# Copyright (c) 2014-2015 VMware, Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

require "nokogiri"
require "test/unit"

class Peek
  class Type
    attr_accessor :parent, :children, :klass

    def initialize(name)
      @name = name
      @children = []
    end

    def base?
      return !children.empty?
    end
  end

  @@types = {}
  @@refs = {}
  @@enums = {}

  def self.types
    return @@types
  end

  def self.refs
    return @@refs
  end

  def self.enums
    return @@enums
  end

  def self.ref(type)
    refs[type] = true
  end

  def self.enum(type)
    enums[type] = true
  end

  def self.enum?(type)
    enums[type]
  end

  def self.register(name)
    raise unless name
    types[name] ||= Type.new(name)
  end

  def self.base?(name)
    return unless c = types[name]
    c.base?
  end

  def self.dump_interfaces(io)
    types.keys.sort.each do |name|
      next unless base?(name)

      types[name].klass.dump_interface(io, name)
    end
  end
end

class EnumValue
  def initialize(type, value)
    @type = type
    @value = value
  end

  def type_name
    @type.name
  end

  def var_name
    n = @type.name
    v = var_value
    if v == ""
      n += "Null"
    else
      n += (v[0].capitalize + v[1..-1])
    end

    return n
  end

  def var_value
    @value
  end

  def dump(io)
    io.print "%s = %s(\"%s\")\n" % [var_name, type_name, var_value]
  end
end

class Simple
  include Test::Unit::Assertions

  attr_accessor :name, :type

  def initialize(node)
    @node = node
  end

  def name
    @name || @node["name"]
  end

  def type
    @type || @node["type"]
  end

  def is_enum?
    false
  end

  def dump_init(io)
    # noop
  end

  def var_name
    n = self.name
    n = n[1..-1] if n[0] == "_" # Strip leading _
    n = n[0].capitalize + n[1..-1] # Capitalize
    return n
  end

  def vim_type?
    ns, _ = self.type.split(":", 2)
    ns == "vim25"
  end

  def vim_type(t = self.type)
    ns, t = t.split(":", 2)
    raise if ns != "vim25"
    t
  end

  def base_type?
    vim_type? && Peek.base?(vim_type)
  end

  def enum_type?
    vim_type? && Peek.enum?(vim_type)
  end

  def any_type?
    self.type == "xsd:anyType"
  end

  def var_type
    t = self.type
    prefix = ""

    prefix += "[]" if slice?

    if t =~ /^xsd:(.*)$/
      t = $1
      case t
      when "string"
      when "int"
      when "boolean"
        t = "bool"
        if !slice? && optional?
          prefix += "*"
          self.need_omitempty = false
        end
      when "long"
        t = "int64"
      when "dateTime"
        t = "time.Time"
        if !slice? && optional?
          prefix += "*"
          self.need_omitempty = false
        end
      when "anyType"
        t = "AnyType"
      when "byte"
      when "double"
        t = "float64"
      when "float"
        t = "float32"
      when "short"
        t = "int16"
      when "base64Binary"
        t = "[]byte"
      when "anyURI"
        t = "url.URL"
      else
        raise "unknown type: %s" % t
      end
    else
      t = vim_type
      if base_type?
        prefix += "Base"
      else
        prefix += "*" if !slice? && !enum_type? && optional?
      end
    end

    prefix + t
  end

  def slice?
    test_attr("maxOccurs", "unbounded")
  end

  def optional?
    test_attr("minOccurs", "0")
  end

  def need_omitempty=(v)
    @need_omitempty = v
  end

  def need_omitempty?
    var_type # HACK: trigger setting need_omitempty if necessary
    if @need_omitempty.nil?
      @need_omitempty = optional?
    else
      @need_omitempty
    end
  end

  def need_typeattr?
    base_type? || any_type?
  end

  protected

  def test_attr(attr, expected)
    actual = @node.attr(attr)
    if actual != nil
      case actual
      when expected
        true
      else
        raise "%s=%s" % [value, type.attr(value)]
      end
    else
      false
    end
  end
end

class Element < Simple
  def initialize(node)
    super(node)
  end

  def has_type?
    !@node["type"].nil?
  end

  def child
    cs = @node.element_children
    assert_equal 1, cs.length
    assert_equal "complexType", cs.first.name

    t = ComplexType.new(cs.first)
    t.name = self.name
    t
  end

  def dump(io)
    if has_type?
      io.print "type %s %s\n\n" % [name, var_type]
    else
      child.dump(io)
    end
  end

  def dump_init(io)
    if has_type?
      io.print "func init() {\n"
      io.print "t[\"%s\"] = reflect.TypeOf((*%s)(nil)).Elem()\n" % [name, name]
      io.print "}\n\n"
    end
  end

  def dump_field(io)
    tag = name
    tag += ",omitempty" if need_omitempty?
    tag += ",typeattr" if need_typeattr?
    io.print "%s %s `xml:\"%s\"`\n" % [var_name, var_type, tag]
  end

