zynk/cmd_forecast.h

#ifndef CMD_FORECAST_H
#define CMD_FORECAST_H

#include "zynk.h"

/*
 * parse_forecast_day - Parse a single day object from the wttr.in JSON.
 *
 * Extracts date, avg temperature, and weather condition from one day
 * object within the "weather" array. Used by both fetch_forecast() and
 * fetch_forecast_full().
 *
 * Parameters:
 *   p         - Pointer to the start of the day JSON object.
 *   obj_end   - Pointer to one past the end of the day object.
 *   date_out  - Buffer to receive the parsed date string (YYYY-MM-DD).
 *   temp_out  - Buffer to receive the average temperature.
 *   cond_out  - Buffer to receive the weather condition string.
 *
 * Returns: 1 on success, 0 on failure.
 */
static int parse_forecast_day(const char *p, const char *obj_end,
    char *date_out, size_t date_sz,
    char *temp_out, size_t temp_sz,
    char *cond_out, size_t cond_sz) {
  date_out[0] = temp_out[0] = cond_out[0] = 0;
  const char *db = strstr(p, "\"date\": \"");
  if (db && db < obj_end) { db += 9; const char *dq = strchr(db, '"'); if (dq && dq < obj_end) { size_t l = dq - db; if (l >= date_sz) l = date_sz - 1; memcpy(date_out, db, l); date_out[l] = 0; } }
  const char *tb = strstr(p, "\"avgtempC\": \"");
  if (tb && tb < obj_end) { tb += 13; const char *tq = strchr(tb, '"'); if (tq && tq < obj_end) { size_t l = tq - tb; if (l >= temp_sz) l = temp_sz - 1; memcpy(temp_out, tb, l); temp_out[l] = 0; } }
  const char *hb = strstr(p, "\"hourly\"");
  if (hb && hb < obj_end) {
    hb = strchr(hb, '[');
    if (hb && hb < obj_end) {
      hb++;
      const char *vb = strstr(hb, "\"value\": \"");
      if (vb && vb < obj_end) { vb += 9; const char *vq = strchr(vb, '"'); if (vq && vb < obj_end) { size_t l = vq - vb; if (l >= cond_sz) l = cond_sz - 1; memcpy(cond_out, vb, l); cond_out[l] = 0; while (l > 0 && cond_out[l-1] == ' ') cond_out[--l] = 0; } }
    }
  }
  return (date_out[0] != 0) ? 1 : 0;
}

/*
 * find_day_obj - Find the i-th day object in the weather JSON array.
 *
 * Scans the JSON string for the i-th '{' ... '}' block at the top level
 * of the "weather" array. Sets obj_end to one past the closing '}'.
 *
 * Parameters:
 *   p        - Pointer into the JSON string (start of the weather array).
 *   idx      - Zero-based index of the day object to find (0, 1, or 2).
 *   obj_end  - Output pointer set to one past the closing '}' of the
 *              matched day object.
 *
 * Returns: Pointer to the opening '{' of the matched day object, or NULL
 *          if fewer than idx+1 day objects exist.
 */
static const char *find_day_obj(const char *p, int idx, const char **obj_end) {
  int count = 0;
  while (*p) {
    if (*p == '{') {
      if (count == idx) {
        *obj_end = p + 1;
        int depth = 1;
        while (**obj_end && depth > 0) { if (**obj_end == '{') depth++; else if (**obj_end == '}') depth--; (*obj_end)++; }
        return p;
      }
      count++;
    }
    p++;
  }
  return NULL;
}

/*
 * to_24h - Convert a 12-hour AM/PM time string to 24-hour format.
 *
 * Parses a time string in "HH:MM AM" or "HH:MM PM" format (as returned
 * by wttr.in's astronomy fields) and overwrites the buffer with the
 * equivalent 24-hour "HH:MM" string. Handles midnight (12 AM -> 00)
 * and noon (12 PM -> 12) correctly. If the string is too short or
 * does not end with a recognized AM/PM suffix, the buffer is left
 * unchanged.
 *
 * Parameters:
 *   buf - Buffer containing the null-terminated 12-hour time string.
 *         Modified in place on success.
 *   sz  - Size of the buffer.
 */
static void to_24h(char *buf, size_t sz) {
  size_t len = strlen(buf);
  if (len < 5) return;
  char mm[4];
  memcpy(mm, buf + 3, 3);
  const char *ampm = buf + len - 2;
  if ((ampm[0] == 'A' || ampm[0] == 'a') && (ampm[1] == 'M' || ampm[1] == 'm')) {
    int h = (buf[0] - '0') * 10 + (buf[1] - '0');
    if (h == 12) h = 0;
    snprintf(buf, sz, "%02d:%s", h, mm);
  } else if ((ampm[0] == 'P' || ampm[0] == 'p') && (ampm[1] == 'M' || ampm[1] == 'm')) {
    int h = (buf[0] - '0') * 10 + (buf[1] - '0');
    if (h != 12) h += 12;
    snprintf(buf, sz, "%02d:%s", h, mm);
  }
}

