chordsheet/gui.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Wed May 29 00:02:24 2019

@author: ivan
"""

import sys
import fitz
import io
import subprocess
import os
import time
from copy import copy

from PyQt5.QtWidgets import QApplication, QAction, QLabel, QDialogButtonBox, QDialog, QFileDialog, QMessageBox, QPushButton, QLineEdit, QCheckBox, QFontComboBox, QSpinBox, QDoubleSpinBox, QTableWidgetItem, QTabWidget, QComboBox, QWidget, QScrollArea, QMainWindow, QShortcut, QMdiSubWindow
from PyQt5.QtCore import QFile, QObject, Qt, pyqtSlot, QSettings
from PyQt5.QtGui import QPixmap, QImage, QKeySequence, QFontInfo, QFont, QRawFont
from PyQt5 import uic
from chordsheet.tableView import ChordTableView, BlockTableView
from chordsheet.comboBox import MComboBox
from chordsheet.pdfViewer import PDFViewer

from reportlab.lib.units import mm, cm, inch, pica
from reportlab.lib.pagesizes import A4, A5, LETTER, LEGAL
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont

from chordsheet.common import scriptDir
from chordsheet.document import Document, Style, Chord, Block, Section
from chordsheet.render import Renderer
from chordsheet.parsers import parseFingering, parseName
from chordsheet.messageBox import UnsavedMessageBox, UnreadableMessageBox, ChordNameWarningMessageBox, SectionNameWarningMessageBox, BlockMustHaveSectionWarningMessageBox, VoicingWarningMessageBox, LengthWarningMessageBox
from chordsheet.dialogs import GuitarDialog, AboutDialog
from chordsheet.panels import DocInfoDockWidget, PageSetupDockWidget, ChordsDockWidget, SectionsDockWidget, BlocksDockWidget, PreviewDockWidget

import _version

# enable automatic high DPI scaling on Windows
QApplication.setAttribute(Qt.AA_EnableHighDpiScaling, True)
QApplication.setOrganizationName("Ivan Holmes")
QApplication.setOrganizationDomain("ivanholmes.co.uk")
QApplication.setApplicationName("Chordsheet")
settings = QSettings()

pdfmetrics.registerFont(
    TTFont('FreeSans', os.path.join(scriptDir, 'fonts', 'FreeSans.ttf')))
if sys.platform == "darwin":
    pdfmetrics.registerFont(
        TTFont('HelveticaNeue', 'HelveticaNeue.ttc', subfontIndex=0))

# dictionaries for combo boxes
pageSizeDict = {'A4': A4, 'A5': A5, 'Letter': LETTER, 'Legal': LEGAL}
# point is 1 because reportlab's native unit is points.
unitDict = {'mm': mm, 'cm': cm, 'inch': inch, 'point': 1, 'pica': pica}


class MainWindow(QMainWindow):
    """
    Class for the main window of the application.
    """

    def __init__(self, filename=None):
        """
        Initialisation function for the main window of the application.

        Arguments:
        doc -- the Document object for the window to use
        style -- the Style object for the window to use
        """
        super().__init__()

        self.UIFileLoader(str(os.path.join(scriptDir, 'ui', 'new.ui')))

        self.setCentralWidget(self.window.centralWidget)
        self.setMenuBar(self.window.menuBar)
        self.setWindowTitle("Chordsheet")
        
        self.lastSubWindow = None
        self.currentSection = None

        if filename:
            try:
                self.openFile(filename)
            except Exception:
                UnreadableMessageBox().exec()

    def closeEvent(self, event):
        """
        Reimplement the built in closeEvent to allow asking the user to save.
        """
        if not self.window.mdiArea.subWindowList():
            self.close()

    def UIFileLoader(self, ui_file):
        """
        Loads the .ui file for this window and connects the UI elements to their actions.
        """
        ui_file = QFile(ui_file)
        ui_file.open(QFile.ReadOnly)

        self.window = uic.loadUi(ui_file)
        ui_file.close()
        
        self.docinfo = DocInfoDockWidget()
        self.psetup = PageSetupDockWidget()
        self.chordsw = ChordsDockWidget()
        self.sectionsw = SectionsDockWidget()
        self.blocksw = BlocksDockWidget()
        self.previeww = PreviewDockWidget()
        
        self.addDockWidget(Qt.LeftDockWidgetArea, self.docinfo)
        self.addDockWidget(Qt.LeftDockWidgetArea, self.psetup)
        self.addDockWidget(Qt.LeftDockWidgetArea, self.previeww)
        self.addDockWidget(Qt.RightDockWidgetArea, self.chordsw)
        self.addDockWidget(Qt.RightDockWidgetArea, self.sectionsw)
        self.addDockWidget(Qt.RightDockWidgetArea, self.blocksw)

        # Check all the boxes in the window menu
        self.window.actionDocument_information.setChecked(True)
        self.window.actionPage_setup.setChecked(True)
        self.window.actionChords.setChecked(True)
        self.window.actionSections.setChecked(True)
        self.window.actionBlocks.setChecked(True)
        self.window.actionPreview.setChecked(True)
        
