// Copyright 2018-2026 the Deno authors. MIT license.
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

(function () {
const { core, primordials } = __bootstrap;
const {
  SafeStringIterator,
  Symbol,
} = primordials;

const lazyTimers = core.createLazyLoader("node:timers");

const {
  charLengthAt,
  CSI,
  emitKeys,
} = core.loadExtScript("ext:deno_node/internal/readline/utils.mjs");
const { kSawKeyPress } = core.loadExtScript(
  "ext:deno_node/internal/readline/symbols.mjs",
);

const {
  kEscape,
} = CSI;

const { StringDecoder } = core.loadExtScript(
  "ext:deno_node/string_decoder.ts",
);

const KEYPRESS_DECODER = Symbol("keypress-decoder");
const ESCAPE_DECODER = Symbol("escape-decoder");

// GNU readline library - keyseq-timeout is 500ms (default)
const ESCAPE_CODE_TIMEOUT = 500;

/**
 * accepts a readable Stream instance and makes it emit "keypress" events
 */

function emitKeypressEvents(stream, iface = { __proto__: null }) {
  if (stream[KEYPRESS_DECODER]) return;

  stream[KEYPRESS_DECODER] = new StringDecoder("utf8");

  stream[ESCAPE_DECODER] = emitKeys(stream);
  // deno-lint-ignore deno-internal/prefer-primordials -- generator object, not an array
  stream[ESCAPE_DECODER].next();

  const triggerEscape = () =>
    // deno-lint-ignore deno-internal/prefer-primordials -- generator object, not an array
    stream[ESCAPE_DECODER].next("");
  const { escapeCodeTimeout = ESCAPE_CODE_TIMEOUT } = iface;
  let timeoutId;

  function onData(input) {
    if (stream.listenerCount("keypress") > 0) {
      const string = stream[KEYPRESS_DECODER].write(input);
      if (string) {
        lazyTimers().clearTimeout(timeoutId);

        // This supports characters of length 2.
        iface[kSawKeyPress] = charLengthAt(string, 0) === string.length;
        iface.isCompletionEnabled = false;

        let length = 0;
        for (const character of new SafeStringIterator(string)) {
          length += character.length;
          if (length === string.length) {
            iface.isCompletionEnabled = true;
          }

          try {
            // deno-lint-ignore deno-internal/prefer-primordials -- generator object, not an array
            stream[ESCAPE_DECODER].next(character);
            // Escape letter at the tail position
            if (length === string.length && character === kEscape) {
              timeoutId = lazyTimers().setTimeout(
                triggerEscape,
                escapeCodeTimeout,
              );
            }
          } catch (err) {
            // If the generator throws (it could happen in the `keypress`
            // event), we need to restart it.
            stream[ESCAPE_DECODER] = emitKeys(stream);
            // deno-lint-ignore deno-internal/prefer-primordials -- generator object, not an array
            stream[ESCAPE_DECODER].next();
            throw err;
          }
        }
      }
    } else {
      // Nobody's watching anyway
      stream.removeListener("data", onData);
      stream.on("newListener", onNewListener);
    }
  }

  function onNewListener(event) {
    if (event === "keypress") {
      stream.on("data", onData);
      stream.removeListener("newListener", onNewListener);
    }
  }

  if (stream.listenerCount("keypress") > 0) {
    stream.on("data", onData);
  } else {
    stream.on("newListener", onNewListener);
  }
}

return { emitKeypressEvents };
})();
