/*
 * Conky, a system monitor, based on torsmo
 *
 * Please see COPYING for details
 *
 * Copyright (c) 2005-2009 Brenden Matthews, Philip Kovacs, et. al.
 *	(see AUTHORS)
 * All rights reserved.
 *
 * 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 3 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/>.
 *
 */

/*
 * TODO: Add weather forecast info from weather.com
 *
 */

#include "conky.h"
#include "logging.h"
#include "weather.h"
#include "temphelper.h"
#include <time.h>
#include <ctype.h>
#ifdef MATH
#include <math.h>
#endif /* MATH */
#include <curl/curl.h>
#include <curl/types.h>
#include <curl/easy.h>
#include <libxml/parser.h>

/* Possible sky conditions */
#define NUM_CC_CODES 6
const char *CC_CODES[NUM_CC_CODES] = {
	"SKC", "CLR", "FEW", "SCT", "BKN", "OVC"
};

/* Possible weather modifiers */
#define NUM_WM_CODES 9
const char *WM_CODES[NUM_WM_CODES] = {
	"VC", "MI", "BC", "PR", "TS", "BL",
	"SH", "DR", "FZ"
};

/* Possible weather conditions */
#define NUM_WC_CODES 17
const char *WC_CODES[NUM_WC_CODES] = {
	"DZ", "RA", "GR", "GS", "SN", "SG",
	"FG", "HZ", "FU", "BR", "DU", "SA",
	"FC", "PO", "SQ", "SS", "DS",
};

typedef struct location_ {
	char *uri;
	int last_update;
	PWEATHER data;
	timed_thread *p_timed_thread;
	struct location_ *next;
} location;

static location *locations_head = 0;

location *find_location(char *uri)
{
	location *tail = locations_head;
	location *new = 0;
	while (tail) {
		if (tail->uri &&
				strcmp(tail->uri, uri) == EQUAL) {
			return tail;
		}
		tail = tail->next;
	}
	if (!tail) { // new location!!!!!!!
		new = malloc(sizeof(location));
		memset(new, 0, sizeof(location));
		new->uri = strndup(uri, text_buffer_size);
		tail = locations_head;
		while (tail && tail->next) {
			tail = tail->next;
		}
		if (!tail) {
			// omg the first one!!!!!!!
			locations_head = new;
		} else {
			tail->next = new;
		}
	}
	return new;
}

void free_weather_info(void)
{
	location *tail = locations_head;
	location *last = 0;

	while (tail) {
		if (tail->uri) free(tail->uri);
		last = tail;
		tail = tail->next;
		free(last);
	}
	locations_head = 0;
}

int rel_humidity(int dew_point, int air) {
	const float a = 17.27f;
	const float b = 237.7f;

	float diff = a*(dew_point/(b+dew_point)-air/(b+air));
#ifdef MATH
	return (int)(100.f*expf(diff));
#else
	return (int)(16.666667163372f*(6.f+diff*(6.f+diff*(3.f+diff))));
#endif /* MATH */
}

//TODO: Lets get rid of the recursion
static void parse_cc(PWEATHER *res, xmlNodePtr cc)
{

  xmlNodePtr cur = NULL;

  for (cur = cc; cur; cur = cur->next) {
    if (cur->type == XML_ELEMENT_NODE) {
      if (!xmlStrcmp(cur->name, (const xmlChar *) "lsup")) {
	strncpy(res->lastupd, (char *)cur->children->content, 31);
      } else if	(!xmlStrcmp(cur->name, (const xmlChar *) "tmp")) {
	res->temp = atoi((char *)cur->children->content);
      } else if (!xmlStrcmp(cur->name, (const xmlChar *) "t")) {
	if(res->xoap_t[0] == '\0') {
	  strncpy(res->xoap_t, (char *)cur->children->content, 31);
	}
      } else if (!xmlStrcmp(cur->name, (const xmlChar *) "r")) {
	res->bar = atoi((char *)cur->children->content);
      } else if (!xmlStrcmp(cur->name, (const xmlChar *) "s")) {
	res->wind_s = atoi((char *)cur->children->content);
      } else if (!xmlStrcmp(cur->name, (const xmlChar *) "d")) {
	if (isdigit((char)cur->children->content[0])) {
	    res->wind_d = atoi((char *)cur->children->content);
	  }
      } else if (!xmlStrcmp(cur->name, (const xmlChar *) "hmid")) {
	res->hmid = atoi((char *)cur->children->content);
      }
    }
    parse_cc(res, cur->children);
  }
  return;
}

