// import { useState } from 'react'
import { useEffect, useState } from 'react';
import './App.css'
import { Editor, initialEditorState, type EditorState } from './Editor'
import { trie, apply, Int } from "dope2";

const listPush = trie.get(initialEditorState.env.name2dyn)("list.push");
const listEmptyList = trie.get(initialEditorState.env.name2dyn)("list.emptyList");
const fourtyTwo = {i: 42n, t: Int};

const nonEmptyEditorState: EditorState = {
  kind: "call",
  env: initialEditorState.env,
  fn: {
    kind: "call",
    env: initialEditorState.env,
    fn: {
      kind: "input",
      env: initialEditorState.env,
      text: "list.push",
      resolved: listPush,
    },
    input: {
      kind: "input",
      env: initialEditorState.env,
      text: "list.emptyList",
      resolved: listEmptyList,
    },
    resolved: apply(listEmptyList)(listPush),
  },
  input: {
    kind: "input",
    env: initialEditorState.env,
    text: "42",
    resolved: fourtyTwo,
  },
  resolved: apply(fourtyTwo)(apply(listEmptyList)(listPush)),
};

const functionWith3Params = trie.get(initialEditorState.env.name2dyn)("functionWith3Params");
const fourtyThree = {i: 43n, t: Int};
const fourtyFour = {i: 44n, t: Int};

const tripleFunctionCallEditorState: EditorState = {
  kind: "call",
  env: initialEditorState.env,
  fn: {
    kind: "call",
    env: initialEditorState.env,
    fn: {
      kind: "call",
      env: initialEditorState.env,
      fn: {
        kind: "input",
        env: initialEditorState.env,
        text: "functionWith3Params",
        resolved: functionWith3Params,
      },
      input: {
        kind: "input",
        env: initialEditorState.env,
        text: "42",
        resolved: fourtyTwo,
      },
      resolved: apply(fourtyTwo)(functionWith3Params),
    },
    input: {
      kind: "input",
      env: initialEditorState.env,
      text: "43",
      resolved: fourtyThree,
    },
    resolved: apply(fourtyThree)(apply(fourtyTwo)(functionWith3Params)),
  },
  input: {
    kind: "input",
    env: initialEditorState.env,
    text: "44",
    resolved: fourtyFour,
  },
  resolved: apply(fourtyFour)(apply(fourtyThree)(apply(fourtyTwo)(functionWith3Params))),
}

export function App() {
  const [history, setHistory] = useState([initialEditorState]);
  // const [history, setHistory] = useState([nonEmptyEditorState]);
  // const [history, setHistory] = useState([tripleFunctionCallEditorState]);

  const [future, setFuture] = useState<EditorState[]>([]);

  const pushHistory = (s: EditorState) => {
    console.log('pushHistory');
    setHistory(history.concat([s]));
    setFuture([]);
  };

  const onUndo = () => {
    setFuture(future.concat(history.at(-1)!)); // add
    setHistory(history.slice(0,-1)); // remove
  };
  const onRedo = () => {
    setHistory(history.concat(future.at(-1)!)); // add
    setFuture(future.slice(0,-1)); // remove
  };

  const onKeyDown = (e) => {
    if (e.key === "Z" && e.ctrlKey) {
      if (e.shiftKey) {
        if (future.length > 0) {
          onRedo();
        }
      }
      else {
        if (history.length > 1) {
          onUndo();
        }
      }
      e.preventDefault();
    }
  };


  useEffect(() => {
    window['APP_STATE'] = history;
    // console.log("EDITOR STATE:", state);
  }, [history]);

  useEffect(() => {
    window.onkeydown = onKeyDown;
  }, []);

  return (
    <>
      <header>
        <button disabled={history.length===1} onClick={onUndo}>Undo ({history.length-1}) [Ctrl+Z]</button>
        <button disabled={future.length===0} onClick={onRedo}>Redo ({future.length})  [Ctrl+Shift+Z]</button>
      </header>

      <main>
        <Editor
          state={history.at(-1)!}
          setState={pushHistory}
          onResolve={() => {console.log("toplevel resolved")}}
          onCancel={() => {console.log("toplevel canceled")}}
        />
      </main>

      <footer>
        <a href="https://deemz.org/git/joeri/dope2-webapp">Source code</a>
      </footer>
    </>
  )
}