#!/bin/bash -e

# The default values have been selected trying to match with most of
# the wait times in the tests and also trying to follow common sense.
DEFAULT_WAIT_FOR_SSH_ATTEMPTS=800
DEFAULT_WAIT_FOR_SSH_WAIT=1
DEFAULT_WAIT_FOR_NO_SSH_ATTEMPTS=200
DEFAULT_WAIT_FOR_NO_SSH_WAIT=1
DEFAULT_WAIT_FOR_SNAP_COMMAND_ATTEMPTS=200
DEFAULT_WAIT_FOR_SNAP_COMMAND_WAIT=1
DEFAULT_WAIT_FOR_DEV_INIT_ATTEMPTS=60
DEFAULT_WAIT_FOR_DEV_INIT_WAIT=1
DEFAULT_WAIT_FOR_REBOOT_ATTEMPTS=120
DEFAULT_WAIT_FOR_REBOOT_WAIT=5

show_help() {
    echo "usage: remote.wait-for ssh [--wait WAIT] [-n|--attempts ATTEMPTS]"
    echo "       remote.wait-for no-ssh  [--wait WAIT] [-n|--attempts ATTEMPTS]"
    echo "       remote.wait-for snap-command [--wait WAIT] [-n|--attempts ATTEMPTS]"
    echo "       remote.wait-for reboot [--wait WAIT] [-n|--attempts ATTEMPTS]"
    echo "       remote.wait-for device-initialized [--wait WAIT] [-n|--attempts ATTEMPTS]"
    echo "       remote.wait-for refresh [--wait WAIT] [-n|--attempts ATTEMPTS]"
    echo ""
    echo "Available options:"
    echo "  -h --help   show this help message."
    echo ""
}

wait_for_ssh() {
    local attempts=${1:-$DEFAULT_WAIT_FOR_SSH_ATTEMPTS}
    local wait=${2:-$DEFAULT_WAIT_FOR_SSH_WAIT}
    echo "remote.wait-for: waiting for ssh connection"

    until remote.exec "true" &>/dev/null; do
        echo -n '.'
        attempts=$(( attempts - 1 ))
        if [ $attempts -le 0 ]; then
            echo ""
            echo "remote.wait-for: timed out waiting for ssh connection to succeed"
            return 1
        fi
        sleep "$wait"
    done
    echo ""
    echo "remote.wait-for: ssh connection established"
}

wait_for_no_ssh() {
    local attempts=${1:-$DEFAULT_WAIT_FOR_NO_SSH_ATTEMPTS}
    local wait=${2:-$DEFAULT_WAIT_FOR_NO_SSH_WAIT}

    echo "remote.wait-for: waiting for no ssh connection"

    while remote.exec "true" &>/dev/null; do
        echo -n '.'
        attempts=$(( attempts - 1 ))
        if [ $attempts -le 0 ]; then
            echo ""
            echo "remote.wait-for: timed out waiting for ssh connection to fail"
            return 1
        fi
        sleep "$wait"
    done
    echo ""
    echo "remote.wait-for: ssh connection lost"
}


wait_for_snap_command() {
    local attempts=${1:-$DEFAULT_WAIT_FOR_SNAP_COMMAND_ATTEMPTS}
    local wait=${2:-$DEFAULT_WAIT_FOR_SNAP_COMMAND_WAIT}

    echo "remote.wait-for: waiting for snap command"

    while ! remote.exec "command -v snap" &>/dev/null; do
        echo -n '.'
        attempts=$(( attempts - 1 ))
        if [ $attempts -le 0 ]; then
            echo ""
            echo "remote.wait-for: timed out waiting for snap command to succeed"
            return 1
        fi
        sleep "$wait"
    done
    echo ""
    echo "remote.wait-for: snap command ready"   
}

get_boot_id() {
    remote.exec "cat /proc/sys/kernel/random/boot_id"
}

wait_for_reconnect_ssh() {
    echo "remote.wait-for: waiting for ssh to reconnect"
    wait_for_no_ssh "$DEFAULT_WAIT_FOR_NO_SSH_ATTEMPTS" "$DEFAULT_WAIT_FOR_NO_SSH_WAIT"
    wait_for_ssh "$DEFAULT_WAIT_FOR_SSH_ATTEMPTS" "$DEFAULT_WAIT_FOR_SSH_WAIT"
}

wait_for_reboot() {
    local attempts=${1:-$DEFAULT_WAIT_FOR_REBOOT_ATTEMPTS}
    local wait=${2:-$DEFAULT_WAIT_FOR_REBOOT_WAIT}
    local initial_boot_id=$3
    local last_boot_id

    echo "remote.wait-for: waiting for reboot"

    if [ -z "$initial_boot_id" ]; then
        echo "remote.wait-for: initial boot id not set"
        wait_for_reconnect_ssh
        return
    fi

    while [ "$attempts" -ge 0 ]; do
        echo -n '.'
        attempts=$(( attempts - 1 ))
        # The get_boot_id could fail because the connection is broken due to the reboot
        last_boot_id="$(get_boot_id)" || true
        # The boot_id is a GUID, i.e. 450d12a1-9811-464e-8c9e-cec1c60e8684
        if [[ "$last_boot_id" =~ .*-.*-.*-.*-.* ]] && [ "$last_boot_id" != "$initial_boot_id" ]; then
            break
        fi
        sleep "$wait"
    done

    echo ""
    if [ "$last_boot_id" != "$initial_boot_id" ]; then
        echo "remote.wait-for: reboot completed"
    else
        echo "remote.wait-for: boot id did not change"
        return 1
    fi

