#!/usr/bin/python3

#### Config
repos = []
{% for r in config.repos %}
_hosts=[]
{% for h in r.hosts %}
_hosts.append("{{ h }}")
{% endfor %}
repos.append({
    "name": "{{ r.name }}",
    "url": "{{ r.url }}",
    "key": "{{ r.key }}",
    "hosts": _hosts,
    "cleanup_parameters": "{{ r.cleanup_parameters | default(config.default_cleanup_parameters) }}",
    "check_repo": {% if r.check_repo %}True{% else %}False{% endif %},
})
{% endfor %}

{% macro to_python(d) %}{
{% for key, value in d.items() %}
"{{ key }}": {% if value is boolean %}{% if value %}True{% else %}False{% endif %}{% elif value is mapping %}{{ to_python(value) }}{% else %}{{ value | tojson }}{% endif %},
{% endfor %}
}
{% endmacro %}

hosts = {{ to_python(config.hosts) }}
#### End config

import subprocess
import os
import sys
import json
import datetime
import time

import fcntl

lockfd = open("{{ homedir }}/.backupmanager.lock", "w")
try:
    fcntl.flock(lockfd, fcntl.LOCK_EX | fcntl.LOCK_NB)
except BlockingIOError:
    print("Another instance is running.")
    sys.exit(1)

def run_command(command, env=None):
    current_env = os.environ.copy()
    if env is not None:
        current_env.update(env)
    process = subprocess.run(command, shell=True, env=current_env)
    if process.returncode != 0:
        raise RuntimeError(f"Command '{command}' failed with return code {process.returncode}, environment is {env}")

def get_command(command, env=None, full_return=False):
    current_env = os.environ.copy()
    if env is not None:
        current_env.update(env)
    process = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True, env=current_env)
    output, error = process.communicate()
    return_code = process.poll()
    if full_return:
        return output.decode().strip(), error.decode().strip(), return_code
    if error:
        print(error.decode().strip(), file=sys.stderr)
    if return_code != 0:
        raise RuntimeError(f"Command '{command}' failed with return code {return_code}, environment is {env}")
    return output.decode()

def get_snapshot_info(repo):
    e = {}
    e["RESTIC_REPOSITORY"]=repo["url"]
    e["RESTIC_PASSWORD"]=repo["key"]
    data = get_command(f"restic snapshots --json", env=e)
    return json.loads(data)


# Define the path to the JSON file
STATUS_FILE = "{{ homedir }}/status.json"

def get_status(name):
    if not os.path.exists(STATUS_FILE):
        return False
    with open(STATUS_FILE, 'r') as file:
        try:
            statuses = json.load(file)
        except json.JSONDecodeError:
            return False  # Return False if the file is empty or corrupted
    return statuses.get(name, False)

def set_status(name, value):
    statuses = {}
    if os.path.exists(STATUS_FILE):
        with open(STATUS_FILE, 'r') as file:
            try:
                statuses = json.load(file)
            except json.JSONDecodeError:
                pass  # Ignore errors and start with an empty dictionary
    statuses[name] = value
    with open(STATUS_FILE, 'w') as file:
        json.dump(statuses, file, indent=4)


# Check that we can open the repositories properly
repos_in_error=[]
repos_ok=[]
polynomial=""
polynomial_ok=True
for r in repos:
    print(f"Checking repo {r['name']}")
    output,error,rc = get_command("restic cat config --json",{"RESTIC_REPOSITORY": r['url'],"RESTIC_PASSWORD": r['key'] }, full_return=True)
    if rc!=0:
        repos_in_error.append(r)
    else:
        repoconfig=json.loads(output)
        if polynomial=="":
            polynomial=repoconfig["chunker_polynomial"]
        else:
            if polynomial!=repoconfig["chunker_polynomial"]:
                polynomial_ok=False
        repos_ok.append({"repo":r,"config":repoconfig})

if len(repos_ok)==0:
    print("None of the repositories can be accessed.  At least one must be reachable for me to output repository init commands")
    sys.exit(1)

if polynomial_ok==False:
    print("Not all repositories have the same chunker polynomial configured.  This can ONLY be configured when the repository is first created.  Please delete the repositories you can rebuild...")
    for r in repos_ok:
        print(f"Repo: {r['repo']['url']} polynomial: {r['config']['chunker_polynomial']}")
    sys.exit(1)

if len(repos_in_error)!=0:
    print("Could not open all repositories.  Check that they are accessible and that the passwords are correct.  If they are not yet initialized, use the following commands:")
    repo_from=repos_ok[0]['repo']
    for r in repos_in_error:
        print()
        print(f"RESTIC_PASSWORD={r['key']} RESTIC_FROM_PASSWORD={repo_from['key']} restic init --copy-chunker-params=true --from-repo {repo_from['url']} -r {r['url']}")
    sys.exit(1)


for r in repos:
    print(f"Getting snapshot list for repo {r['name']}")
    r['snapshots'] = get_snapshot_info(r)

