#!/usr/bin/env python
 
 
#############################################################################
##
## Copyright (C) 2013 Riverbank Computing Limited.
## Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
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## This file is part of the examples of PyQt.
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##     the documentation and/or other materials provided with the
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#############################################################################
 
 
from PyQt5.QtCore import QAbstractItemModel, QFile, QIODevice, QModelIndex, Qt
from PyQt5.QtWidgets import QApplication, QTreeView
 
import simpletreemodel_rc
 
 
class TreeItem(object):
    def __init__(self, data, parent=None):
        self.parentItem = parent
        self.itemData = data
        self.childItems = []
 
    def appendChild(self, item):
        self.childItems.append(item)
 
    def child(self, row):
        return self.childItems[row]
 
    def childCount(self):
        return len(self.childItems)
 
    def columnCount(self):
        return len(self.itemData)
 
    def data(self, column):
        try:
            return self.itemData[column]
        except IndexError:
            return None
 
    def parent(self):
        return self.parentItem
 
    def row(self):
        if self.parentItem:
            return self.parentItem.childItems.index(self)
 
        return 0
 
 
class TreeModel(QAbstractItemModel):
    def __init__(self, data, parent=None):
        super(TreeModel, self).__init__(parent)
 
        self.rootItem = TreeItem(("Title", "Summary"))
        self.setupModelData(data.split('\n'), self.rootItem)
 
    def columnCount(self, parent):
        if parent.isValid():
            return parent.internalPointer().columnCount()
        else:
            return self.rootItem.columnCount()
 
    def data(self, index, role):
        if not index.isValid():
            return None
 
        if role != Qt.DisplayRole:
            return None
 
        item = index.internalPointer()
 
        return item.data(index.column())
 
    def flags(self, index):
        if not index.isValid():
            return Qt.NoItemFlags
 
        return Qt.ItemIsEnabled | Qt.ItemIsSelectable
 
    def headerData(self, section, orientation, role):
        if orientation == Qt.Horizontal and role == Qt.DisplayRole:
            return self.rootItem.data(section)
 
        return None
 
    def index(self, row, column, parent):
        if not self.hasIndex(row, column, parent):
            return QModelIndex()
 
        if not parent.isValid():
            parentItem = self.rootItem
        else:
            parentItem = parent.internalPointer()
 
        childItem = parentItem.child(row)
        if childItem:
            return self.createIndex(row, column, childItem)
        else:
            return QModelIndex()
 
    def parent(self, index):
        if not index.isValid():
            return QModelIndex()
 
        childItem = index.internalPointer()
        parentItem = childItem.parent()
 
        if parentItem == self.rootItem:
            return QModelIndex()
 
        return self.createIndex(parentItem.row(), 0, parentItem)
 
    def rowCount(self, parent):
        if parent.column() > 0:
            return 0
 
        if not parent.isValid():
            parentItem = self.rootItem
        else:
            parentItem = parent.internalPointer()
 
        return parentItem.childCount()
 
    def setupModelData(self, lines, parent):
        parents = [parent]
        indentations = [0]
 
        number = 0
 
        while number < len(lines):
            position = 0
            while position < len(lines[number]):
                if lines[number][position] != ' ':
                    break
                position += 1
 
            lineData = lines[number][position:].trimmed()
 
            if lineData:
                # Read the column data from the rest of the line.
                columnData = [s for s in lineData.split('\t') if s]
 
                if position > indentations[-1]:
                    # The last child of the current parent is now the new
                    # parent unless the current parent has no children.
 
                    if parents[-1].childCount() > 0:
                        parents.append(parents[-1].child(parents[-1].childCount() - 1))
                        indentations.append(position)
 
                else:
                    while position < indentations[-1] and len(parents) > 0:
                        parents.pop()
                        indentations.pop()
 
                # Append a new item to the current parent's list of children.
                parents[-1].appendChild(TreeItem(columnData, parents[-1]))
 
            number += 1
 
 
if __name__ == '__main__':
 
    import sys
 
    app = QApplication(sys.argv)
 
    f = QFile(':/default.txt')
    f.open(QIODevice.ReadOnly)
    model = TreeModel(f.readAll())
    f.close()
 
    view = QTreeView()
    view.setModel(model)
    view.setWindowTitle("Simple Tree Model")
    view.show()
    sys.exit(app.exec_())