/* copyright (c) 2007 magnus auvinen, see licence.txt for more info */
#include <engine/e_system.h>
#include <engine/e_interface.h>
#include <engine/e_config.h>
#include "ec_ui.h"

/********************************************************
 UI                                                      
*********************************************************/

struct pretty_font
{
    float m_CharStartTable[256];
	float m_CharEndTable[256];
	int font_texture;
};

extern struct pretty_font *current_font;

static const void *hot_item = 0;
static const void *active_item = 0;
static const void *last_active_item = 0;
static const void *becomming_hot_item = 0;
static float mouse_x, mouse_y; /* in gui space */
static float mouse_wx, mouse_wy; /* in world space */
static unsigned mouse_buttons = 0;

float ui_mouse_x() { return mouse_x; }
float ui_mouse_y() { return mouse_y; }
float ui_mouse_world_x() { return mouse_wx; }
float ui_mouse_world_y() { return mouse_wy; }
int ui_mouse_button(int index) { return (mouse_buttons>>index)&1; }

void ui_set_hot_item(const void *id) { becomming_hot_item = id; }
void ui_set_active_item(const void *id) { active_item = id; if (id) last_active_item = id; }
void ui_clear_last_active_item() { last_active_item = 0; }
const void *ui_hot_item() { return hot_item; }
const void *ui_active_item() { return active_item; }
const void *ui_last_active_item() { return last_active_item; }

int ui_update(float mx, float my, float mwx, float mwy, int buttons)
{
    mouse_x = mx;
    mouse_y = my;
    mouse_wx = mwx;
    mouse_wy = mwy;
    mouse_buttons = buttons;
    hot_item = becomming_hot_item;
    if(active_item)
    	hot_item = active_item;
    becomming_hot_item = 0;
    return 0;
}

int ui_mouse_inside(float x, float y, float w, float h)
{
    if(mouse_x >= x && mouse_x <= x+w && mouse_y >= y && mouse_y <= y+h)
        return 1;
    return 0;
}

void ui_do_image(int texture, float x, float y, float w, float h)
{
    gfx_blend_normal();
    gfx_texture_set(texture);
    gfx_quads_begin();
    gfx_setcolor(1,1,1,1);
    gfx_quads_setsubset(
        0.0f, /* startx */
        0.0f, /* starty */
        1.0f, /* endx */
        1.0f); /* endy */                              
    gfx_quads_drawTL(x,y,w,h);
    gfx_quads_end();
}

void ui_do_label(float x, float y, const char *text, float size)
{
    gfx_blend_normal();
    gfx_texture_set(current_font->font_texture);
    gfx_pretty_text(x, y, size, text, -1);
}

int ui_do_button(const void *id, const char *text, int checked, float x, float y, float w, float h, draw_button_callback draw_func, void *extra)
{
    /* logic */
    int r = 0;
    int inside = ui_mouse_inside(x,y,w,h);

	if(ui_active_item() == id)
	{
		if(!ui_mouse_button(0))
		{
			if(inside)
				r = 1;
			ui_set_active_item(0);
		}
	}
	else if(ui_hot_item() == id)
	{
		if(ui_mouse_button(0))
			ui_set_active_item(id);
	}
	
	if(inside)
		ui_set_hot_item(id);

    draw_func(id, text, checked, x, y, w, h, extra);
    return r;
}

static float scale = 1.0f;
#define MEMORY_SIZE 10*1024
static struct rect memory[MEMORY_SIZE];
static int memory_used = 0;
static struct rect screen = { 0.0f, 0.0f, 848.0f, 480.0f };

void ui_foreach_rect(rect_fun fun)
{
    int hrm;
    for (hrm = 0; hrm < memory_used; hrm++)
        fun(&memory[hrm]);
}

static void add_rect(struct rect *r)
{
    if (memory_used < MEMORY_SIZE)
        memory[memory_used++] = *r;
    else
        dbg_msg("ui", "rect memory full.");
}

struct rect *ui_screen()
{
    if (config.debug)
    {
        memory_used = 0;
    }

    return &screen;
}

void ui_scale(float s)
{
    scale = s;
}

void ui_hsplit_t(const struct rect *original, int pixels, struct rect *top, struct rect *bottom)
{
    struct rect r = *original;
    pixels *= scale;

    if (top)
    {
        top->x = r.x;
        top->y = r.y;
        top->w = r.w;
        top->h = pixels;
    }

    if (bottom)
    {
        bottom->x = r.x;
        bottom->y = r.y + pixels;
        bottom->w = r.w;
        bottom->h = r.h - pixels;
    }

    if (config.debug)
    {
        if (top)
            add_rect(top);
        if (bottom)
            add_rect(bottom);
    }
}

void ui_hsplit_b(const struct rect *original, int pixels, struct rect *top, struct rect *bottom)
{
    struct rect r = *original;
    pixels *= scale;

    if (top)
    {
        top->x = r.x;
        top->y = r.y;
        top->w = r.w;
        top->h = r.h - pixels;
    }

    if (bottom)
    {
        bottom->x = r.x;
        bottom->y = r.y + r.h - pixels;
        bottom->w = r.w;
        bottom->h = pixels;
    }

    if (config.debug)
    {
        if (top)
            add_rect(top);
        if (bottom)
            add_rect(bottom);
    }
}

void ui_vsplit_l(const struct rect *original, int pixels, struct rect *left, struct rect *right)
{
    struct rect r = *original;
    pixels *= scale;

    if (left)
    {
        left->x = r.x;
        left->y = r.y;
        left->w = pixels;
        left->h = r.h;
    }

    if (right)
    {
        right->x = r.x + pixels;
        right->y = r.y;
        right->w = r.w - pixels;
        right->h = r.h;
    }

