#include <string.h>
#include <ctype.h>
#include <assert.h>
#include "fnv_hash.h"

#include "ansi.h"
#include "cmsys.h"

#define CHAR_LOWER(c)  ((c >= 'A' && c <= 'Z') ? c|32 : c)
/* ----------------------------------------------------- */
/* 字串轉換檢查函數                                      */
/* ----------------------------------------------------- */
/**
 * 將字串 s 轉為小寫存回 t
 * @param t allocated char array
 * @param s
 */
void
str_lower(char *t, const char *s)
{
    register unsigned char ch;

    do {
	ch = *s++;
	*t++ = CHAR_LOWER(ch);
    } while (ch);
}

/**
 * 移除字串 buf 後端多餘的空白。
 * @param buf
 */
void
trim(char *buf)
{				/* remove trailing space */
    char           *p = buf;

    while (*p)
	p++;
    while (--p >= buf) {
	if (*p == ' ')
	    *p = '\0';
	else
	    break;
    }
}

/**
 * 移除 src 的 '\n' 並改成 '\0'
 * @param src
 */
void chomp(char *src)
{
    while(*src){
	if (*src == '\n')
	    *src = 0;
	else
	    src++;
    }
}

/* ----------------------------------------------------- */
/* ANSI 處理函數                                         */
/* ----------------------------------------------------- */
int
strip_blank(char *cbuf, const char *buf)
{
    for (; *buf; buf++)
	if (*buf != ' ')
	    *cbuf++ = *buf;
    *cbuf = 0;
    return 0;
}

static const char EscapeFlag[] = {
    /*  0 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    /* 10 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ,0, 0, 0, 0, 0,
    /* 20 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    /* 30 */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 0, /* 0~9 ;= */
    /* 40 */ 0, 2, 2, 2, 2, 0, 0, 0, 2, 2, 2, 2, 0, 0, 0, 0, /* ABCDHIJK */
    /* 50 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    /* 60 */ 0, 0, 0, 0, 0, 0, 2, 0, 2, 0, 0, 0, 2, 2, 0, 0, /* fhlm */
    /* 70 */ 0, 0, 0, 2, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* su */
    /* 80 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    /* 90 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    /* A0 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    /* B0 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    /* C0 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    /* D0 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    /* E0 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    /* F0 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
};
/**
 * 根據 mode 來 strip 字串 src，並把結果存到 dst
 * @param dst
 * @param src (if NULL then only return length)
 * @param mode enum {STRIP_ALL = 0, ONLY_COLOR, NO_RELOAD};
 *             STRIP_ALL:  全部吃掉
 *             ONLY_COLOR: 只留跟顏色有關的 (ESC[*m)
 *             NO_RELOAD:  只留上面認識的(移位+色彩)
 * @return strip 後的長度
 */
int
strip_ansi(char *dst, const char *src, enum STRIP_FLAG mode)
{
    register int    count = 0;
#define isEscapeParam(X) (EscapeFlag[(int)(X)] & 1)
#define isEscapeCommand(X) (EscapeFlag[(int)(X)] & 2)

    for(; *src; ++src)
	if( *src != ESC_CHR ){
	    if( dst )
		*dst++ = *src;
	    ++count;
	}else{
	    const char* p = src + 1;
	    if( *p != '[' ){
		++src;
		if(*src=='\0') break;
		continue;
	    }
	    while(isEscapeParam(*++p));
	    if( (mode == NO_RELOAD && isEscapeCommand(*p)) ||
		(mode == ONLY_COLOR && *p == 'm' )){
		register int len = p - src + 1;
		if( dst ){
		    memmove(dst, src, len);
		    dst += len;
		}
		count += len;
	    }
	    src = p;
	    if(*src=='\0') break;
	}
    if( dst )
	*dst = 0;
    return count;
}

