# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.


import base64
import calendar
import json
import os
import time

import iso8601

import pretend

import pytest

from cryptography.fernet import Fernet, InvalidToken, MultiFernet
from cryptography.hazmat.primitives.ciphers import algorithms, modes

import cryptography_vectors


def json_parametrize(keys, filename):
    vector_file = cryptography_vectors.open_vector_file(
        os.path.join("fernet", filename), "r"
    )
    with vector_file:
        data = json.load(vector_file)
        return pytest.mark.parametrize(
            keys,
            [tuple([entry[k] for k in keys]) for entry in data],
            ids=[f"{filename}[{i}]" for i in range(len(data))],
        )


@pytest.mark.supported(
    only_if=lambda backend: backend.cipher_supported(
        algorithms.AES(b"\x00" * 32), modes.CBC(b"\x00" * 16)
    ),
    skip_message="Does not support AES CBC",
)
class TestFernet:
    @json_parametrize(
        ("secret", "now", "iv", "src", "token"),
        "generate.json",
    )
    def test_generate(self, secret, now, iv, src, token, backend):
        f = Fernet(secret.encode("ascii"), backend=backend)
        actual_token = f._encrypt_from_parts(
            src.encode("ascii"),
            calendar.timegm(iso8601.parse_date(now).utctimetuple()),
            bytes(iv),
        )
        assert actual_token == token.encode("ascii")

    @json_parametrize(
        ("secret", "now", "src", "ttl_sec", "token"),
        "verify.json",
    )
    def test_verify(
        self, secret, now, src, ttl_sec, token, backend, monkeypatch
    ):
        # secret & token are both str
        f = Fernet(secret.encode("ascii"), backend=backend)
        current_time = calendar.timegm(iso8601.parse_date(now).utctimetuple())
        payload = f.decrypt_at_time(
            token,  # str
            ttl=ttl_sec,
            current_time=current_time,
        )
        assert payload == src.encode("ascii")

        payload = f.decrypt_at_time(
            token.encode("ascii"),  # bytes
            ttl=ttl_sec,
            current_time=current_time,
        )
        assert payload == src.encode("ascii")

        monkeypatch.setattr(time, "time", lambda: current_time)

        payload = f.decrypt(token, ttl=ttl_sec)  # str
        assert payload == src.encode("ascii")

        payload = f.decrypt(token.encode("ascii"), ttl=ttl_sec)  # bytes
        assert payload == src.encode("ascii")

    @json_parametrize(("secret", "token", "now", "ttl_sec"), "invalid.json")
    def test_invalid(self, secret, token, now, ttl_sec, backend, monkeypatch):
        f = Fernet(secret.encode("ascii"), backend=backend)
        current_time = calendar.timegm(iso8601.parse_date(now).utctimetuple())
        with pytest.raises(InvalidToken):
            f.decrypt_at_time(
                token.encode("ascii"),
                ttl=ttl_sec,
                current_time=current_time,
            )
        monkeypatch.setattr(time, "time", lambda: current_time)
        with pytest.raises(InvalidToken):
            f.decrypt(token.encode("ascii"), ttl=ttl_sec)

    def test_invalid_start_byte(self, backend):
        f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
        with pytest.raises(InvalidToken):
            f.decrypt(base64.urlsafe_b64encode(b"\x81"))

    def test_timestamp_too_short(self, backend):
        f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
        with pytest.raises(InvalidToken):
            f.decrypt(base64.urlsafe_b64encode(b"\x80abc"))

    def test_non_base64_token(self, backend):
        f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
        with pytest.raises(InvalidToken):
            f.decrypt(b"\x00")
        with pytest.raises(InvalidToken):
            f.decrypt("nonsensetoken")

    def test_invalid_types(self, backend):
        f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
        with pytest.raises(TypeError):
            f.encrypt("")  # type: ignore[arg-type]
        with pytest.raises(TypeError):
            f.decrypt(12345)  # type: ignore[arg-type]

    def test_timestamp_ignored_no_ttl(self, monkeypatch, backend):
        f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
        pt = b"encrypt me"
        token = f.encrypt(pt)
        monkeypatch.setattr(time, "time", pretend.raiser(ValueError))
        assert f.decrypt(token, ttl=None) == pt

    def test_ttl_required_in_decrypt_at_time(self, monkeypatch, backend):
        f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
        pt = b"encrypt me"
        token = f.encrypt(pt)
        with pytest.raises(ValueError):
            f.decrypt_at_time(
                token,
                ttl=None,  # type: ignore[arg-type]
                current_time=int(time.time()),
            )

    @pytest.mark.parametrize("message", [b"", b"Abc!", b"\x00\xFF\x00\x80"])
    def test_roundtrips(self, message, backend):
        f = Fernet(Fernet.generate_key(), backend=backend)
        assert f.decrypt(f.encrypt(message)) == message

