/*
 * NNChat - Custom chat client for NewbieNudes.com chatrooms
 * Written by Matti 'ccr' Hämäläinen
 * (C) Copyright 2008-2012 Tecnic Software productions (TNSP)
 */
#include "util.h"


#define PUSHCHAR(x) th_vputch(&result, &resSize, &resPos, x)
#define PUSHSTR(x) th_vputs(&result, &resSize, &resPos, x)

char *nn_encode_str1(const char *str)
{
    const char *s = str;
    char *result;
    size_t resSize, resPos = 0;

    if (str == NULL) return NULL;

    resSize = strlen(str) + NN_ALLOC_SIZE;
    if ((result = th_malloc(resSize)) == NULL)
        return NULL;

    while (*s)
    {
        switch (*s)
        {
        case 32:
            PUSHCHAR('+');
            break;

        default:
            if (th_isalnum(*s))
                PUSHCHAR(*s);
            else
            {
                char tmpStr[4];
                snprintf(tmpStr, sizeof(tmpStr), "%2X", (unsigned char) *s);
                PUSHCHAR('%');
                PUSHSTR(tmpStr);
            }
            break;
        }
        s++;
    }
    PUSHCHAR(0);

    return result;
}


static int nn_get_hexdigit(const int c, const int shift)
{
    int i;

    if (c >= 'A' && c <= 'F')
        i = c - 'A' + 10;
    else if (c >= 'a' && c <= 'f')
        i = c - 'a' + 10;
    else if (c >= '0' && c <= '9')
        i = c - '0';
    else
        return -1;

    return i << shift;
}


char *nn_decode_str1(const char *str)
{
    const char *s = str;
    char *result;
    size_t resSize, resPos = 0;
    int c;

    if (str == NULL) return NULL;

    resSize = strlen(str) + NN_ALLOC_SIZE;
    if ((result = th_malloc(resSize)) == NULL)
        return NULL;

    while (*s)
    {
        switch (*s)
        {
        case '+':
            PUSHCHAR(' ');
            s++;
            break;

        case '½':
            /* Escape these .. */
            PUSHCHAR('½');
            PUSHCHAR('½');
            s++;
            break;

        case '\r':
            PUSHCHAR(' ');
            s++;
            break;

        case '%':
            s++;
            if (*s == '%')
                PUSHCHAR('%');
            else if ((c = nn_get_hexdigit(*s, 4)) >= 0)
            {
                int i = nn_get_hexdigit(*(++s), 0);
                if (i >= 0)
                {
                    PUSHCHAR(c | i);
                }
                else
                {
                    PUSHCHAR('§');
                    PUSHCHAR(*s);
                }
            }
            else
            {
                PUSHCHAR('§');
                PUSHCHAR(*s);
            }
            s++;
            break;

        default:
            PUSHCHAR(*s);
            s++;
        }
    }
    PUSHCHAR(0);

    return result;
}


char *nn_strip_tags(const char *str)
{
    const char *s = str;
    char *result;
    size_t resSize, resPos = 0;

    if (str == NULL) return NULL;

    resSize = strlen(str) + NN_ALLOC_SIZE;
    if ((result = th_malloc(resSize)) == NULL)
        return NULL;

    while (*s)
    {
        if (*s == '<')
        {
            while (*s && *s != '>') s++;
            if (*s == '>') s++;
        }
        else
            PUSHCHAR(*s++);
    }
    PUSHCHAR(0);

    return result;
}


typedef struct
{
    char c;
    char *ent;
} html_entity_t;


static const html_entity_t HTMLEntities[] =
{
    { '<', "&lt;" },
    { '>', "&gt;" },
};

static const int numHTMLEntities = sizeof(HTMLEntities) / sizeof(HTMLEntities[0]);


char *nn_encode_str2(const char *str)
{
    const char *s = str;
    char *result;
    size_t resSize, resPos = 0;