  def peek(type=nil)
    if has_type?
      return if self.type =~ /^xsd:/

      Peek.ref(vim_type)
    else
      child.peek()
    end
  end
end

class Attribute < Simple
  def dump_field(io)
    tag = name
    tag += ",omitempty" if need_omitempty?
    tag += ",attr"
    io.print "%s %s `xml:\"%s\"`\n" % [var_name, var_type, tag]
  end
end

class SimpleType < Simple
  def is_enum?
    true
  end

  def dump(io)
    enums = @node.xpath(".//xsd:enumeration").map do |n|
      EnumValue.new(self, n["value"])
    end

    io.print "type %s string\n\n" % name
    io.print "const (\n"
    enums.each { |e| e.dump(io) }
    io.print ")\n\n"
  end

  def dump_init(io)
    io.print "func init() {\n"
    io.print "t[\"%s\"] = reflect.TypeOf((*%s)(nil)).Elem()\n" % [name, name]
    io.print "}\n\n"
  end

  def peek
    Peek.enum(name)
  end
end

class ComplexType < Simple
  class SimpleContent < Simple
    def dump(io)
      attr = Attribute.new(@node.at_xpath(".//xsd:attribute"))
      attr.dump_field(io)

      # HACK DELUXE(PN)
      extension = @node.at_xpath(".//xsd:extension")
      type = extension["base"].split(":", 2)[1]
      io.print "Value %s `xml:\",chardata\"`\n" % type
    end

    def peek
    end
  end

  class ComplexContent < Simple
    def base
      extension = @node.at_xpath(".//xsd:extension")
      assert_not_nil extension

      base = extension["base"]
      assert_not_nil base

      vim_type(base)
    end

    def dump(io)
      Sequence.new(@node).dump(io, base)
    end

    def dump_interface(io, name)
      Sequence.new(@node).dump_interface(io, name)
    end

    def peek
      Sequence.new(@node).peek(base)
    end
  end

  class Sequence < Simple
    def sequence
      sequence = @node.at_xpath(".//xsd:sequence")
      if sequence != nil
        sequence.element_children.map do |n|
          Element.new(n)
        end
      else
        nil
      end
    end

    def dump(io, base = nil)
      return unless elements = sequence

      io.print "%s\n\n" % base

      elements.each do |e|
        e.dump_field(io)
      end
    end

    def dump_interface(io, name)
      method = "Get%s() *%s" % [name, name]
      io.print "func (b *%s) %s { return b }\n" % [name, method]
      io.print "type Base%s interface {\n" % name
      io.print "%s\n" % method
      io.print "}\n\n"
      io.print "func init() {\n"
      io.print "t[\"Base%s\"] = reflect.TypeOf((*%s)(nil)).Elem()\n" % [name, name]
      io.print "}\n\n"
    end

    def peek(base = nil)
      return unless elements = sequence
      name = @node.attr("name")
      return unless name

      elements.each do |e|
        e.peek(name)
      end

      c = Peek.register(name)
      if base
        c.parent = base
        Peek.register(c.parent).children << name
      end
    end
  end

  def klass
    @klass ||= begin
                 cs = @node.element_children
                 if !cs.empty?
                   assert_equal 1, cs.length

                   case cs.first.name
                   when "simpleContent"
                     SimpleContent.new(@node)
                   when "complexContent"
                     ComplexContent.new(@node)
                   when "sequence"
                     Sequence.new(@node)
                   else
                     raise "don't know what to do for element: %s..." % cs.first.name
                   end
                 end
               end
  end

  def dump_init(io)
    io.print "func init() {\n"
    io.print "t[\"%s\"] = reflect.TypeOf((*%s)(nil)).Elem()\n" % [name, name]
    io.print "}\n\n"
  end

  def dump(io)
    io.print "type %s struct {\n" % name
    klass.dump(io) if klass
    io.print "}\n\n"
  end

  def peek
    Peek.register(name).klass = klass
    klass.peek if klass
  end
end

class Schema
  include Test::Unit::Assertions

  def initialize(xml, parent = nil)
    @xml = Nokogiri::XML.parse(xml)
  end

  def targetNamespace
    @xml.root["targetNamespace"]
  end

  # We have some assumptions about structure, make sure they hold.
  def validate_assumptions!
    # Every enumeration is part of a restriction
    @xml.xpath(".//xsd:enumeration").each do |n|
      assert_equal "restriction", n.parent.name
    end

    # See type == enum
    @xml.xpath(".//xsd:restriction").each do |n|
      # Every restriction has type xsd:string (it's an enum)
      assert_equal "xsd:string", n["base"]

      # Every restriction is part of a simpleType
      assert_equal "simpleType", n.parent.name

      # Every restriction is alone
      assert_equal 1, n.parent.element_children.size
    end

    # See type == complex_content
    @xml.xpath(".//xsd:complexContent").each do |n|
      # complexContent is child of complexType
      assert_equal "complexType", n.parent.name

    end

    # See type == complex_type
    @xml.xpath(".//xsd:complexType").each do |n|
      cc = n.element_children

      # OK to have an empty complexType
      next if cc.size == 0

      # Require 1 element otherwise
      assert_equal 1, cc.size

      case cc.first.name
      when "complexContent"
        # complexContent has 1 "extension" element
        cc = cc.first.element_children
        assert_equal 1, cc.size
        assert_equal "extension", cc.first.name

