#!/usr/bin/env bash
# deploy.sh — prepare a deployment directory for the current repository.
#
# Designed to be copied verbatim into other Gitea-hosted service repos on this
# machine. Repo-specific values (service name, image path, project id) are
# discovered from the `origin` remote and the Gitea API, so the only thing
# baked into the convention is the host-port formula:
#
#   host_port = 5000 + 10 * <gitea_project_id> + <service_number>
#
# Usage:
#   deploy/deploy.sh <version> [service_number]
#
# Output:
#   <DEPLOY_ROOT>/<repo>-<service_number>/docker-compose.yml
#   <DEPLOY_ROOT>/<repo>-<service_number>/.deploy.meta
#   <DEPLOY_ROOT>/<repo>-<service_number>/.env       (copied from .env.example
#                                                     on first run if absent)
#
# Environment overrides:
#   DEPLOY_ROOT         base directory (default: $HOME/deployments)
#   TEMPLATE            path to compose template (default:
#                       <repo>/deploy/docker-compose.template.yml)
#   GITEA_BASE_URL      e.g. http://192.168.33.22:3300
#                       (default: http://<remote-host>:3300)
#   GITEA_API_BASE      full API base (default: $GITEA_BASE_URL/api/v1)
#   GITEA_TOKEN         token for private repos (optional)
#   GITEA_PROJECT_ID    skip API discovery and use this id
#   REGISTRY            container registry host[:port]
#                       (default: <remote-host>:3300)
#   IMAGE_REPO          full image path host[:port]/owner/repo
#                       (default: $REGISTRY/<owner>/<repo>)
#   INCLUDE_PATHS_FILE  newline-delimited repo-relative paths to copy into the
#                       deployment dir (default: <repo>/deploy/include-paths.txt)

set -euo pipefail

die() { printf 'deploy: %s\n' "$*" >&2; exit 1; }

usage() {
  sed -n '2,/^set -euo pipefail$/p' "$0" \
    | sed '$d' \
    | sed 's/^# \{0,1\}//'
  exit 1
}

[ "$#" -ge 1 ] || usage
case "$1" in -h|--help|help) usage;; esac

VERSION="$1"
SERVICE_NUMBER="${2:-0}"

case "$SERVICE_NUMBER" in
  ''|*[!0-9]*) die "service_number must be a non-negative integer: $SERVICE_NUMBER";;
esac
case "$VERSION" in
  ''|*[[:space:]]*) die "version must be non-empty and contain no whitespace";;
esac

SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]:-$0}")" && pwd)"
REPO_DIR="$(git -C "$SCRIPT_DIR" rev-parse --show-toplevel)" \
  || die "must be run from inside a git working tree"
TEMPLATE="${TEMPLATE:-$REPO_DIR/deploy/docker-compose.template.yml}"
DEPLOY_ROOT="${DEPLOY_ROOT:-$HOME/deployments}"
INCLUDE_PATHS_FILE="${INCLUDE_PATHS_FILE:-$REPO_DIR/deploy/include-paths.txt}"

[ -r "$TEMPLATE" ] || die "template not found: $TEMPLATE"

remote_url="$(git -C "$REPO_DIR" remote get-url origin)" \
  || die "no 'origin' remote configured"

REMOTE_HOST=""; REMOTE_OWNER=""; REMOTE_REPO=""
parse_remote() {
  local url="$1" rest host_part path_part
  url="${url%.git}"
  case "$url" in
    ssh://*)
      rest="${url#ssh://}"
      rest="${rest#*@}"
      host_part="${rest%%/*}"
      path_part="${rest#*/}"
      REMOTE_HOST="${host_part%%:*}"
      ;;
    http://*|https://*)
      rest="${url#*://}"
      host_part="${rest%%/*}"
      path_part="${rest#*/}"
      REMOTE_HOST="${host_part%%:*}"
      ;;
    *@*:*)
      rest="${url#*@}"
      REMOTE_HOST="${rest%%:*}"
      path_part="${rest#*:}"
      ;;
    *)
      die "cannot parse git remote URL: $url"
      ;;
  esac
  REMOTE_OWNER="${path_part%/*}"
  REMOTE_REPO="${path_part##*/}"
  [ -n "$REMOTE_HOST" ] && [ -n "$REMOTE_OWNER" ] && [ -n "$REMOTE_REPO" ] \
    || die "could not extract host/owner/repo from: $url"
}
parse_remote "$remote_url"

