/*
 * This file is part of mpv.
 *
 * mpv 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.
 *
 * 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with mpv.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <sys/types.h>
#include <libavutil/common.h>
#include <libavutil/mem.h>

#include "config.h"

#include "common/common.h"
#include "common/global.h"
#include "common/msg.h"
#include "options/m_option.h"
#include "options/m_config.h"

#include "options/options.h"

#include "video/img_format.h"
#include "video/mp_image.h"
#include "video/mp_image_pool.h"
#include "vf.h"

extern const vf_info_t vf_info_crop;
extern const vf_info_t vf_info_expand;
extern const vf_info_t vf_info_scale;
extern const vf_info_t vf_info_format;
extern const vf_info_t vf_info_noformat;
extern const vf_info_t vf_info_flip;
extern const vf_info_t vf_info_rotate;
extern const vf_info_t vf_info_mirror;
extern const vf_info_t vf_info_eq;
extern const vf_info_t vf_info_gradfun;
extern const vf_info_t vf_info_dsize;
extern const vf_info_t vf_info_pullup;
extern const vf_info_t vf_info_sub;
extern const vf_info_t vf_info_yadif;
extern const vf_info_t vf_info_stereo3d;
extern const vf_info_t vf_info_dlopen;
extern const vf_info_t vf_info_lavfi;
extern const vf_info_t vf_info_vaapi;
extern const vf_info_t vf_info_vapoursynth;
extern const vf_info_t vf_info_vapoursynth_lazy;
extern const vf_info_t vf_info_vdpaupp;
extern const vf_info_t vf_info_vdpaurb;
extern const vf_info_t vf_info_buffer;

// list of available filters:
static const vf_info_t *const filter_list[] = {
    &vf_info_crop,
    &vf_info_expand,
    &vf_info_scale,
    &vf_info_format,
    &vf_info_noformat,
    &vf_info_flip,

#if HAVE_LIBAVFILTER
    &vf_info_mirror,
    &vf_info_lavfi,
    &vf_info_rotate,
    &vf_info_gradfun,
    &vf_info_pullup,
    &vf_info_yadif,
    &vf_info_stereo3d,
#endif

    &vf_info_eq,
    &vf_info_dsize,
    &vf_info_sub,
    &vf_info_buffer,
#if HAVE_DLOPEN
    &vf_info_dlopen,
#endif
#if HAVE_VAPOURSYNTH_CORE && HAVE_VAPOURSYNTH
    &vf_info_vapoursynth,
#endif
#if HAVE_VAPOURSYNTH_CORE && HAVE_VAPOURSYNTH_LAZY
    &vf_info_vapoursynth_lazy,
#endif
#if HAVE_VAAPI
    &vf_info_vaapi,
#endif
#if HAVE_VDPAU
    &vf_info_vdpaupp,
    &vf_info_vdpaurb,
#endif
    NULL
};

static void vf_uninit_filter(vf_instance_t *vf);

static bool get_desc(struct m_obj_desc *dst, int index)
{
    if (index >= MP_ARRAY_SIZE(filter_list) - 1)
        return false;
    const vf_info_t *vf = filter_list[index];
    *dst = (struct m_obj_desc) {
        .name = vf->name,
        .description = vf->description,
        .priv_size = vf->priv_size,
        .priv_defaults = vf->priv_defaults,
        .options = vf->options,
        .p = vf,
        .print_help = vf->print_help,
    };
    return true;
}

// For the vf option
const struct m_obj_list vf_obj_list = {
    .get_desc = get_desc,
    .description = "video filters",
};

