# SPDX-License-Identifier: LGPL-2.1-only
# Copyright 2022 Jookia <contact@jookia.org>

from src.syntax import Syntax, SyntaxType


# Removes whitespace syntax tokens
def strip_whitespace(syntax):
    output = []
    for s in syntax:
        if s.type != SyntaxType.TOKEN or s.value not in ["\n", " "]:
            output.append(s)
    return output


# Reads a token, possibly of a certain value
def read_token(stream, value):
    s = stream.pop()
    if s is None:
        return None
    elif s.type != SyntaxType.TOKEN:
        return None
    elif value is not None and s.value != value:
        return None
    return s


# Parses a text syntax node
def parse_text(stream):
    buffer = ""
    s = read_token(stream, "StartText")
    if s is None:
        return None
    location = s.location
    # Parse following tokens
    while True:
        s = read_token(stream, None)
        if s is None:
            return None
        # Don't allow StartText in text
        elif s.value in ["StartText"]:
            return None
        # EndText found, end things
        elif s.value == "EndText":
            break
        else:
            buffer += s.value
    value = buffer.strip("\n\t ")
    type = SyntaxType.TEXT
    return Syntax(value, location, type)


# Parses tokens
def parse(tokens):
    stripped = strip_whitespace(tokens)
    return stripped