/* gui.c

   This file is part of the "First" CPU simulator project.

   Copyright (c) 2024 Efthymios Kritikos

   This program 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 Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include <ncurses.h>
#include <string.h>
#include "simdata.h"
#include "assembly.h"
#include <stdlib.h>
#include "cpu.h"

#define GENERAL_STACK_MAX_WIDTH 16
#define GENERAL_DISAS_WIDTH 41

int terminal_width;
int terminal_height;

WINDOW *tabs;
WINDOW *general_memdump;
WINDOW *general_stack;
WINDOW *general_disas;
WINDOW *general_registers;
WINDOW *general_terminal_output;

int monochrome;

int get_terminal_size(){
	int new_height,new_width;
	getmaxyx(stdscr,new_height,new_width);
	int changed=(new_width!=terminal_width)||(new_height!=terminal_height);
	terminal_width=new_width;
	terminal_height=new_height;
	return changed;
}

int gui_ncurses_refresh(){
	if(refresh()==ERR)
		return 1;
	if(wrefresh(tabs)==ERR)
		return 1;
	if(wrefresh(general_memdump)==ERR)
		return 1;
	if(wrefresh(general_stack)==ERR)
		return 1;
	if(wrefresh(general_disas)==ERR)
		return 1;
	if(wrefresh(general_registers)==ERR)
		return 1;
	if(wrefresh(general_terminal_output)==ERR)
		return 1;
	return 0;
}

char *tab_name[]={"Overview","Memory","Internal"};

unsigned int CURRENT_TAB=0;

enum GUI_CPU_STATE_t CPU_STATE=GUI_CPU_SINGLE_STEPPING;

void update_tabs(){
	wattron(tabs,A_BOLD);
	wattron(tabs,COLOR_PAIR(2));
	for(int i=0;i<terminal_width;i++)
		mvwprintw(tabs,0,i," ");

	int x=2;
	for(unsigned int i=0;i<sizeof(tab_name)/sizeof(tab_name[0]);i++){
		if(i==CURRENT_TAB)
			wattron(tabs,COLOR_PAIR(4));
		else
			wattron(tabs,COLOR_PAIR(5));
		mvwprintw(tabs,0,x," %1d",i);
		x+=2;
		if(i==CURRENT_TAB)
			wattron(tabs,COLOR_PAIR(3));
		else{
			wattron(tabs,COLOR_PAIR(2));
			wattroff(tabs,A_BOLD);
		}
		mvwprintw(tabs,0,x," %s ",tab_name[i]);
		wattron(tabs,A_BOLD);
		x+=strlen(tab_name[i])+2+3;
	}
	switch(CPU_STATE){
		case GUI_CPU_RUNNING:
			wattron(tabs,COLOR_PAIR(6));
			mvwprintw(tabs,0,terminal_width-13,"[ RUNNING ");
			break;
		case GUI_CPU_SINGLE_STEPPING:
			wattron(tabs,COLOR_PAIR(7));
			mvwprintw(tabs,0,terminal_width-21,"[ SINGLE-STEPPING ");
			break;
		case GUI_CPU_STOPPED:
			wattron(tabs,COLOR_PAIR(8));
			mvwprintw(tabs,0,terminal_width-13,"[ STOPPED ");
			break;
	}
	mvwprintw(tabs,0,terminal_width-3,"]");
}

int start_gui(){
	if(!initscr())
		return 1;
	monochrome=( has_colors() == FALSE );
	init_color(8, 700, 700, 700);
	init_color(COLOR_WHITE, 100, 1000, 1000);
	if(!monochrome){
		start_color();
		init_pair(1, COLOR_RED, COLOR_BLACK);

		//tab colors
		init_pair(2, COLOR_BLACK, 8);
		init_pair(3, 8, COLOR_BLACK);
		init_pair(4, COLOR_WHITE, COLOR_BLACK);
		init_pair(5, COLOR_WHITE, 8);
		init_pair(6, COLOR_BLACK,COLOR_GREEN);
		init_pair(7, COLOR_BLACK,COLOR_YELLOW);
		init_pair(8, COLOR_BLACK,COLOR_RED);

