############################################################
# FlatCAM: 2D Post-processing for Manufacturing            #
# http://flatcam.org                                       #
# Author: Juan Pablo Caram (c)                             #
# Date: 2/5/2014                                           #
# MIT Licence                                              #
############################################################

import html
from PyQt5.QtCore import pyqtSignal
from PyQt5.QtCore import Qt, QStringListModel
from PyQt5.QtGui import QColor, QKeySequence, QPalette, QTextCursor
from PyQt5.QtWidgets import QLineEdit, QSizePolicy, QTextEdit, QVBoxLayout, QWidget, QCompleter, QAction

class _BrowserTextEdit(QTextEdit):

    def __init__(self, version):
        QTextEdit.__init__(self)
        self.menu = None
        self.version = version

    def contextMenuEvent(self, event):
        self.menu = self.createStandardContextMenu(event.pos())
        clear_action = QAction("Clear", self)
        clear_action.setShortcut(QKeySequence(Qt.Key_Delete))   # it's not working, the shortcut
        self.menu.addAction(clear_action)
        clear_action.triggered.connect(self.clear)
        self.menu.exec_(event.globalPos())


    def clear(self):
        QTextEdit.clear(self)
        text = "FlatCAM %s (c)2014-2019 Juan Pablo Caram (Type help to get started)\n\n" % self.version
        text = html.escape(text)
        text = text.replace('\n', '<br/>')
        self.moveCursor(QTextCursor.End)
        self.insertHtml(text)

class _ExpandableTextEdit(QTextEdit):
    """
    Class implements edit line, which expands themselves automatically
    """

    historyNext = pyqtSignal()
    historyPrev = pyqtSignal()

    def __init__(self, termwidget, *args):
        QTextEdit.__init__(self, *args)
        self.setStyleSheet("font: 9pt \"Courier\";")
        self._fittedHeight = 1
        self.textChanged.connect(self._fit_to_document)
        self._fit_to_document()
        self._termWidget = termwidget

        self.completer = MyCompleter()

        self.model = QStringListModel()
        self.completer.setModel(self.model)
        self.set_model_data(keyword_list=[])
        self.completer.insertText.connect(self.insertCompletion)

    def set_model_data(self, keyword_list):
        self.model.setStringList(keyword_list)

    def insertCompletion(self, completion):
        tc = self.textCursor()
        extra = (len(completion) - len(self.completer.completionPrefix()))
        tc.movePosition(QTextCursor.Left)
        tc.movePosition(QTextCursor.EndOfWord)
        tc.insertText(completion[-extra:])
        self.setTextCursor(tc)
        self.completer.popup().hide()

    def focusInEvent(self, event):
        if self.completer:
            self.completer.setWidget(self)
        QTextEdit.focusInEvent(self, event)

    def keyPressEvent(self, event):
        """
        Catch keyboard events. Process Enter, Up, Down
        """
        if event.matches(QKeySequence.InsertParagraphSeparator):
            text = self.toPlainText()
            if self._termWidget.is_command_complete(text):
                self._termWidget.exec_current_command()
                return
        elif event.matches(QKeySequence.MoveToNextLine):
            text = self.toPlainText()
            cursor_pos = self.textCursor().position()
            textBeforeEnd = text[cursor_pos:]

            if len(textBeforeEnd.split('\n')) <= 1:
                self.historyNext.emit()
                return
        elif event.matches(QKeySequence.MoveToPreviousLine):
            text = self.toPlainText()
            cursor_pos = self.textCursor().position()
            text_before_start = text[:cursor_pos]
            # lineCount = len(textBeforeStart.splitlines())
            line_count = len(text_before_start.split('\n'))
            if len(text_before_start) > 0 and \
                    (text_before_start[-1] == '\n' or text_before_start[-1] == '\r'):
                line_count += 1
            if line_count <= 1:
                self.historyPrev.emit()
                return
        elif event.matches(QKeySequence.MoveToNextPage) or \
                event.matches(QKeySequence.MoveToPreviousPage):
            return self._termWidget.browser().keyPressEvent(event)

        tc = self.textCursor()
        if event.key() == Qt.Key_Tab and self.completer.popup().isVisible():
            self.completer.insertText.emit(self.completer.getSelected())
            self.completer.setCompletionMode(QCompleter.PopupCompletion)
            return

