/*
 * Copyright (c) 2014 Marc André Tanner <mat at brain-dump.org>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include <ctype.h>
#include <string.h>
#include "text-motions.h"
#include "text-util.h"
#include "util.h"

// TODO: specify this per file type?
int is_word_boundry(int c) {
	return ISASCII(c) && !(('0' <= c && c <= '9') ||
	         ('a' <= c && c <= 'z') ||
	         ('A' <= c && c <= 'Z') || c == '_');
}

size_t text_begin(Text *txt, size_t pos) {
	return 0;
}

size_t text_end(Text *txt, size_t pos) {
	return text_size(txt);
}

size_t text_char_next(Text *txt, size_t pos) {
	Iterator it = text_iterator_get(txt, pos);
	text_iterator_char_next(&it, NULL);
	return it.pos;
}

size_t text_char_prev(Text *txt, size_t pos) {
	Iterator it = text_iterator_get(txt, pos);
	text_iterator_char_prev(&it, NULL);
	return it.pos;
}

size_t text_find_next(Text *txt, size_t pos, const char *s) {
	if (!s)
		return pos;
	size_t len = strlen(s), matched = 0;
	Iterator it = text_iterator_get(txt, pos), sit;
	for (char c; matched < len && text_iterator_byte_get(&it, &c); ) {
		if (c == s[matched]) {
			if (matched == 0)
				sit = it;
			matched++;
		} else if (matched > 0) {
			it = sit;
			matched = 0;
		}
		text_iterator_byte_next(&it, NULL);
	}
	return matched == len ? it.pos - len : pos;
}

size_t text_find_prev(Text *txt, size_t pos, const char *s) {
	if (!s)
		return pos;
	size_t len = strlen(s), matched = len - 1;
	Iterator it = text_iterator_get(txt, pos), sit;
	if (len == 0)
		return pos;
	for (char c; text_iterator_byte_get(&it, &c); ) {
		if (c == s[matched]) {
			if (matched == 0)
				break;
			if (matched == len - 1)
				sit = it;
			matched--;
		} else if (matched < len - 1) {
			it = sit;
			matched = len - 1;
		}
		text_iterator_byte_prev(&it, NULL);
	}
	return matched == 0 ? it.pos : pos;
}

size_t text_line_prev(Text *txt, size_t pos) {
	char c;
	Iterator it = text_iterator_get(txt, pos);
	if (!text_iterator_byte_get(&it, &c))
		return pos;
	if (c == '\n')
		text_iterator_byte_prev(&it, &c);
	if (c == '\r')
		text_iterator_byte_prev(&it, &c);
	while (text_iterator_byte_get(&it, &c) && c != '\n')
		text_iterator_byte_prev(&it, NULL);
	if (text_iterator_byte_prev(&it, &c) && c != '\r')
		text_iterator_byte_next(&it, &c);
	return it.pos;
}

size_t text_line_begin(Text *txt, size_t pos) {
	char c;
	Iterator it = text_iterator_get(txt, pos);
	if (!text_iterator_byte_get(&it, &c))
		return pos;
	if (c == '\n')
		text_iterator_byte_prev(&it, &c);
	if (c == '\r')
		text_iterator_byte_prev(&it, &c);
	while (text_iterator_byte_get(&it, &c)) {
		if (c == '\n') {
			it.pos++;
			break;
		}
		text_iterator_byte_prev(&it, NULL);
	}
	return it.pos;
}

size_t text_line_start(Text *txt, size_t pos) {
	char c;
	Iterator it = text_iterator_get(txt, text_line_begin(txt, pos));
	while (text_iterator_byte_get(&it, &c) && c != '\n' && isspace(c))
		text_iterator_byte_next(&it, NULL);
	return it.pos;
}

size_t text_line_finish(Text *txt, size_t pos) {
	char c;
	Iterator it = text_iterator_get(txt, text_line_end(txt, pos));
	do text_iterator_char_prev(&it, NULL);
	while (text_iterator_byte_get(&it, &c) && c != '\n' && isspace(c));
	return it.pos;
}

