import tab

class XMLTabber(tab.TokenStackTabber):
    close_tags = {'}': '{',
                  ')': '(',
                  ']': '['}

    def stack_append_const(self, c, n):
        if self.tab_stack[-1][0] != c:
            self.stack_append((c, self.tab_stack[-1][1] + n))
    def stack_pop_const(self, *c_args):
        if self.tab_stack[-1][0] in c_args:
            self.stack_pop()

    def base_indentation_level(self, y):
        return False

    def handle_token(self, prev_token, token, next_token, y=None):
        buffer = self.mode.window.buffer
        name = token.name
        s = token.string

        if name == 'opentag':
            if next_token is None:
                x = len(s) + 2
            else:
                x = next_token.start - token.start + 1
            # x is an offset from the current indention level
            self.stack_append_const('cont', x)
        elif name == 'gtc':
            self.stack_pop_const('cont')
            if prev_token is None:
                self.line_depth = self.tab_stack[-1][1]
        elif name == 'gt':
            self.stack_pop_const('cont')
            if prev_token is None:
                self.line_depth = self.tab_stack[-1][1]
            if self.tab_stack[-1][0] == 'close':
                self.stack_pop_const('close')
            else:
                self.stack_append(('tag', self.tab_stack[-1][1] + 4))
        elif name == 'ltc':
            self.stack_pop_const('cont')
            self.stack_pop_const('tag')
            l = self.tab_stack[-1][1]
            self.stack_append(('close', l))
            if prev_token is None:
                self.line_depth = l