package repository

import (
	"context"
	"errors"

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

	"financeiro-carvalho/internal/middleware"
	"financeiro-carvalho/internal/model"
)

var ErrNotFound = errors.New("not found")

type CategoryRepository interface {
	List(ctx context.Context) ([]model.Category, error)
	GetByID(ctx context.Context, id int) (*model.Category, error)
	Create(ctx context.Context, name, color string, isTax bool) (*model.Category, error)
	Update(ctx context.Context, id int, name, color string, isTax bool) (*model.Category, error)
	Delete(ctx context.Context, id int) error
	HasTransactions(ctx context.Context, id int) (bool, error)
}

type categoryRepo struct{ db *pgxpool.Pool }

func NewCategoryRepository(db *pgxpool.Pool) CategoryRepository {
	return &categoryRepo{db: db}
}

func (r *categoryRepo) List(ctx context.Context) ([]model.Category, error) {
	pid := middleware.ProfileIDFromCtx(ctx)
	rows, err := r.db.Query(ctx, `
		SELECT id, name, color, is_default, is_tax, created_at, updated_at
		FROM categories
		WHERE profile_id = $1
		ORDER BY is_default DESC, name ASC`, pid)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var out []model.Category
	for rows.Next() {
		var c model.Category
		if err := rows.Scan(&c.ID, &c.Name, &c.Color, &c.IsDefault, &c.IsTax, &c.CreatedAt, &c.UpdatedAt); err != nil {
			return nil, err
		}
		out = append(out, c)
	}
	return out, rows.Err()
}

func (r *categoryRepo) GetByID(ctx context.Context, id int) (*model.Category, error) {
	pid := middleware.ProfileIDFromCtx(ctx)
	var c model.Category
	err := r.db.QueryRow(ctx, `
		SELECT id, name, color, is_default, is_tax, created_at, updated_at
		FROM categories WHERE id = $1 AND profile_id = $2`, id, pid).
		Scan(&c.ID, &c.Name, &c.Color, &c.IsDefault, &c.IsTax, &c.CreatedAt, &c.UpdatedAt)
	if errors.Is(err, pgx.ErrNoRows) {
		return nil, ErrNotFound
	}
	return &c, err
}

func (r *categoryRepo) Create(ctx context.Context, name, color string, isTax bool) (*model.Category, error) {
	pid := middleware.ProfileIDFromCtx(ctx)
	var c model.Category
	err := r.db.QueryRow(ctx, `
		INSERT INTO categories (name, color, is_tax, profile_id)
		VALUES ($1, $2, $3, $4)
		RETURNING id, name, color, is_default, is_tax, created_at, updated_at`,
		name, color, isTax, pid).
		Scan(&c.ID, &c.Name, &c.Color, &c.IsDefault, &c.IsTax, &c.CreatedAt, &c.UpdatedAt)
	return &c, err
}

func (r *categoryRepo) Update(ctx context.Context, id int, name, color string, isTax bool) (*model.Category, error) {
	pid := middleware.ProfileIDFromCtx(ctx)
	var c model.Category
	err := r.db.QueryRow(ctx, `
		UPDATE categories
		SET name = $1, color = $2, is_tax = $3, updated_at = NOW()
		WHERE id = $4 AND profile_id = $5
		RETURNING id, name, color, is_default, is_tax, created_at, updated_at`,
		name, color, isTax, id, pid).
		Scan(&c.ID, &c.Name, &c.Color, &c.IsDefault, &c.IsTax, &c.CreatedAt, &c.UpdatedAt)
	if errors.Is(err, pgx.ErrNoRows) {
		return nil, ErrNotFound
	}
	return &c, err
}

func (r *categoryRepo) Delete(ctx context.Context, id int) error {
	pid := middleware.ProfileIDFromCtx(ctx)
	tag, err := r.db.Exec(ctx, `DELETE FROM categories WHERE id = $1 AND profile_id = $2`, id, pid)
	if err != nil {
		return err
	}
	if tag.RowsAffected() == 0 {
		return ErrNotFound
	}
	return nil
}

func (r *categoryRepo) HasTransactions(ctx context.Context, id int) (bool, error) {
	pid := middleware.ProfileIDFromCtx(ctx)
	var count int
	err := r.db.QueryRow(ctx,
		`SELECT COUNT(*) FROM transactions WHERE category_id = $1 AND profile_id = $2`, id, pid).
		Scan(&count)
	return count > 0, err
}