require 'erb'

require_relative '../builder'
require_relative './javascript_templates'

module Shift
	module Generator

		class JavaScriptGenerator
			attr_accessor :blocks, :functions, :builder, :url_variables, :has_models, :defined_hashes

			def initialize()
				@blocks = []
				@defined_hashes = []
				@functions = []
				@has_models = false
				@builder = Shift::ShiftBuilder.new
			end
			
			def get_data(builder)
				@builder = builder
			end

			def get_data_from_file(file_name)
				@builder.get_data_from_file file_name
			end

			def get_import_statements()
				Shift::Generator::JavaScriptTemplates::IMPORT_JQNODE_STATEMENT + 
				Shift::Generator::JavaScriptTemplates::IMPORT_UTIL_STATEMENT + 
				Shift::Generator::JavaScriptTemplates::IMPORT_MU_STATEMENT + 
				(@has_models ? Shift::Generator::JavaScriptTemplates::IMPORT_DB_STATEMENT : "") + 
				Shift::Generator::JavaScriptTemplates::UTILITY_FUNCTIONS + "\n"
			end

			def get_model_data()
				result = ""

				model_name_template = ERB.new(Shift::Generator::JavaScriptTemplates::MODEL_NAME_TEMPLATE)

				@builder.models.each do | model |
					model_name = model.name
					result += model_name_template.result(binding) + "\n"

					first = true

					# TODO: Test if comma syntax is valid

					model.attributes.each do | attribute |
						if (attribute[:type] == "string")
							if (first == true)
								first = false
							else
								result += ","
							end
							result += ("\t" + attribute[:name] + " : " + "String" + "\n") 
						else
							if (attribute[:type] == "integer")
								if (first == true)
									first = false
								else
									result += ","
								end						
								result += ("\t" + attribute[:name] + " : " + "Number" + "\n")	
							end
						end
					end

					result += "});\n\n"
				end

				result
			end

			def url_transform(url) 
				if(url.is_a?(Array))
					result_url = ""
					
					url.each do | token |
						case token.keys[0]
						when :url_token
							result_url += "/" + token[:url_token].to_s
						when :url_variable
							result_url += "/:" + token[:url_variable].to_s
						end			
					end
					result_url
				else
					url.to_s
				end
			end	

			def expression_transform(statement, num_tabs)
				tabs = ""
				num_tabs.times { tabs += "\t" }
				key = statement.keys[0]
				case key
				when :assignment_statement
					extra = ""
					if(statement[:assignment_statement][:left].keys[0] == :hash_value)
						val = statement[:assignment_statement][:left][:hash_value].to_s
						hash_var = val[0..(val.index('[') - 1)]
						if !@defined_hashes.include?(hash_var)
							@defined_hashes.push hash_var
							extra += (tabs + "if (typeof " + hash_var + " == 'undefined')\n")
							extra += (tabs + "\t" + hash_var + " = {}\n")
						end
					end
					
					left = apply_transforms(statement[:assignment_statement][:left], 0) 
					right = apply_transforms(statement[:assignment_statement][:right], 0) 

					if(statement[:assignment_statement][:left].keys[0] == :object_value)
						value_name = statement[:assignment_statement][:left][:object_value].to_s
						value_name = value_name[(value_name.index('.') + 1)..(value_name.length - 1)]
					end

					if(statement[:assignment_statement][:right].is_a?(Hash) && statement[:assignment_statement][:right].keys[0] == :query)
						case statement[:assignment_statement][:right][:query][:operation]
						when "all"
							@functions.push (tabs + "});")
							tabs + right.to_s + left.to_s + ") {"
						when "new"
							tabs + "var " + left.to_s + " = " + right.to_s
						when "find"
							@functions.push (tabs + "});")
							tabs + right.to_s + left.to_s + ") {"
						when "find_by_id"
							@functions.push (tabs + "});")
							tabs + right.to_s + left.to_s + ") {"
						end
					else 
						extra + tabs + left.to_s + " = " + right.to_s + ";"
					end			
				else
					""
				end
			end

			def token_transform(statement, num_tabs)
				tabs = ""
				num_tabs.times { tabs += "\t" }

