#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "btk-text.h"

/* mode for difference between backspace and del */
/* mode == 0 : backspace; mode == 1 : del */
int
btk_text_del_char(char *dest, int pos, int mode)
{
	int dest_n = strlen(dest);

	if (mode && !(dest_n - pos))
		return 0;
	if (!mode && !pos)
		return 0;

	for (int i = pos - 1 + mode; i < dest_n; i++)
		dest[i] = dest [i + 1];

	return 1;
}

int
btk_text_insert_char(char *dest, char src, int pos, int max_w)
{
	int dest_n = strlen(dest);

	if (dest_n >= max_w - 1)
		return 0;

	for (int i = dest_n; i >= pos; i--)
		dest[i + 1] = dest[i];
	dest[pos] = src;

	return 1;
}

/***************************************************************************************/

btk_pos_t
btk_text_caret_1dto2d(btk_par_t *par, int caret)
{
	int c = caret;
	btk_pos_t pos = {0, 0};

	if (caret <= 0)
		return pos;

	/* add previous rows qtt */
	for (int i = 0; i < par->rows_n; i++) {
		if (c >= par->rows_w[i]) {
			c -= par->rows_w[i];
		} else {
			pos.y = i;
			break;
		}
	}

	/* compensation for indentation at the beginning of row*/
	if (*(par->rows_shadow + pos.y * par->rows_max_w) == 's')
		while (*(par->rows_shadow + pos.y * par->rows_max_w + pos.x) == 's')
			pos.x++;

	/* add current row qtt */
	for (int i = 0; i < c; i++) {
		pos.x++;
		while (*(par->rows_shadow + pos.y * par->rows_max_w + pos.x) == 's')
			pos.x++;
	}

	return pos;
}

int
btk_text_caret_2dto1d(btk_par_t *par, btk_pos_t pos)
{
	int caret = 0;

	for (int i = 0; i < pos.y; i++)
		caret += par->rows_w[i];

	for (int i = 0; i < pos.x; i++)
		if (*(par->rows_shadow + pos.y * par->rows_max_w + i) != 's')
			caret++;
		
	return caret;
}

void
btk_text_destroy_par(btk_par_t *par)
{
	if (!par)
		return;

	free(par->rows);
	free(par->rows_shadow);
	free(par->rows_spot);
	free(par->rows_w);
	free(par);
}

btk_par_t*
btk_text_get_par(char *text, unsigned int rows_max_w)
{
	if (!text || !rows_max_w) {
		return NULL;
	}

	int text_n = strlen(text);
	int buffer_n = 1;

	btk_par_t *par   = malloc(sizeof(btk_par_t));
	par->rows_n      = 0;
	par->rows_max_w  = rows_max_w;
	par->rows        = malloc(buffer_n * rows_max_w);
	par->rows_shadow = malloc(buffer_n * rows_max_w);
	par->rows_spot   = malloc(buffer_n * sizeof(int));
	par->rows_w      = malloc(buffer_n * sizeof(int));

	par->rows_w[0] = 0;

	int pos = 0;
	int a = 0, b = 0;
	int first = 1;
	int indent = 0;
	int cl = 0, cr = 0;
	for (int i = 0;; i++) {

		/* set base row indentation level */
		if (!pos) {
			b = indent >= rows_max_w ? rows_max_w : indent;
			for (int j = 0; j < b; j++, pos++) {
				par->rows[pos + par->rows_n * rows_max_w] = ' ';
				par->rows_shadow[pos + par->rows_n * rows_max_w] = 's';
			}
		}
		
		par->rows_w[par->rows_n]++;
		switch(text[i]) {

		case '\0':
			par->rows[pos + par->rows_n * rows_max_w] = ' ';
			par->rows_shadow[pos + par->rows_n * rows_max_w] = 'e';
			pos++;
			cr = 1;
			goto row_end;

		case '\n':
			par->rows[pos + par->rows_n * rows_max_w] = ' ';
			par->rows_shadow[pos + par->rows_n * rows_max_w] = 'n';
			pos++;
			cr = 1;
			goto row_end;

		case '\t':
			par->rows[pos + par->rows_n * rows_max_w] = ' ';
			par->rows_shadow[pos + par->rows_n * rows_max_w] = 't';
			a = btk_tab_size - pos % (btk_tab_size);
			b = pos + a >= rows_max_w - 1 ? rows_max_w - 1 : pos + a;
			pos++;
			for (int j = pos; j < b; j++, pos++) {
				par->rows[pos + par->rows_n * rows_max_w] = ' ';
				par->rows_shadow[pos + par->rows_n * rows_max_w] = 's';
			}	
			if (first)
				indent += btk_tab_size;
			if (b == rows_max_w - 1)
				goto row_end;
			break;

