/* xmenu
 * a simple fuzzy-selection menu made with Xlib
 */

#include <err.h>
#include <stdio.h>
#include <sys/stat.h>

#define ARENA_IMPL
#define STR_IMPL

#include "arena.h"
#include "dynarr.h"
#include "str.h"
#include "ui.h"
#include "fuzzy.h"

typedef DYNARR(char) DynStr;

int
umod(int a, int b)
{
	if (a < 0) {
		return b + a % b;
	} else {
		return a % b;
	}
}

int
txt_insert(DynStr *s, int i, Str ins)
{
	DA_FIT(s, s->n + ins.n);
	if (i < s->n) {
		memmove(s->v + i + ins.n, s->v + i, s->n - i);
	}
	memcpy(s->v + i, ins.s, ins.n);
	s->n += ins.n;
	return i + ins.n;
}

int
txt_delete_byte(DynStr *s, int i, int n)
{
	if (n > i) n = i;
	if (n > 0) {
		memmove(s->v + i - n, s->v + i, s->n - i);
		s->n -= n;
	}
	return i - n;
}

int
txt_delete(DynStr *s, int i, int n)
{
	while (n--) {
		i = txt_delete_byte(s, i, 1);
		while (i > 0 && (s->v[i-1] & 0x80))
			i = txt_delete_byte(s, i, 1);
	}
	return i;
}

int
delete_word(DynStr *s, int i)
{
	while (i > 0 && is_space(s->v[i-1]))
		i = txt_delete(s, i, 1);
	while (i > 0 && !is_space(s->v[i-1]))
		i = txt_delete(s, i, 1);
	return i;
}

int
prev_word(DynStr *s, int i)
{
	while (i > 0 && is_space(s->v[i-1]))
		i--;
	while (i > 0 && !is_space(s->v[i-1]))
		i--;
	return i;
}

int
next_word(DynStr *s, int i)
{
	while (i < s->n && is_space(s->v[i]))
		i++;
	while (i < s->n && !is_space(s->v[i]))
		i++;
	return i;
}

int
read_all(FILE *f, DynStr *out, Arena *a)
{
	char buf[256];
	while (!feof(f)) {
		size_t n = fread(buf, 1, sizeof buf, f);
		if (ferror(f)) return -1;
		DA_APUSH_MULT(out, a, buf, n);
	}
	return 0;
}

int
main(int argc, char **argv)
{
	Arena perm = { 0 };
	Arena scratch = { 0 };
	DynStr input = { 0 };
	int inpi = 0;
	int seli = 0;

	UiOpts opt_src = { 0 };
	DynStr buf = { 0 };
	if (read_all(stdin, &buf, &perm)) err(1, "stdin");
	for (Str src = { buf.v, buf.n }; src.n > 0; ) {
		Cut c = str_cut(src, '\n');
		DA_APUSH(&opt_src, &perm, c.head);
		src = c.tail;
	}

	if (!opt_src.n) return 0;

	UiOpts opt = {
		.v = new_arr(&perm, Str, opt_src.n),
		.n = opt_src.n,
	};

	ui_init(argc, argv, opt_src);
	DA_FIT(&input, 32);

	for (UiEvent ev; ui_wait_event(&ev); ) {
		switch (ev.type) {
		case UI_KEY_DOWN:
			switch (ev.key.key) {
			case UIK_ESCAPE:
				goto done;
			case UIK_BACKSPACE:
				if (ev.key.mod & UIM_CTRL) {
					inpi = delete_word(&input, inpi);
				} else {
					inpi = txt_delete(&input, inpi, 1);
				}
				goto chg;
			case UIK_RETURN: {
				Str o = opt.v[seli];
				printf("%.*s\n", (int)o.n, o.s);
			} goto done;
			case UIK_DOWN:
				seli = umod(seli + 1, opt.n);
				goto draw;
			case UIK_UP:
				seli = umod(seli - 1, opt.n);
				goto draw;
			case UIK_PGDN:
				seli += 8;
				if (seli >= opt.n) seli = opt.n - 1;
				goto draw;
			case UIK_PGUP:
				seli -= 8;
				if (seli < 0) seli = 0;
				goto draw;
			case UIK_LEFT:
				if (ev.key.mod & UIM_CTRL)
					inpi = prev_word(&input, inpi);
				else if (inpi > 0)
					inpi--;
				goto draw;
			case UIK_RIGHT:
				if (ev.key.mod & UIM_CTRL)
					inpi = next_word(&input, inpi);
				else if (inpi < input.n)
					inpi++;
				goto draw;
			case UIK_HOME:
				if (ev.key.mod & UIM_CTRL)
					seli = 0;
				else
					inpi = 0;
				goto draw;
			case UIK_END:
				if (ev.key.mod & UIM_CTRL)
					seli = opt.n - 1;
				else
					inpi = input.n;
				goto draw;
			default:
				if (!ev.key.strn) break;
				/* ^W */
				if (ev.key.strn == 1 && ev.key.str[0] == 0x17) {
					inpi = delete_word(&input, inpi);
					goto chg;
				}
				inpi = txt_insert(&input, inpi,
					(Str) { ev.key.str, ev.key.strn });
			chg:
				seli = 0;
				goto draw;
			}
			break;
		case UI_REDRAW:
		draw: {
			Str s = { input.v, input.n };
			opt.n = fz_sort(opt.v, opt_src.v, opt_src.n, s, &scratch);
			ui_draw(s, inpi, seli, opt);
		} break;
		case UI_QUIT:
			goto done;
		default:
			break;
		}
	}

done:
	ui_fini();
	arena_free(&perm);
	arena_free(&scratch);
	return 0;
}