#!/usr/bin/env python3
# SPDX-License-Identifier: MIT
# Copyright 2021 Jookia <contact@jookia.org>

import parse

def make_text(value):
    return {
        "type": "text",
        "_value": value,
    }

def do_system_print(env, args):
    print(args[0]["_value"])
    return None

def do_system_read(env, args):
    return make_text(input())

base_env = {
    "System": {
        "type": "module",
        "Print": do_system_print,
        "Read": do_system_read,
    }
}

def resolve_value(env, value):
    (type, value) = value
    if type == "reference":
        return env[value]
    elif type == "text":
        return make_text(value)
    else:
        print("Unimplemented value type: %s" % (type))

def run_statement(env, ast):
    subject = resolve_value(env, ast[1])
    command = subject[ast[2]]
    args = []
    for arg in ast[3]:
        args.append(resolve_value(env, arg))
    return command(env, args)

def run_set(env, ast):
    env[ast[1]] = run_statement(env, ast[2])
    return env[ast[1]]

def run_if(env, ast):
    print("Unimplemented if")
    return None

def run_command(env, ast):
    type = ast[0]
    if type == "statement":
        return run_statement(env, ast)
    elif type == "set":
        return run_set(env, ast)
    elif type == "if":
        return run_if(env, ast)
    else:
        print("Unknown command type %s" % (ast))
        return None

def main(args):
    if len(args) != 2:
        print("Usage: main.py FILENAME")
        return 1
    filename = args[1]
    code = open(filename).read()
    if code[0:2] == '#!':
        next_line = code.find('\n') + 1
        code = code[next_line:]
    tokens = parse.tokenize(code)
    parse.parser_reset(tokens)
    ast = parse.parse_file()
    if not ast:
        return 1
    for command in ast:
        run_command(base_env, command)
    return 0

if __name__ == "__main__":
    import sys
    sys.exit(main(sys.argv))