require 'hamlit/attribute_builder'
require 'hamlit/attribute_parser'
require 'hamlit/ruby_expression'
require 'hamlit/static_analyzer'

module Hamlit
  class AttributeCompiler
    def initialize(identity, options)
      @identity = identity
      @quote  = options[:attr_quote]
      @format = options[:format]
      @escape_attrs = options[:escape_attrs]
    end

    def compile(node)
      hashes = []
      return runtime_compile(node) if node.value[:object_ref] != :nil
      node.value[:attributes_hashes].each do |attribute_str|
        hash = AttributeParser.parse(attribute_str)
        return runtime_compile(node) unless hash
        hashes << hash
      end
      static_compile(node.value[:attributes], hashes)
    end

    private

    def runtime_compile(node)
      attrs = node.value[:attributes_hashes]
      attrs.unshift(node.value[:attributes].inspect) if node.value[:attributes] != {}

      args = [@escape_attrs, @quote, @format].map(&:inspect).push(node.value[:object_ref]) + attrs
      [:html, :attrs, [:dynamic, "::Hamlit::AttributeBuilder.build(#{args.join(', ')})"]]
    end

    def static_compile(static_hash, dynamic_hashes)
      temple = [:html, :attrs]
      keys = [*static_hash.keys, *dynamic_hashes.map(&:keys).flatten].uniq.sort
      keys.each do |key|
        values = [[:static, static_hash[key]], *dynamic_hashes.map { |h| [:dynamic, h[key]] }]
        values.select! { |_, exp| exp != nil }

        case key
        when 'id'.freeze
          compile_id!(temple, key, values)
        when 'class'.freeze
          compile_class!(temple, key, values)
        when 'data'.freeze
          compile_data!(temple, key, values)
        when *AttributeBuilder::BOOLEAN_ATTRIBUTES, /\Adata-/
          compile_boolean!(temple, key, values)
        else
          compile_common!(temple, key, values)
        end
      end
      temple
    end

    def compile_id!(temple, key, values)
      build_code = attribute_builder(:id, values)
      if values.all? { |type, exp| type == :static || StaticAnalyzer.static?(exp) }
        temple << [:html, :attr, key, [:static, eval(build_code).to_s]]
      else
        temple << [:html, :attr, key, [:dynamic, build_code]]
      end
    end

    def compile_class!(temple, key, values)
      build_code = attribute_builder(:class, values)
      if values.all? { |type, exp| type == :static || StaticAnalyzer.static?(exp) }
        temple << [:html, :attr, key, [:static, eval(build_code).to_s]]
      else
        temple << [:html, :attr, key, [:dynamic, build_code]]
      end
    end

    def compile_data!(temple, key, values)
      args = [@escape_attrs.inspect, @quote.inspect, values.map { |v| literal_for(v) }]
      build_code = "::Hamlit::AttributeBuilder.build_data(#{args.join(', ')})"

      if values.all? { |type, exp| type == :static || StaticAnalyzer.static?(exp) }
        temple << [:static, eval(build_code).to_s]
      else
        temple << [:dynamic, build_code]
      end
    end

    def compile_boolean!(temple, key, values)
      exp = literal_for(values.last)

      if StaticAnalyzer.static?(exp)
        value = eval(exp)
        case value
        when true then temple << [:html, :attr, key, @format == :xhtml ? [:static, key] : [:multi]]
        when false, nil
        else temple << [:html, :attr, key, [:escape, @escape_attrs, [:static, value.to_s]]]
        end
      else
        var = @identity.generate
        temple << [
          :case, "(#{var} = (#{exp}))",
          ['true', [:html, :attr, key, @format == :xhtml ? [:static, key] : [:multi]]],
          ['false, nil', [:multi]],
          [:else, [:multi, [:static, " #{key}=#{@quote}"], [:escape, @escape_attrs, [:dynamic, var]], [:static, @quote]]],
        ]
      end
    end

    def compile_common!(temple, key, values)
      temple << [:html, :attr, key, [:escape, @escape_attrs, values.last]]
    end

    def attribute_builder(type, values)
      args = [@escape_attrs.inspect, *values.map { |v| literal_for(v) }]
      "::Hamlit::AttributeBuilder.build_#{type}(#{args.join(', ')})"
    end

    def literal_for(value)
      type, exp = value
      type == :static ? exp.inspect : exp
    end
  end
end