import {EventTarget, CustomEvent} from '../../common/event-target';

let console = window.console;

/*
Mapping types:

type: "key" maps a button to a keyboard key
All key names will be interpreted as a KeyboardEvent.key value (https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/key/Key_Values)
high: "KeyName" is the name of the key to dispatch when a button reads a HIGH value
low: "KeyName" is the name of the key to dispatch when a button reads a LOW value
deadZone: 0.5 controls the minimum value necessary to be read in either + or - to trigger either high or low
The high/low distinction is necessary for axes. Buttons will only use high

type: "mousedown" maps a button to control whether the mouse is down or not
deadZone: 0.5 controls the minimum value to trigger a mousedown
button: 0, 1, 2, etc. controls which button to press

type: "virtual_cursor" maps a button to control the "virtual cursor"
deadZone: 0.5 again controls the minimum value to trigger a movement
sensitivity: 10 controls the speed
high: "+y"/"-y"/"+x"/"-x" defines what happens when an axis reads high
low: "+y"/"-y"/"+x"/"-x" defines what happens when an axis reads low
+y increases y, -y decreases y, +x increases x, -x decreases x.
*/

const defaultAxesMappings = {
  arrows: [
    {
      type: "key",
      high: "ArrowRight",
      low: "ArrowLeft",
      deadZone: 0.5,
    },
    {
      type: "key",
      high: "ArrowDown",
      low: "ArrowUp",
      deadZone: 0.5,
    },
  ],
  wasd: [
    {
      type: "key",
      high: "d",
      low: "a",
      deadZone: 0.5,
    },
    {
      type: "key",
      high: "s",
      low: "w",
      deadZone: 0.5,
    },
  ],
  cursor: [
    {
      type: "virtual_cursor",
      high: "+x",
      low: "-x",
      sensitivity: 0.6,
      deadZone: 0.2,
    },
    {
      type: "virtual_cursor",
      high: "-y",
      low: "+y",
      sensitivity: 0.6,
      deadZone: 0.2,
    },
  ],
};

const emptyMapping = () => ({
  type: "key",
  high: null,
  low: null,
});
const transformAndCopyMapping = (mapping) => {
  if (typeof mapping !== "object" || !mapping) {
    console.warn("invalid mapping", mapping);
    return emptyMapping();
  }
  const copy = Object.assign({}, mapping);
  if (copy.type === "key") {
    if (typeof copy.deadZone === "undefined") {
      copy.deadZone = 0.5;
    }
    if (typeof copy.high === "undefined") {
      copy.high = "";
    }
    if (typeof copy.low === "undefined") {
      copy.low = "";
    }
  } else if (copy.type === "mousedown") {
    if (typeof copy.deadZone === "undefined") {
      copy.deadZone = 0.5;
    }
    if (typeof copy.button === "undefined") {
      copy.button = 0;
    }
  } else if (copy.type === "virtual_cursor") {
    if (typeof copy.high === "undefined") {
      copy.high = "";
    }
    if (typeof copy.low === "undefined") {
      copy.low = "";
    }
    if (typeof copy.sensitivity === "undefined") {
      copy.sensitivity = 10;
    }
    if (typeof copy.deadZone === "undefined") {
      copy.deadZone = 0.5;
    }
  } else {
    console.warn("unknown mapping type", copy.type);
    return emptyMapping();
  }
  return copy;
};
const prepareMappingForExport = (mapping) => Object.assign({}, mapping);
const prepareAxisMappingForExport = prepareMappingForExport;
const prepareButtonMappingForExport = (mapping) => {
  const copy = prepareMappingForExport(mapping);
  delete copy.deadZone;
  delete copy.low;
  return copy;
};

const padWithEmptyMappings = (array, length) => {
  // Keep adding empty mappings until the list is full
  while (array.length < length) {
    array.push(emptyMapping());
  }
  // In case the input array is longer than the desired length
  array.length = length;
  return array;
};

const createEmptyMappingList = (length) => padWithEmptyMappings([], length);

