/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2015 Olaf Wintermann. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ucx/string.h>
#include <ucx/buffer.h>
#include <ucx/utils.h>
#include <libxml/tree.h>
#include <curl/curl.h>

#include <openssl/sha.h>
#include <openssl/hmac.h>
#include <openssl/evp.h>
#include <openssl/bio.h>
#include <openssl/buffer.h>
#include <openssl/rand.h>

#include "utils.h"
#include "crypto.h"
#include "webdav.h"

#define MACRO1337 1337L

/* -------------------- This is a testing file. -------------------------- */
/*
time_t util_parse_creationdate(char *str) {
    // example: 2012-11-29T21:35:35Z
    if(!str) {
        return 0;
    }
    // TODO
    return 0;
}
*/
time_t util_parse_lastmodified(char *str) {
    // example: Thu, 29 Nov 2012 21:35:35 GMT
    if(!str) {
        return 0;
    } else {
        return curl_getdate(str, NULL);
    }
}

int util_getboolean(char *v) {
    if(v[0] == 'T' || v[0] == 't') {
        return 1;
    }
    return 0;
}

int util_strtoint(char *str, int64_t *value) {
    char *end;
    int64_t val = strtoll(str, &end, 0);
    if(strlen(end) == 0) {
        *value = val;
        return 1;
    } else {
        return 0;
    }
}

char* util_url_path(char *url) { 
    char *path = NULL;
    size_t len = strlen(url);
    int slashcount = 0;
    int slmax;
    if(len > 7 && !strncasecmp(url, "http://", 7)) {
        slmax = 3;
    } else if(len > 8 && !strncasecmp(url, "https://", 8)) {
        slmax = 3;
    } else {
        slmax = 1;
    }
    char c;
    for(int i=0;i<len;i++) {
        c = url[i];
        if(c == '/') {
            slashcount++;
            if(slashcount == slmax) {
                path = url + i;
                break;
            }
        }
    } 
    return path;
}

char* util_url_decode(DavSession *sn, char *url) {
    char *unesc = curl_easy_unescape(sn->handle, url, strlen(url), NULL);
    char *ret = strdup(unesc);
    curl_free(unesc);
    return ret;
}

char* util_resource_name(char *url) {
    int si = 0;
    int osi = 0;
    int i = 0;
    int p = 0;
    char c;
    while((c = url[i]) != 0) {
        if(c == '/') {
            osi = si;
            si = i;
            p = 1;
        }
        i++;
    }
    
    char *name = url + si + p;
    if(name[0] == 0) {
        name = url + osi + p;
        if(name[0] == 0) {
            return url;
        }
    }
    
    return name;
}

int util_mkdir(char *path, mode_t mode) {
#ifdef _WIN32
    return mkdir(path);
#else
    return mkdir(path, mode);
#endif
}

char* util_concat_path(char *url_base, char *p) {
    sstr_t base = sstr(url_base);
    sstr_t path;
    if(p) {
        path = sstr(p);
    } else {
        path = sstrn("", 0);
    }
    
    int add_separator = 0;
    if(base.ptr[base.length-1] == '/') {
        if(path.ptr[0] == '/') {
            base.length--;
        }
    } else {
        if(path.length == 0 || path.ptr[0] != '/') {
            add_separator = 1;
        }
    }
    
    sstr_t url;
    if(add_separator) {
        url = sstrcat(3, base, sstr("/"), path);
    } else {
        url = sstrcat(2, base, path);
    }
    
    return url.ptr;
}

void util_set_url(DavSession *sn, char *href) {
    sstr_t base = sstr(sn->base_url);
    sstr_t href_str = sstr(href);
    
    char *base_path = util_url_path(sn->base_url);
    base.length -= strlen(base_path);
    
    sstr_t url = sstrcat(2, base, href_str);
    
    curl_easy_setopt(sn->handle, CURLOPT_URL, url.ptr);
    free(url.ptr);
}

char* util_path_to_url(DavSession *sn, char *path) {
    char *space = malloc(256);
    UcxBuffer *url = ucx_buffer_new(space, 256, UCX_BUFFER_AUTOEXTEND);
    
