buren/honey_format

# frozen_string_literal: true

module HoneyFormat
  # Represents Matrix.
  class Matrix
    # Instantiate Matrix.
    # @return [Matrix] a new instance of Matrix.
    # @param [Array<Array<String, nil>>] matrix
    # @param header [Array<String>]
    #   header optional argument that represents header, required if the matrix
    #   lacks a header row.
    # @param header_converter [#call] converts header columns.
    # @param header_deduplicator [#call] deduplicates header columns.
    # @param row_builder [#call] will be called for each parsed row.
    # @param type_map [Hash] map of column_name => type conversion to perform.
    # @raise [HeaderError] super class of errors raised when there is a header error.
    # @raise [MissingHeaderError] raised when header is missing (empty or nil).
    # @raise [MissingHeaderColumnError] raised when header column is missing.
    # @raise [RowError] super class of errors raised when there is a row error.
    # @raise [EmptyRowColumnsError] raised when row columns are empty.
    # @raise [InvalidRowLengthError] raised when row has more columns than header columns.
    # @example
    #   matrix = HoneyFormat::Matrix.new([%w[name id], %w[jacob 1]])
    #   matrix.columns # => [:name, :id]
    #   matrix.rows.to_a # => [#<Row name="jacob", id="1">]
    # @example With custom header converter
    #   converter = proc { |v| v == 'name' ? 'first_name' : v }
    #   matrix = HoneyFormat::Matrix.new([%w[name id]], header_converter: converter)
    #   matrix.columns # => [:first_name, :id]
    # @example Handle errors
    #   begin
    #     matrix = HoneyFormat::Matrix.new([%w[name id]])
    #   rescue HoneyFormat::HeaderError => e
    #     puts "header error: #{e.class}, #{e.message}"
    #   rescue HoneyFormat::RowError => e
    #     puts "row error: #{e.class}, #{e.message}"
    #   end
    # @see Header#initialize
    # @see Rows#initialize
    def initialize(
      matrix,
      header: nil,
      header_converter: HoneyFormat.header_converter,
      header_deduplicator: HoneyFormat.config.header_deduplicator,
      row_builder: nil,
      type_map: {}
    )
      header_row = header || matrix.shift
      @header = Header.new(
        header_row,
        converter: header_converter,
        deduplicator: header_deduplicator
      )
      @type_map = type_map.select { |key, _v| @header.columns.include?(key) }.to_h
      @rows = Rows.new(matrix, columns, builder: row_builder, type_map: @type_map)
    end

    # Original matrix header
    # @return [Header] object representing the matrix header.
    def header
      @header
    end

    # Matrix columns converted from the original Matrix header
    # @return [Array<Symbol>] of column identifiers.
    def columns
      @header.to_a
    end

    # Matrix type map used
    # @return [Hash<Symbol, Symbol>] the type map used.
    def type_map
      @type_map
    end

    # Return rows
    # @return [Rows] rows.
    def rows
      @rows
    end

    # Itereate over each row
    # @yield [row] The given block will be passed for every row.
    # @yieldparam [Row] row in the matrix.
    # @return [Enumerator] If no block is given, an enumerator object will be returned.
    def each_row
      return rows.each unless block_given?

      rows.each { |row| yield(row) }
    end

    # Convert matrix to CSV-string.
    # @param columns [Array<Symbol>, Set<Symbol>, NilClass]
    #   the columns to output, nil means all columns (default: nil)
    # @yield [row]
    #   The given block will be passed for every row - return truthy if you want the
    #   row to be included in the output
    # @yieldparam [Row] row
    # @return [String] CSV-string representation.
    # @example with selected columns
    #   matrix.to_csv(columns: [:id, :country])
    # @example with selected rows
    #   matrix.to_csv { |row| row.country == 'Sweden' }
    # @example with both selected columns and rows
    #   matrix.to_csv(columns: [:id, :country]) { |row| row.country == 'Sweden' }
    def to_csv(columns: nil, &block)
      columns = columns&.map(&:to_sym)
      @header.to_csv(columns: columns) + @rows.to_csv(columns: columns, &block)
    end
  end
end