# This file is part of term_utils.
#
# term_utils is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, version 3 of the License.
#
# term_utils is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with term_utils.  If not, see <https://www.gnu.org/licenses/>.
module TermUtils
  module Tab
    # Represents a table.
    class Table
      # @return [Symbol]
      attr_accessor :id
      # @return [Array<Tab::Column>]
      attr_accessor :columns
      # @param opts [Hash]
      # @option opts [Symbol] :id
      def initialize(opts = {})
        @id = opts.fetch(:id, nil)
        @columns = []
      end
      # Defines a column.
      # @param id [Symbol]
      # @param opts [Hash]
      # @option opts [Integer] :width
      # @return [Tab::Column]
      def define_column(id, opts = {}, &block)
        col = @columns.find { |c| c.id == id }
        if col
          block.call(col) if block
          col.validate
        else
          opts[:id] = id
          opts[:index] = @columns.length
          col = Column.new(opts)
          block.call(col) if block
          col.validate
          @columns << col
        end
        col
      end
      # Finds a column.
      # @param id [Symbol]
      # @return [Tab::Column, nil]
      def find_column(id)
        @columns.find { |c| c.id == id }
      end
      # Creates a new table printer.
      # @param io [IO]
      # @param values [Array<Object>, Hash<Symbol, Object>]
      # @param opts [Hash]
      # @option opts [Integer] :offset
      # @option opts [Integer] :column_separator_width
      # @return [Tab::Printer]
      def printer(io, opts = {}, &block)
        ptr = Printer.new(self, io, opts)
        block.call(ptr) if block
        ptr
      end
      # Prints a header row.
      # @param io [IO]
      # @param values [Array<Object>, Hash<Symbol, Object>]
      # @param opts [Hash]
      # @option opts [Integer] :offset
      # @option opts [Integer] :column_separator_width
      # @return [nil]
      def print_header(io, values = nil, opts = {})
        vals = values
        if values.nil?
          vals = @columns.map { |col| col.id.to_s }
        elsif values.is_a? Hash
          vals = []
          @columns.each do |col|
            vals << values[col.id]
          end
        end
        raise "wrong values (not array)" unless vals.is_a? Array
        offset = opts.fetch(:offset, 0)
        column_separator_width = opts.fetch(:column_separator_width, 2)
        sb = StringIO.new
        sb << " " * offset if offset > 0
        @columns.each do |col|
          sb << " " * column_separator_width if col.index > 0
          sb << col.render_header(vals[col.index])
        end
        io.puts sb.string
      end
      # Prints a data row.
      # @param io [IO]
      # @param values [Array<Object>, Hash<Symbol, Object>]
      # @param opts [Hash]
      # @option opts [Integer] :offset
      # @option opts [Integer] :column_separator_width
      # @return [nil]
      def print_data(io, values, opts = {})
        vals = values
        if values.is_a? Hash
          vals = []
          @columns.each do |col|
            vals << values[col.id]
          end
        end
        raise "wrong values (not array)" unless vals.is_a? Array
        offset = opts.fetch(:offset, 0)
        column_separator_width = opts.fetch(:column_separator_width, 2)
        sb = StringIO.new
        sb << " " * offset if offset > 0
        @columns.each do |col|
          sb << " " * column_separator_width if col.index > 0
          sb << col.render_data(vals[col.index])
        end
        io.puts sb.string
      end
      # Prints a separator row.
      # @param io [IO]
      # @param opts [Hash]
      # @option opts [Integer] :offset
      # @option opts [Integer] :column_separator_width
      # @return [nil]
      def print_separator(io, opts = {})
        offset = opts.fetch(:offset, 0)
        column_separator_width = opts.fetch(:column_separator_width, 2)
        sb = StringIO.new
        sb << " " * offset if offset > 0
        @columns.each do |col|
          sb << " " * column_separator_width if col.index > 0
          sb << "-" * col.width
        end
        io.puts sb.string
      end
      # Returns column titles.
      # @return [Hash<Symbol, String>]
      def titles
        h = {}
        @columns.each do |col|
          h[col.id] = col.id.to_s
        end
        h
      end
    end
    # Represents a table column.
    class Column
      # @return [Symbol]
      attr_accessor :id
      # @return [Integer]
      attr_accessor :index
      # @return [Integer]
      attr_accessor :width
      # @return [Symbol] `:left`, `:right`.
      attr_accessor :align
      # @return [Boolean]
      attr_accessor :fixed
      # @return [String]
      attr_accessor :ellipsis
      # @return [Proc, String, nil]
      attr_accessor :format
      # @param opts [Hash]
      # @option opts [Symbol] :id
      # @option opts [Integer] :index
      # @option opts [Integer] :width
      # @option opts [Symbol] :align
      # @option opts [Boolean] :fixed
      # @option opts [String] :ellipsis
      # @option opts [Proc, String, nil] :format
      def initialize(opts = {})
        @id = opts.fetch(:id)
        @index = opts.fetch(:index)
        @width = opts.fetch(:width, 8)
        @align = opts.fetch(:align, :left)
        @fixed = opts.fetch(:fixed, false)
        @ellipsis = opts.fetch(:ellipsis, "?")