        # link all the UI elements
        self.window.mdiArea.subWindowActivated.connect(self.switchDocument)
        
        self.window.actionAbout.triggered.connect(self.menuFileAboutAction)
        self.window.actionNew.triggered.connect(self.menuFileNewAction)
        self.window.actionOpen.triggered.connect(self.menuFileOpenAction)
        self.window.actionSave.triggered.connect(self.menuFileSaveAction)
        self.window.actionSave_as.triggered.connect(self.menuFileSaveAsAction)
        self.window.actionSave_PDF.triggered.connect(
            self.menuFileSavePDFAction)
        self.window.actionPrint.triggered.connect(self.menuFilePrintAction)
        self.window.actionClose.triggered.connect(self.menuFileCloseAction)
        self.window.actionUndo.triggered.connect(self.menuEditUndoAction)
        self.window.actionRedo.triggered.connect(self.menuEditRedoAction)
        self.window.actionCut.triggered.connect(self.menuEditCutAction)
        self.window.actionCopy.triggered.connect(self.menuEditCopyAction)
        self.window.actionPaste.triggered.connect(self.menuEditPasteAction)

        self.window.actionNew.setShortcut(QKeySequence.New)
        self.window.actionOpen.setShortcut(QKeySequence.Open)
        self.window.actionSave.setShortcut(QKeySequence.Save)
        self.window.actionSave_as.setShortcut(QKeySequence.SaveAs)
        self.window.actionSave_PDF.setShortcut(QKeySequence("Ctrl+E"))
        self.window.actionPrint.setShortcut(QKeySequence.Print)
        self.window.actionClose.setShortcut(QKeySequence.Close)
        self.window.actionUndo.setShortcut(QKeySequence.Undo)
        self.window.actionRedo.setShortcut(QKeySequence.Redo)
        self.window.actionCut.setShortcut(QKeySequence.Cut)
        self.window.actionCopy.setShortcut(QKeySequence.Copy)
        self.window.actionPaste.setShortcut(QKeySequence.Paste)

        self.window.actionDocument_information.triggered.connect(self.menuWindowDocInfoAction)
        self.window.actionPage_setup.triggered.connect(self.menuWindowPageSetupAction)
        self.window.actionChords.triggered.connect(self.menuWindowChordsAction)
        self.window.actionSections.triggered.connect(self.menuWindowSectionsAction)
        self.window.actionBlocks.triggered.connect(self.menuWindowBlocksAction)
        self.window.actionPreview.triggered.connect(self.menuWindowPreviewAction)


        self.psetup.widget().pageSizeComboBox.currentIndexChanged.connect(
            self.pageSizeAction)
        self.psetup.widget().documentUnitsComboBox.currentIndexChanged.connect(
            self.unitAction)
            
        self.psetup.widget().pageSizeComboBox.addItems(list(pageSizeDict.keys()))
        self.psetup.widget().pageSizeComboBox.setCurrentText(
            list(pageSizeDict.keys())[0])

        self.psetup.widget().documentUnitsComboBox.addItems(list(unitDict.keys()))
        self.psetup.widget().documentUnitsComboBox.setCurrentText(
            list(unitDict.keys())[0])
        
        self.psetup.widget().fontComboBox.currentFontChanged.connect(self.fontChangeAction)
        self.psetup.widget().includedFontCheckBox.stateChanged.connect(
            self.includedFontAction)

        self.previeww.widget().updatePreviewButton.clicked.connect(self.generateAction)

        # update whole document when any tab is selected
        # self.window.tabWidget.tabBarClicked.connect(self.tabBarUpdateAction)

        self.chordsw.widget().guitarVoicingButton.clicked.connect(
            self.guitarVoicingAction)
        self.chordsw.widget().addChordButton.clicked.connect(self.addChordAction)
        self.chordsw.widget().removeChordButton.clicked.connect(self.removeChordAction)
        self.chordsw.widget().updateChordButton.clicked.connect(self.updateChordAction)

        # connecting clicked only works for this combo box because it's my own modified version (MComboBox)
        self.blocksw.widget().blockSectionComboBox.clicked.connect(
            self.blockSectionClickedAction)
        self.blocksw.widget().blockSectionComboBox.currentIndexChanged.connect(
            self.blockSectionChangedAction)
        self.blocksw.widget().addBlockButton.clicked.connect(self.addBlockAction)
        self.blocksw.widget().removeBlockButton.clicked.connect(self.removeBlockAction)
        self.blocksw.widget().updateBlockButton.clicked.connect(self.updateBlockAction)

        self.sectionsw.widget().addSectionButton.clicked.connect(self.addSectionAction)
        self.sectionsw.widget().removeSectionButton.clicked.connect(
            self.removeSectionAction)
        self.sectionsw.widget().updateSectionButton.clicked.connect(
            self.updateSectionAction)

        self.chordsw.widget().chordTableView.clicked.connect(self.chordClickedAction)
        self.sectionsw.widget().sectionTableView.clicked.connect(self.sectionClickedAction)
        self.blocksw.widget().blockTableView.clicked.connect(self.blockClickedAction)

        # Set the tab widget to Overview tab
        # self.window.tabWidget.setCurrentIndex(0)

    def UIInitDocument(self, doc):
        """
        Fills the window's fields with the values from its document.
        """
        # self.updateTitleBar()

