Arcadelux update script added.

.includes/functions.sh

@@ -251,3 +251,166 @@ install_with_progress() {
             ;;
     esac
 }
+
+# Return the latest GitHub release tag and one matching asset URL, one per line.
+github_latest_release() {
+    local repo="$1"
+    local assetFilter="$2"
+    local response tag
+    local -a assetUrls=()
+
+    if [[ -z "$repo" || "$repo" != */* ]]; then
+        echo "Expected a GitHub repository in owner/repo format." >&2
+        return 1
+    fi
+
+    if ! response="$(curl -fsSL --retry 3 "https://api.github.com/repos/${repo}/releases/latest")"; then
+        echo "Could not fetch the latest release for ${repo}." >&2
+        return 1
+    fi
+
+    tag="$(sed -n 's/.*"tag_name"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/p' <<< "$response" | head -n1)"
+    mapfile -t assetUrls < <(
+        sed -n 's/.*"browser_download_url"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/p' <<< "$response"
+    )
+    if [[ -n "$assetFilter" ]]; then
+        mapfile -t assetUrls < <(
+            printf '%s\n' "${assetUrls[@]}" | grep -iF -- "$assetFilter"
+        )
+    fi
+
+    if [[ -z "$tag" || ${#assetUrls[@]} -ne 1 ]]; then
+        echo "Could not identify one matching release asset for ${repo}." >&2
+        return 1
+    fi
+
+    printf '%s\n%s\n' "$tag" "${assetUrls[0]}"
+}
+
+# Install or replace a game from its latest GitHub release.
+# Arguments: repository, asset filter, destination, expected executable, and
+# zero or more relative paths or files to preserve from the old installation.
+update_github_release_game() {
+    local repo="$1"
+    local assetFilter="$2"
+    local destination="$3"
+    local expectedExecutable="$4"
+    shift 4
+    local -a preservePaths=("$@")
+    local -a releaseInfo=() executablePaths=() pathParts=()
+    local releaseInfoText installedVersion latestTag latestUrl archiveFile
+    local stageRoot archiveRoot newRoot executablePath preservePath sourcePath targetPath pathPart
+    local updateFailed="false"
+
+    githubReleaseGameStatus="checking"
+    destination="${destination%/}"
+    if [[ -z "$destination" || "$destination" != /* ]]; then
+        echo "The game destination must be an absolute path." >&2
+        return 1
+    fi
+
+    for preservePath in "${preservePaths[@]}"; do
+        if [[ "$preservePath" == /* ]]; then
+            echo "Preserve paths must be relative to the game directory: ${preservePath}" >&2
+            return 1
+        fi
+        IFS='/' read -r -a pathParts <<< "$preservePath"
+        for pathPart in "${pathParts[@]}"; do
+            if [[ -z "$pathPart" || "$pathPart" == "." || "$pathPart" == ".." ]]; then
+                echo "Invalid preserve path: ${preservePath}" >&2
+                return 1
+            fi
+        done
+    done
+
+    if ! releaseInfoText="$(github_latest_release "$repo" "$assetFilter")"; then
+        return 1
+    fi
+    mapfile -t releaseInfo <<< "$releaseInfoText"
+    latestTag="${releaseInfo[0]}"
+    latestUrl="${releaseInfo[1]}"
+
+    if [[ -f "${destination}/.agm-version" ]]; then
+        installedVersion="$(<"${destination}/.agm-version")"
+        if [[ "$installedVersion" == "$latestTag" && -f "${destination}/${expectedExecutable}" ]]; then
+            githubReleaseGameStatus="up-to-date"
+            echo "${game:-The game} is already at ${latestTag}."
+            return 0
+        fi
+    fi
+
+    archiveFile="${latestUrl##*/}"
+    archiveFile="${archiveFile//%20/ }"
+    archiveFile="${archiveFile#*\?filename=}"
+    archiveFile="${archiveFile%\?*}"
+    rm -f "${cache}/${archiveFile}"
+    download "$latestUrl"
+
+    mkdir -p "$(dirname "$destination")"
+    stageRoot="${destination}.agm-update.$$"
+    archiveRoot="${stageRoot}/archive"
+    mkdir -p "$archiveRoot"
+
+    if ! unzip -q "${cache}/${archiveFile}" -d "$archiveRoot"; then
+        echo "Could not extract ${archiveFile}." >&2
+        rm -rf "$stageRoot"
+        return 1
+    fi
+
+    mapfile -t executablePaths < <(find "$archiveRoot" -type f -name "$expectedExecutable" -print)
+    if [[ ${#executablePaths[@]} -ne 1 ]]; then
+        echo "The release did not contain exactly one ${expectedExecutable}." >&2
+        rm -rf "$stageRoot"
+        return 1
+    fi
+    executablePath="${executablePaths[0]}"
+    newRoot="${executablePath%/*}"
+
+    for preservePath in "${preservePaths[@]}"; do
+        sourcePath="${destination}/${preservePath}"
+        [[ -e "$sourcePath" ]] || continue
+        targetPath="${newRoot}/${preservePath}"
+        if [[ -d "$sourcePath" ]]; then
+            mkdir -p "$targetPath"
+            if ! cp -a "${sourcePath}/." "$targetPath/"; then
+                echo "Could not preserve ${preservePath}." >&2
+                updateFailed="true"
+                break
+            fi
+        else
+            mkdir -p "${targetPath%/*}"
+            if ! cp -a "$sourcePath" "$targetPath"; then
+                echo "Could not preserve ${preservePath}." >&2
+                updateFailed="true"
+                break
+            fi
+        fi
+    done
+
+    if [[ "$updateFailed" == "true" ]]; then
+        rm -rf "$stageRoot"
+        return 1
+    fi
+
+    printf '%s\n' "$latestTag" > "${newRoot}/.agm-version"
+    if [[ -e "$destination" ]]; then
+        if ! mv "$destination" "${stageRoot}/old"; then
+            echo "Could not move the old installation aside." >&2
+            rm -rf "$stageRoot"
+            return 1
+        fi
+    fi
+
+    if ! mv "$newRoot" "$destination"; then
+        echo "Could not install the new version." >&2
+        if [[ -e "${stageRoot}/old" ]]; then
+            mv "${stageRoot}/old" "$destination"
+        fi
+        rm -rf "$stageRoot"
+        return 1
+    fi
+
+    rm -rf "$stageRoot"
+    githubReleaseGameStatus="updated"
+    echo "${game:-The game} has been updated to ${latestTag}."
+}