require 'agents'
require 'agents/instrumentation'
require 'json'

# rubocop:disable Metrics/ClassLength
class Captain::Assistant::AgentRunnerService
  include Integrations::LlmInstrumentationConstants

  FAQ_UNCERTAINTY_PATTERNS = [
    /\bnao (sei|tenho|consigo|possuo)\b/i,
    /\bi do not (know|have access)\b/i,
    /\bi don't (know|have|have access)\b/i,
    /\bcan'?t (access|help|provide)\b/i
  ].freeze
  # Patterns must imply an actual price answer, not casual mentions of
  # stay types. E.g. "Vou te transferir pra Daniela pra confirmar a
  # Stilo pra pernoite" legitimately mentions "pernoite" but is a
  # handoff, NOT a price response — keep the guardrail from hijacking it.
  FAQ_PRICE_PATTERNS = [
    /r\$\s*\d+/i,
    /\b\d+[,.]?\d*\s*(reais|real)\b/i,
    /\b(preco|preço|valor|preços|valores|cust[ao])\b/i
  ].freeze
  FAQ_NOT_FOUND_FALLBACK = 'Consultei o FAQ e não encontrei essa informação cadastrada ainda. Posso te ajudar com outro tema ou te transferir para um atendente.'.freeze

  CONVERSATION_STATE_ATTRIBUTES = %i[
    id display_id inbox_id contact_id status priority
    label_list custom_attributes additional_attributes
  ].freeze

  CONTACT_STATE_ATTRIBUTES = %i[
    id name email phone_number identifier contact_type
    custom_attributes additional_attributes
  ].freeze

  def initialize(assistant:, conversation: nil, callbacks: {})
    @assistant = assistant
    @conversation = conversation
    @callbacks = callbacks
  end

  # Hard ceilings to prevent runaway token burn. See memory file
  # feedback_never_touch_captain_without_safety_caps.md — two real-world incidents.
  MAX_TURNS_PER_MESSAGE = 15           # Cap inside a single run() call
  MAX_TURNS_PER_CONVERSATION = 30      # Cap across the whole conversation lifetime
  TOOL_LOOP_THRESHOLD = 3              # Same (tool_name, args) invoked N+ times = loop
  RUNNER_TIMEOUT_SECS = 45             # Kill runner.run if LLM/HTTP hangs past this

  # rubocop:disable Metrics/MethodLength, Metrics/AbcSize
  def generate_response(message_history: [])
    if conversation_turn_limit_exceeded?
      return bot_handoff_response('Conversa atingiu o limite de interações automáticas. Transferindo para atendimento humano.')
    end

    agents = build_and_wire_agents
    context = build_context(message_history)
    message_to_process = extract_last_user_message(message_history)
    runner = Agents::Runner.with_agents(*agents)
    runner = add_usage_metadata_callback(runner)
    runner = add_callbacks_to_runner(runner) if @callbacks.any?
    install_instrumentation(runner)
    # max_turns is the hard safety cap: each "turn" = one LLM call + optional tool calls.
    # MAX_TURNS_PER_MESSAGE is plenty for normal flows while keeping a burn-budget ceiling.
    # Timeout guards against HTTP hangs on the LLM side (OpenAI slow / network flake):
    # without it, the job hangs indefinitely and no post-hoc loop detection ever fires.
    result = Timeout.timeout(RUNNER_TIMEOUT_SECS) do
      runner.run(message_to_process, context: context, max_turns: MAX_TURNS_PER_MESSAGE)
    end

    if tool_loop_detected?(result)
      Rails.logger.error("[Captain V2] Tool loop detected on conv #{@conversation&.id}. Triggering bot_handoff.")
      trigger_bot_handoff!
      return bot_handoff_response('Detectei um comportamento repetitivo. Transferindo para atendimento humano.')
    end

