import color, method, mode, lex, lex_diff, re

class Diff(mode.Fundamental):
    def __init__(self, w):
        mode.Fundamental.__init__(self, w)

        self.grammar = lex_diff.DiffGrammar()
        self.lexer   = lex.Lexer(self.grammar)

        self.add_action_and_bindings(DiffNextSection(), ('M-n', 'M-D_ARROW',))
        self.add_action_and_bindings(DiffPreviousSection(), ('M-p', 'M-U_ARROW',))

        self.colors = {
            'left':      color.build('red', 'default', 'bold'),
            'right':     color.build('blue', 'default', 'bold'),
            'seperator': color.build('magenta', 'default', 'bold'),
            'cvs metadata':  color.build('magenta', 'default', 'bold'),
            'svn metadata':  color.build('magenta', 'default', 'bold'),
            'location':  color.build('magenta', 'default', 'bold'),
        }

    def name(self):
        return "Diff"

class DiffNextSection(method.Method):
    re = re.compile("(?:^|(?<=\n))@@ [-+0-9a-z, ]* @@(?:$|\n)")
    def _execute(self, w, **vargs):
        cursor = w.logical_cursor()
        i = cursor.y + 1
        while i < len(w.buffer.lines):
            if self.re.match(w.buffer.lines[i]):
                w.goto_line(i)
                return
            i += 1

class DiffPreviousSection(method.Method):
    re = re.compile("(?:^|(?<=\n))@@ [-+0-9a-z, ]* @@(?:$|\n)")
    def _execute(self, w, **vargs):
        cursor = w.logical_cursor()
        i = cursor.y - 1
        while i >= 0:
            if self.re.match(w.buffer.lines[i]):
                w.goto_line(i)
                return
            i -= 1