# Copyright (C) 2019 Thomas Baron
#
# 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
  # The tab module provides a way to print formatted tables.
  module Tab
    # Represents a table error.
    class TableError < StandardError
      def initialize(msg)
        super
      end
    end
    # Creates initial column properties.
    # @return [Hash] `:offset`, `:column_separator_width`.
    def self.init_table_props
      {:offset => 0, :column_separator_width => 2}
    end
    # Creates initial column properties.
    # @return [Hash] `:width`, `:align`, `:fixed`, `:ellipsis`, `:format`.
    def self.init_column_props
      {:width => 8, :align => :left, :fixed => false, :ellipsis => "?", :format => nil}
    end
    # Assigns table properties.
    # @param target [Hash]
    # @param source [Hash] `:offset`, `:column_separator_width`.
    # @return [Hash]
    def self.assign_table_props(target, source)
      if (source.has_key? :offset) && (source[:offset].is_a? Integer) && (source[:offset] >= 0)
        target[:offset] = source[:offset]
      end
      if (source.has_key? :column_separator_width) && (source[:column_separator_width].is_a? Integer) && (source[:column_separator_width] > 0)
        target[:column_separator_width] = source[:column_separator_width]
      end
      target
    end
    # Assigns column properties.
    # @param target [Hash]
    # @param source [Hash] `:width`, `:align`, `:fixed`, `:ellipsis`, `:format`.
    # @return [Hash]
    def self.assign_column_props(target, source)
      if (source.has_key? :width) && (source[:width].is_a? Integer) && (source[:width] > 0)
        target[:width] = source[:width]
      end
      if (source.has_key? :align) && %i[left right].index(source[:align])
        target[:align] = source[:align]
      end
      if (source.has_key? :fixed) && (!!source[:fixed] == source[:fixed])
        target[:fixed] = source[:fixed]
      end
      if (source.has_key? :ellipsis) && (source[:ellipsis].is_a? String)
        target[:ellipsis] = source[:ellipsis]
      end
      if (source.has_key? :format) && ((source[:ellipsis] == nil) || (source[:ellipsis].is_a? Proc) || (source[:ellipsis].is_a? String))
        target[:format] = source[:format]
      end
      target
    end
    # Aligns and cuts a given string.
    # @param src [String]
    # @param align [Symbol] `:left`, `:right`.
    # @param fixed [Boolean] Whether the column width is fixed.
    # @param width [Integer] The column width.
    # @param ellipsis [String] The ellipsis when not fixed.
    # @return [String]
    def self.align_cut(src, align, fixed, width, ellipsis)
      res = src
      if align == :left
        # Align left
        if fixed && (src.length > width)
          if ellipsis.length >= width
            res = ellipsis[0..(width - 1)]
          else
            res = "%s%s" % [src[0..(width - (ellipsis.length + 1))], ellipsis]
          end
        else
          res = "%-*s" % [width, src]
        end
      elsif align == :right
        # Align right
        if fixed && (src.length > width)
          if ellipsis.length >= width
            res = ellipsis[0..(width - 1)]
          else
            res = "%s%s" % [ellipsis, src[(src.length - width + ellipsis.length)..(src.length - 1)]]
          end
        else
          res = "%*s" % [width, src]
        end
      end
      res
    end
    # Represents a table.
    class Table
      # @return [Symbol]
      attr_accessor :id
      # @return [Integer]
      attr_accessor :offset
      # @return [Integer]
      attr_accessor :column_separator_width
      # @return [Hash] `:width`, `:align`, `:fixed`, `:ellipsis`, `:format`.
      attr_accessor :column_defaults
      # @return [Array<Tab::Column>]
      attr_accessor :columns
      # @param opts [Hash]
      # @option opts [Symbol] :id
      # @option opts [Integer] :offset
      # @option opts [Hash] :column_defaults
      def initialize(opts = {})
        opts = TermUtils::Tab.init_table_props.merge(opts)
        @id = opts.fetch(:id, nil)
        @offset = opts.fetch(:offset)
        @column_separator_width = opts.fetch(:column_separator_width)
        if opts.has_key? :column_defaults
          @column_defaults = opts[:column_defaults].dup
        else
          @column_defaults = TermUtils::Tab.default_column_props
        end
        @columns = []
