// inventory art
BMAP* backpack_bmp = "backpack_panel.tga";
BMAP* items_bmp = "item_icons.tga";
BMAP* item_x48_bmp = "item_button_x48.tga";


// container variable arrays
var slot_owner[500];
var slot_number[500];
var item_slot_id[500];
var icon_bmp_x[500];
var icon_bmp_y[500];
var item_mdl_id[500];
var item_stack[500];
var drop_sound[500];


// pointers used for the 6 inventory pack slots
PANEL* pack_slot1;
PANEL* pack_slot2;
PANEL* pack_slot3;
PANEL* pack_slot4;
PANEL* pack_slot5;
PANEL* pack_slot6;


// helps determine the clicked slot number
var panel_slot_start = 0;

STRING* welcome_str = "Welcome";

TEXT* welcome_text =
{
  layer = 1;
  pos_x = 10;
  pos_y = 10;
  string (welcome_str,"this is","a","TEXT");
  flags = CENTER_X | TRANSLUCENT | SHOW;

}


function sort_panels(PANEL* panel)
{
	var list_no = 0;
	var sss = 0;
	
	PANEL* temp_panel;
	
	while(list_no < total_panels)
	{
		temp_panel = ptr_for_handle(panel_list[list_no]);
		if(temp_panel.layer > panel.layer && temp_panel != panel)
		{
			layer_sort(temp_panel,temp_panel.layer - 1);
		}
		list_no += 1;
	}
	
	layer_sort(panel,total_panels);
}


//moves a panel with mouse
function move_panel(PANEL* panel)
{
	
	//local variables
	VECTOR panel_vec;
	VECTOR pointer_vec;
	VECTOR panel_offset;
	
	vec_set(panel_vec.x,vector(panel.pos_x,panel.pos_y,0));
	
	//get initial mouse position
	pointer_vec.x = mouse_pos.x;
	pointer_vec.y = mouse_pos.y;
	
	sort_panels(panel);
	
	// while mouse held, loop
	while(mouse_left == 1)
	{
		panel_offset.x = mouse_pos.x - pointer_vec.x;
		panel_offset.y = mouse_pos.y - pointer_vec.y;
		
		panel.pos_x = panel_vec.x + panel_offset.x;
		panel.pos_y = panel_vec.y + panel_offset.y;
		
		// restrict panel positions to on-screen
		panel.pos_x = clamp(panel.pos_x,0,screen_size.x - panel.size_x);
		panel.pos_y = clamp(panel.pos_y,0,screen_size.y - panel.size_y);
		
		wait(1);
	}
}


// creates an icon bmp cutout from the slot number
function get_icon_cutout(var slot_no)
{
	
	BMAP* icon_bmp;
	STRING* icon_str = "item_icons.tga";
	
	str_cat(icon_str,"#");
	str_cat(icon_str,str_for_num(NULL,icon_bmp_x[slot_no]));
	str_cat(icon_str,"#");
	str_cat(icon_str,str_for_num(NULL,icon_bmp_y[slot_no]));
	str_cat(icon_str,"#48#48");
	
	icon_bmp = bmap_create(icon_str);
	return(icon_bmp);
}


// inventory panel click event
function inv_panel_click(PANEL* inv_panel)
{
	
	var format;
	var pixel;
	
	// lock and read panel background to determine if it was actually clicked
	format = bmap_lock(inv_panel.bmap,0);
	pixel = pixel_for_bmap(inv_panel.bmap,mouse_pos.x - inv_panel.pos_x,mouse_pos.y - inv_panel.pos_y);
	bmap_unlock(inv_panel.bmap);
	
	// if panel was clicked
	if(pixel != 0)
	{
		
		// if cursor is empty
		if(item_slot_id[0] == 0)
		{
			move_panel(inv_panel);
		}
		
		// bring this panel to front
		sort_panels(inv_panel);
	}
}


// fills the inv panel with an amount of inventory slots
function create_slots(PANEL* inv_panel, var rows, var cols, var start_x, var start_y, var start_slot)
{
	
	var rows_created = 0;
	var cols_created = 0;

	var x_pos;
	var y_pos;
	var slot_step;

	x_pos = start_x;
	y_pos = start_y;
	slot_step = start_slot;

	while(rows_created < rows)
	{
		
		while(cols_created < cols)
		{
			pan_setwindow(inv_panel,0,x_pos,y_pos,48,48,items_bmp,icon_bmp_x[slot_step],icon_bmp_y[slot_step]);
			pan_setbutton(inv_panel,0,0,x_pos,y_pos,item_x48_bmp,item_x48_bmp,item_x48_bmp,item_x48_bmp,NULL,NULL,NULL);
			
			x_pos += 48;
			slot_step ++;
			
			cols_created ++;
			
			wait(1);
		}
		
		y_pos += 48;
		x_pos = start_x;
		
		cols_created = 0;
		rows_created ++;
		
		
		wait(1);
	}
}


// creates the pack panel
function create_inv_panel(var start_slot, var x_pos, var y_pos)
{

	PANEL* inv_panel = pan_create("bmap = backpack_bmp; event = inv_panel_click;",1);
	
	inv_panel.pos_x = x_pos;
	inv_panel.pos_y = y_pos;
	
	create_slots(inv_panel,4,8,64,168,start_slot);
	
	register_panel(inv_panel);
	
	layer_sort(inv_panel,2);
	
	return(inv_panel);
}


// starts the inventory system
function inv_startup()
{
	
	BMAP* drag_icon;
	
	pack_slot1 = create_inv_panel(16,0,32);
	set(pack_slot1,SHOW);
	
	pack_slot2 = create_inv_panel(49,128,48);
	set(pack_slot2,SHOW);
	
	while(1)
	{
		
		if(key_1 == 1)
		{
			snd_play(select_snd,vol_effects,0);
			toggle(pack_slot1,SHOW);
			while(key_1 == 1){wait(1);}
		}
		
		// determine starting slot number for inventory mouse functions
		if(mouse_panel == pack_slot1){panel_slot_start = 16;}
		if(mouse_panel == pack_slot2){panel_slot_start = 49;}
		if(mouse_panel == pack_slot3){panel_slot_start = 81;}
		if(mouse_panel == pack_slot4){panel_slot_start = 113;}
		if(mouse_panel == pack_slot5){panel_slot_start = 145;}
		if(mouse_panel == pack_slot6){panel_slot_start = 177;}
		
		// mouse icon
		if(slot_number[0] != 0)
		{
			
			// create the icon cutout referencing the cursor slot
			drag_icon = get_icon_cutout(0);
			
			// draw the icon under the mouse cursor
			draw_quad(drag_icon,vector(mouse_pos.x - 24,mouse_pos.y - 24,0),NULL,vector(48,48,0),NULL,NULL,100,0);
		}
		
		wait(1);
	}
}