require "yaml"

module Backlog
  # The parsed contents of a repo's `.cc-os/config` (YAML). Only the
  # `board` key matters to the resolver: an explicit board-name override.
  # Never touches the filesystem itself — callers read the file and pass
  # its contents (or nil, if absent) in.
  class Config
    def initialize(contents)
      @data = contents.to_s.strip.empty? ? {} : (YAML.safe_load(contents) || {})
    rescue Psych::SyntaxError
      @data = {}
    end

    # @return [String, nil] the explicit board name override, if configured
    def board
      @data["board"]
    end

    # @return [String, nil] the tracker key (e.g. "forgejo:owner/repo"), if configured
    def tracker
      @data["tracker"]
    end

    def configured? = !board.nil?
    def tracker_configured? = !tracker.nil?

    # @return [Hash] a copy of the parsed config data
    def to_h = @data.dup

    # Return new YAML contents with `key` set to `value`, preserving every
    # other key already present in `contents`. Pure — does not touch the
    # filesystem; callers read/write the file themselves.
    #
    # @param contents [String, nil] existing raw `.cc-os/config` contents
    # @param key [String, Symbol] key to set
    # @param value [Object] value to set it to
    # @return [String] the updated YAML contents
    def self.merge(contents, key, value)
      data = new(contents).to_h
      data[key.to_s] = value
      YAML.dump(data)
    end
  end
end