const getMovementConfiguration = (usedKeys) => ({
  usesArrows:
    usedKeys.has("ArrowUp") || usedKeys.has("ArrowDown") || usedKeys.has("ArrowRight") || usedKeys.has("ArrowLeft"),
  usesWASD: (usedKeys.has("w") && usedKeys.has("s")) || (usedKeys.has("a") && usedKeys.has("d")),
});

const getGamepadId = (gamepad) => `${gamepad.id} (${gamepad.index})`;

class GamepadData {
  /**
   * @param {Gamepad} gamepad Source Gamepad
   * @param {GamepadLib} gamepadLib Parent GamepadLib
   */
  constructor(gamepad, gamepadLib) {
    this.gamepad = gamepad;
    this.gamepadLib = gamepadLib;
    this.resetMappings();
  }

  resetMappings() {
    this.hints = this.gamepadLib.getHints();
    this.buttonMappings = this.getDefaultButtonMappings().map(transformAndCopyMapping);
    this.axesMappings = this.getDefaultAxisMappings().map(transformAndCopyMapping);
  }

  clearMappings() {
    this.buttonMappings = createEmptyMappingList(this.gamepad.buttons.length);
    this.axesMappings = createEmptyMappingList(this.gamepad.axes.length);
  }

  getDefaultButtonMappings() {
    let buttons;
    if (this.hints.importedSettings) {
      buttons = this.hints.importedSettings.buttons;
    } else {
      const usedKeys = this.hints.usedKeys;
      const alreadyUsedKeys = new Set();
      const { usesArrows, usesWASD } = getMovementConfiguration(usedKeys);
      if (usesWASD) {
        alreadyUsedKeys.add("w");
        alreadyUsedKeys.add("a");
        alreadyUsedKeys.add("s");
        alreadyUsedKeys.add("d");
      }
      const possiblePauseKeys = [
        // Restart keys, pause keys, other potentially dangerous keys
        "p",
        "q",
        "r",
      ];
      const possibleActionKeys = [
        " ",
        "Enter",
        "e",
        "f",
        "z",
        "x",
        "c",
        ...Array.from(usedKeys).filter((i) => i.length === 1 && !possiblePauseKeys.includes(i)),
      ];

      const findKey = (keys) => {
        for (const key of keys) {
          if (usedKeys.has(key) && !alreadyUsedKeys.has(key)) {
            alreadyUsedKeys.add(key);
            return key;
          }
        }
        return null;
      };
      const getPrimaryAction = () => {
        if (usesArrows && usedKeys.has("ArrowUp")) {
          return "ArrowUp";
        }
        if (usesWASD && usedKeys.has("w")) {
          return "w";
        }
        return findKey(possibleActionKeys);
      };
      const getSecondaryAction = () => findKey(possibleActionKeys);
      const getPauseKey = () => findKey(possiblePauseKeys);
      const getUp = () => {
        if (usesArrows || !usesWASD) return "ArrowUp";
        return "w";
      };
      const getDown = () => {
        if (usesArrows || !usesWASD) return "ArrowDown";
        return "s";
      };
      const getRight = () => {
        if (usesArrows || !usesWASD) return "ArrowRight";
        return "d";
      };
      const getLeft = () => {
        if (usesArrows || !usesWASD) return "ArrowLeft";
        return "a";
      };

      const action1 = getPrimaryAction();
      let action2 = getSecondaryAction();
      let action3 = getSecondaryAction();
      let action4 = getSecondaryAction();
      // When only 1 or 2 action keys are detected, bind the other buttons to the same things.
      if (action1 && !action2 && !action3 && !action4) {
        action2 = action1;
        action3 = action1;
        action4 = action1;
      }
      if (action1 && action2 && !action3 && !action4) {
        action3 = action1;
        action4 = action2;
      }

