// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <pretty/sizes.h>
#include <unittest/unittest.h>

typedef struct {
    const size_t input;
    const char unit;
    const char* expected_output;
} format_size_test_case_t;

#define KILO (1024ULL)
#define MEGA (KILO * 1024)
#define GIGA (MEGA * 1024)
#define TERA (GIGA * 1024)
#define PETA (TERA * 1024)
#define EXA (PETA * 1024)

static const format_size_test_case_t format_size_test_cases[] = {
// Declare a test case that uses a unit of 0,
// picking a natural unit for the size.
#define TC0(i, o) \
    { .input = i, .unit = 0, .expected_output = o }

    // Whole multiples don't print decimals,
    // and always round up to their largest unit.
    TC0(0, "0B"),
    TC0(1, "1B"),

    // Favor the largest unit when it loses no precision
    // (e.g., "1k" not "1024B").
    // Larger values may still use a smaller unit
    // (e.g., "1k" + 1 == "1025B") to preserve precision.
    TC0(KILO - 1, "1023B"),
    TC0(KILO, "1k"),
    TC0(KILO + 1, "1025B"),
    TC0(KILO * 9, "9k"),
    TC0(KILO * 9 + 1, "9217B"),
    TC0(KILO * 10, "10k"),

    // Same demonstration for the next unit.
    TC0(MEGA - KILO, "1023k"),
    TC0(MEGA, "1M"),
    TC0(MEGA + KILO, "1025k"),
    TC0(MEGA * 9, "9M"),
    TC0(MEGA * 9 + KILO, "9217k"),
    TC0(MEGA * 10, "10M"),

    // Sanity checks for remaining units.
    TC0(MEGA, "1M"),
    TC0(GIGA, "1G"),
    TC0(TERA, "1T"),
    TC0(PETA, "1P"),
    TC0(EXA, "1E"),

    // Non-whole multiples print decimals, and favor more whole digits
    // (e.g., "1024.0k" not "1.0M") to retain precision.
    TC0(MEGA - 1, "1024.0k"),
    TC0(MEGA + MEGA / 3, "1365.3k"), // Only one decimal place is ever shown.
    TC0(GIGA - 1, "1024.0M"),
    TC0(TERA - 1, "1024.0G"),
    TC0(PETA - 1, "1024.0T"),
    TC0(EXA - 1, "1024.0P"),
    TC0(UINT64_MAX, "16.0E"),

    // Never show more than four whole digits,
    // to make the values easier to eyeball.
    TC0(9999, "9999B"),
    TC0(10000, "9.8k"),
    TC0(KILO * 9999, "9999k"),
    TC0(KILO * 9999 + 1, "9999.0k"),
    TC0(KILO * 10000, "9.8M"),

// Declare a test case fixed to the specified unit.
#define TCF(i, u, o) \
    { .input = i, .unit = u, .expected_output = o }

    // When fixed, we can see a lot more digits.
    TCF(UINT64_MAX, 'B', "18446744073709551615B"),
    TCF(UINT64_MAX, 'k', "18014398509481984.0k"),
    TCF(UINT64_MAX, 'M', "17592186044416.0M"),
    TCF(UINT64_MAX, 'G', "17179869184.0G"),
    TCF(UINT64_MAX, 'T', "16777216.0T"),
    TCF(UINT64_MAX, 'P', "16384.0P"),
    TCF(UINT64_MAX, 'E', "16.0E"),

    // Smaller than natural fixed unit.
    TCF(GIGA, 'k', "1048576k"),

    // Larger than natural fixed unit.
    TCF(MEGA / 10, 'M', "0.1M"),

    // Unknown units fall back to natural, but add a '?' prefix.
    TCF(GIGA, 'q', "?1G"),
    TCF(KILO, 'q', "?1k"),
    TCF(GIGA + 1, '#', "?1.0G"),
    TCF(KILO + 1, '#', "?1025B"),
};

bool format_size_fixed_test(void) {
    BEGIN_TEST;
    char str[MAX_FORMAT_SIZE_LEN];
    char msg[128];
    for (unsigned int i = 0; i < countof(format_size_test_cases); i++) {
        const format_size_test_case_t* tc = format_size_test_cases + i;
        memset(str, 0, sizeof(str));
        char* ret = format_size_fixed(str, sizeof(str), tc->input, tc->unit);
        snprintf(msg, sizeof(msg), "format_size_fixed(bytes=%zd, unit=%c)",
                 tc->input, tc->unit == 0 ? '0' : tc->unit);
        EXPECT_STR_EQ(tc->expected_output, str, /* len */ 128, msg);
        // Should always return the input pointer.
        EXPECT_EQ(&(str[0]), ret, msg);
    }
    END_TEST;
}

