/*
    DeaDBeeF - ultimate music player for GNU/Linux systems with X11
    Copyright (C) 2009  Alexey Yakovenko

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

    utf8 code is based on Basic UTF-8 manipulation routines
    by Jeff Bezanson
    placed in the public domain Fall 2005
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <alloca.h>
#include "ctype.h"
#include "utf8.h"

static const uint32_t offsetsFromUTF8[6] = {
    0x00000000UL, 0x00003080UL, 0x000E2080UL,
    0x03C82080UL, 0xFA082080UL, 0x82082080UL
};

static const char trailingBytesForUTF8[256] = {
    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,
    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,
    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,
    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,
    2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, 3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5
};

/* conversions without error checking
   only works for valid UTF-8, i.e. no 5- or 6-byte sequences
   srcsz = source size in bytes, or -1 if 0-terminated
   sz = dest size in # of wide characters

   returns # characters converted
   dest will always be L'\0'-terminated, even if there isn't enough room
   for all the characters.
   if sz = srcsz+1 (i.e. 4*srcsz+4 bytes), there will always be enough space.
*/
int u8_toucs(uint32_t *dest, int32_t sz, const char *src, int32_t srcsz)
{
    uint32_t ch;
    const char *src_end = src + srcsz;
    int32_t nb;
    int32_t i=0;

    while (i < sz-1) {
        nb = trailingBytesForUTF8[(unsigned char)*src];
        if (srcsz == -1) {
            if (*src == 0)
                goto done_toucs;
        }
        else {
            if (src + nb >= src_end)
                goto done_toucs;
        }
        ch = 0;
        switch (nb) {
            /* these fall through deliberately */
        case 3: ch += (unsigned char)*src++; ch <<= 6;
        case 2: ch += (unsigned char)*src++; ch <<= 6;
        case 1: ch += (unsigned char)*src++; ch <<= 6;
        case 0: ch += (unsigned char)*src++;
        }
        ch -= offsetsFromUTF8[nb];
        dest[i++] = ch;
    }
 done_toucs:
    dest[i] = 0;
    return i;
}

/* srcsz = number of source characters, or -1 if 0-terminated
   sz = size of dest buffer in bytes

   returns # characters converted
   dest will only be '\0'-terminated if there is enough space. this is
   for consistency; imagine there are 2 bytes of space left, but the next
   character requires 3 bytes. in this case we could NUL-terminate, but in
   general we can't when there's insufficient space. therefore this function
   only NUL-terminates if all the characters fit, and there's space for
   the NUL as well.
   the destination string will never be bigger than the source string.
*/
int u8_toutf8(char *dest, int32_t sz, uint32_t *src, int32_t srcsz)
{
    uint32_t ch;
    int32_t i = 0;
    char *dest_end = dest + sz;

    while (srcsz<0 ? src[i]!=0 : i < srcsz) {
        ch = src[i];
        if (ch < 0x80) {
            if (dest >= dest_end)
                return i;
            *dest++ = (char)ch;
        }
        else if (ch < 0x800) {
            if (dest >= dest_end-1)
                return i;
            *dest++ = (ch>>6) | 0xC0;
            *dest++ = (ch & 0x3F) | 0x80;
        }
        else if (ch < 0x10000) {
            if (dest >= dest_end-2)
                return i;
            *dest++ = (ch>>12) | 0xE0;
            *dest++ = ((ch>>6) & 0x3F) | 0x80;
            *dest++ = (ch & 0x3F) | 0x80;
        }
        else if (ch < 0x200000) {
            if (dest >= dest_end-3)
                return i;
            *dest++ = (ch>>18) | 0xF0;
            *dest++ = ((ch>>12) & 0x3F) | 0x80;
            *dest++ = ((ch>>6) & 0x3F) | 0x80;
            *dest++ = (ch & 0x3F) | 0x80;
        }
        i++;
    }
    if (dest < dest_end)
        *dest = '\0';
    return i;
}