					key = statement.keys[0]

				case key
				when :identifier
					result = statement[:identifier].to_s 
					@url_variables.include?(result) ? "urlData['" + result + "']" : result
				when :object_value 
					if (statement[:object_value].to_s.split(".")[1] == "save")
						tabs + statement[:object_value].to_s.split(".")[0] + ".save();" + "\n"
					else
						tabs + statement[:object_value].to_s
					end
				when :hash_value
					statement[:hash_value].to_s
				when :string
					statement[:string].to_s
				else
					""
				end

			end

			def write_function_transform(statement, num_tabs)
				tabs = ""
				num_tabs.times { tabs += "\t" }

				write_data_template = ERB.new(Shift::Generator::JavaScriptTemplates::WRITE_DATA_TEMPLATE)

				write_data = apply_transforms(statement[:write_statement][:write_statement_param], 0)

				tabs + write_data_template.result(binding)
			end

			def write_file_function_transform(statement, num_tabs)
				tabs = ""
				num_tabs.times { tabs += "\t" }
				
				write_file_template = ERB.new(Shift::Generator::JavaScriptTemplates::WRITE_FILE_TEMPLATE)
				
				if(statement[:write_file_statement].is_a?(Array))
					file_name = apply_transforms(statement[:write_file_statement][0][:file_name], 0)
					template_values = apply_transforms(statement[:write_file_statement][1][:template_values], 0)
					args = file_name + ', ' + template_values + ", response"
				else
					file_name = apply_transforms(statement[:write_file_statement][:file_name], 0)
					args = file_name + ', false'
				end		

				tabs + write_file_template.result(binding)
			end


			def query_transform(statement, num_tabs)
				tabs = ""
				num_tabs.times { tabs += "\t" }
				statement = statement[:query]
				case statement[:operation].to_s
				when "all"		
					statement[:model_name].to_s + ".all(function (err, "
				when "new"
					(statement[:model_name].to_s + "()")
				when "find"
					result = statement[:model_name].to_s + ".all({ where : "
					condition = statement[:condition]				
					
					condition_attribute = apply_transforms(condition[:value], 0)

					condition_expression = ""

					case statement[:condition][:operator].to_s.gsub!(" ", "")
					when "<="
						condition_expression = "{lte : " + condition_attribute + "}"
					when ">="
						condition_expression = "{gte : " + condition_attribute + "}"
					when "<"
						condition_expression = "{lt : " + condition_attribute + "}"
					when ">"
						condition_expression = "{gt : " + condition_attribute + "}"
					when "!="
						condition_expression = "{not : " + condition_attribute + "}"						
					else
						condition_expression = condition_attribute
					end
					
					result += "{ " + condition[:attribute] + " : " + condition_expression + " }"
					result += " }, function (err, "
				when "find_by_id"
					result = statement[:model_name].to_s + ".find("
					result += apply_transforms(statement[:item_id], 0)
					result += ", function(err, "
				when "update"
					@functions.push (tabs + "});")
					result = tabs + statement[:model_name].to_s + ".updateAttributes({}, function() {"				
				when "delete"
					@functions.push (tabs + "});")
					result = tabs + statement[:model_name].to_s + ".destroy(function() {"				
				end
			end

			def read_statement_transform(statement, num_tabs)
				param = apply_transforms(statement[:read_statement][:read_statement_param], 0)
				"data[" + param + "]"
			end

			def redirect_statement_transform(statement, num_tabs)
				tabs = ""
				num_tabs.times { tabs += "\t" }

				redirect_statement_template = ERB.new(Shift::Generator::JavaScriptTemplates::REDIRECT_STATEMENT_TEMPLATE)
				url = apply_transforms(statement[:redirect_statement][:redirect_statement_param], 0)
				"\n" + tabs + redirect_statement_template.result(binding)
			end

			def value_transform(statement, num_tabs)
				tabs = ""
				num_tabs.times { tabs += "\t" }

				key = statement.keys[0]

				statement[key].to_s
			end

			def control_statement_transform(statement, num_tabs)
				tabs = ""
				num_tabs.times { tabs += "\t" }

				key = statement.keys[0]

				result = ""

