import BaseHTTPServer
import pickle
import random
import math
import copy
import cgi
import time
import re
import threading
import urlparse
import sys
import decimal

HOST_NAME = 'localhost'
PORT_NUMBER = 4079

formula_templates = [
  {"name":"--TEMPLATE--", "disabled":True, "generateInputs":"return {'x':int(math.floor(random.random()*1000)), 'y':int(math.floor(random.random()*1000))}", "formula":"z=x+y", "problem":"What is z?", "resultTemplate":"%z%", "checkResult":"return (int(z) == int(x)+int(y))"},
]
formulae = []

def nl2br(s):
  return s.replace("\n", "<br>")

def tabifyCode(code):
  return "".join(["\t"+line+"\n" for line in code.split("\n")])

def generateFormula(formula_template=None):
  if formula_template == None:
    formula_templates_inuse = [i for i,v in enumerate(formula_templates) if not v["disabled"]]
    i = random.choice(formula_templates_inuse)
    formula_template = formula_templates[i]
  formula = {"template":copy.copy(formula_template), "solved":False}
  
  exec("def generateInputs():\n"+tabifyCode(formula_template["generateInputs"]))
  formula["inputs"] = generateInputs()
  
  formulae.append(formula)
  saveFormulae()
  return len(formulae)-1

def _checkResult(code, args):
  exec("def checkResult("+", ".join(args.keys())+"):\n"+tabifyCode(code))
  return checkResult(**args)

def checkResult(id, formula, params):
  values = {}
  for k,v in params.iteritems():
    if k == "template_id":
      continue
    k,i = k.rsplit("_", 1)
    v = v[0]
    if k in values:
      if v != values[k]:
        return False
    else:
      values[k] = v
  
  #TODO: Check we have all the values we need and no more
  
  formula["solved"] = _checkResult(formula["template"]["checkResult"], values)
  if formula["solved"]:
    def getValue(o):
      return values[o.group(1)]
    formula["solution"] = re.sub(r'%([a-zA-Z]+)%', getValue, formula["template"]["resultTemplate"])
    saveFormulae()
    return True
  return False

def editTemplate(id, formula_template, params):
  try:
    name = params["name"][0]
    disabled = params.has_key("disabled") and True or False
    generateInputs = params["generateInputs"][0]
    formula = params["formula"][0]
    problem = params["problem"][0]
    resultTemplate = params["resultTemplate"][0]
    checkResult = params["checkResult"][0]
    
    exec("def _generateInputs():\n"+tabifyCode(generateInputs))
    exec("def _checkResult():\n"+tabifyCode(checkResult))
    
    if params.has_key("test"):
      formula_template = {}
    formula_template["name"] = name
    formula_template["disabled"] = bool(disabled)
    formula_template["generateInputs"] = generateInputs
    formula_template["formula"] = formula
    formula_template["problem"] = problem
    formula_template["resultTemplate"] = resultTemplate
    formula_template["checkResult"] = checkResult
    if params.has_key("test"):
      return generateFormula(formula_template)
    
    saveFormulaTemplates()
    return True
  except:
    return False

def saveFormulae():
  try:
    f = file("formulae.pickle", "w")
    pickle.dump(formulae, f)
    f.close()
  except:
    print sys.exc_info()[0]

def saveFormulaTemplates():
  try:
    f = file("templates.pickle", "w")
    pickle.dump(formula_templates, f)
    f.close()
  except:
    print sys.exc_info()[0]

class MathHelperRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
  def do_GET(self):
    if self.path == "/":
      formula_templates_inuse = (i for i,v in enumerate(formula_templates) if not v["disabled"])
      for i in formula_templates_inuse:
        break
      else:
        self.send_response(302)
        self.send_header("Location", "/templates")
        self.send_header("Content-type", "text/html")
        self.end_headers()
        self.wfile.write("<html><head><title>Redirect</title></head><body><a href=\"/templates\">Redirect</a></body></html>")
      id = generateFormula()
      self.send_response(302)
      self.send_header("Location", "/formulae/%i" % id)
      self.send_header("Content-type", "text/html")
      self.end_headers()
      self.wfile.write("<html><head><title>Redirect</title></head><body><a href=\"/formulae/%i\">Redirect</a></body></html>" % id)
    
