defmodule ToweropsWeb.Api.V1.EscalationPoliciesController do
  @moduledoc """
  API controller for managing escalation policies.

  All endpoints require API token authentication and operations are scoped
  to the organization associated with the token.
  """
  use ToweropsWeb, :controller

  alias Towerops.OnCall
  alias Towerops.OnCall.EscalationPolicy
  alias Towerops.OnCall.EscalationRule
  alias Towerops.OnCall.EscalationTarget
  alias Towerops.Repo
  alias ToweropsWeb.Api.ParamFilter
  alias ToweropsWeb.Api.V1.ResourceController, as: Resources
  alias ToweropsWeb.ScopedResource

  require Logger

  # --- Policy CRUD ---

  @doc "GET /api/v1/escalation_policies"
  def index(conn, _params) do
    organization_id = conn.assigns.current_organization_id

    policies =
      organization_id
      |> OnCall.list_escalation_policies()
      |> Enum.map(&format_policy/1)

    json(conn, %{escalation_policies: policies})
  end

  @doc "POST /api/v1/escalation_policies"
  def create(conn, %{"escalation_policy" => policy_params}) do
    organization_id = conn.assigns.current_organization_id

    attrs =
      policy_params
      |> ParamFilter.strip_sensitive()
      |> Map.put("organization_id", organization_id)

    Resources.created_or_error(conn, OnCall.create_escalation_policy(attrs), &format_policy/1)
  end

  def create(conn, _params) do
    Resources.missing_param(conn, "escalation_policy")
  end

  @doc "GET /api/v1/escalation_policies/:id"
  def show(conn, %{"id" => id}) do
    organization_id = conn.assigns.current_organization_id

    Resources.fetch_and_render(
      conn,
      EscalationPolicy,
      id,
      organization_id,
      [rules: :targets],
      &format_policy_detail/1,
      "Escalation policy not found"
    )
  end

  @doc "PATCH /api/v1/escalation_policies/:id"
  def update(conn, %{"id" => id, "escalation_policy" => policy_params}) do
    organization_id = conn.assigns.current_organization_id

    Resources.update_and_render(
      conn,
      EscalationPolicy,
      id,
      organization_id,
      %{
        context: OnCall,
        update_fn: :update_escalation_policy,
        params: ParamFilter.strip_sensitive(policy_params),
        format_fn: &format_policy/1,
        not_found_msg: "Escalation policy not found"
      }
    )
  end

  def update(conn, _params) do
    Resources.missing_param(conn, "escalation_policy")
  end

  @doc "DELETE /api/v1/escalation_policies/:id"
  def delete(conn, %{"id" => id}) do
    organization_id = conn.assigns.current_organization_id

    Resources.delete_and_render(
      conn,
      EscalationPolicy,
      id,
      organization_id,
      OnCall,
      :delete_escalation_policy,
      "Escalation policy not found"
    )
  end

  # --- Rules ---

  @doc "POST /api/v1/escalation_policies/:id/rules"
  def create_rule(conn, %{"id" => policy_id, "rule" => rule_params}) do
    organization_id = conn.assigns.current_organization_id

    case ScopedResource.fetch(EscalationPolicy, policy_id, organization_id) do
      {:ok, _policy} ->
        attrs = Map.put(rule_params, "escalation_policy_id", policy_id)

        case OnCall.create_escalation_rule(attrs) do
          {:ok, rule} ->
            conn
            |> put_status(:created)
            |> json(format_rule(rule))

          {:error, %Ecto.Changeset{} = changeset} ->
            Resources.unprocessable_entity(conn, changeset)
        end

      {:error, :not_found} ->
        Resources.not_found(conn, "Escalation policy not found")
    end
  end

  @doc "PATCH /api/v1/escalation_policies/:id/rules/:rule_id"
  def update_rule(conn, %{"id" => policy_id, "rule_id" => rule_id, "rule" => rule_params}) do
    organization_id = conn.assigns.current_organization_id

    with {:ok, _policy} <- ScopedResource.fetch(EscalationPolicy, policy_id, organization_id),
         {:ok, rule} <- fetch_rule(rule_id, policy_id) do
      case OnCall.update_escalation_rule(rule, rule_params) do
        {:ok, updated} ->
          json(conn, format_rule(updated))

        {:error, %Ecto.Changeset{} = changeset} ->
          Resources.unprocessable_entity(conn, changeset)
      end
    else
      {:error, :not_found} ->
        Resources.not_found(conn, "Escalation policy not found")

      {:error, :rule_not_found} ->
        Resources.not_found(conn, "Rule not found")
    end
  end

