/*
 * Tencent is pleased to support the open source community by making
 * Hippy available.
 *
 * Copyright (C) 2017-2019 THL A29 Limited, a Tencent company.
 * All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import {
  colors,
  Colors,
  matchers,
} from './constants';

function parse255(str: string) {
  const int = parseInt(str, 10);
  if (int < 0) {
    return 0;
  }
  if (int > 255) {
    return 255;
  }
  return int;
}

function parse1(str: string) {
  const num = parseFloat(str);
  if (num < 0) {
    return 0;
  }
  if (num > 1) {
    return 255;
  }
  return Math.round(num * 255);
}

function hue2rgb(p: number, q: number, tx: number) {
  let t = tx;
  if (t < 0) {
    t += 1;
  }
  if (t > 1) {
    t -= 1;
  }
  if (t < 1 / 6) {
    return p + (q - p) * 6 * t;
  }
  if (t < 1 / 2) {
    return q;
  }
  if (t < 2 / 3) {
    return p + (q - p) * (2 / 3 - t) * 6;
  }
  return p;
}

function hslToRgb(h: number, s: number, l: number) {
  const q = l < 0.5 ? l * (1 + s) : l + s - l * s;
  const p = 2 * l - q;
  const r = hue2rgb(p, q, h + 1 / 3);
  const g = hue2rgb(p, q, h);
  const b = hue2rgb(p, q, h - 1 / 3);
  return (
    (Math.round(r * 255) << 24)
    | (Math.round(g * 255) << 16)
    | (Math.round(b * 255) << 8)
  );
}

function parse360(str: string) {
  const int = parseFloat(str);
  return (((int % 360) + 360) % 360) / 360;
}

function parsePercentage(str: string) {
  const int = parseFloat(str);
  if (int < 0) {
    return 0;
  }
  if (int > 100) {
    return 1;
  }
  return int / 100;
}

function baseColor(color: string | keyof Colors) {
  let match;

  if (typeof color === 'number') {
    if (color >>> 0 === color && color >= 0 && color <= 0xffffffff) {
      return color;
    }
    return null;
  }
  match = matchers.hex6.exec(color);
  if (Array.isArray(match)) {
    return parseInt(`${match[1]}ff`, 16) >>> 0;
  }
  if (Object.hasOwnProperty.call(colors, color)) {
    return colors[color];
  }
  match = matchers.rgb.exec(color);
  if (Array.isArray(match)) {
    return (
      (parse255(match[1]) << 24) // r
      | (parse255(match[2]) << 16) // g
      | (parse255(match[3]) << 8) // b
      | 0x000000ff // a
    ) >>> 0;
  }
  match = matchers.rgba.exec(color);
  if (match) {
    return (
      (parse255(match[1]) << 24) // r
      | (parse255(match[2]) << 16) // g
      | (parse255(match[3]) << 8) // b
      | parse1(match[4]) // a
    ) >>> 0;
  }
  match = matchers.hex3.exec(color);
  if (match) {
    return parseInt(
      `${match[1] + match[1] // r
      + match[2] + match[2] // g
      + match[3] + match[3] // b
      }ff`, // a
      16,
    ) >>> 0;
  }
  match = matchers.hex8.exec(color);
  if (match) {
    return parseInt(match[1], 16) >>> 0;
  }
  match = matchers.hex4.exec(color);
  if (match) {
    return parseInt(
      match[1] + match[1] // r
      + match[2] + match[2] // g
      + match[3] + match[3] // b
      + match[4] + match[4], // a
      16,
    ) >>> 0;
  }
  match = matchers.hsl.exec(color);
  if (match) {
    return (
      hslToRgb(
        parse360(match[1]), // h
        parsePercentage(match[2]), // s
        parsePercentage(match[3]), // l
      )
      | 0x000000ff // a
    ) >>> 0;
  }
  match = matchers.hsla.exec(color);
  if (match) {
    return (
      hslToRgb(
        parse360(match[1]), // h
        parsePercentage(match[2]), // s
        parsePercentage(match[3]), // l
      )
      | parse1(match[4]) // a
    ) >>> 0;
  }
  return null;
}

export default baseColor;