defmodule ProviderService.Projections.ProviderProjection do
  use Commanded.Projections.Ecto,
    application: ProviderService.CommandedApp,
    repo: ProviderService.Repo,
    name: "ProviderProjection",
    consistency: :strong

  alias ProviderService.Events.{
    ProviderRegistered,
    ProviderUpdated,
    ProviderDeactivated,
    ProviderReactivated,
    ProviderTemplateAdded,
    ProviderTemplateActivated,
    ProviderTemplateDeactivated,
    ProviderTemplateDefaultSet,
    ProviderTemplateRemoved
  }

  alias ProviderService.Projections.Provider
  import Ecto.Query

  project(%ProviderRegistered{} = e, _meta, fn multi ->
    Ecto.Multi.insert(multi, :provider, %Provider{
      provider_id: e.provider_id,
      name: e.name,
      email: e.email,
      phone: e.phone,
      contact_name: e.contact_name,
      ruc: e.ruc,
      address: e.address,
      active: true,
      templates: %{},
      default_templates: %{}
    })
  end)

  project(%ProviderUpdated{} = e, _meta, fn multi ->
    multi
    |> Ecto.Multi.run(:fetch, fn repo, _ -> {:ok, repo.get!(Provider, e.provider_id)} end)
    |> Ecto.Multi.update(:provider, fn %{fetch: p} ->
      Ecto.Changeset.change(p,
        name: e.name,
        email: e.email,
        phone: e.phone,
        contact_name: e.contact_name,
        ruc: e.ruc,
        address: e.address
      )
    end)
  end)

  project(%ProviderDeactivated{} = e, _meta, fn multi ->
    multi
    |> Ecto.Multi.run(:fetch, fn repo, _ -> {:ok, repo.get!(Provider, e.provider_id)} end)
    |> Ecto.Multi.update(:provider, fn %{fetch: p} ->
      Ecto.Changeset.change(p, active: false)
    end)
  end)

  project(%ProviderReactivated{} = e, _meta, fn multi ->
    multi
    |> Ecto.Multi.run(:fetch, fn repo, _ -> {:ok, repo.get!(Provider, e.provider_id)} end)
    |> Ecto.Multi.update(:provider, fn %{fetch: p} ->
      Ecto.Changeset.change(p, active: true)
    end)
  end)

  # templates:         %{ policy_type => %{ client_type => [template] } }
  # default_templates: %{ policy_type => %{ client_type => template_id } }

  project(%ProviderTemplateAdded{} = e, _meta, fn multi ->
    multi
    |> Ecto.Multi.run(:fetch, fn repo, _ -> {:ok, repo.get!(Provider, e.provider_id)} end)
    |> Ecto.Multi.update(:provider, fn %{fetch: p} ->
      template = %{
        "template_id" => e.template_id,
        "client_type" => e.client_type,
        "document_url" => e.document_url,
        "active" => false
      }

      updated =
        p.templates
        |> Map.update(e.policy_type, %{e.client_type => [template]}, fn inner ->
          Map.update(inner, e.client_type, [template], fn list -> list ++ [template] end)
        end)

      Ecto.Changeset.change(p, templates: updated)
    end)
  end)

  project(%ProviderTemplateActivated{} = e, _meta, fn multi ->
    multi
    |> Ecto.Multi.run(:fetch, fn repo, _ -> {:ok, repo.get!(Provider, e.provider_id)} end)
    |> Ecto.Multi.update(:provider, fn %{fetch: p} ->
      updated =
        update_template_field(
          p.templates,
          e.policy_type,
          e.client_type,
          e.template_id,
          "active",
          true
        )

      Ecto.Changeset.change(p, templates: updated)
    end)
  end)

  project(%ProviderTemplateDeactivated{} = e, _meta, fn multi ->
    multi
    |> Ecto.Multi.run(:fetch, fn repo, _ -> {:ok, repo.get!(Provider, e.provider_id)} end)
    |> Ecto.Multi.update(:provider, fn %{fetch: p} ->
      updated =
        update_template_field(
          p.templates,
          e.policy_type,
          e.client_type,
          e.template_id,
          "active",
          false
        )

      template_id = e.template_id

      default_templates =
        case get_in(p.default_templates, [e.policy_type, e.client_type]) do
          ^template_id ->
            Map.update(p.default_templates, e.policy_type, %{}, &Map.delete(&1, e.client_type))

          _ ->
            p.default_templates
        end

      Ecto.Changeset.change(p, templates: updated, default_templates: default_templates)
    end)
  end)

  project(%ProviderTemplateDefaultSet{} = e, _meta, fn multi ->
    multi
    |> Ecto.Multi.run(:fetch, fn repo, _ -> {:ok, repo.get!(Provider, e.provider_id)} end)
    |> Ecto.Multi.update(:provider, fn %{fetch: p} ->
      default_templates =
        p.default_templates
        |> Map.update(e.policy_type, %{e.client_type => e.template_id}, fn inner ->
          Map.put(inner, e.client_type, e.template_id)
        end)

      Ecto.Changeset.change(p, default_templates: default_templates)
    end)
  end)

  project(%ProviderTemplateRemoved{} = e, _meta, fn multi ->
    multi
    |> Ecto.Multi.run(:fetch, fn repo, _ -> {:ok, repo.get!(Provider, e.provider_id)} end)
    |> Ecto.Multi.update(:provider, fn %{fetch: p} ->
      updated =
        p.templates
        |> Map.update(e.policy_type, %{}, fn inner ->
          Map.update(inner, e.client_type, [], fn list ->
            Enum.reject(list, &(&1["template_id"] == e.template_id))
          end)
        end)

      template_id = e.template_id

      default_templates =
        case get_in(p.default_templates, [e.policy_type, e.client_type]) do
          ^template_id ->
            Map.update(p.default_templates, e.policy_type, %{}, &Map.delete(&1, e.client_type))

          _ ->
            p.default_templates
        end

      Ecto.Changeset.change(p, templates: updated, default_templates: default_templates)
    end)
  end)

  # ---------------------------------------------------------------------------
  # Helpers
  # ---------------------------------------------------------------------------

  defp update_template_field(templates, policy_type, client_type, template_id, field, value) do
    Map.update(templates, policy_type, %{}, fn inner ->
      Map.update(inner, client_type, [], fn list ->
        Enum.map(list, fn t ->
          if t["template_id"] == template_id, do: Map.put(t, field, value), else: t
        end)
      end)
    end)
  end
end