    increment_conversation_turn_count!
    process_agent_result(result, original_query: message_to_process)
  rescue Timeout::Error
    Rails.logger.error("[Captain V2] runner.run timed out after #{RUNNER_TIMEOUT_SECS}s on conv #{@conversation&.id}. Triggering bot_handoff.")
    trigger_bot_handoff!
    bot_handoff_response('A IA demorou mais do que o esperado. Transferindo para atendimento humano.')
  rescue StandardError => e
    # when running the agent runner service in a rake task, the conversation might not have an account associated
    # for regular production usage, it will run just fine
    ChatwootExceptionTracker.new(e, account: @conversation&.account).capture_exception
    Rails.logger.error "[Captain V2] AgentRunnerService error: #{e.message}"
    Rails.logger.error e.backtrace.join("\n")

    error_response(e.message)
  end
  # rubocop:enable Metrics/MethodLength, Metrics/AbcSize

  private

  # --- Rate limiting / runaway protection ---

  # True when this conversation already burned the per-conversation turn budget.
  # Anything beyond MAX_TURNS_PER_CONVERSATION is flagged as runaway and we hand
  # off to a human. The counter lives on conversation.custom_attributes so it
  # survives Sidekiq restarts and is queryable from dashboards.
  def conversation_turn_limit_exceeded?
    return false if @conversation.blank?

    count = @conversation.custom_attributes.to_h['captain_turn_count'].to_i
    count >= MAX_TURNS_PER_CONVERSATION
  end

  def increment_conversation_turn_count!
    return if @conversation.blank?

    attrs = @conversation.custom_attributes.to_h
    attrs['captain_turn_count'] = attrs['captain_turn_count'].to_i + 1
    # rubocop:disable Rails/SkipsModelValidations
    @conversation.update_columns(custom_attributes: attrs)
    # rubocop:enable Rails/SkipsModelValidations
  rescue StandardError => e
    Rails.logger.warn("[Captain V2] increment_conversation_turn_count! failed: #{e.message}")
  end

  # Inspects the messages emitted during the run and flags repeated tool
  # invocations with identical arguments as a runaway loop. Real incident
  # that motivated this: Daniela called faq_lookup('preço pernoite alexa')
  # dozens of times in the same run, burning tokens silently.
  def tool_loop_detected?(result)
    tool_signatures = Array(result&.messages).flat_map do |msg|
      tool_calls = msg[:tool_calls] || msg['tool_calls'] || []
      Array(tool_calls).map do |tc|
        name = (tc[:name] || tc['name']).to_s
        args = tc[:arguments] || tc['arguments']
        args_str = args.is_a?(Hash) ? args.to_json : args.to_s
        "#{name}|#{args_str}"
      end
    end.reject(&:empty?)

    return false if tool_signatures.empty?

    tool_signatures.tally.any? { |_, count| count >= TOOL_LOOP_THRESHOLD }
  end

  def trigger_bot_handoff!
    return if @conversation.blank?

    @conversation.bot_handoff! if @conversation.respond_to?(:bot_handoff!)
  rescue StandardError => e
    Rails.logger.warn("[Captain V2] trigger_bot_handoff! failed: #{e.message}")
  end

  def bot_handoff_response(message)
    { 'response' => message, 'reasoning' => 'Runaway protection triggered', 'reaction_emoji' => '' }
  end

  # --- End rate limiting / runaway protection ---

  def build_context(message_history)
    last_active_scenario_agent = extract_last_scenario_agent(message_history)

    conversation_history = message_history.map do |msg|
      content = extract_text_from_content(msg[:content])

      {
        role: msg[:role].to_sym,
        content: content,
        # AgentRunner selects the starting agent from the last assistant message
        # with `agent_name` in conversation_history. We always want each turn to
        # start from the orchestrator and let it decide whether to handoff again.
        agent_name: nil
      }
    end

