__ui.replacetextCombo
            formatCombo = self.__ui.replaceFormatCombo
            history = self.__replaceHistory
        else:
            textCombo = self.__ui.findtextCombo
            formatCombo = self.__ui.findFormatCombo
            history = self.__findHistory
        
        txt = textCombo.currentText()
        idx = formatCombo.currentIndex()
        format = formatCombo.itemData(idx)
        ba = self.__text2bytearray(txt, format)
        
        # This moves any previous occurrence of this statement to the head
        # of the list and updates the combobox
        historyEntry = (idx, txt)
        if historyEntry in history:
            history.remove(historyEntry)
        history.insert(0, historyEntry)
        textCombo.clear()
        for index, text in history:
            textCombo.addItem(text, index)
        
        return ba, txt
    
    @pyqtSlot()
    def on_findNextButton_clicked(self):
        """
        Private slot to find the next occurrence.
        """
        self.findPrevNext(False)
    
    @pyqtSlot()
    def on_findPrevButton_clicked(self):
        """
        Private slot to find the previous occurrence.
        """
        self.findPrevNext(True)
    
    def findPrevNext(self, prev=False):
        """
        Public slot to find the next occurrence of the search term.
        
        @param prev flag indicating a backwards search
        @type bool
        @return flag indicating a successful search
        @rtype bool
        """
        if not self.__havefound or not self.__ui.findtextCombo.currentText():
            self.show()
            return
        
        self.__findBackwards = prev
        ba, txt = self.__getContent()
        
        idx = -1
        if len(ba) > 0:
            startIndex = self.__editor.cursorPosition() // 2
            if prev:
                if self.__editor.hasSelection() and \
                        startIndex == self.__editor.getSelectionEnd():
                    # skip to the selection start
                    startIndex = self.__editor.getSelectionBegin()
                idx = self.__editor.lastIndexOf(ba, startIndex)
            else:
                if self.__editor.hasSelection() and \
                        startIndex == self.__editor.getSelectionBegin() - 1:
                    # skip to the selection end
                    startIndex = self.__editor.getSelectionEnd()
                idx = self.__editor.indexOf(ba, startIndex)
        
        if idx >= 0:
            if self.__replace:
                self.__ui.replaceButton.setEnabled(True)
                self.__ui.replaceSearchButton.setEnabled(True)
        else:
            E5MessageBox.information(
                self, self.windowTitle(),
                self.tr("'{0}' was not found.").format(txt))
        
        return idx >= 0
    
    def __findByReturnPressed(self):
        """
        Private slot to handle a return pressed in the find combo.
        """
        if self.__findBackwards:
            self.findPrevNext(True)
        else:
            self.findPrevNext(False)
    
    @pyqtSlot(int)
    def on_replaceFormatCombo_currentIndexChanged(self, idx):
        """
        Private slot to handle a selection from the replace format.
        
        @param idx index of the selected entry
        @type int
        """
        if idx >= 0:
            format = self.__ui.replaceFormatCombo.itemData(idx)
            
            if format != self.__currentReplaceFormat:
                txt = self.__ui.replacetextCombo.currentText()
                newTxt = self.__convertText(
                    txt, self.__currentReplaceFormat, format)
                self.__currentReplaceFormat = format
                
                self.__ui.replacetextCombo.setValidator(
                    self.__formatAndValidators[format][1])
                
                self.__ui.replacetextCombo.setEditText(newTxt)
    
    @pyqtSlot(int)
    def on_replacetextCombo_activated(self, idx):
        """
        Private slot to handle a selection from the replace history.
        
        @param idx index of the selected entry
        @type int
        """
        if idx >= 0:
            formatIndex = self.__ui.replacetextCombo.itemData(idx)
            if formatIndex is not None:
                self.__ui.replaceFormatCombo.setCurrentIndex(formatIndex)

    @pyqtSlot()
    def on_replaceButton_clicked(self):
        """
        Private slot to replace one occurrence of data.
        """
        self.__doReplace(False)
    
    @pyqtSlot()
    def on_replaceSearchButton_clicked(self):
        """
        Private slot to replace one occurrence of data and search for the next
        one.
        """
        self.__doReplace(True)
    
    def __doReplace(self, searchNext):
        """
        Private method to replace one occurrence of data.
        