/**
 * query the offset of nth non-ANSI element in s
 * if string is less then nth, return missing blanks in negative value.
 */
int 
strat_ansi(int count, const char *s)
{
    register int mode = 0;
    const char *os = s;

    for (; count > 0 && *s; ++s)
    {
	// 0 - no ansi, 1 - [, 2 - param+cmd
	switch (mode)
	{
	    case 0:
		if (*s == ESC_CHR)
		    mode = 1;
		else 
		    count --;
		break;

	    case 1:
		if (*s == '[')
		    mode = 2;
		else
		    mode = 0; // unknown command
		break;

	    case 2:
		if (isEscapeParam(*s))
		    continue;
		else if (isEscapeCommand(*s))
		    mode = 0;
		else
		    mode = 0;
		break;
	}
    }
    if (count > 0)
	return -count;
    return s - os;
}

int  
strlen_noansi(const char *s)
{
    // XXX this is almost identical to
    // strip_ansi(NULL, s, STRIP_ALL)
    register int count = 0, mode = 0;

    if (!s || !*s)
	return 0;

    for (; *s; ++s)
    {
	// 0 - no ansi, 1 - [, 2 - param+cmd
	switch (mode)
	{
	    case 0:
		if (*s == ESC_CHR)
		    mode = 1;
		else 
		    count ++;
		break;

	    case 1:
		if (*s == '[')
		    mode = 2;
		else
		    mode = 0; // unknown command
		break;

	    case 2:
		if (isEscapeParam(*s))
		    continue;
		else if (isEscapeCommand(*s))
		    mode = 0;
		else
		    mode = 0;
		break;
	}
    }
    return count;
}

/* ----------------------------------------------------- */
/* DBCS 處理函數                                         */
/* ----------------------------------------------------- */

void
strip_nonebig5(unsigned char *str, int maxlen)
{
  int i;
  int len=0;
  for(i=0;i<maxlen && str[i];i++) {
    if(32<=str[i] && str[i]<128)
      str[len++]=str[i];
    else if(str[i]==255) {
      if(i+1<maxlen)
	if(251<=str[i+1] && str[i+1]<=254) {
	  i++;
	  if(i+1<maxlen && str[i+1])
	    i++;
	}
      continue;
    } else if(str[i]&0x80) {
      if(i+1<maxlen)
	if((0x40<=str[i+1] && str[i+1]<=0x7e) ||
	   (0xa1<=str[i+1] && str[i+1]<=0xfe)) {
	  str[len++]=str[i];
	  str[len++]=str[i+1];
	  i++;
	}
    }
  }
  if(len<maxlen)
    str[len]='\0';
}

/**
 * DBCS_RemoveIntrEscape(buf, len): 去除 DBCS 一字雙色字。
 * (deprecated)
 */
int DBCS_RemoveIntrEscape(unsigned char *buf, int *len)
{
    register int isInAnsi = 0, isInDBCS = 0;
    int l = 0, i = 0, oldl, iansi = 0;

    if (len) l = *len; else l = strlen((const char*)buf);
    oldl = l;

    for (i = 0; i < l; i++)
    {
	if (buf[i] == ESC_CHR && !isInAnsi)
	{
	    // new escape
	    isInAnsi = 1;
	    iansi = i;
	    continue;
	} 

	// character
	if (isInAnsi)
	{
	    // closing ANSI section?
	    switch (isInAnsi)
	    {
	    case 1: // normal ANSI
		if (buf[i] == '[')
		    isInAnsi = 2;
		else
		    isInAnsi = 0; // unknown command
		break;

	    case 2:
		if (isEscapeParam(buf[i]))
		    break;
		else 
		    isInAnsi = 0;
		break;
	    }
	    if (isInAnsi == 0 && isInDBCS && i+1 < l)
	    {
		// interupting ANSI closed, let's modify the string
		int sz = i + 1 - iansi; // size to move
		memmove(buf+iansi, buf+i+1, l-i-1);
		l -= sz;
		i = iansi-1; // for the ++ in loop
	    }
	} else if (isInDBCS) {
	    // not ANSI but in DBCS. finished one char.
	    isInDBCS = 0;
	} else if (buf[i] >= 0x80) {
	    // DBCS lead.
	    isInDBCS = 1;
	} else {
	    // normal character.
	}
    }

    if(len) *len = l;
    return (oldl != l) ? 1 : 0;
}

/**
 * DBCS_Status(dbcstr, pos): 取得字串中指定位置的 DBCS 狀態。
 */
int DBCS_Status(const char *dbcstr, int pos)
{
    int sts = DBCS_ASCII;
    const unsigned char *s = (const unsigned char*)dbcstr;

    while(pos >= 0)
    {
	if(sts == DBCS_LEADING)
	    sts = DBCS_TRAILING;
	else if (*s >= 0x80)
	{
	    sts = DBCS_LEADING;
	} else {
	    sts = DBCS_ASCII;
	}
	s++, pos--;
    }
    return sts;
}

