#!/usr/bin/env r

## screen-scraped, eg for Chi 2007
#Dirk Eddelbuettel  |  Bib # 4367  |  River Forest, IL - CAN  |  Age 41  |  M
#START 		5K 		10K 		15K 		20K 		HALF 		25K 		30K 		35K 		40K 		FINISH
#0:01:05 	0:22:34 	0:45:30 	1:09:00 	1:34:27 	1:39:47 	2:00:05 	2:29:30 	2:58:45 	3:30:49 	3:41:39
#
#TIME 		Chip Time: 3:41:39 	Clock: 3:42:44 	Pace: 8:27
#Placement 	Overall: 1822 	Gender: 1461 	Division: 259

# 2008
# London under bib #53208
london08 <- c("0:22:12", "0:45:51", "1:09:42", "1:33:48", "1:57:57", "2:22:57", "2:49:07", "3:14:27", "3:24:41")

# 2007 ny 25k imputed
boston07 <- c("0:24:11", "0:48:34", "1:12:25", "1:37:17", "2:02:44", "2:28:28", "2:53:45", "3:17:59", "3:28:24")
chicago07 <- c("0:22:34", "0:45:30", "1:09:00", "1:34:27", "2:00:05", "2:29:30", "2:58:45", "3:30:49", "3:41:39")
newyork07 <- c("0:23:15", "0:46:48", "1:10:09", "1:33:38", "1:57:38", "2:21:39", "2:45:31", "3:09:17", "3:18:47")

# 2006
chicago06 <- c("0:23:04", "0:46:25", "1:09:30", "1:32:39", "1:56:11", "2:19:51", "2:44:15", "3:08:24", "3:18:49")

# 2005   15k 'imputed'
chicago05 <- c("0:23:38", "0:47:25", "1:10:30", "1:33:39", "1:57:42", "2:21:23", "2:46:13", "3:11:19", "3:21:36")

# 2004   5k guessed as half of 10k
chicago04 <- c("0:23:52", "0:47:43", "1:11:11", "1:34:56", "1:59:06", "2:24:33", "2:51:02", "3:18:05", "3:28:56")

## two quick helper functions
totsec <- function(x) {				# turns a character string of the form "0:22:33" into seconds
  times <- as.numeric(strsplit(x, ':')[[1]]) 	# split on ':', pick 1st set
  return(sum(times * c(60*60, 60, 1)))		# scale hours, mins, secs
}

totsec2pace <- function(totsec, distance=3.1) {	# turns total seconds in to pace as a real number
  totsecpermile <- totsec / distance		# so 7:45 comes out as 7.75 (ie 7 3/4)

  minpermile <- floor(totsecpermile/60)
  secpermile <- totsecpermile - minpermile*60

  pace <- minpermile + secpermile/60		# so that 7:30 becomes 7.5
  return(pace)
}


## convert all time-vectors to pace vectors
## forms ad-hoc list of data and uses lappy to loop over the list
## for each of the data vectors, we transform to seconds, then take differences
##   to get the per-5k-segment time and convert those into paces
## note how the vector is pre-padded with a zero to not drop the 1st in differencing
## and how the last segment from 40km to 42.195km is scaled up to 5km equivalent
paces <- lapply( list(chicago04, chicago05, chicago06, boston07, chicago07, newyork07, london08),
                function(x) sapply(diff(c(0, sapply(x, totsec))) * c(rep(1,8), 5/2.195),
                                   totsec2pace))

xvec <- c( seq(5,40,by=5), 42.195)

## combine into matrix, set row and col names
pacemat <- as.matrix(do.call("cbind", paces))
colnames(pacemat) <- c(paste("Chicago", 2004:2006), "Boston 2007", "Chicago 2007", "New York 2007", "London 2008")
rownames(pacemat) <- xvec

colvec <- c("darkblue", "mediumblue", "blue", "darkgreen", "lightblue", "orange", "yellow")


plotPaces <- function() {
  ## plot with some formatting and eye-candy
  opar <- par(bg="gray95", mar=c(4.25,4.5,3,1), las=1, lwd=1, cex.axis=0.9, cex.lab=0.9)
  ## set up plot region, titles, ... but don't actually plot (i.e. type='n')
  plot(xvec, pacemat[,1], ylim=range(pacemat), ylab="Pace in min/mile", type='n', yaxt="n", xaxt="n", pch=18,
       xlab="kilometer marker corresponding to endpoint of segment for which its average pace is shown",
       main="Pace per 5k segment in different marathon races")
  ## put some lightgray horizontol gridlines on the 30sec marks
  abline(h=seq(6.5, 10, by=0.5), col='lightgray')
  ## plot all races in a loop
  for (i in 1:ncol(pacemat)) lines(xvec, pacemat[,i], type='b', pch=14+i, col=colvec[i], lwd=2)
  ## pretty-print y-axis as usual "min:sec" paces, x-axis with km markers
  axis(2, at=seq(6.5, 10, by=0.5), labels=c("6:30", "7:00", "7:30", "8:00", "8:30", "9:00", "9:30", "10:00"))
  axis(1, at=xvec, labels=paste(round(xvec, digit=1),"k"))
  ## show a legend
  legend("topleft", legend=colnames(pacemat), bty="n", lwd=2, pch=15:19, col=colvec)
  ## restore plot defaults
  par(opar)
}

pngPlot <- function(filename="/tmp/london2008.png") {
  png(filename, width=800, height=600, pointsize=9)
  plotPaces()
  dev.off()
}

plotPaces()