# current version: 1.2.0
# last update: November 19, 2009

# load the Tcl/Tk library

require(tcltk)

# create main GUI

base = tktoplevel()
tkwm.title(base,'Wikipedia revision sizes')

# create main frame

nfrm = tkframe(base)

# create Tcl variables

revisions.tcl = tclVar('')
page.tcl = tclVar('')

# create "Page" text field

f1 = tkframe(nfrm)
tkpack(tklabel(f1, text = 'Page'), side = 'left')
tkpack(tkentry(f1, width = 25, textvariable = page.tcl), side = 'left')

# create "Revisions" text field

f2 = tkframe(nfrm)
tkpack(tklabel(f2, text = 'Revisions'), side = 'left')
tkpack(tkentry(f2, width = 8, textvariable = revisions.tcl), side = 'left')

# pack GUI elements

tkpack(f1, side='top')
tkpack(f2, side='top')
tkpack(nfrm)

# language code
# complete list available at http://meta.wikimedia.org/wiki/List_of_Wikipedias

lang = 'en'

# get page revision sizes

getpage = function(...) {
  revisions = as.numeric(tclvalue(revisions.tcl))
  page = as.character(tclvalue(page.tcl))
  page.loc = gsub(' ', '_', page) # fix space parsing
  ge = function(s, g) substring(s, g, g + attr(g, 'match.length') - 1)
  byte.pat = '<span class="history-size">(\\([0-9bytesmtp ,]+\\))</span>'
  historylink = paste('http://', lang, '.wikipedia.org/w/index.php?title=', page.loc, '&limit=', as.character(revisions), '&action=history', sep='')
  history = readLines(historylink)
  if (any(grep('no revision history', history))) {
    tkmessageBox(title = 'Error', message = 'This page does not exist!', type = 'ok')
} else {
  revisiondata = gsub(byte.pat, '\\1', mapply(ge, history[grep(byte.pat, history)], gregexpr(byte.pat, history[grep(byte.pat, history)], ignore.case = TRUE)), ignore.case = TRUE)
  revisiondata = as.character(revisiondata)
  revisiondata = gsub('[\\(\\), ]', '', revisiondata)
  for (a in 1:length(revisiondata)) {
    if (revisiondata[a] == 'empty') {revisiondata[a] = '0'}
  }
  revisiondata = gsub('[bytes]', '', revisiondata)
  revisiondata = as.numeric(revisiondata, ignore.na = TRUE)
  revisiondata = rev(revisiondata)
  plot(revisiondata, xlab = 'Revision index', ylab = paste('Revision size of \"', page, '\" (bytes)', sep = ''), type = 'l')
  }
}

# quit program

destroy = function(...) tkdestroy(base)

# create buttons

bfrm = tkframe(base)
tkpack(tkbutton(bfrm, text = 'Run', command = getpage), side = 'left')
tkpack(tkbutton(bfrm, text = 'Quit', command = destroy), side = 'right')

# pack bottom frame

tkpack(bfrm, side = 'bottom')