    elif self.path.startswith("/formulae/"):
      try:
        id = None
        incorrect = False
        template_id = None
        if self.path.endswith("/incorrect"):
          incorrect = True
        if (len(self.path.split("/")) == 5 or (incorrect and len(self.path.split("/")) == 6)) and self.path.split("/")[3] == "test":
          path = self.path.split("/")
          template_id = int(path[4])
          id = int(path[2])
        elif incorrect:
          id = int(self.path[10:-10])
        else:
          id = int(self.path[10:])
        formula = formulae[id]
      except (ValueError, IndexError):
        self.send_error(404)
        return
      self.writeFormula(id, formula, incorrect, template_id)
    
    elif self.path == "/formulae":
      self.writeFormulaList()
    
    elif self.path == "/templates":
      self.writeTemplateList()
    
    elif self.path.startswith("/templates/") and self.path.endswith("/test"):
      try:
        id = int(self.path[11:-5])
        formula_template = formula_templates[id]
      except (ValueError, IndexError):
        self.send_error(404)
        return
      
      formula_id = generateFormula(formula_template)
      self.send_response(302)
      self.send_header("Location", "/formulae/%i" % formula_id)
      self.send_header("Content-type", "text/html")
      self.end_headers()
      self.wfile.write("<html><head><title>Redirect</title></head><body><a href=\"/formulae/%i\">Redirect</a></body></html>" % formula_id)
    
    elif self.path.startswith("/templates/"):
      try:
        edited = False
        new = False
        invalid = False
        if self.path.endswith("/edited"):
          id = int(self.path[11:-7])
          edited = True
        elif self.path.endswith("/new"):
          id = int(self.path[11:-4])
          new = True
        elif self.path.endswith("/invalid"):
          id = int(self.path[11:-8])
          invalid = True
        else:
          id = int(self.path[11:])
        formula_template = formula_templates[id]
      except (ValueError, IndexError):
        self.send_error(404)
        return
      self.writeTemplateEditPage(id, formula_template, new, edited)
    
    elif self.path == "/style.css":
      self.writeCSS()
    
    elif self.path == "/quit":
      threading.Thread(target=self.server.shutdown).start()
      self.send_response(200)
      self.send_header("Content-type", "text/plain")
      self.end_headers()
      self.wfile.write("Server shutting down.")
    
    else:
      self.send_error(404)
  
  def do_POST(self):
    clen = -1
    try:
      clen = int(self.headers["Content-length"])
    except (ValueError, ValueError):
      pass
    params = urlparse.parse_qs(self.rfile.read(clen), True)
    
    if self.path.startswith("/formulae/") and self.path.endswith("/check-result"):
      try:
        id = int(self.path[10:-13])
        formula = formulae[id]
      except (ValueError, IndexError):
        self.send_error(404)
        return
      
      try:
        if params.has_key("template_id"):
          template_id = int(params["template_id"][0])
        else:
          template_id = None
      except (IndexError):
        self.send_error(404)
        return
      
      if checkResult(id, formula, params):
        if template_id != None:
          self.send_response(302)
          self.send_header("Location", "/templates/%i" % template_id)
          self.send_header("Content-type", "text/html")
          self.end_headers()
          self.wfile.write("<html><head><title>Redirect</title></head><body><a href=\"/templates/%i\">Redirect</a></body></html>" % template_id)
        else:
          self.writeCorrectResult()
      else:
        self.send_response(302)
        self.send_header("Location", "/formulae/%i/%sincorrect" % (id, template_id != None and ("test/%i/" % template_id) or ""))
        self.send_header("Content-type", "text/html")
        self.end_headers()
        self.wfile.write("<html><head><title>Redirect</title></head><body><a href=\"/formulae/%i/%sincorrect\">Redirect</a></body></html>" % (id, template_id != None and ("test/%i/" % template_id) or ""))
    
