package csv

import (
	"encoding/csv"
	"errors"
	"gitee.com/lllgo/gopkg/log"
	"os"
)

// csv操作封装 为了便于操作 数据采用map存储
type Table struct {
	//文件路径
	FileName string
	//数据开始行，值从0开始 默认1  第一行一般为列名
	StartRow int
	//数据对象转换为csv字符串数组
	recordToCsv RecordToCsvFunc
	//csv字符串数组转换为数据对象
	csvSliceToRecord CsvSliceToRecordFunc

	Comma, Comment rune
	UseCRLF        bool

	file *os.File
	//存储数据记录
	dataRecords    []Record
	cacheMeta      []Meta
	notDataRecords [][]string
	needRead       bool
}
type Meta struct {
	Id int
}
type Record interface{}
type RecordToCsvFunc func(r Record, m Meta) []string
type CsvSliceToRecordFunc func(v []string, m Meta) Record

func NewTable(filename string, f1 RecordToCsvFunc, f2 CsvSliceToRecordFunc) *Table {
	flag := os.O_RDWR | os.O_CREATE | os.O_SYNC

	file, err := os.OpenFile(filename, flag, 0666)
	if err != nil {
		log.Error(err)
		return nil
	}

	return &Table{
		FileName:         filename,
		StartRow:         1,
		file:             file,
		Comma:            ',',
		recordToCsv:      f1,
		csvSliceToRecord: f2,
		cacheMeta:        make([]Meta, 0),
		needRead:         true,
	}
}

// 读取所有数据
func (t *Table) Read() error {

	if !t.needRead {
		return nil
	}

	reader := csv.NewReader(t.file)
	if reader == nil {
		return errors.New("NewReader return nil, file:" + t.FileName)
	}

	reader.Comma = t.Comma
	reader.Comment = t.Comment

	records, err := reader.ReadAll()
	if err != nil {
		return err
	}

	if len(records) < t.StartRow {
		return errors.New(t.FileName + " is empty")
	}

	var allRecords []Record
	for i := t.StartRow; i < len(records); i++ {
		meta := Meta{Id: i - t.StartRow + 1}
		r := t.csvSliceToRecord(records[i], meta)
		allRecords = append(allRecords, r)
		t.cacheMeta = append(t.cacheMeta, meta)
	}

	t.dataRecords = allRecords
	t.notDataRecords = records[0:t.StartRow]

	t.needRead = false

	return nil
}

// 按条件查找记录
func (t *Table) GetRecords(cond ...func(r Record, m Meta) bool) []Record {
	rs, _ := t.GetRecordsAndMeta(cond...)
	return rs
}

// 按条件查找记录
func (t *Table) GetRecordsAndMeta(cond ...func(r Record, m Meta) bool) (rs []Record, ms []Meta) {

	if len(cond) == 0 {
		return t.dataRecords, t.cacheMeta
	}

	lc := len(cond) - 1
	for i, r := range t.dataRecords {
		for j, c := range cond {
			if !c(r, t.cacheMeta[i]) {
				continue
			}
			if lc == j {
				rs = append(rs, r)
				ms = append(ms, t.cacheMeta[i])
			}
		}
	}
	return
}

// 按条件更新记录
func (t *Table) SetRecordByCond(new Record, cond ...func(r Record, m Meta) bool) error {
	lc := len(cond) - 1
	for i, r := range t.dataRecords {
		for j, c := range cond {
			if !c(r, t.cacheMeta[i]) {
				continue
			}
			if lc == j {
				t.dataRecords[i] = new
			}
		}
	}
	return t.WriteAll()
}

// 按ID更新记录
func (t *Table) SetRecordById(new Record, id int) error {
	t.dataRecords[getIndexById(id)] = new
	return t.WriteAll()
}

// 按ID更新记录
func (t *Table) RemoveRecordById(id int) error {
	t.dataRecords = t.dataRecords[0:getIndexById(id)]
	t.dataRecords = append(t.dataRecords, t.dataRecords[id:])
	return t.WriteAll()
}

// 重置所有数据
func (t *Table) WriteAll() error {

	//清空旧文件
	if err := t.file.Truncate(0); err != nil {
		return err
	}
	if _, err := t.file.Seek(0, 0); err != nil {
		return err
	}

	csvRecords := t.notDataRecords
	for i, record := range t.dataRecords {
		csvRecords = append(csvRecords, t.recordToCsv(record, t.cacheMeta[i]))
	}

	return t.getWriter().WriteAll(csvRecords)
}

func (t *Table) getWriter() *csv.Writer {
	writer := csv.NewWriter(t.file)
	writer.Comma = t.Comma
	writer.UseCRLF = t.UseCRLF
	return writer
}

// 添加记录
func (t *Table) Insert(record Record) error {
	t.dataRecords = append(t.dataRecords, record)
	meta := Meta{Id: len(t.dataRecords)}
	t.cacheMeta = append(t.cacheMeta, meta)
	writer := t.getWriter()
	if err := writer.Write(t.recordToCsv(record, meta)); err != nil {
		return err
	}
	writer.Flush()
	return nil
}

func getIndexById(id int) int {
	return id - 1
}