# Verify that we have the correct backups stored
allhosts = set()
hostsok = True
for r in repos:
    wronghosts = set()
    allhosts.update(r['hosts'])
    for s in r['snapshots']:
        if s['hostname'] not in r['hosts']:
            wronghosts.update(s['hostname'])
    if wronghosts:
        print(f"The repository {r['name']} contains backups for unknown hosts {wronghosts}, either delete the backups, or add the hosts to the list")
        hostsok = False
if not hostsok:
    print("Host information not ok, aborting")
    sys.exit(1)

for host in allhosts:
    print(f"Syncing hostname {host}")
    most_recent_backup_ts = 0
    most_recent_backup_str = ""
    most_recent_backup_on = {}
    most_recent_backup_id = ""
    for r in repos:
        for s in r['snapshots']:
            if s['hostname']!=host:
                continue
            time_string = s["time"]
            # Python does not accept a : in the timezone, yet go's code places it.  Fix this...
            # time_string = time_string[:-6] + time_string[-6:].replace(":","")
            # Python only accepts 6 digits in the fractals for the seconds....
            frac_seconds_str = time_string.split('.')[-1].rstrip('Z')
            frac_seconds_len = len(frac_seconds_str)
            # Truncate or pad the fractional seconds string as needed
            if frac_seconds_len >= 4:
                frac_seconds_str = frac_seconds_str[:4]
            time_string = time_string[:-frac_seconds_len] + frac_seconds_str + 'Z'
            unix_time = datetime.datetime.strptime(time_string, "%Y-%m-%dT%H:%M:%S.%f%z").timestamp()

            if unix_time>most_recent_backup_ts:
                most_recent_backup_ts = unix_time
                most_recent_backup_str = s["time"]
                most_recent_backup_on = r
                most_recent_backup_id = s['id']
    if most_recent_backup_ts == 0:
        print(f"WARNING: There are no backups for {host}")
        continue

    # We now know the most recent backup.  See if a backup is present on all targets that carry this hostname.
    have_a_copy=False
    for r in repos:
        if host not in r['hosts']:
            continue
        if r['url']==most_recent_backup_on['url']:
            continue
        have_a_copy = True
        copy_exists = False
        for s in r['snapshots']:
            if s['time']==most_recent_backup_str:
                copy_exists = True
        if copy_exists:
            continue

        # Copy!
        print(f"Copying backup {most_recent_backup_id} from {most_recent_backup_on['name']} to {r['name']}")
        e = {}
        e["RESTIC_REPOSITORY"]=r["url"]
        e["RESTIC_PASSWORD"]=r["key"]
        e["RESTIC_FROM_REPOSITORY"]=most_recent_backup_on["url"]
        e["RESTIC_FROM_PASSWORD"]=most_recent_backup_on["key"]
        run_command(f"restic copy {most_recent_backup_id}", env=e)

    idle = False
    timeout = 10
    if host in hosts:
        idle = hosts[host]["idle"]
        timeout = hosts[host]["timeout"]
    if not idle:
        if not have_a_copy:
            print(f"WARNING: We do not have a copy for {host}")
        if most_recent_backup_ts < time.time()-(timeout*24*3600):
            print(f"WARNING: Last backup for {host} is too old")

for r in repos:
    e = {}
    e["RESTIC_REPOSITORY"]=r["url"]
    e["RESTIC_PASSWORD"]=r["key"]

    name = "repo_check_" + r["name"]
    name2 = "repo_check_ok_" + r["name"]
   
    if r["check_repo"]:
        current_time = int(time.time())  # Get the current Unix timestamp
        last_execution_time = get_status(name)

        # only check once every 12h.  If it is ok, we check 5%, so on average it takes 20 days
        # to read the entire repo if we are extreamly lucky with the random.  But scanning 100%
        # is very expensive, so we don't do it, unless we are not sure it is all ok.
        # So always scan 100% unless we know it is ok already from a previous scan.
        # if a scan fails, we reset the ok flag before scanning, so next time it will be back 100%
        if last_execution_time is False or (current_time - last_execution_time) > (12 * 60 * 60):
            repo_ok = get_status(name2)
            set_status(name2, False)
            if repo_ok:
                print(f"Checking random part of the backups for repo {r['name']}....")
                run_command(f"restic check --read-data-subset=5%", env=e)
            else:
                print(f"Checking full backup of the backups for repo {r['name']}....")
                run_command("restic check", env=e)
            set_status(name2, True)
            set_status(name, current_time)

for r in repos:
    e = {}
    e["RESTIC_REPOSITORY"]=r["url"]
    e["RESTIC_PASSWORD"]=r["key"]
    name = "repo_purge_" + r["name"]
   
    current_time = int(time.time())  # Get the current Unix timestamp
    last_execution_time = get_status(name)

    if last_execution_time is False or (current_time - last_execution_time) > (15 * 24 * 60 * 60):
        print(f"forgetting old backups for repo {r['name']}....")
        run_command(f"restic forget {r['cleanup_parameters']}", env=e)

        print(f"Pruning old backups for repo {r['name']}....")
        run_command("restic prune --max-unused 10%", env=e)

        set_status(name, current_time)