/*  RetroArch - A frontend for libretro.
 *  Copyright (C) 2018      - Stuart Carnie
 *
 *  RetroArch 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 Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  RetroArch 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 RetroArch.
 *  If not, see <http://www.gnu.org/licenses/>.
 */

#import <Metal/Metal.h>
#import <MetalKit/MetalKit.h>

#include <stdio.h>
#include <stdint.h>
#include <math.h>
#include <string.h>

#include <compat/strl.h>
#include <gfx/scaler/scaler.h>
#include <gfx/video_frame.h>
#include <formats/image.h>
#include <retro_inline.h>
#include <retro_miscellaneous.h>
#include <retro_math.h>
#include <retro_assert.h>
#include <libretro.h>

#ifdef HAVE_CONFIG_H
#import "../../config.h"
#endif

#ifdef HAVE_MENU
#import "../../menu/menu_driver.h"
#endif
#ifdef HAVE_GFX_WIDGETS
#import "../gfx_widgets.h"
#endif

#import "../font_driver.h"

#import "../common/metal_common.h"

#import "../../driver.h"
#import "../../configuration.h"

#import "../../retroarch.h"
#import "../../verbosity.h"

#import "../video_coord_array.h"

#include "../../ui/drivers/cocoa/apple_platform.h"

static uint32_t metal_get_flags(void *data);

#pragma mark Graphics Context for Metal

// The graphics context for the Metal driver is just a stubbed out version
// It supports getting metrics such as dpi which is needed for iOS/tvOS
#if defined(HAVE_COCOATOUCH)
static bool metal_gfx_ctx_get_metrics(void *data, enum display_metric_types type,
            float *value)
{
    CGRect screenRect = [[UIScreen mainScreen] bounds];
    CGFloat scale = [[UIScreen mainScreen] scale];
    float   displayHeight        = screenRect.size.height;
    float   physicalWidth        = screenRect.size.width  * scale;
    float   physicalHeight       = screenRect.size.height * scale;
    float   dpi                  = 160                     * scale;
    CGFloat maxSize              = fmaxf(physicalWidth, physicalHeight);
    NSInteger idiom_type         = UI_USER_INTERFACE_IDIOM();
    switch (idiom_type)
    {
       case -1:
          break;
       case UIUserInterfaceIdiomPad:
          dpi = 132 * scale;
          break;
       case UIUserInterfaceIdiomPhone:
            if (maxSize >= 2208.0) {
                // Larger iPhones: iPhone Plus, X, XR, XS, XS Max, 11, 11 Pro Max
                dpi = 81 * scale;
            } else {
                dpi = 163 * scale;
            }
          break;
       case UIUserInterfaceIdiomTV:
       case UIUserInterfaceIdiomCarPlay:
          /* TODO */
          break;
    }
    (void)displayHeight;

    switch (type)
    {
        case DISPLAY_METRIC_MM_WIDTH:
            *value = physicalWidth;
            break;
        case DISPLAY_METRIC_MM_HEIGHT:
            *value = physicalHeight;
            break;
        case DISPLAY_METRIC_DPI:
            *value = dpi;
            break;
        case DISPLAY_METRIC_NONE:
        default:
            *value = 0;
            return false;
    }
    return true;
}
#endif

/* Temporary workaround for metal not being able to poll flags during init */
static gfx_ctx_driver_t metal_fake_context = {
       NULL,
       NULL,
       NULL,
       NULL,
       NULL,
       NULL,
       NULL,
       NULL, /* get_refresh_rate */
       NULL, /* get_video_output_size */
       NULL, /* get_video_output_prev */
       NULL, /* get_video_output_next */
#ifdef HAVE_COCOATOUCH
       metal_gfx_ctx_get_metrics,
#else
       NULL,
#endif
       NULL, /* translate_aspect */
       NULL, /* update_title */
       NULL,
       NULL, /* set_resize */
       NULL,
       NULL,
       false,
       NULL,
       NULL,
       NULL,
       NULL, /* image_buffer_init */
       NULL, /* image_buffer_write */
       NULL, /* show_mouse */
       "metal",
       NULL,
       NULL,
       NULL,
       NULL, /* get_context_data */
       NULL  /* make_current */
};

static bool metal_set_shader(void *data,
      enum rarch_shader_type type, const char *path);

static void *metal_init(
      const video_info_t *video,
      input_driver_t **input,
      void **input_data)
{
   const char *shader_path;
   enum rarch_shader_type type;
   MetalDriver *md = nil;

