import wx
import wx.grid
from model import session

class Column(object):

    def __init__(self, id, title=None, width=None, getter=None):
        self.id = id
        self.title = title if title else id

        default_getter = lambda x: getattr(x, self.id, None)
        self.getter = getter if getter else default_getter
        self.width = width if width else -2


class SAGridAdapter(wx.grid.PyGridTableBase):
    BUFFER_LEN = 200

    def __init__(self, columns, query):
        super(SAGridAdapter, self).__init__()
        self.columns = columns
        self.query = query
        self.buffer_start = 0
        self.buffer = ()
        self.rows = 0
        self.odd = wx.grid.GridCellAttr()
        self.odd.SetBackgroundColour("snow")
        self.odd.SetReadOnly(True)
        self.even = wx.grid.GridCellAttr()
        self.even.SetBackgroundColour("lightcyan2")
        self.even.SetReadOnly(True)
        self.selected = wx.grid.GridCellAttr()
        self.selected.SetBackgroundColour((135,206,250))
        self.selected.SetReadOnly(True)
        self.refresh()

    def column_width(self):
        return [x.width for x in self.columns]

    def refresh(self):
        self.rows = self.query.count()
        self._move_buffer()

    def _move_buffer(self):
        self.buffer = self.query[self.buffer_start:self.buffer_start+self.BUFFER_LEN]

    def __getitem__(self, index):
        n = index - self.buffer_start
        if n >= 0 and n < min(self.BUFFER_LEN, self.rows):
            return self.buffer[n]
        else:
            self.buffer_start = index - self.BUFFER_LEN / 2
            if self.buffer_start < 0:
                self.buffer_start = 0
            self._move_buffer()
            return self.buffer[index-self.buffer_start]

    def GetNumberRows(self):
        return self.rows

    def GetNumberCols(self):
        return len(self.columns)

    def GetColLabelValue(self, col):
        return self.columns[col].title

    def GetRowLabelValue(self, row):
        pass

    def IsEmptyCell(self, row, col):
        return self.columns[col].getter(self[row]) == None

    def GetValue(self, row, col):
        return self.columns[col].getter(self[row])

    def SetValue(self, row, col, value):
        pass

    def GetAttr(self, row, col, kind):
        curr_row = self.GetView().GetGridCursorRow()
        if row == curr_row or (curr_row == -1 and row == 0):
            attr = self.selected
        else:
            attr = [self.even, self.odd][row % 2]
        attr.IncRef()
        return attr