  @doc "DELETE /api/v1/escalation_policies/:id/rules/:rule_id"
  def delete_rule(conn, %{"id" => policy_id, "rule_id" => rule_id}) do
    organization_id = conn.assigns.current_organization_id

    with {:ok, _policy} <- ScopedResource.fetch(EscalationPolicy, policy_id, organization_id),
         {:ok, rule} <- fetch_rule(rule_id, policy_id) do
      {:ok, _} = OnCall.delete_escalation_rule(rule)
      json(conn, %{success: true})
    else
      {:error, :not_found} ->
        Resources.not_found(conn, "Escalation policy not found")

      {:error, :rule_not_found} ->
        Resources.not_found(conn, "Rule not found")
    end
  end

  # --- Targets ---

  @doc "POST /api/v1/escalation_policies/:id/rules/:rule_id/targets"
  def create_target(conn, %{"id" => policy_id, "rule_id" => rule_id, "target" => target_params}) do
    organization_id = conn.assigns.current_organization_id

    with {:ok, _policy} <- ScopedResource.fetch(EscalationPolicy, policy_id, organization_id),
         {:ok, _rule} <- fetch_rule(rule_id, policy_id) do
      attrs = Map.put(target_params, "escalation_rule_id", rule_id)

      case OnCall.create_escalation_target(attrs) do
        {:ok, target} ->
          conn
          |> put_status(:created)
          |> json(format_target(target))

        {:error, %Ecto.Changeset{} = changeset} ->
          Resources.unprocessable_entity(conn, changeset)
      end
    else
      {:error, :not_found} ->
        Resources.not_found(conn, "Escalation policy not found")

      {:error, :rule_not_found} ->
        Resources.not_found(conn, "Rule not found")
    end
  end

  @doc "DELETE /api/v1/escalation_policies/:id/rules/:rule_id/targets/:target_id"
  def delete_target(conn, %{"id" => policy_id, "rule_id" => rule_id, "target_id" => target_id}) do
    organization_id = conn.assigns.current_organization_id

    with {:ok, _policy} <- ScopedResource.fetch(EscalationPolicy, policy_id, organization_id),
         {:ok, _rule} <- fetch_rule(rule_id, policy_id),
         {:ok, target} <- fetch_target(target_id, rule_id) do
      case OnCall.delete_escalation_target(target) do
        {:ok, _} ->
          json(conn, %{success: true})

        {:error, reason} ->
          Logger.error("Failed to delete escalation target #{target_id}: #{inspect(reason)}")
          conn |> put_status(:internal_server_error) |> json(%{error: "Failed to delete escalation target"})
      end
    else
      {:error, :not_found} ->
        Resources.not_found(conn, "Escalation policy not found")

      {:error, :rule_not_found} ->
        Resources.not_found(conn, "Rule not found")

      {:error, :target_not_found} ->
        Resources.not_found(conn, "Target not found")
    end
  end

  # --- Private helpers ---

  defp fetch_rule(rule_id, policy_id) do
    case Repo.get(EscalationRule, rule_id) do
      %EscalationRule{escalation_policy_id: ^policy_id} = rule -> {:ok, rule}
      _ -> {:error, :rule_not_found}
    end
  end

  defp fetch_target(target_id, rule_id) do
    case Repo.get(EscalationTarget, target_id) do
      %EscalationTarget{escalation_rule_id: ^rule_id} = target -> {:ok, target}
      _ -> {:error, :target_not_found}
    end
  end

  defp format_policy(policy) do
    %{
      id: policy.id,
      name: policy.name,
      description: policy.description,
      repeat_count: policy.repeat_count,
      inserted_at: policy.inserted_at
    }
  end

  defp format_policy_detail(policy) do
    %{
      id: policy.id,
      name: policy.name,
      description: policy.description,
      repeat_count: policy.repeat_count,
      inserted_at: policy.inserted_at,
      rules: Enum.map(policy.rules, &format_rule_detail/1)
    }
  end

  defp format_rule(rule) do
    %{
      id: rule.id,
      position: rule.position,
      timeout_minutes: rule.timeout_minutes,
      escalation_policy_id: rule.escalation_policy_id,
      inserted_at: rule.inserted_at
    }
  end

  defp format_rule_detail(rule) do
    rule
    |> format_rule()
    |> Map.put(:targets, Enum.map(rule.targets, &format_target/1))
  end

  defp format_target(target) do
    %{
      id: target.id,
      target_type: target.target_type,
      user_id: target.user_id,
      schedule_id: target.schedule_id,
      escalation_rule_id: target.escalation_rule_id,
      inserted_at: target.inserted_at
    }
  end
end