#!/usr/bin/python

import os
from datetime import timedelta,datetime
import dateutil.parser as dparser

class Filter:
    def __init__(self, in_str, delta):
        self.in_str = in_str
        self.delta = delta

    def filter(self, snapshots):
        return filter(self._filter, snapshots)

    def _filter(self, s):
        if self.in_str in s:
            ds = dparser.parse(s.replace("mx01","mxXX").replace("G0","go"), fuzzy=True)
            return (datetime.now()+self.delta) > ds
        return True

def filter_order(snapshots, word_list = ["hourly", "daily", "weekly", "monthly"]):
    ds = ""
    ds_pos = 0
    snapshots_ret = []
    snapshots.reverse()
    for a in snapshots:
        ds_a = a.split("@")[0]
        if ds != ds_a:
            ds = ds_a
            ds_pos = 0
        for idx,item in enumerate(word_list):
            if item in a:
                if ds_pos <= idx:
                    ds_pos = idx
                else:
                    snapshots_ret.append(a)
                    break;
    snapshots_ret.reverse()
    return snapshots_ret

def zfs_destroy(name):
    cmd = f"zfs destroy {name}"
    print(cmd)
    stream = os.popen(cmd)
    print(stream.read())

snapshots = []

try:
    with open("zfs-snaphosts.txt", "r") as f:
        snapshots = [l.strip() for l in f.readlines()]
except IOError:
    print("read live")
    stream = os.popen('zfs list -r -t snapshot -o name')
    snapshots = stream.read().split()[1:]

for a in filter_order(snapshots):
    zfs_destroy(a)

f = Filter("hourly", timedelta(hours=-25))
snapshots = list(f.filter(snapshots))

f = Filter("daily", timedelta(days=-8))
snapshots = list(f.filter(snapshots))

f = Filter("weekly", timedelta(weeks=-5))
snapshots = list(f.filter(snapshots))


for a in filter(lambda s: "znap" in s and not "monthly" in s, snapshots):
    zfs_destroy(a)