		//cpu instruction pipline location colors
		init_pair(9, COLOR_MAGENTA,COLOR_BLACK); //fetch
		init_pair(10, COLOR_YELLOW,COLOR_BLACK); //decode
		init_pair(11, COLOR_GREEN,COLOR_BLACK); //exec
		init_pair(12, COLOR_BLACK,COLOR_MAGENTA); //fetch
		init_pair(13, COLOR_BLACK,COLOR_YELLOW); //decode
		init_pair(14, COLOR_BLACK,COLOR_GREEN); //exec
	}
	noecho();
	curs_set(0);
	get_terminal_size();
	mvprintw((terminal_height-3)/2+3,terminal_width/2-15,"Initialising the simulator...");
	tabs = newwin(1,terminal_width,0,0);
	update_tabs();
	int len;

	int y1_divider,y2_divider;

	int border=4;

	if( (terminal_height-2*border-1)*0.2 < 8 )
		y1_divider=terminal_height-border-8;
	else if ( ( terminal_height - 2*border )*0.2 < 15 )
		y1_divider=terminal_height-border-11;
	else
		y1_divider=(terminal_height-border*2)*0.8;

	y2_divider=(3*(terminal_height-2*border-1)/4);

	int x=border;
	int middle;

	general_memdump=newwin(y1_divider,terminal_width/2,x,border);
	x+=terminal_width/2;
	x++;

	x+=3;
	middle=x;
	len=(terminal_width/6)>GENERAL_DISAS_WIDTH?GENERAL_DISAS_WIDTH:(terminal_width/6);
	general_disas=newwin(y2_divider,len,4,x);
	x+=len;

	x+=3;
	len=(terminal_width/6)>GENERAL_STACK_MAX_WIDTH?GENERAL_STACK_MAX_WIDTH:(terminal_width/6);
	general_stack=newwin(y2_divider,len,4,x);
	x+=len;

	general_registers=newwin(terminal_height-y1_divider-border-1,terminal_width/2,y1_divider+border+1,border);
	x+=terminal_width/2;
	x++;

	general_terminal_output=newwin(terminal_height-y2_divider-border-1,terminal_width/2-3*border,y2_divider+border+1,middle);
	scrollok(general_terminal_output,TRUE);
	x+=terminal_width/2;
	x++;

	if(gui_ncurses_refresh())
		return 1;
	return 0;
}


int gui_error(char *str){
	WINDOW *error_win = newwin(3,40,terminal_height/2-1,terminal_width/2-20);
	box(error_win, 0 , 0);
	if(!monochrome)
		wattron(error_win,COLOR_PAIR(1));
	mvwprintw(error_win,1,1,"%s",str);
	if(wrefresh(error_win)==ERR)
		return 1;
	getch();
	delwin(error_win);
	return 0;

	if(!monochrome)
		wattroff(error_win,COLOR_PAIR(1));
}

//// WARNING!! THIS ASSUMES THAT ADDRESS IS CORRECTLY ALIGNED WITH THE INSTRUCTION START/END!!
int select_instruction_color(struct simdata_t *simdata, WINDOW* window,uint32_t ADDRESS, int applyremove){
	if(simdata->cpu_gui_hints){
		struct instr_list_t* pointer;
		pointer=simdata->cpu_gui_hints->fetching_list;
		while(pointer!=NULL){
			if(pointer->address==ADDRESS){
				if(applyremove)
					wattron(window,COLOR_PAIR(9));
				else
					wattroff(window,COLOR_PAIR(9));
				return 0;
			}
			pointer=pointer->next;
		}
		pointer=simdata->cpu_gui_hints->decoding_list;
		while(pointer!=NULL){
			if(pointer->address==ADDRESS){
				if(applyremove)
					wattron(window,COLOR_PAIR(10));
				else
					wattroff(window,COLOR_PAIR(10));
				return 0;
			}
			pointer=pointer->next;
		}
		pointer=simdata->cpu_gui_hints->executing_list;
		while(pointer!=NULL){
			if(pointer->address==ADDRESS){
				if(applyremove)
					wattron(window,COLOR_PAIR(11));
				else
					wattroff(window,COLOR_PAIR(11));
				return 0;
			}
			pointer=pointer->next;
		}
	}
	return 1;
}

