import React from "react"
import Select from "@mui/material/Select"
import MenuItem from "@mui/material/MenuItem"
import ListSubheader from "@mui/material/ListSubheader"
import FormControl from "@mui/material/FormControl"
import InputLabel from "@mui/material/InputLabel"

export default (props) => {
  const { items, setField, selectedKey, readonly, placeholder } = props

  const renderOptions = (fields, level = 0) =>
    Object.keys(fields).map((fieldKey) => {
      const field = fields[fieldKey]
      const { items, path, label, disabled } = field
      const prefix = "\u00A0\u00A0".repeat(level)
      if (items) {
        return [
          <ListSubheader disabled={disabled} key={path} disableSticky={true}>
            {label}
          </ListSubheader>,
          renderOptions(items, level + 1)
        ]
      } else {
        return (
          <MenuItem disabled={disabled} key={path} value={path}>
            {prefix && <span>{prefix}</span>}
            {label}
          </MenuItem>
        )
      }
    })

  const onChange = (e) => {
    if (e.target.value === undefined) return
    setField(e.target.value)
  }

  const renderValue = (selectedValue) => {
    if (!readonly && !selectedValue) return placeholder
    const findLabel = (fields) => {
      return fields.map((field) => {
        if (!field.items)
          return field.path === selectedValue ? field.label : null
        return findLabel(field.items)
      })
    }
    return findLabel(items)
      .filter((v) => {
        if (Array.isArray(v)) {
          return v.some((value) => value !== null)
        } else {
          return v !== null
        }
      })
      .pop()
  }

  const hasValue = selectedKey != null
  return (
    <FormControl>
      <InputLabel id="select-field-label">
        {readonly ? placeholder : ""}
      </InputLabel>
      <Select
        autoWidth
        displayEmpty
        labelId="select-field-label"
        onChange={onChange}
        value={hasValue ? selectedKey : ""}
        disabled={readonly}
        renderValue={renderValue}
      >
        {renderOptions(items)}
      </Select>
    </FormControl>
  )
}