/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <fcntl.h>
#include <stdio.h>

#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/types.h>

#include <linux/fb.h>
#include <linux/kd.h>

#include <time.h>

#include "font_10x18.h"
#include "minui.h"
#include "graphics.h"
#include "common.h"

typedef struct {
    GRSurface* texture;
    int char_width;
    int char_height;
} GRFont;

extern minui_backend* open_drm();

static GRFont* gr_font = NULL;
static minui_backend* gr_backend = NULL;

static int overscan_percent = 0;
static int overscan_offset_x = 0;
static int overscan_offset_y = 0;

static int gr_vt_fd = -1;

static uint32_t gr_current = ~0;
static uint32_t alpha_mask = 0xff000000;
static GRRotation rotation = ROTATION_NONE;

GRSurface* gr_draw = NULL;
extern minui_backend* open_drm();

//static bool outside(int x, int y)
//{
//    return x < 0 || x >= gr_draw->width || y < 0 || y >= gr_draw->height;
//}

static bool outside(int x, int y) {
  return x < 0 || x >= (rotation % 2 ? gr_draw->height : gr_draw->width) || y < 0 ||
         y >= (rotation % 2 ? gr_draw->width : gr_draw->height);
}

int gr_measure(const char *s)
{
    return gr_font->char_width * strlen(s);
}

void gr_font_size(int *x, int *y)
{
    *x = gr_font->char_width;
    *y = gr_font->char_height;
}

// Blends gr_current onto pix value, assumes alpha as most significant byte.
static inline uint32_t pixel_blend(uint8_t alpha, uint32_t pix) {
  if (alpha == 255) return gr_current;
  if (alpha == 0) return pix;
  uint32_t pix_r = pix & 0xff;
  uint32_t pix_g = pix & 0xff00;
  uint32_t pix_b = pix & 0xff0000;
  uint32_t cur_r = gr_current & 0xff;
  uint32_t cur_g = gr_current & 0xff00;
  uint32_t cur_b = gr_current & 0xff0000;

  uint32_t out_r = (pix_r * (255 - alpha) + cur_r * alpha) / 255;
  uint32_t out_g = (pix_g * (255 - alpha) + cur_g * alpha) / 255;
  uint32_t out_b = (pix_b * (255 - alpha) + cur_b * alpha) / 255;

  return (out_r & 0xff) | (out_g & 0xff00) | (out_b & 0xff0000) | (gr_current & 0xff000000);
}

// increments pixel pointer right, with current rotation.
static void incr_x(uint32_t** p, int row_pixels) {
    if (rotation % 2) {
        *p = *p + (rotation == 1 ? 1 : -1) * row_pixels;
        } else {
            *p = *p + (rotation ? -1 : 1);
    }
}

// increments pixel pointer down, with current rotation.
static void incr_y(uint32_t** p, int row_pixels) {
    if (rotation % 2) {
        *p = *p + (rotation == 1 ? -1 : 1);
    } else {
        *p = *p + (rotation ? -1 : 1) * row_pixels;
    }
}

// returns pixel pointer at given coordinates with rotation adjustment.
static uint32_t* pixel_at(GRSurface* surf, int x, int y, int row_pixels) {
    switch (rotation) {
        case ROTATION_NONE:
            return (uint32_t*)(surf->data) + y * row_pixels + x;
        case ROTATION_RIGHT:
            return (uint32_t*)(surf->data) + x * row_pixels + (surf->width - y);
        case ROTATION_DOWN:
            return (uint32_t*)(surf->data) + (surf->height - 1 - y) * row_pixels +
                    (surf->width - 1 - x);
        case ROTATION_LEFT:
            return (uint32_t*)(surf->data) + (surf->height - 1 - x) * row_pixels + y;
        default:
            printf("invalid rotation %d", rotation);
    }
    return NULL;
}