    {
      session_id: "#{@assistant.account_id}_#{@conversation&.display_id}",
      # Default: start each turn from the orchestrator (Jasmine).
      # Exception: if there is an active workflow (e.g. pending reservation),
      # continue with the last active scenario agent so multi-turn flows
      # like reservations don't get interrupted by the orchestrator stealing the turn.
      current_agent: pick_starting_agent(last_active_scenario_agent),
      conversation_history: conversation_history,
      state: build_state
    }
  end

  # Reads the last assistant message that came from a scenario (not the orchestrator).
  # Returns nil if no scenario was recently active.
  def extract_last_scenario_agent(message_history)
    return nil if message_history.blank?

    orchestrator = assistant_agent_name
    last_assistant = message_history.reverse.find do |msg|
      next false unless msg[:role] == 'assistant'

      name = msg[:agent_name].to_s
      name.present? && name != orchestrator
    end
    last_assistant&.dig(:agent_name)
  end

  # Picks which agent should start the next turn:
  # - If there is an active workflow on this conversation (e.g. reservation pending),
  #   continue with the last scenario agent that was active.
  # - Otherwise, default to the orchestrator (Jasmine).
  def pick_starting_agent(last_scenario_agent)
    default = assistant_agent_name
    return default if @conversation.blank?
    return default if last_scenario_agent.blank?

    return last_scenario_agent if active_workflow?

    default
  end

  # Detects if the conversation is mid-workflow (e.g. ongoing reservation).
  # Safe to extend: any condition here keeps the user inside the active scenario.
  def active_workflow?
    return false if @conversation.blank?

    if defined?(Captain::Reservation)
      pending_reservation = Captain::Reservation
                            .where(conversation_id: @conversation.id)
                            .where.not(status: %w[cancelled completed])
                            .exists?
      return true if pending_reservation
    end

    label_list = @conversation.respond_to?(:label_list) ? @conversation.label_list : nil
    Array(label_list).any? { |label| label.to_s.match?(/aguardando|pending|em_andamento/i) }
  rescue StandardError => e
    Rails.logger.warn("[Captain V2] active_workflow? check failed: #{e.message}")
    false
  end

  def assistant_agent_name
    @assistant.name.to_s.parameterize(separator: '_')
  end

  def extract_last_user_message(message_history)
    last_user_msg = message_history.reverse.find { |msg| msg[:role] == 'user' }

    extract_text_from_content(last_user_msg[:content], as_string: true)
  end

  def extract_text_from_content(content, as_string: false)
    raw_content = content.is_a?(RubyLLM::Content::Raw) ? content.value : content

    # Handle structured output from agents
    return raw_content[:response] || raw_content['response'] || raw_content.to_s if raw_content.is_a?(Hash)

    return raw_content unless raw_content.is_a?(Array)

    if as_string
      text_parts = raw_content.select { |part| part[:type] == 'text' }.pluck(:text)
      text_parts.join(' ')
    else
      content
    end
  end

  # Response formatting methods
  def process_agent_result(result, original_query:)
    Rails.logger.info "[Captain V2] Agent result: #{result.inspect}"
    response = format_response(result.output)

    # Extract agent name from context
    response['agent_name'] = result.context&.dig(:current_agent)
    enforce_faq_guardrail(response, result, original_query: original_query)
  end

  def enforce_faq_guardrail(response, result, original_query:)
    return response unless faq_feature_enabled?
    return response if response['response'] == 'conversation_handoff'
    # Scenario agents have authoritative data in their own instructions — skip guardrail
    return response if response['agent_name'].present? && response['agent_name'] != assistant_agent_name

    guardrail_reason = faq_guardrail_reason(response['response'])
    return response if guardrail_reason.blank?
    return response if faq_lookup_called?(result, original_query: original_query)
    return response if original_query.blank?

