import type { FoundSyntax, ParseError } from '../../../languages/lisp';
import { spanLabel } from '../../format';

export function errorTitle(error: ParseError): string {
  switch (error.tag) {
    case "expected-expression":
      return "Expected expression";
    case "expected-close-delimiter":
      return "Expected closing delimiter";
    case "unexpected-close-delimiter":
      return "Unexpected closing delimiter";
    case "expected-list-separator":
      return "Expected list separator";
    case "unexpected-code-point":
      return "Unexpected code point";
    case "invalid-number":
      return "Invalid number";
  }
}

export function errorDetail(error: ParseError): string {
  switch (error.tag) {
    case "expected-expression":
      return `found ${foundLabel(error.found)}`;
    case "expected-close-delimiter":
      return `expected ${error.expected}, opened at ${spanLabel(error.open)}, found ${foundLabel(error.found)}`;
    case "unexpected-close-delimiter":
      return `${error.delimiter} ${spanLabel(error.span)}`;
    case "expected-list-separator":
      return `found ${foundLabel(error.found)}`;
    case "unexpected-code-point":
      return `found ${foundLabel(error.found)}`;
    case "invalid-number":
      return `${error.reason}: ${error.text}`;
  }
}

function foundLabel(found: FoundSyntax): string {
  switch (found.tag) {
    case "eof":
      return `EOF ${spanLabel(found.span)}`;
    case "code-point":
      return `${String.fromCodePoint(found.value)} ${spanLabel(found.span)}`;
  }
}