require "multi_json"

module BaiduUeditorRails
  class AssetManifest
    def self.load(manifest_path)
      YamlManifest.try(manifest_path) ||
        JsonManifest.try(manifest_path) ||
        NullManifest.new
    end
  end
end

class YamlManifest
  def self.try(manifest_path)
    yaml_file = File.join(manifest_path, "manifest.yml")
    new(yaml_file) if File.exists?(yaml_file)
  end

  def initialize(file)
    @file = file
    @manifest = YAML.load_file(file)
  end

  def append(logical_path, file)
    @manifest[logical_path] = logical_path
  end

  def remove(logical_path)
    @manifest.delete(logical_path)
  end

  def remove_digest(logical_path)
    if digested = @manifest[logical_path]
      @manifest[logical_path] = logical_path
      yield digested, logical_path if block_given?
    end
  end

  def each(pattern)
    @manifest.each_key do |asset|
      yield asset if asset =~ pattern
    end
  end

  def to_s
    dump
  end

  def dump(io=nil)
    YAML.dump(@manifest, io)
  end

  def write
    File.open(@file, "wb") { |f| dump(f) }
  end
end

class JsonManifest
  def self.try(manifest_path)
    paths = Dir[File.join(manifest_path, "manifest*.json")]
    new(paths.first) if paths.any?
  end

  def initialize(file)
    @file = file
    @manifest = MultiJson.load(File.read(file))
  end

  def append(logical_path, file)
    stat = File.stat(file)

    @manifest["assets"][logical_path] = logical_path
    @manifest["files"][logical_path] = {
      "logical_path" => logical_path,
      "mtime"        => stat.mtime.iso8601,
      "size"         => stat.size,
      "digest"       => nil
    }
  end

  def remove(logical_path)
    if digested = @manifest["assets"].delete(logical_path)
      @manifest["files"].delete(digested)
    end
  end

  def remove_digest(logical_path)
    if digested = @manifest["assets"][logical_path]
      @manifest["assets"][logical_path] = logical_path
      @manifest["files"][logical_path] = @manifest["files"].delete(digested).tap { |f| f["digest"] = nil }
      yield digested, logical_path if block_given?
    end
  end

  def each(pattern)
    @manifest["assets"].each_key do |asset|
      yield asset if asset =~ pattern
    end
  end

  def to_s
    dump
  end

  def dump
    MultiJson.dump(@manifest)
  end

  def write
    File.open(@file, "wb") { |f| f.write(dump) }
  end
end

class NullManifest
  def append(*); end
  def remove(*); end
  def remove_digest(*); end
  def each(*); end
  def write; end
end