"""Test Home Assistant json utility functions."""
from json import JSONEncoder
import os
import unittest
from unittest.mock import Mock
import sys
from tempfile import mkdtemp

import pytest

from homeassistant.util.json import (
    SerializationError, load_json, save_json)
from homeassistant.exceptions import HomeAssistantError


# Test data that can be saved as JSON
TEST_JSON_A = {"a": 1, "B": "two"}
TEST_JSON_B = {"a": "one", "B": 2}
# Test data that can not be saved as JSON (keys must be strings)
TEST_BAD_OBJECT = {("A",): 1}
# Test data that can not be loaded as JSON
TEST_BAD_SERIALIED = "THIS IS NOT JSON\n"
TMP_DIR = None


def setup():
    """Set up for tests."""
    global TMP_DIR
    TMP_DIR = mkdtemp()


def teardown():
    """Clean up after tests."""
    for fname in os.listdir(TMP_DIR):
        os.remove(os.path.join(TMP_DIR, fname))
    os.rmdir(TMP_DIR)


def _path_for(leaf_name):
    return os.path.join(TMP_DIR, leaf_name+".json")


def test_save_and_load():
    """Test saving and loading back."""
    fname = _path_for("test1")
    save_json(fname, TEST_JSON_A)
    data = load_json(fname)
    assert data == TEST_JSON_A


# Skipped on Windows
@unittest.skipIf(sys.platform.startswith('win'),
                 "private permissions not supported on Windows")
def test_save_and_load_private():
    """Test we can load private files and that they are protected."""
    fname = _path_for("test2")
    save_json(fname, TEST_JSON_A, private=True)
    data = load_json(fname)
    assert data == TEST_JSON_A
    stats = os.stat(fname)
    assert stats.st_mode & 0o77 == 0


def test_overwrite_and_reload():
    """Test that we can overwrite an existing file and read back."""
    fname = _path_for("test3")
    save_json(fname, TEST_JSON_A)
    save_json(fname, TEST_JSON_B)
    data = load_json(fname)
    assert data == TEST_JSON_B


def test_save_bad_data():
    """Test error from trying to save unserialisable data."""
    fname = _path_for("test4")
    with pytest.raises(SerializationError):
        save_json(fname, TEST_BAD_OBJECT)


def test_load_bad_data():
    """Test error from trying to load unserialisable data."""
    fname = _path_for("test5")
    with open(fname, "w") as fh:
        fh.write(TEST_BAD_SERIALIED)
    with pytest.raises(HomeAssistantError):
        load_json(fname)


def test_custom_encoder():
    """Test serializing with a custom encoder."""
    class MockJSONEncoder(JSONEncoder):
        """Mock JSON encoder."""

        def default(self, o):
            """Mock JSON encode method."""
            return "9"

    fname = _path_for("test6")
    save_json(fname, Mock(), encoder=MockJSONEncoder)
    data = load_json(fname)
    assert data == "9"