towerops/lib/towerops/admin.ex

defmodule Towerops.Admin do
  @moduledoc """
  The Admin context for superuser operations.

  Provides functions for managing users, organizations, and audit logging.
  """
  import Ecto.Query

  alias Towerops.Accounts.User
  alias Towerops.Admin.AuditLog
  alias Towerops.Organizations.Organization
  alias Towerops.Repo

  require Logger

  ## User Management

  @doc """
  Lists all users in the system with their organizations and device counts.

  ## Options

    * `:limit` - Maximum number of users to return (default: 100)
    * `:offset` - Number of users to skip (default: 0)

  ## Examples

      iex> list_all_users()
      [%User{}, ...]

      iex> list_all_users(limit: 50, offset: 100)
      [%User{}, ...]
  """
  @spec list_all_users(Keyword.t()) :: [User.t()]
  def list_all_users(opts \\ []) do
    limit = Keyword.get(opts, :limit, 100)
    offset = Keyword.get(opts, :offset, 0)

    # Subquery to count devices across all user's organizations
    device_count_query =
      from d in "devices",
        join: m in "organization_memberships",
        on: d.organization_id == m.organization_id,
        where: m.user_id == parent_as(:user).id,
        select: count(d.id)

    User
    |> from(as: :user)
    |> select_merge([u], %{device_count: subquery(device_count_query)})
    |> order_by([u], desc: u.inserted_at)
    |> limit(^limit)
    |> offset(^offset)
    |> preload(:organizations)
    |> Repo.all()
  end

  @doc """
  Returns the total count of users in the system.

  ## Examples

      iex> count_users()
      42
  """
  @spec count_users() :: integer()
  def count_users do
    Repo.aggregate(User, :count)
  end

  @doc """
  Deletes a user and creates an audit log entry.

  ## Examples

      iex> delete_user(user_id, superuser_id, "127.0.0.1")
      {:ok, %User{}}

      iex> delete_user(invalid_id, superuser_id, "127.0.0.1")
      ** (Ecto.NoResultsError)
  """
  @spec delete_user(String.t(), String.t(), String.t()) :: {:ok, User.t()} | {:error, any()}
  def delete_user(user_id, superuser_id, ip_address) do
    with {:ok, user} <- fetch_user(user_id) do
      do_delete_user(user, superuser_id, ip_address)
    end
  end

  defp fetch_user(user_id) do
    case Repo.get(User, user_id) do
      nil -> {:error, :not_found}
      user -> {:ok, user}
    end
  end

  defp do_delete_user(user, superuser_id, ip_address) do
    Repo.transaction(fn ->
      create_audit_log(%{
        action: "user_delete",
        superuser_id: superuser_id,
        target_user_id: user.id,
        metadata: %{email: user.email},
        ip_address: ip_address
      })

      Towerops.Accounts.anonymize_user_login_history(user.id)
      Towerops.Accounts.anonymize_user_browser_sessions(user.id)

      case Repo.delete(user) do
        {:ok, deleted_user} ->
          deleted_user

        {:error, changeset} ->
          Logger.error("Failed to delete user: #{inspect(changeset)}")
          Repo.rollback(changeset)
      end
    end)
  end

  ## Organization Management

  @doc """
  Lists all organizations in the system with their memberships.

  ## Options

    * `:limit` - Maximum number of organizations to return (default: 100)
    * `:offset` - Number of organizations to skip (default: 0)

  ## Examples

      iex> list_all_organizations()
      [%Organization{}, ...]

      iex> list_all_organizations(limit: 50, offset: 100)
      [%Organization{}, ...]
  """
  def list_all_organizations(opts \\ []) do
    limit = Keyword.get(opts, :limit, 100)
    offset = Keyword.get(opts, :offset, 0)

    device_count_query =
      from(d in "devices",
        where: d.organization_id == parent_as(:org).id,
        select: count(d.id)
      )

    Organization
    |> from(as: :org)
    |> select_merge([o], %{device_count: subquery(device_count_query)})
    |> order_by([o], desc: o.inserted_at)
    |> limit(^limit)
    |> offset(^offset)
    |> preload(memberships: :user)
    |> Repo.all()
  end

  @doc """
  Returns the total count of organizations in the system.

