#!/usr/bin/env bash
#
# Write the updater manifest (`latest.json`) for one channel and attach it to that
# channel's release.
#
# WHY A SEPARATE STEP: the Linux and Windows bundles are built by two jobs in two
# workspaces, and neither can see the other's output — but ONE manifest has to
# describe both platforms. So this runs after both, reads what actually landed on
# the release, and writes the manifest from that. Building it inside either job
# would produce a manifest that silently omits the other platform, and a missing
# platform reads to a user as "no update available" rather than as a broken feed.
#
# WHAT IT READS: the release's own asset list. The signature for each bundle is a
# `.sig` asset published beside it (see publish-release.sh); its CONTENT is what
# goes in the manifest, which is why each one is downloaded rather than linked.
#
# Tauri's expected shape:
#   { "version": "0.1.0", "pub_date": "...", "notes": "...",
#     "platforms": { "<target>-<arch>": { "signature": "...", "url": "..." } } }
set -euo pipefail

: "${GITHUB_TOKEN:?GITHUB_TOKEN is required}"
: "${GITHUB_SERVER_URL:?GITHUB_SERVER_URL is required}"
: "${GITHUB_REPOSITORY:?GITHUB_REPOSITORY is required (owner/repo)}"
: "${RELEASE_TAG:?RELEASE_TAG is required (the release holding the bundles)}"
: "${APP_VERSION:?APP_VERSION is required (the version the bundles carry)}"
# The version a PERSON reads, published beside the manifest so the image build can
# describe the bundles it bakes in without re-deriving anything. Required rather
# than defaulted: a missing value here would silently publish a sidecar naming the
# wrong build, and there is nothing downstream that could catch it.
: "${DISPLAY_VERSION:?DISPLAY_VERSION is required (the human-readable version)}"

# The manifest is published to the release that HOLDS the bundles. There is no
# second place any more.
#
# There used to be: `MANIFEST_TAG` let the manifest live on a `stable` pointer
# release while the bundles sat on a versioned `v*` one, because the app can only
# read a URL that never changes and a versioned tag is not that. M314 step 3 made
# `stable` a rolling release that holds its own bundles, exactly like `dev`, so the
# split had nothing left to bridge — and a parameter that can only ever be passed
# its own default is a branch nobody exercises and a comment that goes stale.

API="$GITHUB_SERVER_URL/api/v1/repos/$GITHUB_REPOSITORY"
AUTH=(-H "Authorization: token $GITHUB_TOKEN")
NOTES="${RELEASE_NOTES:-}"

work="$(mktemp -d)"
trap 'rm -rf "$work"' EXIT INT TERM

echo "==> Reading assets on release $RELEASE_TAG"
release="$(curl -sS "${AUTH[@]}" "$API/releases/tags/$RELEASE_TAG")"
release_id="$(printf '%s' "$release" | grep -oE '"id"[[:space:]]*:[[:space:]]*[0-9]+' | head -1 | grep -oE '[0-9]+')"
[ -n "$release_id" ] || { echo "ERROR: no release tagged $RELEASE_TAG" >&2; exit 1; }
assets="$(curl -sS "${AUTH[@]}" "$API/releases/$release_id/assets")"

# Asset names, one per line. The API returns them in a single JSON blob; this is
# the only field needed, and grep beats adding a jq dependency to the CI image.
names="$(printf '%s' "$assets" | grep -oE '"name"[[:space:]]*:[[:space:]]*"[^"]+"' | sed -E 's/.*"([^"]+)"$/\1/')"

download_url() { printf '%s/%s/releases/download/%s/%s' "$GITHUB_SERVER_URL" "$GITHUB_REPOSITORY" "$RELEASE_TAG" "$1"; }

# One platform entry, or nothing if that platform's bundle or signature is absent.
# Emitting a partial entry would be worse than emitting none: the app would try to
# install something it can't verify.
platform_entry() {
  local target="$1" pattern="$2" bundle sig_name
  # Matched on THIS build's version, not just the file extension.
  #
  # The rolling dev release accumulates every build's assets, and picking the first
  # extension match returned the OLDEST one — so the manifest advertised the new
  # version while pointing at an old binary. The client would install the older
  # build, still be told the newer version was available, and update forever. The
  # signature check couldn't catch it either: the old bundle's signature is
  # perfectly valid FOR THE OLD BUNDLE.
  bundle="$(printf '%s\n' "$names" | grep -F "_${APP_VERSION}_" | grep -E "$pattern" | head -1 || true)"
  # A hard failure, not a skip: reaching here means this platform's build didn't
  # upload, and the whole point is to never advertise a bundle that isn't there.
  [ -n "$bundle" ] || { echo "    no $APP_VERSION bundle matching $pattern — skipping $target" >&2; return; }
  sig_name="$bundle.sig"
  if ! printf '%s\n' "$names" | grep -qxF "$sig_name"; then
    echo "    $bundle has no $sig_name — skipping $target (was the build signed?)" >&2
    return
  fi
  curl -fsSL "${AUTH[@]}" -o "$work/sig" "$(download_url "$sig_name")"
  # The signature is base64 on one line already; strip any stray newline so it
  # can't break the JSON string it's about to become.
  local signature
  signature="$(tr -d '\r\n' < "$work/sig")"
  printf '    "%s": { "signature": "%s", "url": "%s" }' "$target" "$signature" "$(download_url "$bundle")"
}

echo "==> Building the manifest"
entries=()
# `.AppImage` only on Linux: the updater replaces the running bundle in place, which
# a package-manager install (deb/pacman) must never have done to it.
if entry="$(platform_entry "linux-x86_64" '\.AppImage$')" && [ -n "$entry" ]; then entries+=("$entry"); fi
if entry="$(platform_entry "windows-x86_64" '\.exe$')" && [ -n "$entry" ]; then entries+=("$entry"); fi

if [ ${#entries[@]} -eq 0 ]; then
  echo "ERROR: no signed bundle on $RELEASE_TAG — refusing to publish an empty manifest." >&2
  echo "       (An empty manifest would tell every client it is up to date.)" >&2
  exit 1
fi