static void parse_weather_xml(PWEATHER *res, const char *data)
{
  xmlDocPtr doc;
  xmlNodePtr cur;

  if (!(doc = xmlReadMemory(data, strlen(data), "", NULL, 0))) {
    ERR("weather: can't read xml data");
    return;
  }

  cur = xmlDocGetRootElement(doc);

  while(cur) {
    if (cur->type == XML_ELEMENT_NODE) {
      if (!xmlStrcmp(cur->name, (const xmlChar *) "weather")) {
	cur = cur->children;
	while (cur != NULL) {
	  if (cur->type == XML_ELEMENT_NODE) {
	    if (!xmlStrcmp(cur->name, (const xmlChar *) "cc")) {
	      parse_cc(res, cur->children);
	      xmlFreeDoc(doc);
	      return;
	    }
	  }
	  cur = cur->next;
	}
      }
    }
    cur = cur->next;
  }

  ERR("weather: incorrect xml data");
  xmlFreeDoc(doc);
  return ;
}

/*
 * Horrible hack to avoid using regexes
 *
 */

static inline void parse_token(PWEATHER *res, char *token) {

	int i;
	char s_tmp[64];

	switch (strlen(token)) {

		//Check all tokens 2 chars long
		case 2:

			//Check if token is a weather condition
			for (i=0; i<2; i++) {
				if (!isalpha(token[i])) break;
			}
			if (i==2) {
				for(i=0; i<NUM_WC_CODES; i++) {
					if (!strncmp(token, WC_CODES[i], 2)) {
						res->wc=i+1;
						break;
					}
				}
				return;
			}

			//Check for CB
			if (!strcmp(token, "CB")) {
				res->cc = 8;
				return;
			}

			break;

			//Check all tokens 3 chars long
		case 3:

			//Check if token is a modified weather condition
			if ((token[0] == '+') || (token[0] == '-')) {
				for (i=1; i<3; i++) {
					if (!isalpha(token[i])) break;
				}
				if (i==3) {
					for(i=0; i<NUM_WC_CODES; i++) {
						if (!strncmp(&token[1], WC_CODES[i], 2)) {
							res->wc=i+1;
							break;
						}
					}
					return;
				}
			}

			//Check for NCD or NSC
			if ((!strcmp(token, "NCD")) || (!strcmp(token, "NSC"))) {
				res->cc = 1;
				return;
			}

			//Check for TCU
			if (!strcmp(token, "TCU")) {
				res->cc = 7;
				return;
			}

			break;

			//Check all tokens 4 chars long
		case 4:

			//Check if token is a modified weather condition
			for(i=0; i<NUM_WM_CODES; i++) {
				if (!strncmp(token, WM_CODES[i], 2)) {
					for(i=0; i<NUM_WC_CODES; i++) {
						if (!strncmp(&token[2], WC_CODES[i], 2)) {
							res->wc=i+1;
							return;
						}
					}
					break;
				}
			}

			break;

			//Check all tokens 5 chars long
		case 5:

			//Check for CAVOK
			if (!strcmp(token, "CAVOK")) {
				res->cc = 1;
				return;
			}

			//Check if token is the temperature
			for (i=0; i<2; i++) {
				if (!isdigit(token[i])) break;
			}
			if ((i==2) && (token[2] == '/')) {
				for (i=3; i<5; i++) {
					if (!isdigit(token[i])) break;
				}
				if (i==5) {
					//First 2 digits gives the air temperature
					res->temp=atoi(token);