        # set all fields to appropriate values from document
        self.docinfo.widget().titleLineEdit.setText(doc.title)
        self.docinfo.widget().subtitleLineEdit.setText(doc.subtitle)
        self.docinfo.widget().composerLineEdit.setText(doc.composer)
        self.docinfo.widget().arrangerLineEdit.setText(doc.arranger)
        self.docinfo.widget().timeSignatureSpinBox.setValue(doc.timeSignature)
        self.docinfo.widget().tempoLineEdit.setText(doc.tempo)

        self.chordsw.widget().chordTableView.populate(doc.chordList)
        self.sectionsw.widget().sectionTableView.populate(doc.sectionList)
        
        self.updateChordDict(doc)
        self.updateSectionDict(doc)
        # populate the block table with the first section, account for a document with no sections
        if self.currentSection is None:
            self.currentSection = doc.sectionList[0] if doc.sectionList else None
        else:
            self.blocksw.widget().blockSectionComboBox.setCurrentText(
                    self.currentSection.name)
        self.blocksw.widget().blockTableView.populate(
            self.currentSection.blockList if self.currentSection else [])

    def UIInitStyle(self, style):
        """
        Fills the window's fields with the values from its style.
        """
        self.psetup.widget().pageSizeComboBox.setCurrentText(
            [k for k, v in pageSizeDict.items() if v==style.pageSize][0])

        self.psetup.widget().documentUnitsComboBox.setCurrentText(
            [k for k, v in unitDict.items() if v==style.unit][0])

        self.psetup.widget().lineSpacingDoubleSpinBox.setValue(style.lineSpacing)

        self.psetup.widget().leftMarginLineEdit.setText(str(style.leftMargin))
        self.psetup.widget().rightMarginLineEdit.setText(str(style.rightMargin))
        self.psetup.widget().topMarginLineEdit.setText(str(style.topMargin))
        self.psetup.widget().bottomMarginLineEdit.setText(str(style.bottomMargin))

        # self.psetup.widget().fontComboBox.setDisabled(True)
        self.psetup.widget().includedFontCheckBox.setChecked(True)

        self.psetup.widget().beatWidthLineEdit.setText(str(style.unitWidth))
        
    def updateChordDict(self, doc):
        """
        Updates the dictionary used to generate the Chord menu (on the block tab)
        """
        self.chordDict = {'None': None}
        self.chordDict.update({c.name: c for c in doc.chordList})
        self.blocksw.widget().blockChordComboBox.clear()
        self.blocksw.widget().blockChordComboBox.addItems(list(self.chordDict.keys()))
        
    def updateSectionDict(self, doc):
        """
        Updates the dictionary used to generate the Section menu (on the block tab)
        """
        self.sectionDict = {s.name: s for s in doc.sectionList}
        self.blocksw.widget().blockSectionComboBox.clear()
        self.blocksw.widget().blockSectionComboBox.addItems(
            list(self.sectionDict.keys()))
            
    def fontChangeAction(self):
        if self.window.mdiArea.currentSubWindow() is not None:
            qFont = self.psetup.widget().fontComboBox.currentFont()
            qFontReal = QRawFont.fromFont(qFont)
            #fontInfo = QFontInfo(qFont)
            #qFontReal = QRawFont(fontInfo.family())
            print(qFont.rawName())
            
        
    def switchDocument(self, curWindow):
        if curWindow is not None:
            if self.lastSubWindow is not None:
                self.lastSubWindow.currentSection = self.currentSection
                             
            self.UIInitDocument(curWindow.doc)
            self.UIInitStyle(curWindow.style)
            self.currentSection = curWindow.currentSection
            if self.currentSection is not None:
                self.blocksw.widget().blockSectionComboBox.setCurrentText(
                    self.currentSection.name)
            self.lastSubWindow = curWindow
        
    def generateAction(self):
        if self.window.mdiArea.currentSubWindow() is not None:
            self.window.mdiArea.currentSubWindow().updateDocument()
            self.window.mdiArea.currentSubWindow().updatePreview()
        
    def removeChordAction(self):
        if self.chordsw.widget().chordTableView.selectionModel().hasSelection():  #  check for selection
            self.window.mdiArea.currentSubWindow().updateChords()

            row = self.chordsw.widget().chordTableView.selectionModel().currentIndex().row()
            oldName = self.chordsw.widget().chordTableView.model.item(row, 0).text()
            self.window.mdiArea.currentSubWindow().doc.chordList.pop(row)

            self.chordsw.widget().chordTableView.populate(self.window.mdiArea.currentSubWindow().doc.chordList)
            # remove the chord if any of the blocks have it attached
            if self.currentSection is not None:
                for s in self.window.mdiArea.currentSubWindow().doc.sectionList:
                        for b in s.blockList:
                            if b.chord:
                                if b.chord.name == oldName:
                                    b.chord = None
                self.blocksw.widget().blockTableView.populate(self.currentSection.blockList)
            self.clearChordLineEdits()
            self.updateChordDict(self.window.mdiArea.currentSubWindow().doc)

    def addChordAction(self):
        success = False  # initialise
        self.window.mdiArea.currentSubWindow().updateChords()