        QTextEdit.keyPressEvent(self, event)
        tc.select(QTextCursor.WordUnderCursor)
        cr = self.cursorRect()

        if len(tc.selectedText()) > 0:
            self.completer.setCompletionPrefix(tc.selectedText())
            popup = self.completer.popup()
            popup.setCurrentIndex(self.completer.completionModel().index(0, 0))

            cr.setWidth(self.completer.popup().sizeHintForColumn(0)
                        + self.completer.popup().verticalScrollBar().sizeHint().width())
            self.completer.complete(cr)
        else:
            self.completer.popup().hide()

    def sizeHint(self):
        """
        QWidget sizeHint impelemtation
        """
        hint = QTextEdit.sizeHint(self)
        hint.setHeight(self._fittedHeight)
        return hint

    def _fit_to_document(self):
        """
        Update widget height to fit all text
        """
        documentsize = self.document().size().toSize()
        self._fittedHeight = documentsize.height() + (self.height() - self.viewport().height())
        self.setMaximumHeight(self._fittedHeight)
        self.updateGeometry()

    def insertFromMimeData(self, mime_data):
        # Paste only plain text.
        self.insertPlainText(mime_data.text())


class MyCompleter(QCompleter):
    insertText = pyqtSignal(str)

    def __init__(self, parent=None):
        QCompleter.__init__(self)
        self.setCompletionMode(QCompleter.PopupCompletion)
        self.highlighted.connect(self.setHighlighted)

    def setHighlighted(self, text):
        self.lastSelected = text

    def getSelected(self):
        return self.lastSelected


class TermWidget(QWidget):
    """
    Widget wich represents terminal. It only displays text and allows to enter text.
    All highlevel logic should be implemented by client classes

    User pressed Enter. Client class should decide, if command must be executed or user may continue edit it
    """

    def __init__(self, version, *args):
        QWidget.__init__(self, *args)

        self._browser = _BrowserTextEdit(version=version)
        self._browser.setStyleSheet("font: 9pt \"Courier\";")
        self._browser.setReadOnly(True)
        self._browser.document().setDefaultStyleSheet(
            self._browser.document().defaultStyleSheet() +
            "span {white-space:pre;}")

        self._edit = _ExpandableTextEdit(self, self)
        self._edit.historyNext.connect(self._on_history_next)
        self._edit.historyPrev.connect(self._on_history_prev)
        self._edit.setFocus()
        self.setFocusProxy(self._edit)

        layout = QVBoxLayout(self)
        layout.setSpacing(0)
        layout.setContentsMargins(0, 0, 0, 0)
        layout.addWidget(self._browser)
        layout.addWidget(self._edit)

        self._history = ['']  # current empty line
        self._historyIndex = 0

    def open_proccessing(self, detail=None):
        """
        Open processing and disable using shell commands  again until all commands are finished

        :param detail: text detail about what is currently called from TCL to python
        :return: None
        """

        self._edit.setTextColor(Qt.white)
        self._edit.setTextBackgroundColor(Qt.darkGreen)
        if detail is None:
            self._edit.setPlainText("...proccessing...")
        else:
            self._edit.setPlainText("...proccessing... [%s]" % detail)

        self._edit.setDisabled(True)
        self._edit.setFocus()

    def close_proccessing(self):
        """
        Close processing and enable using shell commands  again
        :return:
        """

        self._edit.setTextColor(Qt.black)
        self._edit.setTextBackgroundColor(Qt.white)
        self._edit.setPlainText('')
        self._edit.setDisabled(False)
        self._edit.setFocus()

    def _append_to_browser(self, style, text):
        """
        Convert text to HTML for inserting it to browser
        """
        assert style in ('in', 'out', 'err', 'warning', 'success')