int u8_wc_toutf8(char *dest, wchar_t ch)
{
    if (ch < 0x80) {
        dest[0] = (char)ch;
        return 1;
    }
    if (ch < 0x800) {
        dest[0] = (ch>>6) | 0xC0;
        dest[1] = (ch & 0x3F) | 0x80;
        return 2;
    }
    if (ch < 0x10000) {
        dest[0] = (ch>>12) | 0xE0;
        dest[1] = ((ch>>6) & 0x3F) | 0x80;
        dest[2] = (ch & 0x3F) | 0x80;
        return 3;
    }
    if (ch < 0x200000) {
        dest[0] = (ch>>18) | 0xF0;
        dest[1] = ((ch>>12) & 0x3F) | 0x80;
        dest[2] = ((ch>>6) & 0x3F) | 0x80;
        dest[3] = (ch & 0x3F) | 0x80;
        return 4;
    }
    return 0;
}

/* charnum => byte offset */
int u8_offset(char *str, int32_t charnum)
{
    int32_t offs=0;

    while (charnum > 0 && str[offs]) {
        (void)(isutf(str[++offs]) || isutf(str[++offs]) ||
               isutf(str[++offs]) || ++offs);
        charnum--;
    }
    return offs;
}

/* byte offset => charnum */
int u8_charnum(char *s, int32_t offset)
{
    int32_t charnum = 0, offs=0;

    while (offs < offset && s[offs]) {
        (void)(isutf(s[++offs]) || isutf(s[++offs]) ||
               isutf(s[++offs]) || ++offs);
        charnum++;
    }
    return charnum;
}

/* number of characters */
int u8_strlen(char *s)
{
    int32_t count = 0;
    int32_t i = 0;

    while (u8_nextchar(s, &i) != 0)
        count++;

    return count;
}

/* reads the next utf-8 sequence out of a string, updating an index */
uint32_t u8_nextchar(const char *s, int32_t *i)
{
    uint32_t ch = 0;
    int32_t sz = 0;

    do {
        ch <<= 6;
        ch += (unsigned char)s[(*i)++];
        sz++;
    } while (s[*i] && !isutf(s[*i]));
    ch -= offsetsFromUTF8[sz-1];

    return ch;
}

void u8_inc(const char *s, int32_t *i)
{
    (void)(isutf(s[++(*i)]) || isutf(s[++(*i)]) ||
           isutf(s[++(*i)]) || ++(*i));
}

void u8_dec(const char *s, int32_t *i)
{
    (void)(isutf(s[--(*i)]) || isutf(s[--(*i)]) ||
           isutf(s[--(*i)]) || --(*i));
}

int octal_digit(char c)
{
    return (c >= '0' && c <= '7');
}

int hex_digit(char c)
{
    return ((c >= '0' && c <= '9') ||
            (c >= 'A' && c <= 'F') ||
            (c >= 'a' && c <= 'f'));
}

/* assumes that src points to the character after a backslash
   returns number of input characters processed */
int u8_read_escape_sequence(const char *str, uint32_t *dest)
{
    uint32_t ch;
    char digs[]="\0\0\0\0\0\0\0\0\0";
    int32_t dno=0, i=1;

