import { setupLevelSelectUi } from './levelSelect.js';
import { render } from './render.js';


const X_START = '0';
const Y_START = 't';

const PATH_LEN = 20;
const PATH_STEP = PATH_LEN/1000;

const SLOW_RAMP = 1;
const FAST_RAMP = 0.01;


export function setupLevel(resources, home) {
  const level = {
    resources: resources.map(position => ({ position, collected: false })),
    home,
    running: false,
    completed: false,
    index: 0,
    equations: {
      xStr: X_START,
      x: math.compile(X_START),
      yStr: Y_START,
      y: math.compile(Y_START),
    },
  };
  level.path = computePath(level.equations);
  return level;
}


export function setupLevelUi(level, root, sfx) {
  const ui = { root, sfx };

  root.classList.add('center');
  ui.launchButton = document.createElement('input');
  ui.launchButton.type = 'button';
  ui.launchButton.value = 'launch';
  ui.launchButton.onmouseenter = () => {
    sfx.buttonEnterAudio.currentTime = 0;
    sfx.buttonEnterAudio.play();
  }
  ui.launchButton.onclick = () => {
    sfx.buttonClickAudio.currentTime = 0;
    sfx.buttonClickAudio.play();
    ui.message.innerText = '';
    level.running = false;
    setTimeout(() => { level.running=true; stepLevel(ui, level, 0); }, 20);
  }

  ui.xeq = document.createElement('input');
  ui.xeq.id = 'xeq';
  ui.xeq.value = level.equations.xStr;
  ui.xeq.onchange = (e) => {
    try {
      level.equations.xStr = e.target.value;
      level.equations.x = math.compile(e.target.value);
    } catch(err) { }
    level.running = false;
    level.path = computePath(level.equations);
    level.resources.forEach(x => x.collected = false);
    render(ui.ctx, level, 0);
  };
  ui.xeq.onkeydown = ui.xeq.onchange;
  ui.xeq.onkeyup = ui.xeq.onchange;
  ui.xeqLabel = document.createElement('label');
  ui.xeqLabel.htmlFor = 'xeq';
  ui.xeqLabel.innerText = 'x(t) = ';

  ui.yeq = document.createElement('input');
  ui.yeq.value = level.equations.yStr;
  ui.yeq.onchange = (e) => {
    try {
      level.equations.yStr = e.target.value;
      level.equations.y = math.compile(e.target.value);
    } catch(err) { }
    level.running = false;
    level.path = computePath(level.equations);
    level.resources.forEach(x => x.collected = false);
    render(ui.ctx, level, 0);
  };
  ui.yeq.onkeydown = ui.yeq.onchange;
  ui.yeq.onkeyup = ui.yeq.onchange;
  ui.yeqLabel = document.createElement('label');
  ui.yeqLabel.htmlFor = 'yeq';
  ui.yeqLabel.innerText = 'y(t) = ';

  ui.message = document.createElement('div');
  ui.id = "level-message";

  const appearSound = () => { sfx.listAppearAudio.currentTime = 0; sfx.listAppearAudio.play(); };
  setTimeout(() => {
    root.appendChild(ui.xeqLabel);
    root.appendChild(ui.xeq);
    root.appendChild(document.createElement('br'));
    appearSound();
  }, 100);
  setTimeout(() => {
    root.appendChild(ui.yeqLabel);
    root.appendChild(ui.yeq);
    root.appendChild(document.createElement('br'));
    appearSound();
  }, 200);
  setTimeout(() => {
    root.appendChild(ui.launchButton);
    root.appendChild(ui.message);
    appearSound();
  }, 300);

  ui.canvas = document.createElement('canvas');
  ui.canvas.classList.add('bordered');
  const setCanvasSize = () => {
    const size = Math.min(0.8*window.innerHeight, 0.9*root.offsetWidth);
    ui.canvas.width = size;
    ui.canvas.height = size;
    ui.ctx = ui.canvas.getContext('2d');
    ui.ctx.translate(ui.canvas.width/2, ui.canvas.height/2)
    ui.ctx.scale(ui.canvas.width/20, -ui.canvas.height/20);
    render(ui.ctx, level, 0);
  }
  setCanvasSize();
  window.onresize = setCanvasSize;
  setTimeout(() => {
    root.appendChild(ui.canvas);
    root.appendChild(document.createElement('br'));
    appearSound();
  }, 400);


