#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <curl/curl.h>
//#include <curl/types.h>
#include <curl/easy.h>


#define USERAGENT "libcurl-agent/1.0"

struct MemoryStruct 
{
   char   *memory;
   size_t  size;
   int tagMatch;
   char tag[100];
   char ignoreTag[100];
} data;


int getTag(const char* filename, char* tag, int len)
{
   FILE* f;
   *tag = 0;

   if (!access(filename, F_OK))
   {
      if ((f = fopen(filename, "r")))
      {
         char* line = 0;
         size_t size = 0;

         if (getline(&line, &size, f) > 0)
         {
            sprintf(tag, "%.*s", len, line);
            tag[strlen(tag)-1] = 0;
            printf("'%s'\n", tag);
         }

         fclose(f);
      }
   }

   return 0;
}

//***************************************************************************
// 
//***************************************************************************

static size_t WriteMemoryCallback(void* ptr, size_t size, size_t nmemb, void* data)
{
   size_t realsize = size * nmemb;
   struct MemoryStruct* mem = (struct MemoryStruct*)data;
   
   if (mem->memory)
      mem->memory = (char*)realloc(mem->memory, mem->size + realsize + 1);
   else
      mem->memory = (char*)malloc(mem->size + realsize + 1);
   
   if (mem->memory)
   {
      memcpy (&(mem->memory[mem->size]), ptr, realsize);
      mem->size += realsize;
      mem->memory[mem->size] = 0;
   }

   return realsize;
}

static size_t WriteHeaderCallback(void* ptr, size_t size, size_t nmemb, void* data)
{
   size_t realsize = size * nmemb;
   struct MemoryStruct* mem = (struct MemoryStruct*)data;
   char* p;

   if (ptr && (p = strcasestr((char*)ptr, "ETag: ")))
   {
      // etag found ...
      
      sprintf(mem->tag, "%s", p+7);

      if ((p = strchr(mem->tag, '"')))
          *p = 0;

      mem->tagMatch = (strcmp(mem->tag, mem->ignoreTag) == 0);

      // ignore download if tag matches ...

      if (mem->tagMatch)
         return 0;
   }

   return realsize;
}

//***************************************************************************
// 
//***************************************************************************

int DownloadData(const char* url, int& size, const char* etag)
{
   CURL* curl_handle;
   long code;
   long res;

   // Initialize 'data' struct
   
   if (data.memory)
      free(data.memory);
   
   data.memory = 0;
   data.size = 0;
   data.tagMatch = 1;
   *data.ignoreTag = 0;

   strcpy(data.ignoreTag, etag);

   if (curl_global_init(CURL_GLOBAL_ALL) != 0)
   {
      printf("TVM2VDR: Error, something went wrong with curl_global_init()\n");
      
      return -1;
   }
   
   curl_handle = curl_easy_init();
   
   if (!curl_handle)
   {
      printf("TVM2VDR: Error, unable to get handle from curl_easy_init()\n");
      
      return -1;
   }
  
   curl_easy_setopt(curl_handle, CURLOPT_URL, url);                            // Specify URL to get   
   curl_easy_setopt(curl_handle, CURLOPT_FOLLOWLOCATION, 0);                   // don't follow redirects

   curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);  // Send all data to this function
   curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void*)&data);             // Pass our 'data' struct to the callback function

   curl_easy_setopt(curl_handle, CURLOPT_HEADERFUNCTION, WriteHeaderCallback); // Send all data to this function
   curl_easy_setopt(curl_handle, CURLOPT_WRITEHEADER, (void*)&data);           // Pass our 'data' struct to the callback function

   curl_easy_setopt(curl_handle, CURLOPT_MAXFILESIZE, 1024*1024);              // Set maximum file size to get (bytes)
   curl_easy_setopt(curl_handle, CURLOPT_NOPROGRESS, 1);                       // No progress meter
   curl_easy_setopt(curl_handle, CURLOPT_NOSIGNAL, 1);                         // No signaling
   curl_easy_setopt(curl_handle, CURLOPT_TIMEOUT, 30);                         // Set timeout to 30 seconds
   curl_easy_setopt(curl_handle, CURLOPT_USERAGENT, USERAGENT);                // Some servers don't like requests that are made without a user-agent field

   if ((res = curl_easy_perform(curl_handle)) != 0)
   {
      curl_easy_cleanup(curl_handle);  // Cleanup curl stuff
      
      if (data.memory)
      {
         free(data.memory);
         data.memory = 0;
         data.size = 0;
      }

      if (res == CURLE_WRITE_ERROR && data.tagMatch)
         return -2;

      printf("TVM2VDR: Error, download of '%s' failed, result was %ld\n", url, res);

      return -1;
   }

   curl_easy_getinfo(curl_handle, CURLINFO_HTTP_CODE, &code); 

   if (code == 404)
   {
      if (data.memory)
         free(data.memory);
      
      data.memory = 0;
      data.size = 0;
   }

   curl_easy_cleanup(curl_handle);     // Cleanup curl stuff
   size = data.size;

   return 0;
}

//***************************************************************************
// Main
//***************************************************************************

int main(int argc, char** argv)
{
   int size = 0;
   int res;

   if (argc < 2)
   {
      printf("Usage: %s <etag>\n", argv[0]);
      return 1;
   }

   // res = DownloadData("http://img.tvmovie.de/imageTransfer/F1_2931803.jpg", size);
   res = DownloadData("http://wwwa.tvmovie.de/static/tvghost/html/onlinedata/xml-gz5/20120516_190.xml.tvm", 
                      size, argv[1]);

   if (!res)
   {
      FILE* fout;
      printf("Transfered (%d) bytes\n", size);
      printf("-> (%s) [%.10s...]\n", data.tag, data.memory);

      if ((fout = fopen("tagfile", "w")))
      {
         fwrite(data.tag, strlen(data.tag), 1, fout);
         fwrite("\n", 1, 1, fout);
         fclose(fout);
      }
      char tag[100];
      getTag("tagfile", tag, 100);
   }
   else if (res == -2)
      printf("Skipping download due to non update\n");

   return 0;   
}