require 'set'
require 'ostruct'
require 'yaml'
require 'pathname'
require 'base64'

require 'aws/with-stacco-patches'

require 'stacco/base'

require 'stacco/template/old'

class Stacco::Stack
  def initialize(stack_bucket)
    @bucket = stack_bucket
    @bucket.cache_dir = Pathname.new(ENV['HOME']) + '.config' + 'stacco' + 'stack' + @bucket.name

    @config_object = @bucket.objects['stack.yml']

    aws_creds = self.aws_credentials
    @services = {
      ec2: AWS::EC2.new(aws_creds),
      s3: AWS::S3.new(aws_creds),
      autoscaling: AWS::AutoScaling.new(aws_creds),
      route53: AWS::Route53.new(aws_creds),
      cloudformation: AWS::CloudFormation.new(aws_creds),
      cloudfront: AWS::CloudFront.new(aws_creds),
      iam: AWS::IAM.new(aws_creds)
    }

    @aws_stack = @services[:cloudformation].stacks[self.name]
    @aws_stack.service_registry = @services
  end

  def connections
    connections = {}
    @aws_stack.instances.each{ |i| connections[i.tags["aws:cloudformation:logical-id"]] = i }
    connections
  end

  def resource_summaries
    @aws_stack.resource_summaries
  end

  def must_be_up!
    unless self.up?
      $stderr.puts "stack #{self.name} is down"
      Kernel.exit 1
    end
  end

  def operation_in_progress?
    @aws_stack.exists? and @aws_stack.status =~ /_IN_PROGRESS$/
  end

  def cancel_operation
    return unless self.operation_in_progress?
    @aws_stack.cancel_update
  end

  def cancel_operation!
    self.cancel_operation
    Kernel.sleep(2) while self.operation_in_progress?
  end

  def aws_status
    @aws_stack.status
  end

  def status
    self.up? ? self.aws_status : "DOWN"
  end

  def domain
    domain = Stacco::Domain.new(self, self.config['domain'].gsub(/\.$/, '').split('.').reverse)
    domain.service_registry = @services
    domain
  end

  def subdomains
    d = self.domain

    self.config['subdomains'].map do |logical_name, prefix_parts|
      sd = prefix_parts.inject(d, &:+)
      sd.logical_name = logical_name
      sd
    end
  end

  def config
    YAML.load(@config_object.read)
  end

  def config=(new_config)
    @config_object.write(new_config.to_yaml)
  end

  def update_config
    new_config = self.config
    yield(new_config)
    self.config = new_config
  end

  def enable_layers(layer_names)
    layer_names = layer_names.map(&:to_s)
    layer_names.each do |layer_name|
      raise ArgumentError, "Layer '#{layer_name}' is not provided by the template definition" unless self.available_layers.include? layer_name
    end

    self.update_config do |c|
      c['layers'] = self.enabled_layers | layer_names
    end
  end

  def disable_layers(layer_names)
    layer_names = layer_names.map(&:to_s)

    self.update_config do |c|
      c['layers'] = self.enabled_layers - layer_names
    end
  end

  def enabled_layers
    self.available_layers & (self.config['layers'] || [])
  end

  def layer_enabled?(layer_name)
    self.enabled_layers.inlude?(layer_name.to_s)
  end

  def aws_credentials
    Hash[ *(self.config['aws'].map{ |k, v| [k.intern, v] }.flatten) ]
  end

  def description
    self.config['description']
  end

  def name
    self.config['name']
  end

  def name=(new_name)
    update_config do |c|
      c['name'] = new_name
    end
  end

  def up?
    @aws_stack.exists?
  end

  def bake_template(opts = {})
    publish_first = opts.delete(:publish)

    baked_template_body = self.cloudformation_template_body

    env_lns = [
      "cat >/etc/environment.local <<EOF",
      self.config.find_all{ |k, v| v.kind_of?(String) }.map{ |(k, v)| "export #{k.to_s.upcase}=\"#{v}\"" },
      self.secrets.find_all{ |k, v| v.kind_of?(String) }.map{ |k, v| "export #{k.to_s.upcase}=\"#{v}\"" },
      "EOF",
      "source /etc/environment.local"
    ].flatten.map{ |ln| ln + "\n" }

    parameters = {
      'DockerLibrarySnapshotVar' => self.config['docker_library_snapshot'],
      'IAMKeypairNameVar' => self.iam_keypair_name,
      'DBAdminUsernameVar' => self.secrets['db_admin_username'],
      'DBAdminPasswordVar' => self.secrets['db_admin_password'],
      'EnvironmentTypeVar' => self.config['environment'],
      'UserDataEnvironmentVar' => env_lns.join
    }

    Stacco::Resources::RoleScripts.each do |role_name, role_script|
      parameters["#{role_name}RoleScriptVar"] = role_script
    end


    bake_id = '%d-%04x' % [Time.now.to_i, rand(36 ** 4)]
    template_object = @bucket.objects["template/#{bake_id}"]

    if publish_first
      template_object.write(baked_template_body, acl: :authenticated_read)
    end

    return [template_object, parameters] unless block_given?

    if block_given?
      new_template_body = yield(baked_template_body, parameters)
    else
      new_template_body = baked_template_body
    end

    unless publish_first and new_template_body == baked_template_body
      if new_template_body
        template_object.write(new_template_body, acl: :authenticated_read)
      else
        template_object.delete if template_object.exists?
      end
    end