        cName = parseName(self.chordsw.widget().chordNameLineEdit.text())
        if cName:
            self.window.mdiArea.currentSubWindow().doc.chordList.append(Chord(cName))
            if self.chordsw.widget().guitarVoicingLineEdit.text() or self.chordsw.widget().pianoVoicingLineEdit.text():
                if self.chordsw.widget().guitarVoicingLineEdit.text():
                    try:
                        self.window.mdiArea.currentSubWindow().doc.chordList[-1].voicings['guitar'] = parseFingering(
                            self.chordsw.widget().guitarVoicingLineEdit.text(), 'guitar')
                        success = True  #  chord successfully parsed
                    except Exception:
                        VoicingWarningMessageBox().exec()  # Voicing is malformed,  warn user
                if self.chordsw.widget().pianoVoicingLineEdit.text():
                    try:
                        self.window.mdiArea.currentSubWindow().doc.chordList[-1].voicings['piano'] = parseFingering(
                            self.chordsw.widget().pianoVoicingLineEdit.text(), 'piano')
                        success = True  #  chord successfully parsed
                    except Exception:
                        VoicingWarningMessageBox().exec()  # Voicing is malformed,  warn user
            else:
                success = True  #  chord successfully parsed
        else:
            ChordNameWarningMessageBox().exec()  # Chord has no name, warn user

        if success == True:  # if chord was parsed properly
            self.chordsw.widget().chordTableView.populate(self.window.mdiArea.currentSubWindow().doc.chordList)
            self.clearChordLineEdits()
            self.updateChordDict(self.window.mdiArea.currentSubWindow().doc)

    def updateChordAction(self):
        success = False  # see comments above
        if self.chordsw.widget().chordTableView.selectionModel().hasSelection():  #  check for selection
            self.window.mdiArea.currentSubWindow().updateChords()
            row = self.chordsw.widget().chordTableView.selectionModel().currentIndex().row()
            oldName = self.chordsw.widget().chordTableView.model.item(row, 0).text()
            cName = parseName(self.chordsw.widget().chordNameLineEdit.text())
            if cName:
                self.window.mdiArea.currentSubWindow().doc.chordList[row].name = cName
                if self.chordsw.widget().guitarVoicingLineEdit.text() or self.chordsw.widget().pianoVoicingLineEdit.text():
                    if self.chordsw.widget().guitarVoicingLineEdit.text():
                        try:
                            self.window.mdiArea.currentSubWindow().doc.chordList[row].voicings['guitar'] = parseFingering(
                                self.chordsw.widget().guitarVoicingLineEdit.text(), 'guitar')
                            success = True  #  chord successfully parsed
                        except Exception:
                            VoicingWarningMessageBox().exec()  # Voicing is malformed,  warn user
                    if self.chordsw.widget().pianoVoicingLineEdit.text():
                        try:
                            self.window.mdiArea.currentSubWindow().doc.chordList[row].voicings['piano'] = parseFingering(
                                self.chordsw.widget().pianoVoicingLineEdit.text(), 'piano')
                            success = True  #  chord successfully parsed
                        except Exception:
                            VoicingWarningMessageBox().exec()  # Voicing is malformed,  warn user
                else:
                    success = True  #  chord successfully parsed
            else:
                ChordNameWarningMessageBox().exec()

            if success == True:
                self.updateChordDict(self.window.mdiArea.currentSubWindow().doc)
                self.chordsw.widget().chordTableView.populate(self.window.mdiArea.currentSubWindow().doc.chordList)
                # update the names of chords in all blocklists in case they've already been used
                for s in self.window.mdiArea.currentSubWindow().doc.sectionList:
                    for b in s.blockList:
                        if b.chord:
                            if b.chord.name == oldName:
                                b.chord.name = cName
                if self.currentSection and self.currentSection.blockList:
                    self.blocksw.widget().blockTableView.populate(self.currentSection.blockList)
                self.clearChordLineEdits()

    def removeSectionAction(self):
        if self.sectionsw.widget().sectionTableView.selectionModel().hasSelection():  #  check for selection
            self.window.mdiArea.currentSubWindow().updateSections()

            row = self.sectionsw.widget().sectionTableView.selectionModel().currentIndex().row()
            self.window.mdiArea.currentSubWindow().doc.sectionList.pop(row)

            self.sectionsw.widget().sectionTableView.populate(self.window.mdiArea.currentSubWindow().doc.sectionList)
            self.clearSectionLineEdits()
            self.updateSectionDict(self.window.mdiArea.currentSubWindow().doc)

    def addSectionAction(self):
        self.window.mdiArea.currentSubWindow().updateSections()

        sName = self.sectionsw.widget().sectionNameLineEdit.text()
        if sName and sName not in [s.name for s in self.window.mdiArea.currentSubWindow().doc.sectionList]:
            self.window.mdiArea.currentSubWindow().doc.sectionList.append(Section(name=sName))
            self.sectionsw.widget().sectionTableView.populate(self.window.mdiArea.currentSubWindow().doc.sectionList)
            self.clearSectionLineEdits()
            self.updateSectionDict(self.window.mdiArea.currentSubWindow().doc)
        else:
            # Section has no name or non unique, warn user
            SectionNameWarningMessageBox().exec()

    def updateSectionAction(self):
        if self.sectionsw.widget().sectionTableView.selectionModel().hasSelection():  #  check for selection
            self.window.mdiArea.currentSubWindow().updateSections()
            row = self.sectionsw.widget().sectionTableView.selectionModel().currentIndex().row()