					//4th and 5th digits gives the dew point temperature
					res->dew=atoi(&token[3]);

					//Compute humidity
					res->hmid = rel_humidity(res->dew, res->temp);

					return;
				}
			}

			//Check if token is the pressure
			if ((token[0] == 'Q') || (token[0] == 'A')) {
				for (i=1; i<5; i++) {
					if (!isdigit(token[i])) break;
				}
				if (i==5) {
					if (token[0] == 'A') {
						//Convert inches of mercury to mbar
						res->bar = (int)(atoi(&token[1])*0.338637526f);
						return;
					}

					//Last 4 digits is pressure im mbar
					res->bar = atoi(&token[1]);
					return;
				}
			}

			//Check if token is a modified weather condition
			if ((token[0] == '+') || (token[0] == '-')) {
				for(i=0; i<NUM_WM_CODES; i++) {
					if (!strncmp(&token[1], WM_CODES[i], 2)) {
						for(i=0; i<NUM_WC_CODES; i++) {
							if (!strncmp(&token[3], WC_CODES[i], 2)) {
								res->wc=i+1;
								return;
							}
						}
						break;
					}
				}
			}
			break;

			//Check all tokens 6 chars long
		case 6:

			//Check if token is the cloud cover
			for (i=0; i<3; i++) {
				if (!isalpha(token[i])) break;
			}
			if (i==3) {
				for (i=3; i<6; i++) {
					if (!isdigit(token[i])) break;
				}
				if (i==6) {
					//Check if first 3 digits gives the cloud cover condition
					for(i=0; i<NUM_CC_CODES; i++) {
						if (!strncmp(token, CC_CODES[i], 3)) {
							res->cc=i+1;
							break;
						}
					}
					return;
				}
			}

			//Check if token is positive temp and negative dew
			for (i=0; i<2; i++) {
				if (!isdigit(token[i])) break;
			}
			if ((i==2) && (token[2] == '/')  && (token[3] == 'M')) {
				for (i=4; i<6; i++) {
					if (!isdigit(token[i])) break;
				}
				if (i==6) {
					//1st and 2nd digits gives the temperature
					res->temp = atoi(token);

					//5th and 6th digits gives the dew point temperature
					res->dew = -atoi(&token[4]);

					//Compute humidity
					res->hmid = rel_humidity(res->dew, res->temp);

					return;
				}
			}

			break;

			//Check all tokens 7 chars long
		case 7:

			//Check if token is the observation time
			for (i=0; i<6; i++) {
				if (!isdigit(token[i])) break;
			}
			if ((i==6) && (token[6] == 'Z')) return;

			//Check if token is the wind speed/direction in knots
			for (i=0; i<5; i++) {
				if (!isdigit(token[i])) break;
			}
			if ((i==5) && (token[5] == 'K') &&  (token[6] == 'T')) {

				//First 3 digits are wind direction
				strncpy(s_tmp, token, 3);
				s_tmp[3]='\0';
				res->wind_d=atoi(s_tmp);

				//4th and 5th digit are wind speed in knots (convert to km/hr)
				res->wind_s = (int)(atoi(&token[3])*1.852);

				return;
			}

			//Check if token is negative temperature
			if ((token[0] == 'M') && (token[4] == 'M')) {
				for (i=1; i<3; i++) {
					if (!isdigit(token[i])) break;
				}
				if ((i==3) && (token[3] == '/')) {
					for (i=5; i<7; i++) {
						if (!isdigit(token[i])) break;
					}
					if (i==7) {
						//2nd and 3rd digits gives the temperature
						res->temp = -atoi(&token[1]);

						//6th and 7th digits gives the dew point temperature
						res->dew = -atoi(&token[5]);

						//Compute humidity
						res->hmid = rel_humidity(res->dew, res->temp);

						return;
					}
				}
			}

			//Check if token is wind variability
			for (i=0; i<3; i++) {
				if (!isdigit(token[i])) break;
			}
			if ((i==3) && (token[3] == 'V')) {
				for (i=4; i<7; i++) {
					if (!isdigit(token[i])) break;
				}
				if (i==7) return;
			}

			break;

