/*
 * Copyright (c) 2022, Ben Wiederhake <BenWiederhake.GitHub@gmx.de>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <AK/StringView.h>
#include <LibCrypto/ASN1/ASN1.h>
#include <LibTest/TestCase.h>

#define EXPECT_DATETIME(sv, y, mo, d, h, mi, s) \
    EXPECT_EQ(Crypto::ASN1::parse_utc_time(sv).value(), Core::DateTime::create(y, mo, d, h, mi, s))

TEST_CASE(test_utc_boring)
{
    // YYMMDDhhmm[ss]Z
    EXPECT_DATETIME("010101010101Z"sv, 2001, 1, 1, 1, 1, 1);
    EXPECT_DATETIME("010203040506Z"sv, 2001, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("020406081012Z"sv, 2002, 4, 6, 8, 10, 12);
    EXPECT_DATETIME("0204060810Z"sv, 2002, 4, 6, 8, 10, 0);
    EXPECT_DATETIME("220911220000Z"sv, 2022, 9, 11, 22, 0, 0);
}

TEST_CASE(test_utc_year_rollover)
{
    // YYMMDDhhmm[ss]Z
    EXPECT_DATETIME("000101010101Z"sv, 2000, 1, 1, 1, 1, 1);
    EXPECT_DATETIME("010101010101Z"sv, 2001, 1, 1, 1, 1, 1);
    EXPECT_DATETIME("020101010101Z"sv, 2002, 1, 1, 1, 1, 1);
    // ...
    EXPECT_DATETIME("480101010101Z"sv, 2048, 1, 1, 1, 1, 1);
    EXPECT_DATETIME("490101010101Z"sv, 2049, 1, 1, 1, 1, 1);
    // This Y2050-problem is hardcoded in the spec. Oh no.
    EXPECT_DATETIME("500101010101Z"sv, 1950, 1, 1, 1, 1, 1);
    EXPECT_DATETIME("510101010101Z"sv, 1951, 1, 1, 1, 1, 1);
    // ...
    EXPECT_DATETIME("970101010101Z"sv, 1997, 1, 1, 1, 1, 1);
    EXPECT_DATETIME("980101010101Z"sv, 1998, 1, 1, 1, 1, 1);
    EXPECT_DATETIME("990101010101Z"sv, 1999, 1, 1, 1, 1, 1);
}

TEST_CASE(test_utc_offset)
{
    // YYMMDDhhmm[ss](+|-)hhmm
    // We don't yet support storing the offset anywhere and instead just assume that the offset is just +0000.
    EXPECT_DATETIME("010101010101+0000"sv, 2001, 1, 1, 1, 1, 1);
    EXPECT_DATETIME("010203040506+0000"sv, 2001, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("020406081012+0000"sv, 2002, 4, 6, 8, 10, 12);
    EXPECT_DATETIME("0204060810+0000"sv, 2002, 4, 6, 8, 10, 0);
    EXPECT_DATETIME("220911220000+0000"sv, 2022, 9, 11, 22, 0, 0);
    // Designed to fail once we support offsets:
    EXPECT_DATETIME("220911220000+0600"sv, 2022, 9, 11, 22, 0, 0);
}

TEST_CASE(test_utc_missing_z)
{
    // YYMMDDhhmm[ss]
    // We don't actually need to parse this correctly; rejecting these inputs is fine.
    // This test just makes sure that we don't crash.
    (void)Crypto::ASN1::parse_utc_time("010101010101"sv);
    (void)Crypto::ASN1::parse_utc_time("010203040506"sv);
    (void)Crypto::ASN1::parse_utc_time("020406081012"sv);
    (void)Crypto::ASN1::parse_utc_time("0204060810"sv);
    (void)Crypto::ASN1::parse_utc_time("220911220000"sv);
}

#undef EXPECT_DATETIME
#define EXPECT_DATETIME(sv, y, mo, d, h, mi, s) \
    EXPECT_EQ(Crypto::ASN1::parse_generalized_time(sv).value(), Core::DateTime::create(y, mo, d, h, mi, s))

TEST_CASE(test_generalized_boring)
{
    // YYYYMMDDhh[mm[ss[.fff]]]
    EXPECT_DATETIME("20010101010101Z"sv, 2001, 1, 1, 1, 1, 1);
    EXPECT_DATETIME("20010203040506Z"sv, 2001, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("20020406081012Z"sv, 2002, 4, 6, 8, 10, 12);
    EXPECT_DATETIME("200204060810Z"sv, 2002, 4, 6, 8, 10, 0);
    EXPECT_DATETIME("2002040608Z"sv, 2002, 4, 6, 8, 0, 0);
    // TODO: We probably should not discard the milliseconds.
    EXPECT_DATETIME("20020406081012.567Z"sv, 2002, 4, 6, 8, 10, 12);
    EXPECT_DATETIME("20220911220000Z"sv, 2022, 9, 11, 22, 0, 0);
}

