import re

from PyQt5 import QtCore, QtGui, QtWidgets, Qsci
from chordpro.constants import KNOWN_DIRECTIVES, KNOWN_VERSE_TYPES

PALETTE_ROLES = {
    'window': QtGui.QPalette.WindowText,
    'background': QtGui.QPalette.Background,
    'windowtext': QtGui.QPalette.WindowText,
    'foreground': QtGui.QPalette.Foreground,
    'base': QtGui.QPalette.Base,
    'alternatebase': QtGui.QPalette.AlternateBase,
    'tooltipbase': QtGui.QPalette.ToolTipBase,
    'tooltiptext': QtGui.QPalette.ToolTipText,
    'placeholderText': QtGui.QPalette.PlaceholderText,
    'text': QtGui.QPalette.Text,
    'button': QtGui.QPalette.Button,
    'buttontext': QtGui.QPalette.ButtonText,
    'brighttext': QtGui.QPalette.BrightText,
    'light': QtGui.QPalette.Light,
    'midlight': QtGui.QPalette.Midlight,
    'dark': QtGui.QPalette.Dark,
    'mid': QtGui.QPalette.Mid,
    'shadow': QtGui.QPalette.Shadow,
    'highlight': QtGui.QPalette.Highlight,
    'highlightedtext': QtGui.QPalette.HighlightedText,
    'link': QtGui.QPalette.Link,
    'linkvisited': QtGui.QPalette.LinkVisited
}


class ChordProStyle(object):
    Default = 0
    Keyword = 1
    Identifier = 2
    Chord = 3

    @staticmethod
    def to_string(style):
        """Return the name for the style"""
        return {
            ChordProStyle.Default: 'Default',
            ChordProStyle.Keyword: 'Keyword',
            ChordProStyle.Identifier: 'Identifier',
            ChordProStyle.Chord: 'Chord'
        }.get(style)


class ChordProLexer(Qsci.QsciLexerCustom):

    def __init__(self, parent):
        super().__init__(parent)
        self.settings = QtCore.QSettings()
        self.settings.beginGroup('syntax')
        self.init_style()

    def _get_color(self, name, default):
        """Get a QColor object from the settings"""
        color = self.settings.value(name, default)
        if isinstance(color, str):
            if color.startswith('palette:'):
                palette_role = PALETTE_ROLES[color.split(':', 1)[1].lower()]
                color = QtWidgets.QApplication.palette().color(palette_role)
            else:
                color = QtGui.QColor(color)
        return color

    def _get_font(self, name):
        """Get a QFont object from the settings"""
        font = self.settings.value(name, None)
        if not font:
            font = QtGui.QFont('monospace')
        elif isinstance(font, str):
            font = QtGui.QFont.fromString(font)
        return font

    def init_style(self):
        """Set up the colours and fonts"""
        # Defaults
        self.setDefaultColor(self._get_color('default-foreground', 'palette:windowtext'))
        self.setDefaultPaper(self._get_color('default-background', 'palette:base'))
        self.setDefaultFont(self._get_font('default-font'))
        self.setColor(self._get_color('default-foreground', 'palette:windowtext'),
                      ChordProStyle.Default)
        self.setPaper(self._get_color('default-background', 'palette:base'),
                      ChordProStyle.Default)
        self.setFont(self._get_font('default-font'), ChordProStyle.Default)
        # Keywords
        kwfg = self._get_color('keywords-foreground', '#009fe3')
        if kwfg:
            self.setColor(kwfg, ChordProStyle.Keyword)
        kwbg = self._get_color('keywords-background', None)
        if kwbg:
            self.setPaper(kwbg, ChordProStyle.Keyword)
        kwft = self._get_font('keywords-font')
        if kwft:
            self.setFont(kwft, ChordProStyle.Keyword)
        # Identifiers
        idfg = self._get_color('identifiers-foreground', '#fdadff')
        if idfg:
            self.setColor(idfg, ChordProStyle.Identifier)
        idbg = self._get_color('identifiers-background', None)
        if idbg:
            self.setPaper(idbg, ChordProStyle.Identifier)
        idft = self._get_font('identifiers-font')
        if idft:
            self.setFont(idft, ChordProStyle.Identifier)
        # Chords
        chfg = self._get_color('chords-foreground', '#73ff6c')
        if chfg:
            self.setColor(chfg, ChordProStyle.Chord)
        chbg = self._get_color('chords-background', None)
        if chbg:
            self.setPaper(chbg, ChordProStyle.Chord)
        chft = self._get_font('chords-font')
        if chft:
            self.setFont(chft, ChordProStyle.Chord)

    def language(self):
        """Return the language name"""
        return "ChordPro"

    def description(self, style):
        """Return the name for the style number"""
        return ChordProStyle.to_string(style)

    def styleText(self, start, end):
        """Style the text"""

        keywords = ['verse', 'chorus', 'bridge'] + \
            [d for t in KNOWN_DIRECTIVES for d in t] + \
            ['start_of_' + vt for vt in KNOWN_VERSE_TYPES] + \
            ['end_of_' + vt for vt in KNOWN_VERSE_TYPES]
        is_directive = False
        is_identifier = False
        is_chord = False
        pattern = re.compile(r'\s+|\w+|\W')

        self.startStyling(start)
        text = self.parent().text()[start:end]

        token_list = [(token, len(bytearray(token, "utf-8"))) for token in pattern.findall(text)]

        for idx, token in enumerate(token_list):
            if token[0] == '{':
                is_directive = True
                self.setStyling(token[1], ChordProStyle.Keyword)
            elif is_directive and token[0] in keywords:
                self.setStyling(token[1], ChordProStyle.Keyword)
            elif is_directive and token[0] == ':':
                is_identifier = True
                self.setStyling(token[1], ChordProStyle.Keyword)
            elif is_directive and token[0] == '}':
                is_directive = False
                is_identifier = False
                self.setStyling(token[1], ChordProStyle.Keyword)
            elif is_identifier:
                self.setStyling(token[1], ChordProStyle.Identifier)
            elif token[0] == '[':
                is_chord = True
                self.setStyling(token[1], ChordProStyle.Chord)
            elif is_chord and token[0] == ']':
                is_chord = False
                self.setStyling(token[1], ChordProStyle.Chord)
            elif is_chord:
                self.setStyling(token[1], ChordProStyle.Chord)
            else:
                self.setStyling(token[1], ChordProStyle.Default)