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

# Copyright (c) 2007 - 2019 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing a typing completer for Python.
"""


import re

from PyQt5.QtCore import QRegExp
from PyQt5.Qsci import QsciLexerPython, QsciScintilla

from .CompleterBase import CompleterBase

import Preferences


class CompleterPython(CompleterBase):
    """
    Class implementing typing completer for Python.
    """
    def __init__(self, editor, parent=None):
        """
        Constructor
        
        @param editor reference to the editor object (QScintilla.Editor)
        @param parent reference to the parent object (QObject)
        """
        super(CompleterPython, self).__init__(editor, parent)
        
        self.__defRX = QRegExp(r"""^[ \t]*def \w+\(""")
        self.__defSelfRX = QRegExp(r"""^[ \t]*def \w+\([ \t]*self[ \t]*[,)]""")
        self.__defClsRX = QRegExp(r"""^[ \t]*def \w+\([ \t]*cls[ \t]*[,)]""")
        self.__classRX = QRegExp(r"""^[ \t]*class \w+\(""")
        self.__importRX = QRegExp(r"""^[ \t]*from [\w.]+ """)
        self.__classmethodRX = QRegExp(r"""^[ \t]*@classmethod""")
        self.__staticmethodRX = QRegExp(r"""^[ \t]*@staticmethod""")
        
        self.__defOnlyRX = QRegExp(r"""^[ \t]*def """)
        
        self.__ifRX = QRegExp(r"""^[ \t]*if """)
        self.__elifRX = QRegExp(r"""^[ \t]*elif """)
        self.__elseRX = QRegExp(r"""^[ \t]*else:""")
        
        self.__tryRX = QRegExp(r"""^[ \t]*try:""")
        self.__finallyRX = QRegExp(r"""^[ \t]*finally:""")
        self.__exceptRX = QRegExp(r"""^[ \t]*except """)
        self.__exceptcRX = QRegExp(r"""^[ \t]*except:""")
        
        self.__whileRX = QRegExp(r"""^[ \t]*while """)
        self.__forRX = QRegExp(r"""^[ \t]*for """)
        
        self.readSettings()
    
    def readSettings(self):
        """
        Public slot called to reread the configuration parameters.
        """
        self.setEnabled(
            Preferences.getEditorTyping("Python/EnabledTypingAids"))
        self.__insertClosingBrace = Preferences.getEditorTyping(
            "Python/InsertClosingBrace")
        self.__indentBrace = Preferences.getEditorTyping(
            "Python/IndentBrace")
        self.__skipBrace = Preferences.getEditorTyping(
            "Python/SkipBrace")
        self.__insertQuote = Preferences.getEditorTyping(
            "Python/InsertQuote")
        self.__dedentElse = Preferences.getEditorTyping(
            "Python/DedentElse")
        self.__dedentExcept = Preferences.getEditorTyping(
            "Python/DedentExcept")
        self.__insertImport = Preferences.getEditorTyping(
            "Python/InsertImport")
        self.__importBraceType = Preferences.getEditorTyping(
            "Python/ImportBraceType")
        self.__insertSelf = Preferences.getEditorTyping(
            "Python/InsertSelf")
        self.__insertBlank = Preferences.getEditorTyping(
            "Python/InsertBlank")
        self.__colonDetection = Preferences.getEditorTyping(
            "Python/ColonDetection")
        self.__dedentDef = Preferences.getEditorTyping(
            "Python/DedentDef")

    def charAdded(self, charNumber):
        """
        Public slot called to handle the user entering a character.
        
        @param charNumber value of the character entered (integer)
        """
        char = chr(charNumber)
        if char not in ['(', ')', '{', '}', '[', ']', ' ', ',', "'", '"',
                        '\n', ':']:
            return  # take the short route
        
        line, col = self.editor.getCursorPosition()
        
        if (
            self.__inComment(line, col) or
            (char != '"' and self.__inDoubleQuotedString()) or
            (char != '"' and self.__inTripleDoubleQuotedString()) or
            (char != "'" and self.__inSingleQuotedString()) or
            (char != "'" and self.__inTripleSingleQuotedString())
        ):
            return
        
