import io

import pytest

from pywasm import binary
from pywasm import Runtime

from .helpers import wat2wasm

def run(code_wat):
    code_wasm = wat2wasm(code_wat)
    module = binary.Module.from_reader(io.BytesIO(code_wasm))

    runtime = Runtime(module, {}, {})

    out_put = runtime.exec('testEntry', [])
    return (runtime, out_put)

@pytest.mark.parametrize('size,offset,exp_out_put', [
    ('32', 0,         0x3020100),
    ('32', 1,         0x4030201),
    ('64', 0, 0x706050403020100),
    ('64', 2, 0x908070605040302),
])
def test_i32_64_load(size, offset, exp_out_put):
    code_wat = f"""
  (module
    (memory 1)
     (data (memory 0) (i32.const 0) "\\00\\01\\02\\03\\04\\05\\06\\07\\08\\09\\10")

    (func (export "testEntry") (result i{size})
      i32.const {offset}
      i{size}.load
      return ))
"""

    (_, out_put) = run(code_wat)
    assert exp_out_put == out_put

def test_load_then_store():
    code_wat = """
  (module
    (memory 1)
    (data (memory 0) (i32.const 0) "\\04\\00\\00\\00")

    (func (export "testEntry") (result i32) (local $my_memory_value i32)
      ;; Load i32 from address 0
      i32.const 0
      i32.load

      ;; Add 8 to the loaded value
      i32.const 8
      i32.add

      local.set $my_memory_value

      ;; Store back to the memory
      i32.const 0
      local.get $my_memory_value
      i32.store

      ;; Return something
      i32.const 9
      return ))
"""
    (runtime, out_put) = run(code_wat)

    assert 9 == out_put

    assert (b'\x0c'+ b'\00' * 23) == runtime.store.mems[0].data[:24]