#!/usr/bin/python3

import datetime
import os
import socket

import psycopg2
import psycopg2.extras

hostname = socket.getfqdn()
db = psycopg2.connect('')
csr = db.cursor(cursor_factory=psycopg2.extras.DictCursor)

csr.execute(
        """
        with recursive
            t as (
                select '2 minutes'::interval as d
                union
                select d * 2 from t where d < '1 year'::interval
            ),
            fs as (
                select distinct hostname, filesystem
                    from df
                    where ts >= now() - '2 minutes'::interval
                    group by hostname, filesystem
            ),
            forecast as (
                select
                    fs.hostname, fs.filesystem,
                    new.ts + (new.ts - old.ts) as when,
                    new.ts + (new.ts - old.ts) - now() as d,
                    new.s_used + (new.s_used - old.s_used) as used,
                    (new.s_used + (new.s_used - old.s_used)) / old.s_usable * 100 as percent,
                    (new.s_used + (new.s_used - old.s_used)) > old.s_usable as capacity_exceeded
                from fs, t,
                    lateral (
                        select *
                        from df
                        where
                            df.hostname = fs.hostname
                            and df.filesystem = fs.filesystem
                            and df.ts >= now() - t.d
                        order by ts
                        limit 1
                    ) old,
                    lateral (
                        select *
                        from df
                        where
                            df.hostname = fs.hostname
                            and df.filesystem = fs.filesystem
                        order by ts desc
                        limit 1
                    ) new
            )
        select * from forecast
        where capacity_exceeded
        order by "when"
        """
)

status = 0
message = ""
for r in csr:
    if r["d"] < datetime.timedelta(hours=24):
        status = 2
    else:
        if status < 1:
            status = 1
    message += "%s:%s at %s; " % (r["hostname"], r["filesystem"], r["when"].strftime("%Y-%m-%d %H:%M"))
status_str = ["OK", "WARNING", "CRITICAL"]
print("df_space", status_str[status], "-", message)