defmodule DaProductApp.Settlements.YspSummary do
  @moduledoc """
  Schema for YSP Summary table that stores settlement summary information
  including file paths and structured settlement data.
  Prevents duplicate settlement processing based on merchant_tag, merchant_id, batch_number, and settlement_date.
  """

  use Ecto.Schema
  import Ecto.Changeset

  @primary_key {:id, :id, autogenerate: true}
  @derive {Phoenix.Param, key: :id}

  schema "ysp_summary" do
    field :merchant_tag, :string
    field :merchant_id, :string
    field :batch_number, :string
    field :settlement_date, :date
    field :file_path, :string
    field :settlement_id, :map

    timestamps(type: :utc_datetime)
  end

  @doc """
  Changeset for creating YSP summary records.
  """
  def changeset(ysp_summary, attrs) do
    ysp_summary
    |> cast(attrs, [
      :merchant_tag,
      :merchant_id,
      :batch_number,
      :settlement_date,
      :file_path,
      :settlement_id
    ])
    |> validate_required([
      :merchant_tag,
      :merchant_id,
      :batch_number,
      :settlement_date,
      :file_path,
      :settlement_id
    ])
    |> validate_length(:merchant_tag, max: 255)
    |> validate_length(:merchant_id, max: 255)
    |> validate_length(:batch_number, max: 50)
    |> unique_constraint([:merchant_tag, :merchant_id, :batch_number, :settlement_date],
      name: :uk_merchant_batch_date,
      message: "Settlement already processed for this merchant, batch, and date"
    )
    # Some databases may have a differently named unique index. Map the other possible
    # constraint name to a changeset error as well to avoid raising Ecto.ConstraintError.
    |> unique_constraint([:merchant_tag, :merchant_id, :batch_number, :settlement_date],
      name: :uk_merchant_batch,
      message: "Settlement already processed for this merchant, batch, and date"
    )
    |> validate_settlement_id_structure()
  end

  @doc """
  Validates the settlement_id JSON structure contains required fields.
  """
  defp validate_settlement_id_structure(changeset) do
    case get_field(changeset, :settlement_id) do
      nil ->
        add_error(changeset, :settlement_id, "is required")

      settlement_data when is_map(settlement_data) ->
        required_keys = ["settlement_reference", "status", "settlement_date"]

        if Enum.all?(required_keys, &Map.has_key?(settlement_data, &1)) do
          changeset
        else
          add_error(
            changeset,
            :settlement_id,
            "must contain required keys: #{Enum.join(required_keys, ", ")}"
          )
        end

      _ ->
        add_error(changeset, :settlement_id, "must be a valid JSON object")
    end
  end

  @doc """
  Creates a standardized settlement_id JSON structure for storage.
  """
  def build_settlement_json(settlement_data) do
    %{
      "settlement_reference" =>
        settlement_data[:settlement_reference] || settlement_data["settlement_reference"] || "",
      "status" => settlement_data[:status] || settlement_data["status"] || "COMPLETED",
      "transaction_count" =>
        settlement_data[:transaction_count] || settlement_data["transaction_count"] || 0,
      "gross_amount" =>
        to_string(settlement_data[:gross_amount] || settlement_data["gross_amount"] || "0.00"),
      "net_amount" =>
        to_string(settlement_data[:net_amount] || settlement_data["net_amount"] || "0.00"),
      "currency" => settlement_data[:currency] || settlement_data["currency"] || "AED",
      "mismatch_detected" =>
        settlement_data[:mismatch_detected] || settlement_data["mismatch_detected"] || false,
      "settlement_date" =>
        to_string(settlement_data[:settlement_date] || settlement_data["settlement_date"]),
      "generated_timestamp" => DateTime.utc_now() |> DateTime.to_iso8601()
    }
  end
end