#!usr/bin/env python3
#_*_coding:utf-8_*_

'staff infomation management module'
__author__='Byron Li'

'''----------------------------------------------員工信息數(shù)據(jù)庫操作指令語法---------------------------------------------
數(shù)據(jù)記錄包含6個(gè)關(guān)鍵字：id,name,age,phone,dept,enroll_date
指令可用的邏輯運(yùn)算符：<,>,=,<=,>=,like,and,or,not
1.增（add to xxxx values xxxx）
 示例：add to staff_table values Alex Li,22,13651054608,IT,2013-04-01 
2.刪（delete from xxxx where xxxx）
 示例：delete from staff_table where age<=18 and enroll_date like "2017"
3.改(update xxxx set xxxx where xxxx)
 示例：update staff_table set dept="Market",age=30 where dept="IT" and phone like "189"
4.查(select xxxx from xxxx where xxxx)
 示例1：select * from staff_table where age>=25 and not phone like "136" or name like "李"
 示例2：select name,age,dept from db.txt where id<9 and enroll_date like "-05-"
 示例3：select * from staff_table where *   #顯示所有記錄
---------------------------------------------------------------------------------------------------------------------'''
import re
import os
class staff(object):    #員工類
 def __init__(self,*args):  #員工信息初始化：從字符串列表傳參賦值
  self.id=args[0]
  self.name=args[1]
  self.age=args[2]
  self.phone=args[3]
  self.dept=args[4]
  self.enroll_date=args[5]
  self.allinfo=','.join(args)
 def update(self,**kwargs):  #員工信息更新：從字典傳參賦值
  if 'id' in kwargs:
   self.id=kwargs['id']
  if 'name' in kwargs:
   self.name=kwargs['name']
  if 'age' in kwargs:
   self.age = kwargs['age']
  if 'phone' in kwargs:
   self.phone=kwargs['phone']
  if 'dept' in kwargs:
   self.dept=kwargs['dept']
  if 'enroll_date' in kwargs:
   self.enroll_date = kwargs['enroll_date']
  self.allinfo = ','.join(map(str,[self.id, self.name, self.age, self.phone, self.dept, self.enroll_date]))
 def print_info(self,info):  #員工信息打印顯示：傳入的參數(shù)為"*"或數(shù)據(jù)記錄的若干個(gè)關(guān)鍵字
  if info=='*':
   print(self.allinfo)
  else:
   info=info.split(',')
   res=[]
   for i in info:
    if hasattr(self,i.strip()):
     res.append(str(getattr(self,i.strip())))
   print(','.join(res))

def command_exe(command): #指令執(zhí)行主函數(shù)，根據(jù)指令第一個(gè)字段識別何種操作，并分發(fā)給相應(yīng)的處理函數(shù)執(zhí)行
 command=command.strip()
 return {
  'add':add,
  'delete':delete,
  'update':update,
  'select':search,
 }.get(command.split()[0],error)(command)

def error(command):  #錯誤提示函數(shù)，指令不合語法調(diào)用該函數(shù)報(bào)錯
 print('\033[31;1m語法錯誤，請重新輸入！\033[0m\n')

def add(command):  #增加員工記錄函數(shù)
 command_parse=re.search(r'add\s*?to\s(.*?)values\s(.*)',command) #正則表達(dá)式指令解析
 if(command_parse):
  data_file=command_parse.group(1).strip() #數(shù)據(jù)庫文件
  info=command_parse.group(2).strip()  #需新增的員工信息，不含id
  id=1          #新增員工id，默認(rèn)為1以防數(shù)據(jù)庫為空表時(shí)新增記錄id取1
  with open(data_file, 'r+', encoding='utf-8') as fr:
   line=fr.readline()
   while(line):
    if line.strip()=='':
     fr.seek(fr.tell()-len(line)-2) #定位文件最后一行(只有空字符)的開頭
     break
    staff_temp = staff(*line.strip().split(','))  #讀取的信息轉(zhuǎn)換為staff對象
    id = int(staff_temp.id) + 1   #末行員工id加1為新員工id
    line = fr.readline()
   info_new=''.join([str(id),',',info]) #id與其他信息合并成完整記錄
   fr.write(info_new)
   fr.write('\n')
   fr.flush()
   print("數(shù)據(jù)庫本次\033[31;1m新增1條\033[0m員工信息：", info_new) #新增記錄打印
 else:
  error(command)

