# typed: false

# Copyright (c) 2015 Sqreen. All Rights Reserved.
# Please refer to our terms for more information: https://www.sqreen.com/terms.html

require 'sqreen/weave/legacy'
require 'sqreen/weave/budget'
require 'sqreen/graft/hook'
require 'sqreen/graft/hook_point'
require 'sqreen/call_countable'
require 'sqreen/rules'
require 'sqreen/rules/record_request_context'
require 'sqreen/sqreen_signed_verifier'

class Sqreen::Weave::Legacy::Instrumentation
  attr_accessor :metrics_engine

  def initialize(metrics_engine, opts = {})
    Sqreen::Weave.logger.debug { "#{self.class.name}#initialize #{metrics_engine}" }
    @hooks = []

    self.metrics_engine = metrics_engine

    ### bail out if no metric engine
    return if metrics_engine.nil?

    ### init metric to count calls to sqreen
    metrics_engine.create_metric(
      'name' => 'sqreen_call_counts',
      'period' => 60,
      'kind' => 'Sum',
    )
    ### init metric to count request whitelist matches (ip or path whitelist)
    metrics_engine.create_metric(
      'name' => 'whitelisted',
      'period' => 60,
      'kind' => 'Sum',
    )
    ### init metric to count over budget hits
    metrics_engine.create_metric(
      'name' => 'request_overtime',
      'period' => 60,
      'kind' => 'Sum',
    )

    # PerformanceNotifications::Binning
    metrics_engine.create_metric(
      'name' => 'req',
      'period' => opts[:period] || 60,
      'kind' => 'Binning',
      'options' => opts[:perf_metric] || { 'base' => 2.0, 'factor' => 0.1 },
    )
    metrics_engine.create_metric(
      'name' => 'sq',
      'period' => opts[:period] || 60,
      'kind' => 'Binning',
      'options' => opts[:perf_metric] || { 'base' => 2.0, 'factor' => 0.1 },
    )
    metrics_engine.create_metric(
      'name' => 'pct',
      'period' => opts[:period] || 60,
      'kind' => 'Binning',
      'options' => opts[:perf_metric_percent] || { 'base' => 1.3, 'factor' => 1.0 },
    )

    metrics_engine.create_metric(
      'name' => 'req.sq.hook.overhead',
      'period' => 60,
      'kind' => 'Binning',
      'options' => { 'base' => 2.0, 'factor' => 0.1 },
    )

    metrics_engine.create_metric(
      'name' => 'sq.hook.overhead',
      'period' => 60,
      'kind' => 'Binning',
      'options' => { 'base' => 2.0, 'factor' => 0.1 },
    )

    metrics_engine.create_metric(
      'name' => 'sq.shrinkwrap',
      'period' => 60,
      'kind' => 'Binning',
      'options' => { 'base' => 2.0, 'factor' => 0.1 },
    )

    Sqreen.thread_cpu_time? && metrics_engine.create_metric(
      'name' => 'sq_thread_cpu_pct',
      'period' => opts[:period] || 60,
      'kind' => 'Binning',
      'options' => opts[:perf_metric_percent] || { 'base' => 1.3, 'factor' => 1.0 },
    )
  end

  # needed by Sqreen::Runner#initialize
  def instrument!(rules, framework)
    Sqreen::Weave.logger.debug { "#{rules.count} rules, #{framework}" }

    strategy = Sqreen.config_get(:weave_strategy)
    if strategy == :prepend && !Module.respond_to?(:prepend)
      Sqreen::Weave.logger.warn { "strategy: #{strategy.inspect} unavailable, falling back to :chain" }
      strategy = :chain
    elsif strategy == :chain && Gem::Specification.select { |s| s.name == 'scout_apm' && Gem::Requirement.new('>= 2.5.2').satisfied_by?(Gem::Version.new(s.version)) }.any?
      Sqreen::Weave.logger.warn { "strategy: #{strategy.inspect} unavailable with scout_apm >= 2.5.2, switching to :prepend" }
      strategy = :prepend
    end
    Sqreen::Weave.logger.debug { "strategy: #{strategy.inspect}" }

