package types

import (
	"time"

	"github.com/google/uuid"
)

// At the center of the application is the transaction.
//
// Every piece of data should be calculated based on transactions. This means potential calculation errors can be fixed later in time.
//
// If it becomes necessary to precalculate snapshots for performance reasons, this can be done in the future. But the transaction should always be the source of truth.
type Transaction struct {
	Id      uuid.UUID
	GroupId uuid.UUID

	AccountId uuid.UUID
	// nil indicates that the transaction is not yet associated with a piggy bank
	PiggyBankId *uuid.UUID

	// The internal transaction is amove between e.g. an account and a piggy bank to execute a savings plan
	Internal bool

	// The value of the transacion. Negative for outgoing and positive for incoming
	Value     int64
	Timestamp time.Time

	Note string

	CreatedAt time.Time
	// either "<username>" or "system-<subsystem>"
	CreatedBy uuid.UUID
	UpdatedAt time.Time
	UpdatedBy uuid.UUID
}

// The Account holds money
type Account struct {
	Id      uuid.UUID
	GroupId uuid.UUID `db:"group_id"`

	// Custom Name of the account, e.g. "Bank", "Cash", "Credit Card"
	Name string

	CurrentBalance  int64      `db:"current_balance"`
	LastTransaction *time.Time `db:"last_transaction"`
	// The current precalculated value of:
	// 	Account.Balance - [PiggyBank.Balance...]
	OinkBalance int64 `db:"oink_balance"`

	CreatedAt time.Time  `db:"created_at"`
	CreatedBy uuid.UUID  `db:"created_by"`
	UpdatedAt *time.Time `db:"updated_at"`
	UpdatedBy *uuid.UUID `db:"updated_by"`
}

// The PiggyBank is a fictional account. The money it "holds" is actually in the Account
type PiggyBank struct {
	Id      uuid.UUID
	GroupId uuid.UUID

	AccountId uuid.UUID
	Name      string

	CurrentBalance int64

	CreatedAt time.Time
	CreatedBy uuid.UUID
	UpdatedAt *time.Time
	UpdatedBy *uuid.UUID
}

// The SavingsPlan is applied every interval to the PiggyBank/Account as a transaction
type SavingsPlan struct {
	Id      uuid.UUID
	GroupId uuid.UUID

	PiggyBankId uuid.UUID

	MonthlySaving int64

	ValidFrom time.Time
	/// nil means it is valid indefinitely
	ValidTo *time.Time

	CreatedAt time.Time
	CreatedBy uuid.UUID
	UpdatedAt *time.Time
	UpdatedBy *uuid.UUID
}