# Community Data Science Collective R Utilities
#
# Copyright (c) 2010-2016 Benjamin Mako Hill and Aaron Shaw 
# mako@atdot.cc, aaronshaw@northwestern.edu

# privileges of interest:
# a shared variable that gets used everywhere
generate.admin.addrm <- function (logevents, current.admins) {

  # convert types of a few variables
  logevents$ancient <- logevents$ancient == "true"
  logevents$timestamp <- timestamp.to.POSIXct(logevents$timestamp)
  logevents$rights.new[is.na(logevents$rights.new)] <- ""
  logevents$rights.old[is.na(logevents$rights.old)] <- ""

  # TODO do wikia wikis have these =?
  # in WP, all of these are negated by one day
  logevents <- logevents[!(logevents$ancient & logevents$comment == "="),]
  
  ##########################################
  ###  Parsing logevents file
  #########################################

  # separate out moderns & ancients and the necessary columns
  ancients <- logevents[logevents$ancient,c("title","comment","timestamp")]
  moderns <- logevents[!logevents$ancient,
                       c("title","rights.new","rights.old","timestamp")]
  
  # function that looks at rights.old, rights.new and returns a value of
  # privilege, add/remove, and timestamp for each user
  parse.moderns <- function (i, d) {
    user <- sub('^User:', "", d[i,"title"])
    change.time <- d[i,"timestamp"]
    rights.new <- d[i,"rights.new"]
    rights.old <- d[i,"rights.old"]
    
    # create a vector of new and old rights:
    destring <- function (x) { strsplit(as.character(x), ", ")[[1]] }

    # create a list of privileges that are mentioned
    privileges <- unique(c(destring(rights.new),
                           destring(rights.old)))

    # create T/F vectors incidating which privileges were added/removed
    added <- privileges[privileges %in% destring(rights.new) &
                        !(privileges %in% destring(rights.old))]
    removed <- privileges[!(privileges %in% destring(rights.new)) &
                          privileges %in% destring(rights.old)]

    # assemble the data frame of: role,action,user,timestamp
    data.frame(user=rep(user, length(c(added,removed))),
               role=c(added, removed),
               action=c(rep("added",length(added)),
                 rep("removed", length(removed))),
               timestamp=rep(change.time, length(c(added,removed))),
               era=rep("modern", length(c(added,removed))),
               stringsAsFactors=FALSE)
  }

  # if there are log events, and there are non-ancients (not all are ancients), we parse them
  if (dim(logevents)[1] & !all(logevents$ancient)) {
    moderns.parsed <- do.call("rbind",
                              lapply(1:dim(moderns)[1], parse.moderns, moderns))
  } else {
    moderns.parsed = NULL
  }
  
  # another function to handle processing the ancients:
  parse.ancient <- function (i, d) {
    user <- sub('^.*?:', '', d[i,"title"])
    comment <- d[i, "comment"]
    change.time <- d[i, "timestamp"]

    added <- unlist(strsplit(unlist(strsplit(comment, '(\\+|\\=)')), ', '))

    # clean any leadin, trailing whitespace
    added <- gsub("^\\s+|\\s+$", "", added)

    data.frame(user=user,
               role=added,
               action="added",
               timestamp=change.time,
               era="ancient",
               stringsAsFactors=FALSE)
  }

  # if there are any ancients, we parse them
  if (any(logevents$ancient)) {
    ancients.parsed <- do.call("rbind",
                               lapply(1:dim(ancients)[1], parse.ancient, ancients))
  } else {
    ancients.parsed = NULL
  }

  combined <- rbind(moderns.parsed, ancients.parsed)
  
  ##########################################
  ###  Parsing current.admins file
  #########################################
  # turn each of the columns after the first two into logical

  # function to process pre.ancients
  parse.current.admins <- function (i, d) {
    user <- d[i, "username"]
    roles <- gsub("^\\s+|\\s+$", "", strsplit(d[i, "groups"], ",")[[1]])

    o <- data.frame(user=user, role=roles, stringsAsFactors=FALSE)
    colnames(o) <- c("user", "role")
    return(o)
  }

  ## handle the case where there are no admins. This can happen on Wikipedia
  if(dim(current.admins)[1] != 0){
      current.admins.parsed <- do.call("rbind",
                                       lapply(1:dim(current.admins)[1],
                                              parse.current.admins, current.admins))
  }
  else{
      current.admins.parsed <- NULL
  }

  # select pre-ancients as people who have a given right *today* but
  # were never seen as having it added
  is.pre.ancients <- function (i, d, combined) {
    user <- d[i, "user"]
    role <- d[i, "role"]

    # look to see if we've see any events with this user and role added:
    # if we see none, this is pre-ancient
    !any(combined$user == user &
         combined$role == role &
         combined$action == "added")

  }

  if(!is.null(current.admins.parsed)){
  # create the list of pre-ancients (people role combinations we have
  # not seen in the logevents data
      pre.ancients <- current.admins.parsed[sapply(1:dim(current.admins.parsed)[1],
                                                   is.pre.ancients,
                                                   current.admins.parsed,
                                                   combined),]
  }
  else{
      pre.ancients <- NULL
  }

  # make a list of people who have been removed
  combined.removed <- combined[combined$action == "removed",]
  if (!is.null(combined.removed)) {
    if (dim(combined.removed)[1] > 0) {
      combined.removed <- combined.removed[sapply(1:dim(combined.removed)[1],
                                                  function (i,d) {
        user <- d[i,"user"]
        role <- d[i,"role"]
        timestamp <- d[i,"timestamp"]

        # was the person added before they were removed? OR in the pre-ancients
        any(combined$user == user &
            combined$role == role &
            combined$action == "added" &
            combined$timestamp <= timestamp) | (user %in% pre.ancients$user)
      }, combined.removed),c("user", "role")]
    }
  }

  
  pre.ancients <- rbind(pre.ancients, combined.removed)
  
  # give them the earliest ancient timestamp minus 1 day
  # and then add the pre.ancients to the 
  if(!is.null(pre.ancients)){
      pre.ancients$action <- "added"
      pre.ancients$timestamp <- as.POSIXct("2000-01-01 00:00:00") # min(combined$timestamp) - 60 * 1440
      pre.ancients$era <- "pre.ancient"

      combined <- rbind(combined, pre.ancients)
  }

  # remove redunandt actions
  combined <- combined[!duplicated(combined),]
  return(combined)
}