package mdbc

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

	jsoniter "github.com/json-iterator/go"

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

type BulkWriteScope struct {
	scope     *Scope
	cw        *ctxWrap
	err       error
	chunkSize uint32
	opts      *options.BulkWriteOptions
	models    []mongo.WriteModel
	result    *mongo.BulkWriteResult
	chunkFunc func([]mongo.WriteModel) error
}

// doString debug string
func (bws *BulkWriteScope) doString() string {
	var data []interface{}
	builder := RegisterTimestampCodec(nil).Build()
	for _, v := range bws.models {
		var body interface{}
		rawv := Struct2MapOmitEmpty(v)
		b, _ := bson.MarshalExtJSONWithRegistry(builder, rawv, true, true)
		_ = jsoniter.Unmarshal(b, &body)
		data = append(data, body)
	}
	b, _ := jsoniter.Marshal(data)
	return fmt.Sprintf("bulkWrite(%s)", string(b))
}

// debug debug
func (bws *BulkWriteScope) debug() {
	if !bws.scope.debug {
		return
	}

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

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

func (bws BulkWriteScope) getContext() context.Context {
	return bws.cw.ctx
}

// SetBulkWriteOption 设置BulkWriteOption
func (bws *BulkWriteScope) SetBulkWriteOption(opts options.BulkWriteOptions) *BulkWriteScope {
	bws.opts = &opts
	return bws
}

// SetOrdered 设置BulkWriteOptions中的Ordered
func (bws *BulkWriteScope) SetOrdered(ordered bool) *BulkWriteScope {
	if bws.opts == nil {
		bws.opts = new(options.BulkWriteOptions)
	}
	bws.opts.Ordered = &ordered
	return bws
}

// SetChunkSize 指定分块操作大小 默认不分块 当数据足够大时 可能导致deadlock问题？不确定这个问题
func (bws *BulkWriteScope) SetChunkSize(size uint32) *BulkWriteScope {
	bws.chunkSize = size
	return bws
}

// SetChunkFunc 可以在进行批量插入之前做一些事情 若错误将终止这一批数据的写入而执行下一批
func (bws *BulkWriteScope) SetChunkFunc(f func(models []mongo.WriteModel) error) *BulkWriteScope {
	bws.chunkFunc = f
	return bws
}

// SetWriteModel 设置需要操作的数据
func (bws *BulkWriteScope) SetWriteModel(models []mongo.WriteModel) *BulkWriteScope {
	bws.models = models
	return bws
}

// SetWriteModelFunc 可以定义函数来返回需要操作的数据
func (bws *BulkWriteScope) SetWriteModelFunc(f func() []mongo.WriteModel) *BulkWriteScope {
	bws.models = f()
	return bws
}

// preCheck 预检查
func (bws *BulkWriteScope) preCheck() {
	var breakerTTL time.Duration
	if bws.scope.breaker == nil {
		breakerTTL = defaultBreakerTime
	} else if bws.scope.breaker.ttl == 0 {
		breakerTTL = defaultBreakerTime
	} else {
		breakerTTL = bws.scope.breaker.ttl
	}
	if bws.cw == nil {
		bws.cw = &ctxWrap{}
	}
	if bws.cw.ctx == nil {
		bws.cw.ctx, bws.cw.cancel = context.WithTimeout(context.Background(), breakerTTL)
	}
}

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

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

func (bws *BulkWriteScope) doBulkWrite() {
	defer bws.assertErr()
	var starTime time.Time
	if bws.scope.debug {
		starTime = time.Now()
	}
	bws.result, bws.err = db.Collection(bws.scope.tableName).BulkWrite(bws.getContext(), bws.models, bws.opts)
	if bws.scope.debug {
		bws.scope.execT = time.Since(starTime)
		bws.debug()
	}
}

func (bws *BulkWriteScope) splitBulkWrite(arr []mongo.WriteModel, chunkSize int) [][]mongo.WriteModel {
	var newArr [][]mongo.WriteModel
	for i := 0; i < len(arr); i += chunkSize {
		end := i + chunkSize

		if end > len(arr) {
			end = len(arr)
		}

		newArr = append(newArr, arr[i:end])
	}

	return newArr
}

func (bws *BulkWriteScope) checkModel() {
	if len(bws.models) == 0 {
		bws.err = fmt.Errorf("models empty")
		return
	}
	// 命令检测
}

// Do 执行批量操作 请确保 SetWriteModel 已被设置 否则报错
func (bws *BulkWriteScope) Do() (*mongo.BulkWriteResult, error) {
	defer bws.doClear()
	bws.checkModel()
	bws.preCheck()

	if bws.err != nil {
		return nil, bws.err
	}

	// 如果设置了chunkSize就分片插入
	if bws.chunkSize > 0 {
		models := bws.splitBulkWrite(bws.models, int(bws.chunkSize))
		for _, model := range models {
			bws.models = model
			if bws.chunkFunc != nil {
				if bws.err = bws.chunkFunc(bws.models); bws.err != nil {
					continue
				}
			}
			bws.doBulkWrite()
		}
	} else {
		bws.doBulkWrite()
	}

	if bws.err != nil {
		return nil, bws.err
	}

	return bws.result, nil
}