    ### set up rule signature verifier
    verifier = nil
    if Sqreen.features['rules_signature'] &&
       Sqreen.config_get(:rules_verify_signature) == true &&
       !defined?(::JRUBY_VERSION)
      verifier = Sqreen::SqreenSignedVerifier.new
      Sqreen::Weave.logger.debug('Rules signature enabled')
    else
      Sqreen::Weave.logger.debug('Rules signature disabled')
    end

    ### force clean instrumentation callback list
    @hooks = []
    ### for each rule description
    rules.each do |rule|
      Sqreen::Weave.logger.debug { "Processing rule: #{rule['name']}" }
      ### transform into format for adding callback
      rule_callback = Sqreen::Rules.cb_from_rule(rule, self, metrics_engine, verifier)
      next unless rule_callback
      ### attach framework to callback
      rule_callback.framework = framework
      ## create metric
      Sqreen::Weave.logger.debug { "Adding rule metric: #{rule_callback}" }
      [:pre, :post, :failing].each do |whence|
        next unless rule_callback.send(:"#{whence}?")
        metric_name = "sq.#{rule['name']}.#{whence}"
        metrics_engine.create_metric(
          'name' => metric_name,
          'period' => 60,
          'kind' => 'Binning',
          'options' => { 'base' => 2.0, 'factor' => 0.1 },
        )
        metric_name = "req.sq.#{rule['name']}.#{whence}"
        metrics_engine.create_metric(
          'name' => metric_name,
          'period' => 60,
          'kind' => 'Binning',
          'options' => { 'base' => 2.0, 'factor' => 0.1 },
        )
      end
      ### install callback, observing priority
      Sqreen::Weave.logger.debug { "Adding rule callback: #{rule_callback}" }
      @hooks << add_callback("weave,rule=#{rule['name']}", rule_callback, strategy)
    end

    ### for each hardcoded callback
    hardcoded_callbacks(framework).each do |hard_callback|
      Sqreen::Weave.logger.debug { "Adding hardcoded callback: #{hard_callback}" }
      ###   install hardcoded callbacks, observing priority
      @hooks << add_callback('weave,hardcoded', hard_callback, strategy)
    end

    metrics_engine = self.metrics_engine

    request_hook = Sqreen::Graft::Hook['Sqreen::ShrinkWrap#call', strategy]
    @hooks << request_hook
    request_hook.add do
      before('wave,meta,request', rank: -100000, mandatory: true) do |_call|
        next unless Sqreen.instrumentation_ready

        # shrinkwrap_timer = Sqreen::Graft::Timer.new('weave,shrinkwrap')
        # shrinkwrap_timer.start

        request_timer = Sqreen::Graft::Timer.new("request")
        request_timer.start
        sqreen_timer = Sqreen::Graft::Timer.new("sqreen")
        budget = Sqreen::Weave::Budget.current
        request_budget_threshold = budget.threshold if budget
        request_budget_ratio = budget.ratio if budget
        request_budget_is_dynamic = !request_budget_ratio.nil?
        request_budget = !request_budget_threshold.nil?
        timed_level = (Sqreen.features['perf_level'] || 1).to_i
        Sqreen::Weave.logger.debug { "request budget: #{budget.to_h} timed.level: #{timed_level}" } if Sqreen::Weave.logger.debug?

        Thread.current[:sqreen_http_request] = {
          request_timer: request_timer,
          sqreen_timer: sqreen_timer,
          time_budget_expended: false,
          time_budget_threshold: request_budget_threshold,
          time_budget_dynamic: request_budget_is_dynamic,
          time_budget_ratio: request_budget_ratio,
          time_budget: request_budget,
          timed_callbacks: [],
          timed_hooks: [],
          timed_level: timed_level,
          skipped_callbacks: [],
          # timed_shrinkwrap: shrinkwrap_timer,
        }

        # shrinkwrap_timer.stop
      end

      ensured('weave,meta,request', rank: 100000, mandatory: true) do |_call|
        request = Thread.current[:sqreen_http_request]

        next if request.nil?