/**
 * DBCS_strcasestr(pool, ptr): 在字串 pool 中尋找 ptr (只忽略英文大小寫)
 */
char *
DBCS_strcasestr(const char* pool, const char *ptr)
{
    int i = 0, i2 = 0, found = 0,
        szpool = strlen(pool),
        szptr  = strlen(ptr);

    for (i = 0; i <= szpool-szptr; i++)
    {
        found = 1;

        // compare szpool[i..szptr] with ptr
        for (i2 = 0; i2 < szptr; i2++)
        {
            if (pool[i + i2] > 0)
            {
                // ascii
                if (ptr[i2] < 0 || 
		    tolower(ptr[i2]) != tolower(pool[i+i2]))
                {
		    // printf("break on ascii (i=%d, i2=%d).\n", i, i2);
                    found = 0;
                    break;
                }
            } else {
                // non-ascii
                if (ptr[i2]   != pool[i+i2] ||
                    ptr[i2+1] != pool[i+i2+1])
                {
		    // printf("break on non-ascii (i=%d, i2=%d).\n", i, i2);
                    found = 0;
                    break;
                }
		i2 ++;
            }
        }

        if (found) 
	    return (char *)pool+i;

        // next iteration: if target is DBCS, skip one more byte.
        if (pool[i] < 0)
            i++;
    }
    return NULL;
}

/* ----------------------------------------------------- */
/* 字串檢查函數：英文、數字、檔名、E-mail address        */
/* ----------------------------------------------------- */

int
invalid_pname(const char *str)
{
    const char           *p1, *p2, *p3;

    p1 = str;
    while (*p1) {
	if (!(p2 = strchr(p1, '/')))
	    p2 = str + strlen(str);
	if (p1 + 1 > p2 || p1 + strspn(p1, ".") == p2) /* 不允許用 / 開頭, 或是 // 之間只有 . */
	    return 1;
	for (p3 = p1; p3 < p2; p3++)
	    if (!isalnum(*p3) && !strchr("@[]-._", *p3)) /* 只允許 alnum 或這些符號 */
		return 1;
	p1 = p2 + (*p2 ? 1 : 0);
    }
    return 0;
}

/*
 * return	1	if /^[0-9]+$/
 * 		0	else, 含空字串
 */
int is_number(const char *p)
{
    if (*p == '\0')
	return 0;

    for(; *p; p++) {
	if (*p < '0' || '9' < *p)
	    return 0;
    }
    return 1;
}

unsigned
StringHash(const char *s)
{
    return fnv1a_32_strcase(s, FNV1_32_INIT);
}

/* qp_encode() modified from mutt-1.5.7/rfc2047.c q_encoder() */
const char MimeSpecials[] = "@.,;:<>[]\\\"()?/= \t";
char * qp_encode (char *s, size_t slen, const char *d, const char *tocode)
{
    char hex[] = "0123456789ABCDEF";
    char *s0 = s;

    memcpy (s, "=?", 2), s += 2;
    memcpy (s, tocode, strlen (tocode)), s += strlen (tocode);
    memcpy (s, "?Q?", 3), s += 3;
    assert(s-s0+3<slen);

    while (*d != '\0' && s-s0+6<slen)
    {
	unsigned char c = *d++;
	if (c == ' ')
	    *s++ = '_';
	else if (c >= 0x7f || c < 0x20 || c == '_' ||  strchr (MimeSpecials, c))
	{ 
	    *s++ = '=';
	    *s++ = hex[(c & 0xf0) >> 4];
	    *s++ = hex[c & 0x0f];
	}
	else
	    *s++ = c;
    }
    memcpy (s, "?=", 2), s += 2;
    *s='\0';
    return s0;
}