size_t text_line_lastchar(Text *txt, size_t pos) {
	char c;
	Iterator it = text_iterator_get(txt, text_line_end(txt, pos));
	if (text_iterator_char_prev(&it, &c) && c == '\n')
		text_iterator_byte_next(&it, NULL);
	return it.pos;
}

size_t text_line_end(Text *txt, size_t pos) {
	char c;
	Iterator it = text_iterator_get(txt, pos);
	while (text_iterator_byte_get(&it, &c) && c != '\r' && c != '\n')
		text_iterator_byte_next(&it, NULL);
	return it.pos;
}

size_t text_line_next(Text *txt, size_t pos) {
	char c;
	Iterator it = text_iterator_get(txt, pos);
	while (text_iterator_byte_get(&it, &c) && c != '\n')
		text_iterator_byte_next(&it, NULL);
	text_iterator_byte_next(&it, NULL);
	return it.pos;
}

size_t text_line_offset(Text *txt, size_t pos, size_t off) {
	char c;
	size_t bol = text_line_begin(txt, pos);
	Iterator it = text_iterator_get(txt, bol);
	while (off-- > 0 && text_iterator_byte_get(&it, &c) && c != '\r' && c != '\n')
		text_iterator_byte_next(&it, NULL);
	return it.pos;
}

size_t text_line_char_set(Text *txt, size_t pos, int count) {
	char c;
	size_t bol = text_line_begin(txt, pos);
	Iterator it = text_iterator_get(txt, bol);
	while (count-- > 0 && text_iterator_byte_get(&it, &c) && c != '\r' && c != '\n')
		text_iterator_char_next(&it, NULL);
	return it.pos;
}

int text_line_char_get(Text *txt, size_t pos) {
	char c;
	int count = 0;
	size_t bol = text_line_begin(txt, pos);
	Iterator it = text_iterator_get(txt, bol);
	while (text_iterator_byte_get(&it, &c) && it.pos < pos && c != '\r' && c != '\n') {
		text_iterator_char_next(&it, NULL);
		count++;
	}
	return count;
}

size_t text_line_char_next(Text *txt, size_t pos) {
	char c;
	Iterator it = text_iterator_get(txt, pos);
	if (!text_iterator_byte_get(&it, &c) || c == '\r' || c == '\n')
		return pos;
	if (!text_iterator_char_next(&it, &c) || c == '\r' || c == '\n')
		return pos;
	return it.pos;
}

size_t text_line_char_prev(Text *txt, size_t pos) {
	char c;
	Iterator it = text_iterator_get(txt, pos);
	if (!text_iterator_char_prev(&it, &c) || c == '\n')
		return pos;
	return it.pos;
}

size_t text_line_up(Text *txt, size_t pos) {
	int count = text_line_char_get(txt, pos);
	size_t prev = text_line_prev(txt, pos);
	return text_line_char_set(txt, prev, count);
}

size_t text_line_down(Text *txt, size_t pos) {
	int count = text_line_char_get(txt, pos);
	size_t next = text_line_next(txt, pos);
	return text_line_char_set(txt, next, count);
}

size_t text_range_line_first(Text *txt, Filerange *r) {
	if (!text_range_valid(r))
		return EPOS;
	return r->start;
}

size_t text_range_line_last(Text *txt, Filerange *r) {
	if (!text_range_valid(r))
		return EPOS;
	size_t pos = text_line_begin(txt, r->end);
	if (pos == r->end) {
		/* range ends at a begin of a line, skip last line ending */
		pos = text_line_prev(txt, pos);
		pos = text_line_begin(txt, pos);
	}
	return r->start <= pos ? pos : r->start;
}

size_t text_range_line_next(Text *txt, Filerange *r, size_t pos) {
	if (!text_range_contains(r, pos))
		return EPOS;
	size_t newpos = text_line_next(txt, pos);
	return newpos != pos && newpos < r->end ? newpos : EPOS;
}

size_t text_range_line_prev(Text *txt, Filerange *r, size_t pos) {
	if (!text_range_contains(r, pos))
		return EPOS;
	size_t newpos = text_line_begin(txt, text_line_prev(txt, pos));
	return newpos != pos && r->start <= newpos ? newpos : EPOS;
}