static void text_blend(unsigned char* src_p, int src_row_bytes,
                       uint32_t* dst_p, int dst_row_pixels,
                       int width, int height)
{
    uint8_t alpha_current = (uint8_t)((alpha_mask & gr_current) >> 24);
    for (int j = 0; j < height; ++j) {
        uint8_t* sx = src_p;
        uint32_t* px = dst_p;
        for (int i = 0; i < width; ++i, incr_x(&px, dst_row_pixels)) {
              uint8_t a = *sx++;
              if (alpha_current < 255) a = ((uint32_t)(a) * alpha_current) / 255;
              *px = pixel_blend(a, *px);
        }
        src_p += src_row_bytes;
        incr_y(&dst_p, dst_row_pixels);
    }
}


void gr_text(int x, int y, const char *s)
{
    GRFont *font = gr_font;
    unsigned off;
    int bold = 0;

    if (!font || !font->texture || (gr_current & alpha_mask) == 0) return;

    if (font->texture->pixel_bytes != 1) {
        printf("gr_text: font has wrong format\n");
        return;
    }

    bold = bold && (font->texture->height != font->char_height);

    x += overscan_offset_x;
    y += overscan_offset_y;

    unsigned char ch;
    while((ch = *s++)) {
        if (outside(x, y) || outside(x + font->char_width - 1, y + font->char_height - 1)) break;

        if (ch < ' ' || ch > '~') {
            ch = '?';
        }

    if(!gr_draw) return;
    int row_pixels = gr_draw->row_bytes / gr_draw->pixel_bytes;
    uint8_t* src_p = font->texture->data + ((ch - ' ') * font->char_width) +
                     (bold ? font->char_height * font->texture->row_bytes : 0);
    uint32_t* dst_p = pixel_at(gr_draw, x, y, row_pixels);

    text_blend(src_p, font->texture->row_bytes, dst_p, row_pixels, font->char_width,
               font->char_height);
        x += font->char_width;
    }
}

void gr_texticon(int x, int y, GRSurface* icon) {
    if (icon == NULL) return;

    if (icon->pixel_bytes != 1) {
        printf("gr_texticon: source has wrong format\n");
        return;
    }

    x += overscan_offset_x;
    y += overscan_offset_y;

    if (outside(x, y) || outside(x+icon->width-1, y+icon->height-1)) return;

    if(!gr_draw) return;
    int row_pixels = gr_draw->row_bytes / gr_draw->pixel_bytes;
    uint8_t* src_p = icon->data;
    uint32_t* dst_p = pixel_at(gr_draw, x, y, row_pixels);

    text_blend(src_p, icon->row_bytes,dst_p, row_pixels, icon->width, icon->height);
}

void gr_color(unsigned char r, unsigned char g, unsigned char b, unsigned char a)
{
    uint32_t r32 = r, g32 = g, b32 = b, a32 = a;
#if defined(RECOVERY_ABGR) || defined(RECOVERY_BGRA)
    gr_current = (a32 << 24) | (r32 << 16) | (g32 << 8) | b32;
#else
    gr_current = (a32 << 24) | (b32 << 16) | (g32 << 8) | r32;
#endif

}

void gr_clear()
{
    if(!gr_draw) return;
    if ((gr_current & 0xff) == ((gr_current >> 8) & 0xff) &&
      (gr_current & 0xff) == ((gr_current >> 16) & 0xff) &&
      (gr_current & 0xff) == ((gr_current >> 24) & 0xff) &&
      gr_draw->row_bytes == gr_draw->width * gr_draw->pixel_bytes) {
        memset(gr_draw->data, gr_current & 0xff, gr_draw->height * gr_draw->row_bytes);
    } else {
        int x, y;
        uint32_t* px = (uint32_t*)(gr_draw->data);
        int row_diff = gr_draw->row_bytes / gr_draw->pixel_bytes - gr_draw->width;
        for (y = 0; y < gr_draw->height; ++y) {
            for (x = 0; x < gr_draw->width; ++x) {
                *px++ = gr_current;
            }
            px += row_diff;
        }
    }
}

void gr_fill(int x1, int y1, int x2, int y2)
{
    if(!gr_draw)
        return;

    x1 += overscan_offset_x;
    y1 += overscan_offset_y;

    x2 += overscan_offset_x;
    y2 += overscan_offset_y;

    if (outside(x1, y1) || outside(x2 - 1, y2 - 1)) return;