            sName = self.sectionsw.widget().sectionNameLineEdit.text()
            if sName and sName not in [s.name for s in self.window.mdiArea.currentSubWindow().doc.sectionList]:
                self.window.mdiArea.currentSubWindow().doc.sectionList[row].name = sName
                self.sectionsw.widget().sectionTableView.populate(self.window.mdiArea.currentSubWindow().doc.sectionList)
                self.clearSectionLineEdits()
                self.updateSectionDict(self.window.mdiArea.currentSubWindow().doc)
            else:
                # Section has no name or non unique, warn user
                SectionNameWarningMessageBox().exec()

    def removeBlockAction(self):
        if self.blocksw.widget().blockTableView.selectionModel().hasSelection():  #  check for selection
            self.window.mdiArea.currentSubWindow().updateBlocks(self.currentSection)

            row = self.blocksw.widget().blockTableView.selectionModel().currentIndex().row()
            self.currentSection.blockList.pop(row)

            self.blocksw.widget().blockTableView.populate(self.currentSection.blockList)

    def addBlockAction(self):
        self.window.mdiArea.currentSubWindow().updateBlocks(self.currentSection)

        try:
            #  can the value entered for block length be cast as a float
            bLength = float(self.blocksw.widget().blockLengthLineEdit.text())
        except Exception:
            bLength = False

        if bLength:  # create the block
            self.currentSection.blockList.append(Block(bLength,
                                                       chord=self.chordDict[self.blocksw.widget().blockChordComboBox.currentText(
                                                       )],
                                                       notes=(self.blocksw.widget().blockNotesLineEdit.text() if not "" else None)))
            self.blocksw.widget().blockTableView.populate(self.currentSection.blockList)
            self.clearBlockLineEdits()
        else:
            # show warning that length was not entered or in wrong format
            LengthWarningMessageBox().exec()

    def updateBlockAction(self):
        if self.blocksw.widget().blockTableView.selectionModel().hasSelection():  #  check for selection
            self.window.mdiArea.currentSubWindow().updateBlocks(self.currentSection)

            try:
                #  can the value entered for block length be cast as a float
                bLength = float(self.blocksw.widget().blockLengthLineEdit.text())
            except Exception:
                bLength = False

            row = self.blocksw.widget().blockTableView.selectionModel().currentIndex().row()
            if bLength:
                self.currentSection.blockList[row] = (Block(bLength,
                                                            chord=self.chordDict[self.blocksw.widget().blockChordComboBox.currentText(
                                                            )],
                                                            notes=(self.blocksw.widget().blockNotesLineEdit.text() if not "" else None)))
                self.blocksw.widget().blockTableView.populate(
                    self.currentSection.blockList)
                self.clearBlockLineEdits()
            else:
                LengthWarningMessageBox().exec()
        
    def pageSizeAction(self, index):
        self.pageSizeSelected = self.psetup.widget().pageSizeComboBox.itemText(index)

    def unitAction(self, index):
        self.unitSelected = self.psetup.widget().documentUnitsComboBox.itemText(index)

    def includedFontAction(self):
        if self.window.mdiArea.currentSubWindow() is not None:
            if self.psetup.widget().includedFontCheckBox.isChecked():
                self.window.mdiArea.currentSubWindow().style.useIncludedFont = True
            else:
                self.window.mdiArea.currentSubWindow().style.useIncludedFont = False
        
    def chordClickedAction(self, index):
        # set the controls to the values from the selected chord
        self.chordsw.widget().chordNameLineEdit.setText(
            self.chordsw.widget().chordTableView.model.item(index.row(), 0).text())
        self.chordsw.widget().guitarVoicingLineEdit.setText(
            self.chordsw.widget().chordTableView.model.item(index.row(), 1).text())
        self.chordsw.widget().pianoVoicingLineEdit.setText(
            self.chordsw.widget().chordTableView.model.item(index.row(), 2).text())

    def sectionClickedAction(self, index):
        # set the controls to the values from the selected section
        self.sectionsw.widget().sectionNameLineEdit.setText(
            self.sectionsw.widget().sectionTableView.model.item(index.row(), 0).text())
        # also set the combo box on the block page to make it flow well
        curSecName = self.sectionsw.widget().sectionTableView.model.item(
            index.row(), 0).text()
        if curSecName:
            self.blocksw.widget().blockSectionComboBox.setCurrentText(
                curSecName)

    def blockSectionClickedAction(self, text):
        if text:
            self.window.mdiArea.currentSubWindow().updateBlocks(self.sectionDict[text])

    def blockSectionChangedAction(self, index):
        sName = self.blocksw.widget().blockSectionComboBox.currentText()
        if sName:
            if self.window.mdiArea.currentSubWindow() is not None:
                self.currentSection = self.sectionDict.get(sName, None)
                # self.window.mdiArea.currentSubWindow().currentSection = self.currentSection
                if self.currentSection is not None:
                    self.blocksw.widget().blockTableView.populate(self.currentSection.blockList)
        else:
            pass # self.currentSection = None

    def blockClickedAction(self, index):
        # set the controls to the values from the selected block
        bChord = self.blocksw.widget().blockTableView.model.item(index.row(), 0).text()
        self.blocksw.widget().blockChordComboBox.setCurrentText(
            bChord if bChord else "None")
        self.blocksw.widget().blockLengthLineEdit.setText(
            self.blocksw.widget().blockTableView.model.item(index.row(), 1).text())
        self.blocksw.widget().blockNotesLineEdit.setText(
            self.blocksw.widget().blockTableView.model.item(index.row(), 2).text())

