/*
 * Copyright (c) 2012-2013 Oka Motofumi (chikuzen.mo at gmail dot com)
 * Copyright (c) 2015 Paul B Mahol
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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.
 *
 * FFmpeg 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 FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "libavutil/imgutils.h"
#include "libavutil/pixdesc.h"
#include "libavutil/opt.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"

typedef struct NContext {
    const AVClass *class;
    int planeheight[4];
    int planewidth[4];
    int nb_planes;
    int threshold[4];
    int coordinates;
    uint8_t *buffer;

    void (*filter)(uint8_t *dst, const uint8_t *p1, int width,
                   int threshold, const uint8_t *coordinates[], int coord);
} NContext;

static int query_formats(AVFilterContext *ctx)
{
    static const enum AVPixelFormat pix_fmts[] = {
        AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA420P,
        AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ422P,AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ411P,
        AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
        AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE
    };

    return ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
}

static av_cold void uninit(AVFilterContext *ctx)
{
    NContext *s = ctx->priv;

    av_freep(&s->buffer);
}

static inline void line_copy8(uint8_t *line, const uint8_t *srcp, int width, int mergin)
{
    int i;

    memcpy(line, srcp, width);

    for (i = mergin; i > 0; i--) {
        line[-i] = line[i];
        line[width - 1 + i] = line[width - 1 - i];
    }
}

static void erosion(uint8_t *dst, const uint8_t *p1, int width,
                    int threshold, const uint8_t *coordinates[], int coord)
{
    int x, i;

    for (x = 0; x < width; x++) {
        int min = p1[x];
        int limit = FFMAX(min - threshold, 0);

        for (i = 0; i < 8; i++) {
            if (coord & (1 << i)) {
                min = FFMIN(min, *(coordinates[i] + x));
            }
            min = FFMAX(min, limit);
        }

        dst[x] = min;
    }
}

static void dilation(uint8_t *dst, const uint8_t *p1, int width,
                     int threshold, const uint8_t *coordinates[], int coord)
{
    int x, i;

    for (x = 0; x < width; x++) {
        int max = p1[x];
        int limit = FFMIN(max + threshold, 255);

        for (i = 0; i < 8; i++) {
            if (coord & (1 << i)) {
                max = FFMAX(max, *(coordinates[i] + x));
            }
            max = FFMIN(max, limit);
        }

        dst[x] = max;
    }
}

static void deflate(uint8_t *dst, const uint8_t *p1, int width,
                    int threshold, const uint8_t *coordinates[], int coord)
{
    int x, i;

    for (x = 0; x < width; x++) {
        int sum = 0;
        int limit = FFMAX(p1[x] - threshold, 0);

        for (i = 0; i < 8; sum += *(coordinates[i++] + x));

        dst[x] = FFMAX(FFMIN(sum / 8, p1[x]), limit);
    }
}

static void inflate(uint8_t *dst, const uint8_t *p1, int width,
                    int threshold, const uint8_t *coordinates[], int coord)
{
    int x, i;

    for (x = 0; x < width; x++) {
        int sum = 0;
        int limit = FFMIN(p1[x] + threshold, 255);

        for (i = 0; i < 8; sum += *(coordinates[i++] + x));

        dst[x] = FFMIN(FFMAX(sum / 8, p1[x]), limit);
    }
}

static int config_input(AVFilterLink *inlink)
{
    AVFilterContext *ctx = inlink->dst;
    NContext *s = ctx->priv;
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
    int ret;

    if ((ret = av_image_fill_linesizes(s->planewidth, inlink->format, inlink->w)) < 0)
        return ret;

    s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
    s->planeheight[0] = s->planeheight[3] = inlink->h;

    s->nb_planes = av_pix_fmt_count_planes(inlink->format);
    s->buffer = av_malloc(3 * (s->planewidth[0] + 32));
    if (!s->buffer)
        return AVERROR(ENOMEM);

    if (!strcmp(ctx->filter->name, "erosion"))
        s->filter = erosion;
    else if (!strcmp(ctx->filter->name, "dilation"))
        s->filter = dilation;
    else if (!strcmp(ctx->filter->name, "deflate"))
        s->filter = deflate;
    else if (!strcmp(ctx->filter->name, "inflate"))
        s->filter = inflate;

    return 0;
}

static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
    AVFilterContext *ctx = inlink->dst;
    AVFilterLink *outlink = ctx->outputs[0];
    NContext *s = ctx->priv;
    AVFrame *out;
    int plane, y;

    out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
    if (!out) {
        av_frame_free(&in);
        return AVERROR(ENOMEM);
    }
    av_frame_copy_props(out, in);

    for (plane = 0; plane < s->nb_planes; plane++) {
        const int threshold = s->threshold[plane];

        if (threshold) {
            const uint8_t *src = in->data[plane];
            uint8_t *dst = out->data[plane];
            int stride = in->linesize[plane];
            int height = s->planeheight[plane];
            int width  = s->planewidth[plane];
            uint8_t *p0 = s->buffer + 16;
            uint8_t *p1 = p0 + s->planewidth[0];
            uint8_t *p2 = p1 + s->planewidth[0];
            uint8_t *orig = p0, *end = p2;

