import assert = require("assert")
import Convert from "../convert"
import { Point, TextEditor, Range } from "atom"
import { LanguageClientConnection, ServerCapabilities } from "../languageclient"

export default class CodeHighlightAdapter {
  /** @returns A {Boolean} indicating this adapter can adapt the server based on the given serverCapabilities. */
  public static canAdapt(serverCapabilities: ServerCapabilities): boolean {
    return serverCapabilities.documentHighlightProvider === true
  }

  /**
   * Public: Creates highlight markers for a given editor position. Throws an error if documentHighlightProvider is not
   * a registered capability.
   *
   * @param connection A {LanguageClientConnection} to the language server that provides highlights.
   * @param serverCapabilities The {ServerCapabilities} of the language server that will be used.
   * @param editor The Atom {TextEditor} containing the text to be highlighted.
   * @param position The Atom {Point} to fetch highlights for.
   * @returns A {Promise} of an {Array} of {Range}s to be turned into highlights.
   */
  public static async highlight(
    connection: LanguageClientConnection,
    serverCapabilities: ServerCapabilities,
    editor: TextEditor,
    position: Point
  ): Promise<Range[]> {
    assert(serverCapabilities.documentHighlightProvider, "Must have the documentHighlight capability")
    const highlights = await connection.documentHighlight(Convert.editorToTextDocumentPositionParams(editor, position))
    if (highlights === null) {
      return []
    }
    return highlights.map((highlight) => {
      return Convert.lsRangeToAtomRange(highlight.range)
    })
  }
}