#! /usr/bin/env bash

set -euo pipefail

#### Detect Toolkit Project Root ####
# if realpath is not available, create a semi-equivalent function
command -v realpath >/dev/null 2>&1 || realpath() {
  [[ $1 = /* ]] && echo "$1" || echo "$PWD/${1#./}"
}
SCRIPT_PATH="$(realpath "${BASH_SOURCE[0]}")"
SCRIPT_DIR="$(dirname "$SCRIPT_PATH")"
TOOLKIT_ROOT="$(realpath "$SCRIPT_DIR/..")"
if [[ ! -d "$TOOLKIT_ROOT/bin" ]] || [[ ! -d "$TOOLKIT_ROOT/config" ]]; then
  echo "ERROR: could not find root of overleaf-toolkit project (inferred project root as '$TOOLKIT_ROOT')"
  exit 1
fi

DEFAULT_TAIL_LINES=20
ALL_SERVICES=(chat clsi contacts docstore document-updater filestore git-bridge \
    mongo notifications real-time redis spelling tags track-changes web \
    history-v1 project-history)

LOGS_PID_FILE="/tmp/toolkit-logs.$$.pid"

function usage() {
    echo "Usage: bin/logs [OPTIONS] [SERVICES...]

Services:  chat, clsi, contacts, docstore, document-updater, filestore,
           git-bridge, mongo, notifications, real-time, redis, spelling,
           tags, track-changes, web, history-v1, project-history

Options:
  -f              follow log output
  -n {number}     number of lines to print (default $DEFAULT_TAIL_LINES)
                  use '-n all' to show all log lines

Examples:

    bin/logs -n 50 web clsi

    bin/logs -n all web > web.log

    bin/logs -f web

    bin/logs -f web chat docstore

    bin/logs -n 100 -f filestore

    bin/logs -f"
}

function parse_args() {
    TAIL_LINES=$DEFAULT_TAIL_LINES
    FOLLOW=false

    if [[ $# -gt 0 && $1 =~ ^help|-h|--help$ ]]; then
        usage && exit
    fi

    while getopts "fn:" opt
    do
        case $opt in
            f) FOLLOW=true ;;
            n) TAIL_LINES="$OPTARG" ;;
            \?) usage && exit 1;;
        esac
    done
    shift $(( OPTIND - 1 ))

    if [[ $# -eq 0 ]]; then
        SERVICES=("${ALL_SERVICES[@]}")
    else
        SERVICES=("$@")
    fi
}

function docker_compose() {
    # Ignore stderr and errors when calling docker compose
    "$TOOLKIT_ROOT/bin/docker-compose" "$@" 2>/dev/null || true
}

function kill_background_jobs() {
    if [[ ${#COMPOSE_LOGS_PIDS[@]} -gt 0 ]]; then
        # Kill "docker compose logs" processes
        kill "${COMPOSE_LOGS_PIDS[@]}" 2>/dev/null || true
    fi

    # Kill "tail -f" processes started inside the sharelatex container
    docker_compose exec -T sharelatex bash -c "
        [[ -f $LOGS_PID_FILE ]] && kill \$(cat $LOGS_PID_FILE) 2>/dev/null
        rm -f $LOGS_PID_FILE"
}

function show_logs() {
    COMPOSE_LOGS_PIDS=()
    trap kill_background_jobs EXIT

    for service in "${SERVICES[@]}"; do
        if [[ $service =~ ^(git-bridge|mongo|redis)$ ]]; then
            show_compose_logs "$service" &
            COMPOSE_LOGS_PIDS+=($!)
        else
            show_sharelatex_logs "$service" &
        fi
    done

    wait
}

function show_compose_logs() {
    local service="$1"
    local flags=(--no-color)

    if [[ $FOLLOW == "true" ]]; then
        flags+=(-f)
    fi
    if [[ $TAIL_LINES != "all" ]]; then
        flags+=(--tail="$TAIL_LINES")
    fi
    if [[ ${#SERVICES[@]} -eq 1 ]]; then
        # Do not add a service prefix when outputting logs from a single
        # service
        flags+=(--no-log-prefix)
    fi

    docker_compose logs "${flags[@]}" "$service"
}

function show_sharelatex_logs() {
    local service="$1"
    local log_path="/var/log/sharelatex/$service.log"
    local flags=()

    if [[ $FOLLOW == "true" ]]; then
        flags+=(-f)
    fi
    if [[ $TAIL_LINES = "all" ]]; then
        flags+=(-n "+1")
    else
        flags+=(-n "$TAIL_LINES")
    fi

    local logs_cmd="[[ -f $log_path ]] && echo \$\$ >> $LOGS_PID_FILE && tail --pid=\$\$ ${flags[*]} $log_path"
    if [[ ${#SERVICES[@]} -gt 1 ]]; then
        # Roughly reproduce the service prefix format from docker compose
        local padded_service
        padded_service=$(printf "%-13s" "$service")
        logs_cmd="$logs_cmd | sed -u -e 's/^/$padded_service | /'"
    fi

    docker_compose exec -T sharelatex bash -c "$logs_cmd"
}

parse_args "$@"
show_logs