/*
 * extract_astronomy - Extract sunrise/sunset/moonrise/moonset from a day object.
 *
 * Parameters:
 *   p, obj_end       - The day object boundaries.
 *   sunrise, sunset  - Buffers for sunrise/sunset strings.
 *   moonrise, moonset - Buffers for moonrise/moonset strings.
 */
static void extract_astronomy(const char *p, const char *obj_end,
    char *sunrise, size_t sr_sz,
    char *sunset, size_t ss_sz,
    char *moonrise, size_t mr_sz,
    char *moonset, size_t ms_sz) {
  sunrise[0] = sunset[0] = moonrise[0] = moonset[0] = 0;
  const char *ab = strstr(p, "\"astronomy\"");
  if (!ab || ab >= obj_end) return;
  ab = strchr(ab, '[');
  if (!ab || ab >= obj_end) return;
  ab++;
  const char *ae = ab;
  int depth = 1;
  while (*ae && depth > 0) { if (*ae == '[') depth++; else if (*ae == ']') depth--; ae++; }
  const char *fields[][2] = {
    { "\"sunrise\": \"",  NULL }, { "\"sunset\": \"",  NULL },
    { "\"moonrise\": \"", NULL }, { "\"moonset\": \"",  NULL },
  };
  size_t sizes[] = { sr_sz, ss_sz, mr_sz, ms_sz };
  char *dsts[] = { sunrise, sunset, moonrise, moonset };
  for (int f = 0; f < 4; f++) {
    const char *fb = strstr(ab, fields[f][0]);
    if (fb && fb < ae) {
      fb += strlen(fields[f][0]);
      const char *fq = strchr(fb, '"');
      if (fq && fq < ae) {
        size_t l = fq - fb;
        if (l >= sizes[f]) l = sizes[f] - 1;
        memcpy(dsts[f], fb, l);
        dsts[f][l] = 0;
      }
    }
  }
}

/*
 * fetch_forecast - Fetch and parse a 3-day weather forecast from wttr.in.
 *
 * Fetches the JSON forecast (format=j1) from wttr.in for the given city,
 * then manually parses the "weather" array to extract date, average
 * temperature, and weather condition for up to 3 days. Dates are formatted
 * as "Mon DD Mon" (e.g. "Mon 19 Jul"). Returns a single-line summary
 * string like "Forecast for Berlin: Mon 19 Jul: 22°C Partly cloudy / ...".
 *
 * Parameters:
 *   city_url      - URL-encoded city name for the API request.
 *   city_display  - Human-readable city name for the response.
 *
 * Returns: A newly allocated forecast string, or NULL/ error message on
 *          failure. Caller must free() the result.
 */
char *fetch_forecast(const char *city_url, const char *city_display) {
  char url[512];
  snprintf(url, sizeof url, "https://wttr.in/%s?format=j1", city_url);
  char *json = fetch_url(url);
  if (!json) return NULL;
  char *p = strstr(json, "\"weather\"");
  if (!p) {
    char *err = NULL;
    size_t jlen = strlen(json);
    if (jlen > 400) jlen = 400;
    if (asprintf(&err, "Forecast parse error (response: %.*s)", (int)jlen, json) < 0) err = NULL;
    free(json);
    return err;
  }
  p = strchr(p, '[');
  if (!p) { free(json); return NULL; }
  p++;
  char line[3][256], fmt_date[3][32];
  int ndays = 0;
  for (int i = 0; i < 3; i++) {
    const char *obj_end = NULL;
    const char *day = find_day_obj(p, 0, &obj_end);
    if (!day) break;
    char date[16]="", temp[8]="", cond[64]="";
    parse_forecast_day(day, obj_end, date, sizeof date, temp, sizeof temp, cond, sizeof cond);
    struct tm tm = {0};
    if (strptime(date, "%Y-%m-%d", &tm)) { mktime(&tm); strftime(fmt_date[ndays], sizeof fmt_date[ndays], "%a %d %b", &tm); }
    else snprintf(fmt_date[ndays], sizeof fmt_date[ndays], "%s", date);
    snprintf(line[ndays], sizeof line[ndays], "%s: %s\u00b0C %s", fmt_date[ndays], temp, cond);
    ndays++;
    p = (char*)obj_end;
  }
  free(json);
  if (!ndays) return NULL;
  char *out = NULL;
  if (ndays == 1) { if (asprintf(&out, "Forecast for %s: %s", city_display, line[0]) < 0) out = NULL; }
  else if (ndays == 2) { if (asprintf(&out, "Forecast for %s: %s / %s", city_display, line[0], line[1]) < 0) out = NULL; }
  else { if (asprintf(&out, "Forecast for %s: %s / %s / %s", city_display, line[0], line[1], line[2]) < 0) out = NULL; }
  if (out) collapse_spaces(out);
  return out;
}