    ch = (uint32_t)str[0];    /* take literal character */
    if (str[0] == 'n')
        ch = L'\n';
    else if (str[0] == 't')
        ch = L'\t';
    else if (str[0] == 'r')
        ch = L'\r';
    else if (str[0] == 'b')
        ch = L'\b';
    else if (str[0] == 'f')
        ch = L'\f';
    else if (str[0] == 'v')
        ch = L'\v';
    else if (str[0] == 'a')
        ch = L'\a';
    else if (octal_digit(str[0])) {
        i = 0;
        do {
            digs[dno++] = str[i++];
        } while (octal_digit(str[i]) && dno < 3);
        ch = strtol(digs, NULL, 8);
    }
    else if (str[0] == 'x') {
        while (hex_digit(str[i]) && dno < 2) {
            digs[dno++] = str[i++];
        }
        if (dno > 0)
            ch = strtol(digs, NULL, 16);
    }
    else if (str[0] == 'u') {
        while (hex_digit(str[i]) && dno < 4) {
            digs[dno++] = str[i++];
        }
        if (dno > 0)
            ch = strtol(digs, NULL, 16);
    }
    else if (str[0] == 'U') {
        while (hex_digit(str[i]) && dno < 8) {
            digs[dno++] = str[i++];
        }
        if (dno > 0)
            ch = strtol(digs, NULL, 16);
    }
    *dest = ch;

    return i;
}

// convert a string with literal \uxxxx or \Uxxxxxxxx characters to UTF-8
// example: u8_unescape(mybuf, 256, "hello\\u220e")
// note the double backslash is needed if called on a C string literal
int u8_unescape(char *buf, int32_t sz, const char *src)
{
    int32_t c=0, amt;
    uint32_t ch;
    char temp[4];

    while (*src && c < sz) {
        if (*src == '\\') {
            src++;
            amt = u8_read_escape_sequence(src, &ch);
        }
        else {
            ch = (uint32_t)*src;
            amt = 1;
        }
        src += amt;
        amt = u8_wc_toutf8(temp, ch);
        if (amt > sz-c)
            break;
        memcpy(&buf[c], temp, amt);
        c += amt;
    }
    if (c < sz)
        buf[c] = '\0';
    return c;
}

int u8_escape_wchar(char *buf, int32_t sz, uint32_t ch)
{
    if (ch == L'\n')
        return snprintf(buf, sz, "\\n");
    else if (ch == L'\t')
        return snprintf(buf, sz, "\\t");
    else if (ch == L'\r')
        return snprintf(buf, sz, "\\r");
    else if (ch == L'\b')
        return snprintf(buf, sz, "\\b");
    else if (ch == L'\f')
        return snprintf(buf, sz, "\\f");
    else if (ch == L'\v')
        return snprintf(buf, sz, "\\v");
    else if (ch == L'\a')
        return snprintf(buf, sz, "\\a");
    else if (ch == L'\\')
        return snprintf(buf, sz, "\\\\");
    else if (ch < 32 || ch == 0x7f)
        return snprintf(buf, sz, "\\x%hhX", (unsigned char)ch);
    else if (ch > 0xFFFF)
        return snprintf(buf, sz, "\\U%.8lX", (uint32_t)ch);
    else if (ch >= 0x80 && ch <= 0xFFFF)
        return snprintf(buf, sz, "\\u%.4hX", (unsigned short)ch);

    return snprintf(buf, sz, "%c", (char)ch);
}

int u8_escape(char *buf, int32_t sz, const char *src, int32_t escape_quotes)
{
    int32_t c=0, i=0, amt;

    while (src[i] && c < sz) {
        if (escape_quotes && src[i] == '"') {
            amt = snprintf(buf, sz - c, "\\\"");
            i++;
        }
        else {
            amt = u8_escape_wchar(buf, sz - c, u8_nextchar(src, &i));
        }
        c += amt;
        buf += amt;
    }
    if (c < sz)
        *buf = '\0';
    return c;
}

char *u8_strchr(char *s, uint32_t ch, int32_t *charn)
{
    int32_t i = 0, lasti=0;
    uint32_t c;

    *charn = 0;
    while (s[i]) {
        c = u8_nextchar(s, &i);
        if (c == ch) {
            return &s[lasti];
        }
        lasti = i;
        (*charn)++;
    }
    return NULL;
}

char *u8_memchr(char *s, uint32_t ch, size_t sz, int32_t *charn)
{
    int32_t i = 0, lasti=0;
    uint32_t c;
    int32_t csz;

