# frozen_string_literal: true

require "json"

# Public: Allows to resolve configuration sourced from `config/vite.json` and
# environment variables, combining them with the default options.
class ViteRuby::Config
  def origin
    "#{protocol}://#{host_with_port}"
  end

  def protocol
    https ? "https" : "http"
  end

  def host_with_port
    "#{host}:#{port}"
  end

  # Internal: Path to the manifest files generated by Vite and vite-plugin-ruby.
  def known_manifest_paths
    [
      # NOTE: Generated by Vite when `manifest: true`, which vite-plugin-ruby enables.
      build_output_dir.join(".vite/manifest.json"),

      # NOTE: Path where vite-plugin-ruby outputs the assets manifest file.
      build_output_dir.join(".vite/manifest-assets.json"),
    ]
  end

  # Internal: Path to the manifest files generated by Vite and vite-plugin-ruby.
  def manifest_paths
    known_manifest_paths.select(&:exist?)
  end

  # Public: The directory where Vite will store the built assets.
  def build_output_dir
    root.join(public_dir, public_output_dir)
  end

  # Public: The directory where the entries are located.
  def resolved_entrypoints_dir
    vite_root_dir.join(entrypoints_dir)
  end

  # Internal: The directory where Vite stores its processing cache.
  def vite_cache_dir
    root.join("node_modules/.vite")
  end

  # Public: The directory that Vite uses as root.
  def vite_root_dir
    root.join(source_code_dir)
  end

  # Public: Loads an optional config/vite.rb file that can modify ViteRuby.env
  def load_ruby_config
    rb_config_path = File.expand_path(config_path.sub(/.json$/, ".rb"), root)
    load rb_config_path if File.exist?(rb_config_path)
  end

  # Public: Sets additional environment variables for vite-plugin-ruby.
  def to_env(env_vars = ViteRuby.env)
    CONFIGURABLE_WITH_ENV.each_with_object({}) do |option, env|
      unless (value = @config[option]).nil?
        env["#{ViteRuby::ENV_PREFIX}_#{option.upcase}"] = value.to_s
      end
    end.merge(env_vars)
  end

  # Internal: Files and directories that should be watched for changes.
  def watched_paths
    [
      *(watch_additional_paths + additional_entrypoints).reject { |dir|
        dir.start_with?("~/") || dir.start_with?(source_code_dir)
      },
      "#{source_code_dir}/**/*",
      config_path.sub(/.json$/, ".{rb,json}"),
      *DEFAULT_WATCHED_PATHS,
    ].freeze
  end

  # Internal: Changes the current directory to the root dir.
  def within_root(&block)
    Dir.chdir(File.expand_path(root), &block)
  end

private

  # Internal: Coerces all the configuration values, in case they were passed
  # as environment variables which are always strings.
  def coerce_values(config)
    config["mode"] = config["mode"].to_s
    config["port"] = config["port"].to_i
    config["root"] = root = Pathname.new(config["root"])
    config["build_cache_dir"] = root.join(config["build_cache_dir"])
    config["ssr_output_dir"] = root.join(config["ssr_output_dir"])
    coerce_booleans(config, "auto_build", "hide_build_console_output", "https", "skip_compatibility_check", "skip_proxy")
    config["package_manager"] ||= detect_package_manager(root)
  end

  # Internal: Coerces configuration options to boolean.
  def coerce_booleans(config, *names)
    truthy = [true, "true"]
    names.each { |name| config[name] = truthy.include?(config[name]) }
  end

  def detect_package_manager(root)
    return "npm" if root.join("package-lock.json").exist?
    return "pnpm" if root.join("pnpm-lock.yaml").exist?
    return "bun" if root.join("bun.lockb").exist?
    return "yarn" if root.join("yarn.lock").exist?

    "npm"
  end

  def initialize(attrs)
    @config = attrs.tap { |config| coerce_values(config) }.freeze
    ViteRuby::CompatibilityCheck.verify_plugin_version(root) unless skip_compatibility_check
  end

  class << self
    private :new

    # Public: Returns the project configuration for Vite.
    def resolve_config(**attrs)
      config = config_defaults.merge(attrs.transform_keys(&:to_s))
      file_path = File.join(config["root"], config["config_path"])
      file_config = config_from_file(file_path, mode: config["mode"])
      new DEFAULT_CONFIG.merge(file_config).merge(config_from_env).merge(config)
    end

  private

    # Internal: Converts camelCase to snake_case.
    SNAKE_CASE = ->(camel_cased_word) {
      camel_cased_word.to_s.gsub("::", "/")
        .gsub(/([A-Z]+)([A-Z][a-z])/, '\1_\2')
        .gsub(/([a-z\d])([A-Z])/, '\1_\2')
        .tr("-", "_")
        .downcase
    }

    # Internal: Default values for a Ruby application.
    def config_defaults(asset_host: nil, mode: ENV.fetch("RACK_ENV", "development"), root: Dir.pwd)
      {
        "asset_host" => option_from_env("asset_host") || asset_host,
        "config_path" => option_from_env("config_path") || DEFAULT_CONFIG.fetch("config_path"),
        "mode" => option_from_env("mode") || mode,
        "root" => option_from_env("root") || root,
      }.select { |_, value| value }
    end

    # Internal: Used to load a JSON file from the specified path.
    def load_json(path)
      JSON.parse(File.read(File.expand_path(path))).each do |_env, config|
        config.transform_keys!(&SNAKE_CASE) if config.is_a?(Hash)
      end.tap do |config|
        config.transform_keys!(&SNAKE_CASE)
      end
    end

    # Internal: Retrieves a configuration option from environment variables.
    def option_from_env(name)
      ViteRuby.env["#{ViteRuby::ENV_PREFIX}_#{name.upcase}"]
    end

    # Internal: Extracts the configuration options provided as env vars.
    def config_from_env
      CONFIGURABLE_WITH_ENV.each_with_object({}) do |option, env_vars|
        if value = option_from_env(option)
          env_vars[option] = value
        end
      end
    end

    # Internal: Loads the configuration options provided in a JSON file.
    def config_from_file(path, mode:)
      multi_env_config = load_json(path)
      multi_env_config.fetch("all", {})
        .merge(multi_env_config.fetch(mode, {}))
    rescue Errno::ENOENT => error
      $stderr << "Check that your vite.json configuration file is available in the load path:\n\n\t#{error.message}\n\n"
      {}
    end
  end

  # Internal: Shared configuration with the Vite plugin for Ruby.
  DEFAULT_CONFIG = load_json("#{__dir__}/../../default.vite.json").freeze

  # Internal: Configuration options that can not be provided as env vars.
  NOT_CONFIGURABLE_WITH_ENV = %w[additional_entrypoints watch_additional_paths].freeze

  # Internal: Configuration options that can be provided as env vars.
  CONFIGURABLE_WITH_ENV = (DEFAULT_CONFIG.keys + %w[mode root] - NOT_CONFIGURABLE_WITH_ENV).freeze

  # Internal: If any of these files is modified the build won't be skipped.
  DEFAULT_WATCHED_PATHS = %w[
    bun.lockb
    package-lock.json
    package.json
    pnpm-lock.yaml
    postcss.config.js
    tailwind.config.js
    vite.config.js
    vite.config.mjs
    vite.config.mts
    vite.config.ts
    windi.config.ts
    yarn.lock
  ].freeze

public

  # Define getters for the configuration options.
  (CONFIGURABLE_WITH_ENV + NOT_CONFIGURABLE_WITH_ENV).each do |option|
    define_method(option) { @config[option] }
  end
end