/*
 * fetch_forecast_full - Fetch a detailed 3-day forecast from wttr.in.
 *
 * Like fetch_forecast(), but returns per-day detail lines including the
 * weather description, sunrise/sunset, and moonrise/moonset times.
 * Each day is returned as a separate line in a single string, separated
 * by newlines. Caller must free() the result.
 *
 * Parameters:
 *   city_url      - URL-encoded city name for the API request.
 *   city_display  - Human-readable city name for the response.
 *
 * Returns: A newly allocated multi-line forecast string, or NULL/error.
 */
char *fetch_forecast_full(const char *city_url, const char *city_display) {
  (void)city_display;
  char url[512];
  snprintf(url, sizeof url, "https://wttr.in/%s?format=j1", city_url);
  char *json = fetch_url(url);
  if (!json) return NULL;
  char *p = strstr(json, "\"weather\"");
  if (!p) {
    char *err = NULL;
    size_t jlen = strlen(json);
    if (jlen > 400) jlen = 400;
    if (asprintf(&err, "Forecast parse error (response: %.*s)", (int)jlen, json) < 0) err = NULL;
    free(json);
    return err;
  }
  p = strchr(p, '[');
  if (!p) { free(json); return NULL; }
  p++;
  char *out = NULL;
  size_t out_cap = 0;
  size_t out_len = 0;
  for (int i = 0; i < 3; i++) {
    const char *obj_end = NULL;
    const char *day = find_day_obj(p, 0, &obj_end);
    if (!day) break;
    char date[16]="", temp[8]="", cond[64]="";
    parse_forecast_day(day, obj_end, date, sizeof date, temp, sizeof temp, cond, sizeof cond);
    char desc[128]="";
    char *hb = strstr((char*)day, "\"hourly\"");
    if (hb && hb < obj_end) {
      hb = strchr(hb, '[');
      if (hb && hb < obj_end) {
        hb++;
        char *db = strstr(hb, "\"weatherDesc\"");
        if (db && db < obj_end) {
          db = strchr(db, '[');
          if (db && db < obj_end) {
            db++;
            char *vb = strstr(db, "\"value\": \"");
            if (vb && vb < obj_end) { vb += 10; char *vq = strchr(vb, '"'); if (vq && vq < obj_end) { size_t l = vq - vb; if (l > sizeof desc - 1) l = sizeof desc - 1; memcpy(desc, vb, l); desc[l] = 0; while (l > 0 && desc[l-1] == ' ') desc[--l] = 0; } }
          }
        }
      }
    }
    char sunrise[32]="", sunset[32]="", moonrise[32]="", moonset[32]="";
    extract_astronomy(day, obj_end, sunrise, sizeof sunrise, sunset, sizeof sunset, moonrise, sizeof moonrise, moonset, sizeof moonset);
    to_24h(sunrise, sizeof sunrise);
    to_24h(sunset, sizeof sunset);
    to_24h(moonrise, sizeof moonrise);
    to_24h(moonset, sizeof moonset);
    struct tm tm = {0};
    char fmt_date[32];
    if (strptime(date, "%Y-%m-%d", &tm)) { mktime(&tm); strftime(fmt_date, sizeof fmt_date, "%a %d %b", &tm); }
    else snprintf(fmt_date, sizeof fmt_date, "%s", date);
    char line[512];
    snprintf(line, sizeof line, "%s: %s\u00b0C %s (%s) | Sun %s - %s | Moon %s - %s",
        fmt_date, temp, cond, desc, sunrise, sunset, moonrise, moonset);
    collapse_spaces(line);
    size_t llen = strlen(line);
    size_t need = out_len + llen + 2;
    if (need > out_cap) {
      size_t new_cap = out_cap ? out_cap * 2 : 2048;
      if (new_cap < need) new_cap = need;
      char *tmp = realloc(out, new_cap);
      if (!tmp) { free(out); free(json); return NULL; }
      out = tmp;
      out_cap = new_cap;
    }
    if (out_len > 0) { out[out_len++] = '\n'; }
    memcpy(out + out_len, line, llen);
    out_len += llen;
    out[out_len] = 0;
    p = (char*)obj_end;
  }
  free(json);
  if (!out || out_len == 0) return NULL;
  return out;
}

