volumen/lib/volumen/config.rb

# frozen_string_literal: true

require "toml-rb"
require "fileutils"

module Volumen
  # Loads and merges volumen configuration from a TOML file, then applies
  # command-line overrides on top of the file values and built-in defaults.
  class Config
    DEFAULT_PATH = "/etc/volumen/config.toml"

    DEFAULTS = {
      "server" => { "host" => "0.0.0.0", "port" => 9090 }.freeze,
      "content_dir" => "/var/lib/volumen/posts",
      "users_file" => "/var/lib/volumen/users.toml",
      "site" => {
        "title" => "My Blog",
        "description" => "A blog powered by volumen.",
        "base_url" => "https://example.com",
        "language" => "en",
        "author" => "Anonymous"
      }.freeze,
      "admin" => {
        "password_hash" => "",
        "session_key" => "",
        "session_ttl" => 86_400
      }.freeze
    }.freeze

    TEMPLATE = <<~TOML
      # volumen configuration.

      [server]
      host = "0.0.0.0"
      port = 9090

      # Directory of your Markdown posts (.md with TOML frontmatter).
      content_dir = "/var/lib/volumen/posts"

      # File storing admin users (managed from the admin Settings page).
      users_file = "/var/lib/volumen/users.toml"

      [site]
      title = "My Blog"
      description = "A blog powered by volumen."
      base_url = "https://example.com"
      language = "en"
      author = "Anonymous"

      [admin]
      # Bootstrap admin login: paste a hash from `volumen hash-password` to sign
      # in as user "admin". Once you manage users in Settings, users_file wins.
      password_hash = ""
      # Secret signing session cookies (>= 64 bytes). Empty = random per start.
      session_key = ""
      # Session lifetime in seconds (24h default).
      session_ttl = 86400
    TOML

    def self.load(path: DEFAULT_PATH, overrides: {})
      data = File.exist?(path) ? TomlRB.load_file(path) : {}
      merged = deep_merge(DEFAULTS, data)
      new(apply_overrides(merged, overrides))
    end

    # Writes the commented template to `path` if it does not exist yet.
    # Returns the path on success, or nil if it already existed or could not
    # be created.
    def self.generate_default(path)
      return nil if File.exist?(path)

      FileUtils.mkdir_p(File.dirname(path))
      File.write(path, TEMPLATE)
      path
    rescue SystemCallError
      nil
    end

    def self.deep_merge(base, override)
      result = {}
      base.each do |key, base_val|
        result[key] = if override.key?(key)
                        merge_leaf(base_val, override[key])
                      elsif base_val.is_a?(Hash)
                        {}.merge(base_val)
                      else
                        base_val
                      end
      end
      override.each do |key, val|
        result[key] = val unless result.key?(key)
      end
      result
    end

    def self.merge_leaf(base_val, override_val)
      if base_val.is_a?(Hash) && override_val.is_a?(Hash)
        deep_merge(base_val, override_val)
      else
        override_val
      end
    end

    def self.apply_overrides(data, overrides)
      server = data["server"].dup
      server["host"] = overrides[:host] if overrides[:host]
      server["port"] = overrides[:port] if overrides[:port]

      result = data.dup
      result["server"] = server
      result["content_dir"] = overrides[:content] if overrides[:content]
      result
    end

    private_class_method :deep_merge, :apply_overrides

    attr_reader :data

    def initialize(data)
      @data = data
    end

    def host
      @data["server"]["host"]
    end

    def port
      @data["server"]["port"]
    end

    def content_dir
      @data["content_dir"]
    end

    def users_file
      @data["users_file"]
    end

    def site
      @data["site"]
    end

    def language
      @data["site"]["language"]
    end

    def admin
      @data["admin"]
    end
  end
end