      end
      # Returns the properties of this one.
      # @return [Hash]
      def props
        {:offset => @offset, :column_separator_width => @column_separator_width}
      end
      # Sets column default properties.
      # @param opts [Hash]
      # @option opts [Integer] :width
      # @option opts [Symbol] :align
      # @option opts [Boolean] :fixed
      # @option opts [String] :ellipsis
      # @option opts [Proc, String, nil] :format
      def set_column_defaults(opts = {})
        TermUtils::Tab.assign_column_props(@column_defaults, opts)
      end
      # Defines a column.
      # @param id [Symbol]
      # @param opts [Hash]
      # @option opts [Integer] :width
      # @option opts [Symbol] :align
      # @option opts [Boolean] :fixed
      # @option opts [String] :ellipsis
      # @option opts [Proc, String, nil] :format
      # @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(@column_defaults.merge(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 [#puts]
      # @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, props.merge(opts))
        block.call(ptr) if block
        ptr
      end
      # Prints a header row.
      # @param io [#puts]
      # @param values [Array<Object>, Hash<Symbol, Object>]
      # @param opts [Hash]
      # @option opts [Integer] :offset
      # @option opts [Integer] :column_separator_width
      # @return [nil]
      # @raise [TermUtils::Tab::TableError]
      def print_header(io, values = nil, opts = {})
        vals = values
        if values.nil?
          vals = @columns.map { |col| col.header.title }
        elsif values.is_a? Hash
          vals = []
          @columns.each do |col|
            vals << values[col.id]
          end
        end
        raise TermUtils::Tab::TableError, "wrong values (not array)" unless vals.is_a? Array
        offset = opts.fetch(:offset)
        column_separator_width = opts.fetch(:column_separator_width)
        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 [#puts]
      # @param values [Array<Object>, Hash<Symbol, Object>]
      # @param opts [Hash]
      # @option opts [Integer] :offset
      # @option opts [Integer] :column_separator_width
      # @return [nil]
      # @raise [TermUtils::Tab::TableError]
      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 TermUtils::Tab::TableError, "wrong values (not array)" unless vals.is_a? Array
        offset = opts.fetch(:offset)
        column_separator_width = opts.fetch(:column_separator_width)
        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 [#puts]
      # @param opts [Hash]
      # @option opts [Integer] :offset
      # @option opts [Integer] :column_separator_width
      # @return [nil]
      def print_separator(io, opts = {})
        offset = opts.fetch(:offset)
        column_separator_width = opts.fetch(:column_separator_width)
        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
      # @return [TermUtils::Tab::Header]
      attr_accessor :header
      # @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)
        @header = TermUtils::Tab::Header.new(:title => @id.to_s, :align => @align)
      end
      # Validates the column represented by this one.
      # @return [nil]
      # @raise [TermUtils::Tab::TableError]
      def validate
        raise TermUtils::Tab::TableError, "missing column id (nil)" if @id.nil?
        raise TermUtils::Tab::TableError, "missing column index (nil)" if @index.nil?
        raise TermUtils::Tab::TableError, "wrong column index (not integer)" unless @index.is_a? Integer
        raise TermUtils::Tab::TableError, "wrong column index (not >= 0)" if @index < 0
        raise TermUtils::Tab::TableError, "missing column width (nil)" if @width.nil?
        raise TermUtils::Tab::TableError, "wrong column width (not integer)" unless @width.is_a? Integer
        raise TermUtils::Tab::TableError, "wrong column width (not > 0)" if @width <= 0
        raise TermUtils::Tab::TableError, "wrong column align (not :left or :right)" unless %i[left right].index(@align)
        @header.validate
      end
      # Renders a given header.
      # @param val [Object]
      # return [String]
      def render_header(val)
        src = (val.is_a? String) ? val : val.to_s
        TermUtils::Tab.align_cut(src, @header.align, @fixed, @width, @ellipsis)
      end
      # Renders a given value.
      # @param val [Object]
      # return [String]
      def render_data(val)
        src = val
        if val
          if @format.is_a? Proc
            src = @format.call(val)
          elsif @format.is_a? String
            src = @format % val
          end
        end
        src = (src.is_a? String) ? src : src.to_s
        TermUtils::Tab.align_cut(src, @align, @fixed, @width, @ellipsis)
      end
    end
    # Represents a column header.
    class Header
      # @return [String]
      attr_accessor :title
      # @return [Symbol] `:left`, `:right`.
      attr_accessor :align
      # Constructs a new Header.
      # @param opts [Hash]
      # @option opts [String] :title
      # @option opts [Symbol] :align
      def initialize(opts = {})
        @title = opts.fetch(:title)
        @align = opts.fetch(:align, :left)
      end
      # Validates the column represented by this one.
      # @return [nil]
      # @raise [TermUtils::Tab::TableError]
      def validate
        raise TermUtils::Tab::TableError, "missing header title (nil)" if @title.nil?