bool format_size_short_buf_truncates(void) {
    BEGIN_TEST;
    // Widest possible output: four whole digits + decimal.
    static const size_t input = 1023 * 1024 + 1;
    static const char expected_output[] = "1023.0k";

    char buf[sizeof(expected_output) * 2];
    char msg[128];
    for (size_t str_size = 0; str_size <= sizeof(expected_output);
         str_size++) {
        memset(buf, 0x55, sizeof(buf));
        char* ret = format_size(buf, str_size, input);

        snprintf(msg, sizeof(msg),
                 "format_size(str_size=%zd, bytes=%zd)", str_size, input);
        EXPECT_EQ(&(buf[0]), ret, msg);
        if (str_size > 2) {
            EXPECT_BYTES_EQ(
                (uint8_t*)expected_output, (uint8_t*)buf, str_size - 1, msg);
        }
        if (str_size > 1) {
            EXPECT_EQ(buf[str_size - 1], '\0', msg);
        }
        EXPECT_EQ(buf[str_size], 0x55, msg);
    }
    END_TEST;
}

// Tests the path where we add a prefix '?' to make sure we don't
// overrun the buffer or return a non-null-terminated result.
bool format_size_bad_unit_short_buf_truncates(void) {
    BEGIN_TEST;

    char buf[MAX_FORMAT_SIZE_LEN];

    // Size zero should not touch the buffer.
    memset(buf, 0x55, sizeof(buf));
    format_size_fixed(buf, 0, GIGA, 'q');
    EXPECT_EQ(buf[0], 0x55, "");

    // Size 1 should only null out the first byte.
    memset(buf, 0x55, sizeof(buf));
    format_size_fixed(buf, 1, GIGA, 'q');
    EXPECT_EQ(buf[0], '\0', "");
    EXPECT_EQ(buf[1], 0x55, "");

    // Size 2 should just be the warning '?'.
    memset(buf, 0x55, sizeof(buf));
    format_size_fixed(buf, 2, GIGA, 'q');
    EXPECT_EQ(buf[0], '?', "");
    EXPECT_EQ(buf[1], '\0', "");
    EXPECT_EQ(buf[2], 0x55, "");

    // Then just the number without units.
    memset(buf, 0x55, sizeof(buf));
    format_size_fixed(buf, 3, GIGA, 'q');
    EXPECT_EQ(buf[0], '?', "");
    EXPECT_EQ(buf[1], '1', "");
    EXPECT_EQ(buf[2], '\0', "");
    EXPECT_EQ(buf[3], 0x55, "");

    // Then the whole thing.
    memset(buf, 0x55, sizeof(buf));
    format_size_fixed(buf, 4, GIGA, 'q');
    EXPECT_EQ(buf[0], '?', "");
    EXPECT_EQ(buf[1], '1', "");
    EXPECT_EQ(buf[2], 'G', "");
    EXPECT_EQ(buf[3], '\0', "");
    EXPECT_EQ(buf[4], 0x55, "");

    END_TEST;
}

bool format_size_empty_str_succeeds(void) {
    BEGIN_TEST;
    static const size_t input = 1023 * 1024 + 1;

    char c = 0x55;
    char* ret = format_size(&c, 0, input);
    EXPECT_EQ(&c, ret, "");
    EXPECT_EQ(0x55, c, "");
    END_TEST;
}

bool format_size_empty_null_str_succeeds(void) {
    BEGIN_TEST;
    static const size_t input = 1023 * 1024 + 1;

    char* ret = format_size(NULL, 0, input);
    EXPECT_EQ(NULL, ret, "");
    END_TEST;
}

BEGIN_TEST_CASE(pretty_tests)
RUN_TEST(format_size_fixed_test)
RUN_TEST(format_size_short_buf_truncates)
RUN_TEST(format_size_bad_unit_short_buf_truncates)
RUN_TEST(format_size_empty_str_succeeds)
RUN_TEST(format_size_empty_null_str_succeeds)
END_TEST_CASE(pretty_tests)

int main(int argc, char** argv) {
    return unittest_run_all_tests(argc, argv) ? 0 : -1;
}