import io
import os
import subprocess
import sys

from tempfile import NamedTemporaryFile

import pywasm

import wasm3

import wasmer
import wasmer_compiler_cranelift

import wasmtime

from py2wasm.utils import our_process, process

DASHES = '-' * 16

def wat2wasm(code_wat):
    path = os.environ.get('WAT2WASM', 'wat2wasm')

    with NamedTemporaryFile('w+t') as input_fp:
        input_fp.write(code_wat)
        input_fp.flush()

        with NamedTemporaryFile('w+b') as output_fp:
            subprocess.run(
                [
                    path,
                    input_fp.name,
                    '-o',
                    output_fp.name,
                ],
                check=True,
            )

            output_fp.seek(0)

            return output_fp.read()

class SuiteResult:
    def __init__(self):
        self.log_int32_list = []
        self.returned_value = None

    def callback_log_int32(self, store, value):
        del store # auto passed by pywasm

        self.log_int32_list.append(value)

    def make_imports(self):
        return {
            'console': {
                'logInt32': self.callback_log_int32,
            }
        }

class Suite:
    def __init__(self, code_py, test_name):
        self.code_py = code_py
        self.test_name = test_name

    def run_code(self, *args):
        """
        Compiles the given python code into wasm and
        then runs it

        Returned is an object with the results set
        """
        our_module = our_process(self.code_py, self.test_name)
        assert self.code_py == '\n' + our_module.render() # \n for formatting in tests

        code_wat = process(self.code_py, self.test_name)

        sys.stderr.write(f'{DASHES} Assembly {DASHES}\n')

        line_list = code_wat.split('\n')
        line_no_width = len(str(len(line_list)))
        for line_no, line_txt in enumerate(line_list):
            sys.stderr.write('{}  {}\n'.format(
                str(line_no + 1).zfill(line_no_width),
                line_txt,
            ))

        code_wasm = wat2wasm(code_wat)

        return _run_pywasm3(code_wasm, args)

def _run_pywasm(code_wasm, args):
    # https://pypi.org/project/pywasm/
    result = SuiteResult()

    module = pywasm.binary.Module.from_reader(io.BytesIO(code_wasm))

    runtime = pywasm.Runtime(module, result.make_imports(), {})

    sys.stderr.write(f'{DASHES} Memory (pre run)  {DASHES}\n')
    _dump_memory(runtime.store.mems[0].data)

    result.returned_value = runtime.exec('testEntry', args)

    sys.stderr.write(f'{DASHES} Memory (post run) {DASHES}\n')
    _dump_memory(runtime.store.mems[0].data)

    return result

def _run_pywasm3(code_wasm, args):
    # https://pypi.org/project/pywasm3/
    result = SuiteResult()

    env = wasm3.Environment()

    mod = env.parse_module(code_wasm)

    rtime = env.new_runtime(1024 * 1024)
    rtime.load(mod)

    sys.stderr.write(f'{DASHES} Memory (pre run)  {DASHES}\n')
    _dump_memory(rtime.get_memory(0).tobytes())

    result.returned_value = rtime.find_function('testEntry')(*args)

    sys.stderr.write(f'{DASHES} Memory (post run) {DASHES}\n')
    _dump_memory(rtime.get_memory(0).tobytes())

    return result

def _run_wasmtime(code_wasm, args):
    # https://pypi.org/project/wasmtime/
    result = SuiteResult()

    store = wasmtime.Store()

    module = wasmtime.Module(store.engine, code_wasm)

    instance = wasmtime.Instance(store, module, [])

    sys.stderr.write(f'{DASHES} Memory (pre run)  {DASHES}\n')
    sys.stderr.write('<Not available on wasmtime>\n')

    result.returned_value = instance.exports(store)['testEntry'](store, *args)

    sys.stderr.write(f'{DASHES} Memory (post run) {DASHES}\n')
    sys.stderr.write('<Not available on wasmtime>\n')

    return result

def _run_wasmer(code_wasm, args):
    # https://pypi.org/project/wasmer/
    result = SuiteResult()

    store = wasmer.Store(wasmer.engine.JIT(wasmer_compiler_cranelift.Compiler))

    # Let's compile the module to be able to execute it!
    module = wasmer.Module(store, code_wasm)

    # Now the module is compiled, we can instantiate it.
    instance = wasmer.Instance(module)

    sys.stderr.write(f'{DASHES} Memory (pre run)  {DASHES}\n')
    sys.stderr.write('<Not available on wasmer>\n')

    # Call the exported `sum` function.
    result.returned_value = instance.exports.testEntry(*args)

    sys.stderr.write(f'{DASHES} Memory (post run) {DASHES}\n')
    sys.stderr.write('<Not available on wasmer>\n')

    return result

def _dump_memory(mem):
    line_width = 16

    prev_line = None
    skip = False
    for idx in range(0, len(mem), line_width):
        line = ''
        for idx2 in range(0, line_width):
            line += f'{mem[idx + idx2]:02X}'
            if idx2 % 2 == 1:
                line += ' '

        if prev_line == line:
            if not skip:
                sys.stderr.write('**\n')
            skip = True
        else:
            sys.stderr.write(f'{idx:08x} {line}\n')

        prev_line = line