__author__ = 'marcos.medeiros'


class RtfTemplate(object):
    """
    A file object that when read fills an RTF template with context data.
    The template variables must come between brackets "[]", instead of braces "{}",
    and will be interpreted with the builtin format rules (that means you can reference
    fields and elements, apply formatting rules (with comma ":") to the returned values, etc).

    Use two open brackets to represent an open bracket. Close brackets without an equivalent
    open bracket are repeated verbatim. Thus, to represent the text "[]", the original document
    must contain the text "[[]".

    Brackets were chosen because they aren't parsed by the RTF format, and thus can be inserted
    directly from WYSIWYG editors.
    """
    def __init__(self, file, context):
        """
        Open the template for reading, replacing the variables with the values from the
        given context.
        :param file: Template that will be read.
        :param context: Values that will be inserted at the place of the variables.
        """
        self.name = file
        self.template = open(file, 'r')
        self.encoding = self.template.encoding
        self.context = context
        self.pattern = ''
        self.brackets = 0
        self.partial = ''
        self.softspace = 0

    def format(self, template):
        """
        Formats the template with this object's context.
        Notice that a template may contain only part of a variable,
        what will make its value appear only at a later call of format.
        :param template: Original template text.
        :return: The formatted text.
        """
        ret = ''
        for c in template:
            if self.brackets == 0 and c != '[':
                ret += c
            else:
                if c == '[':
                    if self.brackets != 0:
                        self.pattern += c
                    self.brackets += 1
                    if self.brackets == 2 and self.pattern == '[':
                        ret += '['
                        self.brackets = 0
                        self.pattern = ''
                elif c == ']':
                    self.brackets -= 1
                    if self.brackets == 0:
                        ret += ('{'+self.pattern+'}').format(**self.context)
                        self.pattern = ''
                    else:
                        self.pattern += c
                else:
                    self.pattern += c
        return ret

    def _next_with(self, func):
        buf = func()
        f = self.format(buf)
        if buf and not f:
            return self._next_with(func)
        return f

    def next(self):
        return self._next_with(self.template.next)

    def __next__(self):
        return self._next_with(self.template.__next__)

    def _read_by(self, func, size):
        actual_size = size
        if self.partial:
            actual_size = size - len(self.partial)
        if actual_size < 0 < size:
            f = self.partial[0:size]
            self.partial = self.partial[size:]
            return f
        buf = func(actual_size)
        f = self.partial + self.format(buf)
        if buf and not f:
            return self.read(size)
        if 0 < size < len(f):
            self.partial = f[size:]
            return f[0:size]
        self.partial = ''
        return f

    def read(self, size=-1):
        return self._read_by(self.template.read, size)

    def readline(self, size):
        return self._read_by(self.template.readline, size)

    def close(self):
        self.template.close()

    def isatty(self):
        return self.template.isatty()

    def __iter__(self):
        return self

    @property
    def closed(self):
        return self.template.closed

    @property
    def newlines(self):
        return self.template.newlines

    @classmethod
    def format_into(cls, template, context, file):
        """
        Formats the template, writing the resulting data into the given file.
        :param template: Name of the template file.
        :param context: Context where variables will be evaluated.
        :param file: Name of the file that will be written with the formatted data.
        """
        t = RtfTemplate(template, context)
        f = open(file, 'w')
        for l in t:
            f.write(l)
        f.close()
        t.close()