/*

 * Copyright (C) 2006 Evgeniy Stepanov <eugeni.stepanov@gmail.com>

 *

 * This file is part of mpv.

 *

 * mpv is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * mpv 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 Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.

 */

#include <string.h>

#include <stdarg.h>

#include <stdbool.h>

#include <assert.h>

#include "config.h"

#include <ass/ass.h>

#include <ass/ass_types.h>

#if HAVE_SUBRANDR

#include <subrandr/subrandr.h>

#endif

#include "common/common.h"

#include "packer.h"

#include "img_convert.h"

#include "osd.h"

#include "video/out/bitmap_packer.h"

#include "video/mp_image.h"

struct mp_sub_packer {

    struct sub_bitmap *cached_parts; // only for the array memory

    struct sub_bitmap *cached_subrandr_images;

    struct mp_image *cached_img;

    struct sub_bitmaps cached_subs;

    bool cached_subs_valid;

    struct sub_bitmap rgba_imgs[MP_SUB_BB_LIST_MAX];

    struct bitmap_packer *packer;

};

// Free with talloc_free().

struct mp_sub_packer *mp_sub_packer_alloc(void *ta_parent)

{

    struct mp_sub_packer *p = talloc_zero(ta_parent, struct mp_sub_packer);

    p->packer = talloc_zero(p, struct bitmap_packer);

    p->packer->padding = 1; // assume bilinear sampling

    return p;

}

static bool pack(struct mp_sub_packer *p, struct sub_bitmaps *res, int imgfmt)

{

    packer_set_size(p->packer, res->num_parts);

    for (int n = 0; n < res->num_parts; n++)

        p->packer->in[n] = (struct pos){res->parts[n].w, res->parts[n].h};

    if (p->packer->count == 0 || packer_pack(p->packer) < 0)

        return false;

    struct pos bb[2];

    packer_get_bb(p->packer, bb);

    res->packed_w = bb[1].x;

    res->packed_h = bb[1].y;

    if (!p->cached_img || p->cached_img->w < res->packed_w ||

                          p->cached_img->h < res->packed_h ||

                          p->cached_img->imgfmt != imgfmt)

    {

        talloc_free(p->cached_img);

        p->cached_img = mp_image_alloc(imgfmt, p->packer->w, p->packer->h);

        if (!p->cached_img) {

            packer_reset(p->packer);

            return false;

        }

        talloc_steal(p, p->cached_img);

    }

    if (!mp_image_make_writeable(p->cached_img)) {

        packer_reset(p->packer);

        return false;

    }

    res->packed = p->cached_img;

    for (int n = 0; n < res->num_parts; n++) {

        struct sub_bitmap *b = &res->parts[n];

        struct pos pos = p->packer->result[n];

        b->src_x = pos.x;

        b->src_y = pos.y;

    }

    return true;

}

static void fill_padding_1(uint8_t *base, int w, int h, int stride, int padding)

{

    for (int row = 0; row < h; ++row) {

        uint8_t *row_ptr = base + row * stride;

        uint8_t left_pixel = row_ptr[0];

        uint8_t right_pixel = row_ptr[w - 1];

        for (int i = 1; i <= padding; ++i)

            row_ptr[-i] = left_pixel;

        for (int i = 0; i < padding; ++i)

            row_ptr[w + i] = right_pixel;

    }

    int row_bytes = (w + 2 * padding);

    uint8_t *top_row = base - padding;

    for (int i = 1; i <= padding; ++i)

        memcpy(base - i * stride - padding, top_row, row_bytes);

    uint8_t *last_row = base + (h - 1) * stride - padding;

    for (int i = 0; i < padding; ++i)

        memcpy(base + (h + i) * stride - padding, last_row, row_bytes);

}

static void fill_padding_4(uint8_t *base, int w, int h, int stride, int padding)