        # shrinkwrap_timer = request[:timed_shrinkwrap]
        # shrinkwrap_timer.start

        Thread.current[:sqreen_http_request] = nil
        request_timer = request[:request_timer]
        now = request_timer.stop

        if request[:timed_level] >= 1
          request[:timed_callbacks].each do |timer|
            duration = timer.duration

            timer.tag =~ /weave,rule=(.*)$/ && rule = $1
            next unless rule

            whence = case timer.tag
                     when /@before/ then 'pre'
                     when /@after/  then 'post'
                     when /@raised/ then 'failing'
                     end
            next unless whence

            metric_name = "sq.#{rule}.#{whence}"
            metrics_engine.update(metric_name, now, nil, duration * 1000)
            # Sqreen.observations_queue.push([metric_name, nil, duration * 1000, utc_now])
          end

          request[:timed_hooks].each do |timer|
            duration = timer.duration
            metrics_engine.update('sq.hook.overhead', now, nil, duration * 1000)
            # Sqreen.observations_queue.push(['sq.hook.overhead', nil, duration * 1000, utc_now])
          end
        end

        sqreen_timer = request[:sqreen_timer]
        total = sqreen_timer.duration
        Sqreen::Weave.logger.debug { "request sqreen_timer.total: #{'%.03fus' % (total * 1_000_000)}" } if Sqreen::Weave.logger.debug?
        total = request_timer.duration
        Sqreen::Weave.logger.debug { "request request_timer.total: #{'%.03fus' % (total * 1_000_000)}" } if Sqreen::Weave.logger.debug?

        if request[:timed_level] >= 2
          skipped = request[:skipped_callbacks].map(&:name)
          Sqreen::Weave.logger.debug { "request callback.skipped.count: #{skipped.count}" } if Sqreen::Weave.logger.debug?
          timings = request[:timed_callbacks].map(&:to_s)
          total = request[:timed_callbacks].sum(&:duration)
          Sqreen::Weave.logger.debug { "request callback.total: #{'%.03fus' % (total * 1_000_000)} callback.count: #{timings.count}" } if Sqreen::Weave.logger.debug?
          timings = request[:timed_hooks].map(&:to_s)
          total = request[:timed_hooks].sum(&:duration)
          Sqreen::Weave.logger.debug { "request hook.total: #{'%.03fus' % (total * 1_000_000)} hook.count: #{timings.count}" } if Sqreen::Weave.logger.debug?
        end

        skipped = request[:skipped_callbacks].map(&:name)
        skipped_rule_name = skipped.first && skipped.first =~ /weave,rule=(.*)$/ && $1
        metrics_engine.update('request_overtime', now, skipped_rule_name, 1) if skipped_rule_name
        # Sqreen.observations_queue.push(['request_overtime', skipped_rule_name, 1, utc_now]) if skipped_rule_name

        sqreen_request_duration = sqreen_timer.duration
        metrics_engine.update('sq', now, nil, sqreen_request_duration * 1000)
        # Sqreen.observations_queue.push(['sq', nil, sqreen_request_duration * 1000, utc_now])

        request_duration = request_timer.duration
        metrics_engine.update('req', now, nil, request_duration * 1000)
        # Sqreen.observations_queue.push(['req', nil, request_duration * 1000, utc_now])

        sqreen_request_ratio = (sqreen_request_duration * 100.0) / (request_duration - sqreen_request_duration)
        metrics_engine.update('pct', now, nil, sqreen_request_ratio)
        # Sqreen.observations_queue.push(['pct', nil, sqreen_request_ratio, utc_now])
        Sqreen::Weave.logger.debug { "request sqreen_timer.ratio: #{'%.03f' % (sqreen_request_ratio / 100.0)}" } if Sqreen::Weave.logger.debug?