// Try the cmd on each filter (starting with the first), and stop at the first
// filter which does not return CONTROL_UNKNOWN for it.
int vf_control_any(struct vf_chain *c, int cmd, void *arg)
{
    for (struct vf_instance *cur = c->first; cur; cur = cur->next) {
        if (cur->control) {
            int r = cur->control(cur, cmd, arg);
            if (r != CONTROL_UNKNOWN)
                return r;
        }
    }
    return CONTROL_UNKNOWN;
}

int vf_control_by_label(struct vf_chain *c,int cmd, void *arg, bstr label)
{
    char *label_str = bstrdup0(NULL, label);
    struct vf_instance *cur = vf_find_by_label(c, label_str);
    talloc_free(label_str);
    if (cur) {
        return cur->control ? cur->control(cur, cmd, arg) : CONTROL_NA;
    } else {
        return CONTROL_UNKNOWN;
    }
}

static void vf_control_all(struct vf_chain *c, int cmd, void *arg)
{
    for (struct vf_instance *cur = c->first; cur; cur = cur->next) {
        if (cur->control)
            cur->control(cur, cmd, arg);
    }
}

static void vf_fix_img_params(struct mp_image *img, struct mp_image_params *p)
{
    // Filters must absolutely set these correctly.
    assert(img->w == p->w && img->h == p->h);
    assert(img->imgfmt == p->imgfmt);
    // Too many things don't set this correctly.
    // If --colormatrix is used, decoder and filter chain disagree too.
    // In general, it's probably more convenient to force these here,
    // instead of requiring filters to set these correctly.
    img->params = *p;
}

// Get a new image for filter output, with size and pixel format according to
// the last vf_config call.
struct mp_image *vf_alloc_out_image(struct vf_instance *vf)
{
    struct mp_image_params *p = &vf->fmt_out;
    assert(p->imgfmt);
    struct mp_image *img = mp_image_pool_get(vf->out_pool, p->imgfmt, p->w, p->h);
    if (img)
        vf_fix_img_params(img, p);
    return img;
}

// Returns false on failure; then the image can't be written to.
bool vf_make_out_image_writeable(struct vf_instance *vf, struct mp_image *img)
{
    struct mp_image_params *p = &vf->fmt_out;
    assert(p->imgfmt);
    assert(p->imgfmt == img->imgfmt);
    assert(p->w == img->w && p->h == img->h);
    return mp_image_pool_make_writeable(vf->out_pool, img);
}

//============================================================================

// The default callback assumes all formats are passed through.
static int vf_default_query_format(struct vf_instance *vf, unsigned int fmt)
{
    return vf_next_query_format(vf, fmt);
}

void vf_print_filter_chain(struct vf_chain *c, int msglevel,
                           struct vf_instance *vf)
{
    if (!mp_msg_test(c->log, msglevel))
        return;

    char b[128] = {0};

    mp_snprintf_cat(b, sizeof(b), "%s", mp_image_params_to_str(&c->input_params));
    mp_msg(c->log, msglevel, "  [vd] %s\n", b);

    for (vf_instance_t *f = c->first; f; f = f->next) {
        b[0] = '\0';
        mp_snprintf_cat(b, sizeof(b), "  [%s] ", f->info->name);
        mp_snprintf_cat(b, sizeof(b), "%s", mp_image_params_to_str(&f->fmt_out));
        if (f->autoinserted)
            mp_snprintf_cat(b, sizeof(b), " [a]");
        if (f == vf)
            mp_snprintf_cat(b, sizeof(b), "   <---");
        mp_msg(c->log, msglevel, "%s\n", b);
    }
}

static struct vf_instance *vf_open(struct vf_chain *c, const char *name,
                                   char **args)
{
    struct m_obj_desc desc;
    if (!m_obj_list_find(&desc, &vf_obj_list, bstr0(name))) {
        MP_ERR(c, "Couldn't find video filter '%s'.\n", name);
        return NULL;
    }
    vf_instance_t *vf = talloc_zero(NULL, struct vf_instance);
    *vf = (vf_instance_t) {
        .info = desc.p,
        .log = mp_log_new(vf, c->log, name),
        .hwdec = c->hwdec,
        .query_format = vf_default_query_format,
        .out_pool = talloc_steal(vf, mp_image_pool_new(16)),
        .chain = c,
    };
    struct m_config *config = m_config_from_obj_desc(vf, vf->log, &desc);
    if (m_config_apply_defaults(config, name, c->opts->vf_defs) < 0)
        goto error;
    if (m_config_set_obj_params(config, args) < 0)
        goto error;
    vf->priv = config->optstruct;
    int retcode = vf->info->open(vf);
    if (retcode < 1)
        goto error;
    return vf;

