// Vita3K emulator project
// Copyright (C) 2026 Vita3K team
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

#include <gxm/functions.h>
#include <gxm/types.h>
#include <renderer/commands.h>
#include <renderer/driver_functions.h>
#include <renderer/functions.h>
#include <renderer/state.h>
#include <renderer/types.h>
#include <util/log.h>
#include <util/tracy.h>

#include <renderer/vulkan/state.h>

// keywords.h must be after tracy.h for msvc compiler
#include <util/keywords.h>

extern "C" {
#include <libswscale/swscale.h>
}

namespace renderer {

template <typename T, SceGxmTransferColorKeyMode mode, SceGxmTransferType src_type, SceGxmTransferType dst_type>
static void perform_transfer_copy_impl(MemState &mem, const SceGxmTransferImage &src, const SceGxmTransferImage &dst, uint32_t key_value, uint32_t key_mask) {
    T *__restrict__ src_ptr = src.address.cast<T>().get(mem);
    T *__restrict__ dst_ptr = dst.address.cast<T>().get(mem);

    auto compute_offset = [&](uint32_t dx, uint32_t dy, const SceGxmTransferImage &img, SceGxmTransferType type) -> int32_t {
        const int32_t stride_pixel = img.stride / sizeof(T);
        if (type == SCE_GXM_TRANSFER_LINEAR) {
            return dy * stride_pixel + dx;
        } else if (type == SCE_GXM_TRANSFER_TILED) {
            // tiles are 32x32, you have the offset within the tile then the offset of the tile
            const uint32_t texel_offset_in_tile = ((dy % 32) * 32) + (dx % 32);
            const int32_t tile_address = (stride_pixel / 32) * (dy / 32) + (dx / 32);

            return tile_address * 1024 + texel_offset_in_tile;
        } else {
            return texture::encode_morton(dx, dy, img.width, img.height);
        }
    };

    for (uint32_t dx = 0; dx < src.width; dx++) {
        for (uint32_t dy = 0; dy < src.height; dy++) {
            // compute offset depending on the texture type used
            // the function compute_offset gets inlined
            uint32_t src_offset = compute_offset(src.x + dx, src.y + dy, src, src_type);
            uint32_t dst_offset = compute_offset(dst.x + dx, dst.y + dy, dst, dst_type);

            T value = src_ptr[src_offset];
            if constexpr (mode == SCE_GXM_TRANSFER_COLORKEY_PASS) {
                if ((value & key_mask) != key_value)
                    continue;
            } else if constexpr (mode == SCE_GXM_TRANSFER_COLORKEY_REJECT) {
                if ((value & key_mask) == key_value)
                    continue;
            }

            dst_ptr[dst_offset] = value;
        }
    }
}

template <typename T, SceGxmTransferColorKeyMode mode, SceGxmTransferType src_type>
static void perform_transfer_copy_dst_type(MemState &mem, const SceGxmTransferImage &src, const SceGxmTransferImage &dst, SceGxmTransferType dst_type, uint32_t key_value, uint32_t key_mask) {
    switch (dst_type) {
    case SCE_GXM_TRANSFER_LINEAR:
        perform_transfer_copy_impl<T, mode, src_type, SCE_GXM_TRANSFER_LINEAR>(mem, src, dst, key_value, key_mask);
        break;
    case SCE_GXM_TRANSFER_SWIZZLED:
        perform_transfer_copy_impl<T, mode, src_type, SCE_GXM_TRANSFER_SWIZZLED>(mem, src, dst, key_value, key_mask);
        break;
    case SCE_GXM_TRANSFER_TILED:
        perform_transfer_copy_impl<T, mode, src_type, SCE_GXM_TRANSFER_TILED>(mem, src, dst, key_value, key_mask);
        break;
    default:
        LOG_ERROR("Unknown transfer key mode {}", fmt::underlying(mode));
        break;
    }
}

template <typename T, SceGxmTransferColorKeyMode mode>
static void perform_transfer_copy_src_type(MemState &mem, const SceGxmTransferImage &src, const SceGxmTransferImage &dst, SceGxmTransferType src_type, SceGxmTransferType dst_type, uint32_t key_value, uint32_t key_mask) {
    switch (src_type) {
    case SCE_GXM_TRANSFER_LINEAR:
        perform_transfer_copy_dst_type<T, mode, SCE_GXM_TRANSFER_LINEAR>(mem, src, dst, dst_type, key_value, key_mask);
        break;
    case SCE_GXM_TRANSFER_SWIZZLED:
        perform_transfer_copy_dst_type<T, mode, SCE_GXM_TRANSFER_SWIZZLED>(mem, src, dst, dst_type, key_value, key_mask);
        break;
    case SCE_GXM_TRANSFER_TILED:
        perform_transfer_copy_dst_type<T, mode, SCE_GXM_TRANSFER_TILED>(mem, src, dst, dst_type, key_value, key_mask);
        break;
    default:
        LOG_ERROR("Unknown transfer key mode {}", fmt::underlying(mode));
        break;
    }
}