            line_copy8(p0, src + stride, width, 1);
            line_copy8(p1, src, width, 1);

            for (y = 0; y < height; y++) {
                const uint8_t *coordinates[] = { p0 - 1, p0, p0 + 1,
                                                 p1 - 1,     p1 + 1,
                                                 p2 - 1, p2, p2 + 1};
                src += stride * (y < height - 1 ? 1 : -1);
                line_copy8(p2, src, width, 1);

                s->filter(dst, p1, width, threshold, coordinates, s->coordinates);

                p0 = p1;
                p1 = p2;
                p2 = (p2 == end) ? orig: p2 + s->planewidth[0];
                dst += out->linesize[plane];
            }
        } else {
            av_image_copy_plane(out->data[plane], out->linesize[plane],
                                in->data[plane], in->linesize[plane],
                                s->planewidth[plane], s->planeheight[plane]);
        }
    }

    av_frame_free(&in);
    return ff_filter_frame(outlink, out);
}

static const AVFilterPad neighbor_inputs[] = {
    {
        .name         = "default",
        .type         = AVMEDIA_TYPE_VIDEO,
        .filter_frame = filter_frame,
        .config_props = config_input,
    },
    { NULL }
};

static const AVFilterPad neighbor_outputs[] = {
    {
        .name = "default",
        .type = AVMEDIA_TYPE_VIDEO,
    },
    { NULL }
};

#define OFFSET(x) offsetof(NContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

#define DEFINE_NEIGHBOR_FILTER(name_, description_)          \
AVFILTER_DEFINE_CLASS(name_);                                \
                                                             \
AVFilter ff_vf_##name_ = {                                   \
    .name          = #name_,                                 \
    .description   = NULL_IF_CONFIG_SMALL(description_),     \
    .priv_size     = sizeof(NContext),                       \
    .priv_class    = &name_##_class,                         \
    .uninit        = uninit,                                 \
    .query_formats = query_formats,                          \
    .inputs        = neighbor_inputs,                        \
    .outputs       = neighbor_outputs,                       \
    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC, \
}

#if CONFIG_EROSION_FILTER

static const AVOption erosion_options[] = {
    { "threshold0",  "set threshold for 1st plane",   OFFSET(threshold[0]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { "threshold1",  "set threshold for 2nd plane",   OFFSET(threshold[1]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { "threshold2",  "set threshold for 3rd plane",   OFFSET(threshold[2]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { "threshold3",  "set threshold for 4th plane",   OFFSET(threshold[3]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { "coordinates", "set coordinates",               OFFSET(coordinates),    AV_OPT_TYPE_INT, {.i64=255},   0, 255,   FLAGS },
    { NULL }
};

DEFINE_NEIGHBOR_FILTER(erosion, "Apply erosion effect.");

#endif /* CONFIG_EROSION_FILTER */

#if CONFIG_DILATION_FILTER

static const AVOption dilation_options[] = {
    { "threshold0",  "set threshold for 1st plane",   OFFSET(threshold[0]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { "threshold1",  "set threshold for 2nd plane",   OFFSET(threshold[1]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { "threshold2",  "set threshold for 3rd plane",   OFFSET(threshold[2]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { "threshold3",  "set threshold for 4th plane",   OFFSET(threshold[3]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { "coordinates", "set coordinates",               OFFSET(coordinates),    AV_OPT_TYPE_INT, {.i64=255},   0, 255,   FLAGS },
    { NULL }
};

DEFINE_NEIGHBOR_FILTER(dilation, "Apply dilation effect.");

#endif /* CONFIG_DILATION_FILTER */

#if CONFIG_DEFLATE_FILTER

static const AVOption deflate_options[] = {
    { "threshold0", "set threshold for 1st plane",   OFFSET(threshold[0]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { "threshold1", "set threshold for 2nd plane",   OFFSET(threshold[1]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { "threshold2", "set threshold for 3rd plane",   OFFSET(threshold[2]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { "threshold3", "set threshold for 4th plane",   OFFSET(threshold[3]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { NULL }
};

DEFINE_NEIGHBOR_FILTER(deflate, "Apply deflate effect.");

#endif /* CONFIG_DEFLATE_FILTER */

#if CONFIG_INFLATE_FILTER

static const AVOption inflate_options[] = {
    { "threshold0", "set threshold for 1st plane",   OFFSET(threshold[0]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { "threshold1", "set threshold for 2nd plane",   OFFSET(threshold[1]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { "threshold2", "set threshold for 3rd plane",   OFFSET(threshold[2]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { "threshold3", "set threshold for 4th plane",   OFFSET(threshold[3]),   AV_OPT_TYPE_INT, {.i64=65535}, 0, 65535, FLAGS },
    { NULL }
};

DEFINE_NEIGHBOR_FILTER(inflate, "Apply inflate effect.");

#endif /* CONFIG_INFLATE_FILTER */