/*

 * 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 "win_state.h"

#include "vo.h"

#include "video/mp_image.h"

static void calc_monitor_aspect(struct mp_vo_opts *opts, int scr_w, int scr_h,

                                double *pixelaspect, int *w, int *h)

{

    *pixelaspect = 1.0 / opts->monitor_pixel_aspect;

    if (scr_w > 0 && scr_h > 0 && opts->force_monitor_aspect)

        *pixelaspect = 1.0 / (opts->force_monitor_aspect * scr_h / scr_w);

    if (*pixelaspect < 1) {

        *h /= *pixelaspect;

    } else {

        *w *= *pixelaspect;

    }

}

// Fit *w/*h into the size specified by geo.

static void apply_autofit(int *w, int *h, int scr_w, int scr_h,

                          struct m_geometry *geo, bool allow_up, bool allow_down)

{

    if (!geo->wh_valid)

        return;

    int dummy = 0;

    int n_w = *w, n_h = *h;

    m_geometry_apply(&dummy, &dummy, &n_w, &n_h, scr_w, scr_h, true, geo);

    if (!allow_up && *w <= n_w && *h <= n_h)

        return;

    if (!allow_down && *w >= n_w && *h >= n_h)

        return;

    // If aspect mismatches, always make the window smaller than the fit box

    // (Or larger, if allow_down==false.)

    double asp = (double)*w / *h;

    double n_asp = (double)n_w / n_h;

    if ((n_asp <= asp) == allow_down) {

        *w = n_w;

        *h = MPMAX(n_w / asp, 1);

    } else {

        *w = MPMAX(n_h * asp, 1);

        *h = n_h;

    }

}

// Compute the "suggested" window size and position and return it in *out_geo.

// screen is the bounding box of the current screen within the virtual desktop.

// Does not change *vo.

//  screen: position of the area on virtual desktop on which the video-content

//          should be placed (maybe after excluding decorations, taskbars, etc)

//          can be the same as monitor for platforms that don't try to take into

//          account decorations, taskbars, etc.

//  monitor: position of the monitor on virtual desktop (used for pixelaspect).

//  dpi_scale: the DPI multiplier to get from virtual to real coordinates

//             (>1 for "hidpi")

//  force_pos: force window position even if opts->force_window_position is not

//             set. If geometry x/y is not valid, this will center the window.

//             Useful for initial window placement.

//  size_constraint: if non-NULL, the resulting size will be limited by the size

//                   specified in this geometry. This applies to both autofit

//                   and geometry options.

// Use vo_apply_window_geometry() to copy the result into the vo.

// NOTE: currently, all windowing backends do their own handling of window

//       geometry additional to this code. This is to deal with initial window

//       placement, fullscreen handling, avoiding resize on reconfig() with no

//       size change, multi-monitor stuff, and possibly more.

void vo_calc_window_geometry(struct vo *vo, struct mp_vo_opts *opts,

                             const struct mp_rect *screen,

                             const struct mp_rect *monitor, double dpi_scale,

                             bool force_pos, struct vo_win_geometry *out_geo,

                             struct m_geometry *size_constraint)

{

    *out_geo = (struct vo_win_geometry){0};

    // The case of calling this function even though no video was configured

    // yet (i.e. vo->params==NULL) happens when vo_gpu creates a hidden window

    // in order to create a rendering context.

    struct mp_image_params params = { .w = 320, .h = 200 };

    if (vo->params)

        params = *vo->params;

    if (!opts->hidpi_window_scale)

        dpi_scale = 1;

    int d_w, d_h;

    mp_image_params_get_dsize(&params, &d_w, &d_h);

    if ((vo->driver->caps & VO_CAP_ROTATE90) && params.rotate % 180 == 90)

        MPSWAP(int, d_w, d_h);

    d_w = MPCLAMP(d_w * opts->window_scale * dpi_scale, 1, 16000);

    d_h = MPCLAMP(d_h * opts->window_scale * dpi_scale, 1, 16000);

    int scr_w = screen->x1 - screen->x0;

    int scr_h = screen->y1 - screen->y0;

    int mon_w = monitor->x1 - monitor->x0;

    int mon_h = monitor->y1 - monitor->y0;

    MP_DBG(vo, "max content size: %dx%d\n", scr_w, scr_h);

    MP_DBG(vo, "monitor size: %dx%d\n", mon_w, mon_h);

    calc_monitor_aspect(opts, mon_w, mon_h, &out_geo->monitor_par, &d_w, &d_h);

    apply_autofit(&d_w, &d_h, scr_w, scr_h, &opts->autofit, true, true);

    apply_autofit(&d_w, &d_h, scr_w, scr_h, &opts->autofit_smaller, true, false);

    apply_autofit(&d_w, &d_h, scr_w, scr_h, &opts->autofit_larger, false, true);

    if (size_constraint)

        apply_autofit(&d_w, &d_h, scr_w, scr_h, size_constraint, false, true);

    out_geo->win.x0 = (int)(scr_w - d_w) / 2;

    out_geo->win.y0 = (int)(scr_h - d_h) / 2;

    bool center = (opts->force_window_position || force_pos) && !opts->geometry.xy_valid;

    m_geometry_apply(&out_geo->win.x0, &out_geo->win.y0, &d_w, &d_h,

                     scr_w, scr_h, center, &opts->geometry);

    if (size_constraint) {

        int old_w = d_w, old_h = d_h;

        apply_autofit(&d_w, &d_h, scr_w, scr_h, size_constraint, false, true);

        if (!opts->geometry.xy_valid) {

            out_geo->win.x0 += (old_w - d_w) / 2;

            out_geo->win.y0 += (old_h - d_h) / 2;

        }

    }

    out_geo->win.x0 += screen->x0;

    out_geo->win.y0 += screen->y0;

    out_geo->win.x1 = out_geo->win.x0 + d_w;

    out_geo->win.y1 = out_geo->win.y0 + d_h;

    if (opts->force_window_position || force_pos)

        out_geo->flags |= VO_WIN_FORCE_POS;

}

// Copy the parameters in *geo to the vo fields.

// (Doesn't do anything else - windowing backends should trigger VO_EVENT_RESIZE

//  to ensure that the VO reinitializes rendering properly.)

void vo_apply_window_geometry(struct vo *vo, const struct vo_win_geometry *geo)

{

    vo->dwidth = geo->win.x1 - geo->win.x0;

    vo->dheight = geo->win.y1 - geo->win.y0;

    vo->monitor_par = geo->monitor_par;

}