        # open parenthesis
        # insert closing parenthesis and self
        if char == '(':
            txt = self.editor.text(line)[:col]
            if (
                self.__insertSelf and
                self.__defRX.exactMatch(txt)
            ):
                if self.__isClassMethodDef():
                    self.editor.insert('cls')
                    self.editor.setCursorPosition(line, col + 3)
                elif self.__isStaticMethodDef():
                    # nothing to insert
                    pass
                elif self.__isClassMethod():
                    self.editor.insert('self')
                    self.editor.setCursorPosition(line, col + 4)
            if self.__insertClosingBrace:
                if (
                    self.__defRX.exactMatch(txt) or
                    self.__classRX.exactMatch(txt)
                ):
                    self.editor.insert('):')
                else:
                    self.editor.insert(')')
        
        # closing parenthesis
        # skip matching closing parenthesis
        elif char in [')', '}', ']']:
            txt = self.editor.text(line)
            if col < len(txt) and char == txt[col]:
                if self.__skipBrace:
                    self.editor.setSelection(line, col, line, col + 1)
                    self.editor.removeSelectedText()
        
        # space
        # insert import, dedent to if for elif, dedent to try for except,
        # dedent def
        elif char == ' ':
            txt = self.editor.text(line)[:col]
            if self.__insertImport and self.__importRX.exactMatch(txt):
                if self.__importBraceType:
                    self.editor.insert('import ()')
                    self.editor.setCursorPosition(line, col + 8)
                else:
                    self.editor.insert('import ')
                    self.editor.setCursorPosition(line, col + 7)
            elif self.__dedentElse and self.__elifRX.exactMatch(txt):
                self.__dedentToIf()
            elif self.__dedentExcept and self.__exceptRX.exactMatch(txt):
                self.__dedentExceptToTry(False)
            elif self.__dedentDef and self.__defOnlyRX.exactMatch(txt):
                self.__dedentDefStatement()
        
        # comma
        # insert blank
        elif char == ',':
            if self.__insertBlank:
                self.editor.insert(' ')
                self.editor.setCursorPosition(line, col + 1)
        
        # open curly brace
        # insert closing brace
        elif char == '{':
            if self.__insertClosingBrace:
                self.editor.insert('}')
        
        # open bracket
        # insert closing bracket
        elif char == '[':
            if self.__insertClosingBrace:
                self.editor.insert(']')
        
        # double quote
        # insert double quote
        elif char == '"':
            if self.__insertQuote:
                self.editor.insert('"')
        
        # quote
        # insert quote
        elif char == '\'':
            if self.__insertQuote:
                self.editor.insert('\'')
        
        # colon
        # skip colon, dedent to if for else:
        elif char == ':':
            text = self.editor.text(line)
            if col < len(text) and char == text[col]:
                if self.__colonDetection:
                    self.editor.setSelection(line, col, line, col + 1)
                    self.editor.removeSelectedText()
            else:
                txt = text[:col]
                if self.__dedentElse and self.__elseRX.exactMatch(txt):
                    self.__dedentElseToIfWhileForTry()
                elif self.__dedentExcept and self.__exceptcRX.exactMatch(txt):
                    self.__dedentExceptToTry(True)
                elif self.__dedentExcept and self.__finallyRX.exactMatch(txt):
                    self.__dedentFinallyToTry()
        
        # new line
        # indent to opening brace
        elif char == '\n':
            if self.__indentBrace:
                txt = self.editor.text(line - 1)
                if re.search(":\r?\n", txt) is None:
                    stxt = txt.strip()
                    if stxt and stxt[-1] in ("(", "[", "{"):
                        # indent one more level
                        self.editor.indent(line)
                        self.editor.editorCommand(QsciScintilla.SCI_VCHOME)
                    else:
                        # indent to the level of the opening brace
                        openCount = len(re.findall("[({[]", txt))
                        closeCount = len(re.findall(r"[)}\]]", txt))
                        if openCount > closeCount:
                            openCount = 0
                            closeCount = 0
                            openList = list(re.finditer("[({[]", txt))
                            index = len(openList) - 1
                            while index > -1 and openCount == closeCount:
                                lastOpenIndex = openList[index].start()
                                txt2 = txt[lastOpenIndex:]
                                openCount = len(re.findall("[({[]", txt2))
                                closeCount = len(re.findall(r"[)}\]]", txt2))
                                index -= 1
                            if openCount > closeCount and lastOpenIndex > col:
                                self.editor.insert(
                                    ' ' * (lastOpenIndex - col + 1))
                                self.editor.setCursorPosition(
                                    line, lastOpenIndex + 1)
    