    def getPath(self, value):
        """
        Wrapper for Qt settings to return home directory if no setting exists.
        """
        return str((settings.value(value) if settings.value(value) else os.path.expanduser("~")))

    def setPath(self, value, fullpath):
        """
        Wrapper for Qt settings to set path to open/save from next time from current file location.
        """
        return settings.setValue(value, os.path.dirname(fullpath))

    def menuFileNewAction(self):
        dw = DocumentWindow(Document(), Style(), None)
        self.window.mdiArea.addSubWindow(dw)
        self.UIInitDocument(dw.doc)
        dw.show()
        

    def menuFileOpenAction(self):
        filePath = QFileDialog.getOpenFileName(self.window, 'Open file', self.getPath(
            "workingPath"), "Chordsheet Markup Language files (*.xml *.cml);;Chordsheet Macro files (*.cma)")[0]
        if filePath:
            dw = DocumentWindow.openFile(filePath)
            self.window.mdiArea.addSubWindow(dw)
            self.UIInitDocument(dw.doc)
            self.UIInitStyle(dw.style)
            # self.currentSection = None
            
            dw.show()

    def menuFileSaveAction(self):
        if self.window.mdiArea.currentSubWindow() is not None:
            self.window.mdiArea.currentSubWindow().updateDocument()

            if  self.window.mdiArea.currentSubWindow().currentFilePath:
                fileExt = os.path.splitext(self.window.mdiArea.currentSubWindow().currentFilePath)[1].lower()
                if fileExt != ".cma":
                    # Chordsheet Macro files can't be saved at this time
                    self.window.mdiArea.currentSubWindow().saveFile(self.window.mdiArea.currentSubWindow().currentFilePath)
            else:
                filePath = QFileDialog.getSaveFileName(self.window, 'Save file', self.getPath(
                    "workingPath"), "Chordsheet ML files (*.xml *.cml)")[0]
                if filePath:
                    self.window.mdiArea.currentSubWindow().saveFile(filePath)

    def menuFileSaveAsAction(self):
        if self.window.mdiArea.currentSubWindow() is not None:
            self.window.mdiArea.currentSubWindow().updateDocument()
            filePath = QFileDialog.getSaveFileName(self.window, 'Save file', self.getPath(
                "workingPath"), "Chordsheet ML files (*.xml *.cml)")[0]
            if filePath:
                self.window.mdiArea.currentSubWindow().saveFile(filePath)

    def menuFileSavePDFAction(self):
        if self.window.mdiArea.currentSubWindow() is not None:
            self.window.mdiArea.currentSubWindow().updateDocument()
            self.window.mdiArea.currentSubWindow().updatePreview()
            filePath = QFileDialog.getSaveFileName(self.window, 'Save file', self.getPath(
                "lastExportPath"), "PDF files (*.pdf)")[0]
            if filePath:
                self.window.mdiArea.currentSubWindow().renderer.savePDF(filePath)
                self.window.mdiArea.currentSubWindow().setPath("lastExportPath", filePath)

    def menuFilePrintAction(self):
        if sys.platform == "darwin":
            pass
        #    subprocess.call()
        else:
            pass

    @pyqtSlot()
    def menuFileCloseAction(self):
        self.saveWarning()

    def menuFileAboutAction(self):
        AboutDialog()

    def menuEditUndoAction(self):
        try:
            QApplication.focusWidget().undo()  # see if the built in widget supports it
        except Exception:
            pass  #  if not just fail silently

    def menuEditRedoAction(self):
        try:
            QApplication.focusWidget().redo()
        except Exception:
            pass

    def menuEditCutAction(self):
        try:
            QApplication.focusWidget().cut()
        except Exception:
            pass

    def menuEditCopyAction(self):
        try:
            QApplication.focusWidget().copy()
        except Exception:
            pass

    def menuEditPasteAction(self):
        try:
            QApplication.focusWidget().paste()
        except Exception:
            pass


        #      self.docinfo = DocInfoDockWidget()
        # self.psetup = PageSetupDockWidget()
        # self.chordsw = ChordsDockWidget()
        # self.sectionsw = SectionsDockWidget()
        # self.blocksw = BlocksDockWidget()
        # self.previeww = PreviewDockWidget()

    def menuWindowDocInfoAction(self):
        if self.window.actionDocument_information.isChecked():
            self.docinfo.show()
        else:
            self.docinfo.hide()

    def menuWindowPageSetupAction(self):
        if self.window.actionPage_setup.isChecked():
            self.psetup.show()
        else:
            self.psetup.hide()

    def menuWindowChordsAction(self):
        if self.window.actionChords.isChecked():
            self.chordsw.show()
        else:
            self.chordsw.hide()


    def menuWindowSectionsAction(self):
        if self.window.actionSections.isChecked():
            self.sectionsw.show()
        else:
            self.sectionsw.hide()


    def menuWindowBlocksAction(self):
        if self.window.actionBlocks.isChecked():
            self.blocksw.show()
        else:
            self.blocksw.hide()


    def menuWindowPreviewAction(self):
        if self.window.actionPreview.isChecked():
            self.previeww.show()
        else:
            self.previeww.hide()


    def guitarVoicingAction(self):
        gdialog = GuitarDialog()

        voicing = gdialog.getVoicing()
        if voicing:
            self.chordsw.widget().guitarVoicingLineEdit.setText(voicing)

