library(DBI)
library(tidyr)

con <- dbConnect(RPostgres::Postgres(), 
                 dbname='mainscnt', 
                 host='172.16.10.27', 
                 user='wn')

START <- "2021-08-02T14:00:00.0Z"
END <- "2021-08-02T15:00:00.0Z"

res <-dbSendQuery(con, "select time, location, freq from mainsfrequency where valid=1 and time >= $1 and time < $2")
dbBind(res, list(START, END))
frequencies <- dbFetch(res)
dbClearResult(res)

freq_wide <- frequencies %>% 
  pivot_wider(names_from = location, 
              values_from = freq, 
              values_fn = mean)


THRESHOLD <- 0.5

for (colIdx in 2:length(freq_wide)) {
  last <- freq_wide[[1, colIdx]]
  for (rowIdx in 1:length(freq_wide[[colIdx]])) {
    current <- freq_wide[[rowIdx, colIdx]]
    if (!is.na(current) && !is.na(last) && (abs(current - last) > THRESHOLD)) {
      freq_wide[[rowIdx, colIdx]] = NA
    }
    last <- current
  }
}


freq_wide <- freq_wide %>% 
  rowwise() %>% 
  mutate(mad = mad(c_across(names(freq_wide)[-1]), 
                   na.rm=TRUE))

# print(summary(freq_wide))
print(sum(freq_wide$mad) / length(freq_wide$mad))

dbDisconnect(con)