#!/bin/bash

# Create a dedicated systemd config
#
# usage: ynh_add_systemd_config [--service=service] [--template=template]
# | arg: -s, --service=     - Service name (optionnal, `$app` by default)
# | arg: -t, --template=    - Name of template file (optionnal, this is 'systemd' by default, meaning `../conf/systemd.service` will be used as template)
#
# This will use the template `../conf/<templatename>.service`.
#
# See the documentation of `ynh_add_config` for a description of the template
# format and how placeholders are replaced with actual variables.
#
# Requires YunoHost version 4.1.0 or higher.

ynh::systemd::add_service() {
    local service="$app"
    local template=systemd.service
    arguments::parse \
        "-s|--service)service;String" \
        "-t|--template)template;String" \
        -- "$@"

    ynh::config::add --template="$template" --destination="/etc/systemd/system/$service.service"
    systemctl daemon-reload
    systemctl enable "$service" --quiet
}

# Remove the dedicated systemd config
#
# usage: ynh_remove_systemd_config [--service=service]
# | arg: -s, --service=     - Service name (optionnal, $app by default)
#
# Requires YunoHost version 2.7.2 or higher.
ynh::systemd::remove_service() {
    local service="$app"
    arguments::parse \
        "-s|--service)service;String" \
        -- "$@"

    local service_file="/etc/systemd/system/$service.service"
    if [ -e "$service_file" ]; then
        ynh_systemd_action --service="$service" --action=stop
        systemctl disable "$service" --quiet
        ynh::fs::remove --file="$service_file"
        systemctl daemon-reload
    fi
}

# Start (or other actions) a service,  print a log in case of failure and optionnaly wait until the service is completely started
#
# usage: ynh_systemd_action [--service_name=service_name] [--action=action] [ [--line_match="line to match"] [--log_path=log_path] [--timeout=300] [--length=20] ]
# | arg: -n, --service_name= - Name of the service to start. Default : `$app`
# | arg: -a, --action=       - Action to perform with systemctl. Default: start
# | arg: -l, --line_match=   - Line to match - The line to find in the log to attest the service have finished to boot. If not defined it don't wait until the service is completely started.
# | arg: -p, --log_path=     - Log file - Path to the log file. Default : `/var/log/$app/$app.log`
# | arg: -t, --timeout=      - Timeout - The maximum time to wait before ending the watching. Default : 300 seconds.
# | arg: -e, --length=       - Length of the error log displayed for debugging : Default : 20
#
# Requires YunoHost version 3.5.0 or higher.
ynh::systemd::action() {
    local service="$app"
    local action
    local line_match
    local log_path="/var/log/$app/$app.log"
    local timeout=300
    local length=20
    arguments::parse \
        "-s|--service)service;String" \
        "-a|--action)action;String,R" \
        "-m|--line_match)line_match;String" \
        "-p|--log_path)log_path;String" \
        "-t|--timeout)timeout;String" \
        "-l|--length)length;String" \


    # Manage case of service already stopped
    if [ "$action" == "stop" ] && ! systemctl is-active --quiet "$service"; then
        return 0
    fi

    # Start to read the log
    if ! string::empty "$line_match"; then
        local templog
        templog="$(mktemp)"
        cleanup::add "Systemd action log file" "rm -f \"$templog\""
        # Following the starting of the app in its log
        if [ "$log_path" == "systemd" ]; then
            # Read the systemd journal
            journalctl --unit="$service" --follow --since=-0 --quiet >"$templog" &
            local pid_tail=$!
        else
            # Read the specified log file
            tail --follow=name --retry --lines=0 "$log_path" >"$templog" 2>&1 &
            local pid_tail=$!
        fi
        cleanup::add "Systemd action log process" "kill -SIGTERM $pid_tail"
    fi

    # Use reload-or-restart instead of reload. So it wouldn't fail if the service isn't running.
    if [ "$action" == "reload" ]; then
        action="reload-or-restart"
    fi

    local time_start
    time_start="$(date --utc --rfc-3339=seconds | cut -d+ -f1) UTC"

    # If the service fails to perform the action
    if ! systemctl "$action" "$service"; then
        # Show syslog for this service
        run::error journalctl --quiet --no-hostname --no-pager --lines="$length" --unit="$service"
        # If a log is specified for this service, show also the content of this log
        if ! string::empty "$log_path"; then
            run::error tail --lines=$length "$log_path"
        fi
        ynh::systemd::_action_cleanup
        return 1
    fi

    if ! string::empty "$line_match"; then
        local start_time max_time long_time is_long timed_out
        start_time=$(date +%s)
        long_time=$(( start_time + 30 ))
        max_time=$(( start_time + timeout ))
        set +x
        while true; do
            # Read the log until the sentence is found, that means the app finished to start. Or run until the timeout
            if [ "$log_path" == "systemd" ]; then
                # For systemd services, we in fact dont rely on the templog, which for some reason is not reliable, but instead re-read journalctl every iteration, starting at the timestamp where we triggered the action
                if journalctl --unit="$service" --since="$time_start" --quiet --no-pager --no-hostname | grep --extended-regexp --quiet "$line_match"; then
                    log::info "The service $service has correctly executed the action $action."
                    break
                fi
            else
                if grep --extended-regexp --quiet "$line_match" "$templog"; then
                    log::info "The service $service has correctly executed the action $action."
                    break
                fi
            fi

            if string::empty "$is_long" && (( $(date +%s) >= long_time )); then
                is_long=true
                log::warn "(this may take some time)"
            fi
            if (( $(date +%s) < max_time )); then
                timed_out=true
            fi
            sleep 1
        done
        set -x

        if [[ "$timed_out" == "true" ]]; then
            log::warn "The service $service didn't fully executed the action ${action} before the timeout.\n"
            log::warn "Please find here an extract of the end of the log of the service $service:"
            run::warn journalctl --quiet --no-hostname --no-pager --lines="$length" --unit="$service"
            if [ -e "$log_path" ]; then
                log::warn --message="\-\-\-"
                run::warn tail --lines=$length "$log_path"
            fi
        fi
        ynh::systemd::_action_cleanup
    fi
}

# Clean temporary process and file used by ynh_check_starting
#
# [internal]
#
# Requires YunoHost version 3.5.0 or higher.

ynh::systemd::_action_cleanup() {
    cleanup::pop "Systemd action log process"
    cleanup::pop "Systemd action log file"
}