import type { SourceRange } from "./frontend/ast/node";
import { getFile } from "./io/files";

const errors: [SourceRange, string][] = []

export function raiseError(sourceRange: SourceRange, message: string) {
  errors.push([sourceRange, message]);
}

export function hasErrors() {
  return errors.length > 0;
}

export function getErrors() {
  return [...errors];
}

function getPreviousLines(content: string, line: number, count: number = 6) {
  let lines = content.split("\n");
  lines = lines.slice(Math.max(0, line - count), line);
  while (!lines[0].trim().length) lines.shift();
  while (!lines[lines.length - 1].trim().length) lines.pop();
  return lines.join('\n');
}

export function printErrors() {
  for (let i = 0; i < errors.length; i++) {
    const [sourceRange, message] = errors[i];

    const { path, content } = getFile(sourceRange.file);
    const ctx = getPreviousLines(content, sourceRange.start[0]);
    process.stderr.write(`in ${path}:${sourceRange.start[0]}:${sourceRange.start[1] + 1}\n`);
    process.stderr.write('\x1b[90m' + ctx + '\x1b[0m\n');
    process.stderr.write('\x1b[91m' + message + '\x1b[0m\n');

    if (i < errors.length - 1) process.stderr.write('\n');
  }
}