#!/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

git fetch origin main
remote_revision="$(git rev-parse FETCH_HEAD)"
current_revision="$(git rev-parse HEAD)"
deployed_revision=""
if [[ -f "$deployed_revision_file" ]]; then
    read -r deployed_revision <"$deployed_revision_file"
fi

container="$("${compose[@]}" ps -q yawn 2>/dev/null || true)"
container_status="missing"
if [[ -n "$container" ]]; then
    container_status="$(docker inspect --format '{{if .State.Health}}{{.State.Health.Status}}{{else}}{{.State.Status}}{{end}}' "$container" 2>/dev/null || true)"
fi

if [[ "$current_revision" == "$remote_revision" &&
    "$deployed_revision" == "$remote_revision" &&
    "$container_status" == "healthy" ]]; then
    printf 'Yawn is already running revision %s.\n' "${remote_revision:0:12}"
    exit 0
fi

printf 'Deploying revision %s...\n' "${remote_revision:0:12}"
flock -u 9
exec 9>&-
"$repository/server/deploy-docker.sh"