    if (str == NULL) return NULL;

    resSize = strlen(str) + NN_ALLOC_SIZE;
    if ((result = th_malloc(resSize)) == NULL)
        return NULL;

    while (*s)
    {
        int i;
        BOOL found = FALSE;
        for (i = 0; i < numHTMLEntities; i++)
            if (HTMLEntities[i].c == *s)
            {
                PUSHSTR(HTMLEntities[i].ent);
                found = TRUE;
                break;
            }
        if (!found) PUSHCHAR(*s);

        s++;
    }
    PUSHCHAR(0);

    return result;
}


char *nn_decode_str2(const char *str)
{
    const char *s = str;
    char *result;
    size_t resSize, resPos = 0;

    if (str == NULL) return NULL;

    resSize = strlen(str);
    if ((result = th_malloc(resSize)) == NULL)
        return NULL;

    while (*s)
    {
        if (*s == '&')
        {
            int i;
            BOOL found = FALSE;
            for (i = 0; i < numHTMLEntities; i++)
            {
                const html_entity_t *ent = &HTMLEntities[i];
                int len = strlen(ent->ent);
                if (!strncmp(s, ent->ent, len))
                {
                    PUSHCHAR(ent->c);
                    s += len;
                    found = TRUE;
                    break;
                }
            }
            if (!found) PUSHCHAR(*s++);
        }
        else
            PUSHCHAR(*s++);
    }
    PUSHCHAR(0);

    return result;
}


char *nn_dbldecode_str(const char *str)
{
    char *res, *tmp;

    if ((tmp = nn_decode_str1(str)) == NULL)
        return NULL;

    res = nn_decode_str2(tmp);
    th_free(tmp);

    return res;
}


char *nn_dblencode_str(const char *str)
{
    char *res, *tmp;

    if ((tmp = nn_encode_str2(str)) == NULL)
        return NULL;

    res = nn_encode_str1(tmp);
    th_free(tmp);

    return res;
}


int nn_editbuf_write(nn_editbuf_t *buf, ssize_t pos, int ch)
{
    if (buf->len+1 >= buf->size) return -3;

    if (pos < 0)
        return -1;
    else if (pos >= buf->len)
        buf->data[buf->len++] = ch;
    else
        buf->data[pos] = ch;

    return 0;
}


int nn_editbuf_insert(nn_editbuf_t *buf, ssize_t pos, int ch)
{
    if (buf->len+1 >= buf->size) return -3;

    if (pos < 0)
        return -1;
    else if (pos >= buf->len)
    {
        buf->data[buf->len] = ch;
    }
    else
    {
        memmove(&(buf->data[pos+1]), &(buf->data[pos]), buf->len - pos + 1);
        buf->data[pos] = ch;
    }
    buf->len++;
    return 0;
}


int nn_editbuf_delete(nn_editbuf_t *buf, ssize_t pos)
{
    if (pos < 0)
        return -1;
    else if (pos < buf->len)
    {
        memmove(&(buf->data[pos]), &(buf->data[pos+1]), buf->len - pos);
        buf->len--;
        return 0;
    }
    else
        return -2;
}


void nn_editbuf_clear(nn_editbuf_t *buf)
{
    buf->len = 0;
    buf->pos = 0;
}


nn_editbuf_t * nn_editbuf_new(ssize_t n)
{
    nn_editbuf_t *res = th_calloc(1, sizeof(nn_editbuf_t));

    res->data = (char *) th_malloc(n);
    res->size = n;

    return res;
}


void nn_editbuf_free(nn_editbuf_t *buf)
{
    if (buf != NULL)
    {
        th_free(buf->data);
        th_free(buf);
    }
}


nn_editbuf_t * nn_editbuf_copy(nn_editbuf_t *src)
{
    nn_editbuf_t *res;

    assert(src != NULL);

    if (src == NULL) return NULL;

