#!/bin/bash

set -eu

info()    { echo "[INFO]    $*"; }
warning() { echo "[WARNING] $*"; }
error()   { echo "[ERROR]   $*"; }
fatal()   { echo "[FATAL]   $*"; exit 1; }

# Config
#
# Presets are available, and can be used with the env var "TARGET_NAME":
# - TARGET_NAME=www.cof for www.cof.ens.fr
# - TARGET_NAME=dev.cof for dev.cof.ens.fr

TARGET_NAME="${TARGET_NAME:-dev.cof}"

SERVICE_DIR="${SERVICE_DIR:-/etc/system/systemd}"

if [ "${TARGET_NAME}" = "www.cof" ]; then
    DJANGO_SETTINGS_MODULE="cof.settings.prod"
    SERVICE_DAPHNE_PATH="${SERVICE_DIR}/gestiocof-daphne.service"
    SERVICE_WORKER_PATH="${SERVICE_DIR}/gestiocof-worker.service"
    SERVICE_LOCAL_DIR="./provisioning/www.cof/systemd"
    VENV="<path/to/venv>"
elif [ "${TARGET_NAME}" = "dev.cof" ]; then
    DJANGO_SETTINGS_MODULE="cof.settings.<WHICH ONE?>"
    SERVICE_DAPHNE_PATH="${SERVICE_DIR}/gestiocof-dev-daphne.service"
    SERVICE_WORKER_PATH="${SERVICE_DIR}/gestiocof-dev-worker.service"
    SERVICE_LOCAL_DIR="./provisioning/dev.cof/systemd"
    VENV="<path/to/venv>"
fi

SERVICE_LOCAL_DAPHNE_PATH="${SERVICE_LOCAL_DIR}/daphne.service"
SERVICE_LOCAL_WORKER_PATH="${SERVICE_LOCAL_DIR}/worker.service"
PYTHON="DJANGO_SETTINGS_MODULE=${DJANGO_SETTINGS_MODULE} ${VENV}/bin/python"

# Default to @{u}, equivalent to "origin/<current branch>".
GIT_TARGET="${GIT_TARGET:-@{u}}"

# Services

service_print_changes() {
    # TODO: One could check diff, print it and prompt user to confirm.
    # info ">>> Services: diff"
    return
}

service_start() {
    info "Starting service ${1}..."
    sudo systemctl enable "${2}"
    sudo systemctl start "${2}"
}

service_stop() {
    info "Stopping service ${1}... "
    if sudo systemctl stop "${2}"; then info OK; else warning SKIPPED; fi
}

service_upgrade_config() {
    info "Upgrading config of service ${1}... "
    sudo cp "${2}" "${3}"
}

service_start_all() {
    info ">>> Services: starting all..."
    service_start Worker "${SERVICE_WORKER_PATH}"
    service_start Daphne "${SERVICE_DAPHNE_PATH}"
}

service_stop_all() {
    info ">>> Services: stopping all..."
    service_stop Worker "${SERVICE_WORKER_PATH}"
    service_stop Daphne "${SERVICE_DAPHNE_PATH}"
}

service_upgrade_config_all() {
    info ">>> Services: upgrading all..."
    service_upgrade Daphne "${SERVICE_LOCAL_DAPHNE_PATH}" "${SERVICE_DAPHNE_PATH}"
    service_upgrade Worker "${SERVICE_LOCAL_WORKER_PATH}" "${SERVICE_WORKER_PATH}"
    systemctl daemon-reload
}

# Django

django_migrate() {
    info ">>> Django: applying database migrations..."
    ${PYTHON} manage.py migrate
}

django_collectstatic() {
    info ">>> Django: collecting static assets and placing them in configured location..."
    ${PYTHON} manage.py collectstatic
}

# Git

git_check_clean_workingtree() {
    [ -z "$(git status --porcelain)" ]
}

git_run_checks() {
    info ">>> Git: running checks"

    info "- Checking working tree state... "
    if ! git_check_clean_workingtree; then
        git status -s
        warning "The working tree is not cleaned. Some data could be lost."
        warning "Stash or commit the changes."
        read -rp "Do you want to continue? [y/N] " continue
        [ "$continue" = y ] || fatal "Aborting!"
    fi

    info "- Current commit is: $(git rev-parse HEAD)"
    info "- New commit will be: ${GIT_TARGET}"
}

git_upgrade() {
    info ">>> Git: pulling latest version of remote branch"
    # git fetch
    # git reset --hard "${GIT_TARGET}"
}

# Our job

main() {
    git_run_checks
    service_stop_all
    git_upgrade
    # TODO: Handle failure of the following commands
    service_print_changes
    django_migrate
    django_collectstatic
    service_upgrade_all
    service_start_all
}

if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
    main "$@"
fi