{

    for (int row = 0; row < h; ++row) {

        uint32_t *row_ptr = (uint32_t *)(base + row * stride);

        uint32_t left_pixel = row_ptr[0];

        uint32_t right_pixel = row_ptr[w - 1];

        for (int i = 1; i <= padding; ++i)

            row_ptr[-i] = left_pixel;

        for (int i = 0; i < padding; ++i)

            row_ptr[w + i] = right_pixel;

    }

    int row_bytes = (w + 2 * padding) * 4;

    uint8_t *top_row = base - padding * 4;

    for (int i = 1; i <= padding; ++i)

        memcpy(base - i * stride - padding * 4, top_row, row_bytes);

    uint8_t *last_row = base + (h - 1) * stride - padding * 4;

    for (int i = 0; i < padding; ++i)

        memcpy(base + (h + i) * stride - padding * 4, last_row, row_bytes);

}

static void draw_ass_rgba(unsigned char *src, int src_w, int src_h,

                          int src_stride, unsigned char *dst, size_t dst_stride,

                          int dst_x, int dst_y, uint32_t color)

{

    const unsigned int r = (color >> 24) & 0xff;

    const unsigned int g = (color >> 16) & 0xff;

    const unsigned int b = (color >>  8) & 0xff;

    const unsigned int a = 0xff - (color & 0xff);

    dst += dst_y * dst_stride + dst_x * 4;

    for (int y = 0; y < src_h; y++, dst += dst_stride, src += src_stride) {

        uint32_t *dstrow = (uint32_t *) dst;

        for (int x = 0; x < src_w; x++) {

            const unsigned int v = src[x];

            int rr = (r * a * v);

            int gg = (g * a * v);

            int bb = (b * a * v);

            int aa =      a * v;

            uint32_t dstpix = dstrow[x];

            unsigned int dstb =  dstpix        & 0xFF;

            unsigned int dstg = (dstpix >>  8) & 0xFF;

            unsigned int dstr = (dstpix >> 16) & 0xFF;

            unsigned int dsta = (dstpix >> 24) & 0xFF;

            dstb = (bb       + dstb * (255 * 255 - aa)) / (255 * 255);

            dstg = (gg       + dstg * (255 * 255 - aa)) / (255 * 255);

            dstr = (rr       + dstr * (255 * 255 - aa)) / (255 * 255);

            dsta = (aa * 255 + dsta * (255 * 255 - aa)) / (255 * 255);

            dstrow[x] = dstb | (dstg << 8) | (dstr << 16) | (dsta << 24);

        }

    }

}

static bool pack_libass(struct mp_sub_packer *p, struct sub_bitmaps *res)

{

    if (!pack(p, res, IMGFMT_Y8))

        return false;

    int padding = p->packer->padding;

    uint8_t *base = res->packed->planes[0];

    int stride = res->packed->stride[0];

    for (int n = 0; n < res->num_parts; n++) {

        struct sub_bitmap *b = &res->parts[n];

        void *pdata = base + b->src_y * stride + b->src_x;

        memcpy_pic(pdata, b->bitmap, b->w, b->h, stride, b->stride);

        fill_padding_1(pdata, b->w, b->h, stride, padding);

        b->bitmap = pdata;

        b->stride = stride;

    }

    return true;

}

static bool pack_rgba(struct mp_sub_packer *p, struct sub_bitmaps *res)

{

    struct mp_rect bb_list[MP_SUB_BB_LIST_MAX];

    int num_bb = mp_get_sub_bb_list(res, bb_list, MP_SUB_BB_LIST_MAX);

    struct sub_bitmaps imgs = {

        .change_id = res->change_id,

        .format = SUBBITMAP_BGRA,

        .parts = p->rgba_imgs,

        .num_parts = num_bb,

    };

    for (int n = 0; n < imgs.num_parts; n++) {

        imgs.parts[n].w = bb_list[n].x1 - bb_list[n].x0;

        imgs.parts[n].h = bb_list[n].y1 - bb_list[n].y0;

