from bs4 import BeautifulSoup as BS
import datetime
import re
from operator import sub

def dateparse(datetime_str):
    date = '%b %d, %Y'
    time = '%I:%M %p'
    try:
        return datetime.datetime.strptime(datetime_str,date)
    except ValueError:
        return datetime.datetime.strptime(datetime_str,time)
days = [None,'M','T','W','R','F',None]
simp_exceptions = ['Grade Mode']

def datetime2date_time(dtime,mode):
    if mode == 'date':
        return datetime.date(dtime.year,dtime.month,dtime.day)
    elif mode == 'time':
        return datetime.time(dtime.hour,dtime.minute,dtime.second)

def seconds_from_midnight(t):
    return t.hour*60**2+ t.minute*60+t.second

def parse_horz_row(headers,row):
    data = (col.text for col in row.find_all('td'))
    ret = {}
    time_data = dict(zip(headers,data))
    try:
        time_data['time']
    except KeyError as e:
        print(row)
        raise e
    if time_data['time'] == 'TBA':
        ret['time_range'] = None
    else:
        s,e = map(dateparse,time_data['time'].split(' - '))
        ret['time_range'] = (
            datetime2date_time(s,'time'),
            datetime2date_time(e,'time'),
            )
    s,e = map(dateparse,time_data['date range'].split(' - '))
    time_data['days'] = re.sub('[^{}]'.format(''.join(filter(bool,days))),'',time_data['days'])
    ret['days'] = sorted((days.index(time_data['days'][i]) for i in range(len(time_data['days']))))
    if len(ret['days']) > 0:
        class_start = (s.weekday()+1)%7
        start = ret['days'][0]
        s += datetime.timedelta(days=(start - class_start))

    ret['date_range'] = (
        datetime2date_time(s,'date'),
        datetime2date_time(e,'date'),
        )
    ret['location'] = time_data['where']
    return ret

class Class:
    def __init__(self, title, abrv, session,
        term,
        crn,
        instructor,
        grade_mode,
        credits,
        level,
        campus,
        time_range,
        date_range,
        days,
        location,
    lab=None):

        #name
        self.title = title
        self.abrv = abrv
        #time
        self.date_range = date_range
        self.days = days
        self.time_range = time_range
        #location
        self.location = location
        self.campus = campus
        #other
        self.session = session
        self.term = term
        self.crn = crn
        self.instructor = instructor
        self.grade_mode = grade_mode
        self.credits = credits
        self.level = level
        self.lab = lab
    # data is a list of two html tables
    @classmethod
    def scrape(cls,data):
        info,times = data
        # info
        title,abrv,session = info.find('caption').text.split(' - ')
        session = int(session)
        rows = info.find_all('tr')
        params = {}
        for row in rows:
            name = row.find('th').text.rstrip(':')
            data = re.sub(r'^ +|[\n\r\t]','',row.find('td').text)

            if name == 'Status':
                type,date = data.split(' on ')
                type = type.replace('*','')
                registration_date = dateparse(date)
            else:
                if name in simp_exceptions:
                    name = name.lower().replace(' ','_')
                else:
                    name = name.lower().split(' ')[-1]
                if name != 'instructor':
                    data = data.lower()
                try:
                    data = int(re.sub(r'\.\d+','',data))
                except:

                    pass
                params[name] = data
        # time
        headers,*data = times.find_all('tr')
        headers = list(header.text.lower() for header in headers.find_all('th'))
        if len(data) > 1:
            data,lab = map(lambda row: parse_horz_row(headers,row),data[:2])
            lab.update(params)
            lab = Class(title + " - Lab",abrv,session,**lab)

        else:
            lab = None
            data = parse_horz_row(headers,data[0])

        params.update(data)
        return Class(title,abrv,session,lab=lab,**params)
    def __repr__(self):
        return '{} on {}'.format(self.title,''.join(days[i] for i in self.days))
    @property
    def length(self):
        return datetime.timedelta(seconds = sub(
            seconds_from_midnight(self.time_range[1]),
            seconds_from_midnight(self.time_range[0]),
            ))


def get_classes(page):
    if not isinstance(page,BS):
        page = BS(page,'lxml')
    tables = page.find_all('table',attrs= {'class':'datadisplaytable'})
    groups = ((tables[i],tables[i+1]) for i in range(0,len(tables),2))
    return map(Class.scrape,groups)

if __name__ == "__main__":
    with open('schedule.html') as file:
        page = BS(file.read(),'lxml')
    classes = list(get_classes(page))
    for _class in classes:
        print(repr(_class),_class.date_range)