    def clearChordLineEdits(self):
        self.chordsw.widget().chordNameLineEdit.clear()
        self.chordsw.widget().guitarVoicingLineEdit.clear()
        self.chordsw.widget().pianoVoicingLineEdit.clear()
        # necessary on Mojave with PyInstaller (or previous contents will be shown)
        self.chordsw.widget().chordNameLineEdit.repaint()
        self.chordsw.widget().guitarVoicingLineEdit.repaint()
        self.chordsw.widget().pianoVoicingLineEdit.repaint()

    def clearSectionLineEdits(self):
        self.sectionsw.widget().sectionNameLineEdit.clear()
        # necessary on Mojave with PyInstaller (or previous contents will be shown)
        self.sectionsw.widget().sectionNameLineEdit.repaint()

    def clearBlockLineEdits(self):
        self.blocksw.widget().blockLengthLineEdit.clear()
        self.blocksw.widget().blockNotesLineEdit.clear()
        # necessary on Mojave with PyInstaller (or previous contents will be shown)
        self.blocksw.widget().blockLengthLineEdit.repaint()
        self.blocksw.widget().blockNotesLineEdit.repaint()








class DocumentWindow(QMdiSubWindow):
    def __init__(self, doc, style, filename):
        super().__init__()
        
        self.UIFileLoader(str(os.path.join(scriptDir, 'ui', 'document.ui')))
        
        self.doc = doc
        self.style = style
        self.renderer = Renderer(self.doc, self.style)

        self.lastDoc = copy(self.doc)
        self.currentFilePath = filename
        
        self.currentSection = None
        
        mw.updateChordDict(self.doc)
        mw.updateSectionDict(self.doc)
        
    def UIFileLoader(self, ui_file):
        ui_file = QFile(ui_file)
        ui_file.open(QFile.ReadOnly)

        self.setWidget(uic.loadUi(ui_file))
        ui_file.close()

    @classmethod
    def openFile(cls, filePath):
        dw = cls(Document(), Style(), None)
        dw.loadFile(filePath)
        return dw
    
    def loadFile(self, filePath):
        """
        Opens a file from a file path and sets up the window accordingly.
        """
        self.currentFilePath = filePath
        
        fileExt = os.path.splitext(self.currentFilePath)[1].lower()
        
        if fileExt == ".cma":
            self.doc.loadCSMacro(self.currentFilePath)
        else: # if fileExt in [".xml", ".cml"]:
            self.doc.loadXML(self.currentFilePath)
            
        self.updatePreview()
            
        self.lastDoc = copy(self.doc)
        mw.setPath("workingPath", self.currentFilePath)
        
        mw.updateChordDict(self.doc)
        mw.updateSectionDict(self.doc)
        
        self.currentSection = (self.doc.sectionList[0] if self.doc.sectionList else None)
        
        self.updateTitleBar()
        
    def saveFile(self, filePath):
        """
        Saves a file to given file path and sets up environment.
        """
        self.currentFilePath = filePath
        
        fileExt = os.path.splitext(self.currentFilePath)[1].lower()
        
        if fileExt == ".cma":
            # At this stage we should never get here
            pass
        else: # if fileExt in [".xml", ".cml"]:
            self.doc.saveXML(self.currentFilePath)
            
        self.lastDoc = copy(self.doc)
        mw.setPath("workingPath", self.currentFilePath)
        self.updateTitleBar()  # as we may have a new filename
        
    def saveWarning(self):
        """
        Function to check if the document has unsaved data in it and offer to save it.
        """
        self.updateDocument()  # update the document to catch all changes

        if self.lastDoc == self.doc:
            return True
        else:
            wantToSave = UnsavedMessageBox().exec()

            if wantToSave == QMessageBox.Save:
                if not self.currentFilePath:
                    filePath = QFileDialog.getSaveFileName(self.window, 'Save file', str(
                        os.path.expanduser("~")), "Chordsheet ML files (*.xml *.cml)")
                    self.currentFilePath = filePath[0]
                self.doc.saveXML(self.currentFilePath)
                return True

            elif wantToSave == QMessageBox.Discard:
                return True
            
            else:
                return False

    def updatePreview(self):
        """
        Update the preview shown by rendering a new PDF and drawing it to the scroll area.
        """
        try:
            self.currentPreview = self.renderer.stream()
        except Exception:
            QMessageBox.warning(self, "Preview failed", "Could not update the preview.",
                                buttons=QMessageBox.Ok, defaultButton=QMessageBox.Ok)
                                
                                
        with open('preview.pdf', 'wb') as f:
            f.write(self.currentPreview.getbuffer())

        self.widget().pdfArea.update_pdf(self.currentPreview)

    def updateTitleBar(self):
        """
        Update the application's title bar to reflect the current document.
        """
        if self.currentFilePath:
            self.widget().setWindowTitle(os.path.basename(self.currentFilePath))
        else:
            self.widget().setWindowTitle("Unsaved")

    def updateChords(self):
        """
        Update the chord list by reading the table.
        """
        chordTableList = []
        for i in range(mw.chordsw.widget().chordTableView.model.rowCount()):
            chordTableList.append(
                Chord(parseName(mw.chordsw.widget().chordTableView.model.item(i, 0).text()))),
            if mw.chordsw.widget().chordTableView.model.item(i, 1).text():
                chordTableList[-1].voicings['guitar'] = parseFingering(
                    mw.chordsw.widget().chordTableView.model.item(i, 1).text(), 'guitar')
            if mw.chordsw.widget().chordTableView.model.item(i, 2).text():
                chordTableList[-1].voicings['piano'] = parseFingering(
                    mw.chordsw.widget().chordTableView.model.item(i, 2).text(), 'piano')