    // add base url
    ucx_buffer_write(sn->base_url, 1, strlen(sn->base_url), url);
    // remove trailing slash
    ucx_buffer_seek(url, -1, SEEK_CUR);
    
    sstr_t p = sstr(path);
    ssize_t ntk = 0;
    sstr_t *tks = sstrsplit(p, S("/"), &ntk);
    
    for(int i=0;i<ntk;i++) {
        sstr_t node = tks[i];
        if(node.length > 0) {
            char *esc = curl_easy_escape(sn->handle, node.ptr, node.length);
            ucx_buffer_putc(url, '/');
            ucx_buffer_write(esc, 1, strlen(esc), url);
            curl_free(esc);
        }
        free(node.ptr);
    }
    free(tks);
    if(path[p.length-1] == '/') {
        ucx_buffer_putc(url, '/');
    }
    ucx_buffer_putc(url, 0);
    
    space = url->space;
    ucx_buffer_free(url);
    
    return space;
}

char* util_parent_path(char *path) {
    char *name = util_resource_name(path);
    size_t namelen = strlen(name);
    size_t pathlen = strlen(path);
    size_t parentlen = pathlen - namelen;
    char *parent = malloc(parentlen + 1);
    memcpy(parent, path, parentlen);
    parent[parentlen] = '\0';
    return parent;
}


char* util_xml_get_text(xmlNode *elm) {
    xmlNode *node = elm->children;
    while(node) {
        if(node->type == XML_TEXT_NODE) {
            return (char*)node->content;
        }
        node = node->next;
    }
    return NULL;
}


char* util_base64decode(char *in) {
    int len = 0;
    return util_base64decode_len(in, &len);
}

char* util_base64decode_len(char* in, int *outlen) {
    size_t len = strlen(in);
    char *out = calloc(1, len);
    
    BIO* b = BIO_new_mem_buf(in, len);
    BIO *d = BIO_new(BIO_f_base64());
    BIO_set_flags(d, BIO_FLAGS_BASE64_NO_NL);
    b = BIO_push(d, b);

    *outlen = BIO_read(b, out, len);
    BIO_free_all(b);
    
    return out;
}

char* util_base64encode(char *in, size_t len) { 
    BIO *b;
    BIO *e;
    BUF_MEM *mem;

    e = BIO_new(BIO_f_base64());
    b = BIO_new(BIO_s_mem());
    
    e = BIO_push(e, b);
    BIO_write(e, in, len);
    BIO_flush(e);
    
    BIO_get_mem_ptr(e, &mem);
    char *out = malloc(mem->length);
    memcpy(out, mem->data, mem->length -1);
    out[mem->length - 1] = '\0';

    BIO_free_all(e);

    return out;
}

char* util_encrypt_str(DavSession *sn, char *str, char *key) {
    DavKey *k = dav_context_get_key(sn->context, key);
    if(!k) {
        // TODO: session error
        return NULL;
    }
    
    char *enc_str = aes_encrypt(str, k);
    char *ret_str = dav_session_strdup(sn, enc_str);
    free(enc_str);
    return ret_str;
}

/* commented out for testing reasons */
/*
char* util_decrypt_str(DavSession *sn, char *str, char *key) {
    DavKey *k = dav_context_get_key(sn->context, key);
    if(!k) {
        // TODO: session error
        return NULL;
    }
    
    char *dec_str = aes_decrypt(str, k);
    char *ret_str = dav_session_strdup(sn, dec_str);
    free(dec_str);
    return ret_str;
}
*/
char* util_random_str() {
    unsigned char *str = malloc(25);
    str[24] = '\0';
    
    sstr_t t = S(
            "01234567890"
            "abcdefghijklmnopqrstuvwxyz"
            "ABCDEFGHIJKLMNOPQRSTUVWXYZ");
    const unsigned char *table = (const unsigned char*)t.ptr;
    
    RAND_pseudo_bytes(str, 24);
    for(int i=0;i<24;i++) {
        int c = str[i] % t.length;
        str[i] = table[c];
    }
    
    return (char*)str;
}

/*
 * gets a substring from 0 to the appearance of the token
 * tokens are separated by space
 * sets sub to the substring and returns the remaining string
 */
sstr_t util_getsubstr_until_token(sstr_t str, sstr_t token, sstr_t *sub) {  
    int i;
    int token_start = -1;
    int token_end = -1;
    for(i=0;i<=str.length;i++) {
        int c;
        if(i == str.length) {
            c = ' ';
        } else {
            c = str.ptr[i];
        }
        if(c < 33) {
            if(token_start != -1) {
                token_end = i;
                size_t len = token_end - token_start;
                sstr_t tk = sstrsubsl(str, token_start, len);
                //printf("token: {%.*s}\n", token.length, token.ptr);
                if(!sstrcmp(tk, token)) {
                    *sub = sstrtrim(sstrsubsl(str, 0, token_start));
                    break;
                }
                token_start = -1;
                token_end = -1;
            }
        } else {
            if(token_start == -1) {
                token_start = i;
            }
        }
    }
    
    if(i < str.length) {
        return sstrtrim(sstrsubs(str, i));
    } else {
        str.ptr = NULL;
        str.length = 0;
        return str;
    }
}