hattrupbasket: calculate advanced basketball stats

#################################################
# hattrupbasket
# functions
#################################################

#install.packages('gsheet')
library(gsheet)
player.stats <- gsheet2tbl('https://docs.google.com/spreadsheets/d/1FaTwspItXw-xLlz4ybmDd157thSA9Mg5jQI1FKr5rGc/edit#gid=466906933')


all.seasons <- unique(player.stats$season)
all.players <- unique(player.stats$name)



#' @get /helloworld
helloworld <- function(){
  hw <- "hello world"
  return(hw)
}

#' @get /version
version <- function(){
  version <- "version 0.0.0.1"
  return(hw)
}

#' @get /about
helloworld <- function(){
  about <- "hattrupbasket is a lightweight api for advanced basketball statistics"
  return(about)
}


#' player stats -- playerstats()
#'
#' get player stats for specific season and competition
#'
#' @param team team
#' @param player player
#' @param season season
#' @param competition competition
#' @param type p for playoffs, r for regular season, rp for both
#' @return table
#' @export
#' @get /playerstats
playerstats <- function(team=all, player="all", season="all", competition="all", type="rp"){
  SEA <- season
  COM <- competition
  PLA <- player
  TEA <- team
  # check arguments
  #if (missing(player) == TRUE) stop("missing argument: '' (number of 2-pointers made)")
  # 
  #?subset
  if (SEA == "all"){SEA="2016-2017"} else if (SEA == "all"){SEA=all.seasons}
  if (TEA == "all"){TEA=all.teams}
  if (player == "all"){player=all.players}
  tab <- subset(data.player.stats , team == TEA, season == SEA, player == PLA, select = c(season, team, name, pos, G, MP))
  return(tab)
}








#' 2-Point Field Goal Percentage (2P\%) -- calc2Ppct()
#'
#' Calculate 2-point-percentage (2P\%) using the number of
#' sucessfull 2-pointer and total 2-point attempts
#' (2P/2PA)*100
#'
#' @param p2 total number of succesfull 2-pointers
#' @param p2a number of 2-point attempts
#' @param pct TRUE for percentage of 100, FALSE for fraction of 1 
#' @return 2P\% ( between 0 and 1 )
#' @export
#' @get /twopointpct
pct2p <- function(p2,p2a,pct=TRUE){
  # check arguments
  if (missing(p2) == TRUE) stop("missing argument: 'p2' (number of 2-pointers made)")
  if (missing(p2a) == TRUE) stop("missing argument: 'p2a' (number of 2-point attempts)")
  if (p2 < 0) stop("'p2' must be >= 0")
  if (p2a < 0) stop("'p2a' must be >= 0")
  if (p2 > p2a) stop("'p2' must be <= p2a")
  if (p2a == 0) warning("2-point attempts equals zero")
  # calc
  pct2p <- (p2/p2a)
  # format
  if(pct==TRUE){pct2p <- pct2p*100}
  # return
  if (p2a == 0) {
    return(1)
  } else {
    return(pct2p)
  }
}

#' #' 3-Point Field Goal Percentage (3P\%) -- calc3Ppct()
#' #'
#' #' Calculate 3-point-percentage (3P\%) using the number of
#' #' sucessfull 3-pointer and total 3-point attempts
#' #' (3P/3PA)*100
#' #'
#' #' @param p3 total number of succesfull 2-pointers
#' #' @param p3a number of 2-point attempts
#' #' @param pct TRUE for percentage of 100, FALSE for fraction of 1 
#' #' @return 3P\% ( between 0 and 1 )
#' #' @export
#' pct3p <- function(p3,p3a,pct=TRUE){
#'   # check arguments
#'   if (missing(p3) == TRUE) stop("missing argument: 'p3' (number of 3-pointers made)")
#'   if (missing(p3a) == TRUE) stop("missing argument: 'p3a' (number of 3-point attempts)")
#'   if (p3 < 0) stop("'p3' must be >= 0")
#'   if (p3a < 0) stop("'p3a' must be >= 0")
#'   if (p3 > p3a) stop("'p3' must be <= p3a")
#'   if (p3a == 0) warning("3-point attempts equals zero")
#'   # calc
#'   pct3p <- (p3/p3a)
#'   # format
#'   if(pct==TRUE){pct3p <- pct3p*100}
#'   # return
#'   if (p3a == 0) {
#'     return(NA)
#'   } else {
#'     return(pct3p)
#'   }
#' }

