import pl, { DataFrame } from 'nodejs-polars'
import fs, { writeFile } 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>) {
    return this.df ? this.df.filter(filter) : null
  }

  update(filter: Record<string, any>, values: Record<string, any>) {
    if (this.df) {
      // update it
      this.saveCSV()
    }
  }

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

// A CSV can refer to other CSV's via pointers, a type of metadata

interface CSVDatabase2 {
  df: DataFrame
  filepath: string
}

export function create_csv_database(filepath: string): CSVDatabase2 {
  // let df = DataFrame([], { columns: ["key", "value"] })
  let df = DataFrame({ "key": ['header'], "value": ['next'] })

  // writeFile(filepath, 'key,value\nheader,next', () => { })
  // let df = pl.readCSV(filepath)
  df.writeCSV(filepath)

  return { df, filepath }
}

export function save_db(db: CSVDatabase2) {
  db.df.writeCSV(db.filepath)
}

export function add_row(db: CSVDatabase2, row: Record<string, string>) {
  db.df = db.df.vstack(DataFrame(row))
}

export function print_head(db: CSVDatabase2) {
  console.log(db.df.head())
}

// can filter everything that is not the row, and do to db

export function delete_row_by_key({df, filepath}: CSVDatabase2, key: string) {
  // db.df.drop(pl.col("key").eq(key))
  // df = df.select((pl.col("key") != key).alias("nrs > 1"))
  // db.df = db.df.filter(pl.col("key").neq(key))
}