package model

import (
	"context"
	"errors"
	"time"

	mysqldriver "github.com/go-sql-driver/mysql"
	"gorm.io/gorm"

	"spark-server/internal/module/message/entity"
	"spark-server/internal/pkg/errs"
)

// Repo is MySQL persistence for messages.
type Repo struct {
	gdb *gorm.DB
}

func NewRepo(gdb *gorm.DB) *Repo {
	return &Repo{gdb: gdb}
}

func (m *Repo) session(ctx context.Context) (*gorm.DB, error) {
	if m == nil || m.gdb == nil {
		return nil, errs.ErrAvailable
	}
	return m.gdb.WithContext(ctx), nil
}

func mapDBErr(err error) error {
	if err == nil {
		return nil
	}
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return errs.ErrNotFound
	}
	var me *mysqldriver.MySQLError
	if errors.As(err, &me) && me.Number == 1062 {
		return errs.ErrDuplicate
	}
	return errs.ErrInner.WithError("message-mysql", err)
}

func (m *Repo) GetByID(ctx context.Context, id int64) (*entity.Message, error) {
	if id <= 0 {
		return nil, errs.ErrInvalidArgument
	}
	db, err := m.session(ctx)
	if err != nil {
		return nil, err
	}
	var row Message
	if err := db.Where("id = ?", id).Take(&row).Error; err != nil {
		return nil, mapDBErr(err)
	}
	return row.Entity(), nil
}

func (m *Repo) Create(ctx context.Context, message *entity.Message) error {
	if message == nil || message.ID <= 0 {
		return errs.ErrInvalidArgument
	}
	db, err := m.session(ctx)
	if err != nil {
		return err
	}
	row := FromEntity(message)
	if message.CreatedAtMS > 0 {
		row.CreatedAt = time.UnixMilli(message.CreatedAtMS)
	} else {
		row.CreatedAt = time.Now()
	}
	return mapDBErr(db.Create(row).Error)
}