# Copyright 2019 the authors.
# This file is part of Hy, which is free software licensed under the Expat
# license. See the LICENSE.

import os
import sys
import ast
import tempfile
import runpy
import importlib

from fractions import Fraction

import pytest

import hy
from hy.errors import HyTypeError
from hy.lex import hy_parse
from hy.lex.exceptions import LexException
from hy.compiler import hy_compile
from hy.importer import HyLoader, cache_from_source

try:
    from importlib import reload
except ImportError:
    from imp import reload


def test_basics():
    "Make sure the basics of the importer work"

    assert os.path.isfile('tests/resources/__init__.py')
    resources_mod = importlib.import_module('tests.resources')
    assert hasattr(resources_mod, 'kwtest')

    assert os.path.isfile('tests/resources/bin/__init__.hy')
    bin_mod = importlib.import_module('tests.resources.bin')
    assert hasattr(bin_mod, '_null_fn_for_import_test')


def test_runpy():
    # XXX: `runpy` won't update cached bytecode!  Don't know if that's
    # intentional or not.

    basic_ns = runpy.run_path('tests/resources/importer/basic.hy')
    assert 'square' in basic_ns

    main_ns = runpy.run_path('tests/resources/bin')
    assert main_ns['visited_main'] == 1
    del main_ns

    main_ns = runpy.run_module('tests.resources.bin')
    assert main_ns['visited_main'] == 1

    with pytest.raises(IOError):
        runpy.run_path('tests/resources/foobarbaz.py')


def test_stringer():
    _ast = hy_compile(hy_parse("(defn square [x] (* x x))"), '__main__')

    assert type(_ast.body[0]) == ast.FunctionDef


def test_imports():
    path = os.getcwd() + "/tests/resources/importer/a.hy"
    testLoader = HyLoader("tests.resources.importer.a", path)

    def _import_test():
        try:
            return testLoader.load_module()
        except:
            return "Error"

    assert _import_test() == "Error"
    assert _import_test() is not None


def test_import_error_reporting():
    "Make sure that (import) reports errors correctly."

    def _import_error_test():
        try:
            _ = hy_compile(hy_parse("(import \"sys\")"), '__main__')
        except HyTypeError:
            return "Error reported"

    assert _import_error_test() == "Error reported"
    assert _import_error_test() is not None


def test_import_error_cleanup():
    "Failed initial imports should not leave dead modules in `sys.modules`."

    with pytest.raises(hy.errors.HyMacroExpansionError):
        importlib.import_module('tests.resources.fails')

    assert 'tests.resources.fails' not in sys.modules


@pytest.mark.skipif(sys.dont_write_bytecode,
                    reason="Bytecode generation is suppressed")
def test_import_autocompiles():
    "Test that (import) byte-compiles the module."

    with tempfile.NamedTemporaryFile(suffix='.hy', delete=True) as f:
        f.write(b'(defn pyctest [s] (+ "X" s "Y"))')
        f.flush()

        pyc_path = cache_from_source(f.name)

        try:
            os.remove(pyc_path)
        except (IOError, OSError):
            pass

        test_loader = HyLoader("mymodule", f.name).load_module()

        assert hasattr(test_loader, 'pyctest')
        assert os.path.exists(pyc_path)

        os.remove(pyc_path)


def test_eval():
    def eval_str(s):
        return hy.eval(hy.read_str(s))

    assert eval_str('[1 2 3]') == [1, 2, 3]
    assert eval_str('{"dog" "bark" "cat" "meow"}') == {
        'dog': 'bark', 'cat': 'meow'}
    assert eval_str('(, 1 2 3)') == (1, 2, 3)
    assert eval_str('#{3 1 2}') == {1, 2, 3}
    assert eval_str('1/2') == Fraction(1, 2)
    assert eval_str('(.strip " fooooo   ")') == 'fooooo'
    assert eval_str(
        '(if True "this is if true" "this is if false")') == "this is if true"
    assert eval_str('(lfor num (range 100) :if (= (% num 2) 1) (pow num 2))') == [
        pow(num, 2) for num in range(100) if num % 2 == 1]


def test_reload():
    """Generate a test module, confirm that it imports properly (and puts the
    module in `sys.modules`), then modify the module so that it produces an
    error when reloaded.  Next, fix the error, reload, and check that the
    module is updated and working fine.  Rinse, repeat.

