#!/usr/bin/python
# Process a marking file that I've written.
# Adam Sampson <ats@offog.org>

import sys, os, re, csv, optparse, m25, random
from cStringIO import StringIO
from safefiles import read_file, write_file

def load_attendance(fn):
	student_info = {}

	key = None
	for row in csv.reader(open(fn, 'rb'), dialect='excel-tab'):
		if row[0] == "Number":
			key = {}
			for i in range(len(row)):
				key[i] = row[i].replace(" ", "_")
		elif row[0] == "" or key is None:
			continue
		elif row[0][0] in "0123456789":
			info = {}
			for i in range(len(row)):
				info[key[i]] = row[i]
			student = info["Forenames"].split()[0] + " " + info["Surname"]
			student_info[student] = info

	return student_info

def main():
	parser = optparse.OptionParser(usage="usage: %prog [options] INPUTFILE")
	parser.add_option("-a", dest="attendance",
	                  help="TSV file with attendance information")
	parser.add_option("-d", dest="outputdir", default="asst",
	                  help="output directory")
	parser.add_option("-t", dest="template", default="template",
	                  help="m25 template file for email")
	parser.add_option("-g", dest="generate", action="store_true",
	                  help="generate shuffled list of students; args are sections")
	(options, args) = parser.parse_args()

	if options.attendance:
		student_info = load_attendance(options.attendance)
	else:
		student_info = {}

	if options.generate:
		students = student_info.keys()
		random.shuffle(students)

		for name in students:
			sys.stdout.write("# %s\n\n" % name)
			for heading in args:
				sys.stdout.write("## %s (0)\n\n" % heading)

		return

	feedback = {}
	sections = []
	scores = {}
	section_feedback = {}
	computed = []
	exprs = {}

	if len(args) != 1:
		parser.error("must specify one input file")

	f = StringIO()
	m25.expand_file(args[0], f)
	f.seek(0)

	line = 0
	def warn(*s):
		print >>sys.stderr, "%d: %s" % (line, "".join(map(str, s)))
	def die(*s):
		warn(*s)
		sys.exit(1)

	student = None
	section = None
	while True:
		line += 1
		l = f.readline()
		if l == "":
			break
		l = l.rstrip()

		m = re.match(r'^# (.*)$', l)
		if m is not None:
			student = m.group(1)
			if student in feedback:
				die("Seen student already: ", student)
			feedback[student] = []
			section = None

		m = re.match(r'^#(=|\$) ([^:]+):(.*)$', l)
		if m is not None:
			name = m.group(2).strip()
			expr = m.group(3).strip()
			if m.group(1) == "=":
				computed.append(name)
			exprs[name] = expr
			continue

		if student is None:
			continue

		m = re.match(r'^## (.*) \(([^)]+)\)$', l)
		if m is not None:
			section = m.group(1)
			score = m.group(2)

			if section not in sections:
				sections.append(section)
			t = scores.setdefault(section, {})
			if student in t:
				die("Seen section for student already: ", student, ", ", section)
			t[student] = score
			t = section_feedback.setdefault(section, {})
			t[student] = []

		feedback[student].append(l)
		if section is not None and not l.startswith("#"):
			section_feedback[section][student].append(l)

	f.close()

	def student_key(student):
		info = student_info.get(student)
		if info is None:
			# No info for this student -- sort on the full name.
			return student
		else:
			# Sort by surname first.
			return info["Surname"] + " " + info["Forenames"]
	students = sorted(feedback.keys(), key=student_key)

	for student in students:
		if len(student_info) != 0 and student not in student_info:
			warn("No student info: ", student)
		for compute in computed:
			e = exprs[compute]
			def get(m):
				var = m.group(1)
				if var in scores and student in scores[var]:
					v = scores[var][student]
					if v in exprs:
						v = exprs[v]
				elif student in student_info and var in student_info[student]:
					v = student_info[student][var]
				else:
					warn("Student ", student, " missing variable ", var, "; using 0")
					v = "0"
				return str(float(v))
			s = re.sub(r'\$([A-Za-z_]+)', get, e)
			t = scores.setdefault(compute, {})
			t[student] = str(int(eval(s) + 0.5))
	sections += computed

	stuw = max([len(s) for s in students]) + 2
	colw = max([len(s) for s in sections]) + 1
	def pad(s, width):
		return (s + (" " * width))[:width]

	try:
		os.makedirs(options.outputdir + "/Feedback")
	except OSError:
		pass

	nl = "\r\n"

	o = open(options.outputdir + "/Marks.csv", "w")
	o.write(pad("Student", stuw) + ",")
	o.write(",".join([pad(s, colw) for s in sections]))
	o.write(nl)

	for student in students:
		o.write(pad(student, stuw))
		for s in sections:
			c = scores[s].get(student, "?")
			o.write("," + pad(c, colw))
		o.write(nl)
	o.write("Total %d students%s" % (len(students), nl))
	o.close()

	template = read_file(options.template)

	for student in students:
		ctx = m25.Context()

		info = student_info.get(student)
		if info is not None:
			ctx.define_literal("StudentNumber", info["Number"].split("/")[0])
		ctx.define_literal("Feedback", "\n".join(feedback[student]))
		for k, v in scores.items():
			ctx.define_literal(k, v[student])

		text = m25.expand_string(template, ctx)
		write_file(options.outputdir + "/Feedback/" + student + ".txt", text.replace("\n", nl))

	def quote(s):
		return s

	o = open(options.outputdir + "/Feedback.tsv", "w")

	o.write("Student")
	for s in sections:
		o.write("\t" + quote(s))
		if s in section_feedback:
			o.write("\t" + quote(s + " feedback"))
	o.write(nl)

	for student in students:
		o.write(quote(student))
		for s in sections:
			if student in scores[s]:
				score = str(scores[s][student])
			else:
				score = "?"
			o.write("\t" + score)

			if s in section_feedback:
				if student in section_feedback[s]:
					feedback = section_feedback[s][student]
				else:
					feedback = []
				fs = " ".join(feedback)
				fs = re.sub(r'\s+', ' ', fs).strip()
				o.write("\t" + quote(fs))
		o.write(nl)

	o.close()

if __name__ == "__main__":
	main()