feat: parse .nvmrc .node-version files. (#7)

* feat: support parse legacy file

* feat: support parse legacy file

hooks/parse_legacy_file.lua

@@ -0,0 +1,85 @@
+--- Parse the legacy file found by vfox to determine the version of the tool.
+--- Useful to extract version numbers from files like JavaScript's package.json or Golangs go.mod.
+function PLUGIN:ParseLegacyFile(ctx)
+    local filepath = ctx.filepath
+    local file = io.open(filepath, "r")
+    local content = file:read("*a")
+    file:close()
+    content = content:gsub("%s+", "")
+    if content == "" then
+        return {}
+    end
+    function resolve_legacy_version(strategy, query)
+        local list = {}
+
+        if strategy == "latest_installed" then
+            list = ctx:getInstalledVersions()
+        elseif strategy == "latest_available" then
+            for _, av in pairs(self:Available({})) do
+                table.insert(list, av.version)
+            end
+        else
+            -- Just return the original query
+            return query
+        end
+
+        local resolved = ""
+        for _, item in pairs(list) do
+            if item:match("^" .. query) then
+                resolved = item
+                break
+            end
+        end
+
+        if resolved ~= "" then
+            return resolved
+        elseif strategy ~= "latest_available" then
+            -- If no version is installed, fallback to latest_available
+            return resolve_legacy_version("latest_available", query)
+        else
+            -- Give up and pretty the query itself
+            return query
+        end
+    end
+    local query = resolve_version(content)
+
+    query = resolve_legacy_version("latest_installed", query)
+
+    return {
+        version = query
+    }
+end
+
+function resolve_version(query)
+    query = string.lower(query:gsub("v", ""))
+
+    if query:match("^lts-") then
+        query = query:gsub("-", "/")
+    end
+
+    local nodejs_codenames = {
+        argon = 4,
+        boron = 6,
+        carbon = 8,
+        dubnium = 10,
+        erbium = 12,
+        fermium = 14,
+        gallium = 16,
+        hydrogen = 18,
+        iron = 20
+    }
+
+    for codename, version_number in pairs(nodejs_codenames) do
+        if query == "lts/" .. codename then
+            query = tostring(version_number)
+            break
+        end
+    end
+
+    if query == "lts" or query == "lts/*" then
+        query = tostring(nodejs_codenames[#nodejs_codenames])
+    end
+
+    return query
+end
+

metadata.lua

@@ -14,7 +14,14 @@ PLUGIN.license = "Apache 2.0"
 PLUGIN.description = "Node.js runtime environment."
 
 --- !!! OPTIONAL !!!
--- minimum compatible vfox version
+--- minimum compatible vfox version
 PLUGIN.minRuntimeVersion = "0.3.0"
--- Some things that need user to be attention!
+--- Some things that need user to be attention!
 PLUGIN.notes = {}
+
+--- List legacy configuration filenames for determining the specified version of the tool.
+--- such as ".node-version", ".nvmrc", etc.
+PLUGIN.legacyFilenames = {
+    ".node-version",
+    ".nvmrc"
+}