/*
  * 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;
     }
 }