TEST_CASE(test_generalized_offset)
{
    // YYYYMMDDhh[mm[ss[.fff]]](+|-)hhmm
    // We don't yet support storing the offset anywhere and instead just assume that the offset is just +0000.
    EXPECT_DATETIME("20010101010101+0000"sv, 2001, 1, 1, 1, 1, 1);
    EXPECT_DATETIME("20010203040506+0000"sv, 2001, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("20020406081012+0000"sv, 2002, 4, 6, 8, 10, 12);
    EXPECT_DATETIME("200204060810+0000"sv, 2002, 4, 6, 8, 10, 0);
    EXPECT_DATETIME("2002040608+0000"sv, 2002, 4, 6, 8, 0, 0);
    // TODO: We probably should not discard the milliseconds.
    EXPECT_DATETIME("20020406081012.567+0000"sv, 2002, 4, 6, 8, 10, 12);
    EXPECT_DATETIME("20220911220000+0000"sv, 2022, 9, 11, 22, 0, 0);
    // Designed to fail once we support offsets:
    EXPECT_DATETIME("20220911220000+0600"sv, 2022, 9, 11, 22, 0, 0);
}

TEST_CASE(test_generalized_missing_z)
{
    // YYYYMMDDhh[mm[ss[.fff]]]
    EXPECT_DATETIME("20010101010101"sv, 2001, 1, 1, 1, 1, 1);
    EXPECT_DATETIME("20010203040506"sv, 2001, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("20020406081012"sv, 2002, 4, 6, 8, 10, 12);
    EXPECT_DATETIME("200204060810"sv, 2002, 4, 6, 8, 10, 0);
    EXPECT_DATETIME("2002040608"sv, 2002, 4, 6, 8, 0, 0);
    // TODO: We probably should not discard the milliseconds.
    EXPECT_DATETIME("20020406081012.567"sv, 2002, 4, 6, 8, 10, 12);
    EXPECT_DATETIME("20220911220000"sv, 2022, 9, 11, 22, 0, 0);
}

TEST_CASE(test_generalized_unusual_year)
{
    // Towards the positive
    EXPECT_DATETIME("20010203040506Z"sv, 2001, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("20110203040506Z"sv, 2011, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("21010203040506Z"sv, 2101, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("30010203040506Z"sv, 3001, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("40010203040506Z"sv, 4001, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("90010203040506Z"sv, 9001, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("99990203040506Z"sv, 9999, 2, 3, 4, 5, 6);

    // Towards zero
    EXPECT_DATETIME("20010203040506Z"sv, 2001, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("19990203040506Z"sv, 1999, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("19500203040506Z"sv, 1950, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("19010203040506Z"sv, 1901, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("18010203040506Z"sv, 1801, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("15010203040506Z"sv, 1501, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("10010203040506Z"sv, 1001, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("01010203040506Z"sv, 101, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("00110203040506Z"sv, 11, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("00010203040506Z"sv, 1, 2, 3, 4, 5, 6);
    EXPECT_DATETIME("00000203040506Z"sv, 0, 2, 3, 4, 5, 6);

    // Problematic dates
    EXPECT_DATETIME("20200229040506Z"sv, 2020, 2, 29, 4, 5, 6);
    EXPECT_DATETIME("20000229040506Z"sv, 2000, 2, 29, 4, 5, 6);
    EXPECT_DATETIME("24000229040506Z"sv, 2400, 2, 29, 4, 5, 6);
}

TEST_CASE(test_generalized_nonexistent_dates)
{
    // The following dates don't exist. I'm not sure what the "correct" result is,
    // but we need to make sure that we don't crash.
    (void)Crypto::ASN1::parse_generalized_time("20210229040506Z"sv); // Not a leap year (not divisible by 4)
    (void)Crypto::ASN1::parse_generalized_time("21000229040506Z"sv); // Not a leap year (divisible by 100)
    (void)Crypto::ASN1::parse_generalized_time("20220230040506Z"sv); // Never exists
    (void)Crypto::ASN1::parse_generalized_time("20220631040506Z"sv); // Never exists
    (void)Crypto::ASN1::parse_generalized_time("20220732040506Z"sv); // Never exists

    // https://www.timeanddate.com/calendar/julian-gregorian-switch.html
    (void)Crypto::ASN1::parse_generalized_time("15821214040506Z"sv); // Gregorian switch; France
    (void)Crypto::ASN1::parse_generalized_time("15821011040506Z"sv); // Gregorian switch; Italy, Poland, Portugal, Spain
    (void)Crypto::ASN1::parse_generalized_time("15830105040506Z"sv); // Gregorian switch; Germany (Catholic)
    (void)Crypto::ASN1::parse_generalized_time("15831011040506Z"sv); // Gregorian switch; Austria
    (void)Crypto::ASN1::parse_generalized_time("15871026040506Z"sv); // Gregorian switch; Hungary
    (void)Crypto::ASN1::parse_generalized_time("16100826040506Z"sv); // Gregorian switch; Germany (old Prussia)
    (void)Crypto::ASN1::parse_generalized_time("17000223040506Z"sv); // Gregorian switch; Germany (Protestant)
    (void)Crypto::ASN1::parse_generalized_time("17520908040506Z"sv); // Gregorian switch; US, Canada, UK
    (void)Crypto::ASN1::parse_generalized_time("18711225040506Z"sv); // Gregorian switch; Japan
    (void)Crypto::ASN1::parse_generalized_time("19160407040506Z"sv); // Gregorian switch; Bulgaria
    (void)Crypto::ASN1::parse_generalized_time("19180207040506Z"sv); // Gregorian switch; Estonia, Russia
    (void)Crypto::ASN1::parse_generalized_time("19230222040506Z"sv); // Gregorian switch; Greece
    (void)Crypto::ASN1::parse_generalized_time("19261224040506Z"sv); // Gregorian switch; Turkey
}