        @param searchNext flag indicating to search for the next occurrence
        @type bool
        """
        # Check enabled status due to dual purpose usage of this method
        if not self.__ui.replaceButton.isEnabled() and \
           not self.__ui.replaceSearchButton.isEnabled():
            return
        
        fba, ftxt = self.__getContent(False)
        rba, rtxt = self.__getContent(True)
        
        ok = False
        if self.__editor.hasSelection():
            # we did a successful search before
            startIdx = self.__editor.getSelectionBegin()
            self.__editor.replaceByteArray(startIdx, len(fba), rba)
            
            if searchNext:
                ok = self.findPrevNext(self.__findBackwards)
        
        if not ok:
            self.__ui.replaceButton.setEnabled(False)
            self.__ui.replaceSearchButton.setEnabled(False)
    
    @pyqtSlot()
    def on_replaceAllButton_clicked(self):
        """
        Private slot to replace all occurrences of data.
        """
        replacements = 0
        
        cursorPosition = self.__editor.cursorPosition()
        
        fba, ftxt = self.__getContent(False)
        rba, rtxt = self.__getContent(True)
        
        idx = 0
        while idx >= 0:
            idx = self.__editor.indexOf(fba, idx)
            if idx >= 0:
                self.__editor.replaceByteArray(idx, len(fba), rba)
                idx += len(rba)
                replacements += 1
        
        if replacements:
            E5MessageBox.information(
                self, self.windowTitle(),
                self.tr("Replaced {0} occurrences.")
                .format(replacements))
        else:
            E5MessageBox.information(
                self, self.windowTitle(),
                self.tr("Nothing replaced because '{0}' was not found.")
                .format(ftxt))
        
        self.__editor.setCursorPosition(cursorPosition)
        self.__editor.ensureVisible()
    
    def __showFind(self, text=''):
        """
        Private method to display this widget in find mode.
        
        @param text hex encoded text to be shown in the findtext edit
        @type str
        """
        self.__replace = False
        
        self.__ui.findtextCombo.clear()
        for index, txt in self.__findHistory:
            self.__ui.findtextCombo.addItem(txt, index)
        self.__ui.findFormatCombo.setCurrentIndex(0)    # 0 is always Hex
        self.on_findFormatCombo_currentIndexChanged(0)
        self.__ui.findtextCombo.setEditText(text)
        self.__ui.findtextCombo.lineEdit().selectAll()
        self.__ui.findtextCombo.setFocus()
        self.on_findtextCombo_editTextChanged(text)
        
        self.__havefound = True
        self.__findBackwards = False
    
    def __showReplace(self, text=''):
        """
        Private slot to display this widget in replace mode.
        
        @param text hex encoded text to be shown in the findtext edit
        @type str
        """
        self.__replace = True
        
        self.__ui.findtextCombo.clear()
        for index, txt in self.__findHistory:
            self.__ui.findtextCombo.addItem(txt, index)
        self.__ui.findFormatCombo.setCurrentIndex(0)    # 0 is always Hex
        self.on_findFormatCombo_currentIndexChanged(0)
        self.__ui.findtextCombo.setEditText(text)
        self.__ui.findtextCombo.lineEdit().selectAll()
        self.__ui.findtextCombo.setFocus()
        self.on_findtextCombo_editTextChanged(text)
        
        self.__ui.replacetextCombo.clear()
        for index, txt in self.__replaceHistory:
            self.__ui.replacetextCombo.addItem(txt, index)
        self.__ui.replaceFormatCombo.setCurrentIndex(0)    # 0 is always Hex
        self.on_replaceFormatCombo_currentIndexChanged(0)
        self.__ui.replacetextCombo.setEditText('')
        
        self.__havefound = True
        self.__findBackwards = False
    
    def show(self, text=''):
        """
        Public slot to show the widget.
        