static size_t text_customword_start_next(Text *txt, size_t pos, int (*isboundry)(int)) {
	char c;
	Iterator it = text_iterator_get(txt, pos);
	if (!text_iterator_byte_get(&it, &c))
		return pos;
	if (isboundry(c))
		while (isboundry(c) && !isspace(c) && text_iterator_char_next(&it, &c));
	else
		while (!isboundry(c) && text_iterator_char_next(&it, &c));
	while (isspace(c) && text_iterator_char_next(&it, &c));
	return it.pos;
}

static size_t text_customword_start_prev(Text *txt, size_t pos, int (*isboundry)(int)) {
	char c;
	Iterator it = text_iterator_get(txt, pos);
	while (text_iterator_char_prev(&it, &c) && isspace(c));
	if (isboundry(c))
		do pos = it.pos; while (text_iterator_char_prev(&it, &c) && isboundry(c) && !isspace(c));
	else
		do pos = it.pos; while (text_iterator_char_prev(&it, &c) && !isboundry(c));
	return pos;
}

static size_t text_customword_end_next(Text *txt, size_t pos, int (*isboundry)(int)) {
	char c;
	Iterator it = text_iterator_get(txt, pos);
	while (text_iterator_char_next(&it, &c) && isspace(c));
	if (isboundry(c))
		do pos = it.pos; while (text_iterator_char_next(&it, &c) && isboundry(c) && !isspace(c));
	else
		do pos = it.pos; while (text_iterator_char_next(&it, &c) && !isboundry(c));
	return pos;
}

static size_t text_customword_end_prev(Text *txt, size_t pos, int (*isboundry)(int)) {
	char c;
	Iterator it = text_iterator_get(txt, pos);
	if (!text_iterator_byte_get(&it, &c))
		return pos;
	if (isboundry(c))
		while (isboundry(c) && !isspace(c) && text_iterator_char_prev(&it, &c));
	else
		while (!isboundry(c) && text_iterator_char_prev(&it, &c));
	while (isspace(c) && text_iterator_char_prev(&it, &c));
	return it.pos;
}

size_t text_longword_end_next(Text *txt, size_t pos) {
	return text_customword_end_next(txt, pos, isspace);
}

size_t text_longword_end_prev(Text *txt, size_t pos) {
	return text_customword_end_prev(txt, pos, isspace);
}

size_t text_longword_start_next(Text *txt, size_t pos) {
	return text_customword_start_next(txt, pos, isspace);
}

size_t text_longword_start_prev(Text *txt, size_t pos) {
	return text_customword_start_prev(txt, pos, isspace);
}

size_t text_word_end_next(Text *txt, size_t pos) {
	return text_customword_end_next(txt, pos, is_word_boundry);
}

size_t text_word_end_prev(Text *txt, size_t pos) {
	return text_customword_end_prev(txt, pos, is_word_boundry);
}

size_t text_word_start_next(Text *txt, size_t pos) {
	return text_customword_start_next(txt, pos, is_word_boundry);
}

size_t text_word_start_prev(Text *txt, size_t pos) {
	return text_customword_start_prev(txt, pos, is_word_boundry);
}

static size_t text_paragraph_sentence_next(Text *txt, size_t pos, bool sentence) {
	char c;
	bool content = false, paragraph = false;
	Iterator it = text_iterator_get(txt, pos);
	while (text_iterator_byte_next(&it, &c)) {
		content |= !isspace(c);
		if (sentence && (c == '.' || c == '?' || c == '!') && text_iterator_byte_next(&it, &c) && isspace(c)) {
			if (c == '\n' && text_iterator_byte_next(&it, &c)) {
				if (c == '\r')
					text_iterator_byte_next(&it, &c);
			} else {
				while (text_iterator_byte_get(&it, &c) && c == ' ')
					text_iterator_byte_next(&it, NULL);
			}
			break;
		}
		if (c == '\n' && text_iterator_byte_next(&it, &c)) {
			if (c == '\r')
				text_iterator_byte_next(&it, &c);
			content |= !isspace(c);
			if (c == '\n')
				paragraph = true;
		}
		if (content && paragraph)
			break;
	}
	return it.pos;
}

static size_t text_paragraph_sentence_prev(Text *txt, size_t pos, bool sentence) {
	char prev, c;
	bool content = false, paragraph = false;