error:
    MP_ERR(c, "Creating filter '%s' failed.\n", name);
    talloc_free(vf);
    return NULL;
}

static vf_instance_t *vf_open_filter(struct vf_chain *c, const char *name,
                                     char **args)
{
    int i, l = 0;
    for (i = 0; args && args[2 * i]; i++)
        l += 1 + strlen(args[2 * i]) + 1 + strlen(args[2 * i + 1]);
    l += strlen(name);
    char str[l + 1];
    char *p = str;
    p += sprintf(str, "%s", name);
    for (i = 0; args && args[2 * i]; i++)
        p += sprintf(p, " %s=%s", args[2 * i], args[2 * i + 1]);
    MP_INFO(c, "Opening video filter: [%s]\n", str);
    return vf_open(c, name, args);
}

void vf_remove_filter(struct vf_chain *c, struct vf_instance *vf)
{
    assert(vf != c->first && vf != c->last); // these are sentinels
    struct vf_instance *prev = c->first;
    while (prev && prev->next != vf)
        prev = prev->next;
    assert(prev); // not inserted
    prev->next = vf->next;
    vf_uninit_filter(vf);
}

struct vf_instance *vf_append_filter(struct vf_chain *c, const char *name,
                                     char **args)
{
    struct vf_instance *vf = vf_open_filter(c, name, args);
    if (vf) {
        // Insert it before the last filter, which is the "out" pseudo-filter
        // (But after the "in" pseudo-filter)
        struct vf_instance **pprev = &c->first->next;
        while (*pprev && (*pprev)->next)
            pprev = &(*pprev)->next;
        vf->next = *pprev ? *pprev : NULL;
        *pprev = vf;
    }
    return vf;
}

int vf_append_filter_list(struct vf_chain *c, struct m_obj_settings *list)
{
    for (int n = 0; list && list[n].name; n++) {
        struct vf_instance *vf =
            vf_append_filter(c, list[n].name, list[n].attribs);
        if (vf) {
            if (list[n].label) {
                vf->label = talloc_strdup(vf, list[n].label);
            } else {
                for (int i = 0; i < 100; i++) {
                    char* label = talloc_asprintf(vf, "%s.%02d", list[n].name, i);
                    if (vf_find_by_label(c, label)) {
                        talloc_free(label);
                    } else {
                        vf->label = label;
                        break;
                    }
                }
            }
        }
    }
    return 0;
}

// Used by filters to add a filtered frame to the output queue.
// Ownership of img is transferred from caller to the filter chain.
void vf_add_output_frame(struct vf_instance *vf, struct mp_image *img)
{
    if (img) {
        vf_fix_img_params(img, &vf->fmt_out);
        MP_TARRAY_APPEND(vf, vf->out_queued, vf->num_out_queued, img);
    }
}

static bool vf_has_output_frame(struct vf_instance *vf)
{
    if (!vf->num_out_queued && vf->filter_out) {
        if (vf->filter_out(vf) < 0)
            MP_ERR(vf, "Error filtering frame.\n");
    }
    return vf->num_out_queued > 0;
}

static struct mp_image *vf_dequeue_output_frame(struct vf_instance *vf)
{
    struct mp_image *res = NULL;
    if (vf_has_output_frame(vf)) {
        res = vf->out_queued[0];
        MP_TARRAY_REMOVE_AT(vf->out_queued, vf->num_out_queued, 0);
    }
    return res;
}

static int vf_do_filter(struct vf_instance *vf, struct mp_image *img)
{
    assert(vf->fmt_in.imgfmt);
    if (img)
        assert(mp_image_params_equal(&img->params, &vf->fmt_in));

    if (vf->filter_ext) {
        int r = vf->filter_ext(vf, img);
        if (r < 0)
            MP_ERR(vf, "Error filtering frame.\n");
        return r;
    } else {
        if (img) {
            if (vf->filter)
                img = vf->filter(vf, img);
            vf_add_output_frame(vf, img);
        }
        return 0;
    }
}

