package repository

import (
	"context"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"

	"git.sundynix.cn/Blizzard/Veyra/internal/apperror"
	"git.sundynix.cn/Blizzard/Veyra/internal/model"
)

type AccountRepository struct{ pool *pgxpool.Pool }

func NewAccountRepository(pool *pgxpool.Pool) *AccountRepository {
	return &AccountRepository{pool: pool}
}

func (r *AccountRepository) Create(ctx context.Context, a model.Account, entry *model.CashEntry) (model.AccountSummary, error) {
	tx, err := r.pool.Begin(ctx)
	if err != nil {
		return model.AccountSummary{}, apperror.ErrUnavailable
	}
	defer tx.Rollback(context.Background())
	// Lock the owner so account creation cannot race with disabling the user.
	var status string
	if err := tx.QueryRow(ctx, `SELECT status FROM veyra_user WHERE id=$1 AND role='USER' FOR UPDATE`, a.UserID).Scan(&status); err != nil {
		return model.AccountSummary{}, mapError(err)
	}
	if status != "ACTIVE" {
		return model.AccountSummary{}, apperror.ErrForbidden
	}
	err = tx.QueryRow(ctx, `INSERT INTO veyra_account(id,user_id,mode,name,currency,ledger_status) VALUES($1,$2,$3,$4,$5,$6) RETURNING created_at`, a.ID, a.UserID, a.Mode, a.Name, a.Currency, a.LedgerStatus).Scan(&a.CreatedAt)
	if err != nil {
		return model.AccountSummary{}, mapError(err)
	}
	var balance *string
	if entry != nil {
		if _, err := tx.Exec(ctx, `INSERT INTO veyra_cash_entry(id,account_id,entry_type,amount_minor) VALUES($1,$2,$3,$4)`, entry.ID, entry.AccountID, entry.EntryType, entry.AmountMinor); err != nil {
			return model.AccountSummary{}, mapError(err)
		}
		value := model.FormatMoney(entry.AmountMinor)
		balance = &value
	}
	if err := tx.Commit(ctx); err != nil {
		return model.AccountSummary{}, apperror.ErrUnavailable
	}
	return model.AccountSummary{Account: a, CashBalance: balance}, nil
}

const summarySelect = `SELECT a.id,a.user_id,a.mode,a.name,a.currency,a.ledger_status,a.created_at,CASE WHEN a.ledger_status='COMPLETE' THEN (SELECT COALESCE(sum(e.amount_minor),0)::bigint FROM veyra_cash_entry e WHERE e.account_id=a.id) ELSE NULL END FROM veyra_account a`

func scanSummary(row pgx.Row) (model.AccountSummary, error) {
	var s model.AccountSummary
	var minor *int64
	err := row.Scan(&s.ID, &s.UserID, &s.Mode, &s.Name, &s.Currency, &s.LedgerStatus, &s.CreatedAt, &minor)
	if err != nil {
		return s, mapError(err)
	}
	if minor != nil {
		value := model.FormatMoney(*minor)
		s.CashBalance = &value
	}
	return s, nil
}

func (r *AccountRepository) Get(ctx context.Context, userID, accountID string) (model.AccountSummary, error) {
	return scanSummary(r.pool.QueryRow(ctx, summarySelect+` WHERE a.user_id=$1 AND a.id=$2`, userID, accountID))
}

func (r *AccountRepository) List(ctx context.Context, userID string) ([]model.AccountSummary, error) {
	rows, err := r.pool.Query(ctx, summarySelect+` WHERE a.user_id=$1 ORDER BY a.created_at,a.id`, userID)
	if err != nil {
		return nil, apperror.ErrUnavailable
	}
	defer rows.Close()
	list := make([]model.AccountSummary, 0)
	for rows.Next() {
		s, err := scanSummary(rows)
		if err != nil {
			return nil, err
		}
		list = append(list, s)
	}
	return list, mapError(rows.Err())
}