#include <ncurses.h>
#include <form.h>
#include <signal.h>
#include "contract.h"
#include "loans.h"

static int WIDTH, HEIGHT;
static int padscroll, duration;
static WINDOW *pad;
_Noreturn static void finish(int sig);
void display_custom_form(FORM *);
void print_contract(WINDOW *w, int x, int y, contract *c);
int run_sim(FORM *, char **contract_subtypes);
int min(int a, int b);

int main() {
	int ch, i;

	/* setup ncurses */
	signal(SIGINT, finish); /* arrange interrupts to terminate */
	initscr(); /* initialize the curses library */
	cbreak(); /* take input chars one at a time don't wait for CR */
	noecho(); /* echo input */
	nonl(); /* do not LF->CR-LF on output */
	intrflush(stdscr, FALSE); /* do not flush on interrupts */
	keypad(stdscr, TRUE); /* enable keyboard mapping */
	getmaxyx(stdscr, HEIGHT, WIDTH);

	/* create the form */
	FIELD *fields[8];
	FORM *form;
	char *contract_types[] = { "loan", "savings", NULL };
	char *contract_subtypes[] = { "bullet", "sla", "mortgage", NULL };

	/* initialize fields */
	fields[0] = new_field(1, 11, 4, 22, 0, 0); /* contract type */
	set_field_type(fields[0], TYPE_ENUM, contract_types, FALSE, TRUE);
	fields[1] = new_field(1, 11, 5, 22, 0, 0); /* contract subtype */
	set_field_type(fields[1], TYPE_ENUM, contract_subtypes, FALSE, TRUE);
	fields[2] = new_field(1, 11, 6, 22, 0, 0); /* contract duration */
	set_field_type(fields[2], TYPE_INTEGER, 1, 0, INT_MAX);
	fields[3] = new_field(1, 11, 7, 22, 0, 0); /* yearly payments */
	set_field_type(fields[3], TYPE_INTEGER, 1, 0, INT_MAX);
	fields[4] = new_field(1, 11, 8, 22, 0, 0); /* delay duration */
	set_field_type(fields[4], TYPE_INTEGER, 1, 0, INT_MAX);
	fields[5] = new_field(1, 11, 9, 22, 0, 0); /* starting amount */
	set_field_type(fields[5], TYPE_NUMERIC, 2, 0.01, 0.0);
	fields[6] = new_field(1, 11, 10, 22, 0, 0); /* rate */
	set_field_type(fields[6], TYPE_NUMERIC, 3, 0.0, 1.0);
	fields[7] = NULL;

	/* configure fields */
	for (i = 0; fields[i]; i++) {
		set_field_back(fields[i], A_UNDERLINE);		/* Print a line for the option	*/
		field_opts_off(fields[i], O_AUTOSKIP);		/* Don't go to next field when this */
													/* Field is filled up		*/
	}

	/* create form */
	form = new_form(fields);
	display_custom_form(form);
	refresh();