        if request[:timed_level] >= 2
          tallies = Hash.new(0.0)
          request[:timed_callbacks].each do |timer|
            duration = timer.duration

            timer.tag =~ /weave,rule=(.*)$/ && rule = $1
            next unless rule

            whence = case timer.tag
                     when /@before/ then 'pre'
                     when /@after/  then 'post'
                     when /@raised/ then 'failing'
                     end
            next unless whence

            metric_name = "req.sq.#{rule}.#{whence}"
            tallies[metric_name] += duration
          end
          tallies.each do |metric_name, duration|
            metrics_engine.update(metric_name, now, nil, duration * 1000)
            # Sqreen.observations_queue.push([metric_name, nil, duration * 1000, utc_now])
          end

          duration = request[:timed_hooks].sum(&:duration)
          metrics_engine.update('req.sq.hook.overhead', now, nil, duration * 1000)
          # Sqreen.observations_queue.push(['req.sq.hook.overhead', nil, duration * 1000, utc_now])
        end

        # shrinkwrap_timer.stop

        # duration = shrinkwrap_timer.duration
        # metrics_engine.update('sq.shrinkwrap', now, nil, duration * 1000)
      end
    end.install

    ### globally declare instrumentation ready
    Sqreen.instrumentation_ready = true
    Sqreen::Weave.logger.info { "Instrumentation activated" }
  end

  # needed by Sqreen::Runner
  def remove_all_callbacks
    Sqreen.instrumentation_ready = false
    Sqreen::Weave.logger.info { "Instrumentation deactivated" }

    loop do
      hook = @hooks.pop
      break unless hook
      Sqreen::Weave.logger.debug { "hook.deinstrument: #{hook}" }
      hook.uninstall
      hook.clear
    end
  end

  # needed by #instrument!
  def add_callback(rule, callback, strategy)
    Sqreen::Weave.logger.debug { "Adding rule: #{rule} callback: #{callback}" }
    klass = callback.klass
    method = callback.method

    if (call_count = ENV['SQREEN_DEBUG_CALL_COUNT'])
      call_count = JSON.parse(call_count)
      if callback.respond_to?(:rule_name) && call_count.key?(callback.rule_name)
        count = call_count[callback.rule_name]
        Sqreen::Weave.logger.debug { "override rule: #{callback.rule_name} call_count: #{count.inspect}" }
        callback.instance_eval { @call_count_interval = call_count[callback.rule_name] }
      end
    end

    if Sqreen::Graft::HookPoint.new("#{klass}.#{method}").exist?
      hook_point = "#{klass}.#{method}"
    elsif Sqreen::Graft::HookPoint.new("#{klass}##{method}").exist?
      hook_point = "#{klass}##{method}"
    end

    return if hook_point.nil?

    priority = callback.priority || 100
    block = callback.respond_to?(:block) ? callback.block : true
    ignore = -> { callback.whitelisted? } if callback.respond_to?(:whitelisted?)

    hook = Sqreen::Graft::Hook[hook_point, strategy]
    hook.add do
      if callback.pre?
        before(rule, rank: priority, mandatory: !callback.overtimeable, flow: block, ignore: ignore) do |call, b|
          next unless Thread.current[:sqreen_http_request]

          i = call.instance
          a = call.args
          r = call.remaining

          begin
            ret = callback.pre(i, a, r)
          rescue StandardError => e
            Sqreen::Weave.logger.warn { "#{rule} klass=#{callback.klass} method=#{callback.method} when=#pre instance=#{i} => exception=#{e}" }
            if callback.respond_to?(:record_exception)
              callback.record_exception(e)
            else
              Sqreen::RemoteException.record(e)
            end
          end

          next if ret.nil? || !ret.is_a?(Hash)

          throw_val =
            case ret[:status]
            when :skip, 'skip'
              b.return(ret[:new_return_value]).break! if ret.key?(:new_return_value)
            when :modify_args, 'modify_args'
              b.args(ret[:args])
            when :raise, 'raise'
              if ret.key?(:exception)
                b.raise(ret[:exception])
              else
                b.raise(Sqreen::AttackBlocked.new("Sqreen blocked a security threat (type: #{callback.rule_name}). No action is required."))
              end
            end

