# SPDX-License-Identifier: MIT
# Copyright 2021 Jookia <contact@jookia.org>

import ast_types

class Text:
    def __init__(self, value):
        self._value = value

    def __repr__(self):
        return "Text('%s')" % (self._value)

    def value(self):
        return self._value

    def Append(self, args):
        appendix = args[0]
        return Text(self.value() + " " + appendix.value())

def module_create(verbs):
    return ("module", verbs)
def module_dispatch(object, verb, args):
    (type, functions) = object
    return functions[verb](object, args)

def do_system_print(subject, args):
    print(args[0].value())
    return None
def do_system_read(subject, args):
    return Text(input())
system_module = module_create({
    "Print": do_system_print,
    "Read": do_system_read,
})

def resolve_value(env, value):
    if value.__class__ == ast_types.Reference:
        return env[value.value]
    elif value.__class__ == ast_types.Text:
        return Text(value.value)
    else:
        print("Unimplemented value: %s" % (value))

def run_statement(env, ast):
    subject = resolve_value(env, ast.subject)
    if ast.verb == None:
        return subject
    args = []
    for arg in ast.arguments:
        args.append(resolve_value(env, arg))
    if subject.__class__ == Text:
        return getattr(subject, ast.verb)(args)
    elif subject[0] == "module":
        return module_dispatch(subject, ast.verb, args)
    return None

def run_set(env, ast):
    env[ast.subject] = run_statement(env, ast.statement)
    return env[ast.subject]

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

def run_command(env, ast):
    if ast.__class__ == ast_types.Statement:
        return run_statement(env, ast)
    elif ast.__class__ == ast_types.Set:
        return run_set(env, ast)
    elif ast.__class__ == ast_types.Conditional:
        return run_conditional(env, ast)
    else:
        print("Unknown command %s" % (ast))
        return None

def run_ast(ast):
    env = {
        "System": system_module,
    }
    for command in ast:
        run_command(env, command)