    elif self.path == "/templates/new":
      formula_templates.append(copy.copy(formula_templates[0]))
      id = len(formula_templates)-1
      formula_template = formula_templates[id]
      formula_template["disabled"] = True
      saveFormulaTemplates()
      self.send_response(302)
      self.send_header("Location", "/templates/%i/new" % id)
      self.send_header("Content-type", "text/html")
      self.end_headers()
      self.wfile.write("<html><head><title>Redirect</title></head><body><a href=\"/templates/%i/new\">Redirect</a></body></html>" % id)
    
    elif self.path.startswith("/templates/") and self.path.endswith("/edit"):
      try:
        id = int(self.path[11:-5])
        formula_template = formula_templates[id]
      except (ValueError, IndexError):
        self.send_error(404)
        return
      
      r = editTemplate(id, formula_template, params)
      if params.has_key("test") and r is not False:
        self.send_response(302)
        self.send_header("Location", "/formulae/%i/test/%s" % (r, id))
        self.send_header("Content-type", "text/html")
        self.end_headers()
        self.wfile.write("<html><head><title>Redirect</title></head><body><a href=\"/formulae/%i/test/%s\">Redirect</a></body></html>" % (r, id))
      elif r:
        self.send_response(302)
        self.send_header("Location", "/templates/%i/edited" % id)
        self.send_header("Content-type", "text/html")
        self.end_headers()
        self.wfile.write("<html><head><title>Redirect</title></head><body><a href=\"/templates/%i/edited\">Redirect</a></body></html>" % id)
      else:
        self.send_response(302)
        self.send_header("Location", "/templates/%i/invalid" % id)
        self.send_header("Content-type", "text/html")
        self.end_headers()
        self.wfile.write("<html><head><title>Redirect</title></head><body><a href=\"/templates/%i/invalid\">Redirect</a></body></html>" % id)
    
    else:
      self.send_error(404)
  
  def writeFormula(self, id, formula, incorrect, template_id):
    self.send_response(200)
    self.send_header("Content-type", "text/html")
    self.end_headers()
    
    self.wfile.write("<html><head><title>Formula #%i</title><link rel=\"stylesheet\" type=\"text/css\" href=\"/style.css\" /></head>" % id)
    self.wfile.write("<body><div id=\"wrapper\"><h1>Formula #%i</h1><form action=\"/formulae/%i/check-result\" method=\"POST\">" % (id, id))
    if incorrect:
      self.wfile.write("<p style=\"color:red;font-weight:bold;\" onclick=\"this.style.display='none'\">Incorrect solution.</p>")
    self.wfile.write("<p><label>Formula:</label> %s</p>" % nl2br(cgi.escape(formula["template"]["formula"])))
    self.wfile.write("<p><label>Inputs:</label> %s</p>" % "<br>".join(tuple("<strong>%s =</strong> %s" % (cgi.escape(k), cgi.escape(str(v))) for k,v in formula["inputs"].items())))
    self.wfile.write("<p><label>Problem:</label> %s</p>" % nl2br(cgi.escape(formula["template"]["problem"])))
    
    def sanitize(o):
      return cgi.escape(o.group(0))
    def _inc():
      i = 0
      while True:
        yield i
        i += 1
    inc = _inc()
    def makeInput(o):
      i = inc.next()
      return "<input type=\"text\" name=\"%s_%i\" style=\"width:4em\">" % (o.group(1), inc.next())
    answerform = formula["template"]["resultTemplate"]
    answerform = re.sub(r'(.*?)(?:%[a-zA-Z]%|$)', sanitize, formula["template"]["resultTemplate"])
    answerform = re.sub(r'%([a-zA-Z]+)%', makeInput, answerform)
    
