import wx
from eval import arithmetic_eval
from utils import typename


class MathEntry(wx.TextCtrl):

    def __init__(self, *args, value="", **kwargs):
        if "style" in kwargs:
            kwargs["style"] |= wx.TE_PROCESS_ENTER
        else:
            kwargs["style"] = wx.TE_PROCESS_ENTER

        self.value_type = type(value)
        value = str(value)
        wx.TextCtrl.__init__(self, *args, value=value, **kwargs)

        self._alarm = False
        self._last_good_value = self.GetValue()

        self.Bind(wx.EVT_TEXT_ENTER, self.on_enter)
        self.Bind(wx.EVT_KEY_UP, self.on_escape)


    def GetValue(self):
        val = super().GetValue()

        if val == "": #TODO?
            return None

        if val == "None": #TODO?
            return None

        try:
            val = self.value_type(val)
        except (ValueError, TypeError) as e:
            print(e)

        return val


    def SetValue(self, val):
        self.value_type = type(val)
        val = str(val)
        super().SetValue(val)


    def on_enter(self, event):
        val = super().GetValue()

        self._unset_alarm()

        try:
            val = arithmetic_eval(val)
            self.value_type = type(val)
        except SyntaxError as e:
            en = typename(e)
            msg = e.args[0]
            msg = f"{en}: {msg}"
            self._set_alarm(msg)
            self.SetInsertionPoint(e.offset)
        except Exception as e:
            en = typename(e)
            msg = f"{en}: {e}"
            self._set_alarm(msg)
            self.SetInsertionPointEnd()
        else:
            self.SetValue(val)
            self._last_good_value = val

        event.Skip()


    def on_escape(self, event):
        code = event.GetKeyCode()
        if code != wx.WXK_ESCAPE:
            event.Skip()
            return

        if self._alarm:
            self.SetValue(self._last_good_value)
            self._unset_alarm()


    def _set_alarm(self, msg):
        self._alarm = True
        self.SetToolTip(msg)
        self.SetForegroundColour(wx.RED)

    def _unset_alarm(self):
        self._alarm = False
        self.SetToolTip(None)
        self.SetForegroundColour(wx.NullColour)


    def clear(self):
        super().SetValue("")