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

repository="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.." && pwd)"
expected_repository="$HOME/yawn"
state_directory="$HOME/.local/state/yawn"
deployed_revision_file="$state_directory/deployed-revision"
compose=(docker compose --project-name yawn --project-directory "$repository" --file "$repository/compose.yaml")

if [[ "$repository" != "$expected_repository" ]]; then
    printf 'Expected the repository at %s, found %s\n' "$expected_repository" "$repository" >&2
    exit 1
fi

for command in git docker flock; do
    if ! command -v "$command" >/dev/null 2>&1; then
        printf 'Missing required command: %s\n' "$command" >&2
        exit 1
    fi
done
if ! docker compose version >/dev/null 2>&1; then
    printf 'Docker Compose v2 is required.\n' >&2
    exit 1
fi

mkdir -p "$state_directory"
exec 9>"$state_directory/deploy.lock"
if ! flock -n 9; then
    printf 'Another Yawn deployment is already running.\n'
    exit 0
fi

cd "$repository"

if [[ "$(git branch --show-current)" != "main" ]]; then
    printf 'Deployments must run from the main branch.\n' >&2
    exit 1
fi
if [[ -n "$(git status --porcelain --untracked-files=normal)" ]]; then
    printf 'Refusing to deploy a checkout with local changes.\n' >&2
    exit 1
fi

printf 'Updating main...\n'
git fetch origin main
fetched="$(git rev-parse FETCH_HEAD)"
git merge --ff-only "$fetched"
if [[ "$(git rev-parse HEAD)" != "$fetched" ]]; then
    printf 'HEAD does not match origin/main after updating.\n' >&2
    exit 1
fi

printf 'Building the production image...\n'
"${compose[@]}" build --pull yawn
"${compose[@]}" up -d --remove-orphans yawn

container="$("${compose[@]}" ps -q yawn)"
if [[ -z "$container" ]]; then
    printf 'Docker Compose did not create the Yawn container.\n' >&2
    exit 1
fi

printf 'Waiting for Yawn to become healthy...\n'
for _ in {1..60}; do
    status="$(docker inspect --format '{{if .State.Health}}{{.State.Health.Status}}{{else}}{{.State.Status}}{{end}}' "$container")"
    case "$status" in
        healthy)
            temporary_revision="$(mktemp "$state_directory/deployed-revision.XXXXXX")"
            git rev-parse HEAD >"$temporary_revision"
            mv -f -- "$temporary_revision" "$deployed_revision_file"
            printf 'The Yawn container is healthy.\n'
            exit 0
            ;;
        unhealthy | exited | dead)
            "${compose[@]}" logs --tail 50 yawn >&2
            exit 1
            ;;
    esac
    sleep 2
done

printf 'Yawn did not become healthy before the timeout.\n' >&2
"${compose[@]}" logs --tail 50 yawn >&2
exit 1