import pl, { DataFrame } from 'nodejs-polars'
import fs from 'fs'

export function test_x(params: any) {
  const fooSeries = pl.Series("foo", [1, 2, 3])

  let res = fooSeries.sum()

  console.log(res)

  let df = pl.readCSV("data/iris.csv")
}

class CSVDatabase {
  private df: DataFrame | null = null
  private filePath: string

  constructor(filePath: string) {
    this.filePath = filePath
    this.loadCSV()
  }

  private loadCSV() {
    fs.existsSync(this.filePath) ? this.df = pl.readCSV(this.filePath) : this.df = DataFrame([])
  }

  private saveCSV() {
    if (this.df) {
      fs.writeFileSync(this.filePath, this.df.writeCSV())
    }
  }

  create(row: Record<string, any>) {
    if (this.df) {
      this.df = this.df.vstack(DataFrame([row]))
      this.saveCSV()
    }
  }

  read(filter: Record<string, any>) {
    if (this.df) {
      return this.df.filter(filter)
    }
    return null
  }

  update(filter: Record<string, any>, values: Record<string, any>) {
    if (this.df) {
      // this.df = this.df.withColumn(
      //   Object.keys(values)[0],
      //   this.df
      //     .filter(filter)
      //     .withColumn(Object.keys(values)[0], pl.lit(values[Object.keys(values)[0]]))
      // )
      this.saveCSV()
    }
  }

  delete(filter: Record<string, any>) {
    if (this.df) {
      // should be filter Not
      this.df = this.df.filter(filter)
      this.saveCSV()
    }
  }
}