package repository

import (
	"context"
	"errors"
	"git.sch9.ru/new_gate/ms-tester/internal/models"
	"git.sch9.ru/new_gate/ms-tester/pkg/utils"
	"github.com/jackc/pgerrcode"
	"github.com/jackc/pgx/v5/pgconn"
	"github.com/jmoiron/sqlx"
	"go.uber.org/zap"
)

type ProblemRepository struct {
	db     *sqlx.DB
	logger *zap.Logger
}

func NewProblemRepository(db *sqlx.DB, logger *zap.Logger) *ProblemRepository {
	return &ProblemRepository{
		db:     db,
		logger: logger,
	}
}

const createProblemQuery = "INSERT INTO problems (title) VALUES (?) RETURNING id"

func (r *ProblemRepository) CreateProblem(ctx context.Context, title string) (int32, error) {
	query := r.db.Rebind(createProblemQuery)
	rows, err := r.db.QueryxContext(ctx, query, title)
	if err != nil {
		return 0, handlePgErr(err)
	}

	defer rows.Close()
	var id int32
	rows.Next()
	err = rows.Scan(&id)
	if err != nil {
		return 0, handlePgErr(err)
	}

	return id, nil
}

const readProblemQuery = "SELECT * from problems WHERE id=? LIMIT 1"

func (r *ProblemRepository) ReadProblemById(ctx context.Context, id int32) (*models.Problem, error) {
	var problem models.Problem
	query := r.db.Rebind(readProblemQuery)
	err := r.db.GetContext(ctx, &problem, query, id)
	if err != nil {
		return nil, handlePgErr(err)
	}
	return &problem, nil
}

const deleteProblemQuery = "DELETE FROM problems WHERE id=?"

func (r *ProblemRepository) DeleteProblem(ctx context.Context, id int32) error {
	query := r.db.Rebind(deleteProblemQuery)
	_, err := r.db.ExecContext(ctx, query, id)
	if err != nil {
		return handlePgErr(err)
	}

	return nil
}

func handlePgErr(err error) error {
	var pgErr *pgconn.PgError
	if !errors.As(err, &pgErr) {
		return utils.StorageError(err, utils.ErrUnknown, "unexpected error from postgres")
	}
	if pgerrcode.IsIntegrityConstraintViolation(pgErr.Code) {
		// TODO: probably should specify which constraint
		return utils.StorageError(err, utils.ErrConflict, pgErr.Message)
	}
	if pgerrcode.IsNoData(pgErr.Code) {
		return utils.StorageError(err, utils.ErrNotFound, pgErr.Message)
	}
	return utils.StorageError(err, utils.ErrUnimplemented, "unimplemented error")
}