/*
 * cmd_forecast - Handle the "!forecast [city] [full]" command.
 *
 * Fetches a 3-day weather forecast from wttr.in using the JSON API.
 * Delegates to fetch_forecast() for the standard summary, or
 * fetch_forecast_full() when "full" is passed as an argument. The full
 * mode includes weather description, sunrise/sunset, and moonrise/moonset
 * for each day, sent as separate IRC messages. Defaults to Berlin if no
 * city is specified. Rate-limited.
 *
 * Parameters:
 *   s            - The IRC session.
 *   msg          - The raw message text.
 *   reply_target - Channel or nick to reply to.
 *   src_nick     - The nick of the user who sent the command.
 *
 * Returns: 1 if matched, 0 otherwise.
 */
int cmd_forecast(Session *s, const char *msg, const char *reply_target, const char *src_nick) {
  if (strncmp(msg, "!forecast", 9) != 0) return 0;
  if (msg[9] != ' ' && msg[9] != '\0') return 0;
  if (rate_limit_check(src_nick, reply_target, current_userhost) < 0) return 1;
  char city[256], city_url[256];
  int full = 0;
  const char *rest = msg[9] == ' ' ? msg + 10 : "";
  while (*rest == ' ') rest++;
  char args[512];
  strncpy(args, rest, sizeof args - 1);
  args[sizeof args - 1] = 0;
  char *full_ptr = strstr(args, "full");
  if (full_ptr) {
    size_t plen = full_ptr - args;
    if (plen > 0 && args[plen - 1] == ' ') {
      full = 1;
      args[plen - 1] = 0;
    } else if (plen == 0) {
      full = 1;
      args[0] = 0;
    }
  }
  while (*args == ' ') { memmove(args, args + 1, strlen(args)); }
  size_t alen = strlen(args);
  while (alen > 0 && args[alen - 1] == ' ') { args[--alen] = 0; }
  normalize_city(args, city, sizeof city, city_url, sizeof city_url);
  if (full) {
    char *body = fetch_forecast_full(city_url, city);
    if (body) {
      char *line = strtok(body, "\n");
      while (line) {
        irc_reply(s, reply_target, src_nick, line);
        line = strtok(NULL, "\n");
        if (line) {
          struct timespec ts_msg = { .tv_sec = 0, .tv_nsec = 200000000 };
          nanosleep(&ts_msg, NULL);
        }
      }
      free(body);
    } else {
      irc_reply(s, reply_target, src_nick, "Forecast: could not fetch data");
    }
  } else {
    char *body = fetch_forecast(city_url, city);
    char resp[1024];
    if (body) {
      snprintf(resp, sizeof resp, "%s", body);
      free(body);
    } else {
      snprintf(resp, sizeof resp, "Forecast: could not fetch data");
    }
    irc_reply(s, reply_target, src_nick, resp);
  }
  log_stamp(); fprintf(stderr, CLR_MAGENTA "FORECAST %s from %s (full=%d):" CLR_RESET " %s\n", reply_target, src_nick, full, city);
  return 1;
}

#endif