// following code is moved from innbbsd/str_decode.c
/*-------------------------------------------------------*/
/* lib/str_decode.c    ( NTHU CS MapleBBS Ver 3.00 )    */
/*-------------------------------------------------------*/
/* target : included C for QP/BASE64 decoding           */
/* create : 95/03/29                                    */
/* update : 97/03/29                                    */
/*-------------------------------------------------------*/
#include <errno.h>
#include <iconv.h>


/* ----------------------------------------------------- */
/* QP code : "0123456789ABCDEF"                                 */
/* ----------------------------------------------------- */

static int 
qp_code(int x)
{
    if (x >= '0' && x <= '9')
	return x - '0';
    if (x >= 'a' && x <= 'f')
	return x - 'a' + 10;
    if (x >= 'A' && x <= 'F')
	return x - 'A' + 10;
    return -1;
}


/* ------------------------------------------------------------------ */
/* BASE64 :							      */
/* "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" */
/* ------------------------------------------------------------------ */

static int 
base64_code(int x)
{
    if (x >= 'A' && x <= 'Z')
	return x - 'A';
    if (x >= 'a' && x <= 'z')
	return x - 'a' + 26;
    if (x >= '0' && x <= '9')
	return x - '0' + 52;
    if (x == '+')
	return 62;
    if (x == '/')
	return 63;
    return -1;
}


/* ----------------------------------------------------- */
/* judge & decode QP / BASE64				 */
/* ----------------------------------------------------- */

static inline int 
isreturn(unsigned char c)
{
    return c == '\r' || c == '\n';
}

static inline
int 
mmdecode(unsigned char *src, unsigned char encode, unsigned char *dst)
{
    /* Thor.980901: src和dst可相同, 但src 一定有?或\0結束 */
    /* Thor.980901: 注意, decode出的結果不會自己加上 \0 */
    unsigned char  *t = dst;
    int             pattern = 0, bits = 0;
    encode |= 0x20;		/* Thor: to lower */
    switch (encode) {
    case 'q':			/* Thor: quoted-printable */
	while (*src && *src != '?') {	/* Thor: delimiter *//* Thor.980901:
					 * 0 算是 delimiter */
	    if (*src == '=') {
		int             x = *++src, y = x ? *++src : 0;
		if (isreturn(x))
		    continue;
		if ((x = qp_code(x)) < 0 || (y = qp_code(y)) < 0)
		    return -1;
		*t++ = (x << 4) + y, src++;
	    } else if (*src == '_')
		*t++ = ' ', src++;
#if 0
	    else if (!*src)	/* Thor: no delimiter is not successful */
		return -1;
#endif
	    else		/* Thor: *src != '=' '_' */
		*t++ = *src++;
	}
	return t - dst;
    case 'b':			/* Thor: base 64 */
	while (*src && *src != '?') {	/* Thor: delimiter */
	    /*
	     * Thor.980901: 0也算 *//* Thor: pattern & bits are cleared
	     * outside
	     */
	    int             x;
#if 0
	    if (!*src)
		return -1;	/* Thor: no delimiter is not successful */
#endif
	    x = base64_code(*src++);
	    if (x < 0)
		continue;	/* Thor: ignore everything not in the
				 * base64,=,.. */
	    pattern = (pattern << 6) | x;
	    bits += 6;		/* Thor: 1 code gains 6 bits */
	    if (bits >= 8) {	/* Thor: enough to form a byte */
		bits -= 8;
		*t++ = (pattern >> bits) & 0xff;
	    }
	}
	return t - dst;
    }
    return -1;
}

size_t 
str_iconv(
	  const char *fromcode,	/* charset of source string */
	  const char *tocode,	/* charset of destination string */
	  const char *src,	/* source string */
	  size_t srclen,		/* source string length */
	  char *dst,		/* destination string */
	  size_t dstlen)
{				/* destination string length */
    /*
     * 這個函式會將一個字串 (src) 從 charset=fromcode 轉成 charset=tocode,
     * srclen 是 src 的長度, dst 是輸出的buffer, dstlen 則指定了 dst 的大小,
     * 最後會補 '\0', 所以要留一個byte給'\0'. 如果遇到 src 中有非字集的字,
     * 或是 src 中有未完整的 byte, 都會砍掉.
     */
    iconv_t         iconv_descriptor;
    size_t          iconv_ret, dstlen_old;

    dstlen--;			/* keep space for '\0' */

    dstlen_old = dstlen;