				@blocks.push (num_tabs)

				case key
				when :if_statement
					result = tabs + "if " + apply_transforms(statement[:if_statement][:condition], 0) + " {"
				when :while_statement
					result = tabs + "while " + apply_transforms(statement[:while_statement][:condition], 0) + " {"			
				end			

				result
			end
			
			def concatenated_string_expression_transform(statement, num_tabs)
				statement = statement.map do | token |
					apply_transforms(token, 0)
				end

				statement.join(" + ")
			end

			def integer_casted_expression_transform(statement, num_tabs)
				statement.delete(:int)
				"Number(" + apply_transforms(statement, 0) + ")"
			end

			def apply_transforms(statement, num_tabs)
				tabs = ""
				if (num_tabs > 0)
					num_tabs = num_tabs - 1
				end

				result = ""

				if(@blocks.length > 0)
					if(@blocks[@blocks.length - 1] == num_tabs)
						t = ""
						@blocks.pop.times { t += "\t" }
						result += t + "}\n"
					end
				end		

				num_tabs.times { tabs += "\t" }

				if(statement.is_a?(Hash))
					key = statement.keys[0]
					case key
					when :assignment_statement
						result += expression_transform(statement, num_tabs) + "\n"
					when :write_statement
						result += write_function_transform(statement, num_tabs) + "\n"	
					when :write_file_statement
						result += write_file_function_transform(statement, num_tabs) + "\n"
					when :read_statement
						result += read_statement_transform(statement, num_tabs)
					when :redirect_statement
						result += redirect_statement_transform(statement, num_tabs) + "\n"
					when :arithmetic_expression
						result += value_transform(statement, num_tabs)
					when :boolean_expression
						result += value_transform(statement, num_tabs)
					when :if_statement
						result += control_statement_transform(statement, num_tabs) + "\n"
					when :else_statement
						@blocks.push (num_tabs)
						result += tabs + value_transform(statement, num_tabs) + " {\n"
					when :for_statement
						statement = statement[:for_statement]
						tokens = statement.to_s.split(" ")
						@blocks.push (num_tabs)
						result += tabs + "for(var k in " + tokens[3] + ") {\n" 						
						result += tabs + "\t" + tokens[1] + " = " + tokens[3] + "[k];\n"
					when :while_statement
						result += control_statement_transform(statement, num_tabs) + "\n"								
					when :query
						result += query_transform(statement, num_tabs)
					when :int
						integer_casted_expression_transform(statement, num_tabs)
					else
						result += token_transform(statement, num_tabs)	
					end
				else
					if statement.is_a?(Array)
						concatenated_string_expression_transform(statement, num_tabs)
					else
						result += statement.to_s
					end
				end
			end

			def write_data()
				if(@builder.models.length != 0)
					@has_models = true
				end

				result = get_import_statements + get_model_data

				@builder.handlers.each do | handlers |
					url = url_transform(handlers.url)
					method = handlers.method

					@url_variables = []
					current_url = handlers.url
					if(current_url.is_a?(Array))
						current_url.each do | token |
							case token.keys[0]
							when :url_variable
								@url_variables.push token[:url_variable]
							end
						end
					end

					url_handler_template = ERB.new(Shift::Generator::JavaScriptTemplates::URL_HANDLER_DEFINITION)
					result += "\n" + url_handler_template.result(binding) + "\n"

					@defined_hashes = []

					handlers.handler.each do | statement |
						result += apply_transforms(statement[:statement], statement[:num_tabs] + functions.length) 
					end

					i = @functions.length - 2

					blocks.each do | t |
						tabs = ""
						t.times { tabs += "\t" }
						result += tabs + "}" + "\n"
					end

					functions.reverse.each do | closing_block |
						tabs = ""
						i.times { tabs += "\t" }
						result += tabs + closing_block + "\n"
					end

					@functions = []
					@blocks = []

					result += "});\n"
				end

				result += "\n\n" + Shift::Generator::JavaScriptTemplates::APP_START_STATEMENT
			end
		end
	end
end