'''Create JSON and loader from text source

Provides titles, links, inline and display mathematics.  Also provides
and index.

'''

import simplejson
import re

# These classes might be a good idea, but they get redefined later.
class _TextNode(str):
    ''' Generic text node.'''
    def __repr__(self):
        return '%s(%s)' % (self.__class__.__name__, super(_TextNode, self).__repr__())

class Text(_TextNode):
    pass

class Display(_TextNode):
    pass

class InLine(_TextNode):
    pass

class Link(_TextNode):
    pass

class Par(list):
    pass

# Regular expressions used for parsing.
page_split = re.compile(r'\s*\n\.page=').split
par_split = re.compile(r'\n\s*\n').split
display_split = re.compile(r'\$\$(.*?)\$\$', re.DOTALL).split
inline_split = re.compile(r'\$(.*?)\$', re.DOTALL).split
link_split = re.compile(r'\[(.*?)\]').split

class SplitDispatch(object):
    '''Split an object and dispatch functions on items.'''

    def __init__(self, split, f, g):

        self._split = split
        self._dispatch = [f, g]

    def __call__(self, str):
        i = 0
        for item in self._split(str):
            item = self._dispatch[i%2](item)
            i += 1

class parse_par(list):
    '''Convert a string to a list, that can be converted to JSON.'''
    def __init__(self, str):
        self.value = []
        SplitDispatch(display_split, self.non_display, self.display)(str)

    def non_display(self, str):
        SplitDispatch(inline_split, self.non_inline, self.inline)(str)

    def non_inline(self, str):
        SplitDispatch(link_split, self.text, self.link)(str)

    def display(self, str):
        self.append(Display(str))

    def inline(self, str):
        self.append(InLine(str))

    def link(self, str):
        self.append(Link(str))

    def text(self, str):
        self.append(Text(str))

def Text(str): return 'A' + str
def Link(str): return 'B' + str
def InLine(str): return 'C' + str
def Display(str): return 'D' + str

def doit(str):
    value = {}
    index = []
    
    for page_str in page_split(str)[1:]:

        a, body = page_str.split('\n', 1)
        key, title = a.split(' ', 1)
        index.append((key, title))

        page = []
        value[key] = page
        page.append('div')
        page.append(['h2', Text(title)])
        
        par_strs = par_split(body)
        for s in par_strs:
            page.append(['p'] + parse_par(s))

    index.sort()
    index_body = [['li', Link(item[0]), Text(' ' + item[1])]
                  for item in index]
    value['index'] = ['div', ['h2', Text('Index')], ['ul'] + index_body]

    return value

data = file('help.txt').read()
pages = doit(data)
file('help_data.json', 'wb').write('help_data=' + simplejson.dumps(pages))