require 'json'
require 'fileutils'

# .version file representation, see Carthage documentation on them:
# https://github.com/Carthage/Carthage/blob/master/Documentation/VersionFile.md
class VersionFile

    attr_reader :path, :version, :frameworks_by_platform

    def initialize(path)
        @path = path
        parse
    end

    # Returns a Hash, e.g.
    # ```
    # {
    #   "CocoaLumberjack" => [:iOS, :watchOS],
    #   "Lottie" => [:iOS],
    # }
    # ```
    def platforms_by_framework
        result = Hash.new { |h, k| h[k] = [] }
        for framework_name in framework_names do
            @frameworks_by_platform.each do |platform, framework_names_in_platform|
                if framework_names_in_platform.include?(framework_name)
                    result[framework_name] << platform
                end
            end
        end
        result
    end

    # Unique array of framework names.
    def framework_names
        @frameworks_by_platform.values.flatten.uniq.sort
    end

    # Total number of frameworks accross all platforms.
    def number_of_frameworks
        @frameworks_by_platform.values.flatten.count
    end

    def move_to_build_dir
        basename = File.basename(@path)
        target_path = File.join(CARTHAGE_BUILD_DIR, basename)
        FileUtils.mv(@path, target_path)
        @path = target_path
    end

    def remove
        FileUtils.rm(@path)
    end

    def same_content?(other_version_file)
        if other_version_file.nil?
            false
        else
            FileUtils.compare_file(@path, other_version_file.path)
        end
    end

    private

    def parse
        raise AppError.new, "File #{path} doesn't exist, has carthage been bootstrapped?" unless File.exist?(@path)

        file = File.read(@path)
        json = JSON.parse(file)

        @version = json['commitish']
        raise AppError.new, "Version is missing in #{@path}" if @version.nil? || @version.empty?

        @frameworks_by_platform = {
            :iOS => parse_platform_array(json['iOS']),
            :macOS => parse_platform_array(json['Mac']),
            :tvOS => parse_platform_array(json['tvOS']),
            :watchOS => parse_platform_array(json['watchOS']),
        }
    end

    def parse_platform_array(array)
        if array.kind_of?(Array)
            array.map { |entry| entry['name'] }
        else
            []
        end
    end

end