from emis_funky_funktions import *
from typing import Collection, Sequence, TypeAlias

from ir import Expression, ReplHole, subst_all
from genir import json_to_ir
from types_ import BUILTINS_CONTEXT

import json
from dataclasses import dataclass
from operator import add

def evaluate(expr: Expression) -> Expression:
	"""
	>>> funktion = Function((
	...    (SPattern(NamePattern('n')), (
	...        Application((
	...            Variable('+'),
	...            Variable('n'),
	...            Variable('n'),
	...        ))
	...    )),
	...    (NamePattern('0'), (
	...        Int(1312)
	...    )),
	... ))
	>>> evaluate(Application((funktion, Int(3))))
	4
	>>> evaluate(Application((funktion, Int(0))))
	1312
	"""
	if expr.is_value():
		return expr
	else:
		match expr.step():
			case Some(next):
				return evaluate(next)
			case None:
				raise AssertionError('Evaluate called on a value which cannot step:', expr)
	raise Exception('Unreachable')

def repl_expr(expr: Expression, bindings: ReplHole = ReplHole(BUILTINS_CONTEXT)):
	expr_subst = subst_all(bindings.val_bindings, expr)
	result = evaluate(expr_subst)
	if isinstance(result, ReplHole):
		print('Environment updated\n')
		print(result.typ_bindings)
		repl(result)
	else:
		print(result, end='\n\n')
		repl(bindings)

def repl(bindings: ReplHole = ReplHole(BUILTINS_CONTEXT)):
	print('Enter a JSON expression:')
	try:
		expr = input('-> ')
	except EOFError:
		print('<exit>')
		return
	try:
		ast = json.loads(expr)
	except json.decoder.JSONDecodeError as e:
		print(f'Bad json: ', e.args[0], end='\n\n')
		return repl(bindings)
	# TODO handle this
	new_expr, new_ty, substs = unwrap_r(json_to_ir(ast, bindings.typ_bindings))
	repl_expr(new_expr, bindings)

if __name__ == '__main__':
	import doctest
	doctest.testmod()