      // Set indices "manually" because we don't evaluate them in order.
      buttons = [];
      buttons[0] = {
        /*
        Xbox: A
        SNES-like: B
        */
        type: "key",
        high: action1,
      };
      buttons[1] = {
        /*
        Xbox: B
        SNES-like: A
        */
        type: "key",
        high: action2,
      };
      buttons[2] = {
        /*
        Xbox: X
        SNES-like: Y
        */
        type: "key",
        high: action3,
      };
      buttons[3] = {
        /*
        Xbox: Y
        SNES-like: X
        */
        type: "key",
        high: action4,
      };
      buttons[4] = {
        /*
        Xbox: LB
        SNES-like: Left trigger
        */
        type: "mousedown",
      };
      buttons[5] = {
        /*
        Xbox: RB
        */
        type: "mousedown",
      };
      buttons[6] = {
        /*
        Xbox: LT
        */
        type: "mousedown",
      };
      buttons[7] = {
        /*
        Xbox: RT
        SNES-like: Right trigger
        */
        type: "mousedown",
      };
      buttons[9] = {
        /*
        Xbox: Menu
        SNES-like: Start
        */
        type: "key",
        high: getPauseKey(),
      };
      buttons[8] = {
        /*
        Xbox: Change view
        SNES-like: Select
        */
        type: "key",
        high: getPauseKey(),
      };
      // Xbox: Left analog press
      buttons[10] = emptyMapping();
      // Xbox: Right analog press
      buttons[11] = emptyMapping();
      buttons[12] = {
        /*
        Xbox: D-pad up
        */
        type: "key",
        high: getUp(),
      };
      buttons[13] = {
        /*
        Xbox: D-pad down
        */
        type: "key",
        high: getDown(),
      };
      buttons[14] = {
        /*
        Xbox: D-pad left
        */
        type: "key",
        high: getLeft(),
      };
      buttons[15] = {
        /*
        Xbox: D-pad right
        */
        type: "key",
        high: getRight(),
      };
    }
    return padWithEmptyMappings(buttons, this.gamepad.buttons.length);
  }

  getDefaultAxisMappings() {
    let axes = [];
    if (this.hints.importedSettings) {
      axes = this.hints.importedSettings.axes;
    } else {
      // Only return default axis mappings when there are 4 axes, like an xbox controller
      // If there isn't exactly 4, we can't really predict what the axes mean
      // Some controllers map the dpad to *both* buttons and axes at the same time, which would cause conflicts.
      if (this.gamepad.axes.length === 4) {
        const usedKeys = this.hints.usedKeys;
        const { usesArrows, usesWASD } = getMovementConfiguration(usedKeys);
        if (usesWASD) {
          axes.push(defaultAxesMappings.wasd[0]);
          axes.push(defaultAxesMappings.wasd[1]);
        } else if (usesArrows) {
          axes.push(defaultAxesMappings.arrows[0]);
          axes.push(defaultAxesMappings.arrows[1]);
        } else {
          axes.push(defaultAxesMappings.cursor[0]);
          axes.push(defaultAxesMappings.cursor[1]);
        }
        axes.push(defaultAxesMappings.cursor[0]);
        axes.push(defaultAxesMappings.cursor[1]);
      }
    }
    return padWithEmptyMappings(axes, this.gamepad.axes.length);
  }
}

const defaultHints = () => ({
  usedKeys: new Set(),
  importedSettings: null,
  generated: false,
});

class GamepadLib extends EventTarget {
  constructor() {
    super();

    /** @type {Map<string, GamepadData>} */
    this.gamepads = new Map();

    this.handleConnect = this.handleConnect.bind(this);
    this.handleDisconnect = this.handleDisconnect.bind(this);
    this.update = this.update.bind(this);

    this.animationFrame = null;
    this.currentTime = null;
    this.deltaTime = 0;

    this.virtualCursor = {
      x: 0,
      y: 0,
      maxX: Infinity,
      minX: -Infinity,
      maxY: Infinity,
      minY: -Infinity,
      modified: false,
    };

    this._editor = null;

    this.connectCallbacks = [];

    this.keysPressedThisFrame = new Set();
    this.oldKeysPressed = new Set();