	int formactive = TRUE;
	/* mainloop */
	while ((ch = getch()) != KEY_EXIT) {
		if (formactive) {
			switch (ch) {
			case KEY_DOWN:
				/* Go to next field */
				form_driver(form, REQ_NEXT_FIELD);
				/* Go to the end of the present buffer */
				/* Leaves nicely at the last character */
				form_driver(form, REQ_END_LINE);
				break;
			case KEY_UP:
				form_driver(form, REQ_PREV_FIELD);
				form_driver(form, REQ_END_LINE);
				break;
			case KEY_LEFT:
				form_driver(form, REQ_PREV_CHOICE);
				break;
			case KEY_RIGHT:
				form_driver(form, REQ_NEXT_CHOICE);
				break;
			case KEY_BACKSPACE:
				form_driver(form, REQ_DEL_PREV);
				break;
			case '\r':
				if ((E_OK == form_driver(form, REQ_VALIDATION))
					&& run_sim(form, contract_subtypes)) {
					unpost_form(form);
					formactive = FALSE;
					curs_set(0);
					box(stdscr, 0, 0);
					padscroll = 0;
					mvwprintw(stdscr, 1, 2, "Reinbursement Table");
					mvwprintw(stdscr, 3, 3,
							  "%4s/%-4s | %12s | %10s | %10s | %10s\n",
							  "cur", "tot",
							  "principal",
							  "interest",
							  "part",
							  "annuity");
					refresh();
					prefresh(pad, padscroll, 0, 4, 1, HEIGHT-2, WIDTH-1);
				}
				break;
			default:
				/* If this is a normal character, it gets */
				/* Printed				  */
				form_driver(form, ch);
			}
		} else {
			switch (ch) {
			case KEY_DOWN:
				padscroll += (padscroll < duration) ? 1 : 0;
				pnoutrefresh(pad, padscroll, 0, 4, 1, HEIGHT-2, WIDTH-1);
				doupdate();
				break;
			case KEY_UP:
				padscroll -= (padscroll > 0) ? 1 : 0;
				pnoutrefresh(pad, padscroll, 0, 4, 1, HEIGHT-2, WIDTH-1);
				doupdate();
				break;
			case KEY_NPAGE:
				padscroll += min(HEIGHT - 6, duration - padscroll);
				pnoutrefresh(pad, padscroll, 0, 4, 1, HEIGHT-2, WIDTH-1);
				doupdate();
				break;
			case KEY_PPAGE:
				padscroll -= min(HEIGHT - 6, padscroll);
				pnoutrefresh(pad, padscroll, 0, 4, 1, HEIGHT-2, WIDTH-1);
				doupdate();
				break;
			case 'q':
				display_custom_form(form);
				formactive = TRUE;
				curs_set(1);
				break;
			}
		}
	}

	delwin(pad);
	if (formactive) unpost_form(form);
	free_form(form);
	for (i = 0; fields[i]; i++)
		free_field(fields[i]);

	finish(0);
}

_Noreturn static void finish (int sig) {
	endwin();

	exit(sig);
}

void display_custom_form(FORM *form) {
	post_form(form);
	mvprintw(2, 5, "Initialization Parameters");
	mvprintw(4, 2, "Contract type:");
	mvprintw(5, 2, "Contract subtype:");
	mvprintw(6, 2, "Contract Duration:");
	mvprintw(7, 2, "Yearly payments:");
	mvprintw(8, 2, "Delay Duration:");
	mvprintw(9, 2, "Starting Amount:");
	mvprintw(10, 2, "Rate:");
	form_driver(form, REQ_FIRST_FIELD);	
}

void print_contract(WINDOW* w, int x, int y, contract *c) {
	mvwprintw(w, x, y,
			 "%4d/%-4d | %12.2f | %10.2f | %10.2f | %10.2f\n",
			 c->k, c->n,
			 (double)c->P, (double)c->I,
			 (double)c->D, (double)c->A);
}

int run_sim(FORM *form, char **contract_subtypes) {
	/* loan_type type; */
	int n, d, yp;
	double r, p;
	loan_type lt;

	FIELD **fields = form_fields(form);
	lt = read_loan_type(contract_subtypes, field_buffer(fields[1], 0));
	n = atoi(field_buffer(fields[2], 0));
	yp = atoi(field_buffer(fields[3], 0));
	d = atoi(field_buffer(fields[4], 0));
	p = atof(field_buffer(fields[5], 0));
	r = atof(field_buffer(fields[6], 0));

	if (!n || !yp || (p <= 0.0)) return 0;

	//adapt wrt yearly payments
	if (yp > 1) {
		n = n*yp;
		d = d*yp;
		r = r/(double)yp;
	}

	/* setup pad */
	pad = newpad(n+1, WIDTH-2);

	/* run simulation */
	loan l = loan_init(lt, n, d, r, p);
	for (int i = 0; i <= n; i++) {
		print_contract(pad, i, 2, l.c);
		loan_update(l);
	}
	duration = n - HEIGHT + 6;

	return 1;
}

int min(int a, int b) {
	return (a < b) ? a : b;
}