# No `date -u -Is` — busybox date in the CI image doesn't take it.
pub_date="$(date -u '+%Y-%m-%dT%H:%M:%SZ')"
{
  printf '{\n'
  printf '  "version": "%s",\n' "$APP_VERSION"
  printf '  "pub_date": "%s",\n' "$pub_date"
  printf '  "notes": "%s",\n' "$NOTES"
  printf '  "platforms": {\n'
  for i in "${!entries[@]}"; do
    [ "$i" -eq 0 ] || printf ',\n'
    printf '%s' "${entries[$i]}"
  done
  printf '\n  }\n'
  printf '}\n'
} > "$work/latest.json"

echo "==> Manifest:"
cat "$work/latest.json"

# Both files go on the same release the bundles were just read from — which is also
# the one `publish-release.sh` created or refreshed moments earlier, so it is
# guaranteed to exist by the time this runs.

# Replace rather than duplicate: Forgejo rejects a second asset with the same name,
# and these files are rewritten on every publish by design.
replace_asset() {
  local path="$1" name="$2" escaped old_id
  escaped="${name//./\\.}"
  old_id="$(printf '%s' "$assets" \
    | grep -oE "\"id\"[[:space:]]*:[[:space:]]*[0-9]+[^}]*\"name\"[[:space:]]*:[[:space:]]*\"$escaped\"" \
    | head -1 | grep -oE '[0-9]+' | head -1 || true)"
  if [ -n "${old_id:-}" ]; then
    echo "==> Removing the previous $name (id $old_id)"
    curl -fsS -X DELETE "${AUTH[@]}" "$API/releases/$release_id/assets/$old_id" >/dev/null
  fi
  echo "==> Uploading $name to $RELEASE_TAG"
  curl -fsS -X POST "${AUTH[@]}" "$API/releases/$release_id/assets?name=$name" \
    -F "attachment=@$path" >/dev/null
}

replace_asset "$work/latest.json" "latest.json"

# The version pair, for whoever needs to describe these bundles without rebuilding
# them — today the image build, which bakes the desktop clients in and writes each
# one a sidecar (`packaging/fetch-clients.sh`).
#
# It is published HERE, beside the manifest, because this is the step that speaks
# for what the channel serves: both files are written in the same breath from the
# same two values, so they cannot disagree about which build is current. A consumer
# deriving the version from its own checkout instead would describe these bytes
# with whatever commit it happened to be on.
#
# No `size` or `sha256` — those are per-artifact and there are four. Whoever
# downloads a bundle measures the bytes it actually got, which is the only way to
# tell a truncated download from a whole one.
printf '{\n  "version_name": "%s",\n  "version_code": "%s"\n}\n' \
  "$DISPLAY_VERSION" "$APP_VERSION" > "$work/thoughtsync-desktop.json"
replace_asset "$work/thoughtsync-desktop.json" "thoughtsync-desktop.json"

echo "==> Done. $RELEASE_TAG now advertises $DISPLAY_VERSION ($APP_VERSION) for ${#entries[@]} platform(s)."

# --- prune superseded builds from a rolling channel ---------------------------
#
# The dev release is republished on every push and its assets otherwise accumulate
# forever — an AppImage alone is ~100 MB, so a week of pushes is gigabytes on the
# Git host for builds nobody can reach (the manifest only ever names the newest).
#
# Only for a rolling channel. A versioned release must keep its assets: that IS the
# archive, and the stable pointer's URLs aim at it.
if [ "${PRUNE_OLD_ASSETS:-false}" = "true" ]; then
  echo "==> Pruning superseded assets from $RELEASE_TAG"
  # Re-read: the manifest upload above changed the asset list.
  current="$(curl -sS "${AUTH[@]}" "$API/releases/$release_id/assets")"
  printf '%s' "$current" \
    | grep -oE '"id"[[:space:]]*:[[:space:]]*[0-9]+[^}]*"name"[[:space:]]*:[[:space:]]*"[^"]+"' \
    | while IFS= read -r row; do
        asset_id="$(printf '%s' "$row" | grep -oE '[0-9]+' | head -1)"
        asset_name="$(printf '%s' "$row" | sed -E 's/.*"name"[[:space:]]*:[[:space:]]*"([^"]+)".*/\1/')"
        # Keep FIXED-NAME assets and everything belonging to the current build.
        #
        # A fixed name is self-limiting: each publish replaces that same name, so
        # it cannot accumulate and the reason this prune exists does not apply to
        # it. It is also the only kind of URL that stays addressable on a rolling
        # tag, which is the whole point of having one — deleting it breaks
        # whatever was pointing at it.
        #
        # The Android client is on that list for a second reason too: it is built
        # by a DIFFERENT workflow with its own run number, so its version never
        # matches $APP_VERSION here and a version-stamped name would be pruned on
        # every desktop push regardless. That is exactly what happened on run
        # 4098, which swept the APK run 4092 had just published.
        case "$asset_name" in
          latest.json|thoughtsync-desktop.json|thoughtsync.apk|thoughtsync-android.json) continue ;;
          *"$APP_VERSION"*) continue ;;
        esac
        echo "    removing $asset_name"
        curl -fsS -X DELETE "${AUTH[@]}" "$API/releases/$release_id/assets/$asset_id" >/dev/null || \
          echo "    (couldn't remove $asset_name — leaving it)" >&2
      done
fi