        # extension has 1 "sequence" element
        ec = cc.first.element_children
        assert_equal 1, ec.size
        assert_equal "sequence", ec.first.name

        # sequence has N "element" elements
        sc = ec.first.element_children
        assert sc.all? { |e| e.name == "element" }
      when "simpleContent"
        # simpleContent has 1 "extension" element
        cc = cc.first.element_children
        assert_equal 1, cc.size
        assert_equal "extension", cc.first.name

        # extension has 1 or more "attribute" elements
        ec = cc.first.element_children
        assert_not_equal 0, ec.size
        assert_equal "attribute", ec.first.name
      when "sequence"
        # sequence has N "element" elements
        sc = cc.first.element_children
        assert sc.all? { |e| e.name == "element" }
      else
        raise "unknown element: %s" % cc.first.name
      end
    end

    includes.each do |i|
      i.validate_assumptions!
    end
  end

  def types
    return to_enum(:types) unless block_given?

    includes.each do |i|
      i.types do |t|
        yield t
      end
    end

    @xml.root.children.each do |n|
      case n.class.to_s
      when "Nokogiri::XML::Text"
        next
      when "Nokogiri::XML::Element"
        case n.name
        when "include", "import"
          next
        when "element"
          yield Element.new(n)
        when "simpleType"
          yield SimpleType.new(n)
        when "complexType"
          yield ComplexType.new(n)
        else
          raise "unknown child: %s" % n.name
        end
      else
        raise "unknown type: %s" % n.class
      end
    end
  end

  def includes
    @includes ||= @xml.root.xpath(".//xmlns:include").map do |n|
      Schema.new(WSDL.read n["schemaLocation"])
    end
  end
end


class Operation
  include Test::Unit::Assertions

  def initialize(wsdl, operation_node)
    @wsdl = wsdl
    @operation_node = operation_node
  end

  def name
    @operation_node["name"]
  end

  def remove_ns(x)
    ns, x = x.split(":", 2)
    assert_equal "vim25", ns
    x
  end

  def find_type_for(type)
    type = remove_ns(type)

    message = @wsdl.message(type)
    assert_not_nil message

    part = message.at_xpath("./xmlns:part")
    assert_not_nil message

    remove_ns(part["element"])
  end

  def input
    type = @operation_node.at_xpath("./xmlns:input").attr("message")
    find_type_for(type)
  end

  def go_input
    "types." + input
  end

  def output
    type = @operation_node.at_xpath("./xmlns:output").attr("message")
    find_type_for(type)
  end

  def go_output
    "types." + output
  end

  def dump(io)
    io.print <<EOS
  type #{name}Body struct{
    Req *#{go_input} `xml:"urn:vim25 #{input},omitempty"`
    Res *#{go_output} `xml:"urn:vim25 #{output},omitempty"`
    Fault_ *soap.Fault `xml:"http://schemas.xmlsoap.org/soap/envelope/ Fault,omitempty"`
  }

  func (b *#{name}Body) Fault() *soap.Fault { return b.Fault_ }

EOS

    io.print "func %s(ctx context.Context, r soap.RoundTripper, req *%s) (*%s, error) {\n" % [name, go_input, go_output]
    io.print <<EOS
  var reqBody, resBody #{name}Body

  reqBody.Req = req

  if err := r.RoundTrip(ctx, &reqBody, &resBody); err != nil {
    return nil, err
  }

  return resBody.Res, nil
EOS

    io.print "}\n\n"
  end
end

class WSDL
  attr_reader :xml

  PATH = File.expand_path("../sdk", __FILE__)

  def self.read(file)
    File.open(File.join(PATH, file))
  end

  def initialize(xml)
    @xml = Nokogiri::XML.parse(xml)
  end

  def validate_assumptions!
    schemas.each do |s|
      s.validate_assumptions!
    end
  end

  def types(&blk)
    return to_enum(:types) unless block_given?

    schemas.each do |s|
      s.types(&blk)
    end
  end

  def schemas
    @schemas ||= @xml.xpath('.//xmlns:types/xsd:schema').map do |n|
      Schema.new(n.to_xml)
    end
  end

  def operations
    @operations ||= @xml.xpath('.//xmlns:portType/xmlns:operation').map do |o|
      Operation.new(self, o)
    end
  end

  def message(type)
    @messages ||= begin
                    h = {}
                    @xml.xpath('.//xmlns:message').each do |n|
                      h[n.attr("name")] = n
                    end
                    h
                  end

    @messages[type]
  end

  def peek
    types.
      sort_by { |x| x.name }.
      uniq { |x| x.name }.
      select { |x| x.name[0] == x.name[0].upcase }. # Only capitalized methods for now...
      each { |e| e.peek() }
  end

  def self.header(name)
    return <<EOF
package #{name}

EOF
  end
end