// This file is part of OpenCV project.
// It is subject to the license terms in the LICENSE file found in the top-level directory
// of this distribution and at http://opencv.org/license.html

// Regression tests for the Sun Raster decoder (grfmt_sunras.cpp).
// These tests guard against:
//   - UBSan "load of invalid enum value" in SunRasterDecoder::readHeader()
//     (see https://github.com/opencv/opencv/issues/29150)
//   - Out-of-range SunRasType / SunRasMapType values causing UB via unchecked C-cast

#include "test_precomp.hpp"

#include <fstream>
#include <iterator>
#include <vector>

namespace opencv_test { namespace {

// ---------------------------------------------------------------------------
// Helper: build a minimal Sun Raster byte buffer with caller-supplied fields.
// Sun Raster header layout (all fields big-endian, 32-bit):
//   [0]  magic     = 0x59a66a95
//   [4]  width
//   [8]  height
//   [12] depth     (bits-per-pixel)
//   [16] length    (image data length, may be 0 for RAS_OLD)
//   [20] ras_type  (SunRasType)
//   [24] maptype   (SunRasMapType)
//   [28] maplength
// ---------------------------------------------------------------------------
static std::vector<uint8_t> makeSunRasHeader(
    uint32_t width, uint32_t height, uint32_t depth,
    uint32_t length, uint32_t ras_type, uint32_t maptype, uint32_t maplength)
{
    std::vector<uint8_t> buf(32);
    auto put32 = [&](size_t off, uint32_t v) {
        buf[off+0] = (v >> 24) & 0xff;
        buf[off+1] = (v >> 16) & 0xff;
        buf[off+2] = (v >>  8) & 0xff;
        buf[off+3] = (v      ) & 0xff;
    };
    put32( 0, 0x59a66a95u); // magic
    put32( 4, width);
    put32( 8, height);
    put32(12, depth);
    put32(16, length);
    put32(20, ras_type);
    put32(24, maptype);
    put32(28, maplength);
    return buf;
}

// ---------------------------------------------------------------------------
// Crash / UBSan regression — issue #29150
// Feeding an invalid maptype value (34077 / 0x851d) must NOT trigger UB;
// imdecode must return an empty Mat gracefully.
// ---------------------------------------------------------------------------
TEST(Imgcodecs_SunRaster, invalid_maptype_returns_empty_29150)
{
    // Crafted header from the original bug report:
    //   magic=0x59a66a95, width=0x10101, height=0x10000, depth=1, length=0x1000000
    //   ras_type=0 (RAS_OLD, valid), maptype=0x851d (34077, INVALID)
    const std::vector<uint8_t> image_data = {
        0x59,0xa6,0x6a,0x95, 0x01,0x01,0x00,0x00,
        0x00,0x01,0x00,0x00, 0x00,0x00,0x00,0x01,
        0x01,0x00,0x00,0x00, 0x00,0x00,0x00,0x00,
        0x00,0x00,0x85,0x1d, 0xae,0x5b,0x8d,0xd5,
        0x9c,0x25,0x22,0x41, 0x51,0x92,0x13,0x14,0x33
    };

    cv::Mat result;
    ASSERT_NO_THROW(result = cv::imdecode(image_data, cv::IMREAD_REDUCED_GRAYSCALE_2));
    EXPECT_TRUE(result.empty()) << "imdecode must return empty Mat for invalid maptype";
}

// Invalid ras_type (value well outside [0,3]) must be rejected cleanly.
TEST(Imgcodecs_SunRaster, invalid_rastype_returns_empty)
{
    auto buf = makeSunRasHeader(/*w*/8, /*h*/8, /*depth*/8,
                                /*len*/0, /*ras_type*/0xFFFF, /*maptype*/0, /*mapllen*/0);
    cv::Mat result;
    ASSERT_NO_THROW(result = cv::imdecode(buf, cv::IMREAD_GRAYSCALE));
    EXPECT_TRUE(result.empty()) << "imdecode must return empty Mat for invalid ras_type";
}

// maptype = 2 is outside [0,1] (only RMT_NONE=0, RMT_EQUAL_RGB=1 are defined).
TEST(Imgcodecs_SunRaster, maptype_2_returns_empty)
{
    auto buf = makeSunRasHeader(8, 8, 8, 0, /*ras_type*/0, /*maptype*/2, 0);
    cv::Mat result;
    ASSERT_NO_THROW(result = cv::imdecode(buf, cv::IMREAD_GRAYSCALE));
    EXPECT_TRUE(result.empty()) << "imdecode must return empty Mat for maptype=2";
}

// maptype = UINT32_MAX is also invalid.
TEST(Imgcodecs_SunRaster, maptype_max_returns_empty)
{
    auto buf = makeSunRasHeader(8, 8, 8, 0, 0, 0xFFFFFFFFu, 0);
    cv::Mat result;
    ASSERT_NO_THROW(result = cv::imdecode(buf, cv::IMREAD_GRAYSCALE));
    EXPECT_TRUE(result.empty()) << "imdecode must return empty Mat for maptype=UINT_MAX";
}

// A truncated buffer (shorter than the 32-byte header) must not crash.
TEST(Imgcodecs_SunRaster, truncated_header_returns_empty)
{
    // Only 16 bytes — header read will run out of data.
    const std::vector<uint8_t> buf = {
        0x59,0xa6,0x6a,0x95, 0x00,0x00,0x00,0x08,
        0x00,0x00,0x00,0x08, 0x00,0x00,0x00,0x08
    };
    cv::Mat result;
    ASSERT_NO_THROW(result = cv::imdecode(buf, cv::IMREAD_GRAYSCALE));
    EXPECT_TRUE(result.empty()) << "imdecode must return empty Mat for truncated header";
}