    }

    if (!pack(p, &imgs, IMGFMT_BGRA))

        return false;

    int padding = p->packer->padding;

    uint8_t *base = imgs.packed->planes[0];

    int stride = imgs.packed->stride[0];

    for (int n = 0; n < num_bb; n++) {

        struct mp_rect bb = bb_list[n];

        struct sub_bitmap *b = &imgs.parts[n];

        b->x = bb.x0;

        b->y = bb.y0;

        b->w = b->dw = mp_rect_w(bb);

        b->h = b->dh = mp_rect_h(bb);

        b->stride = stride;

        b->bitmap = base + b->stride * b->src_y + b->src_x * 4;

        memset_pic(b->bitmap, 0, b->w * 4, b->h, b->stride);

        for (int i = 0; i < res->num_parts; i++) {

            struct sub_bitmap *s = &res->parts[i];

            // Assume mp_get_sub_bb_list() never splits sub bitmaps

            // So we don't clip/adjust the size of the sub bitmap

            if (s->x >= b->x + b->w || s->x + s->w <= b->x ||

                s->y >= b->y + b->h || s->y + s->h <= b->y)

                continue;

            draw_ass_rgba(s->bitmap, s->w, s->h, s->stride,

                          b->bitmap, b->stride,

                          s->x - b->x, s->y - b->y,

                          s->libass.color);

        }

        fill_padding_4(b->bitmap, b->w, b->h, b->stride, padding);

    }

    *res = imgs;

    return true;

}

// Pack the contents of image_lists[0] to image_lists[num_image_lists-1] into

// a single image, and make *out point to it. *out is completely overwritten.

// If libass reported any change, image_lists_changed must be set (it then

// repacks all images). preferred_osd_format can be set to a desired

// sub_bitmap_format. Currently, only SUBBITMAP_LIBASS is supported.

void mp_sub_packer_pack_ass(struct mp_sub_packer *p, ASS_Image **image_lists,

                        int num_image_lists, bool image_lists_changed, bool video_color_space,

                        int preferred_osd_format, struct sub_bitmaps *out)

{

    int format = preferred_osd_format == SUBBITMAP_BGRA ? SUBBITMAP_BGRA

                                                        : SUBBITMAP_LIBASS;

    if (p->cached_subs_valid && !image_lists_changed &&

        p->cached_subs.format == format)

    {

        *out = p->cached_subs;

        return;

    }

    *out = (struct sub_bitmaps){.change_id = 1};

    p->cached_subs_valid = false;

    struct sub_bitmaps res = {

        .change_id = image_lists_changed,

        .format = SUBBITMAP_LIBASS,

        .parts = p->cached_parts,

        .video_color_space = video_color_space,

    };

    for (int n = 0; n < num_image_lists; n++) {

        for (struct ass_image *img = image_lists[n]; img; img = img->next) {

            if (img->w == 0 || img->h == 0)

                continue;

            MP_TARRAY_GROW(p, p->cached_parts, res.num_parts);

            res.parts = p->cached_parts;

            struct sub_bitmap *b = &res.parts[res.num_parts];

            b->bitmap = img->bitmap;

            b->stride = img->stride;

            b->libass.color = img->color;

            b->dw = b->w = img->w;

            b->dh = b->h = img->h;

            b->x = img->dst_x;

            b->y = img->dst_y;

            res.num_parts++;

        }

    }

    bool r = false;

    if (format == SUBBITMAP_BGRA) {

        r = pack_rgba(p, &res);

    } else {

        r = pack_libass(p, &res);

    }

    if (!r)

        return;

    *out = res;

    p->cached_subs = res;

    p->cached_subs.change_id = 0;

    p->cached_subs_valid = true;

}

#if HAVE_SUBRANDR

// Pack the images in `res` into a BGRA8 atlas and populate `res->parts`

// with instances of the images as described by `pass`.

