#include <stdlib.h>
#include <stdint.h>
#include <assert.h>

#include "cmark_ctype.h"
#include "utf8.h"

static const int8_t utf8proc_utf8class[256] = {
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
	2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
	3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
	4, 4, 4, 4, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0
};

static void encode_unknown(cmark_strbuf *buf)
{
	static const uint8_t repl[] = {239, 191, 189};
	cmark_strbuf_put(buf, repl, 3);
}

static int utf8proc_charlen(const uint8_t *str, bufsize_t str_len)
{
	int length, i;

	if (!str_len)
		return 0;

	length = utf8proc_utf8class[str[0]];

	if (!length)
		return -1;

	if (str_len >= 0 && (bufsize_t)length > str_len)
		return -str_len;

	for (i = 1; i < length; i++) {
		if ((str[i] & 0xC0) != 0x80)
			return -i;
	}

	return length;
}

// Validate a single UTF-8 character according to RFC 3629.
static int utf8proc_valid(const uint8_t *str, bufsize_t str_len)
{
	int length = utf8proc_utf8class[str[0]];

	if (!length)
		return -1;

	if ((bufsize_t)length > str_len)
		return -str_len;

	switch (length) {
	case 2:
		if ((str[1] & 0xC0) != 0x80)
			return -1;
		if (str[0] < 0xC2) {
			// Overlong
			return -length;
		}
		break;

	case 3:
		if ((str[1] & 0xC0) != 0x80)
			return -1;
		if ((str[2] & 0xC0) != 0x80)
			return -2;
		if (str[0] == 0xE0) {
			if (str[1] < 0xA0) {
				// Overlong
				return -length;
			}
		} else if (str[0] == 0xED) {
			if (str[1] >= 0xA0) {
				// Surrogate
				return -length;
			}
		}
		break;

	case 4:
		if ((str[1] & 0xC0) != 0x80)
			return -1;
		if ((str[2] & 0xC0) != 0x80)
			return -2;
		if ((str[3] & 0xC0) != 0x80)
			return -3;
		if (str[0] == 0xF0) {
			if (str[1] < 0x90) {
				// Overlong
				return -length;
			}
		} else if (str[0] >= 0xF4) {
			if (str[0] > 0xF4 || str[1] >= 0x90) {
				// Above 0x10FFFF
				return -length;
			}
		}
		break;
	}

	return length;
}

void utf8proc_check(cmark_strbuf *ob, const uint8_t *line, bufsize_t size)
{
	bufsize_t i = 0;

	while (i < size) {
		bufsize_t org = i;
		int charlen = 0;

		while (i < size) {
			if (line[i] < 0x80 && line[i] != 0) {
				i++;
			} else if (line[i] >= 0x80) {
				charlen = utf8proc_valid(line + i, size - i);
				if (charlen < 0) {
					charlen = -charlen;
					break;
				}
				i += charlen;
			} else if (line[i] == 0) {
				// ASCII NUL is technically valid but rejected
				// for security reasons.
				charlen = 1;
				break;
			}
		}

		if (i > org) {
			cmark_strbuf_put(ob, line + org, i - org);
		}

		if (i >= size) {
			break;
		} else {
			// Invalid UTF-8
			encode_unknown(ob);
			i += charlen;
		}
	}
}

int utf8proc_iterate(const uint8_t *str, bufsize_t str_len, int32_t *dst)
{
	int length;
	int32_t uc = -1;

	*dst = -1;
	length = utf8proc_charlen(str, str_len);
	if (length < 0)
		return -1;

	switch (length) {
	case 1:
		uc = str[0];
		break;
	case 2:
		uc = ((str[0] & 0x1F) <<  6) + (str[1] & 0x3F);
		if (uc < 0x80) uc = -1;
		break;
	case 3:
		uc = ((str[0] & 0x0F) << 12) + ((str[1] & 0x3F) <<  6)
		     + (str[2] & 0x3F);
		if (uc < 0x800 || (uc >= 0xD800 && uc < 0xE000)) uc = -1;
		break;
	case 4:
		uc = ((str[0] & 0x07) << 18) + ((str[1] & 0x3F) << 12)
		     + ((str[2] & 0x3F) <<  6) + (str[3] & 0x3F);
		if (uc < 0x10000 || uc >= 0x110000) uc = -1;
		break;
	}

	if (uc < 0)
		return -1;