    def __dedentToIf(self):
        """
        Private method to dedent the last line to the last if statement with
        less (or equal) indentation.
        """
        line, col = self.editor.getCursorPosition()
        indentation = self.editor.indentation(line)
        ifLine = line - 1
        while ifLine >= 0:
            txt = self.editor.text(ifLine)
            edInd = self.editor.indentation(ifLine)
            if self.__elseRX.indexIn(txt) == 0 and edInd <= indentation:
                indentation = edInd - 1
            elif (self.__ifRX.indexIn(txt) == 0 or
                  self.__elifRX.indexIn(txt) == 0) and edInd <= indentation:
                self.editor.cancelList()
                self.editor.setIndentation(line, edInd)
                break
            ifLine -= 1
    
    def __dedentElseToIfWhileForTry(self):
        """
        Private method to dedent the line of the else statement to the last
        if, while, for or try statement with less (or equal) indentation.
        """
        line, col = self.editor.getCursorPosition()
        indentation = self.editor.indentation(line)
        if line > 0:
            prevInd = self.editor.indentation(line - 1)
        ifLine = line - 1
        while ifLine >= 0:
            txt = self.editor.text(ifLine)
            edInd = self.editor.indentation(ifLine)
            if self.__elseRX.indexIn(txt) == 0 and edInd <= indentation:
                indentation = edInd - 1
            elif (
                self.__elifRX.indexIn(txt) == 0 and
                edInd == indentation and
                edInd == prevInd
            ):
                indentation = edInd - 1
            elif (
                (self.__ifRX.indexIn(txt) == 0 or
                 self.__whileRX.indexIn(txt) == 0 or
                 self.__forRX.indexIn(txt) == 0 or
                 self.__tryRX.indexIn(txt) == 0) and
                edInd <= indentation
            ):
                self.editor.cancelList()
                self.editor.setIndentation(line, edInd)
                break
            ifLine -= 1
    
    def __dedentExceptToTry(self, hasColon):
        """
        Private method to dedent the line of the except statement to the last
        try statement with less (or equal) indentation.
        
        @param hasColon flag indicating the except type (boolean)
        """
        line, col = self.editor.getCursorPosition()
        indentation = self.editor.indentation(line)
        tryLine = line - 1
        while tryLine >= 0:
            txt = self.editor.text(tryLine)
            edInd = self.editor.indentation(tryLine)
            if (
                (self.__exceptcRX.indexIn(txt) == 0 or
                 self.__finallyRX.indexIn(txt) == 0) and
                edInd <= indentation
            ):
                indentation = edInd - 1
            elif (self.__exceptRX.indexIn(txt) == 0 or
                  self.__tryRX.indexIn(txt) == 0) and edInd <= indentation:
                self.editor.cancelList()
                self.editor.setIndentation(line, edInd)
                break
            tryLine -= 1
    
    def __dedentFinallyToTry(self):
        """
        Private method to dedent the line of the except statement to the last
        try statement with less (or equal) indentation.
        """
        line, col = self.editor.getCursorPosition()
        indentation = self.editor.indentation(line)
        tryLine = line - 1
        while tryLine >= 0:
            txt = self.editor.text(tryLine)
            edInd = self.editor.indentation(tryLine)
            if self.__finallyRX.indexIn(txt) == 0 and edInd <= indentation:
                indentation = edInd - 1
            elif (
                (self.__tryRX.indexIn(txt) == 0 or
                 self.__exceptcRX.indexIn(txt) == 0 or
                 self.__exceptRX.indexIn(txt) == 0) and
                edInd <= indentation
            ):
                self.editor.cancelList()
                self.editor.setIndentation(line, edInd)
                break
            tryLine -= 1
    