  ## Examples

      iex> count_organizations()
      15
  """
  def count_organizations do
    Repo.aggregate(Organization, :count)
  end

  @doc """
  Deletes an organization and creates an audit log entry.

  ## Examples

      iex> delete_organization(org_id, superuser_id, "127.0.0.1")
      {:ok, %Organization{}}

      iex> delete_organization(invalid_id, superuser_id, "127.0.0.1")
      ** (Ecto.NoResultsError)
  """
  def delete_organization(org_id, superuser_id, ip_address) do
    with {:ok, org} <- fetch_organization(org_id) do
      do_delete_organization(org, superuser_id, ip_address)
    end
  end

  defp fetch_organization(org_id) do
    case Repo.get(Organization, org_id) do
      nil -> {:error, :not_found}
      org -> {:ok, org}
    end
  end

  defp do_delete_organization(org, superuser_id, ip_address) do
    Repo.transaction(fn ->
      create_audit_log(%{
        action: "org_delete",
        superuser_id: superuser_id,
        target_user_id: nil,
        metadata: %{name: org.name, slug: org.slug},
        ip_address: ip_address
      })

      case Repo.delete(org) do
        {:ok, deleted_org} ->
          deleted_org

        {:error, changeset} ->
          Logger.error("Failed to delete organization: #{inspect(changeset)}")
          Repo.rollback(changeset)
      end
    end)
  end

  @doc """
  Updates billing overrides for an organization with audit logging.

  Only superusers should call this function. Creates an audit log entry
  recording the change.
  """
  def update_billing_overrides(org_id, attrs, superuser_id, ip_address) do
    with {:ok, org} <- fetch_organization(org_id),
         changeset = Organization.billing_override_changeset(org, attrs),
         true <- changeset.valid? do
      do_update_billing_overrides(changeset, org, superuser_id, ip_address)
    else
      {:error, _} = error -> error
      false -> {:error, Organization.billing_override_changeset(%Organization{}, attrs)}
    end
  end

  defp do_update_billing_overrides(changeset, org, superuser_id, ip_address) do
    Repo.transaction(fn ->
      create_audit_log(%{
        action: "org_billing_override_updated",
        superuser_id: superuser_id,
        metadata: %{
          organization_id: org.id,
          organization_name: org.name,
          changes: changeset.changes
        },
        ip_address: ip_address
      })

      case Repo.update(changeset) do
        {:ok, updated_org} ->
          updated_org

        {:error, changeset} ->
          Logger.error("Failed to update billing overrides: #{inspect(changeset.errors)}")
          Repo.rollback(changeset)
      end
    end)
  end

  ## Audit Logging

  @doc """
  Creates an audit log entry.

  ## Examples

      iex> create_audit_log(%{action: "impersonate_start", superuser_id: superuser_id, target_user_id: user_id})
      {:ok, %AuditLog{}}

      iex> create_audit_log(%{action: "invalid"})
      {:error, %Ecto.Changeset{}}
  """
  def create_audit_log(attrs) do
    %AuditLog{}
    |> AuditLog.changeset(attrs)
    |> Repo.insert()
  end

  @doc """
  Lists recent audit logs with associated users.

  ## Options

    * `:limit` - Maximum number of logs to return (default: 100)

  ## Examples

      iex> list_audit_logs()
      [%AuditLog{}, ...]

      iex> list_audit_logs(limit: 50)
      [%AuditLog{}, ...]
  """
  def list_audit_logs(opts \\ []) do
    limit = Keyword.get(opts, :limit, 100)

    AuditLog
    |> order_by([a], desc: a.inserted_at)
    |> limit(^limit)
    |> preload([:superuser, :target_user])
    |> Repo.all()
  end

  @doc """
  Returns audit logs related to a specific user (GDPR data access).
  """
  def list_audit_logs_for_user(user_id, opts \\ []) do
    limit = Keyword.get(opts, :limit, 100)

    AuditLog
    |> where([a], a.target_user_id == ^user_id or a.superuser_id == ^user_id)
    |> order_by([a], desc: a.inserted_at)
    |> limit(^limit)
    |> preload([:superuser, :target_user])
    |> Repo.all()
  end

  ## Global Pricing Management

  @doc """
  Update global pricing settings.

