import sys
import random

class Markov:
	def __init__(self):
		self.wlist = {}
		self.wstart = []
		self.fname = ""
	
	def addword(self, prev, curr, next):
		if curr in self.wlist:
			self.wlist[curr].append(next)
		else:
			self.wlist[curr] = [next]
		
		if not prev:
			self.wstart.append(curr)
	
	def parseline(self, line):
		l = line.lower().rstrip("\n").split(" ")
		p = c = n = None
		for w in l:
			if len(w) >= 1:
				p, c, n = c, n, w
				if c:
					self.addword(p,c,n)
		p, c, n = c, n, None
		while c:
			self.addword(p,c,n)
			p, c, n = c, n, None
	
	def parsefile(self, fname):
		fp = open(fname,"r")
		for o in fp:
			self.parseline(o)
		fp.close()
	
	def savedb(self, fname):
		fp = open(fname,"w")
		for o in self.wstart:
			if len(o) <= 0xFF:
				fp.write(chr(len(o)))
				fp.write(o)
		fp.write(chr(0))
		for o in self.wlist:
			if len(o) > 0xFF:
				o = o[:0xFF]
			fp.write(chr(len(o)))
			fp.write(o)
			for s in self.wlist[o]:
				if s == None:
					fp.write("\xFF")
				elif len(s) <= 0xFE:
					fp.write(chr(len(s)))
					fp.write(s)
				else:
					fp.write("\xFE")
					fp.write(s[:0xFE])
			fp.write(chr(0))
		fp.write(chr(0))
		fp.close()
	
	def loaddb(self, fname):
		fp = open(fname,"r")
		while True:
			l = ord(fp.read(1))
			if l == 0:
				break
			o = fp.read(l)
			self.wstart.append(o)
		while True:
			l = ord(fp.read(1))
			if l == 0:
				break
			o = fp.read(l)
			if not o in self.wlist:
				self.wlist[o] = []
			while True:
				l = ord(fp.read(1))
				if l == 0:
					break
				elif l == 0xFF:
					s = None
				else:
					s = fp.read(l)
				self.wlist[o].append(s)
		
		fp.close()
	
	def generate(self):
		w = self.wstart[int(random.random() * len(self.wstart))]
		s = w
		w = self.wlist[w][int(random.random() * len(self.wlist[w]))]
		while w:
			s += " " + w
			try:
				w = self.wlist[w][int(random.random() * len(self.wlist[w]))]
			except KeyError:
				s += " " + "KEYERROR"
				w = None
		
		return s

if __name__ == "__main__":
	if len(sys.argv) <= 1:
		print "usage:"
		print "  " + sys.argv[0] + " <filename ...>"
		print "prefix filenames with a : to read a database"
		raise SystemExit
	
	lib = Markov()
	for o in sys.argv[1:]:
		if o[0] == ':':
			print "Loading database \"" + o[1:] + "\"..."
			lib.loaddb(o[1:])
		else:
			print "Loading \"" + o + "\"..."
			lib.parsefile(o)
	print "Generating text..."
	s = lib.generate()
	print s