    this.mouseButtonsPressedThisFrame = new Set();
    this.oldMouseDown = new Set();

    this.addEventHandlers();
  }

  addEventHandlers() {
    window.addEventListener("gamepadconnected", this.handleConnect);
    window.addEventListener("gamepaddisconnected", this.handleDisconnect);
  }

  removeEventHandlers() {
    window.removeEventListener("gamepadconnected", this.handleConnect);
    window.removeEventListener("gamepaddisconnected", this.handleDisconnect);
  }

  gamepadConnected() {
    if (this.gamepads.size > 0) {
      return Promise.resolve();
    }
    return new Promise((resolve) => {
      this.connectCallbacks.push(resolve);
    });
  }

  getHints() {
    return Object.assign(defaultHints(), this.getUserHints());
  }

  getUserHints() {
    // to be overridden by users
    return {};
  }

  resetControls() {
    for (const gamepad of this.gamepads.values()) {
      gamepad.resetMappings();
    }
  }

  clearControls() {
    for (const gamepad of this.gamepads.values()) {
      gamepad.clearMappings();
    }
  }

  handleConnect(e) {
    for (const callback of this.connectCallbacks) {
      callback();
    }
    this.connectCallbacks = [];
    const gamepad = e.gamepad;
    const id = getGamepadId(gamepad);
    console.log("connected", gamepad);
    const gamepadData = new GamepadData(gamepad, this);
    this.gamepads.set(id, gamepadData);
    if (this.animationFrame === null) {
      this.animationFrame = requestAnimationFrame(this.update);
    }
    this.dispatchEvent(new CustomEvent("gamepadconnected", { detail: gamepadData }));
  }

  handleDisconnect(e) {
    const gamepad = e.gamepad;
    const id = getGamepadId(gamepad);
    console.log("disconnected", gamepad);
    const gamepadData = this.gamepads.get(id);
    this.gamepads.delete(id);
    this.dispatchEvent(new CustomEvent("gamepaddisconnected", { detail: gamepadData }));
    if (this.gamepads.size === 0) {
      cancelAnimationFrame(this.animationFrame);
      this.animationFrame = null;
      this.currentTime = null;
    }
  }

  dispatchKey(key, pressed) {
    if (pressed) {
      this.dispatchEvent(new CustomEvent("keydown", { detail: key }));
    } else {
      this.dispatchEvent(new CustomEvent("keyup", { detail: key }));
    }
  }

  dispatchMouse(button, down) {
    if (down) {
      this.dispatchEvent(new CustomEvent("mousedown", { detail: button }));
    } else {
      this.dispatchEvent(new CustomEvent("mouseup", { detail: button }));
    }
  }

  dispatchMouseMove(x, y) {
    this.dispatchEvent(new CustomEvent("mousemove", { detail: { x, y } }));
  }

  updateButton(value, mapping) {
    if (mapping.type === "key") {
      if (value >= mapping.deadZone) {
        if (mapping.high) {
          this.keysPressedThisFrame.add(mapping.high);
        }
      } else if (value <= -mapping.deadZone) {
        if (mapping.low) {
          this.keysPressedThisFrame.add(mapping.low);
        }
      }
    } else if (mapping.type === "mousedown") {
      const isDown = Math.abs(value) >= mapping.deadZone;
      if (isDown) {
        this.mouseButtonsPressedThisFrame.add(mapping.button);
      }
    } else if (mapping.type === "virtual_cursor") {
      const deadZone = mapping.deadZone;
      let action;
      if (value >= deadZone) action = mapping.high;
      if (value <= -deadZone) action = mapping.low;
      if (action) {
        // an axis value just beyond the deadzone should have a multiplier near 0, a high value should have a multiplier of 1
        const multiplier = (Math.abs(value) - deadZone) / (1 - deadZone);
        const speed = multiplier * multiplier * mapping.sensitivity * this.deltaTime;
        if (action === "+x") {
          this.virtualCursor.x += speed;
        } else if (action === "-x") {
          this.virtualCursor.x -= speed;
        } else if (action === "+y") {
          this.virtualCursor.y += speed;
        } else if (action === "-y") {
          this.virtualCursor.y -= speed;
        }
        this.virtualCursor.modified = true;
      }
    }
  }