// ---------------------------------------------------------------------------
// Sanity: a well-formed 8-bpp grayscale Sun Raster (RMT_NONE) still decodes.
// We build the full header + pixel data manually so the test has no file I/O.
// ---------------------------------------------------------------------------
TEST(Imgcodecs_SunRaster, valid_8bpp_grayscale_decodes)
{
    const int W = 4, H = 4;
    // RAS_OLD(0), maptype=RMT_NONE(0), maplength=0
    auto buf = makeSunRasHeader(W, H, 8, W*H, 0, 0, 0);

    // Sun Raster rows are padded to 16-bit boundary.
    // W=4: row_bytes = 4 (already even), no padding needed.
    for (int i = 0; i < W * H; ++i)
        buf.push_back(static_cast<uint8_t>(i * 16)); // arbitrary gray values

    cv::Mat result;
    ASSERT_NO_THROW(result = cv::imdecode(buf, cv::IMREAD_GRAYSCALE));
    EXPECT_FALSE(result.empty()) << "imdecode must succeed for a valid 8-bpp Sun Raster";
    EXPECT_EQ(result.cols, W);
    EXPECT_EQ(result.rows, H);
    EXPECT_EQ(result.type(), CV_8UC1);
}

TEST(Imgcodecs_SunRaster, byte_encoded_8bpp_decodes)
{
    // Generated with Netpbm's pnmtorast -rle.
    const String filename = findDataFile("readwrite/sunraster/byte_encoded_8bpp.ras");
    uint8_t expected_data[][16] = {
        { 0x11, 0x80, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44,
          0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44, 0x44 },
        { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
          0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
        { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
          0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff },
        { 0x20, 0x20, 0x40, 0x40, 0x60, 0x60, 0x80, 0x80,
          0xa0, 0xa0, 0xc0, 0xc0, 0xe0, 0xe0, 0xff, 0xff },
        { 0x33, 0x33, 0x33, 0x33, 0x33, 0x33, 0x33, 0x33,
          0x33, 0x33, 0x33, 0x33, 0x33, 0x33, 0x33, 0x33 },
        { 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66,
          0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66 },
        { 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
          0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99 },
        { 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc,
          0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc }
    };
    const cv::Mat expected(8, 16, CV_8UC1, expected_data);

    cv::Mat result;
    ASSERT_NO_THROW(result = cv::imread(filename, cv::IMREAD_GRAYSCALE));
    ASSERT_FALSE(result.empty());
    ASSERT_EQ(expected.size(), result.size());
    ASSERT_EQ(expected.type(), result.type());
    EXPECT_EQ(0, cv::norm(expected, result, cv::NORM_INF));
}

TEST(Imgcodecs_SunRaster, truncated_byte_encoded_8bpp_returns_empty)
{
    const String filename = findDataFile("readwrite/sunraster/byte_encoded_8bpp.ras");
    std::ifstream stream(filename.c_str(), std::ios::binary);
    ASSERT_TRUE(stream.is_open());
    std::vector<uint8_t> buf((std::istreambuf_iterator<char>(stream)),
                             std::istreambuf_iterator<char>());
    const size_t incompleteRleSize = 32 + 3 * 256 + 2;
    ASSERT_GT(buf.size(), incompleteRleSize);
    buf.resize(incompleteRleSize); // Keep an incomplete RLE escape after the color map.

    cv::Mat result;
    ASSERT_NO_THROW(result = cv::imdecode(buf, cv::IMREAD_GRAYSCALE));
    EXPECT_TRUE(result.empty());
}

typedef tuple<string, int> SunRasterColorParams;
typedef testing::TestWithParam<SunRasterColorParams> Imgcodecs_SunRaster_Color;

TEST_P(Imgcodecs_SunRaster_Color, decodes)
{
    const String filename = findDataFile(get<0>(GetParam()));
    const int flags = get<1>(GetParam());

    uint8_t bgr_data[] = {
        30, 20, 10, 60, 50, 40, 0, 0, 255, 0, 255, 0,
        255, 0, 0, 0, 255, 255, 255, 0, 255, 255, 255, 0
    };
    uint8_t rgb_data[] = {
        10, 20, 30, 40, 50, 60, 255, 0, 0, 0, 255, 0,
        0, 0, 255, 255, 255, 0, 255, 0, 255, 0, 255, 255
    };
    uint8_t gray_data[] = { 18, 48, 76, 150, 29, 226, 105, 179 };

    cv::Mat expected;
    if( flags == cv::IMREAD_COLOR )
        expected = cv::Mat(2, 4, CV_8UC3, bgr_data);
    else if( flags == cv::IMREAD_COLOR_RGB )
        expected = cv::Mat(2, 4, CV_8UC3, rgb_data);
    else
        expected = cv::Mat(2, 4, CV_8UC1, gray_data);

    cv::Mat result;
    ASSERT_NO_THROW(result = cv::imread(filename, flags));
    ASSERT_FALSE(result.empty());
    ASSERT_EQ(expected.size(), result.size());
    ASSERT_EQ(expected.type(), result.type());
    EXPECT_EQ(0, cv::norm(expected, result, cv::NORM_INF));
}

// Generated with ImageMagick's SUN encoder.
INSTANTIATE_TEST_CASE_P(RgbFormat, Imgcodecs_SunRaster_Color,
                        testing::Combine(
                            testing::Values(
                                "readwrite/sunraster/rgb_format_24bpp.ras",
                                "readwrite/sunraster/rgb_format_32bpp.ras"),
                            testing::Values(
                                cv::IMREAD_COLOR,
                                cv::IMREAD_COLOR_RGB,
                                cv::IMREAD_GRAYSCALE)));

}} // namespace opencv_test