    def __dedentDefStatement(self):
        """
        Private method to dedent the line of the def statement to a previous
        def statement or class statement.
        """
        line, col = self.editor.getCursorPosition()
        indentation = self.editor.indentation(line)
        tryLine = line - 1
        while tryLine >= 0:
            txt = self.editor.text(tryLine)
            edInd = self.editor.indentation(tryLine)
            newInd = -1
            if self.__defRX.indexIn(txt) == 0 and edInd < indentation:
                newInd = edInd
            elif self.__classRX.indexIn(txt) == 0 and edInd < indentation:
                newInd = edInd + (
                    self.editor.indentationWidth() or self.editor.tabWidth()
                )
            if newInd >= 0:
                self.editor.cancelList()
                self.editor.setIndentation(line, newInd)
                break
            tryLine -= 1
    
    def __isClassMethod(self):
        """
        Private method to check, if the user is defining a class method.
        
        @return flag indicating the definition of a class method (boolean)
        """
        line, col = self.editor.getCursorPosition()
        indentation = self.editor.indentation(line)
        curLine = line - 1
        while curLine >= 0:
            txt = self.editor.text(curLine)
            if (
                (self.__defSelfRX.indexIn(txt) == 0 or
                 self.__defClsRX.indexIn(txt) == 0) and
                self.editor.indentation(curLine) == indentation
            ):
                return True
            elif (
                self.__classRX.indexIn(txt) == 0 and
                self.editor.indentation(curLine) < indentation
            ):
                return True
            elif (
                self.__defRX.indexIn(txt) == 0 and
                self.editor.indentation(curLine) <= indentation
            ):
                return False
            curLine -= 1
        return False
    
    def __isClassMethodDef(self):
        """
        Private method to check, if the user is defing a class method
        (@classmethod).
        
        @return flag indicating the definition of a class method (boolean)
        """
        line, col = self.editor.getCursorPosition()
        indentation = self.editor.indentation(line)
        curLine = line - 1
        if (
            self.__classmethodRX.indexIn(self.editor.text(curLine)) == 0 and
            self.editor.indentation(curLine) == indentation
        ):
            return True
        return False
    
    def __isStaticMethodDef(self):
        """
        Private method to check, if the user is defing a static method
        (@staticmethod) method.
        
        @return flag indicating the definition of a static method (boolean)
        """
        line, col = self.editor.getCursorPosition()
        indentation = self.editor.indentation(line)
        curLine = line - 1
        if (
            self.__staticmethodRX.indexIn(self.editor.text(curLine)) == 0 and
            self.editor.indentation(curLine) == indentation
        ):
            return True
        return False
    
    def __inComment(self, line, col):
        """
        Private method to check, if the cursor is inside a comment.
        
        @param line current line (integer)
        @param col current position within line (integer)
        @return flag indicating, if the cursor is inside a comment (boolean)
        """
        txt = self.editor.text(line)
        if col == len(txt):
            col -= 1
        while col >= 0:
            if txt[col] == "#":
                return True
            col -= 1
        return False
    
    def __inDoubleQuotedString(self):
        """
        Private method to check, if the cursor is within a double quoted
        string.
        
        @return flag indicating, if the cursor is inside a double
            quoted string (boolean)
        """
        return self.editor.currentStyle() == QsciLexerPython.DoubleQuotedString
    
    def __inTripleDoubleQuotedString(self):
        """
        Private method to check, if the cursor is within a triple double
        quoted string.
        
        @return flag indicating, if the cursor is inside a triple double
            quoted string (boolean)
        """
        return (
            self.editor.currentStyle() ==
            QsciLexerPython.TripleDoubleQuotedString
        )
    
    def __inSingleQuotedString(self):
        """
        Private method to check, if the cursor is within a single quoted
        string.
        
        @return flag indicating, if the cursor is inside a single
            quoted string (boolean)
        """
        return self.editor.currentStyle() == QsciLexerPython.SingleQuotedString
    
    def __inTripleSingleQuotedString(self):
        """
        Private method to check, if the cursor is within a triple single
        quoted string.
        
        @return flag indicating, if the cursor is inside a triple single
            quoted string (boolean)
        """
        return (
            self.editor.currentStyle() ==
            QsciLexerPython.TripleSingleQuotedString
        )
