#!/usr/bin/env python3

import enum
import logging
import threading
import time
import subprocess

# TODO Update strategies (periodic, inotify file)
# TODO Section order (priority system maybe ?)
# TODO Allow deletion of Bar, BarGroup and Section for screen changes
# TODO Optimize to use write() calls instead of string concatenation (writing
# BarGroup strings should be a good compromise)
# TODO Use bytes rather than strings
# TODO Use default colors of lemonbar sometimes


class BarGroupType(enum.Enum):
    LEFT = 0
    RIGHT = 1
    # MID_LEFT = 2
    # MID_RIGHT = 3


class Bar:
    """
    One bar for each screen
    """

    # Constants
    FONT = "DejaVu Sans Mono for Powerline"

    @staticmethod
    def init():
        Section.init()

        cmd = ['lemonbar', '-f', Bar.FONT, '-b']
        Bar.process = subprocess.Popen(cmd, stdin=subprocess.PIPE)

        # Debug
        # Bar(0)
        Bar(1)

    # Class globals
    everyone = set()
    string = ""
    process = None

    def __init__(self, screen):
        assert isinstance(screen, int)
        self.screen = "%{S" + str(screen) + "}"
        self.groups = dict()

        for groupType in BarGroupType:
            group = BarGroup(groupType, self)
            self.groups[groupType] = group

        self.childsChanged = False

        self.everyone.add(self)

    @staticmethod
    def addSectionAll(section, group, screens=None):
        """
        .. note::
            Add the section before updating it for the first time.
        """
        assert isinstance(section, Section)
        assert isinstance(group, BarGroupType)
        # TODO screens selection
        for bar in Bar.everyone:
            bar.addSection(section, group=group)

    def addSection(self, section, group):
        assert isinstance(section, Section)
        assert isinstance(group, BarGroupType)
        self.groups[group].addSection(section)

    def update(self):
        if self.childsChanged:
            self.string = self.screen
            self.string += self.groups[BarGroupType.LEFT].string
            self.string += self.groups[BarGroupType.RIGHT].string

            self.childsChanged = False

    @staticmethod
    def updateAll():

        Bar.string = ""
        for bar in Bar.everyone:
            bar.update()
            Bar.string += bar.string
        # Color for empty sections
        Bar.string += BarGroup.color(*Section.EMPTY)

        print(Bar.string)
        Bar.process.stdin.write(bytes(Bar.string + '\n', 'utf-8'))
        Bar.process.stdin.flush()


class BarGroup:
    """
    One for each group of each bar
    """

    everyone = set()

    def __init__(self, groupType, parent):
        assert isinstance(groupType, BarGroupType)
        assert isinstance(parent, Bar)

        self.groupType = groupType
        self.parent = parent

        self.sections = list()
        self.string = ''
        self.parts = []

        #: One of the sections that had their theme or visibility changed
        self.childsThemeChanged = False

        #: One of the sections that had their text (maybe their size) changed
        self.childsTextChanged = False

        BarGroup.everyone.add(self)

    def addSection(self, section):
        self.sections.append(section)
        section.parents.add(self)

    ALIGNS = {BarGroupType.LEFT: "%{l}", BarGroupType.RIGHT: "%{r}"}

    @staticmethod
    def fgColor(color):
        return "%{F" + color + "}"

    @staticmethod
    def bgColor(color):
        return "%{B" + color + "}"

    @staticmethod
    def color(fg, bg):
        return BarGroup.fgColor(fg) + BarGroup.bgColor(bg)

    def update(self):
        if self.childsThemeChanged:
            parts = [BarGroup.ALIGNS[self.groupType]]

            secs = [sec for sec in self.sections if sec.visible]
            lenS = len(secs)
            for s in range(lenS):
                sec = secs[s]
                theme = Section.THEMES[sec.theme]
                if self.groupType == BarGroupType.LEFT:
                    oSec = secs[s + 1] if s < lenS - 1 else None
                else:
                    oSec = secs[s - 1] if s > 1 else None
                oTheme = Section.THEMES[oSec.theme] \
                    if oSec is not None else Section.EMPTY

                if self.groupType == BarGroupType.LEFT:
                    if s == 0:
                        parts.append(BarGroup.bgColor(theme[1]))
                    parts.append(BarGroup.fgColor(theme[0]))
                    parts.append(sec)
                    parts.append(BarGroup.color(theme[1], oTheme[1]) + "")
                else:
                    parts.append(BarGroup.fgColor(theme[1]) + "")
                    parts.append(BarGroup.color(*theme))
                    parts.append(sec)


            # TODO Concatenate successive strings
            self.parts = parts

        if self.childsTextChanged or self.childsThemeChanged:
            self.string = ""
            for part in self.parts:
                if isinstance(part, str):
                    self.string += part
                elif isinstance(part, Section):
                    self.string += part.curText

            self.parent.childsChanged = True

            self.childsThemeChanged = False
            self.childsTextChanged = False

    @staticmethod
    def updateAll():

        for group in BarGroup.everyone:

            group.update()