template <typename T>
static void perform_transfer_copy_mode(MemState &mem, const SceGxmTransferImage &src, const SceGxmTransferImage &dst, SceGxmTransferType src_type, SceGxmTransferType dst_type, uint32_t key_value, uint32_t key_mask, SceGxmTransferColorKeyMode mode) {
    switch (mode) {
    case SCE_GXM_TRANSFER_COLORKEY_NONE:
        perform_transfer_copy_src_type<T, SCE_GXM_TRANSFER_COLORKEY_NONE>(mem, src, dst, src_type, dst_type, key_value, key_mask);
        break;
    case SCE_GXM_TRANSFER_COLORKEY_PASS:
        perform_transfer_copy_src_type<T, SCE_GXM_TRANSFER_COLORKEY_PASS>(mem, src, dst, src_type, dst_type, key_value, key_mask);
        break;
    case SCE_GXM_TRANSFER_COLORKEY_REJECT:
        perform_transfer_copy_src_type<T, SCE_GXM_TRANSFER_COLORKEY_REJECT>(mem, src, dst, src_type, dst_type, key_value, key_mask);
        break;
    default:
        LOG_ERROR("Unknown transfer key mode {}", fmt::underlying(mode));
        break;
    }
}

COMMAND(handle_transfer_copy) {
    TRACY_FUNC_COMMANDS(handle_transfer_copy);
    const uint32_t colorKeyValue = helper.pop<uint32_t>();
    const uint32_t colorKeyMask = helper.pop<uint32_t>();
    SceGxmTransferColorKeyMode colorKeyMode = helper.pop<SceGxmTransferColorKeyMode>();
    const SceGxmTransferImage *images = helper.pop<SceGxmTransferImage *>();
    const SceGxmTransferFormat src_fmt = images[0].format;
    const SceGxmTransferFormat dst_fmt = images[1].format;
    SceGxmTransferType src_type = helper.pop<SceGxmTransferType>();
    SceGxmTransferType dst_type = helper.pop<SceGxmTransferType>();

    if (src_fmt != dst_fmt) {
        LOG_ERROR_ONCE("Unhandled format conversion from 0x{:0X} to 0x{:0X}", fmt::underlying(src_fmt), fmt::underlying(dst_fmt));
        delete[] images;
        return;
    }

    if (colorKeyMode != SCE_GXM_TRANSFER_COLORKEY_NONE && src_fmt != SCE_GXM_TRANSFER_FORMAT_U8U8U8U8_ABGR) {
        LOG_ERROR_ONCE("Transfer copy with non-zero key mask not handled for format 0x{:0X}", fmt::underlying(src_fmt));
    }

    vulkan::CallbackRequestFunction copy_operation = [=, &mem]() {
        const SceGxmTransferImage &src = images[0];
        const SceGxmTransferImage &dst = images[1];

        // Get bits per pixel of the image
        const uint32_t bpp = gxm::get_bits_per_pixel(src.format);

        // use a specialized function for each type (more optimized)
        switch (bpp) {
        case 8:
            perform_transfer_copy_src_type<uint8_t, SCE_GXM_TRANSFER_COLORKEY_NONE>(mem, src, dst, src_type, dst_type, colorKeyValue, colorKeyMask);
            break;
        case 16:
            perform_transfer_copy_src_type<uint16_t, SCE_GXM_TRANSFER_COLORKEY_NONE>(mem, src, dst, src_type, dst_type, colorKeyValue, colorKeyMask);
            break;
        case 24:
            perform_transfer_copy_src_type<std::array<uint8_t, 3>, SCE_GXM_TRANSFER_COLORKEY_NONE>(mem, src, dst, src_type, dst_type, colorKeyValue, colorKeyMask);
            break;
        case 32:
            perform_transfer_copy_mode<uint32_t>(mem, src, dst, src_type, dst_type, colorKeyValue, colorKeyMask, colorKeyMode);
            break;
        case 64:
            perform_transfer_copy_src_type<uint64_t, SCE_GXM_TRANSFER_COLORKEY_NONE>(mem, src, dst, src_type, dst_type, colorKeyValue, colorKeyMask);
            break;
        case 128:
            perform_transfer_copy_src_type<std::array<uint64_t, 2>, SCE_GXM_TRANSFER_COLORKEY_NONE>(mem, src, dst, src_type, dst_type, colorKeyValue, colorKeyMask);
            break;
        }

        delete[] images;
    };

    if (renderer.current_backend == Backend::Vulkan && renderer.features.enable_memory_mapping && !renderer.disable_surface_sync) {
        if (dynamic_cast<vulkan::VKState &>(renderer).surface_cache.check_for_surface(mem, images[0].address.address(), copy_operation, images[1].address.address()))
            // let the vulkan surface cache handle it
            return;
    }

    copy_operation();
}

COMMAND(handle_transfer_downscale) {
    TRACY_FUNC_COMMANDS(handle_transfer_downscale);
    SceGxmTransferImage *src = helper.pop<SceGxmTransferImage *>();
    SceGxmTransferImage *dst = helper.pop<SceGxmTransferImage *>();

    if (src->format != dst->format) {
        LOG_ERROR_ONCE("Unhandled format conversion from 0x{:0X} to 0x{:0X}", fmt::underlying(src->format), fmt::underlying(dst->format));
        return;
    }

