'''
Created on 31.10.2012

@author: dwinter
'''

import web
import random

ALREADY_EXISTS=0
NEW_PURL=1
ERROR=-1
PURL_PREFIX="MPIWG:"
    
class IndexMetaPURLManager:
    
    # register a new path to htmk
    # should start with  /mpiwg/online/ oder direct mit /permanent/ oder /archive/
    # return tuple:  status, result
    
    purlDB=None
    # DB has fields:
    # purl purl
    # path url or path to indexMeta
    # is_Index_meta bolean
    # created_by
    # created_at
    # last_change
    # validity 1 if it is valid, 0 if temporary invalid, -1 if permanetly invalid
    # server_url base_url of server
  
    def __init__(self):
        self.purlDB = web.database(dbn="postgres", db="purlDB",user="purlUSER",password="p*lWa55eR",host="localhost")
      
    
    
    def getPath(self,purl):  
        urls = self.purlDB.select('"purls"' ,where="purl='%s'"%purl)
        if urls is None or len(urls)==0:
            return None
        else:
            return urls[0]['path']
          
    #get purl attached tp a path or URL, return None if none.
    
    #checke if purl exist
    def exists(self,purl):
        if self.getPath(purl)==None:
            return False
        return True
            
    
    def getPurl(self,path):  
        #urls = self.purlDB.select('"purls"',where="path=%s"%web.sqlquote(path.replace("'"))
        urls = self.purlDB.query("select * from purls where path=$path",vars={'path':path})
        if urls is None or len(urls)==0:
            return None
        else:
            return urls[0]['purl']
        
    
    def generatePurl(self):
        
        
        driEncode={ 0:'0',
                    1:'1',
                    2:'2',
                    3:'3',
                    4:'4',
                    5:'5',
                    6:'6',
                    7:'7',
                    8:'8',
                    9:'9',
                    10:'A',
                    11:'B',
                    12:'C',
                    13:'D',
                    14:'E',
                    15:'F',
                    16:'G',
                    17:'H',
                    18:'K',
                    19:'M',
                    20:'N',
                    21:'P',
                    22:'Q',
                    23:'R',
                    24:'S',
                    25:'T',
                    26:'U',
                    27:'V',
                    28:'W',
                    29:'X',
                    30:'Y',
                    31:'Z'
                    }
        
        random.seed()
        x=[]
        for i in range(7):
            x.append(random.randint(0,31))

        sm=0
        for i in range(7):
            sm+=(i+1)*x[i]
            
        c=sm % 31
        nid=""
        for i in range(7):
            nid+=driEncode[x[i]]
        nid+=driEncode[c]
        return PURL_PREFIX+nid
        

        
    
    #generate purl and add it to the database
    def createPurl(self,path,isIndexMeta,server_url="",user=""):
        
        purl = self.generatePurl()
        
        #erzeuge eine neue purl
        while self.exists(purl):
            purl = self.gneratePurl()
        
        
        seq= self.purlDB.insert('purls',path=path,purl=purl,is_index_meta=isIndexMeta,
                                server_url=server_url,validity=1,created_by=user,created_at=web.SQLLiteral("NOW()"))
        
        
        return purl
        
    #register a new path
    def register(self,path,isIndexMeta,server_url="",user=""):
        
        
        #teste ob es zu dem Pfad schon eine Purl gibt
        purl = self.getPurl(path)
        if purl!=None:
            return ALREADY_EXISTS,purl
        
        
        #wenn nicht dann neue erzeugen
        else:
            purl = self.createPurl(path,isIndexMeta,user=user,server_url=server_url)
            if purl!=None:
                return NEW_PURL,purl
        
            else:
                return ERROR,None




if __name__ == '__main__':
    
    im = IndexMetaPURLManager()
    print im.register("/tmp3/index.meta", True, "", "dwinter")
    pass