	*dst = uc;
	return length;
}

void utf8proc_encode_char(int32_t uc, cmark_strbuf *buf)
{
	uint8_t dst[4];
	bufsize_t len = 0;

	assert(uc >= 0);

	if (uc < 0x80) {
		dst[0] = uc;
		len = 1;
	} else if (uc < 0x800) {
		dst[0] = 0xC0 + (uc >> 6);
		dst[1] = 0x80 + (uc & 0x3F);
		len = 2;
	} else if (uc == 0xFFFF) {
		dst[0] = 0xFF;
		len = 1;
	} else if (uc == 0xFFFE) {
		dst[0] = 0xFE;
		len = 1;
	} else if (uc < 0x10000) {
		dst[0] = 0xE0 + (uc >> 12);
		dst[1] = 0x80 + ((uc >> 6) & 0x3F);
		dst[2] = 0x80 + (uc & 0x3F);
		len = 3;
	} else if (uc < 0x110000) {
		dst[0] = 0xF0 + (uc >> 18);
		dst[1] = 0x80 + ((uc >> 12) & 0x3F);
		dst[2] = 0x80 + ((uc >> 6) & 0x3F);
		dst[3] = 0x80 + (uc & 0x3F);
		len = 4;
	} else {
		encode_unknown(buf);
		return;
	}

	cmark_strbuf_put(buf, dst, len);
}

void utf8proc_case_fold(cmark_strbuf *dest, const uint8_t *str, bufsize_t len)
{
	int32_t c;

#define bufpush(x)				\
	utf8proc_encode_char(x, dest)

	while (len > 0) {
		bufsize_t char_len = utf8proc_iterate(str, len, &c);

		if (char_len >= 0) {
#include "case_fold_switch.inc"
		} else {
			encode_unknown(dest);
			char_len = -char_len;
		}

		str += char_len;
		len -= char_len;
	}
}

// matches anything in the Zs class, plus LF, CR, TAB, FF.
int utf8proc_is_space(int32_t uc)
{
	return (uc == 9 ||
	        uc == 10 ||
	        uc == 12 ||
	        uc == 13 ||
	        uc == 32 ||
	        uc == 160 ||
	        uc == 5760 ||
	        (uc >= 8192 && uc <= 8202) ||
	        uc == 8239 ||
	        uc == 8287 ||
	        uc == 12288);
}