    self.wfile.write("<p><label>Solution:</label> %s</p>" % nl2br(answerform))
    for k,v in formula["inputs"].iteritems():
      self.wfile.write("<input type=\"hidden\" name=\"%s_%i\" value=\"%s\">" % (k, inc.next(), str(v)))
    if template_id != None:
      self.wfile.write("<input type=\"hidden\" name=\"template_id\" value=\"%i\">" % template_id)
    self.wfile.write("<p><input type=\"submit\" value=\"Check\"> - <a href=\"/\">Skip</a></p>")
    self.wfile.write("</form><span style=\"float:right\"><a href=\"/templates\">View Templates</a> - <a href=\"/formulae\">View Previous Problems</a></span></body></html>")
  
  def writeFormulaList(self):
    self.send_response(200)
    self.send_header("Content-type", "text/html")
    self.end_headers()
    
    self.wfile.write("<html><head><title>Previous Problems</title><link rel=\"stylesheet\" type=\"text/css\" href=\"/style.css\" /></head>")
    self.wfile.write("<body><div id=\"wrapper\"><h1>Previous Problems</h1><table><thead><tr><th>ID</th><th>Formula</th><th>Inputs</th><th>Problem</th><th>Solution</th></tr></thead><tbody>")
    for i,formula in enumerate(formulae):
      self.wfile.write("<tr><td><a href=\"/formulae/%i\">%i</a></td><td>%s</td><td>%s</td><td>%s</td><td>%s</td></tr>" % (i, i, nl2br(cgi.escape(formula["template"]["formula"])), "<br>".join(tuple("<strong>%s =</strong> %s" % (cgi.escape(k), cgi.escape(str(v))) for k,v in formula["inputs"].items())), nl2br(cgi.escape(formula["template"]["problem"])), formula["solved"] and nl2br(cgi.escape(formula["solution"])) or "<a href=\"/formulae/%i\" style=\"color:red\">Not solved</a>" % i))
    self.wfile.write("</tbody></table><a href=\"/\" style=\"float:right\">Back</a></div></body></html>")
  
  def writeTemplateList(self):
    self.send_response(200)
    self.send_header("Content-type", "text/html")
    self.end_headers()
    
    self.wfile.write("<html><head><title>Formula Templates</title><link rel=\"stylesheet\" type=\"text/css\" href=\"/style.css\" /></head>")
    self.wfile.write("<body><h1>Formula Templates</h1><table><thead><tr><th>ID</th><th>Name</th><th>Input Generation Function</th><th>Formula</th><th>Problem</th><th>Solution Template</th><th>Solution Checking Function</th><th>Disabled?</th><th>Test</th></tr></thead><tbody>")
    for i,formula_template in enumerate(formula_templates):
      self.wfile.write("<tr><td><a href=\"/templates/%i\">%i</a></td><td><a href=\"/templates/%i\">%s</a></td><td><code>%s</code></td><td>%s</td><td>%s</td><td>%s</td><td><code>%s</code></td><td>%s</td><td><a href=\"/templates/%i/test\">Go</a></td></tr>" % (i, i, i, cgi.escape(formula_template["name"]), nl2br(cgi.escape(formula_template["generateInputs"])), nl2br(cgi.escape(formula_template["formula"])), nl2br(cgi.escape(formula_template["problem"])), nl2br(cgi.escape(formula_template["resultTemplate"])), nl2br(cgi.escape(formula_template["checkResult"])), formula_template["disabled"] and "<span style=\"color:red\">Yes</a>" or "<span style=\"color:green\">No</a>", i))
    self.wfile.write("</tbody></table>")
    self.wfile.write("<form action=\"/templates/new\" method=\"POST\"><input type=\"submit\" value=\"New Template\"></form>")
    self.wfile.write("<a href=\"/\" style=\"float:right\">Back</a></body></html>")
  