    if ((res = nn_editbuf_new(src->size)) == NULL)
        return NULL;

    memcpy(res->data, src->data, src->size);
    res->pos = res->len = src->len;

    return res;
}


char * nn_editbuf_get_string(nn_editbuf_t *buf, ssize_t start, ssize_t end)
{
    char *str;
    ssize_t siz;

    if (buf == NULL)
        return NULL;

    if (start < 0 || end > buf->len || start >= buf->len)
        return NULL;

    if (end < 0)
    {
        siz = buf->len - start + 1;
    }
    else if (start <= end)
    {
        siz = end - start + 1;
    }
    else
        return NULL;

    if ((str = th_malloc(siz + 1)) == NULL)
        return NULL;

    memcpy(str, buf->data + start, siz);
    str[siz] = 0;

    return str;
}


void nn_editbuf_setpos(nn_editbuf_t *buf, ssize_t pos)
{
    assert(buf != NULL);

    if (pos < 0)
        buf->pos = 0;
    else if (pos >= buf->len)
        buf->pos = buf->len;
    else
        buf->pos = pos;
}


static uint8_t nn_hash_user(const char *name)
{
/*
    int n = 0;
    const uint8_t *c = (uint8_t *)name;
    uint8_t hash = 0xff;
    
    while (*c && n < 4)
    {
        hash = (hash << 1) ^ tolower(*c);
        c++; n++;
    }
    
    return (hash & 0xff);
*/
    return tolower(name[0]);
}


static void nn_user_insert(nn_user_t **list, nn_user_t *node)
{
    node->next = *list;
    *list = node;
}


nn_user_t *nn_userhash_foreach(const nn_userhash_t *list, int (*func)(const nn_user_t *))
{
    int i;

    if (list == NULL) return NULL;

    for (i = 0; i < NN_NUM_BUCKETS; i++)
        if (list->buckets[i] != NULL)
        {
            nn_user_t *curr = list->buckets[i];
            while (curr != NULL)
            {
                if (func(curr) != 0)
                    return curr;
                curr = curr->next;
            }
        }

    return NULL;
}


nn_user_t *nn_user_find(const nn_userhash_t *list, const char *name)
{
    uint8_t hash;

    if (list == NULL) return NULL;

    hash = nn_hash_user(name);
    if (list->buckets[hash] != NULL)
    {
        nn_user_t *curr = list->buckets[hash];
        while (curr != NULL)
        {
            if (th_strcasecmp(curr->name, name) == 0)
                return curr;
            curr = curr->next;
        }
    }

    return NULL;
}


static nn_user_t *nn_user_match_do(nn_user_t *list, const char *pattern, size_t len)
{
    nn_user_t *curr = list;

    while (curr != NULL)
    {
        if (len <= strlen(curr->name) && th_strncasecmp(curr->name, pattern, len) == 0)
            return curr;
        curr = curr->next;
    }
    return NULL;
}


nn_user_t *nn_user_match(const nn_userhash_t *list, const char *pattern, const char *current, BOOL again)
{
    uint8_t hash;

    if (list == NULL || pattern == NULL) return NULL;

    hash = nn_hash_user(pattern);
    if (list->buckets[hash] != NULL)
    {
        nn_user_t *curr = list->buckets[hash];
        size_t len = strlen(pattern);

        if (current != NULL)
        {
            nn_user_t *found = NULL;
            while (curr != NULL)
            {
                if (th_strcasecmp(curr->name, current) == 0)
                {
                    if (again)
                        return curr;
                    found = curr->next;
                    break;
                }
                curr = curr->next;
            }

            if (found != NULL && (found = nn_user_match_do(found, pattern, len)) != NULL)
                return found;
        }

        if ((curr = nn_user_match_do(list->buckets[hash], pattern, len)) != NULL)
            return curr;
    }

    return NULL;
}


nn_userhash_t *nn_userhash_new(void)
{
    return th_calloc(1, sizeof(nn_userhash_t));
}


int nn_userhash_insert(nn_userhash_t *list, const char *name)
{
    uint8_t hash;
    nn_user_t *user;

