#!/usr/bin/python3

# -------------------------------------------------------------------------------
# Copyleft (K) 2008 by Jose M. Rodriguez de la Rosa
#
# Simple ASCII to BASIC tokenizer
#
# Implements a simple (really simple) ZX Spectrum BASIC tokenizer
# This will convert a simple ASCII text to a ZX spectrum BASIC bytes program
# -------------------------------------------------------------------------------

from src import outfmt as tzx
from src.api import fp

ENTER = 0x0D

TOKENS = {
    "LOAD": 239,
    "POKE": 244,
    "PRINT": 245,
    "RUN": 247,
    "PEEK": 190,
    "USR": 192,
    "LINE": 202,
    "CODE": 175,
    "AT": 172,
    "RANDOMIZE": 249,
    "CLS": 251,
    "CLEAR": 253,
    "PAUSE": 242,
    "LET": 241,
    "INPUT": 238,
    "READ": 227,
    "DATA": 228,
    "RESTORE": 229,
    "NEW": 230,
    "OUT": 223,
    "BEEP": 215,
    "INK": 217,
    "PAPER": 218,
    "BORDER": 231,
    "REM": 234,
    "FOR": 235,
    "TO": 204,
    "NEXT": 243,
    "RETURN": 254,
    "GOTO": 236,
    "GO SUB": 237,
}


class Basic:
    """Class for a simple BASIC tokenizer"""

    def __init__(self):
        self.bytes = []  # Array of bytes containing a ZX Spectrum BASIC program
        self.current_line = 0  # Current basic_line

    def line_number(self, number):
        """Returns the bytes for a line number.
        This is BIG ENDIAN for the ZX Basic
        """
        numberH = (number & 0xFF00) >> 8
        numberL = number & 0xFF

        return [numberH, numberL]

    def numberLH(self, number):
        """Returns the bytes for 16 bits number.
        This is LITTLE ENDIAN for the ZX Basic
        """
        numberH = (number & 0xFF00) >> 8
        numberL = number & 0xFF

        return [numberL, numberH]

    def number(self, number):
        """Returns a floating point (or integer) number for a BASIC
        program. That is: It's ASCII representation followed by 5 bytes
        in floating point or integer format (if number in (-65535 + 65535)
        """
        s = [ord(x) for x in str(number)] + [14]  # Bytes of string representation in bytes

        if number == int(number) and abs(number) < 65536:  # integer form?
            sign = 0xFF if number < 0 else 0
            b = [0, sign] + self.numberLH(number) + [0]
        else:  # Float form
            (C, ED, LH) = fp.immediate_float(number)
            C = C[:2]  # Remove 'h'
            ED = ED[:4]  # Remove 'h'
            LH = LH[:4]  # Remove 'h'

            b = [int(C, 16)]  # Convert to BASE 10
            b += [int(ED[:2], 16), int(ED[2:], 16)]
            b += [int(LH[:2], 16), int(LH[2:], 16)]

        return s + b

    def token(self, string):
        """Return the token for the given word"""
        string = string.upper()

        return [TOKENS[string]]

    def literal(self, string):
        """Return the current string "as is"
        in bytes
        """
        return [ord(x) for x in string]

    def parse_sentence(self, string):
        """Parses the given sentence. BASIC commands must be
        types UPPERCASE and as SEEN in ZX BASIC. e.g. GO SUB for gosub, etc...
        """

        result = []

        def shift(string_):
            """Returns first word of a string, and remaining"""
            string_ = string_.strip()  # Remove spaces and tabs

            if not string_:  # Avoid empty strings
                return "", ""

            i = string_.find(" ")
            if i == -1:
                command_ = string_
                string_ = ""
            else:
                command_ = string_[:i]
                string_ = string_[i:]

            return command_, string_

        command, string = shift(string)
        while command != "":
            result += self.token(command)

    def sentence_bytes(self, sentence):
        """Return bytes of a sentence.
        This is a very simple parser. Sentence is a list of strings and numbers.
        1st element of sentence MUST match a token.
        """
        result = [TOKENS[sentence[0]]]

        for i in sentence[1:]:  # Remaining bytes
            if isinstance(i, str):
                result.extend(self.literal(i))
            elif isinstance(i, float) or isinstance(i, int):  # A number?
                result.extend(self.number(i))
            else:
                result.extend(i)  # Must be another thing

        return result

    def line(self, sentences, line_number=None):
        """Return the bytes for a basic line.
        If no line number is given, current one + 10 will be used
        Sentences if a list of sentences
        """
        if line_number is None:
            line_number = self.current_line + 10
        self.current_line = line_number

        sep = []
        result = []
        for sentence in sentences:
            result.extend(sep)
            result.extend(self.sentence_bytes(sentence))
            sep = [ord(":")]

        result.extend([ENTER])
        result = self.line_number(line_number) + self.numberLH(len(result)) + result

        return result

    def add_line(self, sentences, line_number=None):
        """Add current line to the output.
        See self.line() for more info
        """
        self.bytes += self.line(sentences, line_number)


if __name__ == "__main__":
    # Only as a test if invoked from command line
    a = Basic()
    a.add_line([["CLEAR", 31999]])
    a.add_line([["POKE", 23610, ",", 255]])
    a.add_line([["LOAD", '""', a.token("CODE")]])
    a.add_line([["RANDOMIZE", a.token("USR"), 32000]])

    t = tzx.TZX()
    t.save_program("test.tzx", a.bytes, line=1)
    t.dump("tzxtest.tzx")