// Input a frame into the filter chain. Ownership of img is transferred.
// Return >= 0 on success, < 0 on failure (even if output frames were produced)
int vf_filter_frame(struct vf_chain *c, struct mp_image *img)
{
    assert(img);
    if (c->initialized < 1) {
        talloc_free(img);
        return -1;
    }
    assert(mp_image_params_equal(&img->params, &c->input_params));
    vf_fix_img_params(img, &c->override_params);
    return vf_do_filter(c->first, img);
}

// Similar to vf_output_frame(), but only ensure that the filter "until" has
// output, instead of the end of the filter chain.
static int vf_output_frame_until(struct vf_chain *c, struct vf_instance *until,
                                 bool eof)
{
    if (until->num_out_queued)
        return 1;
    if (c->initialized < 1)
        return -1;
    while (1) {
        struct vf_instance *last = NULL;
        for (struct vf_instance * cur = c->first; cur; cur = cur->next) {
            // Flush remaining frames on EOF, but do that only if the previous
            // filters have been flushed (i.e. they have no more output).
            if (eof && !last) {
                int r = vf_do_filter(cur, NULL);
                if (r < 0)
                    return r;
            }
            if (vf_has_output_frame(cur))
                last = cur;
            if (cur == until)
                break;
        }
        if (!last)
            return 0;
        if (last == until)
            return 1;
        int r = vf_do_filter(last->next, vf_dequeue_output_frame(last));
        if (r < 0)
            return r;
    }
}

// Output the next queued image (if any) from the full filter chain.
// The frame can be retrieved with vf_read_output_frame().
//  eof: if set, assume there's no more input i.e. vf_filter_frame() will
//       not be called (until reset) - flush all internally delayed frames
//  returns: -1: error, 0: no output, 1: output available
int vf_output_frame(struct vf_chain *c, bool eof)
{
    return vf_output_frame_until(c, c->last, eof);
}

struct mp_image *vf_read_output_frame(struct vf_chain *c)
{
    if (!c->last->num_out_queued)
        vf_output_frame(c, false);
    return vf_dequeue_output_frame(c->last);
}

// Some filters (vf_vapoursynth) filter on separate threads, and may need new
// input from the decoder, even though the core does not need a new output image
// yet (this is required to get proper pipelining in the filter). If the filter
// needs new data, it will call c->wakeup_callback, which in turn causes the
// core to recheck the filter chain, calling this function. Each filter is asked
// whether it needs a frame (with vf->needs_input), and if so, it will try to
// feed it a new frame. If this fails, it will request a new frame from the
// core by returning 1.
// returns -1: error, 0: nothing needed, 1: add new frame with vf_filter_frame()
int vf_needs_input(struct vf_chain *c)
{
    struct vf_instance *prev = c->first;
    for (struct vf_instance *cur = c->first; cur; cur = cur->next) {
        while (cur->needs_input && cur->needs_input(cur)) {
            // Get frames from preceding filters, or if there are none,
            // request new frames from decoder.
            int r = vf_output_frame_until(c, prev, false);
            if (r < 1)
                return r < 0 ? -1 : 1;
            r = vf_do_filter(cur, vf_dequeue_output_frame(prev));
            if (r < 0)
                return r;
        }
        prev = cur;
    }
    return 0;
}

static void vf_forget_frames(struct vf_instance *vf)
{
    for (int n = 0; n < vf->num_out_queued; n++)
        talloc_free(vf->out_queued[n]);
    vf->num_out_queued = 0;
}

static void vf_chain_forget_frames(struct vf_chain *c)
{
    for (struct vf_instance *cur = c->first; cur; cur = cur->next)
        vf_forget_frames(cur);
}

void vf_seek_reset(struct vf_chain *c)
{
    vf_control_all(c, VFCTRL_SEEK_RESET, NULL);
    vf_chain_forget_frames(c);
}

int vf_next_config(struct vf_instance *vf,
                   int width, int height, int d_width, int d_height,
                   unsigned int voflags, unsigned int outfmt)
{
    vf->fmt_out = vf->fmt_in;
    vf->fmt_out.imgfmt = outfmt;
    vf->fmt_out.w = width;
    vf->fmt_out.h = height;
    vf->fmt_out.d_w = d_width;
    vf->fmt_out.d_h = d_height;
    return 1;
}

int vf_next_query_format(struct vf_instance *vf, unsigned int fmt)
{
    return fmt >= IMGFMT_START && fmt < IMGFMT_END
           ? vf->last_outfmts[fmt - IMGFMT_START] : 0;
}