  ui.returnBtn = document.createElement('input');
  ui.returnBtn.type = 'button';
  ui.returnBtn.value = '↲ return';
  ui.returnBtn.onmouseenter = () => {
    sfx.buttonEnterAudio.currentTime = 0;
    sfx.buttonEnterAudio.play();
  }
  ui.returnBtn.onclick = () => {
    sfx.buttonClickAudio.currentTime = 0;
    sfx.buttonClickAudio.play();
    root.innerText = '';
    root.classList.remove('center');
    window.onresize = () => {};
    setupLevelSelectUi(root, sfx);
  }
  setTimeout(() => {
    root.appendChild(ui.returnBtn);
    appearSound();
  }, 500);

  return ui;
}


function stepLevel(ui, level, index) {
  render(ui.ctx, level, index);

  const pos = level.path[index];
  const distances = level.resources
    .map((x, i) => [x, i])
    .filter(([x, _]) => x.collected === false)
    .map(([x, i]) => [ distance(pos, x.position), i ])
    .forEach(([d, i]) => {
      if (d < 0.4) { 
        ui.sfx.resourceAudio.currentTime = 0;
        ui.sfx.resourceAudio.play();
        level.resources[i].collected = true; 
      }
    });



  if (distance(pos, level.home) < 0.4) {
    level.running = false;
    finishLevel(ui, level, false);
    render(ui.ctx, level, 0);
  } else if (level.running && index < level.path.length-1) {
    const distNext = distance(pos, level.path[index+1] || pos);
    setTimeout(() => stepLevel(ui, level, index+1), 50*distNext);
  } else {
    if (index >= level.path.length-1) {
      finishLevel(ui, level, true);
    }
    level.running = false;
    render(ui.ctx, level, 0);
  }
}


function computePath(equations, start, end, step) {
  try {
    const ts = [...Array(Math.floor((PATH_LEN)/PATH_STEP)).keys()].map(k => PATH_STEP * k);
    return ts.map(t => [ equations.x.eval({t}), equations.y.eval({t}) ]);
  } catch (err) {
    return [ [0, 0] ];
  }
}


function distance(p1, p2) {
  const [x1, y1] = p1;
  const [x2, y2] = p2;
  return Math.sqrt((x2-x1)**2 + (y2-y1)**2);
}


function finishLevel(ui, level, fail) {
  const uncollected = level.resources.reduce((acc, { collected }) => acc + (collected ? 0 : 1), 0);
  if (fail) {
    ui.sfx.wrongAudio.currentTime = 0;
    ui.sfx.wrongAudio.play();
    showAlert(ui, 'trajectory does not reach AMH processor');
    // ui.message.innerText = 'did not arrive at destination';
  } else if (uncollected > 0) {
    ui.sfx.wrongAudio.currentTime = 0;
    ui.sfx.wrongAudio.play();
    showAlert(ui, 'monopole harvesting failure');
    // ui.message.innerText = 'resources remaining!';
  } else {
    ui.sfx.doneAudio.currentTime = 0;
    ui.sfx.doneAudio.play();
    showAlert(ui, 'navigation successful: contract complete', true);
    // ui.message.innerText = 'mission complete!';
    level.completed = true;
  }
  level.resources.forEach(x => x.collected = false);
}


function showAlert(ui, text, ret) {
  const div = document.createElement('div');
  div.classList.add('center-screen-container');
  const div2 = document.createElement('div');
  div2.classList.add('center-screen');
  div.appendChild(div2);
  const p = document.createElement('p');
  p.classList.add('alert-box');
  p.innerText = text;
  div2.appendChild(p);
  ui.root.appendChild(div);

  const button = document.createElement('input');
  button.type = 'button';
  button.value = 'OK';
  button.onmouseenter = () => {
    ui.sfx.buttonEnterAudio.currentTime = 0;
    ui.sfx.buttonEnterAudio.play();
  }
  button.onclick = () => {
    ui.sfx.buttonClickAudio.currentTime = 0;
    ui.sfx.buttonClickAudio.play();
    ui.root.removeChild(div);
  }
  p.appendChild(document.createElement('br'));
  p.appendChild(button);

  if (ret) {
    const returnBtn = document.createElement('input');
    returnBtn.type = 'button';
    returnBtn.value = '↲ return';
    returnBtn.onmouseenter = () => {
      ui.sfx.buttonEnterAudio.currentTime = 0;
      ui.sfx.buttonEnterAudio.play();
    }
    returnBtn.onclick = () => {
      ui.sfx.buttonClickAudio.currentTime = 0;
      ui.sfx.buttonClickAudio.play();
      ui.root.innerText = '';
      ui.root.classList.remove('center');
      window.onresize = () => {};
      setupLevelSelectUi(ui.root, ui.sfx);
    }
    p.appendChild(returnBtn);
  }
}