#!/usr/bin/env bash
# Maintains a rolling "latest" release whose AppImage always has the same
# download URL, for updaters that poll a static URL (e.g. Shelly) instead of
# understanding version tags:
#
#   <server>/<owner>/<repo>/releases/download/latest/WhatsThatMusic-latest-linux-x86_64.AppImage
#
# Gitea serves ETag and Last-Modified on release assets, and replacing the
# asset changes both, which is how those updaters detect a new build.
# Gitea has no GitHub-style /releases/latest/download/ redirect, hence this.
#
# Marked as a pre-release so Gitea's own "latest release" stays the newest vX.Y.Z.
#
# Required env: TOKEN, API (…/api/v1/repos/<owner>/<repo>), GITHUB_REF_NAME, GITHUB_SHA
# Optional env: ARTIFACTS_DIR (default: artifacts)
set -euo pipefail

: "${TOKEN:?TOKEN is required}" "${API:?API is required}"
: "${GITHUB_REF_NAME:?GITHUB_REF_NAME is required}" "${GITHUB_SHA:?GITHUB_SHA is required}"
ARTIFACTS_DIR="${ARTIFACTS_DIR:-artifacts}"
LATEST_TAG="latest"
LATEST_NAME="WhatsThatMusic-latest-linux-x86_64.AppImage"

api() {
  local method="$1" path="$2"; shift 2
  local out code body
  out=$(curl -s -w '\n%{http_code}' -X "$method" -H "Authorization: token $TOKEN" "$API$path" "$@")
  code=$(printf '%s' "$out" | tail -n1)
  body=$(printf '%s' "$out" | sed '$d')
  if [ "$code" -ge 400 ]; then
    echo "$method $path -> HTTP $code" >&2
    echo "$body" >&2
    return 1
  fi
  printf '%s' "$body"
}

appimage=$(find "$ARTIFACTS_DIR" -type f -name '*.AppImage' | sort | head -n1)
if [ -z "$appimage" ]; then
  echo "No AppImage under $ARTIFACTS_DIR; cannot update the $LATEST_TAG release." >&2
  exit 1
fi

body_json=$(node -e '
  console.log(JSON.stringify({
    body: "Rolling pointer to the newest AppImage, currently " + process.argv[1] + ". " +
          "The download URL for this asset never changes; versioned downloads are on each vX.Y.Z release.",
  }));' "$GITHUB_REF_NAME")

rolling_id=$(api GET "/releases/tags/$LATEST_TAG" 2>/dev/null \
  | node -pe "JSON.parse(require('fs').readFileSync(0,'utf8')).id" 2>/dev/null || true)

if [ -z "${rolling_id:-}" ]; then
  echo "No '$LATEST_TAG' release yet; creating it."
  create_json=$(node -e '
    console.log(JSON.stringify({
      tag_name: "latest", name: "Latest (rolling)", target_commitish: process.argv[1],
      prerelease: true, body: JSON.parse(process.argv[2]).body,
    }));' "$GITHUB_SHA" "$body_json")
  rolling_id=$(api POST "/releases" -H "Content-Type: application/json" -d "$create_json" \
    | node -pe "JSON.parse(require('fs').readFileSync(0,'utf8')).id")
else
  api PATCH "/releases/$rolling_id" -H "Content-Type: application/json" -d "$body_json" >/dev/null
fi

# Replace the asset: the new upload gets a new ETag and Last-Modified.
old_id=$(api GET "/releases/$rolling_id/assets" \
  | node -pe "((JSON.parse(require('fs').readFileSync(0,'utf8'))).find(a => a.name === process.argv[1]) || {}).id || ''" "$LATEST_NAME")
if [ -n "$old_id" ]; then
  api DELETE "/releases/$rolling_id/assets/$old_id" >/dev/null
fi

echo "Uploading $LATEST_NAME from $(basename "$appimage") ($(du -h "$appimage" | cut -f1))"
api POST "/releases/$rolling_id/assets?name=$LATEST_NAME" -F "attachment=@$appimage" >/dev/null
echo "Updated '$LATEST_TAG' release ($rolling_id) to $GITHUB_REF_NAME"