static bool pack_subrandr(struct mp_sub_packer *p, struct sub_bitmaps *res,

                          struct sbr_instanced_raster_pass *pass)

{

    if (!pack(p, res, IMGFMT_BGRA))

        return false;

    int padding = p->packer->padding;

    sbr_bgra8 *base = (sbr_bgra8 *)res->packed->planes[0];

    int byte_stride = res->packed->stride[0];

    int pixel_stride = byte_stride / 4;

    struct sbr_output_instance *instances = sbr_instanced_raster_pass_get_instances(pass);

    for (int n = 0; n < res->num_parts; n++) {

        struct sub_bitmap *b = &res->parts[n];

        sbr_output_image_rasterize_into(b->subrandr.image, pass, b->src_x, b->src_y,

                                        base, res->packed_w, res->packed_h, pixel_stride);

        void *pdata = base + b->src_y * pixel_stride + b->src_x;

        fill_padding_4(pdata, b->w, b->h, byte_stride, padding);

        b->bitmap = pdata;

    }

    res->parts = NULL;

    res->num_parts = 0;

    res->format = SUBBITMAP_BGRA;

    for (struct sbr_output_instance *instance = instances; instance; instance = instance->next) {

        if (!instance->base->user_data)

            continue;

        MP_TARRAY_GROW(p, p->cached_parts, res->num_parts);

        res->parts = p->cached_parts;

        struct sub_bitmap *inst_b = &res->parts[res->num_parts];

        struct sub_bitmap *image_b = &p->cached_subrandr_images[(size_t)instance->base->user_data - 1];

        *inst_b = (struct sub_bitmap){

            .x = instance->dst_x,      .y = instance->dst_y,

            .dw = instance->dst_width, .dh = instance->dst_height,

            .w = instance->src_width,  .h = instance->src_height,

            .src_x = image_b->src_x + instance->src_off_x,

            .src_y = image_b->src_y + instance->src_off_y,

            .bitmap = image_b->bitmap, .stride = byte_stride,

        };

        res->num_parts++;

    }

    return true;

}

// Pack the images in `pass` into a single image, make `out` point to it,

// and populate `out->parts` to correctly describe all instances in `pass`.

void mp_sub_packer_pack_sbr(struct mp_sub_packer *p, sbr_instanced_raster_pass *pass,

                            struct sub_bitmaps *out)

{

    *out = (struct sub_bitmaps){.change_id = 1};

    p->cached_subs_valid = false;

    struct sub_bitmaps res = {

        .change_id = (unsigned)p->cached_subs.change_id + 1,

        .format = SUBBITMAP_SUBRANDR,

        .parts = p->cached_parts,

        .video_color_space = false,

    };

    struct sbr_output_instance *instances = sbr_instanced_raster_pass_get_instances(pass);

    for (struct sbr_output_instance *instance = instances; instance; instance = instance->next) {

        // If `user_data` is non-null then this base image was already appended.

        if (instance->base->user_data)

            continue;

        MP_TARRAY_GROW(p, p->cached_subrandr_images, res.num_parts);

        res.parts = p->cached_subrandr_images;

        struct sub_bitmap *b = &res.parts[res.num_parts];

        b->subrandr.image = instance->base;

        b->w = instance->base->width, b->h = instance->base->height;

        // Store the index of the `sub_bitmap` for this output image into `user_data`.

        // This index is incremented by one to differentiate index `0` from an absent index.

        // Will be read in `pack_subrandr` after packing to determine where each image

        // was actually packed to in the atlas.

        instance->base->user_data = (void *)(uintptr_t)(res.num_parts + 1);

        res.num_parts++;

    }

    if (!pack_subrandr(p, &res, pass))

        return;

    *out = res;

    p->cached_subs = res;

    p->cached_subs_valid = true;

}

const struct sub_bitmaps *mp_sub_packer_get_cached(struct mp_sub_packer *p) {

    if (p->cached_subs_valid)

        return &p->cached_subs;

    return NULL;

}

#endif