int update_general_disas(struct simdata_t *simdata){
	werase(general_disas);
	int width,height;
	getmaxyx(general_disas,height,width);
	box(general_disas, 0 , 0);
	mvwprintw(general_disas,0,width/2-7,"[ DISASSEMBLY ]");
	if(simdata->registers==NULL||simdata->RAM==NULL){
		mvwprintw(general_disas,1,1,"Data not initialised");
		return 0;
	}
	int offset_arrow;

	int have_legend=(width>29);

	int usable_height=height-2-have_legend;

	if(width<41)
		offset_arrow=2;
	else
		offset_arrow=3;
	if(width<18){
		mvwprintw(general_disas,1,1,"too small window");
	}else{
		uint32_t ADDRESS=(simdata->registers->PC-(usable_height/2-2)*4)&0x00FFFFFF;
		for (int i=2;i<usable_height;i++){
			int overall_offset=offset_arrow-2;

			mvwaddch(general_disas,i,11+overall_offset,ACS_VLINE);

			if(ADDRESS==simdata->registers->PC)
				wattron(general_disas,A_BOLD);
			mvwprintw(general_disas,i,4+overall_offset,"%06X",ADDRESS);
			char* disas=disassemble(*(uint32_t*)(simdata->RAM+ADDRESS));
			int space_left=width-14-2+(overall_offset?0:1);
			if(space_left<25)
				disas[space_left+1]=0;

			select_instruction_color(simdata,general_disas,ADDRESS,1);
			mvwprintw(general_disas,i,13+overall_offset,"%s",disas);
			select_instruction_color(simdata,general_disas,ADDRESS,0);

			if(ADDRESS==simdata->registers->PC)
				wattroff(general_disas,A_BOLD);

			ADDRESS=(ADDRESS+4)&0xFFFFFF;
			free(disas);
		}
		mvwaddch(general_disas,usable_height/2,offset_arrow,ACS_RARROW);
		mvwaddch(general_disas,usable_height/2,offset_arrow-1,ACS_ULCORNER);
		mvwaddch(general_disas,usable_height/2+1,offset_arrow-1,ACS_VLINE);
		mvwaddch(general_disas,usable_height/2+2,offset_arrow-1,ACS_VLINE);
		mvwaddch(general_disas,usable_height/2+3,offset_arrow-1,ACS_VLINE);
		mvwaddch(general_disas,usable_height/2+4,offset_arrow-1,ACS_VLINE);
		mvwaddch(general_disas,usable_height/2+5,offset_arrow-1,ACS_VLINE);
		mvwaddch(general_disas,usable_height/2+6,offset_arrow-1,'P');
		if(offset_arrow==2)
			mvwaddch(general_disas,usable_height/2+7,offset_arrow-1,'C');
		else
			mvwaddch(general_disas,usable_height/2+6,offset_arrow,'C');
		if(have_legend){
			wattron(general_disas,COLOR_PAIR(12));
			mvwprintw(general_disas,height-2,2,"  ");
			wattroff(general_disas,COLOR_PAIR(12));
			mvwprintw(general_disas,height-2,4,"=Fetch");

			wattron(general_disas,COLOR_PAIR(13));
			mvwprintw(general_disas,height-2,11,"  ");
			wattroff(general_disas,COLOR_PAIR(13));
			mvwprintw(general_disas,height-2,13,"=Decode");

			wattron(general_disas,COLOR_PAIR(14));
			mvwprintw(general_disas,height-2,21,"  ");
			wattroff(general_disas,COLOR_PAIR(14));
			mvwprintw(general_disas,height-2,23,"=Exec");
		}

	}
	return 0;
}

int update_general_stack(struct simdata_t *simdata){
	int width,height;
	getmaxyx(general_stack,height,width);
	box(general_stack, 0 , 0);
	mvwprintw(general_stack,0,width/2-4,"[ STACK ]");
	if(simdata->registers==NULL||simdata->RAM==NULL){
		mvwprintw(general_stack,1,1,"Data not initialised");
		return 0;
	}
	if(width<13){
		mvwprintw(general_stack,1,1,"too small window");
	}else{
		// Calculate config based on window size
		int offset_data,offset_arrow;
		if(width<14){
			offset_data=3;
			offset_arrow=2;
		}else{
			offset_data=5;
			offset_arrow=3;
		}