GITEA_BASE_URL="${GITEA_BASE_URL:-http://${REMOTE_HOST}:3300}"
GITEA_API_BASE="${GITEA_API_BASE:-$GITEA_BASE_URL/api/v1}"
REGISTRY="${REGISTRY:-${REMOTE_HOST}:3300}"
IMAGE_REPO="${IMAGE_REPO:-${REGISTRY}/${REMOTE_OWNER}/${REMOTE_REPO}}"

if [ -z "${GITEA_PROJECT_ID:-}" ]; then
  api_url="${GITEA_API_BASE}/repos/${REMOTE_OWNER}/${REMOTE_REPO}"
  printf 'deploy: looking up project id at %s\n' "$api_url" >&2
  curl_args=(-fsS --max-time 10)
  if [ -n "${GITEA_TOKEN:-}" ]; then
    curl_args+=(-H "Authorization: token ${GITEA_TOKEN}")
  fi
  if ! resp="$(curl "${curl_args[@]}" "$api_url")"; then
    die "Gitea API call failed: $api_url
  set GITEA_PROJECT_ID=<n> to bypass discovery, or
  set GITEA_API_BASE / GITEA_TOKEN to override defaults."
  fi
  GITEA_PROJECT_ID="$(printf '%s' "$resp" | python3 -c 'import json,sys; print(json.load(sys.stdin)["id"])')" \
    || die "could not extract repo id from Gitea response"
fi

case "$GITEA_PROJECT_ID" in
  ''|*[!0-9]*) die "GITEA_PROJECT_ID is not a non-negative integer: $GITEA_PROJECT_ID";;
esac

HOST_PORT=$(( 5000 + 10 * GITEA_PROJECT_ID + SERVICE_NUMBER ))

deploy_dir="$DEPLOY_ROOT/${REMOTE_REPO}-${SERVICE_NUMBER}"
mkdir -p "$deploy_dir"

out_file="$deploy_dir/docker-compose.yml"

if [ -r "$INCLUDE_PATHS_FILE" ]; then
  while IFS= read -r include_path || [ -n "$include_path" ]; do
    include_path="${include_path%%#*}"
    include_path="$(printf '%s' "$include_path" | sed 's/^[[:space:]]*//; s/[[:space:]]*$//')"
    [ -n "$include_path" ] || continue
    src_path="$REPO_DIR/$include_path"
    dst_path="$deploy_dir/$include_path"
    [ -e "$src_path" ] || die "include path listed but missing: $include_path"
    mkdir -p "$(dirname "$dst_path")"
    rm -rf "$dst_path"
    cp -R "$src_path" "$dst_path"
  done < "$INCLUDE_PATHS_FILE"
fi

awk \
  -v image="$IMAGE_REPO" \
  -v tag="$VERSION" \
  -v host_port="$HOST_PORT" \
  -v service="$REMOTE_REPO" \
  -v service_num="$SERVICE_NUMBER" \
  -v project_id="$GITEA_PROJECT_ID" \
  '{
    gsub(/__IMAGE_TAG__/, tag);
    gsub(/__IMAGE__/, image);
    gsub(/__HOST_PORT__/, host_port);
    gsub(/__SERVICE_NAME__/, service);
    gsub(/__SERVICE_NUMBER__/, service_num);
    gsub(/__GITEA_PROJECT_ID__/, project_id);
    print;
  }' "$TEMPLATE" > "$out_file"

# Sanity check: the template authors might leave unresolved tokens by mistake.
if grep -q '__[A-Z_]\+__' "$out_file"; then
  printf 'deploy: WARNING: unresolved __TOKEN__ placeholders remain in %s\n' \
    "$out_file" >&2
fi

env_example="$REPO_DIR/.env.example"
if [ ! -e "$deploy_dir/.env" ] && [ -r "$env_example" ]; then
  cp "$env_example" "$deploy_dir/.env"
  env_seeded=1
else
  env_seeded=0
fi

cat > "$deploy_dir/.deploy.meta" <<EOF
service=$REMOTE_REPO
service_number=$SERVICE_NUMBER
version=$VERSION
image=$IMAGE_REPO:$VERSION
host_port=$HOST_PORT
gitea_project_id=$GITEA_PROJECT_ID
gitea_owner=$REMOTE_OWNER
gitea_host=$REMOTE_HOST
include_paths_file=$(basename "$INCLUDE_PATHS_FILE")
generated_at=$(date -u +%Y-%m-%dT%H:%M:%SZ)
EOF

cat <<EOF
deploy: prepared $deploy_dir
  service:    $REMOTE_REPO (#${SERVICE_NUMBER})
  image:      $IMAGE_REPO:$VERSION
  host port:  $HOST_PORT  (5000 + 10*${GITEA_PROJECT_ID} + ${SERVICE_NUMBER})
EOF

if [ "$env_seeded" = 1 ]; then
  printf 'deploy: seeded .env from .env.example — EDIT IT before starting\n'
fi

cat <<EOF

Next steps:
  cd "$deploy_dir"
  \$EDITOR .env
  docker compose pull
  docker compose up -d
EOF