import { exec } from "child_process";
import { IncomingMessage, request } from "http";
import { window } from "vscode";
import { findReferences, Reference } from "./reference";

// when called as command using keyboard, reference argument is undefined
// in that case, try to find one under the current cursor.
function resolveReferenceArgument(reference: Reference | undefined): Reference|undefined {
  if (reference === undefined) {
    const editor = window.activeTextEditor;
    if (!editor) {
      console.log("No active editor to run command");
      return;
    }
    const position = editor.selection.active;
    const referencesAtCursor = findReferences(editor.document).filter(ref => ref.range.contains(position));
    if (referencesAtCursor.length < 1) {
      window.showWarningMessage("No reference at cursor position.");
      return;
    }
    return referencesAtCursor[0];
  }
  return reference;
}

async function showInZotero(reference?: Reference) {
  const ref = resolveReferenceArgument(reference);
  if (!ref) { return; }
  openUrl("zotero://select/items/@" + ref.citekey);
}

async function openZoteroPDF(reference?: Reference) {
  const ref = resolveReferenceArgument(reference);
  if (!ref) {
    return;
  }

  const req = request("http://127.0.0.1:23119/better-bibtex/json-rpc", {
    'method': 'POST',
    'headers': {
      'Content-Type': 'application/json',
      'Accept': 'application/json'
    }
  });
  req.on("response", (res: IncomingMessage) => {
    if (res.statusCode !== 200) {
      console.error('Error with request. Is Zotero running and Better-BibTex installed?')
    } else {
      // console.log('test2', res.statusCode, res);
      res.on('readable', () => {
        const buffer: Buffer = res.read();
        const s = buffer.toString();
        const data = JSON.parse(s);

        console.log('received from Zotero', data);
        for (const result of data['result']) {
          if (result['path'].toLowerCase().endsWith('.pdf')) {
            // TODO add ?page=nr to open given page

            const pagenr = ref.pagenr !== null ? "?page=" + ref.pagenr : "";
            openUrl(result['open'] + pagenr);
            break; // only open a single attachement
          }
        }
      });
    }
  });

  req.end('{"jsonrpc": "2.0", "method": "item.attachments", "params": ["' + ref.citekey + '"]}', 'binary');
}

function openUrl(url: string) {
  // console.log('open', url);
  switch (process.platform) {
    case 'darwin':
      exec('open "' + url + '"');
      break;
    case 'linux':
      exec('xdg-open "' + url + '"');
      break;
    default:
      exec('"' + url + '"');
  }

}

export { openZoteroPDF, showInZotero };