		case '>':
			if (!first)
				goto char_input;
			cl = 1;
			par->rows[pos + par->rows_n * rows_max_w] = ' ';
			par->rows_shadow[pos + par->rows_n * rows_max_w] = '>';
			pos++;
			par->rows[pos + par->rows_n * rows_max_w] = ' ';
			par->rows_shadow[pos + par->rows_n * rows_max_w] = 's';
			pos++;
			par->rows[pos + par->rows_n * rows_max_w] = '>';
			par->rows_shadow[pos + par->rows_n * rows_max_w] = 's';
			pos++;
			par->rows[pos + par->rows_n * rows_max_w] = ' ';
			par->rows_shadow[pos + par->rows_n * rows_max_w] = 's';
			pos++;
			indent += 4;
			first = 0;
			break;

		case '-':
			if (!first)
				goto char_input;
			par->rows[pos + par->rows_n * rows_max_w] = ' ';
			par->rows_shadow[pos + par->rows_n * rows_max_w] = '-';
			pos++;
			par->rows[pos + par->rows_n * rows_max_w] = ' ';
			par->rows_shadow[pos + par->rows_n * rows_max_w] = 's';
			pos++;
			par->rows[pos + par->rows_n * rows_max_w] = '-';
			par->rows_shadow[pos + par->rows_n * rows_max_w] = 's';
			pos++;
			par->rows[pos + par->rows_n * rows_max_w] = ' ';
			par->rows_shadow[pos + par->rows_n * rows_max_w] = 's';
			pos++;
			indent += 4;
			first = 0;
			break;

		case '#':
			cl = first ? 2 : cl;
			goto char_input;

		case '!':
			cl = first ? 4 : cl;
			goto char_input;

		default:
char_input:
			par->rows[pos + par->rows_n * rows_max_w] = text[i];
			par->rows_shadow[pos + par->rows_n * rows_max_w] = '_';
			pos++;
			first = 0;
			break;
		}

		if (pos >= rows_max_w - 1 || i == text_n) {
row_end:
			par->rows[pos + par->rows_n * rows_max_w] = '\0';
			par->rows_shadow[pos + par->rows_n * rows_max_w] = '\0';
			par->rows_spot[par->rows_n] = cl;
			par->rows_n++;
			pos = 0;
			if (cr) {
				cr = 0;
				cl = 0;
				indent = 0;
				first = 1;
			}
			par->rows_w[par->rows_n] = 0;
			if (text[i] == '\0')
				break;
		}

		if (par->rows_n >= buffer_n - 1) {
			buffer_n += 1;
			par->rows        = realloc(par->rows, buffer_n * rows_max_w);
			par->rows_shadow = realloc(par->rows_shadow, buffer_n * rows_max_w);
			par->rows_spot   = realloc(par->rows_spot, buffer_n * sizeof(int));
			par->rows_w      = realloc(par->rows_w, buffer_n * sizeof(int));
		}
	}

	/*
	printf("%i rows :\n", par->rows_n);
	for (int i = 0; i < par->rows_n; i++)
		printf("row %i\n", par->rows_w[i]);
	printf("\n");
	*/

	return par;
}

int
btk_text_guard_1d_caret(char *text, int caret)
{
	int new_caret = caret;
	int text_n = strlen(text);

	if (new_caret < 0)
		new_caret = 0;
	if (new_caret > text_n)
		new_caret = text_n;

	return new_caret;
}


btk_pos_t
btk_text_guard_2d_caret(btk_par_t *par, btk_pos_t pos)
{
	btk_pos_t new_pos = pos;
	if (new_pos.y <= 0)
		new_pos.y = 0;
	if (new_pos.y >= par->rows_n)
		new_pos.y = par->rows_n - 1;

	if (new_pos.x < 0)
		new_pos.x = 0;
	if (new_pos.x > strlen(par->rows + new_pos.y * par->rows_max_w) - 1)
		new_pos.x = strlen(par->rows + new_pos.y * par->rows_max_w) - 1;
	/*if (new_pos.x > par->rows_w[new_pos.y] - 1)
		new_pos.x = par->rows_w[new_pos.y] - 1;*/
	while (*(par->rows_shadow + pos.y * par->rows_max_w + new_pos.x) == 's')
		new_pos.x++;

	return new_pos;
}