	Iterator it = text_iterator_get(txt, pos);
	if (!text_iterator_byte_get(&it, &prev))
		return pos;

	while (text_iterator_byte_prev(&it, &c)) {
		content |= !isspace(c) && c != '.' && c != '?' && c != '!';
		if (sentence && content && (c == '.' || c == '?' || c == '!') && isspace(prev)) {
			do text_iterator_byte_next(&it, NULL);
			while (text_iterator_byte_get(&it, &c) && isspace(c));
			break;
		}
		if (c == '\r')
			text_iterator_byte_prev(&it, &c);
		if (c == '\n' && text_iterator_byte_prev(&it, &c)) {
			content |= !isspace(c);
			if (c == '\r')
				text_iterator_byte_prev(&it, &c);
			if (c == '\n') {
				paragraph = true;
				if (content) {
					do text_iterator_byte_next(&it, NULL);
					while (text_iterator_byte_get(&it, &c) && isspace(c));
					break;
				}
			}
		}
		if (content && paragraph) {
			do text_iterator_byte_next(&it, NULL);
			while (text_iterator_byte_get(&it, &c) && !isspace(c));
			break;
		}
		prev = c;
	}
	return it.pos;
}

size_t text_sentence_next(Text *txt, size_t pos) {
	return text_paragraph_sentence_next(txt, pos, true);
}

size_t text_sentence_prev(Text *txt, size_t pos) {
	return text_paragraph_sentence_prev(txt, pos, true);
}

size_t text_paragraph_next(Text *txt, size_t pos) {
	return text_paragraph_sentence_next(txt, pos, false);
}

size_t text_paragraph_prev(Text *txt, size_t pos) {
	return text_paragraph_sentence_prev(txt, pos, false);
}

size_t text_line_empty_next(Text *txt, size_t pos) {
	// TODO refactor search \n\n
	char c;
	Iterator it = text_iterator_get(txt, pos);
	while (text_iterator_byte_get(&it, &c)) {
		if (c == '\n' && text_iterator_byte_next(&it, &c)) {
			size_t match = it.pos;
			if (c == '\r')
				text_iterator_byte_next(&it, &c);
			if (c == '\n')
				return match;
		}
		text_iterator_byte_next(&it, NULL);
	}
	return pos;
}

size_t text_line_empty_prev(Text *txt, size_t pos) {
	// TODO refactor search \n\n
	char c;
	Iterator it = text_iterator_get(txt, pos);
	while (text_iterator_byte_prev(&it, &c)) {
		if (c == '\n' && text_iterator_byte_prev(&it, &c)) {
			if (c == '\r')
				text_iterator_byte_prev(&it, &c);
			if (c == '\n')
				return it.pos + 1;
		}
	}
	return pos;
}

size_t text_function_start_next(Text *txt, size_t pos) {
	size_t a = text_function_end_next(txt, pos);
	size_t b = a;
	char c;
	if (a != pos) {
		Iterator it = text_iterator_get(txt, a);
		while (text_iterator_byte_next(&it, &c) && (c == '\r' || c == '\n'));
		a = it.pos;
	}
	if (b != pos) {
		size_t match = text_bracket_match(txt, b);
		b = match != b ? text_line_next(txt, text_line_empty_prev(txt, match)) : pos;
	}
	if (a <= pos && b <= pos)
		return pos;
	else if (a <= pos)
		return b;
	else if (b <= pos)
		return a;
	else
		return MIN(a, b);
}

size_t text_function_start_prev(Text *txt, size_t pos) {
	char c;
	size_t apos = text_byte_get(txt, pos, &c) && c == '}' && pos > 0 ? pos - 1 : pos;
	size_t a = text_function_end_next(txt, apos);
	size_t b = text_function_end_prev(txt, pos);
	if (a != apos) {
		size_t match = text_bracket_match(txt, a);
		a = match != a ? text_line_next(txt, text_line_empty_prev(txt, match)) : pos;
	}
	if (b != pos) {
		size_t match = text_bracket_match(txt, b);
		b = match != b ? text_line_next(txt, text_line_empty_prev(txt, match)) : pos;
	}
	if (a >= pos && b >= pos)
		return pos;
	else if (a >= pos)
		return b;
	else if (b >= pos)
		return a;
	else
		return MAX(a, b);
}