def delete(command): #刪除員工記錄函數(shù)
 command_parse=re.search(r'delete\s*?from\s(.*?)where\s(.*)',command) #指令解析
 if(command_parse):
  data_file=command_parse.group(1).strip() #數(shù)據(jù)庫文件
  condition=command_parse.group(2).strip() #檢索條件
  data_file_bak = ''.join([data_file, '.bak'])
  count = 0   #刪除記錄計(jì)數(shù)
  staff_list = []  #刪除記錄的員工對象列表
  with open(data_file, 'r', encoding='utf-8') as fr, \
    open(data_file_bak, 'w', encoding='utf-8') as fw:
   for line in fr:
    staff_temp = staff(*line.strip().split(','))
    if (verify(staff_temp, condition)): #驗(yàn)證員工信息是否符合條件
     count+=1
     staff_list.append(staff_temp)
     continue
    fw.write(staff_temp.allinfo)
    fw.write('\n')
   fw.flush()
  os.remove(data_file)
  os.rename(data_file_bak, data_file)
  print("數(shù)據(jù)庫本次共\033[31;1m刪除%d條\033[0m員工信息，如下:"%count)
  for staff_temp in staff_list:
   staff_temp.print_info('*') #刪除記錄打印
 else:
  error(command)

def update(command):  #修改和更新員工記錄函數(shù)
 command_parse=re.search(r'update\s(.*?)set\s(.*?)where\s(.*)',command) #指令解析
 if(command_parse):
  data_file=command_parse.group(1).strip()  #數(shù)據(jù)庫文件
  info=command_parse.group(2).strip()   #需更新的信息
  condition=command_parse.group(3).strip()  #檢索條件
  data_file_bak=''.join([data_file,'.bak'])

  info = ''.join(['{', info.replace('=', ':'), '}']) #將需更新的信息按字典格式修飾字符串
  info = eval(re.sub(r'(\w+)\s*:', r'"\1":', info)) #將字符串進(jìn)一步修飾最終轉(zhuǎn)化成字典
  count = 0
  staff_list = []
  with open(data_file,'r',encoding='utf-8') as fr,\
    open(data_file_bak,'w',encoding='utf-8') as fw:
   for line in fr:
    staff_temp=staff(*line.strip().split(','))
    if(verify(staff_temp,condition)): #驗(yàn)證員工信息是否符合條件
     staff_temp.update(**info)  #調(diào)用員工對象成員函數(shù)更新信息
     count += 1
     staff_list.append(staff_temp)
    fw.write(staff_temp.allinfo)
    fw.write('\n')
   fw.flush()
  os.remove(data_file)
  os.rename(data_file_bak,data_file)
  print("數(shù)據(jù)庫本次共\033[31;1m更新%d條\033[0m員工信息，如下:"%count)
  for staff_temp in staff_list:
   staff_temp.print_info('*') #更新記錄打印
 else:
  error(command)

def search(command):  #查詢員工記錄函數(shù)
 command_parse=re.search(r'select\s(.*?)from\s(.*?)where\s(.*)',command) #指令解析
 if(command_parse):
  info=command_parse.group(1).strip()   #檢索結(jié)束后需顯示的信息，"*"為顯示整體記錄
  data_file=command_parse.group(2).strip() #數(shù)據(jù)庫文件
  condition=command_parse.group(3).strip() #檢索條件
  count = 0
  staff_list = []
  with open(data_file,'r',encoding='utf-8') as fr:
   for line in fr:
    staff_temp=staff(*line.strip().split(','))
    if(verify(staff_temp,condition)): #驗(yàn)證員工信息是否符合條件
     count += 1
     staff_list.append(staff_temp)
  print("數(shù)據(jù)庫本次共\033[31;1m查詢到%d條\033[0m員工信息，如下:" % count)
  for staff_temp in staff_list:
   staff_temp.print_info(info)  #查詢記錄打印
 else:
  error(command)