        self.doc.chordList = chordTableList

    def matchSection(self, nameToMatch):
        """
        Given the name of a section, this function checks if it is already present in the document. 
        If it is, it's returned. If not, a new section with the given name is returned.
        """
        section = None
        for s in self.doc.sectionList:
            if s.name == nameToMatch:
                section = s
                break
        if section is None:
            section = Section(name=nameToMatch)
        return section

    def updateSections(self):
        """
        Update the section list by reading the table
        """
        sectionTableList = []
        for i in range(mw.sectionsw.widget().sectionTableView.model.rowCount()):
            sectionTableList.append(self.matchSection(
                mw.sectionsw.widget().sectionTableView.model.item(i, 0).text()))

        self.doc.sectionList = sectionTableList

    def updateBlocks(self, section):
        """
        Update the block list by reading the table.
        """
        if section is None:
            BlockMustHaveSectionWarningMessageBox().exec()
        else:
            blockTableList = []
            for i in range(mw.blocksw.widget().blockTableView.model.rowCount()):
                blockLength = float(
                    mw.blocksw.widget().blockTableView.model.item(i, 1).text())
                blockChord = mw.chordDict[(mw.blocksw.widget().blockTableView.model.item(
                    i, 0).text() if mw.blocksw.widget().blockTableView.model.item(i, 0).text() else "None")]
                blockNotes = mw.blocksw.widget().blockTableView.model.item(i, 2).text(
                ) if mw.blocksw.widget().blockTableView.model.item(i, 2).text() else None
                blockTableList.append(
                    Block(blockLength, chord=blockChord, notes=blockNotes))

            section.blockList = blockTableList
    def updateDocument(self):
        """
        Update the Document object by reading values from the UI.
        """
        self.doc.title = mw.docinfo.widget().titleLineEdit.text(
        )  # Title can be empty string but not None
        self.doc.subtitle = (mw.docinfo.widget().subtitleLineEdit.text(
        ) if mw.docinfo.widget().subtitleLineEdit.text() else None)
        self.doc.composer = (mw.docinfo.widget().composerLineEdit.text(
        ) if mw.docinfo.widget().composerLineEdit.text() else None)
        self.doc.arranger = (mw.docinfo.widget().arrangerLineEdit.text(
        ) if mw.docinfo.widget().arrangerLineEdit.text() else None)
        self.doc.tempo = (mw.docinfo.widget().tempoLineEdit.text(
        ) if mw.docinfo.widget().tempoLineEdit.text() else None)
        self.doc.timeSignature = int(mw.docinfo.widget().timeSignatureSpinBox.value(
        )) if mw.docinfo.widget().timeSignatureSpinBox.value() else self.doc.timeSignature

        self.style.pageSize = pageSizeDict[mw.pageSizeSelected]
        self.style.unit = unitDict[mw.unitSelected]
        self.style.leftMargin = float(mw.psetup.widget().leftMarginLineEdit.text(
        )) if mw.psetup.widget().leftMarginLineEdit.text() else self.style.leftMargin
        self.style.rightMargin = float(mw.psetup.widget().rightMarginLineEdit.text(
        )) if mw.psetup.widget().rightMarginLineEdit.text() else self.style.rightMargin
        self.style.topMargin = float(mw.psetup.widget().topMarginLineEdit.text(
        )) if mw.psetup.widget().topMarginLineEdit.text() else self.style.topMargin
        self.style.bottomMargin = float(mw.psetup.widget().bottomMarginLineEdit.text(
        )) if mw.psetup.widget().bottomMarginLineEdit.text() else self.style.bottomMargin
        self.style.lineSpacing = float(mw.psetup.widget().lineSpacingDoubleSpinBox.value(
        )) if mw.psetup.widget().lineSpacingDoubleSpinBox.value() else self.style.lineSpacing

        # make sure the unit width isn't too wide to draw!
        if mw.psetup.widget().beatWidthLineEdit.text():
            if (self.style.pageSize[0] - 2 * self.style.leftMargin * mm) >= (float(mw.psetup.widget().beatWidthLineEdit.text()) * 2 * self.doc.timeSignature * mm):
                self.style.unitWidth = float(
                    mw.psetup.widget().beatWidthLineEdit.text())
            else:
                maxBeatWidth = (
                    self.style.pageSize[0] - 2 * self.style.leftMargin * mm) / (2 * self.doc.timeSignature * mm)
                QMessageBox.warning(self, "Out of range", "Beat width is out of range. It can be a maximum of {}.".format(
                    maxBeatWidth), buttons=QMessageBox.Ok, defaultButton=QMessageBox.Ok)

        # update chords, sections, blocks
        self.updateChords()
        self.updateSections()
        if mw.currentSection:
            self.updateBlocks(mw.currentSection)

        self.style.font = (
            'FreeSans' if self.style.useIncludedFont else 'HelveticaNeue')
        # something for the font box here

if __name__ == '__main__':
    app = QApplication(sys.argv)

    # pass first argument as filename
    mw = MainWindow()
    mw.show()

    sys.exit(app.exec_())