    if (config.debug)
    {
        if (left)
            add_rect(left);
        if (right)
            add_rect(right);
    }
}

void ui_vsplit_r(const struct rect *original, int pixels, struct rect *left, struct rect *right)
{
    struct rect r = *original;
    pixels *= scale;

    if (left)
    {
        left->x = r.x;
        left->y = r.y;
        left->w = r.w - pixels;
        left->h = r.h;
    }

    if (right)
    {
        right->x = r.x + r.w - pixels;
        right->y = r.y;
        right->w = pixels;
        right->h = r.h;
    }

    if (config.debug)
    {
        if (left)
            add_rect(left);
        if (right)
            add_rect(right);
    }
}

void ui_margin(const struct rect *original, int pixels, struct rect *other_rect)
{
    struct rect r = *original;
    pixels *= scale;

    other_rect->x = r.x + pixels;
    other_rect->y = r.y + pixels;
    other_rect->w = r.w - 2*pixels;
    other_rect->h = r.h - 2*pixels;
}

typedef struct
{
    short x, y;
    short width, height;
    short x_offset, y_offset;
    short x_advance;
} FONT_CHARACTER;

typedef struct
{
    short size;
    short width, height;

    short line_height;
    short base;

    FONT_CHARACTER characters[256];

    short kerning[256*256];
} FONT_DATA;

int font_load(FONT *font, const char *filename)
{
    FONT_DATA font_data;
	IOHANDLE file;

	dbg_msg("font/load", "loading %s", filename);
	file = io_open(filename, IOFLAG_READ);
	
	if(file)
	{
        int i;

        io_read(file, &font_data, sizeof(FONT_DATA));
        io_close(file);

#if defined(CONF_ARCH_ENDIAN_BIG)
        swap_endian(&font_data, 2, sizeof(FONT_DATA)/2);
#endif

        dbg_msg("font/load", "width: %d, height: %d, sizeof(FONT_DATA): %d", font_data.width, font_data.height, sizeof(FONT_DATA));

        {
            float scale_factor_x = ((float)font_data.size)/font_data.width;
            float scale_factor_y = ((float)font_data.size)/font_data.height;
            float scale_factor_tex_x = 1.0f/font_data.width;
            float scale_factor_tex_y = 1.0f/font_data.height;

            for (i = 0; i < 256; i++)
            {
                float tex_x0 = font_data.characters[i].x*scale_factor_tex_x;
                float tex_y0 = font_data.characters[i].y*scale_factor_tex_y;
                float tex_x1 = (font_data.characters[i].x+font_data.characters[i].width)*scale_factor_tex_x;
                float tex_y1 = (font_data.characters[i].y+font_data.characters[i].height)*scale_factor_tex_y;

                float width = font_data.characters[i].width*scale_factor_x;
                float height = font_data.characters[i].height*scale_factor_y;
                float x_offset = font_data.characters[i].x_offset*scale_factor_x;
                float y_offset = font_data.characters[i].y_offset*scale_factor_y;
                float x_advance = font_data.characters[i].x_advance*scale_factor_x;

                font->characters[i].tex_x0 = tex_x0;
                font->characters[i].tex_y0 = tex_y0;
                font->characters[i].tex_x1 = tex_x1;
                font->characters[i].tex_y1 = tex_y1;
                font->characters[i].width = width;
                font->characters[i].height = height;
                font->characters[i].x_offset = x_offset;
                font->characters[i].y_offset = y_offset;
                font->characters[i].x_advance = x_advance;

            }

            for (i = 0; i < 256*256; i++)
            {
                font->kerning[i] = font_data.kerning[i]*scale_factor_x;
            }
        }

        return 0;
    }
    else
        return -1;
}

int font_save(FONT *font, const char *filename)
{
    return 0;
}

float font_string_width(FONT *font, const char *string, float size)
{
    float width = 0.0f;

    const unsigned char *c = (unsigned char *)string;

    while (*c)
    {
        float tex_x0, tex_y0, tex_x1, tex_y1;
        float char_width, char_height;
        float x_offset, y_offset, x_advance;

        font_character_info(font, *c, &tex_x0, &tex_y0, &tex_x1, &tex_y1, &char_width, &char_height, &x_offset, &y_offset, &x_advance);


        width += x_advance;

        c++;
    }


    return width*size;
}

void font_character_info(FONT *font, unsigned char c, float *tex_x0, float *tex_y0, float *tex_x1, float *tex_y1, float *width, float *height, float *x_offset, float *y_offset, float *x_advance)
{
    CHARACTER *character = &font->characters[c];

    *tex_x0 = character->tex_x0;
    *tex_y0 = character->tex_y0;
    *tex_x1 = character->tex_x1;
    *tex_y1 = character->tex_y1;
    *width = character->width;
    *height = character->height;
    *x_offset = character->x_offset;
    *y_offset = character->y_offset;
    *x_advance = character->x_advance;
}

void font_render(FONT *font, const char *string, float x, float y, float size)
{
    const unsigned char *c = (unsigned char *)string;

    gfx_texture_set(font->texture);

	gfx_quads_begin();
	gfx_setcolor(1.0f, 1.0f, 1.0f, 1.0f);
    
    while (*c)
    {
        float tex_x0, tex_y0, tex_x1, tex_y1;
        float width, height;
        float x_offset, y_offset, x_advance;

        font_character_info(font, *c, &tex_x0, &tex_y0, &tex_x1, &tex_y1, &width, &height, &x_offset, &y_offset, &x_advance);

		gfx_quads_setsubset(tex_x0, tex_y0, tex_x1, tex_y1);

		gfx_quads_drawTL(x+x_offset*size, y+y_offset*size, width*size, height*size);

        x += x_advance*size;

        c++;
    }

	gfx_quads_end();
}