def verify(staff_temp,condition):    #員工信息驗(yàn)證函數(shù)，傳入一個(gè)員工對象和條件字符串
 if condition.strip()=='*':return True #如果條件為'*',即所有記錄都滿足條件
 condition_list=condition.split()   #檢索條件字符串轉(zhuǎn)列表
 if len(condition_list)==0:return False
 logic_str=['and','or','not'] #邏輯運(yùn)算字符串 且、或、非
 logic_exp=[]     #單個(gè)條件的邏輯表達(dá)式組成的列表，形如[‘a(chǎn)ge',' ','>','=',20] 或 [‘dept',' ','like',' ','HR']
 logic_list=[]     #每個(gè)條件的表達(dá)式的計(jì)算結(jié)果再重組后的列表，形如 [‘True','and','False','or','not','False']
 for i in condition_list:
  if i in logic_str:
   if(len(logic_exp)!=0):
    logic_list.append(str(logic_cal(staff_temp,logic_exp))) #邏輯表達(dá)式計(jì)算并將返回的True或False轉(zhuǎn)化成字符串添加到列表
   logic_list.append(i)
   logic_exp=[]
  else:
   logic_exp.append(i)
 logic_list.append(str(logic_cal(staff_temp, logic_exp)))
 return eval(' '.join(logic_list)) #列表轉(zhuǎn)化成數(shù)學(xué)表達(dá)式完成所有條件的綜合邏輯運(yùn)算，結(jié)果為True或False

def logic_cal(staff_temp,logic_exp): #單個(gè)邏輯表達(dá)式的運(yùn)算函數(shù)
 logic_exp = re.search('(.+?)([=<>]{1,2}|like)(.+)',''.join(logic_exp)) #表達(dá)式列表優(yōu)化成三個(gè)元素，形如[‘a(chǎn)ge','>=',20] 或 [‘dept','like','HR']
 if(logic_exp):
  logic_exp=list(logic_exp.group(1,2,3))
  if(hasattr(staff_temp,logic_exp[0])):
   logic_exp[0] = getattr(staff_temp,logic_exp[0])
  else:
   return False
  if logic_exp[1]=='=':  #指令中的'='轉(zhuǎn)化成程序中相等判別的"=="
   logic_exp[1]='=='
  if logic_exp[1]=='like':  #運(yùn)算符為like的表達(dá)式運(yùn)算
   return re.search(logic_exp[2].strip("'").strip('"'),logic_exp[0]) and True
  elif(logic_exp[0].isdigit() and logic_exp[2].isdigit()): #兩頭為數(shù)字的運(yùn)算，直接eval函數(shù)轉(zhuǎn)數(shù)學(xué)表達(dá)式
   return eval(''.join(logic_exp))
  elif(logic_exp[1]=='=='): #非數(shù)字的運(yùn)算，即字符串運(yùn)算，此時(shí)邏輯符只可能是‘='，若用eval函數(shù)則字符串會轉(zhuǎn)成無定義變量而無法計(jì)算，所以拿出來單獨(dú)用"=="直接計(jì)算
   return logic_exp[0]==logic_exp[2].strip("'").strip('"') #字符串相等判別，同時(shí)消除指令中字符串引號的影響，即輸引號會比記錄中的字符串多一層引號
  else:   #其他不合語法的條件格式輸出直接返回False
   return False
 else:
  return False

if __name__=='__main__':  #主函數(shù)，數(shù)據(jù)庫指令輸入和執(zhí)行
 while(True):
  command=input("請按語法輸入數(shù)據(jù)庫操作指令：") #指令輸入
  if command=='exit':
   print("數(shù)據(jù)庫操作結(jié)束，成功退出！".center(50, '*'))
   break
  command_exe(command)  #指令執(zhí)行