1 files changed, 164 insertions, 0 deletions
diff --git a/attoconf/help.py b/attoconf/help.py
new file mode 100644
index 0000000..a2379a6
--- /dev/null
+++ b/attoconf/help.py
@@ -0,0 +1,164 @@
+#   Copyright 2013 Ben Longbons <b.r.longbons@gmail.com>
+#
+#   This file is part of attoconf.
+#
+#   attoconf is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   attoconf is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with attoconf.  If not, see <http://www.gnu.org/licenses/>.
+
+
+
+def put_line_in_width(file, line, width, indent):
+    ''' Print a line with wrapping.
+    '''
+    line = line.rstrip(' ')
+    if len(line) <= width or ' ' not in line.lstrip(' '):
+        # this is not just an optimization
+        file.writelines([line, '\n'])
+        return
+    line += ' '
+    indents = indent * ' '
+
+    initial_spaces = len(line) - len(line.lstrip(' '))
+    while line.lstrip():
+        space = line.rfind(' ', initial_spaces, width + 1)
+        if space == -1:
+            space = line.find(' ', initial_spaces)
+        if space == -1:
+            space = len(line)
+        file.writelines([line[:space], '\n'])
+        line = indents + line[space+1:].lstrip(' ')
+        initial_spaces = indent
+
+
+class HelpSection(object):
+    ''' A help section contains some header lines and some related options.
+    '''
+    __slots__ = (
+            'headers',
+            'options',
+    )
+    def __init__(self):
+        ''' Create an empty help section.
+        '''
+        self.headers = []
+        self.options = []
+
+    def add_text(self, text, hidden):
+        ''' Add a header line.
+        '''
+        self.headers.append((hidden, text))
+
+    def add_option(self, name, text, hidden):
+        ''' Add an option with its description.
+        '''
+        self.options.append((hidden, name, text))
+
+    def print(self, file, hidden, width):
+        ''' Format (some of) the help text prettily.
+        '''
+        if self.options:
+            for oh, name, ht in self.options:
+                if oh <= hidden:
+                    break
+            else:
+                return False
+
+        # options longer than this will be split into multiple lines
+        split_width = width / 4 - 2
+        # longest option
+        longest_opt = 0
+        for oh, name, ht in self.options:
+            if oh > hidden:
+                continue
+            l = len(name) + 2
+            if l > split_width:
+                continue
+            if l > longest_opt:
+                longest_opt = l
+        if longest_opt == 0:
+            longest_opt = int(split_width)
+
+        for oh, ht in self.headers:
+            if oh > hidden:
+                continue
+            put_line_in_width(file, ht, width, 0)
+
+        for oh, name, ht in self.options:
+            if oh > hidden:
+                continue
+            # no, it's not really that simple
+            if len(name) > longest_opt:
+                file.writelines(['  ', name, '\n'])
+                name = ''
+            line = '  %-*s%s' % (longest_opt, name, ht)
+            put_line_in_width(file, line, width, longest_opt + 2)
+
+        return True
+
+
+def detect_terminal_width(fd, DEFAULT_WIDTH=float('inf')):
+    ''' Detect the width of a terminal.
+    '''
+    import os
+    import shutil
+
+    if isinstance(fd, int):
+        try:
+            return os.get_terminal_size(fd)
+        except OSError(...):
+            return DEFAULT_WIDTH
+    else:
+        return shutil.get_terminal_size(fallback=(DEFAULT_WIDTH, 24)).columns
+
+
+class Help(object):
+    ''' Help collects the set of flavor text and option descriptions
+        related to arguments.
+    '''
+    __slots__ = (
+            'sections',
+    )
+    def __init__(self):
+        ''' Help does not take any arguments during construction.
+        '''
+        self.sections = []
+
+    def add_text(self, help, hidden):
+        ''' Add a header line.
+
+            This creates a new section if the last line wasn't a header.
+        '''
+        if not self.sections or self.sections[-1].options:
+            self.sections.append(HelpSection())
+        self.sections[-1].add_text(help, hidden)
+
+    def add_option(self, name, help, hidden):
+        ''' Add an option with its description to the current section.
+
+            This creates a new section only if it is first.
+        '''
+        if not self.sections:
+            self.sections.append(HelpSection())
+        self.sections[-1].add_option(name, help, hidden)
+
+    def print(self, file, hidden, width=0):
+        ''' Print all the help at the given level of hidden-ness.
+        '''
+        if width == 0:
+            width = detect_terminal_width(file)
+        if width < 20:
+            width = 80
+
+        for s in self.sections:
+            if s.print(file, hidden, width):
+                file.write('\n')