        text = html.escape(text)
        text = text.replace('\n', '<br/>')

        if style == 'in':
            text = '<span style="font-weight: bold;">%s</span>' % text
        elif style == 'err':
            text = '<span style="font-weight: bold; color: red;">%s</span>' % text
        elif style == 'warning':
            text = '<span style="font-weight: bold; color: rgb(244, 182, 66);">%s</span>' % text
        elif style == 'success':
            text = '<span style="font-weight: bold; color: rgb(8, 68, 0);">%s</span>' % text
        else:
            text = '<span>%s</span>' % text  # without span <br/> is ignored!!!

        scrollbar = self._browser.verticalScrollBar()
        old_value = scrollbar.value()
        scrollattheend = old_value == scrollbar.maximum()

        self._browser.moveCursor(QTextCursor.End)
        self._browser.insertHtml(text)

        """TODO When user enters second line to the input, and input is resized, scrollbar changes its positon
        and stops moving. As quick fix of this problem, now we always scroll down when add new text.
        To fix it correctly, srcoll to the bottom, if before intput has been resized,
        scrollbar was in the bottom, and remove next lien
        """
        scrollattheend = True

        if scrollattheend:
            scrollbar.setValue(scrollbar.maximum())
        else:
            scrollbar.setValue(old_value)

    def exec_current_command(self):
        """
        Save current command in the history. Append it to the log. Clear edit line
        Reimplement in the child classes to actually execute command
        """
        text = str(self._edit.toPlainText())
        self._append_to_browser('in', '> ' + text + '\n')

        if len(self._history) < 2 or\
           self._history[-2] != text:  # don't insert duplicating items
            if text[-1] == '\n':
                self._history.insert(-1, text[:-1])
            else:
                self._history.insert(-1, text)

        self._historyIndex = len(self._history) - 1

        self._history[-1] = ''
        self._edit.clear()

        if not text[-1] == '\n':
            text += '\n'

        self.child_exec_command(text)

    def child_exec_command(self, text):
        """
        Reimplement in the child classes
        """
        pass

    def add_line_break_to_input(self):
        self._edit.textCursor().insertText('\n')

    def append_output(self, text):
        """Appent text to output widget
        """
        self._append_to_browser('out', text)

    def append_success(self, text):
        """Appent text to output widget
        """
        self._append_to_browser('success', text)

    def append_warning(self, text):
        """Appent text to output widget
        """
        self._append_to_browser('warning', text)

    def append_error(self, text):
        """Appent error text to output widget. Text is drawn with red background
        """
        self._append_to_browser('err', text)

    def is_command_complete(self, text):
        """
        Executed by _ExpandableTextEdit. Reimplement this function in the child classes.
        """
        return True

    def browser(self):
        return self._browser

    def _on_history_next(self):
        """
        Down pressed, show next item from the history
        """
        if (self._historyIndex + 1) < len(self._history):
            self._historyIndex += 1
            self._edit.setPlainText(self._history[self._historyIndex])
            self._edit.moveCursor(QTextCursor.End)

    def _on_history_prev(self):
        """
        Up pressed, show previous item from the history
        """
        if self._historyIndex > 0:
            if self._historyIndex == (len(self._history) - 1):
                self._history[-1] = self._edit.toPlainText()
            self._historyIndex -= 1
            self._edit.setPlainText(self._history[self._historyIndex])
            self._edit.moveCursor(QTextCursor.End)

class FCShell(TermWidget):
    def __init__(self, sysShell, version, *args):
        TermWidget.__init__(self, version, *args)
        self._sysShell = sysShell

    def is_command_complete(self, text):
        def skipQuotes(text):
            quote = text[0]
            text = text[1:]
            endIndex = str(text).index(quote)
            return text[endIndex:]
        while text:
            if text[0] in ('"', "'"):
                try:
                    text = skipQuotes(text)
                except ValueError:
                    return False
            text = text[1:]
        return True

    def child_exec_command(self, text):
        self._sysShell.exec_command(text)