// Mark accepted input formats in fmts[]. Note that ->query_format will
// typically (but not always) call vf_next_query_format() to check whether
// an output format is supported.
static void query_formats(uint8_t *fmts, struct vf_instance *vf)
{
    for (int n = IMGFMT_START; n < IMGFMT_END; n++)
        fmts[n - IMGFMT_START] = vf->query_format(vf, n);
}

static bool is_conv_filter(struct vf_instance *vf)
{
    return vf && strcmp(vf->info->name, "scale") == 0;
}

static void update_formats(struct vf_chain *c, struct vf_instance *vf,
                           uint8_t *fmts)
{
    if (vf->next)
        update_formats(c, vf->next, vf->last_outfmts);
    query_formats(fmts, vf);
    bool has_in = false, has_out = false;
    for (int n = IMGFMT_START; n < IMGFMT_END; n++) {
        has_in |= !!fmts[n - IMGFMT_START];
        has_out |= !!vf->last_outfmts[n - IMGFMT_START];
    }
    if (has_out && !has_in && !is_conv_filter(vf) &&
        !is_conv_filter(vf->next))
    {
        // If there are output formats, but no input formats (meaning the
        // filters after vf work, but vf can't output any format the filters
        // after it accept), try to insert a conversion filter.
        MP_INFO(c, "Using conversion filter.\n");
        struct vf_instance *conv = vf_open(c, "scale", NULL);
        if (conv) {
            conv->autoinserted = true;
            conv->next = vf->next;
            vf->next = conv;
            update_formats(c, conv, vf->last_outfmts);
            query_formats(fmts, vf);
        }
    }
    for (int n = IMGFMT_START; n < IMGFMT_END; n++)
        has_in |= !!fmts[n - IMGFMT_START];
    if (!has_in) {
        // Pretend all out formats work. All this does it getting better
        // error messages in some cases, so we can configure all filter
        // until it fails, which will be visible in vf_print_filter_chain().
        for (int n = IMGFMT_START; n < IMGFMT_END; n++)
            vf->last_outfmts[n - IMGFMT_START] = 1;
        query_formats(fmts, vf);
    }
}

static int vf_reconfig_wrapper(struct vf_instance *vf,
                               const struct mp_image_params *p)
{
    vf_forget_frames(vf);
    if (vf->out_pool)
        mp_image_pool_clear(vf->out_pool);

    if (!vf->query_format(vf, p->imgfmt))
        return -2;

    vf->fmt_out = vf->fmt_in = *p;

    if (!mp_image_params_valid(&vf->fmt_in))
        return -2;

    int r;
    if (vf->reconfig) {
        r = vf->reconfig(vf, &vf->fmt_in, &vf->fmt_out);
    } else if (vf->config) {
        r = vf->config(vf, p->w, p->h, p->d_w, p->d_h, 0, p->imgfmt) ? 0 : -1;
    } else {
        r = 0;
    }

    if (!mp_image_params_equal(&vf->fmt_in, p))
        r = -2;

    if (!mp_image_params_valid(&vf->fmt_out))
        r = -2;

