match_colleagues.R

library(tidyverse)

# running variable: use "test" for test data, "real" for real data, if present
running <- "real" # "real"

# week number
weekno <- 43



###### FUNCTIONS ######
previous_matches <- function(name){
  previous <- existing %>% 
    filter(Colleague == name) %>%
    unlist() %>%
    unname()
  previous <- previous[!is.na(previous)]
  return(previous)
}

remove_previous <- function(name, participants){
  previous <- previous_matches(name)
  available <- participants[!participants %in% c(name,previous)]
  if(length(available) == 0){
    available <- participants[participants != name]
    stop("No available matches for ", name, ".")
  }
  return(available)
}


divide_participants <- function(participants){
  # make the data frame to fill in
  matchdata <- NULL
  while(length(participants) > 1){
    # draw name 1
    name <- base::sample(participants, 1)
    # get available matches
    available <- remove_previous(name, participants)
    # select match
    match <- base::sample(available, 1)
    # remove from participants
    participants <- participants[!participants %in% c(name,match)]
    # save to df
    matchdata <- rbind(matchdata, c(name,match))
  }
  
  matchdata <- as.data.frame(matchdata)
  names(matchdata) <- c("first", "second")
  
  # last match
  if(length(participants > 0)){
    name <- participants[1]
    previous <- previous_matches(name)
    
    matchdata <- matchdata %>%
      mutate(
        third = case_when(!first %in% previous & !second %in% previous ~ name),
        third = case_when(!duplicated(third) ~ third)
      )
    # if the last match did not find a good spot...
    if(!name%in%matchdata$third){
      stop(paste0("Could not find a good group for last remaining participant, ", name, "."))
    }
  }
  return(matchdata)
}


###### PIPELINE ######

# read in the data
if(running == "test"){
  cat(paste0("Running the colleague matching script with TEST data for week ",weekno,".\n"))
  df <- read_csv("data/testdata_colleagues.csv")
  existing <- read_csv("data/testdata_matches.csv")
} else if(running == "real"){
  cat(paste0("Running the colleague matching script with REAL data for week ",weekno,".\n"))
  df <- read_csv("data/realdata_colleagues.csv")
  existing <- read_csv("data/realdata_matches.csv")
} else{
  stop("Make a choice between 'real' and 'test' in the variable 'running'.")
}



# select participants for this week
participants <- df %>% 
  select(Name, contains(as.character(weekno)))
participants <- participants[,"Name"][!is.na(participants[,2])] %>% unname()

# TODO: this simply does not create matches but does not rerun the function if there is an error.
matchdata <- NULL
while(is.null(matchdata)){
  tryCatch({matchdata <- divide_participants(participants)},
          error = function(e){print(e)})
}



# make directory if it does not yet exists
if(!dir.exists("matches")){
  dir.create("matches")
}
write_csv(matchdata, paste0("matches/matches_",lubridate::today(),".csv"))


# this week's match name
thisweek1 <- paste0(weekno,"_Match1")
thisweek2 <- paste0(weekno,"_Match2")

# add matches to the previous matches document
first <- matchdata %>%
  rename(Colleague = first,
         match = second)

second <- matchdata %>%
  rename(Colleague = second,
         match = first)

matches_for_existing <- bind_rows(first,second) %>%
  rename(!!thisweek1 := match)

# if there is one set of three, a second column needs to be added
if(ncol(matchdata) > 2){
  matches_for_existing <- matches_for_existing %>%
    rename(!!thisweek2 := third)
  
  third_match <- matchdata %>%
    filter(!is.na(third)) %>%
    rename(Colleague = third,
           !!thisweek1 := first,
           !!thisweek2 := second)
  
  matches_for_existing <- bind_rows(matches_for_existing,third_match)
}

existing <- full_join(existing, matches_for_existing, by="Colleague")

# save the matches to 'existing matches' data
if(running == "test"){
  cat(paste0("Saving the matches with TEST data."))
  write_csv(existing, "data/testdata_matches.csv")
} else if(running == "real"){
  cat(paste0("Saving the matches with REAL data."))
  write_csv(existing, "data/realdata_matches.csv")
} else{
  stop("Make a choice between 'real' and 'test' in the variable 'running'.")
}