import { Node } from 'rdflib'

import { solidLogicSingleton } from 'solid-logic'

import { debug } from '../../log'

import { errorMessageBlock } from '../error'

const store = solidLogicSingleton.store

export type FieldFunction = (

dom: HTMLDocument, // the DOM

container: HTMLElement | undefined, // if defined, the box will be appended to it

already: { }, // used to avoid looping in nested forms

subject: Node, // the thing for which data will be loaded into the form element

form: Node, // the RDF declaration for what the form should have

doc: Node, // the online RDF document for data binding (form input values will be read/saved automatically)

callbackFunction: (ok: boolean, errorMessage: string) => void // this will be called when data changes (TODO: check this with unit tests)

) => HTMLElement

export const field: { [classUri: string]: FieldFunction } = {} // Form field functions by URI of field type.

/**

* Which class of field is this? Relies on http://www.w3.org/2000/01/rdf-schema#subClassOf and

* https://linkeddata.github.io/rdflib.js/doc/classes/formula.html#bottomtypeuris

* to find the most specific RDF type if there are multiple.

*

* @param x a form field, e.g. `namedNode('https://timbl.com/timbl/Public/Test/Forms/individualForm.ttl#fullNameField')`

* @returns the URI of the most specific known class, e.g. `http://www.w3.org/ns/ui#SingleLineTextField`

*/

export function mostSpecificClassURI (x: Node): string {

const kb = store

const ft = kb.findTypeURIs(x as any)

const bot = kb.bottomTypeURIs(ft) // most specific

const bots: any[] = []

for (const b in bot) bots.push(b)

// if (bots.length > 1) throw "Didn't expect "+x+" to have multiple bottom types: "+bots

return bots[0]

}

/**

* Returns a function that creates a form widget

* @param dom unused

* @param fieldInQuestion the field for which to create a form, e.g. namedNode('https://timbl.com/timbl/Public/Test/Forms/individualForm.ttl#fullNameField')

*/

export function fieldFunction (dom: any /* unused */, fieldInQuestion: Node): FieldFunction {

const uri = mostSpecificClassURI(fieldInQuestion) // What type

// const uri = field.uri

const fun = field[uri]

debug(

'paneUtils: Going to implement field ' + fieldInQuestion + ' of type ' + uri

)

if (!fun) {

return function (dom2: HTMLDocument, container?: HTMLElement): HTMLElement {

const box = errorMessageBlock(

dom2,

'No handler for field ' + fieldInQuestion + ' of type ' + uri

)

if (container) container.appendChild(box)

return box

}

}

return fun

}