			//Check all tokens 8 chars long
		case 8:

			//Check if token is the wind speed/direction in m/s
			for (i=0; i<5; i++) {
				if (!isdigit(token[i])) break;
			}
			if ((i==5)&&(token[5] == 'M')&&(token[6] == 'P')&&(token[7] == 'S')) {

				//First 3 digits are wind direction
				strncpy(s_tmp, token, 3);
				s_tmp[3]='\0';
				res->wind_d=atoi(s_tmp);

				//4th and 5th digit are wind speed in m/s (convert to km/hr)
				res->wind_s = (int)(atoi(&token[3])*3.6);

				return;
			}

		default:

			//printf("token : %s\n", token);
			break;
	}
}

static void parse_weather(PWEATHER *res, const char *data)
{
        //Reset results
	memset(res, 0, sizeof(PWEATHER));

	//Check if it is an xml file
	if ( strncmp(data, "<?xml ", 6) == 0 ) {
	  parse_weather_xml(res, data);
	} else {
	  //We assume its a text file
	  char s_tmp[256];
	  const char delim[] = " ";

	  //Divide time stamp and metar data
	  if (sscanf(data, "%[^'\n']\n%[^'\n']", res->lastupd, s_tmp) == 2) {

	    //Process all tokens
	    char *p_tok = NULL;
	    char *p_save = NULL;

	    if ((strtok_r(s_tmp, delim, &p_save)) != NULL) {

	      //Jump first token, must be icao
	      p_tok = strtok_r(NULL, delim, &p_save);

	      do {

		parse_token(res, p_tok);
		p_tok = strtok_r(NULL, delim, &p_save);

	      } while (p_tok != NULL);
	    }
	    return;
	  }
	  else {
	    return;
	  }
	}
}

void fetch_weather_info(location *curloc)
{
	CURL *curl = NULL;
	CURLcode res;

	// curl temps
	struct MemoryStruct chunk;

	chunk.memory = NULL;
	chunk.size = 0;

	curl = curl_easy_init();
	if (curl) {
		curl_easy_setopt(curl, CURLOPT_URL, curloc->uri);
		curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1);
		curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
		curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *) &chunk);
		curl_easy_setopt(curl, CURLOPT_USERAGENT, "conky-weather/1.0");

		res = curl_easy_perform(curl);
		if (chunk.size) {
			timed_thread_lock(curloc->p_timed_thread);
			parse_weather(&curloc->data, chunk.memory);
			timed_thread_unlock(curloc->p_timed_thread);
			free(chunk.memory);
		} else {
			ERR("weather: no data from server");
		}

		curl_easy_cleanup(curl);
	}

	return;
}

void *weather_thread(void *) __attribute__((noreturn));

void init_thread(location *curloc, int interval)
{
	curloc->p_timed_thread =
		timed_thread_create(&weather_thread,
				(void *)curloc, interval * 1000000);
	if (!curloc->p_timed_thread) {
		ERR("weather: error creating timed thread");
	}
	timed_thread_register(curloc->p_timed_thread,
			&curloc->p_timed_thread);
	if (timed_thread_run(curloc->p_timed_thread)) {
		ERR("weather: error running timed thread");
	}
}


void process_weather_info(char *p, int p_max_size, char *uri, char *data_type, int interval)
{
	static const char *wc[] = {
		"", "drizzle", "rain", "hail", "soft hail",
		"snow", "snow grains", "fog", "haze", "smoke",
		"mist", "dust", "sand", "funnel cloud tornado",
		"dust/sand", "squall", "sand storm", "dust storm"
	};

	location *curloc = find_location(uri);
	if (!curloc->p_timed_thread) init_thread(curloc, interval);