}

wait_for_device_initialized() {
    local attempts=${1:-$DEFAULT_WAIT_FOR_DEV_INIT_ATTEMPTS}
    local wait=${2:-$DEFAULT_WAIT_FOR_DEV_INIT_WAIT}

    echo "remote.wait-for: waiting for device initialized"

    while ! remote.exec "snap changes" | grep -Eq "Done.*Initialize device"; do
        echo -n '.'
        attempts=$(( attempts - 1 ))
        if [ $attempts -le 0 ]; then
            echo ""
            echo "remote.wait-for: timed out waiting for device to be fully initialized. Aborting!"
            return 1
        fi
        sleep "$wait"
    done
    echo ""
    echo "remote.wait-for: device initialized"
}

wait_for_refresh_reboot() {
    echo "remote.wait-for: waiting for refresh reboot"

    local change_id=${1:-}
    local boot_id=${2:-}
    if [ -z "$change_id" ] || [ -z "$boot_id" ]; then
        echo "remote.wait-for: either change_id or boot_id not provided"
        return 1
    fi

    wait_for_ssh "$DEFAULT_WAIT_FOR_SSH_ATTEMPTS" "$DEFAULT_WAIT_FOR_SSH_WAIT"
    for _ in $(seq 5); do
        # The refresh is being executed
        # It checks a that refresh is in state either Do or Doing (and not Done)
        if remote.exec "snap changes" | grep -Eq "$change_id.*( Do | Doing ).*(Auto-refresh|Refresh)"; then
            # The systems is waiting for reboot
            if remote.exec "sudo journalctl -u snapd -n 30" | grep -q "Waiting for system reboot"; then
                echo "remote.wait-for: waiting for system reboot"
                remote.exec "sudo reboot" || true
                wait_for_no_ssh "$DEFAULT_WAIT_FOR_NO_SSH_ATTEMPTS" "$DEFAULT_WAIT_FOR_NO_SSH_WAIT"
                break
            fi
            echo "remote.wait-for: either auto-refresh or refresh in progress"
        fi

        # when the refresh has finished and no reboot needed, the function returns
        if remote.exec "snap changes" | grep -Eq "$change_id.*Done.*(Auto-refresh|Refresh)"; then
            echo "remote.wait-for: refresh completed, reboot not required"
            return
        fi

        if remote.exec "snap changes" | grep -Eq "$change_id.*Error.*(Auto-refresh|Refresh)"; then
            echo "remote.wait-for: refresh finished with error"
            return 1
        fi

        echo "remote.wait-for: system reboot not detected"
        sleep 1
    done
    wait_for_ssh "$DEFAULT_WAIT_FOR_SSH_ATTEMPTS" "$DEFAULT_WAIT_FOR_SSH_WAIT"
    if [ "$(remote.exec "cat /proc/sys/kernel/random/boot_id")" == "$boot_id" ]; then
        echo "remote.wait-for: boot id did not change"
        return 1
    else
        echo "remote.wait-for: boot id changed, refresh completed with reboot"
    fi
}

wait_for_refresh(){
    echo "remote.wait-for: waiting for either auto-refresh or refresh"

    # It checks a that refresh is in state either Do or Doing (and not Done)
    change_line="$(remote.exec 'snap changes' | grep -E '( Do | Doing ).*(Auto-refresh|Refresh)' || true)"
    if [ -n "$change_line" ]; then
        echo "remote.wait-for: refresh in progress"
        change_id="$(echo "$change_line" | awk '{ print $1 }')"
        boot_id="$(remote.exec "cat /proc/sys/kernel/random/boot_id")"

        for _ in $(seq 20); do
            if wait_for_refresh_reboot "$change_id" "$boot_id"; then
                break
            fi
        done
        echo ""

        changes="$(remote.exec 'snap changes')"
        # It checks a that refresh is in state either Do or Doing (and not Done)
        if echo "$changes" | grep -Eq "$change_id.*( Do | Doing ).*(Auto-refresh|Refresh)"; then
            echo "remote.wait-for: still doing refresh, exiting"
        elif echo "$changes" | grep -Eq "$change_id.*Error.*(Auto-refresh|Refresh)"; then
            echo "remote.wait-for: refresh failed"
        elif echo "$changes" | grep -Eq "$change_id.*Done.*(Auto-refresh|Refresh)"; then
            echo "remote.wait-for: refresh completed"
        else
            echo "remote.wait-for: refresh results unknown"
            echo "$changes"
            return 1
        fi
    else
        echo "remote.wait-for: no refresh in progress"
    fi
}

main() {
    if [ $# -eq 0 ]; then
        show_help
        exit
    fi

    local action wait attempts others
    case "$1" in
        -h|--help)
            show_help
            exit
            ;;
        ssh)
            action=wait_for_ssh
            shift
            ;;
        no-ssh)
            action=wait_for_no_ssh
            shift
            ;;
        snap-command)
            action=wait_for_snap_command
            shift
            ;;
        reboot)
            action=wait_for_reboot
            shift
            ;;
        device-initialized)
            action=wait_for_device_initialized
            shift
            ;;
        refresh)
            action=wait_for_refresh
            shift
            ;;
        *)
            echo "remote.wait-for: unsupported parameter $1" >&2
            exit 1
            ;;
    esac

    if [ -z "$(declare -f "$action")" ]; then
        echo "remote.wait-for: no such command: $action"
        show_help
        exit 1
    fi

    while [ $# -gt 0 ]; do
        case "$1" in
            --wait)
                wait=$2
                shift 2
                ;;
            --attempts|-n)
                attempts=$2
                shift 2
                ;;
            *)
                if [ -z "$others" ]; then
                    others=$1
                else
                    others="$others $1"
                fi
                shift
                ;;
        esac
    done

    "$action" "$attempts" "$wait" "$others"
}

main "$@"