#!/usr/bin/env/ python

"""
<Program Name>
  test_ecdsa_keys.py

<Author>
  Vladimir Diaz <vladimir.v.diaz@gmail.com>

<Started>
  November 23, 2016.

<Copyright>
  See LICENSE for licensing information.

<Purpose>
  Test cases for test_ecdsa_keys.py.
"""

import unittest

import securesystemslib.ecdsa_keys
import securesystemslib.exceptions
import securesystemslib.formats
import securesystemslib.rsa_keys

public, private = securesystemslib.ecdsa_keys.generate_public_and_private()
FORMAT_ERROR_MSG = (
    "securesystemslib.exceptions.FormatError raised.  Check object's format."
)


class TestECDSA_keys(
    unittest.TestCase
):  # pylint: disable=missing-class-docstring,invalid-name
    def setUp(self):
        pass

    def test_generate_public_and_private(self):
        (
            public,  # pylint: disable=redefined-outer-name
            private,  # pylint: disable=redefined-outer-name
        ) = securesystemslib.ecdsa_keys.generate_public_and_private()

        # Check format of 'public' and 'private'.
        self.assertEqual(
            True, securesystemslib.formats.PEMECDSA_SCHEMA.matches(public)
        )
        self.assertEqual(
            True, securesystemslib.formats.PEMECDSA_SCHEMA.matches(private)
        )

        # Test for invalid argument.
        self.assertRaises(
            securesystemslib.exceptions.FormatError,
            securesystemslib.ecdsa_keys.generate_public_and_private,
            "bad_algo",
        )

    def test_create_ecdsa_public_and_private_from_pem(self):
        global public  # pylint: disable=global-statement
        global private  # pylint: disable=global-statement

        # Check format of 'public' and 'private'.
        self.assertEqual(
            True, securesystemslib.formats.PEMECDSA_SCHEMA.matches(public)
        )
        self.assertEqual(
            True, securesystemslib.formats.PEMECDSA_SCHEMA.matches(private)
        )

        # Check for a valid private pem.
        (
            public,
            private,
        ) = securesystemslib.ecdsa_keys.create_ecdsa_public_and_private_from_pem(
            private
        )

        # Check for an invalid pem (non-private).
        self.assertRaises(
            securesystemslib.exceptions.CryptoError,
            securesystemslib.ecdsa_keys.create_ecdsa_public_and_private_from_pem,
            public,
        )

        # Test for invalid argument.
        self.assertRaises(
            securesystemslib.exceptions.FormatError,
            securesystemslib.ecdsa_keys.create_ecdsa_public_and_private_from_pem,
            123,
        )

    def test_create_signature(self):
        global public  # pylint: disable=global-variable-not-assigned
        global private  # pylint: disable=global-variable-not-assigned
        data = b"The quick brown fox jumps over the lazy dog"
        signature, method = securesystemslib.ecdsa_keys.create_signature(
            public, private, data
        )

        # Verify format of returned values.
        self.assertEqual(
            True,
            securesystemslib.formats.ECDSASIGNATURE_SCHEMA.matches(signature),
        )

        self.assertEqual(
            True, securesystemslib.formats.NAME_SCHEMA.matches(method)
        )
        self.assertEqual("ecdsa-sha2-nistp256", method)

        # Check for improperly formatted argument.
        self.assertRaises(
            securesystemslib.exceptions.FormatError,
            securesystemslib.ecdsa_keys.create_signature,
            123,
            private,
            data,
        )

        self.assertRaises(
            securesystemslib.exceptions.FormatError,
            securesystemslib.ecdsa_keys.create_signature,
            public,
            123,
            data,
        )

        # Check for invalid 'data'.
        self.assertRaises(
            securesystemslib.exceptions.CryptoError,
            securesystemslib.ecdsa_keys.create_signature,
            public,
            private,
            123,
        )

    def test_verify_signature(self):
        global public  # pylint: disable=global-variable-not-assigned
        global private  # pylint: disable=global-variable-not-assigned
        data = b"The quick brown fox jumps over the lazy dog"
        scheme = "ecdsa-sha2-nistp256"
        signature, scheme = securesystemslib.ecdsa_keys.create_signature(
            public, private, data, scheme
        )

        valid_signature = securesystemslib.ecdsa_keys.verify_signature(
            public, scheme, signature, data
        )
        self.assertEqual(True, valid_signature)

        # Generate an RSA key so that we can verify that non-ECDSA keys are
        # rejected.
        rsa_pem, _ = securesystemslib.rsa_keys.generate_rsa_public_and_private()

        # Verify that a non-ECDSA key (via the PEM argument) is rejected.
        self.assertRaises(
            securesystemslib.exceptions.FormatError,
            securesystemslib.ecdsa_keys.verify_signature,
            rsa_pem,
            scheme,
            signature,
            data,
        )

        # Check for improperly formatted arguments.
        self.assertRaises(
            securesystemslib.exceptions.FormatError,
            securesystemslib.ecdsa_keys.verify_signature,
            123,
            scheme,
            signature,
            data,
        )

        # Signature method improperly formatted.
        self.assertRaises(
            securesystemslib.exceptions.FormatError,
            securesystemslib.ecdsa_keys.verify_signature,
            public,
            123,
            signature,
            data,
        )

        # Invalid signature method.
        self.assertRaises(
            securesystemslib.exceptions.FormatError,
            securesystemslib.ecdsa_keys.verify_signature,
            public,
            "unsupported_scheme",
            signature,
            data,
        )

        # Signature not a string.
        self.assertRaises(
            securesystemslib.exceptions.FormatError,
            securesystemslib.ecdsa_keys.verify_signature,
            public,
            scheme,
            123,
            data,
        )

        # Invalid signature..
        self.assertRaises(
            securesystemslib.exceptions.FormatError,
            securesystemslib.ecdsa_keys.verify_signature,
            public,
            scheme,
            "bad_signature",
            data,
        )

        # Check for invalid signature and data.
        self.assertEqual(
            False,
            securesystemslib.ecdsa_keys.verify_signature(
                public, scheme, signature, b"123"
            ),
        )

        # Mismatched signature.
        bad_signature = b"a" * 64
        self.assertEqual(
            False,
            securesystemslib.ecdsa_keys.verify_signature(
                public, scheme, bad_signature, data
            ),
        )

        # Generated signature created with different data.
        new_signature, scheme = securesystemslib.ecdsa_keys.create_signature(
            public, private, b"mismatched data"
        )

        self.assertEqual(
            False,
            securesystemslib.ecdsa_keys.verify_signature(
                public, scheme, new_signature, data
            ),
        )


# Run the unit tests.
if __name__ == "__main__":
    unittest.main()