    fallback_answer = faq_fallback_answer(original_query, response_text: response['response'])
    Rails.logger.warn("[Captain V2] FAQ guardrail triggered (#{guardrail_reason}) for query: #{original_query.inspect}")

    if fallback_answer.present?
      response['response'] = fallback_answer
      response['reasoning'] = "FAQ guardrail applied due to #{guardrail_reason} response without faq_lookup call."
    else
      response['response'] = FAQ_NOT_FOUND_FALLBACK
      response['reasoning'] = 'FAQ guardrail applied; no FAQ entry found for query.'
    end

    response
  end

  def faq_feature_enabled?
    ActiveModel::Type::Boolean.new.cast(@assistant.feature_faq)
  end

  def uncertainty_response?(text)
    normalized = I18n.transliterate(text.to_s).downcase
    FAQ_UNCERTAINTY_PATTERNS.any? { |pattern| normalized.match?(pattern) }
  end

  def price_response?(text)
    normalized = I18n.transliterate(text.to_s).downcase
    FAQ_PRICE_PATTERNS.any? { |pattern| normalized.match?(pattern) }
  end

  def faq_guardrail_reason(text)
    return 'uncertain' if uncertainty_response?(text)
    return 'price' if price_response?(text)

    nil
  end

  def faq_lookup_called?(result, original_query:)
    messages_for_current_turn(result, original_query).any? do |message|
      tool_calls = message[:tool_calls] || message['tool_calls'] || []
      Array(tool_calls).any? do |tool_call|
        tool_name = (tool_call[:name] || tool_call['name']).to_s
        tool_name.end_with?('faq_lookup')
      end
    end
  end

  def messages_for_current_turn(result, original_query)
    messages = Array(result.messages)
    return messages if messages.empty? || original_query.blank?

    normalized_query = original_query.to_s.strip
    last_user_index = messages.rindex do |message|
      role = (message[:role] || message['role']).to_s
      next false unless role == 'user'

      message_content = extract_text_from_content(message[:content] || message['content']).to_s.strip
      message_content == normalized_query
    end

    return messages unless last_user_index

    messages[(last_user_index + 1)..] || []
  end

  def faq_fallback_answer(query, response_text: nil)
    faq_query_candidates(query, response_text: response_text).each do |candidate|
      responses = @assistant.responses.approved.search(candidate).to_a
      Rails.logger.info "[Captain V2] FAQ guardrail fallback results=#{responses.size} query=#{candidate.inspect}"
      return responses.first&.answer if responses.present?
    end

    nil
  rescue StandardError => e
    Rails.logger.warn("[Captain V2] FAQ guardrail fallback failed: #{e.message}")
    nil
  end

  def faq_query_candidates(original_query, response_text: nil)
    candidates = [original_query.to_s]
    response_body = response_text.to_s
    candidates << response_body if response_body.present?

    suite_hint = response_body.match(/su[ií]te\s+([a-z0-9]+)/i)&.captures&.first
    candidates << "valor da suíte #{suite_hint}" if suite_hint.present?

    candidates.map(&:squish).reject(&:blank?).uniq
  end

  def format_response(output)
    return output.with_indifferent_access if output.is_a?(Hash)

    parsed_output = parse_structured_output_string(output.to_s)
    return parsed_output if parsed_output.present?

    # Fallback for backwards compatibility
    {
      'response' => output.to_s,
      'reasoning' => 'Processed by agent'
    }
  end

  def error_response(error_message)
    {
      'response' => 'conversation_handoff',
      'reasoning' => "Error occurred: #{error_message}"
    }
  end

  def parse_structured_output_string(output_text)
    return nil if output_text.blank?

    parsed_candidates = extract_json_objects(output_text).filter_map do |json_object|
      JSON.parse(json_object)
    rescue JSON::ParserError
      nil
    end

    candidate = parsed_candidates.reverse.find do |item|
      item.is_a?(Hash) && item['response'].present?
    end
    return nil unless candidate

    {
      'response' => candidate['response'].to_s,
      'reasoning' => candidate['reasoning'].presence || 'Processed by agent',
      'reaction_emoji' => candidate['reaction_emoji'].to_s
    }
  end