          next unless throw_val
          throw_val.break! if ret[:skip_rem_cbs]
          throw(b, throw_val)
        end
      end

      if callback.post?
        after(rule, rank: -priority, mandatory: !callback.overtimeable, flow: block, ignore: ignore) do |call, b|
          next unless Thread.current[:sqreen_http_request]

          i = call.instance
          v = call.returned
          a = call.args
          r = call.remaining

          begin
            ret = callback.post(v, i, a, r)
          rescue StandardError => e
            Sqreen::Weave.logger.warn { "#{rule} klass=#{callback.klass} method=#{callback.method} when=#post instance=#{i} => exception=#{e}" }
            if callback.respond_to?(:record_exception)
              callback.record_exception(e)
            else
              Sqreen::RemoteException.record(e)
            end
          end

          case ret[:status]
          when :override, 'override'
            throw(b, b.return(ret[:new_return_value])) if ret.key?(:new_return_value)
          when :raise, 'raise'
            throw(b, b.raise(ret[:exception])) if ret.key?(:exception)
            throw(b, b.raise(Sqreen::AttackBlocked.new("Sqreen blocked a security threat (type: #{callback.rule_name}). No action is required.")))
          end unless ret.nil? || !ret.is_a?(Hash)
        end
      end

      if callback.failing?
        raised(rule, rank: priority, mandatory: !callback.overtimeable, flow: block, ignore: ignore) do |call, b|
          next unless Thread.current[:sqreen_http_request]

          i = call.instance
          e = call.raised
          a = call.args
          r = call.remaining

          begin
            ret = callback.failing(e, i, a, r)
          rescue StandardError => e
            Sqreen::Weave.logger.warn { "#{rule} klass=#{callback.klass} method=#{callback.method} when=#failing instance=#{i} => exception=#{e}" }
            if callback.respond_to?(:record_exception)
              callback.record_exception(e)
            else
              Sqreen::RemoteException.record(e)
            end
          end

          throw(b, b.raise(e)) if ret.nil? || !ret.is_a?(Hash)

          case ret[:status]
          when :override, 'override'
            throw(b, b.return(ret[:new_return_value])) if ret.key?(:new_return_value)
          when :retry, 'retry'
            throw(b, b.retry)
          when :raise, 'raise'
            throw(b, b.raise(ret[:exception])) if ret.key?(:exception)
            throw(b, b.raise(Sqreen::AttackBlocked.new("Sqreen blocked a security threat (type: #{callback.rule_name}). No action is required.")))
          when :reraise, 'reraise'
            throw(b, b.raise(e))
          else
            throw(b, b.raise(e))
          end unless ret.nil? || !ret.is_a?(Hash)
        end
      end
    end.install

    hook
  end

  # needed by Sqreen::Rules.cb_from_rule
  def valid_method?(klass, method)
    if Sqreen::Graft::HookPoint.new("#{klass}.#{method}").exist?
      Sqreen::Weave.logger.debug { "HookPoint found: #{klass}.#{method}" }
      true
    elsif Sqreen::Graft::HookPoint.new("#{klass}##{method}").exist?
      Sqreen::Weave.logger.debug { "HookPoint found: #{klass}##{method}" }
      true
    else
      Sqreen::Weave.logger.debug { "HookPoint not found: #{klass} #{method}" }
      false
    end
  end

  # needed by #instrument!
  def hardcoded_callbacks(framework)
    [
      ### callback for performing sec responses based on ip
      ### init redefined to implement smartass way to hook it upon the
      ### framework's middleware #call
      Sqreen::Rules::RunReqStartActions.new(framework),
      ### callback for performing sec responses based on user
      Sqreen::Rules::RunUserActions.new(Sqreen, :identify, 0),
      ### callback for performing sec responses based on user
      Sqreen::Rules::RunUserActions.new(Sqreen, :auth_track, 1),
    ]
  end
end