    @pytest.mark.parametrize("key", [base64.urlsafe_b64encode(b"abc"), b"abc"])
    def test_bad_key(self, backend, key):
        with pytest.raises(ValueError):
            Fernet(key, backend=backend)

    def test_extract_timestamp(self, monkeypatch, backend):
        f = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
        current_time = 1526138327
        token = f.encrypt_at_time(b"encrypt me", current_time)
        assert f.extract_timestamp(token) == current_time
        assert f.extract_timestamp(token.decode("ascii")) == current_time
        with pytest.raises(InvalidToken):
            f.extract_timestamp(b"nonsensetoken")


@pytest.mark.supported(
    only_if=lambda backend: backend.cipher_supported(
        algorithms.AES(b"\x00" * 32), modes.CBC(b"\x00" * 16)
    ),
    skip_message="Does not support AES CBC",
)
class TestMultiFernet:
    def test_encrypt(self, backend):
        f1 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
        f2 = Fernet(base64.urlsafe_b64encode(b"\x01" * 32), backend=backend)
        f = MultiFernet([f1, f2])

        assert f1.decrypt(f.encrypt(b"abc")) == b"abc"

    def test_decrypt(self, backend):
        f1 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
        f2 = Fernet(base64.urlsafe_b64encode(b"\x01" * 32), backend=backend)
        f = MultiFernet([f1, f2])

        # token as bytes
        assert f.decrypt(f1.encrypt(b"abc")) == b"abc"
        assert f.decrypt(f2.encrypt(b"abc")) == b"abc"

        # token as str
        assert f.decrypt(f1.encrypt(b"abc").decode("ascii")) == b"abc"
        assert f.decrypt(f2.encrypt(b"abc").decode("ascii")) == b"abc"

        with pytest.raises(InvalidToken):
            f.decrypt(b"\x00" * 16)

    def test_decrypt_at_time(self, backend):
        f1 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
        f = MultiFernet([f1])
        pt = b"encrypt me"
        token = f.encrypt_at_time(pt, current_time=100)
        assert f.decrypt_at_time(token, ttl=1, current_time=100) == pt
        with pytest.raises(InvalidToken):
            f.decrypt_at_time(token, ttl=1, current_time=102)
        with pytest.raises(ValueError):
            f.decrypt_at_time(
                token, ttl=None, current_time=100  # type: ignore[arg-type]
            )

    def test_no_fernets(self, backend):
        with pytest.raises(ValueError):
            MultiFernet([])

    def test_non_iterable_argument(self, backend):
        with pytest.raises(TypeError):
            MultiFernet(None)  # type: ignore[arg-type]

    def test_rotate_bytes(self, backend):
        f1 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
        f2 = Fernet(base64.urlsafe_b64encode(b"\x01" * 32), backend=backend)

        mf1 = MultiFernet([f1])
        mf2 = MultiFernet([f2, f1])

        plaintext = b"abc"
        mf1_ciphertext = mf1.encrypt(plaintext)

        assert mf2.decrypt(mf1_ciphertext) == plaintext

        rotated = mf2.rotate(mf1_ciphertext)

        assert rotated != mf1_ciphertext
        assert mf2.decrypt(rotated) == plaintext

        with pytest.raises(InvalidToken):
            mf1.decrypt(rotated)

    def test_rotate_str(self, backend):
        f1 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
        f2 = Fernet(base64.urlsafe_b64encode(b"\x01" * 32), backend=backend)

        mf1 = MultiFernet([f1])
        mf2 = MultiFernet([f2, f1])

        plaintext = b"abc"
        mf1_ciphertext = mf1.encrypt(plaintext).decode("ascii")

        assert mf2.decrypt(mf1_ciphertext) == plaintext
        rotated = mf2.rotate(mf1_ciphertext).decode("ascii")

        assert rotated != mf1_ciphertext
        assert mf2.decrypt(rotated) == plaintext

        with pytest.raises(InvalidToken):
            mf1.decrypt(rotated)

    def test_rotate_preserves_timestamp(self, backend, monkeypatch):
        f1 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
        f2 = Fernet(base64.urlsafe_b64encode(b"\x01" * 32), backend=backend)

        mf1 = MultiFernet([f1])
        mf2 = MultiFernet([f2, f1])

        plaintext = b"abc"
        original_time = int(time.time()) - 5 * 60
        mf1_ciphertext = mf1.encrypt_at_time(plaintext, original_time)

        rotated_time, _ = Fernet._get_unverified_token_data(
            mf2.rotate(mf1_ciphertext)
        )

        assert int(time.time()) != rotated_time
        assert original_time == rotated_time

    def test_rotate_decrypt_no_shared_keys(self, backend):
        f1 = Fernet(base64.urlsafe_b64encode(b"\x00" * 32), backend=backend)
        f2 = Fernet(base64.urlsafe_b64encode(b"\x01" * 32), backend=backend)

        mf1 = MultiFernet([f1])
        mf2 = MultiFernet([f2])

        with pytest.raises(InvalidToken):
            mf2.rotate(mf1.encrypt(b"abc"))