  # rubocop:disable Metrics/MethodLength
  def extract_json_objects(text)
    objects = []
    start_index = nil
    depth = 0
    in_string = false
    escaped = false

    text.each_char.with_index do |char, index|
      if in_string
        if escaped
          escaped = false
        elsif char == '\\'
          escaped = true
        elsif char == '"'
          in_string = false
        end
        next
      end

      if char == '"'
        in_string = true
      elsif char == '{'
        start_index = index if depth.zero?
        depth += 1
      elsif char == '}'
        next if depth.zero?

        depth -= 1
        if depth.zero? && start_index
          objects << text[start_index..index]
          start_index = nil
        end
      end
    end

    objects
  end
  # rubocop:enable Metrics/MethodLength

  def build_state
    state = {
      account_id: @assistant.account_id,
      assistant_id: @assistant.id,
      assistant_config: @assistant.config
    }

    if @conversation
      state[:conversation] = @conversation.attributes.symbolize_keys.slice(*CONVERSATION_STATE_ATTRIBUTES)
      state[:contact] = @conversation.contact.attributes.symbolize_keys.slice(*CONTACT_STATE_ATTRIBUTES) if @conversation.contact
    end

    state
  end

  def build_and_wire_agents
    assistant_agent = build_orchestrator_agent_with_memory
    scenario_agents = @assistant.scenarios.enabled.map(&:agent)

    # Unidirectional handoff: orchestrator -> scenarios only.
    #
    # Historically we also registered scenarios -> orchestrator as a safety
    # valve so a confused scenario could escape to Jasmine. In practice this
    # caused ping-pong INSIDE a single run: orchestrator hands off to Daniela,
    # Daniela immediately hands back, Jasmine responds with "Vou te transferir
    # para a Daniela" AFTER the user was already with Daniela.
    #
    # The runaway-loop fear that originally justified the back-edge (Daniela
    # spamming faq_lookup when confused) is now contained by TOOL_LOOP_THRESHOLD
    # / MAX_TURNS_PER_MESSAGE in generate_response — any repeated tool call or
    # turn exhaustion triggers bot_handoff to a human. So the back-edge is no
    # longer a required safety net, and removing it fixes the ping-pong.
    assistant_agent.register_handoffs(*scenario_agents) if scenario_agents.any?

    [assistant_agent] + scenario_agents
  end

  # Builds the orchestrator agent and wraps its instructions lambda with
  # optional Captain ContactMemory recall. Uses Agents::Agent#clone (public
  # API) so the original agent stays immutable and thread-safe.
  def build_orchestrator_agent_with_memory
    default_agent = @assistant.agent
    return default_agent unless memory_injector.recall_enabled?

    original_instructions = default_agent.instructions
    default_agent.clone(instructions: build_wrapped_instructions(original_instructions))
  end

  # Returns a lambda that delegates to build_system_prompt_with_memory, so
  # the runtime path and the test-facing helper share ONE implementation.
  def build_wrapped_instructions(original_instructions)
    lambda do |context|
      base_prompt = original_instructions.respond_to?(:call) ? original_instructions.call(context) : original_instructions.to_s
      query_text = last_user_message_from_context(context)
      build_system_prompt_with_memory(query_text, base_prompt)
    end
  end

  def last_user_message_from_context(context)
    history = context&.context&.dig(:conversation_history) || []
    last_user = history.reverse.find { |msg| msg[:role].to_sym == :user }
    return '' if last_user.blank?

    extract_text_from_content(last_user[:content], as_string: true).to_s
  end

  # Canonical method: takes the query + pre-built base prompt and returns
  # the final prompt with an optional <memoria_cliente> block appended.
  # Both the runtime lambda and specs call through this method.
  def build_system_prompt_with_memory(query_text, base_prompt)
    memory_injector.append_memory_block(base_prompt, query_text)
  end

  # Memoized per service instance. Safe because AgentRunnerService is
  # constructed fresh per conversation turn.
  def memory_injector
    @memory_injector ||= Captain::Assistant::MemoryPromptInjector.new(conversation: @conversation)
  end

  def install_instrumentation(runner)
    return unless ChatwootApp.otel_enabled?