		// draw data
		uint32_t ADDRESS=(simdata->registers->SP-(height/2-2)*4)&0x00FFFFFF;

		for(int i=0;i<height-4;i++){
			if(ADDRESS==simdata->registers->SP)
				wattron(general_stack,A_BOLD);
			mvwprintw(general_stack,i+2,offset_data,"%08X",*(uint32_t*)(simdata->RAM+ADDRESS));
			if(ADDRESS==simdata->registers->SP)
				wattroff(general_stack,A_BOLD);
			ADDRESS=(ADDRESS+4)&0xFFFFFF;
		}

		// draw graphics
		mvwaddch(general_stack,height/4-2,offset_arrow-1,ACS_UARROW);
		mvwaddch(general_stack,height/4-1,offset_arrow-1,ACS_VLINE);
		mvwaddch(general_stack,height/4  ,offset_arrow-1,ACS_VLINE);
		mvwaddch(general_stack,height/4+1,offset_arrow-1,ACS_VLINE);
		if(offset_arrow!=2)
			mvwprintw(general_stack,height/4+2,1,"(+)");
		else
			mvwprintw(general_stack,height/4+2,offset_arrow-1,"+");


		mvwaddch(general_stack,height/2,offset_arrow,ACS_RARROW);
		mvwaddch(general_stack,height/2,offset_arrow-1,ACS_ULCORNER);

		mvwaddch(general_stack,height/2+1,offset_arrow-1,ACS_VLINE);
		mvwaddch(general_stack,height/2+2,offset_arrow-1,ACS_VLINE);
		mvwaddch(general_stack,height/2+3,offset_arrow-1,ACS_VLINE);
		mvwaddch(general_stack,height/2+4,offset_arrow-1,'S');
		if(offset_arrow==2)
			mvwaddch(general_stack,height/2+5,offset_arrow-1,'P');
		else
			mvwaddch(general_stack,height/2+4,offset_arrow,'P');
	}
	return 0;
}

int update_general_memdump(struct simdata_t *simdata){
	int width,height;
	getmaxyx(general_memdump,height,width);
	box(general_memdump, 0 , 0);
	mvwprintw(general_memdump,0,terminal_width/4-6,"[ MEMDUMP ]");
	if(simdata->registers==NULL||simdata->RAM==NULL){
		mvwprintw(general_memdump,1,1,"Data not initialised");
		return 0;
	}
	if(width<16){
		mvwprintw(general_memdump,1,1,"too small window");
	}else{
		int n=(width-12)/4; // bytes in each line
		int usable_height=height-3-(width-12)%2;

		uint32_t ADDRESS=(simdata->registers->PC-n*usable_height/2)&0x00FFFFFF;

		uint32_t color_addr;
		int have_color;
		for(int h=0;h<usable_height;h++){
			wmove(general_memdump,h+2,2+(width-12)%2);
			wattroff(general_memdump,A_BOLD);
			wprintw(general_memdump,"%06x  ",ADDRESS);
			uint32_t temp_address=ADDRESS;
			for (int i=0;i<n;i++){
				if(ADDRESS>=simdata->registers->PC&&ADDRESS<=simdata->registers->PC+3)
					wattron(general_memdump,A_BOLD);
				else
					wattroff(general_memdump,A_BOLD);
				if(select_instruction_color(simdata,general_memdump,ADDRESS,1)==0){
					have_color=5;
					color_addr=ADDRESS;
				}else if(have_color)
					select_instruction_color(simdata,general_memdump,color_addr,1);
				if(have_color){
					have_color--;
					if(!have_color)
						select_instruction_color(simdata,general_memdump,color_addr,0);
				}
				wprintw(general_memdump,"%02x ",simdata->RAM[ADDRESS]);
				ADDRESS=(ADDRESS+1)&0xFFFFFF;
			}
			if(have_color)
				select_instruction_color(simdata,general_memdump,color_addr,0);
			ADDRESS=temp_address;
			for (int i=0;i<n;i++){
				if(ADDRESS>=simdata->registers->PC&&ADDRESS<=simdata->registers->PC+3)
					wattron(general_memdump,A_BOLD);
				else
					wattroff(general_memdump,A_BOLD);
				wprintw(general_memdump,"%c",(simdata->RAM[ADDRESS]>=0x20&&simdata->RAM[ADDRESS]<0x7F)?simdata->RAM[ADDRESS]:'.');
				ADDRESS=(ADDRESS+1)&0xFFFFFF;
			}
		}
	}
	return 0;
}