static size_t text_function_end_direction(Text *txt, size_t pos, int direction) {
	size_t start = pos, match;
	if (direction < 0 && pos > 0)
		pos--;
	for (;;) {
		char c[3];
		if (direction > 0)
			match = text_find_next(txt, pos, "\n}");
		else
			match = text_find_prev(txt, pos, "\n}");
		if (text_bytes_get(txt, match, sizeof c, c) != 3 || c[0] != '\n' || c[1] != '}')
			break;
		if (c[2] == '\r' || c[2] == '\n')
			return match+1;
		if (match == pos)
			match += direction;
		pos = match;
	}
	return start;
}

size_t text_function_end_next(Text *txt, size_t pos) {
	return text_function_end_direction(txt, pos, +1);
}

size_t text_function_end_prev(Text *txt, size_t pos) {
	return text_function_end_direction(txt, pos, -1);
}

size_t text_bracket_match(Text *txt, size_t pos) {
	return text_bracket_match_except(txt, pos, NULL);
}

size_t text_bracket_match_except(Text *txt, size_t pos, const char *except) {
	int direction, count = 1;
	char search, current, c;
	bool instring = false;
	Iterator it = text_iterator_get(txt, pos);
	if (!text_iterator_byte_get(&it, &current))
		return pos;
	if (except && memchr(except, current, strlen(except)))
		return pos;
	switch (current) {
	case '(': search = ')'; direction =  1; break;
	case ')': search = '('; direction = -1; break;
	case '{': search = '}'; direction =  1; break;
	case '}': search = '{'; direction = -1; break;
	case '[': search = ']'; direction =  1; break;
	case ']': search = '['; direction = -1; break;
	case '<': search = '>'; direction =  1; break;
	case '>': search = '<'; direction = -1; break;
	case '"':
	case '`':
	case '\'': {
		char special[] = " \n)}]>.,:;";
		search = current;
		direction = 1;
		if (text_iterator_byte_next(&it, &c)) {
			/* if a single or double quote is followed by
			 * a special character, search backwards */
			if (memchr(special, c, sizeof(special)))
				direction = -1;
			text_iterator_byte_prev(&it, NULL);
		}
		break;
	}
	default: return pos;
	}

	if (direction >= 0) { /* forward search */
		while (text_iterator_byte_next(&it, &c)) {
			if (c != current && (c == '"' || c == '\''))
				instring = !instring;
			if (!instring) {
				if (c == search && --count == 0)
					return it.pos;
				else if (c == current)
					count++;
			}
		}
	} else { /* backwards */
		while (text_iterator_byte_prev(&it, &c)) {
			if (c != current && (c == '"' || c == '\''))
				instring = !instring;
			if (!instring) {
				if (c == search && --count == 0)
					return it.pos;
				else if (c == current)
					count++;
			}
		}
	}

	return pos; /* no match found */
}

size_t text_search_forward(Text *txt, size_t pos, Regex *regex) {
	int start = pos + 1;
	int end = text_size(txt);
	RegexMatch match[1];
	bool found = !text_search_range_forward(txt, start, end - start, regex, 1, match, 0);

	if (!found) {
		start = 0;
		end = pos;
		found = !text_search_range_forward(txt, start, end, regex, 1, match, 0);
	}

	return found ? match[0].start : pos;
}

size_t text_search_backward(Text *txt, size_t pos, Regex *regex) {
	int start = 0;
	int end = pos;
	RegexMatch match[1];
	bool found = !text_search_range_backward(txt, start, end, regex, 1, match, 0);

	if (!found) {
		start = pos + 1;
		end = text_size(txt);
		found = !text_search_range_backward(txt, start, end - start, regex, 1, match, 0);
	}

	return found ? match[0].start : pos;
}