#!/usr/bin/env bash
set -Eeuo pipefail

required_variables=(
    SOURCE_DIR
    DEPLOY_ROOT
    CONTAINER_DEPLOY_ROOT
    PHP_CONTAINER
    HEALTHCHECK_URL
    BACKUP_COMMAND
)

for variable_name in "${required_variables[@]}"; do
    test -n "${!variable_name:-}" || {
        printf 'ERROR: %s is required.\n' "$variable_name" >&2
        exit 1
    }
done

release_id="${RELEASE_ID:-$(date -u +%Y%m%d%H%M%S)}"
keep_releases="${KEEP_RELEASES:-5}"
php_user="${PHP_RUNTIME_USER:-1000:1000}"
php_group="${PHP_RUNTIME_GROUP:-1000}"
dry_run="${DRY_RUN:-false}"
host_release="$DEPLOY_ROOT/releases/$release_id"
container_release="$CONTAINER_DEPLOY_ROOT/releases/$release_id"
previous_release=""
maintenance_enabled=false

run() {
    if test "$dry_run" = "true"; then
        printf 'DRY-RUN:'
        printf ' %q' "$@"
        printf '\n'
        return 0
    fi
    "$@"
}

artisan() {
    run docker exec --user "$php_user" --workdir "$container_release" \
        "$PHP_CONTAINER" php artisan "$@"
}

restore_previous_release() {
    if test "$dry_run" != "true" && test -n "$previous_release"; then
        ln -s "$previous_release" "$DEPLOY_ROOT/.current.rollback"
        mv -Tf "$DEPLOY_ROOT/.current.rollback" "$DEPLOY_ROOT/current"
    fi
}

recover() {
    exit_code=$?
    if test "$exit_code" -ne 0; then
        printf 'Deployment failed; restoring the previous code release.\n' >&2
        restore_previous_release
    fi
    if test "$maintenance_enabled" = "true" && test -L "$DEPLOY_ROOT/current"; then
        docker exec --user "$php_user" \
            --workdir "$CONTAINER_DEPLOY_ROOT/current" \
            "$PHP_CONTAINER" php artisan up >/dev/null 2>&1 || true
    fi
    exit "$exit_code"
}
trap recover EXIT
trap 'exit 143' TERM
trap 'exit 130' INT

test -d "$SOURCE_DIR" || {
    printf 'ERROR: Source directory does not exist: %s\n' "$SOURCE_DIR" >&2
    exit 1
}
test -f "$DEPLOY_ROOT/shared/.env" || {
    printf 'ERROR: Shared production .env does not exist.\n' >&2
    exit 1
}
test -d "$DEPLOY_ROOT/shared/storage" || {
    printf 'ERROR: Shared storage directory does not exist.\n' >&2
    exit 1
}
command -v flock >/dev/null 2>&1 || {
    printf 'ERROR: flock is required on the production host.\n' >&2
    exit 1
}
exec 9>"$DEPLOY_ROOT/.deploy.lock"
flock -w 600 9 || {
    printf 'ERROR: Another deployment still holds the production lock.\n' >&2
    exit 1
}

if test -L "$DEPLOY_ROOT/current"; then
    previous_release="$(readlink "$DEPLOY_ROOT/current")"
    if test "$dry_run" != "true"; then
        docker exec --user "$php_user" \
            --workdir "$CONTAINER_DEPLOY_ROOT/current" \
            "$PHP_CONTAINER" php artisan down --retry=30
        maintenance_enabled=true
    fi
fi

run mkdir -p "$host_release"
run rsync -a --delete \
    --exclude='.env' \
    --exclude='node_modules' \
    --exclude='storage' \
    --exclude='vendor' \
    "$SOURCE_DIR/" "$host_release/"
run chgrp -R "$php_group" "$host_release"
run chmod -R g+rwX "$host_release"
run ln -s ../../shared/.env "$host_release/.env"
run ln -s ../../shared/storage "$host_release/storage"

run docker exec --user "$php_user" --workdir "$container_release" \
    "$PHP_CONTAINER" composer install \
    --no-dev --no-interaction --prefer-dist --optimize-autoloader

if test "$dry_run" != "true"; then
    bash -c "$BACKUP_COMMAND"
fi

artisan migrate --force
artisan storage:link
artisan optimize:clear
artisan config:cache
artisan route:cache
artisan view:cache

run ln -s "releases/$release_id" "$DEPLOY_ROOT/.current.next"
run mv -Tf "$DEPLOY_ROOT/.current.next" "$DEPLOY_ROOT/current"

if test "$dry_run" != "true"; then
    docker exec "$PHP_CONTAINER" kill -USR2 1
    docker exec --user "$php_user" \
        --workdir "$CONTAINER_DEPLOY_ROOT/current" \
        "$PHP_CONTAINER" php artisan up
    maintenance_enabled=false
    curl --fail --silent --show-error \
        --retry 6 --retry-delay 5 --retry-connrefused \
        "$HEALTHCHECK_URL" >/dev/null

    active_target="$(readlink "$DEPLOY_ROOT/current")"
    mapfile -t old_releases < <(
        ls -1dt "$DEPLOY_ROOT"/releases/* 2>/dev/null |
            awk -v keep="$keep_releases" -v active="$DEPLOY_ROOT/$active_target" '
                $0 != active { seen++; if (seen >= keep) print }
            '
    )
    if test "${#old_releases[@]}" -gt 0; then
        rm -rf -- "${old_releases[@]}"
    fi
fi

trap - EXIT
printf 'Deployment succeeded: %s\n' "$release_id"