  def writeTemplateEditPage(self, id, formula_template, new=False, edited=True):
    self.wfile.write("<html><head><title>Template #%i - %s</title><link rel=\"stylesheet\" type=\"text/css\" href=\"/style.css\" /></head>" % (id, formula_template["name"]))
    self.wfile.write("<body><div id=\"wrapper\"><h1>Template #%i - %s</h1><form action=\"/templates/%i/edit\" method=\"POST\">" % (id, formula_template["name"], id))
    if new:
      self.wfile.write("<p style=\"color:green;font-weight:bold;\" onclick=\"this.style.display='none'\">New template.</p>")
    if edited:
      self.wfile.write("<p style=\"color:green;font-weight:bold;\" onclick=\"this.style.display='none'\">Successfully edited.</p>")
    self.wfile.write("<p><label>Name:</label> <input type=\"text\" name=\"name\" value=\"%s\"></p>" % cgi.escape(formula_template["name"]))
    self.wfile.write("<p><label>Input Generation Function:</label> <textarea name=\"generateInputs\">%s</textarea></p>" % cgi.escape(formula_template["generateInputs"]))
    self.wfile.write("<p><label>Formula:</label> <textarea name=\"formula\">%s</textarea></p>" % cgi.escape(formula_template["formula"]))
    self.wfile.write("<p><label>Problem:</label> <textarea name=\"problem\">%s</textarea></p>" % cgi.escape(formula_template["problem"]))
    self.wfile.write("<p><label>Solution Template:</label> <textarea name=\"resultTemplate\">%s</textarea></p>" % cgi.escape(formula_template["resultTemplate"]))
    self.wfile.write("<p><label>Solution Checking Function:</label> <textarea name=\"checkResult\">%s</textarea></p>" % cgi.escape(formula_template["checkResult"]))
    self.wfile.write("<p><label>Disabled:</label> <input type=\"checkbox\" name=\"disabled\" %s value=\"yes\"></p>" % (formula_template["disabled"] and "checked" or ""))
    self.wfile.write("<p><input type=\"submit\" value=\"%s\"> <input type=\"submit\" name=\"test\" value=\"Test\"></p>" % (new and "Create" or "Edit"))
    self.wfile.write("</form><a href=\"/templates\" style=\"float:right\">Back</a></div></body></html>")
  
  def writeCorrectResult(self):
    self.send_response(200)
    self.send_header("Content-type", "text/html")
    self.send_header("Refresh", "5;url=/")
    self.end_headers()
    
    self.wfile.write("<html><head><title>Correct Solution!</title><link rel=\"stylesheet\" type=\"text/css\" href=\"/style.css\" /></head>")
    self.wfile.write("<body><div id=\"wrapper\"><h1>Correct Solution!</h1><p><a href=\"/\">Click here</a> to go on to the next question.</p></div></body></html>")
  
  def writeCSS(self):
    self.send_response(200)
    self.send_header("Content-type", "text/css")
    self.end_headers()
    self.wfile.write("body{text-align:center;min-width:40%;} #wrapper{text-align:left;width:40%;margin-left:auto;margin-right:auto;} form p{width:40%;clear:left;margin:0;padding:5px 0 8px 0;padding-left:155px;border-top:1px dashed gray;min-height:2em;} form label{font-weight:bold;float:left;margin-left:-155px;width:150px;} form input[type=\"text\"]{width:180px;} form textarea{width:250px;height:150px;white-space:nowrap;overflow:auto;}")

try:
  f = file("templates.pickle", "r")
  formula_templates = pickle.load(f)
  f.close()
except:
  saveFormulaTemplates()

try:
  f = file("formulae.pickle", "r")
  formulae = pickle.load(f)
  f.close()
except:
  saveFormulae()

if __name__ == '__main__':
  server_class = BaseHTTPServer.HTTPServer
  httpd = server_class((HOST_NAME, PORT_NUMBER), MathHelperRequestHandler)
  print time.asctime(), "Server Starts - %s:%s" % (HOST_NAME, PORT_NUMBER)
  httpd.serve_forever()
  httpd.server_close()
  print time.asctime(), "Server Stops - %s:%s" % (HOST_NAME, PORT_NUMBER)