        raise TermUtils::Tab::TableError, "wrong header align (not :left or :right)" unless %i[left right].index(@align)
      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
      # Prints an empty line.
      def line
        @io.puts ""
      end
      # Prints a header row.
      # @param values [Array<Object>, Hash<Symbol, Object>]
      # @param opts [Hash]
      # @option opts [Integer] :offset
      # @option opts [Integer] :column_separator_width
      # @return [nil]
      def header(values = nil, opts = nil)
        @table.print_header(@io, values, opts ? @options.merge(opts) : @options)
      end
      # Prints a data row.
      # @param values [Array<Object>, Hash<Symbol, Object>]
      # @param opts [Hash]
      # @option opts [Integer] :offset
      # @option opts [Integer] :column_separator_width
      # @return [nil]
      def data(values, opts = nil)
        @table.print_data(@io, values, opts ? @options.merge(opts) : @options)
      end
      # Prints a separator.
      # @param opts [Hash]
      # @option opts [Integer] :offset
      # @option opts [Integer] :column_separator_width
      # @return [nil]
      def separator(opts = nil)
        @table.print_separator(@io, opts ? @options.merge(opts) : @options)
      end
    end
    # Represents a holder of tables.
    class Holder
      # @return [Hash] `:offset`, `:column_separator_width`.
      attr_accessor :table_defaults
      # @return [Hash] `:width`, `:align`, `:fixed`, `:ellipsis`, `:format`.
      attr_accessor :column_defaults
      # @return [Hash<Symbol, Tab::Table>]
      attr_accessor :tables
      def initialize(opts = {})
        @table_defaults = TermUtils::Tab.init_table_props
        @column_defaults = TermUtils::Tab.init_column_props
        @tables = {}
      end
      # Sets table default properties.
      # @param opts [Hash]
      # @option opts [Integer] :offset
      # @option opts [Symbol] :column_separator_width
      def set_table_defaults(opts = {})
        TermUtils::Tab.assign_table_props(@table_defaults, opts)
      end
      # Sets column default properties.
      # @param opts [Hash]
      # @option opts [Integer] :width
      # @option opts [Symbol] :align
      # @option opts [Boolean] :fixed
      # @option opts [String] :ellipsis
      # @option opts [Proc, String, nil] :format
      def set_column_defaults(opts = {})
        TermUtils::Tab.assign_column_props(@column_defaults, opts)
      end
      # Creates a new table, using default properties, without registering it.
      # @param opts [Hash]
      # @return [Tab::Table]
      def create_table(opts = {}, &block)
        opts[:offset] = @table_defaults.fetch(:offset)
        opts[:column_separator_width] = @table_defaults.fetch(:column_separator_width)
        opts[:column_defaults] = @column_defaults.dup
        new_tab = Table.new(opts)
        block.call(new_tab) if block
        new_tab
      end
      # Defines a table, using default properties.
      # @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
          opts[:offset] = @table_defaults.fetch(:offset)
          opts[:column_separator_width] = @table_defaults.fetch(:column_separator_width)
          opts[:column_defaults] = @column_defaults.dup
          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 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
    # Sets table default properties.
    # @param opts [Hash]
    # @option opts [Integer] :offset
    # @option opts [Symbol] :column_separator_width
    def self.set_table_defaults(opts = {})
      @@default_holder.set_table_defaults(opts)
    end
    # Sets column default properties.
    # @param opts [Hash]
    # @option opts [Integer] :width
    # @option opts [Symbol] :align
    # @option opts [Boolean] :fixed
    # @option opts [String] :ellipsis
    # @option opts [Proc, String, nil] :format
    def self.set_column_defaults(opts = {})
      @@default_holder.set_column_defaults(opts)
    end
    # Creates a new Table, using default properties, without registering it.
    # @param opts [Hash]
    # @return [Tab::Table]
    def self.create_table(opts = {}, &block)
      @@default_holder.create_table(opts, &block)
    end
    # Defines a new Table, using default properties, and registers it.
    # @param id [Symbol]
    # @param opts [Hash]
    # @return [Tab::Table]
    def self.define_table(id, opts = {}, &block)
      @@default_holder.define_table(id, opts, &block)
    end
    # Finds a registered table.
    # @param id [Symbol]
    # @return [Tab::Table, nil]
    def self.find_table(id)
      @@default_holder.find_table(id)
    end
    # Creates a new Printer for a registered Table.
    # @param id [Symbol]
    # @param io [IO]
    # @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