    This test is adapted from CPython's `test_import.py`.
    """

    def unlink(filename):
        os.unlink(source)
        bytecode = cache_from_source(source)
        if os.path.isfile(bytecode):
            os.unlink(bytecode)

    TESTFN = 'testfn'
    source = TESTFN + os.extsep + "hy"
    with open(source, "w") as f:
        f.write("(setv a 1)")
        f.write("(setv b 2)")

    sys.path.insert(0, os.curdir)
    try:
        mod = importlib.import_module(TESTFN)
        assert TESTFN in sys.modules
        assert mod.a == 1
        assert mod.b == 2

        # On WinXP, just replacing the .py file wasn't enough to
        # convince reload() to reparse it.  Maybe the timestamp didn't
        # move enough.  We force it to get reparsed by removing the
        # compiled file too.
        unlink(source)

        # Now damage the module.
        with open(source, "w") as f:
            f.write("(setv a 10)")
            f.write("(setv b (// 20 0))")

        with pytest.raises(ZeroDivisionError):
            reload(mod)

        # But we still expect the module to be in sys.modules.
        mod = sys.modules.get(TESTFN)
        assert mod is not None

        # We should have replaced a w/ 10, but the old b value should
        # stick.
        assert mod.a == 10
        assert mod.b == 2

        # Now fix the issue and reload the module.
        unlink(source)

        with open(source, "w") as f:
            f.write("(setv a 11)")
            f.write("(setv b (// 20 1))")

        reload(mod)

        mod = sys.modules.get(TESTFN)
        assert mod is not None

        assert mod.a == 11
        assert mod.b == 20

        # Now cause a `LexException`, and confirm that the good module and its
        # contents stick around.
        unlink(source)

        with open(source, "w") as f:
            # Missing paren...
            f.write("(setv a 11")
            f.write("(setv b (// 20 1))")

        with pytest.raises(LexException):
            reload(mod)

        mod = sys.modules.get(TESTFN)
        assert mod is not None

        assert mod.a == 11
        assert mod.b == 20

        # Fix it and retry
        unlink(source)

        with open(source, "w") as f:
            f.write("(setv a 12)")
            f.write("(setv b (// 10 1))")

        reload(mod)

        mod = sys.modules.get(TESTFN)
        assert mod is not None

        assert mod.a == 12
        assert mod.b == 10

    finally:
        del sys.path[0]
        if TESTFN in sys.modules:
            del sys.modules[TESTFN]
        unlink(source)


def test_circular():
    """Test circular imports by creating a temporary file/module that calls a
    function that imports itself."""
    sys.path.insert(0, os.path.abspath('tests/resources/importer'))
    try:
        mod = runpy.run_module('circular')
        assert mod['f']() == 1
    finally:
        sys.path.pop(0)


def test_shadowed_basename():
    """Make sure Hy loads `.hy` files instead of their `.py` counterparts (.e.g
    `__init__.py` and `__init__.hy`).
    """
    sys.path.insert(0, os.path.realpath('tests/resources/importer'))
    try:
        assert os.path.isfile('tests/resources/importer/foo/__init__.hy')
        assert os.path.isfile('tests/resources/importer/foo/__init__.py')
        assert os.path.isfile('tests/resources/importer/foo/some_mod.hy')
        assert os.path.isfile('tests/resources/importer/foo/some_mod.py')

        foo = importlib.import_module('foo')
        assert foo.__file__.endswith('foo/__init__.hy')
        assert foo.ext == 'hy'
        some_mod = importlib.import_module('foo.some_mod')
        assert some_mod.__file__.endswith('foo/some_mod.hy')
        assert some_mod.ext == 'hy'
    finally:
        sys.path.pop(0)


def test_docstring():
    """Make sure a module's docstring is loaded."""
    sys.path.insert(0, os.path.realpath('tests/resources/importer'))
    try:
        mod = importlib.import_module('docstring')
        expected_doc = ("This module has a docstring.\n\n"
                        "It covers multiple lines, too!\n")
        assert mod.__doc__ == expected_doc
        assert mod.a == 1
    finally:
        sys.path.pop(0)