        @param text hex encoded text to be shown in the findtext edit
        @type str
        """
        if self.__replace:
            self.__showReplace(text)
        else:
            self.__showFind(text)
        super(HexEditSearchReplaceWidget, self).show()
        self.activateWindow()
    
    @pyqtSlot()
    def on_closeButton_clicked(self):
        """
        Private slot to close the widget.
        """
        self.__editor.setFocus(Qt.OtherFocusReason)
        self.close()

    def keyPressEvent(self, event):
        """
        Protected slot to handle key press events.
        
        @param event reference to the key press event
        @type QKeyEvent
        """
        if event.key() == Qt.Key_Escape:
            self.close()
    
    def __convertText(self, txt, oldFormat, newFormat):
        """
        Private method to convert text from one format into another.
        
        @param txt text to be converted
        @type str
        @param oldFormat current format of the text
        @type str
        @param newFormat format to convert to
        @type str
        @return converted text
        @rtype str
        """
        if txt and oldFormat and newFormat and oldFormat != newFormat:
            # step 1: convert the text to a byte array using the old format
            byteArray = self.__text2bytearray(txt, oldFormat)
            
            # step 2: convert the byte array to text using the new format
            txt = self.__bytearray2text(byteArray, newFormat)
        
        return txt
    
    def __int2bytearray(self, value):
        """
        Private method to convert an integer to a byte array.
        
        @param value value to be converted
        @type int
        @return byte array for the given value
        @rtype bytearray
        """
        ba = bytearray()
        while value > 0:
            value, modulus = divmod(value, 256)
            ba.insert(0, modulus)
        
        return ba
    
    def __bytearray2int(self, array):
        """
        Private method to convert a byte array to an integer value.
        
        @param array byte array to be converted
        @type bytearray
        @return integer value of the given array
        @rtype int
        """
        value = 0
        for b in array:
            value = value * 256 + b
        
        return value
    
    def __text2bytearray(self, txt, format):
        """
        Private method to convert a text to a byte array.
        
        @param txt text to be converted
        @type str
        @param format format of the text
        @type str
        @return converted text
        @rtype bytearray
        """
        assert format in self.__formatAndValidators.keys()
        
        if format == "hex":             # hex format
            ba = bytearray(QByteArray.fromHex(
                bytes(txt, encoding="ascii")))
        elif format == "dec":           # decimal format
            ba = self.__int2bytearray(int(txt, 10))
        elif format == "oct":           # octal format
            ba = self.__int2bytearray(int(txt, 8))
        elif format == "bin":           # binary format
            ba = self.__int2bytearray(int(txt, 2))
        elif format == "iso-8859-1":    # latin-1/iso-8859-1 text
            ba = bytearray(txt, encoding="iso-8859-1")
        elif format == "utf-8":         # utf-8 text
            ba = bytearray(txt, encoding="utf-8")
        
        return ba
    
    def __bytearray2text(self, array, format):
        """
        Private method to convert a byte array to a text.
        
        @param array byte array to be converted
        @type bytearray
        @param format format of the text
        @type str
        @return formatted text
        @rtype str
        """
        assert format in self.__formatAndValidators.keys()
        
        if format == "hex":             # hex format
            txt = "{0:x}".format(self.__bytearray2int(array))
        elif format == "dec":           # decimal format
            txt = "{0:d}".format(self.__bytearray2int(array))
        elif format == "oct":           # octal format
            txt = "{0:o}".format(self.__bytearray2int(array))
        elif format == "bin":           # binary format
            txt = "{0:b}".format(self.__bytearray2int(array))
        elif format == "iso-8859-1":    # latin-1/iso-8859-1 text
            txt = str(array, encoding="iso-8859-1")
        elif format == "utf-8":         # utf-8 text
            txt = str(array, encoding="utf-8", errors="replace")
        
        return txt