int update_general_registers(struct simdata_t *simdata){
	int width,height;
	werase(general_registers);
	getmaxyx(general_registers,height,width);
	box(general_registers, 0 , 0);
	mvwprintw(general_registers,0,terminal_width/4-7,"[ REGISTERS ]");
	if(simdata->registers==NULL){
		mvwprintw(general_registers,1,1,"Data not initialised");
		return 0;
	}
	if(simdata->registers==NULL)
		mvwprintw(general_registers,1,1,"Registers data structure not initialised");
	else{
		int per_line=width/35;
		if(per_line==0)
			mvwprintw(general_registers,1,1,"too small window");
		else{
			int center_x_offset=((width-2)-35*per_line)/2;
			int lines_used=(8/(int)per_line<8/(float)per_line)?8/per_line+1:8/per_line;

			int lines_for_special_registers;
			lines_for_special_registers=( width < 22+27+8 )?2:1;

			int center_y_offset=((height-2)-(lines_used+lines_for_special_registers+1))/2;

			if((lines_used+lines_for_special_registers+1)>(height-2)||width<37)
				mvwprintw(general_registers,1,1,"too small window");
			else{
				int n=0,y=0;
				while(y!=lines_used){
					for(int i=0;i<per_line;i++){
						if(n<8){
							float float_equiv=*(float*)(simdata->registers->GPR+n);
							if(float_equiv<9999999999&&float_equiv>-9999999999)
								mvwprintw(general_registers,1+y+center_y_offset,1+i*35+center_x_offset,"R%d: %08X (%08f) ",n,simdata->registers->GPR[n],float_equiv);
							else
								mvwprintw(general_registers,1+y+center_y_offset,1+i*35+center_x_offset,"R%d: %08X (%cinf) ",n,simdata->registers->GPR[n],(float_equiv>0)?'+':'-');
							n++;
						}
					}
					y++;
				}

				for(int i=0;i<35*per_line;i++)
					mvwaddch(general_registers,1+center_y_offset+lines_used,center_x_offset+i,ACS_HLINE);

				int spec_reg_1_offset, spec_reg_2_offset;

				if(lines_for_special_registers==2){
					spec_reg_1_offset=((width-2)/2)-(23/2);
					spec_reg_2_offset=((width-2)/2)-(27/2);
				}else{
					spec_reg_1_offset=((width-2)/2)-(22+27+8)/2;
					spec_reg_2_offset=spec_reg_1_offset+22+8;
				}

				wattron(general_registers,A_BOLD);
				mvwprintw(general_registers,1+center_y_offset+lines_used+1,spec_reg_1_offset,"  PC");
				wattroff(general_registers,A_BOLD);
				wprintw(general_registers,": %06X  ",simdata->registers->PC);

				wattron(general_registers,A_BOLD);
				wprintw(general_registers,"SP");
				wattroff(general_registers,A_BOLD);
				wprintw(general_registers,": %06X  ",simdata->registers->SP);

				wattron(general_registers,A_BOLD);
				mvwprintw(general_registers,center_y_offset+lines_used+1+lines_for_special_registers,spec_reg_2_offset,"  ZERO");
				wattroff(general_registers,A_BOLD);
				wprintw(general_registers,": %c  ",(simdata->registers->FLAGS&1)?'1':'0');