    int row_pixels = gr_draw->row_bytes / gr_draw->pixel_bytes;
    uint32_t* p = pixel_at(gr_draw, x1, y1, row_pixels);
    uint8_t alpha = (uint8_t)(((gr_current & alpha_mask) >> 24));
    if (alpha > 0) {
        for (int y = y1; y < y2; ++y) {
            uint32_t* px = p;
            for (int x = x1; x < x2 - 1; ++x) {
                *px = pixel_blend(alpha, *px);
                //printf("%d \n", x);
                incr_x(&px, row_pixels);
                //printf("%d ", x);
            }
            incr_y(&p, row_pixels);
            //printf("%d \n", y);
        }
    }
}

void gr_blit(gr_surface source, int sx, int sy, int w, int h, int dx, int dy)
{
    if (source == NULL) return;

    if (gr_draw->pixel_bytes != source->pixel_bytes) {
        printf("gr_blit: source has wrong format\n");
        return;
    }

    dx += overscan_offset_x;
    dy += overscan_offset_y;

    if (outside(dx, dy) || outside(dx+w-1, dy+h-1)) return;

    if (rotation) {
        int src_row_pixels = source->row_bytes / source->pixel_bytes;
        int row_pixels = gr_draw->row_bytes / gr_draw->pixel_bytes;
        uint32_t* src_py = (uint32_t*)(source->data) + sy * source->row_bytes / 4 + sx;
        uint32_t* dst_py = pixel_at(gr_draw, dx, dy, row_pixels);

        for (int y = 0; y < h; y += 1) {
            uint32_t* src_px = src_py;
            uint32_t* dst_px = dst_py;
            for (int x = 0; x < w; x += 1) {
                *dst_px = *src_px++;
                incr_x(&dst_px, row_pixels);
            }
            src_py += src_row_pixels;
            incr_y(&dst_py, row_pixels);
        }
    } else {
        unsigned char* src_p = source->data + sy*source->row_bytes + sx*source->pixel_bytes;
        unsigned char* dst_p = gr_draw->data + dy*gr_draw->row_bytes + dx*gr_draw->pixel_bytes;

        int i;
        for (i = 0; i < h; ++i) {
            memcpy(dst_p, src_p, w * source->pixel_bytes);
            src_p += source->row_bytes;
            dst_p += gr_draw->row_bytes;
        }
    }
}

unsigned int gr_get_width(GRSurface* surface)
{
    if (surface == NULL) {
        return 0;
    }
    return surface->width;
}

unsigned int gr_get_height(GRSurface* surface)
{
    if (surface == NULL) {
        return 0;
    }
    return surface->height;
}

static void gr_init_font(void)
{
    gr_font = calloc(sizeof(*gr_font), 1);

    int res = res_create_alpha_surface("font", &(gr_font->texture));
    if (res == 0) {
        // The font image should be a 96x2 array of character images.  The
        // columns are the printable ASCII characters 0x20 - 0x7f.  The
        // top row is regular text; the bottom row is bold.
        gr_font->char_width = gr_font->texture->width / 96;
        gr_font->char_height = gr_font->texture->height / 2;
    } else {
        printf("failed to read font: res=%d, fall back to the compiled-in font\n", res);

        // fall back to the compiled-in font.
        gr_font->texture = malloc(sizeof(*gr_font->texture));
        gr_font->texture->width = font.width;
        gr_font->texture->height = font.height;
        gr_font->texture->row_bytes = font.width;
        gr_font->texture->pixel_bytes = 1;

        unsigned char* bits = malloc(font.width * font.height);
        gr_font->texture->data = (void*) bits;

        unsigned char data;
        unsigned char* in = font.rundata;
        while((data = *in++)) {
            memset(bits, (data & 0x80) ? 255 : 0, data & 0x7f);
            bits += (data & 0x7f);
        }

        gr_font->char_width = font.char_width;
        gr_font->char_height = font.char_height;
    }
}