    /* Open a descriptor for iconv */
    iconv_descriptor = iconv_open(tocode, fromcode);

    if (iconv_descriptor == ((iconv_t) (-1))) {	/* if open fail */
	strncpy(dst, src, dstlen);
	return dstlen;
    }
    /* Start translation */
    while (srclen > 0 && dstlen > 0) {
	iconv_ret = iconv(iconv_descriptor, &src, &srclen,
			  &dst, &dstlen);
	if (iconv_ret != 0) {
	    switch (errno) {
		/* invalid multibyte happened */
	    case EILSEQ:
		/* forward that byte */
		*dst = *src;
		src++;
		srclen--;
		dst++;
		dstlen--;
		break;
		/* incomplete multibyte happened */
	    case EINVAL:
		/* forward that byte (maybe wrong) */
		*dst = *src;
		src++;
		srclen--;
		dst++;
		dstlen--;
		break;
		/* dst no rooms */
	    case E2BIG:
		/* break out the while loop */
		srclen = 0;
		break;
	    }
	}
    }
    *dst = '\0';
    /* close descriptor of iconv */
    iconv_close(iconv_descriptor);

    return (dstlen_old - dstlen);
}


/**
 * inplace decode mime header string (rfc2047) to big5 encoding
 *
 * @param str	[in,out] string, output size is limited to 512. Assume output size is shorter than input size.
 *
 * TODO rewrite, don't hardcode 512
 */
void 
str_decode_M3(char *str)
{
    int             adj;
    int             i;
    unsigned char  *src, *dst;
    unsigned char   buf[512];
    unsigned char   charset[512], dst1[512];


    src = (unsigned char*)str;
    dst = buf;
    adj = 0;

    while (*src && (dst - buf) < sizeof(buf) - 1) {
	if (*src != '=') {	/* Thor: not coded */
	    unsigned char  *tmp = src;
	    while (adj && *tmp && isspace(*tmp))
		tmp++;
	    if (adj && *tmp == '=') {	/* Thor: jump over space */
		adj = 0;
		src = tmp;
	    } else
		*dst++ = *src++;
	    /* continue; *//* Thor: take out */
	} else {		/* Thor: *src == '=' */
	    unsigned char  *tmp = src + 1;
	    if (*tmp == '?') {	/* Thor: =? coded */
		/* "=?%s?Q?" for QP, "=?%s?B?" for BASE64 */
		tmp++;
		i = 0;
		while (*tmp && *tmp != '?') {
		    if (i + 1 < sizeof(charset)) {
			charset[i] = *tmp;
			charset[i + 1] = '\0';
			i++;
		    }
		    tmp++;
		}
		if (*tmp && tmp[1] && tmp[2] == '?') {	/* Thor: *tmp == '?' */
		    int             i = mmdecode(tmp + 3, tmp[1], dst1);
		    i = str_iconv((char*)charset, "big5", (char*)dst1, i, (char*)dst,
				  sizeof(buf) - ((int)(dst - buf)));
		    if (i >= 0) {
			tmp += 3;	/* Thor: decode's src */
#if 0
			while (*tmp++ != '?');	/* Thor: no ? end, mmdecode
						 * -1 */
#endif
			while (*tmp && *tmp++ != '?');	/* Thor: no ? end,
							 * mmdecode -1 */
			/* Thor.980901: 0 也算 decode 結束 */
			if (*tmp == '=')
			    tmp++;
			src = tmp;	/* Thor: decode over */
			dst += i;
			adj = 1;/* Thor: adjcent */
		    }
		}
	    }
	    while (src != tmp)	/* Thor: not coded */
		*dst++ = *src++;
	}
    }
    *dst = 0;
    assert(strlen(str) >= strlen((char*)buf));
    strcpy(str, (char*)buf);
}