// matches anything in the P[cdefios] classes.
int utf8proc_is_punctuation(int32_t uc)
{
	return ((uc < 128 && cmark_ispunct((char)uc)) ||
	        uc == 161 ||
	        uc == 167 ||
	        uc == 171 ||
	        uc == 182 ||
	        uc == 183 ||
	        uc == 187 ||
	        uc == 191 ||
	        uc == 894 ||
	        uc == 903 ||
	        (uc >= 1370 && uc <= 1375) ||
	        uc == 1417 ||
	        uc == 1418 ||
	        uc == 1470 ||
	        uc == 1472 ||
	        uc == 1475 ||
	        uc == 1478 ||
	        uc == 1523 ||
	        uc == 1524 ||
	        uc == 1545 ||
	        uc == 1546 ||
	        uc == 1548 ||
	        uc == 1549 ||
	        uc == 1563 ||
	        uc == 1566 ||
	        uc == 1567 ||
	        (uc >= 1642 && uc <= 1645) ||
	        uc == 1748 ||
	        (uc >= 1792 && uc <= 1805) ||
	        (uc >= 2039 && uc <= 2041) ||
	        (uc >= 2096 && uc <= 2110) ||
	        uc == 2142 ||
	        uc == 2404 ||
	        uc == 2405 ||
	        uc == 2416 ||
	        uc == 2800 ||
	        uc == 3572 ||
	        uc == 3663 ||
	        uc == 3674 ||
	        uc == 3675 ||
	        (uc >= 3844 && uc <= 3858) ||
	        uc == 3860 ||
	        (uc >= 3898 && uc <= 3901) ||
	        uc == 3973 ||
	        (uc >= 4048 && uc <= 4052) ||
	        uc == 4057 ||
	        uc == 4058 ||
	        (uc >= 4170 && uc <= 4175) ||
	        uc == 4347 ||
	        (uc >= 4960 && uc <= 4968) ||
	        uc == 5120 ||
	        uc == 5741 ||
	        uc == 5742 ||
	        uc == 5787 ||
	        uc == 5788 ||
	        (uc >= 5867 && uc <= 5869) ||
	        uc == 5941 ||
	        uc == 5942 ||
	        (uc >= 6100 && uc <= 6102) ||
	        (uc >= 6104 && uc <= 6106) ||
	        (uc >= 6144 && uc <= 6154) ||
	        uc == 6468 ||
	        uc == 6469 ||
	        uc == 6686 ||
	        uc == 6687 ||
	        (uc >= 6816 && uc <= 6822) ||
	        (uc >= 6824 && uc <= 6829) ||
	        (uc >= 7002 && uc <= 7008) ||
	        (uc >= 7164 && uc <= 7167) ||
	        (uc >= 7227 && uc <= 7231) ||
	        uc == 7294 ||
	        uc == 7295 ||
	        (uc >= 7360 && uc <= 7367) ||
	        uc == 7379 ||
	        (uc >= 8208 && uc <= 8231) ||
	        (uc >= 8240 && uc <= 8259) ||
	        (uc >= 8261 && uc <= 8273) ||
	        (uc >= 8275 && uc <= 8286) ||
	        uc == 8317 ||
	        uc == 8318 ||
	        uc == 8333 ||
	        uc == 8334 ||
	        (uc >= 8968 && uc <= 8971) ||
	        uc == 9001 ||
	        uc == 9002 ||
	        (uc >= 10088 && uc <= 10101) ||
	        uc == 10181 ||
	        uc == 10182 ||
	        (uc >= 10214 && uc <= 10223) ||
	        (uc >= 10627 && uc <= 10648) ||
	        (uc >= 10712 && uc <= 10715) ||
	        uc == 10748 ||
	        uc == 10749 ||
	        (uc >= 11513 && uc <= 11516) ||
	        uc == 11518 ||
	        uc == 11519 ||
	        uc == 11632 ||
	        (uc >= 11776 && uc <= 11822) ||
	        (uc >= 11824 && uc <= 11842) ||
	        (uc >= 12289 && uc <= 12291) ||
	        (uc >= 12296 && uc <= 12305) ||
	        (uc >= 12308 && uc <= 12319) ||
	        uc == 12336 ||
	        uc == 12349 ||
	        uc == 12448 ||
	        uc == 12539 ||
	        uc == 42238 ||
	        uc == 42239 ||
	        (uc >= 42509 && uc <= 42511) ||
	        uc == 42611 ||
	        uc == 42622 ||
	        (uc >= 42738 && uc <= 42743) ||
	        (uc >= 43124 && uc <= 43127) ||
	        uc == 43214 ||
	        uc == 43215 ||
	        (uc >= 43256 && uc <= 43258) ||
	        uc == 43310 ||
	        uc == 43311 ||
	        uc == 43359 ||
	        (uc >= 43457 && uc <= 43469) ||
	        uc == 43486 ||
	        uc == 43487 ||
	        (uc >= 43612 && uc <= 43615) ||
	        uc == 43742 ||
	        uc == 43743 ||
	        uc == 43760 ||
	        uc == 43761 ||
	        uc == 44011 ||
	        uc == 64830 ||
	        uc == 64831 ||
	        (uc >= 65040 && uc <= 65049) ||
	        (uc >= 65072 && uc <= 65106) ||
	        (uc >= 65108 && uc <= 65121) ||
	        uc == 65123 ||
	        uc == 65128 ||
	        uc == 65130 ||
	        uc == 65131 ||
	        (uc >= 65281 && uc <= 65283) ||
	        (uc >= 65285 && uc <= 65290) ||
	        (uc >= 65292 && uc <= 65295) ||
	        uc == 65306 ||
	        uc == 65307 ||
	        uc == 65311 ||
	        uc == 65312 ||
	        (uc >= 65339 && uc <= 65341) ||
	        uc == 65343 ||
	        uc == 65371 ||
	        uc == 65373 ||
	        (uc >= 65375 && uc <= 65381) ||
	        (uc >= 65792 && uc <= 65794) ||
	        uc == 66463 ||
	        uc == 66512 ||
	        uc == 66927 ||
	        uc == 67671 ||
	        uc == 67871 ||
	        uc == 67903 ||
	        (uc >= 68176 && uc <= 68184) ||
	        uc == 68223 ||
	        (uc >= 68336 && uc <= 68342) ||
	        (uc >= 68409 && uc <= 68415) ||
	        (uc >= 68505 && uc <= 68508) ||
	        (uc >= 69703 && uc <= 69709) ||
	        uc == 69819 ||
	        uc == 69820 ||
	        (uc >= 69822 && uc <= 69825) ||
	        (uc >= 69952 && uc <= 69955) ||
	        uc == 70004 ||
	        uc == 70005 ||
	        (uc >= 70085 && uc <= 70088) ||
	        uc == 70093 ||
	        (uc >= 70200 && uc <= 70205) ||
	        uc == 70854 ||
	        (uc >= 71105 && uc <= 71113) ||
	        (uc >= 71233 && uc <= 71235) ||
	        (uc >= 74864 && uc <= 74868) ||
	        uc == 92782 ||
	        uc == 92783 ||
	        uc == 92917 ||
	        (uc >= 92983 && uc <= 92987) ||
	        uc == 92996 ||
	        uc == 113823);
}