   [apple_platform setViewType:APPLE_VIEW_TYPE_METAL];

   md = [[MetalDriver alloc] initWithVideo:video input:input inputData:input_data];
   if (md == nil)
      return NULL;

   metal_fake_context.get_flags = metal_get_flags;
   video_context_driver_set(&metal_fake_context);

   shader_path = retroarch_get_shader_preset();
   type = video_shader_parse_type(shader_path);
   metal_set_shader((__bridge void *)md, type, shader_path);

   return (__bridge_retained void *)md;
}

static bool metal_frame(void *data, const void *frame,
      unsigned frame_width, unsigned frame_height,
      uint64_t frame_count,
      unsigned pitch, const char *msg,
      video_frame_info_t *video_info)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   return [md renderFrame:frame
                     data:data
                    width:frame_width
                   height:frame_height
               frameCount:frame_count
                    pitch:pitch
                      msg:msg
                     info:video_info];
}

static void metal_set_nonblock_state(void *data, bool non_block,
      bool adaptive_vsync_enabled, unsigned swap_interval)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   md.context.displaySyncEnabled = !non_block;
}

static bool metal_alive(void *data) { return true; }
static bool metal_has_windowed(void *data) { return true; }
static bool metal_focus(void *data) { return apple_platform.hasFocus; }

static bool metal_suppress_screensaver(void *data, bool disable)
{
   return [apple_platform setDisableDisplaySleep:disable];
}

static bool metal_set_shader(void *data,
                             enum rarch_shader_type type, const char *path)
{
#if defined(HAVE_SLANG) && defined(HAVE_SPIRV_CROSS)
   MetalDriver *md = (__bridge MetalDriver *)data;

   if (!md)
      return false;

   if (type != RARCH_SHADER_SLANG)
   {
      if (!string_is_empty(path) && type != RARCH_SHADER_SLANG)
         RARCH_WARN("[Metal] Only Slang shaders are supported. Falling back to stock.\n");
      path = NULL;
   }

   /* TODO actually return to stock */
   if (string_is_empty(path))
      return true;

   return [md.frameView setShaderFromPath:[NSString stringWithUTF8String:path]];
#else
   return false;
#endif
}

static void metal_free(void *data)
{
   MetalDriver *md = (__bridge_transfer MetalDriver *)data;
   md = nil;
}

static void metal_set_viewport(void *data, unsigned viewport_width,
                               unsigned viewport_height, bool force_full, bool allow_rotate)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   if (md == nil) {
      return;
   }

   [md setViewportWidth:viewport_width height:viewport_height forceFull:force_full allowRotate:allow_rotate];
}

static void metal_set_rotation(void *data, unsigned rotation)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   if (md == nil) {
      return;
   }

   [md setRotation:rotation];
}

static void metal_viewport_info(void *data, struct video_viewport *vp)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   *vp = *md.viewport;
}

static bool metal_read_viewport(void *data, uint8_t *buffer, bool is_idle)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   return [md.frameView readViewport:buffer isIdle:is_idle];
}

static uintptr_t metal_load_texture(void *video_data, void *data,
                                    bool threaded, enum texture_filter_type filter_type)
{
   MetalDriver *md = (__bridge MetalDriver *)video_data;
   struct texture_image *img = (struct texture_image *)data;
   if (!img)
      return 0;

   struct texture_image image = *img;
   Texture *t = [md.context newTexture:image filter:filter_type];
   return (uintptr_t)(__bridge_retained void *)(t);
}

static void metal_unload_texture(void *data, 
      bool threaded, uintptr_t handle)
{
   if (!handle)
      return;
   Texture *t = (__bridge_transfer Texture *)(void *)handle;
   t = nil;
}

static void metal_set_video_mode(void *data,
                                 unsigned width, unsigned height,
                                 bool fullscreen)
{
   RARCH_LOG("[Metal]: set_video_mode res=%dx%d fullscreen=%s\n",
             width, height,
             fullscreen ? "YES" : "NO");
}

static float metal_get_refresh_rate(void *data)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   (void)md;

   return 0.0f;
}

static void metal_set_filtering(void *data, unsigned index, bool smooth, bool ctx_scaling)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   [md.frameView setFilteringIndex:index smooth:smooth];
}

static void metal_set_aspect_ratio(void *data, unsigned aspect_ratio_idx)
{
   MetalDriver *md = (__bridge MetalDriver *)data;

   md.keepAspect = YES;
   [md setNeedsResize];
}

static void metal_apply_state_changes(void *data)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   [md setNeedsResize];
}

static void metal_set_texture_frame(void *data, const void *frame,
      bool rgb32, unsigned width, unsigned height,
      float alpha)
{
   MetalDriver *md         = (__bridge MetalDriver *)data;
   settings_t *settings    = config_get_ptr();
   bool menu_linear_filter = settings->bools.menu_linear_filter;

   [md.menu updateWidth:width
                 height:height
                 format:rgb32 ? RPixelFormatBGRA8Unorm : RPixelFormatBGRA4Unorm
                 filter:menu_linear_filter ? RTextureFilterLinear : RTextureFilterNearest];
   [md.menu updateFrame:frame];
   md.menu.alpha = alpha;
}

static void metal_set_texture_enable(void *data, bool state, bool full_screen)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   if (!md)
      return;

   md.menu.enabled = state;
#if 0
   md.menu.fullScreen = full_screen;
#endif
}

static void metal_show_mouse(void *data, bool state)
{
   [apple_platform setCursorVisible:state];
}

static struct video_shader *metal_get_current_shader(void *data)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   if (!md)
      return NULL;

   return md.frameView.shader;
}

static uint32_t metal_get_flags(void *data)
{
   uint32_t flags = 0;

