package orm

import (
	"context"
	"database/sql"
	"gitee.com/mosache/YFrame/orm/internal/errs"
	model "gitee.com/mosache/YFrame/orm/schema"
)

type Inserter[T any] struct {
	builder

	db *DB

	values []*T

	/// 要插入的列
	columns []string

	/// ON DUPLICATE KEY中使用
	onDuplicateKey *OnDuplicateKey
}

func NewInserter[T any](db *DB) *Inserter[T] {
	return &Inserter[T]{db: db, builder: builder{
		dialect: db.dialect,
		quoter:  db.quoter,
	}}
}

func (i *Inserter[T]) Build() (*Query, error) {
	//var sb strings.Builder

	m, err := i.db.r.Get(new(T))
	if err != nil {
		return nil, err
	}
	i.m = m

	i.sb.WriteString("INSERT INTO")
	i.sb.WriteString(" ")
	i.Quoter(i.m.TableName)

	fields := i.m.Fields
	if len(i.columns) > 0 {
		fields = make([]*model.Field, 0, len(i.columns))
		for _, e := range i.columns {
			field, ok := i.m.FieldMap[e]
			if !ok {
				return nil, errs.NewErrUnknownField(e)
			}

			fields = append(fields, field)
		}
	}

	i.sb.WriteString("(")
	for idx, e := range fields {
		if idx != 0 {
			i.sb.WriteString(",")
		}
		i.sb.WriteString("`")
		i.sb.WriteString(e.ColumnName)
		i.sb.WriteString("`")
	}
	i.sb.WriteString(") ")

	i.sb.WriteString("VALUES ")

	//args := make([]any, 0, len(i.values)*len(i.m.Fields))
	for idx, val := range i.values {
		if idx != 0 {
			i.sb.WriteString(",")
		}
		i.sb.WriteString("(")

		for fIdx, e := range fields {
			if fIdx != 0 {
				i.sb.WriteString(",")
			}
			i.sb.WriteString("?")

			valuer := i.db.creator(i.m, val)

			var arg any
			if arg, err = valuer.Field(e.GoName); err != nil {
				return nil, err
			}

			i.args = append(i.args, arg)
		}

		i.sb.WriteString(")")
	}

	// assigns
	if i.onDuplicateKey != nil {
		if err = i.dialect.BuildOnDuplicateKey(&i.builder, i.onDuplicateKey); err != nil {
			return nil, err
		}
	}
	i.sb.WriteString(";")

	return &Query{
		SQL:  i.sb.String(),
		Args: i.args,
	}, nil
}

func (i *Inserter[T]) Exec(ctx context.Context) Result {
	var (
		r         Result
		q         *Query
		sqlResult sql.Result
		err       error
	)
	q, err = i.Build()
	if err != nil {
		r.Err = err
		return r
	}

	sqlResult, err = i.db.db.ExecContext(ctx, q.SQL, q.Args...)
	if err != nil {
		r.Err = err
		return r
	}
	r.Res = sqlResult

	return r
}