defmodule DaProductApp.Transactions.PosTransaction do
  @moduledoc """
  POS Transaction schema - Main transaction records.
  
  Ported from Java entity: org.jpos.tcpay.db.entity.PosTransaction
  Stores completed/processed transactions from all networks (YSP, VISA, MasterCard, etc.)
  
  Elixir best practices applied:
  - Uses Elixir naming conventions (snake_case)
  - Leverages Ecto changesets for validation
  - Implements proper associations
  - Uses Phoenix.Param for URL generation
  """
  
  use Ecto.Schema
  import Ecto.Changeset
  
  alias DaProductApp.YSP.AcquirerTerminal
  
  # Configure auto-increment primary key for MySQL
  @primary_key {:id, :id, autogenerate: true}
  @derive {Phoenix.Param, key: :id}

  schema "pos_transaction" do
    # Switch-side identifiers (what POS sends)
    field :s_tid, :string               # Switch Terminal ID
    field :s_mid, :string               # Switch Merchant ID  
    field :s_tid_stan, :string          # Switch STAN
    field :s_tid_invoice_no, :string    # Switch Invoice Number
    field :s_tid_batch_no, :string      # Switch Batch Number
    
    # Backend-side identifiers (what we send to acquirer)
    field :b_tid, :string               # Backend Terminal ID
    field :b_mid, :string               # Backend Merchant ID
    # acquirer_id is defined by belongs_to association below
    field :b_tid_stan, :string          # Backend STAN
    field :b_tid_invoice_no, :string    # Backend Invoice Number
    field :b_tid_batch_no, :string      # Backend Batch Number
    field :b_tid_date, :string          # Backend Transaction Date (YYYYMMDD)
    field :b_tid_time, :string          # Backend Transaction Time (HHMMSS)
    
    # Transaction details
    field :entry_mode, :string          # Card entry mode (swipe, chip, manual, etc.)
    field :condition_code, :string      # POS condition code
    field :currency_code, :string       # Transaction currency (ISO 4217)
    field :mti, :string                 # Message Type Indicator
    field :proc_code, :string           # Processing code
    
    # Amounts (stored as integers in minor units, e.g., cents)
    field :total_amount, :decimal       # Total transaction amount
    field :auth_amount, :decimal        # Authorized amount
    field :cash_amount, :decimal        # Cash back amount
    field :tip_amount, :decimal         # Tip amount
    
    # Response data
    field :approval_code, :string       # Authorization code
    field :reference_no, :string        # Reference number (RRN)
    field :response_code, :string       # Response code (00=approved, etc.)
    field :response_message, :string    # Response message text
    
    # Card data (encrypted/masked)
    field :masked_pan, :string          # Masked PAN for display
    field :card_holder_name, :string    # Cardholder name
    field :expiry_date, :string         # Card expiry (YYMM)
    field :card_brand, :string          # Card brand (VISA, MC, AMEX, etc.)
    
    # Security and tracking
    field :track2_data_hash, :string    # Hashed track 2 data (for duplicate detection)
    field :pin_verified, :boolean       # PIN verification result
    field :signature_required, :boolean # Signature required flag
    
    # Processing metadata
    field :processing_time, :integer    # Processing time in milliseconds
    field :retry_count, :integer        # Number of retry attempts
    field :original_mti, :string        # Original MTI (for reversals/adjustments)
    
    # Status tracking  
    field :status, :string              # Transaction status
    field :settled, :boolean, default: false    # Settlement status
    field :settled_at, :utc_datetime    # Settlement timestamp
    
    # Associations
    belongs_to :acquirer_terminal, AcquirerTerminal, foreign_key: :acquirer_id, references: :id

    timestamps()
  end

  @doc false
  def changeset(pos_transaction, attrs) do
    pos_transaction
    |> cast(attrs, [
      :s_tid, :s_mid, :s_tid_stan, :s_tid_invoice_no, :s_tid_batch_no,
      :b_tid, :b_mid, :b_tid_stan, :b_tid_invoice_no,
      :b_tid_batch_no, :b_tid_date, :b_tid_time, :entry_mode, :condition_code,
      :currency_code, :mti, :proc_code, :total_amount, :auth_amount,
      :cash_amount, :tip_amount, :approval_code, :reference_no,
      :response_code, :response_message, :masked_pan, :card_holder_name,
      :expiry_date, :card_brand, :track2_data_hash, :pin_verified,
      :signature_required, :processing_time, :retry_count, :original_mti,
      :status, :settled, :settled_at
    ])
    |> validate_required([
      :s_tid, :s_mid, :mti, :proc_code, :total_amount, :currency_code, :status
    ])
    |> validate_inclusion(:status, ["PENDING", "APPROVED", "DECLINED", "REVERSED", "SETTLED"])
    |> validate_inclusion(:mti, ["0100", "0110", "0200", "0210", "0400", "0410", "0420", "0430"])
    |> validate_length(:s_tid, max: 8)
    |> validate_length(:s_mid, max: 15)
    |> validate_length(:response_code, is: 2)
    |> validate_number(:total_amount, greater_than_or_equal_to: 0)
    |> foreign_key_constraint(:acquirer_id)
  end
  
  @doc """
  Creates a changeset for marking transaction as settled.
  """
  def settle_changeset(pos_transaction, attrs \\ %{}) do
    pos_transaction
    |> cast(attrs, [:settled, :settled_at])
    |> put_change(:settled, true)
    |> put_change(:settled_at, DateTime.utc_now())
  end
  
  @doc """
  Creates a changeset for updating transaction status.
  """
  def status_changeset(pos_transaction, status) when is_binary(status) do
    pos_transaction
    |> cast(%{status: status}, [:status])
    |> validate_required([:status])
    |> validate_inclusion(:status, ["PENDING", "APPROVED", "DECLINED", "REVERSED", "SETTLED"])
  end
end