    Agents::Instrumentation.install(
      runner,
      tracer: OpentelemetryConfig.tracer,
      trace_name: 'llm.captain_v2',
      span_attributes: {
        ATTR_LANGFUSE_TAGS => ['captain_v2'].to_json
      },
      attribute_provider: ->(context_wrapper) { dynamic_trace_attributes(context_wrapper) }
    )
  end

  def dynamic_trace_attributes(context_wrapper)
    state = context_wrapper&.context&.dig(:state) || {}
    conversation = state[:conversation] || {}
    {
      ATTR_LANGFUSE_USER_ID => state[:account_id],
      format(ATTR_LANGFUSE_METADATA, 'assistant_id') => state[:assistant_id],
      format(ATTR_LANGFUSE_METADATA, 'conversation_id') => conversation[:id],
      format(ATTR_LANGFUSE_METADATA, 'conversation_display_id') => conversation[:display_id]
    }.compact.transform_values(&:to_s)
  end

  def add_callbacks_to_runner(runner)
    runner = add_agent_thinking_callback(runner) if @callbacks[:on_agent_thinking]
    runner = add_tool_start_callback(runner) if @callbacks[:on_tool_start]
    runner = add_tool_complete_callback(runner) if @callbacks[:on_tool_complete]
    runner = add_agent_handoff_callback(runner) if @callbacks[:on_agent_handoff]
    runner
  end

  def add_usage_metadata_callback(runner)
    return runner unless ChatwootApp.otel_enabled?

    handoff_tool_name = Captain::Tools::HandoffTool.new(@assistant).name

    runner.on_tool_complete do |tool_name, _tool_result, context_wrapper|
      track_handoff_usage(tool_name, handoff_tool_name, context_wrapper)
    end

    runner.on_run_complete do |_agent_name, _result, context_wrapper|
      write_credits_used_metadata(context_wrapper)
    end
    runner
  end

  def track_handoff_usage(tool_name, handoff_tool_name, context_wrapper)
    return unless context_wrapper&.context
    return unless tool_name.to_s == handoff_tool_name

    context_wrapper.context[:captain_v2_handoff_tool_called] = true
  end

  def write_credits_used_metadata(context_wrapper)
    root_span = context_wrapper&.context&.dig(:__otel_tracing, :root_span)
    return unless root_span

    credit_used = !context_wrapper.context[:captain_v2_handoff_tool_called]
    root_span.set_attribute(format(ATTR_LANGFUSE_METADATA, 'credit_used'), credit_used.to_s)
  end

  def add_agent_thinking_callback(runner)
    runner.on_agent_thinking do |*args|
      @callbacks[:on_agent_thinking].call(*args)
    rescue StandardError => e
      Rails.logger.warn "[Captain] Callback error for agent_thinking: #{e.message}"
    end
  end

  def add_tool_start_callback(runner)
    runner.on_tool_start do |*args|
      @callbacks[:on_tool_start].call(*args)
    rescue StandardError => e
      Rails.logger.warn "[Captain] Callback error for tool_start: #{e.message}"
    end
  end

  def add_tool_complete_callback(runner)
    runner.on_tool_complete do |*args|
      @callbacks[:on_tool_complete].call(*args)
    rescue StandardError => e
      Rails.logger.warn "[Captain] Callback error for tool_complete: #{e.message}"
    end
  end

  def add_agent_handoff_callback(runner)
    runner.on_agent_handoff do |*args|
      @callbacks[:on_agent_handoff].call(*args)
    rescue StandardError => e
      Rails.logger.warn "[Captain] Callback error for agent_handoff: #{e.message}"
    end
  end
end
# rubocop:enable Metrics/ClassLength