require 'optparse'
require 'csv'

module Uplot
  class Command
    def initialize(argv)
      @params = {}
      @ptype = nil
      @headers = nil
      @delimiter = "\t"
      @output = false
      parse_options(argv)
    end

    def create_parser
      OptionParser.new do |opt|
        opt.on('-o', '--output', TrueClass)     { |v| @output = v }
        opt.on('-d', '--delimiter VAL', String) { |v| @delimiter = v }
        opt.on('-H', '--headers', TrueClass)    { |v| @headers = v }
        opt.on('-t', '--title VAL', String)     { |v| @params[:title] = v }
        opt.on('-w', '--width VAL', Numeric)    { |v| @params[:width] = v }
        opt.on('-h', '--height VAL', Numeric)   { |v| @params[:height] = v }
        opt.on('-b', '--border VAL', Numeric)   { |v| @params[:border] = v }
        opt.on('-m', '--margin VAL', Numeric)   { |v| @params[:margin] = v }
        opt.on('-p', '--padding VAL', Numeric)  { |v| @params[:padding] = v }
        opt.on('-l', '--labels', TrueClass)     { |v| @params[:labels] = v }
      end
    end

    def parse_options(argv)
      main_parser            = create_parser
      parsers                = Hash.new { |h, k| h[k] = create_parser }
      parsers['hist']        .on('--nbins VAL', Numeric) { |v| @params[:nbins] = v }
      parsers['histogram']   = parsers['hist']
      parsers['lineplot']    = parsers['line']
      parsers['lineplots']   = parsers['lines']
      parsers['scatterplot'] = parsers['scatter']
      parsers['barplot']     = parsers['bar']
      parsers['boxplot']     = parsers['box']
      parsers.default        = nil

      main_parser.banner = <<~MSG
        Usage:\tuplot <command> [options]
        Command:\t#{parsers.keys.join(' ')}
      MSG
      main_parser.order!(argv)
      @ptype = argv.shift

      unless parsers.has_key?(@ptype)
        warn "unrecognized command '#{@ptype}'"
        exit 1
      end
      parser = parsers[@ptype]
      parser.parse!(argv) unless argv.empty?
    end

    def run
      # Sometimes the input file does not end with a newline code.
      while input = Kernel.gets(nil)
        input.freeze
        data, headers = preprocess(input)
        case @ptype
        when 'hist', 'histogram'
          histogram(data, headers)
        when 'line', 'lineplot'
          line(data, headers)
        when 'lines'
          lines(data, headers)
        when 'scatter', 'scatterplot'
          scatter(data, headers)
        when 'bar', 'barplot'
          barplot(data, headers)
        when 'box', 'boxplot'
          boxplot(data, headers)
        end.render($stderr)

        print input if @output
      end
    end

    def preprocess(input)
      data = CSV.parse(input, col_sep: @delimiter)
      if @headers
        headers = data.shift
        data = data.transpose
        [data, headers]
      else
        data = data.transpose
        [data, nil]
      end
    end

    def barplot(data, headers)
      @params[:title] ||= headers[1] if headers
      UnicodePlot.barplot(data[0], data[1].map(&:to_f), **@params)
    end

    def histogram(data, headers)
      @params[:title] ||= headers[0] if headers # labels?
      series = data[0].map(&:to_f)
      UnicodePlot.histogram(series, **@params.compact)
    end

    def line(data, headers)
      if data.size == 1
        @params[:name] ||= headers[0] if headers
        y = data[0]
        x = (1..y.size).to_a
      else
        @params[:name] ||= headers[1] if headers
        x = data[0]
        y = data[1]
      end
      x = x.map(&:to_f)
      y = y.map(&:to_f)
      UnicodePlot.lineplot(x, y, **@params.compact)
    end

    def lines(data, headers)
      data.map! { |series| series.map(&:to_f) }
      @params[:name] ||= headers[1] if headers
      plot = UnicodePlot.lineplot(data[0], data[1], **@params.compact)
      2.upto(data.size - 1) do |i|
        UnicodePlot.lineplot!(plot, data[0], data[i], name: headers[i])
      end
      plot
    end

    def scatter(data, headers)
      data.map! { |series| series.map(&:to_f) }
      @params[:name] ||= headers[1] if headers
      plot = UnicodePlot.scatterplot(data[0], data[1], **@params.compact)
      2.upto(data.size - 1) do |i|
        UnicodePlot.scatterplot!(plot, data[0], data[i], name: headers[i])
      end
      plot
    end

    def boxplot(data, headers)
      headers ||= (1..data.size).to_a
      data.map! { |series| series.map(&:to_f) }
      plot = UnicodePlot.boxplot(headers[0], data[0], **@params.compact)
      1.upto(data.size - 1) do |i|
        UnicodePlot.boxplot!(plot, headers[i], data[i])
      end
      plot
    end
  end
end