/usr/bin/python3
# ===================================================================
# data store class
# -------------------------------------------------------------------
# data store records are CSV strings. The first field is the record
# ID. The next fields are data. The record ID is an integer in
# string format (with start/end spaces removed).
# ===================================================================

import time

class DataStore:

    def __init__(self,latency=0.0):
        self.ds = {}
        self.latency = latency

    def add(self,id,rec):
        if id in self.ds:
            return False
        self.ds[id] = rec
        return True

    def delete(self,id):
        if id not in self.ds.keys():
            return False
        del self.ds[id]
        return True

    def fetch(self,id):
        if self.latency > 0.0:
            time.sleep(self.latency)
        if id not in self.ds.keys():
            return None
        return self.ds[id]

    def change(self,id,rec):
        self.ds[id] = rec
        return True

    def count(self):
        return len(self.ds.keys())

    def clear(self):
        c = self.count()
        self.ds = {}
        return c

    def set_fetch_latency(self,newlat):
        try:
            n = float(newlat)
        except:
            return False
        if n < 0.0 or n > 0.5:
            return False
        self.latency = n
        return True

    def get_fetch_latency(self):
        return self.latency

    def dump(self,limit=10):
        c  = 0
        for k in self.ds.keys():
            print(f'[{k:3}]  {self.ds[k]}')
            c += 1
            if c >= limit:
                break
        return c

    def dump99(self):
        print(self.ds)

# -------------------------------------------------------------------
# ---- main
# -------------------------------------------------------------------

if __name__ == '__main__':

    def create_test_data(db):
        db.add('1','1,abc,def')
        db.add('2','2,ghi,jkl')
        db.add('3','3,lmn,opq')
        db.add('4','4,rst,uvw,xyz')
        return 4

    import user_interface as ui

    db = DataStore()

    create_test_data(db)

    while True:

        # ---- menu

        ui.clear_screen()
        print('------test data store-----')
        print('option  description')
        print('------  ------------------')
        print('  1     add    DB entry')
        print('  2     delete DB entry')
        print('  3     fetch  DB entry')
        print('  4     change DB entry')
        print('  5     clear  DB')
        print('  6     set fetch latency')
        print('  7     get fetch latency')
        print(' 10     DB entry count')
        print(' 11     dump DB')
        print(' 12     load test data')
        print(' 13     exit program')

        # ---- get user input

        print()
        s = ui.get_user_input('  enter menu option: ')

        if not s:                           # empty string
             break

        tf,i = ui.is_integer(s)
        if not tf:
            print()
            print('input option error')
            ui.pause()
            continue

         # ---- process selection

        if i == 1:                          # add DB entry
            print()
            msg = 'DB records are a CSV strings with the first\n' +\
                  'field the ID (DB records and IDs are strings)'
            print(msg)
            print()
            rec = ui.get_user_input('  Enter DB record (CSV): ')
            if not rec:
                print()
                print('nothing entered')
                ui.pause()
                continue
            lst = rec.split(',',1)
            id = lst[0].strip()
            if not id:
                print()
                print('bad ID entered')
            elif not db.add(id,rec):
                print()
                print(f'ID {id} already in data store')
            ui.pause()
            continue

        if i == 2:                          # delete DB entry
            print()
            id = ui.get_user_input('  enter record ID: ')
            x = db.delete(id)
            print()
            if x:
                print('DB entry deleted')
            else:
                print('key not found')
            ui.pause()
            continue

        if i == 3:                          # fetch DB entry
            print()
            id = ui.get_user_input('  enter record ID: ')
            if not id:
                print()
                print(f'no ID entered')
                ui.puse()
                continue
            rec = db.fetch(id)
            print()
            if rec is None:
                print(f'DB record "{id}" not found')
            else:
                print(f'DB record is "{rec}"')
            ui.pause()
            continue

        if i == 4:                          # change DB entry
            print()
            msg = 'DB entries are a CSV strings with the first\n' +\
                  'field the ID (DB entries and IDs are strings)'
            print(msg)
            print()
            rec = ui.get_user_input('  enter DB record: ')
            if not rec:
                print()
                print('nothing entered')
                ui.pause()
                continue
            lst = rec.split(',',1)
            id = lst[0].strip()
            if not id:
                print()
                print('bad ID entered')
            else:
                db.change(id,rec)
            ui.pause()
            continue

        if i == 5:                          # clear DB of entries
            c = db.clear()
            print()
            print(f'{c} entries deleted')
            ui.pause()
            continue

        if i == 6:                          # set fetch latency
            print()
            s = ui.get_user_input('  enter fetch latency (0.0 to 0.5): ')
            if not s:
                print()
                print('nothing entered')
                ui.pause()
                continue
            tf,f = ui.is_float(s)
            if not tf:
                print()
                print(f'bad latency value {s}')
                ui.pause()
                continue
            tf = db.set_fetch_latency(f)
            if not tf:
                print()
                print(f'set latency failed')
            ui.pause()
            continue

        if i == 7:                         # get fetch latency
            l = db.get_fetch_latency()
            print()
            print(f'fetch latency is {db.get_fetch_latency():.4}')
            ui.pause()
            continue


        if i == 10:                         # DB count
            print()
            print(f'count = {db.count()}')
            ui.pause()
            continue

        if i == 11:                         # DB dump
            print()
            c = db.dump()
            print()
            print(f'dump count = {c}')
            ui.pause()
            continue

        if i == 12:                         # load test data
            c = create_test_data(db)
            print()
            print(f'{db.count()} DB entries')
            ui.pause()
            continue

        if i == 13:                         # exit program
            break

        if i == 99:                         # 'raw' data dump
            print()
            db.dump99()
            ui.pause()
            continue

        # ---- selection error

        print(f'unknow selection {i} entered')
        ui.pause()
    print()