# frozen_string_literal: true

require "how_is/version"
require "how_is/report"

module HowIs
  DEFAULT_REPORT_FILE = "report.html"

  def self.new(repository, date)
    Report.new(repository, date)
  end

  ##
  # Generates a series of report files based on a config Hash.
  #
  # @param config [Hash] A Hash specifying the formats, locations, etc
  #   of the reports to generate.
  # @param date [String] A string containing the date (YYYY-MM-DD) that the
  #   report ends on. E.g., for Jan 1-Feb 1 2017, you'd pass 2017-02-01.
  def self.from_config(config, date)
    report = Report.new(config["repository"], date)
    report_data = prepare_report_metadata(config["repository"], date)

    generated_reports =
      config["reports"].map { |format, report_config|
        # Sometimes report_data has unused keys, which generates a warning, but
        # we're okay with it, so we wrap it with silence_warnings {}.
        filename = silence_warnings { report_config["filename"] % report_data }
        file = File.join(report_config["directory"], filename)

        report_export = report.send("to_#{format}", report_config["frontmatter"])

        [file, report_export]
      }

    generated_reports.to_h
  end

  ##
  # Returns a list of possible export formats.
  #
  # @return [Array<String>] An array of the types of reports you can generate.
  def self.supported_formats
    ["html", "json"]
  end

  def self.template(filename)
    dir  = File.expand_path("./how_is/templates/", __dir__)
    path = File.join(dir, filename)

    open(path).read
  end

  ##
  # Returns whether or not the specified +file+ can be exported to.
  #
  # @param file [String] A filename.
  # @return [Boolean] +true+ if HowIs can export to the file, +false+
  #   if it can't.
  def self.can_export_to?(file)
    # TODO: Check if the file is writable?
    supported_formats.include?(file.split(".").last)
  end

  def self.silence_warnings(&block)
    with_warnings(nil, &block)
  end
  private_class_method :silence_warnings

  def self.with_warnings(flag, &_block)
    old_verbose = $VERBOSE
    $VERBOSE = flag
    yield
  ensure
    $VERBOSE = old_verbose
  end
  private_class_method :with_warnings

  def self.prepare_report_metadata(repository, date)
    end_date = DateTime.strptime(date, "%Y-%m-%d")
    friendly_end_date = end_date.strftime("%B %d, %y")

    {
      repository: repository,
      date: end_date,
      friendly_date: friendly_end_date,
    }
  end
  private_class_method :prepare_report_metadata
end