        @format = opts.fetch(:format, nil)
      end
      # Validates the column represented by this one.
      # @return [nil]
      def validate
        raise "missing column id (nil)" if @id.nil?
        raise "missing column index (nil)" if @index.nil?
        raise "wrong column index (not integer)" unless @index.is_a? Integer
        raise "wrong column index (not >= 0)" if @index < 0
        raise "missing column width (nil)" if @width.nil?
        raise "wrong column width (not integer)" unless @width.is_a? Integer
        raise "wrong column width (not > 0)" if @width <= 0
        raise "wrong column align (not :left or :right)" unless %i{left right}.index @align
      end
      # Aligns and cuts a given string.
      # @param str [String]
      # @return [String]
      def align_cut(str)
        if @align == :left
          # Align left
          if @fixed and (str.length > @width)
            str = "#{str[0..(@width - (@ellipsis.length + 1))]}#{@ellipsis}"
          else
            str = "%-*s" % [@width, str]
          end
        else
          # Align right
          if @fixed and (str.length > @width)
            str = "#{@ellipsis}#{str[(str.length - @width + @ellipsis.length)..(str.length - 1)]}"
          else
            str = "%*s" % [@width, str]
          end
        end
        str
      end
      # Renders a given header.
      # @param v [Object]
      # return [String]
      def render_header(v)
        str = v
        str = str.to_s unless str.is_a? String
        align_cut str
      end
      # Renders a given value.
      # @param v [Object]
      # return [String]
      def render_data(v)
        str = v
        if v
          if @format.is_a? Proc
            str = @format.call(v)
          elsif @format.is_a? String
            str = @format % v
          end
        end
        str = str.to_s unless str.is_a? String
        align_cut str
      end
    end
    # Represents a table printer.
    class Printer
      # @return [Tab::Table]
      attr_accessor :table
      # @return [IO]
      attr_accessor :io
      # @return [Hash]
      attr_accessor :options
      # @param table [Tab::Table]
      # @param io [IO]
      # @param options [Hash]
      def initialize(table, io, options)
        @table = table
        @io = io
        @options = options
      end
      def line
        @io.puts ""
      end
      def header(values = nil, opts = {})
        @table.print_header(@io, values, @options.merge(opts))
      end
      def data(values, opts = {})
        @table.print_data(@io, values, @options.merge(opts))
      end
      # Prints a separator.
      # @param opts [Hash]
      # @option opts [Integer] :offset
      # @option opts [Integer] :column_separator_width
      # @return [nil]
      def separator(opts = {})
        @table.print_separator(@io, @options.merge(opts))
      end
    end
    # Represents a holder of tables.
    class Holder
      # @return [Hash<Symbol, Tab::Table>]
      attr_accessor :tables
      def initialize(opts = {})
        @tables = {}
      end
      # Defines a table.
      # @param id [Symbol]
      # @param opts [Hash]
      # @return [Tab::Table]
      def define_table(id, opts = {}, &block)
        if @tables.has_key? id
          block.call(@tables[id]) if block
        else
          opts[:id] = id
          new_tab = Table.new(opts)
          block.call(new_tab) if block
          @tables[id] = new_tab
        end
        @tables[id]
      end
      # Finds a table.
      # @param id [Symbol]
      # @return [Tab::Table, nil]
      def find_table(id)
        @tables[id]
      end
      # Creates a new table printer.
      # @param id [Symbol]
      # @param io [IO]
      # @param values [Array<Object>, Hash<Symbol, Object>]
      # @param opts [Hash]
      # @option opts [Integer] :offset
      # @option opts [Integer] :column_separator_width
      # @return [Tab::Printer]
      def printer(id, io, opts = {}, &block)
        find_table(id).printer(io, opts, &block)
      end
    end
    @@default_holder = Holder.new
    # Defines a table.
    # @param id [Symbol]
    # @param opts [Hash]
    # @return [Tab::Table]
    def self.define_table(id, opts = {}, &block)
      @@default_holder.define_table(id, opts = {}, &block)
    end
    # Creates a new table printer.
    # @param id [Symbol]
    # @param io [IO]
    # @param values [Array<Object>, Hash<Symbol, Object>]
    # @param opts [Hash]
    # @option opts [Integer] :offset
    # @option opts [Integer] :column_separator_width
    # @return [Tab::Printer]
    def self.printer(id, io, opts = {}, &block)
      @@default_holder.find_table(id).printer(io, opts, &block)
    end
  end
end