// Copyright 2023 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package asyncloaddata

import (
	"encoding/json"

	"go.uber.org/atomic"
)

// Progress is the progress of the LOAD DATA task.
type Progress struct {
	// SourceFileSize is the size of the source file in bytes. When we can't get
	// the size of the source file, it will be set to -1.
	// Currently the value is read by seek(0, end), when LOAD DATA LOCAL we wrap
	// SimpleSeekerOnReadCloser on MySQL client connection which doesn't support
	// it.
	SourceFileSize int64
	// LoadedFileSize is the size of the data that will be loaded in bytes. It's
	// larger than the actual loaded data size, but due to the fact that reading
	// is once-a-block and a block may generate multiple tasks that are
	// concurrently executed, we can't know the actual loaded data size easily.
	LoadedFileSize *atomic.Int64
	// LoadedRowCnt is the number of rows that has been loaded.
	LoadedRowCnt *atomic.Uint64
}

// NewProgress creates a new Progress.
func NewProgress() *Progress {
	return &Progress{
		SourceFileSize: -1,
		LoadedFileSize: atomic.NewInt64(0),
		LoadedRowCnt:   atomic.NewUint64(0),
	}
}

// String implements the fmt.Stringer interface.
func (p *Progress) String() string {
	bs, _ := json.Marshal(p)
	return string(bs)
}

// ProgressFromJSON creates a Progress from a JSON string.
func ProgressFromJSON(bs []byte) (*Progress, error) {
	var p Progress
	err := json.Unmarshal(bs, &p)
	return &p, err
}