  Creates new Stripe Price if price changed, migrates all active subscriptions,
  updates ApplicationSettings, and creates audit log.

  Returns {:ok, migration_report} or {:error, reason}.
  """
  def update_global_pricing(attrs, superuser_id, ip_address) do
    alias Towerops.Billing
    alias Towerops.Billing.StripeClient
    alias Towerops.Settings
    alias Towerops.Settings.ApplicationSetting

    with {:ok, validated} <- validate_pricing_attrs(attrs),
         old_values = get_current_pricing(),
         {:ok, new_price_id, migration_report} <- maybe_update_stripe_price(validated, old_values),
         :ok <- update_pricing_settings(validated, new_price_id),
         :ok <- create_pricing_audit_log(old_values, validated, migration_report, superuser_id, ip_address) do
      {:ok, migration_report}
    end
  end

  defp validate_pricing_attrs(attrs) do
    free_devices = Map.get(attrs, "default_free_devices")
    price = Map.get(attrs, "default_price_per_device")

    with {:ok, free} <- validate_free_devices(free_devices),
         {:ok, price} <- validate_price(price) do
      {:ok, %{free_devices: free, price: price}}
    end
  end

  defp validate_free_devices(nil), do: {:ok, nil}

  defp validate_free_devices(value) when is_binary(value) do
    case Integer.parse(value) do
      {int, _} when int > 0 and int < 10_000 -> {:ok, int}
      _ -> {:error, :invalid_free_devices}
    end
  end

  defp validate_price(nil), do: {:ok, nil}

  defp validate_price(value) when is_binary(value) do
    case Decimal.parse(value) do
      {decimal, _} ->
        if Decimal.compare(decimal, "0.01") in [:gt, :eq] and
             Decimal.compare(decimal, "999.99") in [:lt, :eq] do
          {:ok, value}
        else
          {:error, :invalid_price}
        end

      :error ->
        {:error, :invalid_price}
    end
  end

  defp get_current_pricing do
    alias Towerops.Settings

    %{
      free_devices: Settings.get_setting("default_free_devices"),
      price: Settings.get_setting("default_price_per_device")
    }
  end

  defp maybe_update_stripe_price(validated, old_values) do
    alias Towerops.Billing
    alias Towerops.Billing.StripeClient

    price_changed = validated.price && validated.price != old_values.price

    if price_changed do
      case StripeClient.create_price(validated.price) do
        {:ok, %{"id" => price_id}} ->
          migration_report = Billing.migrate_all_subscriptions_to_price(price_id)
          {:ok, price_id, migration_report}

        {:error, reason} ->
          {:error, {:stripe_error, reason}}
      end
    else
      {:ok, nil, %{total: 0, succeeded: 0, failed: 0, failures: []}}
    end
  end

  defp update_pricing_settings(validated, new_price_id) do
    alias Towerops.Settings
    alias Towerops.Settings.ApplicationSetting

    if validated.free_devices do
      Settings.update_setting("default_free_devices", validated.free_devices)
    end

    if validated.price do
      Settings.update_setting("default_price_per_device", validated.price)
    end

    if new_price_id do
      # Create setting if doesn't exist
      case Settings.get_setting_record("stripe_price_id") do
        nil ->
          %ApplicationSetting{}
          |> ApplicationSetting.changeset(%{
            key: "stripe_price_id",
            value: new_price_id,
            value_type: "string",
            description: "Current Stripe Price ID for metered billing"
          })
          |> Repo.insert()

        _setting ->
          Settings.update_setting("stripe_price_id", new_price_id)
      end
    end

    :ok
  end

  defp create_pricing_audit_log(old_values, validated, migration_report, superuser_id, ip_address) do
    metadata = %{
      old_free_devices: old_values.free_devices,
      new_free_devices: validated.free_devices,
      old_price: old_values.price,
      new_price: validated.price,
      migration_total: migration_report.total,
      migration_succeeded: migration_report.succeeded,
      migration_failed: migration_report.failed
    }

    create_audit_log(%{
      action: "global_pricing_updated",
      superuser_id: superuser_id,
      ip_address: ip_address,
      metadata: metadata
    })

    :ok
  end
end