  update(time) {
    this.oldKeysPressed = this.keysPressedThisFrame;
    this.oldMouseButtonsPressed = this.mouseButtonsPressedThisFrame;
    this.keysPressedThisFrame = new Set();
    this.mouseButtonsPressedThisFrame = new Set();

    if (this.currentTime === null) {
      this.deltaTime = 0; // doesn't matter what this is, it's just the first frame
    } else {
      this.deltaTime = time - this.currentTime;
    }
    this.deltaTime = Math.max(Math.min(this.deltaTime, 1000), 0);
    this.currentTime = time;

    this.animationFrame = requestAnimationFrame(this.update);

    const gamepads = navigator.getGamepads();
    for (const gamepad of gamepads) {
      if (gamepad === null) {
        continue;
      }

      const id = getGamepadId(gamepad);
      const data = this.gamepads.get(id);

      for (let i = 0; i < gamepad.buttons.length; i++) {
        const button = gamepad.buttons[i];
        const value = button.value;
        const mapping = data.buttonMappings[i];
        this.updateButton(value, mapping);
      }

      for (let i = 0; i < gamepad.axes.length; i++) {
        const axis = gamepad.axes[i];
        const mapping = data.axesMappings[i];
        this.updateButton(axis, mapping);
      }
    }

    if (this._editor) {
      this._editor.update(gamepads);
    }

    for (const key of this.keysPressedThisFrame) {
      if (!this.oldKeysPressed.has(key)) {
        this.dispatchKey(key, true);
      }
    }
    for (const key of this.oldKeysPressed) {
      if (!this.keysPressedThisFrame.has(key)) {
        this.dispatchKey(key, false);
      }
    }

    for (const button of this.mouseButtonsPressedThisFrame) {
      if (!this.oldMouseButtonsPressed.has(button)) {
        this.dispatchMouse(button, true);
      }
    }
    for (const button of this.oldMouseButtonsPressed) {
      if (!this.mouseButtonsPressedThisFrame.has(button)) {
        this.dispatchMouse(button, false);
      }
    }

    if (this.virtualCursor.modified) {
      this.virtualCursor.modified = false;
      if (this.virtualCursor.x > this.virtualCursor.maxX) {
        this.virtualCursor.x = this.virtualCursor.maxX;
      }
      if (this.virtualCursor.x < this.virtualCursor.minX) {
        this.virtualCursor.x = this.virtualCursor.minX;
      }
      if (this.virtualCursor.y > this.virtualCursor.maxY) {
        this.virtualCursor.y = this.virtualCursor.maxY;
      }
      if (this.virtualCursor.y < this.virtualCursor.minY) {
        this.virtualCursor.y = this.virtualCursor.minY;
      }
      this.dispatchMouseMove(this.virtualCursor.x, this.virtualCursor.y);
    }
  }
}

GamepadLib.browserHasBrokenGamepadAPI = () => {
  // Check that the gamepad API is supported at all
  if (!navigator.getGamepads) {
    return true;
  }
  // Firefox on Linux has a broken gamepad API implementation that results in strange and sometimes unusable mappings
  // https://bugzilla.mozilla.org/show_bug.cgi?id=1643358
  // https://bugzilla.mozilla.org/show_bug.cgi?id=1643835
  if (navigator.userAgent.includes("Firefox") && navigator.userAgent.includes("Linux")) {
    return true;
  }
  // Firefox on macOS has other bugs that result in strange and unusable mappings
  // eg. https://bugzilla.mozilla.org/show_bug.cgi?id=1434408
  if (navigator.userAgent.includes("Firefox") && navigator.userAgent.includes("Mac OS")) {
    return true;
  }
  return false;
};

GamepadLib.setConsole = (n) => (console = n);

export default GamepadLib;