package postgres

import (
	"context"
	"errors"
	"fmt"
	"time"

	"github.com/gofrs/uuid/v5"
	"github.com/jmoiron/sqlx"

	"github.com/saveinmed/backend-go/internal/domain"
)

// Repository implements the data access layer using sqlx + pgx.
type Repository struct {
	db *sqlx.DB
}

// New creates a Postgres-backed repository and configures pooling.
func New(db *sqlx.DB) *Repository {
	return &Repository{db: db}
}

func (r *Repository) CreateCompany(ctx context.Context, company *domain.Company) error {
	now := time.Now().UTC()
	company.CreatedAt = now
	company.UpdatedAt = now

	query := `INSERT INTO companies (id, role, cnpj, corporate_name, sanitary_license, created_at, updated_at)
VALUES (:id, :role, :cnpj, :corporate_name, :sanitary_license, :created_at, :updated_at)`

	_, err := r.db.NamedExecContext(ctx, query, company)
	return err
}

func (r *Repository) ListCompanies(ctx context.Context) ([]domain.Company, error) {
	var companies []domain.Company
	query := `SELECT id, role, cnpj, corporate_name, sanitary_license, created_at, updated_at FROM companies ORDER BY created_at DESC`
	if err := r.db.SelectContext(ctx, &companies, query); err != nil {
		return nil, err
	}
	return companies, nil
}

func (r *Repository) CreateProduct(ctx context.Context, product *domain.Product) error {
	now := time.Now().UTC()
	product.CreatedAt = now
	product.UpdatedAt = now

	query := `INSERT INTO products (id, seller_id, name, description, batch, expires_at, price_cents, stock, created_at, updated_at)
VALUES (:id, :seller_id, :name, :description, :batch, :expires_at, :price_cents, :stock, :created_at, :updated_at)`

	_, err := r.db.NamedExecContext(ctx, query, product)
	return err
}

func (r *Repository) ListProducts(ctx context.Context) ([]domain.Product, error) {
	var products []domain.Product
	query := `SELECT id, seller_id, name, description, batch, expires_at, price_cents, stock, created_at, updated_at FROM products ORDER BY created_at DESC`
	if err := r.db.SelectContext(ctx, &products, query); err != nil {
		return nil, err
	}
	return products, nil
}

func (r *Repository) CreateOrder(ctx context.Context, order *domain.Order) error {
	now := time.Now().UTC()
	order.CreatedAt = now
	order.UpdatedAt = now

	tx, err := r.db.BeginTxx(ctx, nil)
	if err != nil {
		return err
	}

	orderQuery := `INSERT INTO orders (id, buyer_id, seller_id, status, total_cents, created_at, updated_at)
VALUES ($1, $2, $3, $4, $5, $6, $7)`
	if _, err := tx.ExecContext(ctx, orderQuery, order.ID, order.BuyerID, order.SellerID, order.Status, order.TotalCents, order.CreatedAt, order.UpdatedAt); err != nil {
		_ = tx.Rollback()
		return err
	}

	itemQuery := `INSERT INTO order_items (id, order_id, product_id, quantity, unit_cents, batch, expires_at) VALUES ($1, $2, $3, $4, $5, $6, $7)`
	for i := range order.Items {
		item := &order.Items[i]
		item.ID = uuid.Must(uuid.NewV7())
		item.OrderID = order.ID
		if _, err := tx.ExecContext(ctx, itemQuery, item.ID, item.OrderID, item.ProductID, item.Quantity, item.UnitCents, item.Batch, item.ExpiresAt); err != nil {
			_ = tx.Rollback()
			return err
		}
	}

	return tx.Commit()
}

func (r *Repository) GetOrder(ctx context.Context, id uuid.UUID) (*domain.Order, error) {
	var order domain.Order
	orderQuery := `SELECT id, buyer_id, seller_id, status, total_cents, created_at, updated_at FROM orders WHERE id = $1`
	if err := r.db.GetContext(ctx, &order, orderQuery, id); err != nil {
		return nil, err
	}

	var items []domain.OrderItem
	itemQuery := `SELECT id, order_id, product_id, quantity, unit_cents, batch, expires_at FROM order_items WHERE order_id = $1`
	if err := r.db.SelectContext(ctx, &items, itemQuery, id); err != nil {
		return nil, err
	}
	order.Items = items
	return &order, nil
}

func (r *Repository) UpdateOrderStatus(ctx context.Context, id uuid.UUID, status domain.OrderStatus) error {
	query := `UPDATE orders SET status = $1, updated_at = $2 WHERE id = $3`
	res, err := r.db.ExecContext(ctx, query, status, time.Now().UTC(), id)
	if err != nil {
		return err
	}
	rows, err := res.RowsAffected()
	if err != nil {
		return err
	}
	if rows == 0 {
		return errors.New("order not found")
	}
	return nil
}

// InitSchema applies a minimal schema for development environments.
func (r *Repository) InitSchema(ctx context.Context) error {
	schema := `
CREATE TABLE IF NOT EXISTS companies (
    id UUID PRIMARY KEY,
    role TEXT NOT NULL,
    cnpj TEXT NOT NULL UNIQUE,
    corporate_name TEXT NOT NULL,
    sanitary_license TEXT NOT NULL,
    created_at TIMESTAMPTZ NOT NULL,
    updated_at TIMESTAMPTZ NOT NULL
);

CREATE TABLE IF NOT EXISTS products (
    id UUID PRIMARY KEY,
    seller_id UUID NOT NULL REFERENCES companies(id),
    name TEXT NOT NULL,
    description TEXT,
    batch TEXT NOT NULL,
    expires_at DATE NOT NULL,
    price_cents BIGINT NOT NULL,
    stock BIGINT NOT NULL,
    created_at TIMESTAMPTZ NOT NULL,
    updated_at TIMESTAMPTZ NOT NULL
);

CREATE TABLE IF NOT EXISTS orders (
    id UUID PRIMARY KEY,
    buyer_id UUID NOT NULL REFERENCES companies(id),
    seller_id UUID NOT NULL REFERENCES companies(id),
    status TEXT NOT NULL,
    total_cents BIGINT NOT NULL,
    created_at TIMESTAMPTZ NOT NULL,
    updated_at TIMESTAMPTZ NOT NULL
);

CREATE TABLE IF NOT EXISTS order_items (
    id UUID PRIMARY KEY,
    order_id UUID NOT NULL REFERENCES orders(id),
    product_id UUID NOT NULL REFERENCES products(id),
    quantity BIGINT NOT NULL,
    unit_cents BIGINT NOT NULL,
    batch TEXT NOT NULL,
    expires_at DATE NOT NULL
);
`

	if _, err := r.db.ExecContext(ctx, schema); err != nil {
		return fmt.Errorf("apply schema: %w", err)
	}
	return nil
}