    *charn = 0;
    while (i < sz) {
        c = csz = 0;
        do {
            c <<= 6;
            c += (unsigned char)s[i++];
            csz++;
        } while (i < sz && !isutf(s[i]));
        c -= offsetsFromUTF8[csz-1];

        if (c == ch) {
            return &s[lasti];
        }
        lasti = i;
        (*charn)++;
    }
    return NULL;
}

int u8_is_locale_utf8(char *locale)
{
    /* this code based on libutf8 */
    const char* cp = locale;

    for (; *cp != '\0' && *cp != '@' && *cp != '+' && *cp != ','; cp++) {
        if (*cp == '.') {
            const char* encoding = ++cp;
            for (; *cp != '\0' && *cp != '@' && *cp != '+' && *cp != ','; cp++)
                ;
            if ((cp-encoding == 5 && !strncmp(encoding, "UTF-8", 5))
                || (cp-encoding == 4 && !strncmp(encoding, "utf8", 4)))
                return 1; /* it's UTF-8 */
            break;
        }
    }
    return 0;
}

int u8_vprintf(char *fmt, va_list ap)
{
    int32_t cnt, sz=0;
    char *buf;
    uint32_t *wcs;

    sz = 512;
    buf = (char*)alloca(sz);
 try_print:
    cnt = vsnprintf(buf, sz, fmt, ap);
    if (cnt >= sz) {
        buf = (char*)alloca(cnt - sz + 1);
        sz = cnt + 1;
        goto try_print;
    }
    wcs = (uint32_t*)alloca((cnt+1) * sizeof(uint32_t));
    cnt = u8_toucs(wcs, cnt+1, buf, cnt);
    printf("%ls", (wchar_t*)wcs);
    return cnt;
}

int u8_printf(char *fmt, ...)
{
    int32_t cnt;
    va_list args;

    va_start(args, fmt);

    cnt = u8_vprintf(fmt, args);

    va_end(args);
    return cnt;
}

// adaptation of g_utf8_validate

#define UTF8_COMPUTE(Char, Mask, Len)                                         \
  if (Char < 128)                                                             \
    {                                                                         \
      Len = 1;                                                                \
      Mask = 0x7f;                                                            \
    }                                                                         \
  else if ((Char & 0xe0) == 0xc0)                                             \
    {                                                                         \
      Len = 2;                                                                \
      Mask = 0x1f;                                                            \
    }                                                                         \
  else if ((Char & 0xf0) == 0xe0)                                             \
    {                                                                         \
      Len = 3;                                                                \
      Mask = 0x0f;                                                            \
    }                                                                         \
  else if ((Char & 0xf8) == 0xf0)                                             \
    {                                                                         \
      Len = 4;                                                                \
      Mask = 0x07;                                                            \
    }                                                                         \
  else if ((Char & 0xfc) == 0xf8)                                             \
    {                                                                         \
      Len = 5;                                                                \
      Mask = 0x03;                                                            \
    }                                                                         \
  else if ((Char & 0xfe) == 0xfc)                                             \
    {                                                                         \
      Len = 6;                                                                \
      Mask = 0x01;                                                            \
    }                                                                         \
  else                                                                        \
    Len = -1;

#define UTF8_LENGTH(Char)              \
  ((Char) < 0x80 ? 1 :                 \
   ((Char) < 0x800 ? 2 :               \
    ((Char) < 0x10000 ? 3 :            \
     ((Char) < 0x200000 ? 4 :          \
      ((Char) < 0x4000000 ? 5 : 6)))))


#define UTF8_GET(Result, Chars, Count, Mask, Len)                             \
  (Result) = (Chars)[0] & (Mask);                                             \
  for ((Count) = 1; (Count) < (Len); ++(Count))                               \
    {                                                                         \
      if (((Chars)[(Count)] & 0xc0) != 0x80)                                  \
        {                                                                     \
          (Result) = -1;                                                      \
          break;                                                              \
        }                                                                     \
      (Result) <<= 6;                                                         \
      (Result) |= ((Chars)[(Count)] & 0x3f);                                  \
    }

