package mdbc

import (
	"context"
	"errors"
	"fmt"
	"reflect"
	"time"

	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
)

type CountScope struct {
	scope     *Scope
	cw        *ctxWrap
	err       error
	limit     *int64
	skip      *int64
	hint      interface{}
	filter    interface{}
	maxTimeMS *time.Duration
	collation *options.Collation
	opts      *options.CountOptions
	result    int64
}

// SetLimit 设置获取数量
func (cs *CountScope) SetLimit(limit int64) *CountScope {
	cs.limit = &limit
	return cs
}

// SetSkip 设置跳过的数量
func (cs *CountScope) SetSkip(skip int64) *CountScope {
	cs.skip = &skip
	return cs
}

// SetHint 设置hit
func (cs *CountScope) SetHint(hint interface{}) *CountScope {
	if hint == nil {
		cs.hint = bson.M{}
		return cs
	}

	v := reflect.ValueOf(hint)
	if v.Kind() == reflect.Ptr || v.Kind() == reflect.Map || v.Kind() == reflect.Slice {
		if v.IsNil() {
			cs.hint = bson.M{}
		}
	}
	cs.hint = hint
	return cs
}

// SetFilter 设置过滤条件
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
}

// SetMaxTime 设置MaxTime
func (cs *CountScope) SetMaxTime(maxTime time.Duration) *CountScope {
	cs.maxTimeMS = &maxTime
	return cs
}

// SetCollation  设置文档
func (cs *CountScope) SetCollation(collation options.Collation) *CountScope {
	cs.collation = &collation
	return cs
}

// SetContext 设置上下文
func (cs *CountScope) SetContext(ctx context.Context) *CountScope {
	if cs.cw == nil {
		cs.cw = &ctxWrap{}
	}
	cs.cw.ctx = ctx
	return cs
}

func (cs *CountScope) doClear() {
	if cs.cw != nil && cs.cw.cancel != nil {
		cs.cw.cancel()
	}
	cs.scope.execT = 0
	cs.scope.debug = false
}

func (cs *CountScope) getContext() context.Context {
	return cs.cw.ctx
}

// Count 执行计数
func (cs *CountScope) Count() (int64, error) {
	defer cs.doClear()
	cs.doCount()

	if cs.err != nil {
		return 0, cs.err
	}
	return cs.result, nil
}

func (cs *CountScope) optionAssembled() {
	// 配置项被直接调用重写过
	if cs.opts != nil {
		return
	}

	cs.opts = new(options.CountOptions)
	if cs.skip != nil {
		cs.opts.Skip = cs.skip
	}

	if cs.limit != nil {
		cs.opts.Limit = cs.limit
	}

	if cs.collation != nil {
		cs.opts.Collation = cs.collation
	}

	if cs.hint != nil {
		cs.opts.Hint = cs.hint
	}

	if cs.maxTimeMS != nil {
		cs.opts.MaxTime = cs.maxTimeMS
	}
}

func (cs *CountScope) assertErr() {
	if cs.err == nil {
		return
	}
	if errors.Is(cs.err, context.DeadlineExceeded) {
		cs.err = &ErrRequestBroken
		return
	}
	err, ok := cs.err.(mongo.CommandError)
	if !ok {
		return
	}
	if err.HasErrorMessage(context.DeadlineExceeded.Error()) {
		cs.err = &ErrRequestBroken
		return
	}
}

func (cs *CountScope) debug() {
	if !cs.scope.debug {
		return
	}

	debugger := &Debugger{
		collection: cs.scope.tableName,
		execT:      cs.scope.execT,
		action:     cs,
	}
	debugger.String()
}

func (cs *CountScope) doString() string {
	builder := RegisterTimestampCodec(nil).Build()
	filter, _ := bson.MarshalExtJSONWithRegistry(builder, cs.filter, true, true)
	return fmt.Sprintf("count(%s)", string(filter))
}

func (cs *CountScope) doCount() {
	defer cs.assertErr()
	cs.optionAssembled()
	cs.preCheck()
	var starTime time.Time
	if cs.scope.debug {
		starTime = time.Now()
	}
	cs.result, cs.err = db.Collection(cs.scope.tableName).CountDocuments(cs.getContext(), cs.filter, cs.opts)
	if cs.scope.debug {
		cs.scope.execT = time.Since(starTime)
		cs.debug()
	}
}

func (cs *CountScope) preCheck() {
	if cs.filter == nil {
		cs.filter = bson.M{}
	}
	var breakerTTL time.Duration
	if cs.scope.breaker == nil {
		breakerTTL = defaultBreakerTime
	} else if cs.scope.breaker.ttl == 0 {
		breakerTTL = defaultBreakerTime
	} else {
		breakerTTL = cs.scope.breaker.ttl
	}
	if cs.cw == nil {
		cs.cw = &ctxWrap{}
	}
	if cs.cw.ctx == nil {
		cs.cw.ctx, cs.cw.cancel = context.WithTimeout(context.Background(), breakerTTL)
	}
}