   BIT32_SET(flags, GFX_CTX_FLAGS_CUSTOMIZABLE_SWAPCHAIN_IMAGES);
   BIT32_SET(flags, GFX_CTX_FLAGS_BLACK_FRAME_INSERTION);
   BIT32_SET(flags, GFX_CTX_FLAGS_MENU_FRAME_FILTERING);
   BIT32_SET(flags, GFX_CTX_FLAGS_SCREENSHOTS_SUPPORTED);

#if defined(HAVE_SLANG) && defined(HAVE_SPIRV_CROSS)
   BIT32_SET(flags, GFX_CTX_FLAGS_SHADERS_SLANG);
#endif

   return flags;
}

static const video_poke_interface_t metal_poke_interface = {
   metal_get_flags,
   metal_load_texture,
   metal_unload_texture,
   metal_set_video_mode,
   metal_get_refresh_rate,
   metal_set_filtering,
   NULL,                      /* get_video_output_size */
   NULL,                      /* get_video_output_prev */
   NULL,                      /* get_video_output_next */
   NULL,                      /* get_current_framebuffer */
   NULL,                      /* get_proc_address */
   metal_set_aspect_ratio,
   metal_apply_state_changes,
   metal_set_texture_frame,
   metal_set_texture_enable,
   font_driver_render_msg,
   metal_show_mouse,
   NULL,                      /* grab_mouse_toggle */
   metal_get_current_shader,
   NULL,                      /* get_current_software_framebuffer */
   NULL,                      /* get_hw_render_interface */
   NULL,                      /* set_hdr_max_nits */
   NULL,                      /* set_hdr_paper_white_nits */
   NULL,                      /* set_hdr_contrast */
   NULL                       /* set_hdr_expand_gamut */
};

static void metal_get_poke_interface(void *data,
      const video_poke_interface_t **iface)
{
   (void)data;
   *iface = &metal_poke_interface;
}

#ifdef HAVE_OVERLAY

static void metal_overlay_enable(void *data, bool state)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   if (!md)
      return;
   md.overlay.enabled = state;
}

static bool metal_overlay_load(void *data,
      const void *images, unsigned num_images)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   if (!md)
      return NO;

   return [md.overlay loadImages:(const struct texture_image *)images count:num_images];
}

static void metal_overlay_tex_geom(void *data, unsigned index,
      float x, float y, float w, float h)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   if (!md)
      return;

   [md.overlay updateTextureCoordsX:x y:y w:w h:h index:index];
}

static void metal_overlay_vertex_geom(void *data, unsigned index,
      float x, float y, float w, float h)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   if (!md)
      return;

   [md.overlay updateVertexX:x y:y w:w h:h index:index];
}

static void metal_overlay_full_screen(void *data, bool enable)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   if (!md)
      return;

   md.overlay.fullscreen = enable;
}

static void metal_overlay_set_alpha(void *data, unsigned index, float mod)
{
   MetalDriver *md = (__bridge MetalDriver *)data;
   if (!md)
      return;

   [md.overlay updateAlpha:mod index:index];
}

static const video_overlay_interface_t metal_overlay_interface = {
   .enable        = metal_overlay_enable,
   .load          = metal_overlay_load,
   .tex_geom      = metal_overlay_tex_geom,
   .vertex_geom   = metal_overlay_vertex_geom,
   .full_screen   = metal_overlay_full_screen,
   .set_alpha     = metal_overlay_set_alpha,
};

static void metal_get_overlay_interface(void *data,
      const video_overlay_interface_t **iface)
{
   (void)data;
   *iface = &metal_overlay_interface;
}

#endif

#ifdef HAVE_GFX_WIDGETS
static bool metal_gfx_widgets_enabled(void *data)
{
   (void)data;
   return true;
}
#endif

video_driver_t video_metal = {
   metal_init,
   metal_frame,
   metal_set_nonblock_state,
   metal_alive,
   metal_focus,
   metal_suppress_screensaver,
   metal_has_windowed,
   metal_set_shader,
   metal_free,
   "metal",
   metal_set_viewport,
   metal_set_rotation,
   metal_viewport_info,
   metal_read_viewport,
   NULL, /* read_frame_raw */
#ifdef HAVE_OVERLAY
   metal_get_overlay_interface,
#endif
#ifdef HAVE_VIDEO_LAYOUT
  NULL,
#endif
   metal_get_poke_interface,
   NULL, /* metal_wrap_type_to_enum */
#ifdef HAVE_GFX_WIDGETS
   metal_gfx_widgets_enabled
#endif
};