    [template_object, parameters]
  end

  def secrets
    self.config['secrets']
  end

  def roles
    Stacco::Resources::RoleScripts.keys
  end

  def available_layers
    Stacco::Resources::LayerTemplates.keys
  end

  def up!
    body_object, params = self.bake_template(publish: true)

    unless @aws_stack.exists?
      return @services[:cloudformation].stacks.create(
        self.name,
        body_object.public_url,
        parameters: params
      )
      #disable_rollback: true
    end

    begin
      @aws_stack.update(template: body_object.public_url, parameters: params)
      true
    rescue AWS::CloudFormation::Errors::ValidationError => e
      raise unless e.message =~ /no updates/i
      false
    end
  end

  def up_since
    @aws_stack.creation_time if @aws_stack.exists?
  end

  def initialize_distributions!
    @services[:cloudfront].distributions.each do |dist|
      dist.update do
        dist.price_class = :"100"
        dist.certificate = @aws_stack.server_certificates(domain: dist.aliases).first.id
      end
    end
  end

  def down!
    return false unless self.up?

    @aws_stack.buckets.each{ |bucket| bucket.delete! }
    @aws_stack.delete

    true
  end

  def cloudformation_template
    Stacco::Template.const_get(self.config['template']).new
  end

  def cloudformation_template_body
    self.cloudformation_template.to_json(stack: self)
  end

  def validate
    body_object, _ = self.bake_template do |body, params|
      tpl.gsub(/"[cm][123]\.(\dx)?(small|medium|large)"/, '"m1.small"')
    end

    Kernel.sleep 1

    begin
      @services[:cloudformation].estimate_template_cost(body_object)
      [true]
    rescue AWS::CloudFormation::Errors::ValidationError => e
      msg = e.message
      match = msg.scan(/^Template format error: JSON not well-formed. \(line (\d+), column (\d+)\)$/)
      if match.length.nonzero?
        line, column = match.to_a.flatten.map{ |el| el.to_i }
        [false, msg, [baked_template_object.read.split("\n")[line.to_i], column]]
      else
        [false, msg]
      end
    end
  end

  def iam_private_key
    @bucket.objects.with_prefix("ssh-key/").to_a.sort_by{ |obj| obj.key.split('/').last.to_i }.last
  end

  def iam_keypair_name
    "stacco-%s-%s" % [self.name, self.iam_private_key.key.split('/').last]
  end

  def stream_events
    Enumerator.new do |out|
      known_events = Set.new
      ticks_without_add = 0
      current_tick = 0
      current_op = nil
      tracked_resources = Set.new

      while true
        added = 0

        stack_events = @aws_stack.events.to_a rescue []

        current_resources = [@aws_stack.instances, @aws_stack.distributions].flatten
        current_resources.each do |new_rs|
          next if tracked_resources.member? new_rs
          tracked_resources.add new_rs
          new_rs.instance_variable_set('@prev_status', :nonexistent)
        end

        tracked_resources.each do |rs|
          resource_name = [rs.tags['aws:cloudformation:logical-id']]
          if rs.tags['aws:autoscaling:groupName']
            resource_name.push(rs.id.split('-')[1])
          end
          resource_name = resource_name.compact.join('.')

          resource_is_live = (current_tick > 0)
          resource_status_delta = rs.change_in_status

          if resource_is_live and resource_status_delta
            now = Time.now
            evt = OpenStruct.new(
              event_id: "#{rs.id}#{now.to_i}#{resource_status_delta.inspect}",
              live: true,
              logical_resource_id: resource_name,
              status: "CHANGED",
              operation: "UPDATE",
              timestamp: now,
              error: "#{resource_status_delta[:from]} -> #{resource_status_delta[:to]}",
              detail: nil
            )

            if resource_status_delta[:to] == :terminated and rs.respond_to?(:console_output) and logs = rs.console_output
              logs = logs.split("\r\n")
              if cfn_signal_ln = logs.grep("CloudFormation signaled successfully with FAILURE.").last
                logs = logs[0 ... logs.index(cfn_signal_ln)]
              end
              logs = logs[-30 .. -1]
              evt.detail = logs.map{ |ln| ln }
            end

            stack_events.push evt
          end
        end

        stack_events = stack_events.sort_by{ |ev| ev.timestamp }

        stack_events.each do |event|
          next if known_events.include? event.event_id
          known_events.add event.event_id

          if event.resource_type == "AWS::CloudFormation::Stack"
            current_op = event
          end

          event.live = (current_tick > 0)
          event.op = current_op

          out.yield event

          added += 1
          ticks_without_add = 0
        end

        if current_tick == 0 and stack_events.last.op
          stack_events.last.op.live = true
          stack_events.each{ |ev| out.yield(ev) if (ev.op and ev.op.live) }
        end

        current_tick += 1
        ticks_without_add += 1 if added == 0

        if ticks_without_add >= 8 and (Math.log2(ticks_without_add) % 1) == 0.0
          jobs = @aws_stack.resource_summaries
          active_jobs = jobs.find_all{ |job| job[:resource_status] =~ /IN_PROGRESS$/ }.map{ |job| job[:logical_resource_id] }.sort
          unless active_jobs.empty?
            out.yield OpenStruct.new(
              live: true,
              logical_resource_id: "Scheduler",
              status: "WAIT",
              operation: "WAIT",
              timestamp: Time.now,
              error: "waiting on #{active_jobs.join(', ')}",
              detail: nil
            )
          end
        end

        Kernel.sleep 2
      end
    end
  end
end