    // adjust the x/y value
    const uint32_t pixel_bytes = gxm::get_bits_per_pixel(src->format) / 8;
    src->address = (src->address.cast<uint8_t>() + src->y * src->stride + src->x * pixel_bytes).cast<void>();
    dst->address = (dst->address.cast<uint8_t>() + dst->y * dst->stride + dst->x * pixel_bytes).cast<void>();

    // only rgb formats are supported by the PS Vita for downscaling
    vulkan::CallbackRequestFunction downscale_operation = [&mem, src, dst]() {
        AVPixelFormat pixel_fmt = AV_PIX_FMT_NONE;
        switch (src->format) {
        case SCE_GXM_TRANSFER_FORMAT_U5U6U5_BGR:
            pixel_fmt = AV_PIX_FMT_RGB565LE;
            break;
        case SCE_GXM_TRANSFER_FORMAT_U8U8U8_BGR:
            pixel_fmt = AV_PIX_FMT_RGB24;
            break;
        case SCE_GXM_TRANSFER_FORMAT_U8U8U8U8_ABGR:
            pixel_fmt = AV_PIX_FMT_RGBA;
            break;
        default:
            break;
        }

        uint8_t *src_ptr = src->address.cast<uint8_t>().get(mem);
        uint8_t *dst_ptr = dst->address.cast<uint8_t>().get(mem);

        if (pixel_fmt != AV_PIX_FMT_NONE && src->stride > 0 && dst->stride > 0) {
            // use ffmpeg with the avg filter
            SwsContext *ctx = sws_getContext(src->width, src->height, pixel_fmt, dst->width, dst->height, pixel_fmt, SWS_AREA, nullptr, nullptr, nullptr);
            if (ctx == nullptr) {
                LOG_ERROR("Failed to get ffmpeg context for format 0x{:0X}", fmt::underlying(src->format));
            } else {
                sws_scale(ctx, &src_ptr, &src->stride, 0, src->height, &dst_ptr, &dst->stride);
                sws_freeContext(ctx);
            }

        } else {
            // fallback, not (entirely) supported by ffmpeg
            // slow and not entirely accurate (nearest instead of average) fallback

            auto perform_downscale = [&]<typename T>(T type) {
                for (size_t y = 0; y < dst->height; y++) {
                    // stride is in bytes
                    T *src_line = reinterpret_cast<T *>(src_ptr + (size_t)src->stride * y * 2);
                    T *dst_line = reinterpret_cast<T *>(dst_ptr + (size_t)dst->stride * y);
                    for (size_t x = 0; x < dst->width; x++) {
                        dst_line[x] = src_line[2 * x];
                    }
                }
            };
            switch (gxm::get_bits_per_pixel(src->format)) {
            case 8:
                perform_downscale(uint8_t());
                break;
            case 16:
                perform_downscale(uint16_t());
                break;
            case 24:
                perform_downscale(std::array<uint8_t, 3>());
                break;
            case 32:
                perform_downscale(uint32_t());
                break;
            default:
                // should not happen
                LOG_ERROR("Unhandled format 0x{:0X}", fmt::underlying(src->format));
                break;
            }
        }

        delete src;
        delete dst;
    };

    if (renderer.current_backend == Backend::Vulkan && renderer.features.enable_memory_mapping && !renderer.disable_surface_sync) {
        if (dynamic_cast<vulkan::VKState &>(renderer).surface_cache.check_for_surface(mem, src->address.address(), downscale_operation, dst->address.address()))
            // let the vulkan surface cache handle it
            return;
    }

    downscale_operation();
}

COMMAND(handle_transfer_fill) {
    TRACY_FUNC_COMMANDS(handle_transfer_fill);
    const uint32_t fill_color = helper.pop<uint32_t>();
    const SceGxmTransferImage *dest = helper.pop<SceGxmTransferImage *>();

    const auto bpp = gxm::get_bits_per_pixel(dest->format);

    const uint32_t bytes_per_pixel = (bpp + 7) >> 3;
    for (uint32_t y = 0; y < dest->height; y++) {
        for (uint32_t x = 0; x < dest->width; x++) {
            // Set offset of destination
            const auto dest_offset = ((x + dest->x) * bytes_per_pixel) + ((y + dest->y) * dest->stride);

            // Set pointer of destination
            auto dest_ptr = (uint8_t *)dest->address.get(mem) + dest_offset;

            // Fill color in destination
            memcpy(dest_ptr, &fill_color, bytes_per_pixel);
        }
    }

    // TODO: handle case where dest is a cached surface

    delete dest;
}

} // namespace renderer