    // Fix csp in case of pixel format change
    if (r >= 0)
        mp_image_params_guess_csp(&vf->fmt_out);

    return r;
}

// override_params is used to forcibly change the parameters of input images,
// while params has to match the input images exactly.
int vf_reconfig(struct vf_chain *c, const struct mp_image_params *params,
                const struct mp_image_params *override_params)
{
    int r = 0;
    vf_chain_forget_frames(c);
    for (struct vf_instance *vf = c->first; vf; ) {
        struct vf_instance *next = vf->next;
        if (vf->autoinserted)
            vf_remove_filter(c, vf);
        vf = next;
    }
    c->input_params = *params;
    c->first->fmt_in = *override_params;
    c->override_params = *override_params;
    struct mp_image_params cur = c->override_params;

    uint8_t unused[IMGFMT_END - IMGFMT_START];
    update_formats(c, c->first, unused);
    struct vf_instance *failing = NULL;
    for (struct vf_instance *vf = c->first; vf; vf = vf->next) {
        r = vf_reconfig_wrapper(vf, &cur);
        if (r < 0) {
            failing = vf;
            break;
        }
        cur = vf->fmt_out;
    }
    c->output_params = cur;
    c->initialized = r < 0 ? -1 : 1;
    int loglevel = r < 0 ? MSGL_WARN : MSGL_V;
    if (r == -2)
        MP_ERR(c, "Image formats incompatible or invalid.\n");
    mp_msg(c->log, loglevel, "Video filter chain:\n");
    vf_print_filter_chain(c, loglevel, failing);
    if (r < 0) {
        c->input_params = c->override_params = c->output_params =
            (struct mp_image_params){0};
    }
    return r;
}

struct vf_instance *vf_find_by_label(struct vf_chain *c, const char *label)
{
    struct vf_instance *vf = c->first;
    while (vf) {
        if (vf->label && label && strcmp(vf->label, label) == 0)
            return vf;
        vf = vf->next;
    }
    return NULL;
}

static void vf_uninit_filter(vf_instance_t *vf)
{
    if (vf->uninit)
        vf->uninit(vf);
    vf_forget_frames(vf);
    talloc_free(vf);
}

static int input_query_format(struct vf_instance *vf, unsigned int fmt)
{
    // Setting fmt_in is guaranteed by vf_reconfig().
    if (fmt == vf->fmt_in.imgfmt)
        return vf_next_query_format(vf, fmt);
    return 0;
}

static int output_query_format(struct vf_instance *vf, unsigned int fmt)
{
    struct vf_chain *c = (void *)vf->priv;
    if (fmt >= IMGFMT_START && fmt < IMGFMT_END)
        return c->allowed_output_formats[fmt - IMGFMT_START];
    return 0;
}

struct vf_chain *vf_new(struct mpv_global *global)
{
    struct vf_chain *c = talloc_ptrtype(NULL, c);
    *c = (struct vf_chain){
        .opts = global->opts,
        .log = mp_log_new(c, global->log, "!vf"),
        .global = global,
    };
    static const struct vf_info in = { .name = "in" };
    c->first = talloc(c, struct vf_instance);
    *c->first = (struct vf_instance) {
        .info = &in,
        .query_format = input_query_format,
    };
    static const struct vf_info out = { .name = "out" };
    c->last = talloc(c, struct vf_instance);
    *c->last = (struct vf_instance) {
        .info = &out,
        .query_format = output_query_format,
        .priv = (void *)c,
    };
    c->first->next = c->last;
    return c;
}

void vf_destroy(struct vf_chain *c)
{
    if (!c)
        return;
    while (c->first) {
        vf_instance_t *vf = c->first;
        c->first = vf->next;
        vf_uninit_filter(vf);
    }
    vf_chain_forget_frames(c);
    talloc_free(c);
}

// When changing the size of an image that had old_w/old_h with
// DAR *d_width/*d_height to the new size new_w/new_h, adjust
// *d_width/*d_height such that the new image has the same pixel aspect ratio.
void vf_rescale_dsize(int *d_width, int *d_height, int old_w, int old_h,
                      int new_w, int new_h)
{
    *d_width  = *d_width  * new_w / old_w;
    *d_height = *d_height * new_h / old_h;
}

// Set *d_width/*d_height to display aspect ratio with the givem source size
void vf_set_dar(int *d_w, int *d_h, int w, int h, double dar)
{
    *d_w = w;
    *d_h = h;
    if (dar > 0.01) {
        *d_w = h * dar + 0.5;
        // we don't like horizontal downscale
        if (*d_w < w) {
            *d_w = w;
            *d_h = w / dar + 0.5;
        }
    }
}