#define UNICODE_VALID(Char)                   \
    ((Char) < 0x110000 &&                     \
     (((Char) & 0xFFFFF800) != 0xD800) &&     \
     ((Char) < 0xFDD0 || (Char) > 0xFDEF) &&  \
     ((Char) & 0xFFFE) != 0xFFFE)


int u8_valid (const char  *str,
        int max_len,
        const char **end)
{

    const char *p;

    if (!str) {
        return 0;
    }

    if (end)
        *end = str;

    p = str;

    while ((max_len < 0 || (p - str) < max_len) && *p)
    {
        int i, mask = 0, len;
        int32_t result;
        unsigned char c = (unsigned char) *p;

        UTF8_COMPUTE (c, mask, len);

        if (len == -1)
            break;

        /* check that the expected number of bytes exists in str */
        if (max_len >= 0 &&
                ((max_len - (p - str)) < len))
            break;

        UTF8_GET (result, p, i, mask, len);

        if (UTF8_LENGTH (result) != len) /* Check for overlong UTF-8 */
            break;

        if (result == (int32_t)-1)
            break;

        if (!UNICODE_VALID (result))
            break;

        p += len;
    }

    if (end)
        *end = p;

    /* See that we covered the entire length if a length was
     * passed in, or that we ended on a nul if not
     */
    if (max_len >= 0 &&
            p != (str + max_len))
        return 0;
    else if (max_len < 0 &&
            *p != '\0')
        return 0;
    else
        return 1;
}

static const char lowerchars[] = "záéíñóúüäöåæøàçèéêабвгдеёжзийклмнорпстуфхцчшщъыьэюя";
static const char upperchars[] = "ZÁÉÍÑÓÚÜÄÖÅÆØÀÇÈÉÊАБВГДЕЁЖЗИЙКЛМНОРПСТУФХЦЧШЩЪЫЬЭЮЯ";

int
u8_tolower (const signed char *c, int l, char *out) {
    if (*c > 0) {
        *out = tolower (*c);
        out[1] = 0;
        return 1;
    }
    else {
        for (int i = 0; i < sizeof (upperchars)-l; i++) {
            if (!memcmp (upperchars+i, c, l)) {
                // found!
                memcpy (out, lowerchars+i, l);
                out[l] = 0;
                return l;
            }
        }
        memcpy (out, c, l);
        out[l] = 0;
        return l;
    }
}

const char *
utfcasestr (const char *s1, const char *s2) {
#if 0 // small u8_tolower test
    while (*s2) {
        int32_t i = 0;
        u8_nextchar (s2, &i);
        const char *next = s2 + i;
        char lw[10];
        int l = u8_tolower (s2, next-s2, lw);
        s2 = next;
        fprintf (stderr, "%s", lw);
    }
    fprintf (stderr, "\n");
    return NULL;
#endif
    while (*s1) {
        const char *p1 = s1;
        const char *p2 = s2;
        while (*p2 && *p1) {
            int32_t i1 = 0;
            int32_t i2 = 0;
            char lw1[10];
            char lw2[10];
            const char *next;
            u8_nextchar (p1, &i1);
            u8_nextchar (p2, &i2);
            int l1 = u8_tolower (p1, i1, lw1);
            int l2 = u8_tolower (p2, i2, lw2);
            //fprintf (stderr, "comparing %s to %s\n", lw1, lw2);
            if (strcmp (lw1, lw2)) {
                //fprintf (stderr, "fail\n");
                break;
            }
            p1 += i1;
            p2 += i2;
        }
        if (*p2 == 0) {
            //fprintf (stderr, "%s found in %s\n", s2, s1);
            return p1;
        }
        int32_t i = 0;
        u8_nextchar (s1, &i);
        s1 += i;
    }
    return NULL;
}