				wattron(general_registers,A_BOLD);
				wprintw(general_registers,"CARRY");
				wattroff(general_registers,A_BOLD);
				wprintw(general_registers,": %c  ",(simdata->registers->FLAGS&2)?'1':'0');

				wattron(general_registers,A_BOLD);
				wprintw(general_registers,"SIGN");
				wattroff(general_registers,A_BOLD);
				wprintw(general_registers,": %c  ",(simdata->registers->FLAGS&4)?'1':'0');
			}
		}
	}
	return 0;
}

int term_curs_x,term_curs_y;

int update_general_terminal_output(struct simdata_t *simdata){
	int width,height;
	werase(general_terminal_output);
	getmaxyx(general_terminal_output,height,width);
	box(general_terminal_output, 0 , 0);
	mvwprintw(general_terminal_output,0,width/2-7,"[ TERM OUTPUT ]");

	term_curs_x=0;
	term_curs_y=0;

	for(uint64_t i=0;i < simdata->terminal_output_size;i++){
		char c=simdata->terminal_output[i];
		if(c>=' '&&c<='~'){
			mvwprintw(general_terminal_output,term_curs_y+1,term_curs_x+1,"%c",c);
			term_curs_x++;
			if(term_curs_x>=width-2){
				term_curs_x=0;
				term_curs_y++;
			}
			if(term_curs_y>=height-2){
				wscrl(general_terminal_output,1);
				term_curs_y--;
				for(int i=0;i<width;i++){
					mvwprintw(general_terminal_output,term_curs_y+1,i," ");
				}
				box(general_terminal_output, 0 , 0);
				mvwprintw(general_terminal_output,0,width/2-7,"[ TERM OUTPUT ]");
			}
		}else{
			switch(c){
				case 0x0a:
					term_curs_x=0;
					term_curs_y++;
					if(term_curs_y>=height-2){
						wscrl(general_terminal_output,1);
						term_curs_y--;
						for(int i=0;i<width;i++){
							mvwprintw(general_terminal_output,term_curs_y+1,i," ");
						}
						box(general_terminal_output, 0 , 0);
						mvwprintw(general_terminal_output,0,width/2-7,"[ TERM OUTPUT ]");
					}
					break;
				default:
					werase(general_terminal_output);
					box(general_terminal_output, 0 , 0);
					mvwprintw(general_terminal_output,0,width/2-7,"[ TERM OUTPUT ]");
					mvwprintw(general_terminal_output,1,1,"Invalid output");
					return 0;
			}
		}
	}
	mvwchgat(general_terminal_output,term_curs_y+1,term_curs_x+1,   1, A_REVERSE, 0, NULL);

	return 0;
}

int clear_back_window=1;

int update_gui(struct simdata_t *simdata){
	if(simdata->cpu_state==CPU_HALTED)
		CPU_STATE=GUI_CPU_STOPPED;
	if(clear_back_window){
		clear();
		clear_back_window=0;
	}
	update_tabs();
	if(update_general_memdump(simdata))
		return 1;
	if(update_general_stack(simdata))
		return 1;
	if(update_general_disas(simdata))
		return 1;
	if(update_general_registers(simdata))
		return 1;
	if(update_general_terminal_output(simdata))
		return 1;
	if(gui_ncurses_refresh())
		return 1;
	return 0;
}

int gui_continue_request(struct simdata_t *simdata){
	int inch;
	int release=0;
	while(release==0){
		if(((inch=getch())==ERR)){
			if(CPU_STATE==GUI_CPU_SINGLE_STEPPING)
				return 1;
			else
				release=1;
		}
		switch(inch){
			case 'r':
				if(simdata->cpu_state!=CPU_HALTED){
					if(CPU_STATE==GUI_CPU_RUNNING){
						CPU_STATE=GUI_CPU_SINGLE_STEPPING;
						nodelay(stdscr, FALSE);
					}else{
						CPU_STATE=GUI_CPU_RUNNING;
						nodelay(stdscr, TRUE);
					}
				}
				break;
			case 'q':
				return 2;
			case '\n':
				release=1;
				break;
			default:
		}
	}
	return 0;
}

int end_gui(){
	if(endwin()==ERR)
		return 1;
	return 0;
}