#' #' Field Goal Percentage (FG\%) -- pctFG()
#' #'
#' #' Calculate field-goal-percentage (FGP\%) using the number of 
#' #' sucessfull field goals and total field goal attempts
#' #' (FG/FGA)*100
#' #'
#' #' @param fg total number of field goals made (not points)
#' #' @param fga number of field goal attempts
#' #' @param pct TRUE for percentage of 100, FALSE for fraction of 1 
#' #' @return 3P\%
#' #' @export
#' FGpct <- function(fg,fga,pct=TRUE){
#'   # check arguments
#'   if (missing(fg) == TRUE) stop("missing argument: 'fg' (number of field-goals made)")
#'   if (missing(fga) == TRUE) stop("missing argument: 'fga' (number of field-goal-attempts)")
#'   if (fg < 0) stop("'fg' must be >= 0")
#'   if (fga < 0) stop("'fga' must be >= 0")
#'   if (fg > fga) stop("'fg' must be <= fga")
#'   if (fga == 0) warning("field-goal-attempts equals zero")
#'   # calc
#'   FGpct <- (fg/fga)
#'   # format
#'   if(pct==TRUE){pctFG <- FGpct*100}
#'   # return
#'   if (fga == 0) {
#'     return(NA)
#'   } else {
#'     return(FGpct)  
#'   }
#' }
#' 
#' #' effective Field Goal Percentage (eFG%) -- eFGpct()
#' #'
#' #' Calculate effective/adjusted field-goal-percentage (FGP%) using the number of 
#' #' sucessfull field goals and total field goal attempts
#' #' ((FG+0.5*3P)/FGA)*100
#' #'
#' #' @param fg total number of field goals made (not points)
#' #' @param fga number of field goal attempts
#' #' @param p3 number of 3-pointers made
#' #' @param pct TRUE for percentage of 100, FALSE for fraction of 1 
#' #' @return 3P\%
#' #' @export
#' eFGpct <- function(fg,fga,p3,pct=TRUE){
#'   # check arguments
#'   if (missing(fg) == TRUE) stop("missing argument: 'fg' (number of field-goals made)")
#'   if (missing(fga) == TRUE) stop("missing argument: 'fga' (number of field-goal-attempts)")
#'   if (fg < 0) stop("'fg' must be >= 0")
#'   if (fga < 0) stop("'fga' must be >= 0")
#'   if (p3 < 0) stop("'p3' must be >= 0")
#'   if (fg > fga) stop("'fg' must be <= fga")
#'   if (p3 > fga) stop("'p3' must be <= fga")
#'   if (fga == 0) warning("field-goal-attempts equals zero")
#'   # calc
#'   eFGpct <- ((fg+0.5*p3/fga))
#'   # format
#'   if(pct==TRUE){eFGpct <- eFGpct*100}
#'   # return
#'   if (fga == 0) {
#'     return(NA)
#'   } else {
#'     return(eFGpct)  
#'   }
#' }



#' assist percentage (AST\%) -- ASTpct
#'
#' Calculate assist percentage - Assist percentage is an 
#' estimate of the percentage of teammate field goals 
#' a player assisted while he was on the floor.
#' 
#' the formula is 
#' AST / (((MP / (Tm MP / 5)) * Tm FG) - FG)
#' 
#'
#' @param AST total number of assists
#' @param MP Minutes Played
#' @param TmMP Total Minutes Played by Team
#' @param TmFG Total Number of Field Goals by team 
#' @param FG total number of field goals
#' @return AST\%
#' @export
# check arguments
# if (missing(AST) == TRUE) stop("missing argument: 'AST' (assists)")
# if (missing(MP) == TRUE) stop("missing argument: 'MP' (minutes played)")
# if (missing(TmMP) == TRUE) stop("missing argument: 'MP' (minutes played)")
# if (missing(TmFG) == TRUE) stop("missing argument: 'TmFG' (team minutes played)")
# if (missing(FG) == TRUE) stop("missing argument: 'FG' (field goals)")
# if (AST < 0) stop("'AST' must be >= 0")
# if (MP < 0) stop("'MP' must be >= 0")
# if (TmMP < 0) stop("'TmMP' must be >= 0")
# if (fg > fga) stop("'fg' must be <= fga")
# if (p3 > fga) stop("'p3' must be <= fga")
# if (fga == 0) warning("field-goal-attempts equals zero")
# ASTpct <- function(AST,
#                    MP,
#                    TmMP,
#                    TmFG,
#                    FG,
#                    pct=TRUE){
#   if(pct==TRUE){
#     ASTpct <- (AST/(((MP/(TmMP/5))*TmFG)-FG))*100
#   }
#   else {
#     ASTpct <- (AST/(((MP/(TmMP/5))*TmFG)-FG))
#   }
#   return(ASTpct)
# }