module ProfileFormFields = %lenses(
  type t = {
    nickname: string,
    age: int,
  }
)

module FormFields = %lenses(
  type state = {
    name: string,
    email: string,
    profiles: array<ProfileFormFields.t>,
  }
)

module Form = ReForm.Make(FormFields)

module ReFormPresenter = {
  @react.component
  let make = () => {
    let handleSubmit = ({state}: Form.onSubmitAPI) => {
      Js.log2("submit >", state.values)

      None
    }

    let form = Form.use(
      ~initialState={name: "", email: "", profiles: [{nickname: "", age: 0}]},
      ~onSubmit=handleSubmit,
      ~validationStrategy=OnDemand,
      ~schema={
        open Form.Validation

        schema([string(~min=3, Name), custom(({profiles}) => {
            let errors: array<ReSchema.childFieldError> =
              profiles
              ->Array.mapWithIndex((index, profile) =>
                if profile.nickname == "" || profile.age <= 0 {
                  let error: ReSchema.childFieldError = {
                    error: "Invalid profile",
                    index,
                    name: "???",
                  }
                  Some(error)
                } else {
                  None
                }
              )
              ->Array.keepMap(x => x)

            switch errors {
            | [] => Valid
            | _ => NestedErrors(errors)
            }
          }, Profiles), email(~error="Invalid email", Email)])
      },
      (),
    )

    <div>
      <div>
        <div> {"Sign up"->React.string} </div>
        <div>
          <input
            placeholder="Your name"
            value={form.values.name}
            onChange={ReForm.Helpers.handleChange(form.handleChange(Name))}
          />
          {switch Field(Name)->form.getFieldError {
          | None => React.null
          | Some(message) => <div> {message->React.string} </div>
          }}
        </div>
        <div>
          <input
            placeholder="Your email"
            value={form.values.email}
            onChange={ReForm.Helpers.handleChange(form.handleChange(Email))}
          />
          {switch Field(Email)->form.getFieldError {
          | None => React.null
          | Some(message) => <div> {message->React.string} </div>
          }}
        </div>
        <button onClick={_ => form.arrayPush(Profiles, {nickname: "", age: 0})}>
          {React.string("Add profile")}
        </button>
        {form.values.profiles
        ->Array.mapWithIndex((index, profile) =>
          <div key={index->Int.toString} className=%twc("flex flex-row")>
            <input
              placeholder={"Your nickname"}
              value={profile.nickname}
              onChange={ReForm.Helpers.handleChange(nickname =>
                form.arrayUpdateByIndex(~field=Profiles, ~index, {...profile, nickname})
              )}
            />
            {switch Field(Profiles)->form.getNestedFieldError(index) {
            | None => React.null
            | Some(message) => <div> {message->React.string} </div>
            }}
            <input
              placeholder={`Your age`}
              value={profile.age->Int.toString}
              onChange={ReForm.Helpers.handleChange(age => {
                let age = Int.fromString(age)->Belt.Option.getWithDefault(0)
                form.arrayUpdateByIndex(~field=Profiles, ~index, {...profile, age})
              })}
            />
            {switch Field(Profiles)->form.getNestedFieldError(index) {
            | None => React.null
            | Some(message) => <div> {message->React.string} </div>
            }}
            <button onClick={_ => form.arrayRemoveByIndex(Profiles, index)}>
              {React.string("Remove")}
            </button>
          </div>
        )
        ->React.array}
        <div>
          <button
            onClick={e => {
              e->ReactEvent.Mouse.preventDefault
              form.submit()
            }}>
            {"Submit"->React.string}
          </button>
        </div>
      </div>
    </div>
  }
}