// Web apps which integrate Surfer as an iframe can give commands to surfer via
// the .postMessage [1] function on the iframe.
//
//  For example, to tell Surfer to load waveforms from a URL, use
// `.postMessage({command: "LoadUrl", url: "https://app.surfer-project.org/picorv32.vcd"})`
//
//  For more complex functionality, one can also inject any `Message` defined
// in `surfer::Message` in surfer/main.rs. However, the API of these messages
// is not stable and may change at any time. If you add functionality via
// these, make sure to test the new functionality when changing Surfer version.
//
// [1] https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage

function register_message_listener() {
  window.addEventListener("message", (event) => {
    // JSON decode the message
    const decoded = event.data

    switch (decoded.command) {
      // Load a waveform from a URL. The format is inferred from the data.
      // Example: `{command: "LoadUrl", url: "https://app.surfer-project.org/picorv32.vcd"}`

      case 'LoadUrl': {
        const msg = {
          LoadWaveformFileFromUrl: [
            decoded.url,
            "Clear"
          ]
        }
        inject_message(JSON.stringify(msg))
        break;
      }

      case 'ToggleMenu': {
        const msg = "ToggleMenu"
        inject_message(JSON.stringify(msg))
        break;
      }

      // Load waveform data directly from string content
      case 'LoadData': {
        const msg = {
          LoadFromData: [
            decoded.content,
            decoded.fileName || "waveform.vcd",
            "Clear"
          ]
        }
        inject_message(JSON.stringify(msg))
        break;
      }

      // Inject any other message supported by Surfer in the surfer::Message enum.
      // NOTE: The API of these is unstable.
      case 'InjectMessage': {
        inject_message(decoded.message);
        break
      }

      default:
        console.log(`Unknown message.command ${decoded.command}`)
        break;
    }
  });
}