    /* Check arguments */
    if (list == NULL || name == NULL)
        return -1;

    /* Check if username is already there */
    if (nn_user_find(list, name) != NULL)
        return 1;

    /* No, we'll add it */
    if ((user = th_calloc(1, sizeof(nn_user_t))) == NULL)
        return -3;

    user->name = th_strdup(name);
    if (user->name == NULL)
        return -4;

    hash = nn_hash_user(name);
    nn_user_insert(&(list->buckets[hash]), user);

    return 0;
}


int nn_userhash_delete(nn_userhash_t *list, const char *name)
{
    uint8_t hash;

    /* Check arguments */
    if (list == NULL || name == NULL)
        return -1;

    /* Check if username is already there */
    hash = nn_hash_user(name);
    if (list->buckets[hash] != NULL)
    {
        nn_user_t *curr, *prev;
        curr = list->buckets[hash];
        prev = NULL;
        while (curr != NULL)
        {
            if (th_strcasecmp(curr->name, name) == 0)
            {
                if (prev)
                    prev->next = curr->next;
                else
                    list->buckets[hash] = curr->next;

                nn_user_free(curr);

                return 0;
            }
            else
            {
                prev = curr;
                curr = curr->next;
            }
        }
    }

    return 1;
}


nn_user_t *nn_user_copy(const nn_user_t *src)
{
    nn_user_t *user;

    if (src == NULL) return NULL;

    if ((user = th_calloc(1, sizeof(nn_user_t))) == NULL)
        return NULL;

    /* Copy relevant data */
    user->name = th_strdup(src->name);
    user->lastspoke = src->lastspoke;
    user->joined = src->joined;

    return user;
}


void nn_user_free(nn_user_t *user)
{
    th_free(user->name);
    th_free(user);
}


void nn_user_free_list(nn_user_t *list)
{
    nn_user_t *next, *curr = list;

    while (curr != NULL)
    {
        next = curr->next;
        nn_user_free(curr);
        curr = next;
    }
}

void nn_userhash_free(nn_userhash_t *hash)
{
    int i;
    if (hash == NULL)
        return;

    for (i = 0; i < NN_NUM_BUCKETS; i++)
    {
        nn_user_free_list(hash->buckets[i]);
        hash->buckets[i] = NULL;
    }

    th_free(hash);
}


char *nn_username_encode(char *str)
{
    unsigned char *c = (unsigned char *) str;
    if (str == NULL) return NULL;
    for (; *c ; c++)
        if (*c == ' ') *c = 255;
    return str;
}


char *nn_username_decode(char *str)
{
    unsigned char *c = (unsigned char *) str;
    if (str == NULL) return NULL;
    for (; *c ; c++)
        if (*c == 255) *c = ' ';
    return str;
}


nn_window_t *nn_window_new(const char *id)
{
    nn_window_t *res = th_calloc(1, sizeof(nn_window_t));

    if (res == NULL) return NULL;

    res->data = th_ringbuf_new(NN_BACKBUF_LEN, th_free);
    if (res->data == NULL)
    {
        th_free(res);
        return NULL;
    }

    res->id = th_strdup(id);

    return res;
}


void nn_window_free(nn_window_t *win)
{
    if (win != NULL)
    {
        th_ringbuf_free(win->data);
        th_free(win->id);
        th_free(win);
    }
}


nn_strtuple_t *nn_strtuple_new(size_t len, char *str)
{
    nn_strtuple_t *tuple = th_calloc(1, sizeof(nn_strtuple_t));
    tuple->len = len;
    tuple->str = str;
    return tuple;
}


void nn_strtuple_free(nn_strtuple_t *tuple)
{
    th_free(tuple->str);
    th_free(tuple);
}