        Bar.updateAll()


class SectionThread(threading.Thread):
    def run(self):
        while Section.somethingChanged.wait():
            Section.updateAll()
            while len(Section.sizeChanging) > 0:
                time.sleep(0.1)
                Section.updateAll()


class Section:

    # TODO Update all of that to base16
    COLORS = ['#002b36', '#dc322f', '#859900', '#b58900', '#268bd2', '#6c71c4',
              '#2aa198', '#93a1a1', '#657b83', '#dc322f', '#859900', '#b58900',
              '#268bd2', '#6c71c4', '#2aa198', '#fdf6e3']
    FGCOLOR = '#93a1a1'
    BGCOLOR = '#002b36'

    THEMES = list()
    EMPTY = (FGCOLOR, BGCOLOR)

    @staticmethod
    def init():
        for t in range(8, 16):
            Section.THEMES.append((Section.COLORS[0], Section.COLORS[t]))

        Section.updateThread = SectionThread(daemon=True)
        Section.updateThread.start()

    #: Sections that do not have their destination size
    sizeChanging = set()
    somethingChanged = threading.Event()
    updateThread = None

    def __init__(self, theme=0):
        #: Displayed section
        #: Note: A section can be empty and displayed!
        self.visible = False

        self.theme = theme

        #: Displayed text
        self.curText = ''
        #: Displayed text size
        self.curSize = 0

        #: Destination text
        self.dstText = ''
        #: Destination size
        self.dstSize = 0

        #: Groups that have this section
        self.parents = set()

    def __str__(self):
        return "<{}><{}>{:01d}{}{:02d}/{:02d}" \
            .format(self.curText, self.dstText,
                    self.theme, "+" if self.visible else "-",
                    self.curSize, self.dstSize)

    def informParentsThemeChanged(self):
        for parent in self.parents:
            parent.childsThemeChanged = True

    def informParentsTextChanged(self):
        for parent in self.parents:
            parent.childsTextChanged = True

    def updateText(self, text):
        if len(text):
            self.dstText = ' {} '.format(text)
            self.dstSize = len(self.dstText)
        else:
            self.dstSize = 0

        if self.curSize == self.dstSize:
            self.curText = self.dstText
            self.informParentsTextChanged()
        else:
            Section.sizeChanging.add(self)
        Section.somethingChanged.set()

    def updateTheme(self, theme):
        assert isinstance(theme, int)
        assert theme < len(Section.THEMES)
        self.theme = theme
        self.informParentsThemeChanged()
        Section.somethingChanged.set()

    def updateVisibility(self, visibility):
        assert isinstance(visibility, bool)

        self.visible = visibility
        self.informParentsThemeChanged()
        Section.somethingChanged.set()

    @staticmethod
    def fit(text, size):
        t = len(text)
        return text[:size] if t >= size else text + " " * (size - t)

    def update(self):
        # TODO Might profit of a better logic
        if not self.visible:
            self.updateVisibility(True)
            return

        if self.dstSize > self.curSize:
            self.curSize += 1
        elif self.dstSize < self.curSize:
            self.curSize -= 1
        else:
            # Visibility toggling must be done one step after curSize = 0
            if self.dstSize == 0:
                self.updateVisibility(False)
            Section.sizeChanging.remove(self)
            return

        self.curText = Section.fit(self.dstText, self.curSize)
        self.informParentsTextChanged()

    @staticmethod
    def updateAll():
        """
        Process all sections for text size changes
        """

        for sizeChanging in Section.sizeChanging.copy():
            sizeChanging.update()

        BarGroup.updateAll()

        Section.somethingChanged.clear()


if __name__ == '__main__':
    Bar.init()
    sec = Section(0)
    sech = Section(1)
    sec1 = Section(2)
    sec2 = Section(3)
    sec2h = Section(4)
    sec3 = Section(5)
    Bar.addSectionAll(sec, BarGroupType.LEFT)
    Bar.addSectionAll(sech, BarGroupType.LEFT)
    Bar.addSectionAll(sec1, BarGroupType.LEFT)
    Bar.addSectionAll(sec2, BarGroupType.RIGHT)
    Bar.addSectionAll(sec2h, BarGroupType.RIGHT)
    Bar.addSectionAll(sec3, BarGroupType.RIGHT)

    time.sleep(1)
    sec.updateText("A")
    time.sleep(1)
    sec.updateText("")
    time.sleep(1)
    sec.updateText("Hello")
    sec1.updateText("world!")
    sec2.updateText("Salut")
    sec2h.updateText("le")
    sec3.updateText("monde !")
    time.sleep(3)
    sech.updateText("the")
    sec2h.updateText("")
    time.sleep(2)
    sec.updateText("")
    sech.updateText("")
    sec1.updateText("")
    sec2.updateText("")
    sec2h.updateText("")
    sec3.updateText("")
    time.sleep(5)