#if 0
// Exercises many of the gr_*() functions; useful for testing.
static void gr_test() {
    GRSurface** images;
    int frames;
    int result = res_create_multi_surface("icon_installing", &frames, &images);
    if (result < 0) {
        printf("create surface %d\n", result);
        gr_exit();
        return;
    }

    time_t start = time(NULL);
    int x;
    for (x = 0; x <= 1200; ++x) {
        if (x < 400) {
            gr_color(0, 0, 0, 255);
        } else {
            gr_color(0, (x-400)%128, 0, 255);
        }
        gr_clear();

        gr_color(255, 0, 0, 255);
        gr_surface frame = images[x%frames];
        gr_blit(frame, 0, 0, frame->width, frame->height, x, 0);

        gr_color(255, 0, 0, 128);
        gr_fill(400, 150, 600, 350);

        gr_color(255, 255, 255, 255);
        gr_text(500, 225, "hello, world!", 0);
        gr_color(255, 255, 0, 128);
        gr_text(300+x, 275, "pack my box with five dozen liquor jugs", 1);

        gr_color(0, 0, 255, 128);
        gr_fill(gr_draw->width - 200 - x, 300, gr_draw->width - x, 500);

        gr_draw = gr_backend->flip(gr_backend);
    }
    printf("getting end time\n");
    time_t end = time(NULL);
    printf("got end time\n");
    printf("start %ld end %ld\n", (long)start, (long)end);
    if (end > start) {
        printf("%.2f fps\n", ((double)x) / (end-start));
    }
}
#endif

void gr_flip() {
    if(!gr_draw) return;
    gr_draw = gr_backend->flip(gr_backend);
}

int gr_init(void)
{
    gr_init_font();

    gr_vt_fd = open("/dev/tty0", O_RDWR | O_SYNC);
    if (gr_vt_fd < 0) {
        // This is non-fatal; post-Cupcake kernels don't have tty0.
        perror("can't open /dev/tty0");
    } else if (ioctl(gr_vt_fd, KDSETMODE, (void*) KD_GRAPHICS)) {
        // However, if we do open tty0, we expect the ioctl to work.
        perror("failed KDSETMODE to KD_GRAPHICS on tty0");
        gr_exit();
        return -1;
    }

    gr_backend = 0;//open_adf();
    if (gr_backend) {
        gr_draw = gr_backend->init(gr_backend);
        if (!gr_draw) {
            gr_backend->exit(gr_backend);
        }
    }

    if (!gr_draw) {
        gr_backend = open_drm();
        gr_draw = gr_backend->init(gr_backend);
        if (gr_draw == NULL)
            return -1;
    }
#if 0
    if (!gr_draw) {
        gr_backend = open_fbdev();
        gr_draw = gr_backend->init(gr_backend);
        if (gr_draw == NULL) {
            return -1;
        }
    }
#endif

    overscan_offset_x = gr_draw->width * overscan_percent / 100;
    overscan_offset_y = gr_draw->height * overscan_percent / 100;

    gr_flip();

    gr_rotate(ROTATION_NONE);
    return 0;
}

void gr_exit(void)
{
    gr_backend->exit(gr_backend);

    ioctl(gr_vt_fd, KDSETMODE, (void*) KD_TEXT);
    close(gr_vt_fd);
    gr_vt_fd = -1;
}

//int gr_fb_width(void)
//{
//    return gr_draw->width - 2*overscan_offset_x;
//}
//
//int gr_fb_height(void)
//{
//    return gr_draw->height - 2*overscan_offset_y;
//}

int gr_fb_width() {
    if(!gr_draw)
        return 0;
    return rotation % 2 ? gr_draw->height - 2 * overscan_offset_y
                        : gr_draw->width - 2 * overscan_offset_x;
}

int gr_fb_height() {
    if(!gr_draw)
        return 0;
    return rotation % 2 ? gr_draw->width - 2 * overscan_offset_x
                        : gr_draw->height - 2 * overscan_offset_y;
}

void gr_fb_blank(bool blank)
{
    gr_backend->blank(gr_backend, blank);
}

void gr_rotate(GRRotation rot) {
    rotation = rot;
    printf("rotate degree: 0 - none, 1 - right, 2 - down, 3 - left.\n");
    printf("current rotate degree is : %d\n", rot);
}