package mdbc

import (
	"context"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo/options"
	"reflect"
)

type countScope struct {
	scope  *scope
	mdbc   *mdbc
	ctx    context.Context
	limit  int64
	skip   int64
	filter interface{}
	opts   options.CountOptions
}

// SetContext set operate context, default timeout 30s
func (cs *countScope) SetContext(ctx context.Context) *countScope {
	cs.ctx = ctx
	return cs
}

// SetLimit set filter limit size
func (cs *countScope) SetLimit(limit int64) *countScope {
	cs.limit = limit
	return cs
}

// SetSkip set filter skip size
func (cs *countScope) SetSkip(skip int64) *countScope {
	cs.skip = skip
	return cs
}

func (cs *countScope) SetFilter(filter interface{}) *countScope {
	if filter == nil {
		cs.filter = bson.M{}
		return cs
	}
	v := reflect.ValueOf(filter)
	if v.Kind() == reflect.Ptr || v.Kind() == reflect.Map || v.Kind() == reflect.Slice {
		if v.IsNil() {
			cs.filter = bson.M{}
		}
	}
	cs.filter = filter
	return cs
}

func (cs *countScope) mergeOptions() {
	if cs.ctx == nil {
		cs.ctx = context.Background()
	}
	if cs.filter == nil {
		cs.filter = bson.M{}
	}
	if cs.skip != 0 {
		cs.opts.Skip = &cs.skip
	}
	if cs.limit != 0 {
		cs.opts.Limit = &cs.limit
	}
}

func (cs *countScope) Count() (int64, error) {
	cs.mergeOptions()
	return cs.mdbc.database.Collection(cs.scope.tableName).CountDocuments(cs.ctx, cs.filter, &cs.opts)
}