	timed_thread_lock(curloc->p_timed_thread);
	if (strcmp(data_type, "last_update") == EQUAL) {
		strncpy(p, curloc->data.lastupd, p_max_size);
	} else if (strcmp(data_type, "temperature") == EQUAL) {
		temp_print(p, p_max_size, curloc->data.temp, TEMP_CELSIUS);
	} else if (strcmp(data_type, "cloud_cover") == EQUAL) {
	        if (curloc->data.xoap_t[0] != '\0') {
			strncpy(p, curloc->data.xoap_t, p_max_size);
		} else if (curloc->data.cc == 0) {
			strncpy(p, "", p_max_size);
		} else if (curloc->data.cc < 3) {
			strncpy(p, "clear", p_max_size);
		} else if (curloc->data.cc < 5) {
			strncpy(p, "partly cloudy", p_max_size);
		} else if (curloc->data.cc == 5) {
			strncpy(p, "cloudy", p_max_size);
		} else if (curloc->data.cc == 6) {
			strncpy(p, "overcast", p_max_size);
		} else if (curloc->data.cc == 7) {
			strncpy(p, "towering cumulus", p_max_size);
		} else  {
			strncpy(p, "cumulonimbus", p_max_size);
		}
	} else if (strcmp(data_type, "pressure") == EQUAL) {
		snprintf(p, p_max_size, "%d", curloc->data.bar);
	} else if (strcmp(data_type, "wind_speed") == EQUAL) {
		snprintf(p, p_max_size, "%d", curloc->data.wind_s);
	} else if (strcmp(data_type, "wind_dir") == EQUAL) {
		if ((curloc->data.wind_d >= 349) || (curloc->data.wind_d < 12)) {
			strncpy(p, "N", p_max_size);
		} else if (curloc->data.wind_d < 33) {
			strncpy(p, "NNE", p_max_size);
		} else if (curloc->data.wind_d < 57) {
			strncpy(p, "NE", p_max_size);
		} else if (curloc->data.wind_d < 79) {
			strncpy(p, "ENE", p_max_size);
		} else if (curloc->data.wind_d < 102) {
			strncpy(p, "E", p_max_size);
		} else if (curloc->data.wind_d < 124) {
			strncpy(p, "ESE", p_max_size);
		} else if (curloc->data.wind_d < 147) {
			strncpy(p, "SE", p_max_size);
		} else if (curloc->data.wind_d < 169) {
			strncpy(p, "SSE", p_max_size);
		} else if (curloc->data.wind_d < 192) {
			strncpy(p, "S", p_max_size);
		} else if (curloc->data.wind_d < 214) {
			strncpy(p, "SSW", p_max_size);
		} else if (curloc->data.wind_d < 237) {
			strncpy(p, "SW", p_max_size);
		} else if (curloc->data.wind_d < 259) {
			strncpy(p, "WSW", p_max_size);
		} else if (curloc->data.wind_d < 282) {
			strncpy(p, "W", p_max_size);
		} else if (curloc->data.wind_d < 304) {
			strncpy(p, "WNW", p_max_size);
		} else if (curloc->data.wind_d < 327) {
			strncpy(p, "NW", p_max_size);
		} else if (curloc->data.wind_d < 349) {
			strncpy(p, "NNW", p_max_size);
		};
	} else if (strcmp(data_type, "wind_dir_DEG") == EQUAL) {
		snprintf(p, p_max_size, "%d", curloc->data.wind_d);

	} else if (strcmp(data_type, "humidity") == EQUAL) {
		snprintf(p, p_max_size, "%d", curloc->data.hmid);
	} else if (strcmp(data_type, "weather") == EQUAL) {
		strncpy(p, wc[curloc->data.wc], p_max_size);
	}

	timed_thread_unlock(curloc->p_timed_thread);
}

void *weather_thread(void *arg)
{
	location *curloc = (location*)arg;

	while (1) {
		fetch_weather_info(curloc);
		if (timed_thread_test(curloc->p_timed_thread, 0)) {
			timed_thread_exit(curloc->p_timed_thread);
		}
	}
	/* never reached */
}