/*
 * Copyright 2019, Gregg Tavares.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Gregg Tavares. nor the names of his
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/* global */
'use strict';

(function() {

  const lessonSettings = self.lessonSettings || {};

  function isInEditor() {
    return self.location.href.substring(0, 4) === 'blob';
  }

  function sendMessage(data) {
    self.postMessage({
      type: '__editor__',
      data,
    });
  }

  const origConsole = {};

  function setupConsole() {
    function wrapFunc(obj, logType) {
      const origFunc = obj[logType].bind(obj);
      origConsole[logType] = origFunc;
      return function(...args) {
        origFunc(...args);
        sendMessage({
          type: 'log',
          logType,
          msg: [...args].join(' '),
        });
      };
    }
    self.console.log = wrapFunc(self.console, 'log');
    self.console.warn = wrapFunc(self.console, 'warn');
    self.console.error = wrapFunc(self.console, 'error');
  }

  /**
   * Gets a WebGL context.
   * makes its backing store the size it is displayed.
   * @param {OffscreenCanvas} canvas a canvas element.
   * @memberOf module:webgl-utils
   */
  let setupLesson = function(canvas) {
    // only once
    setupLesson = function() {};

    if (canvas) {
      canvas.addEventListener('webglcontextlost', function(e) {
          // the default is to do nothing. Preventing the default
          // means allowing context to be restored
          e.preventDefault();
          sendMessage({
            type: 'lostContext',
          });
      });
    }

  };


  //------------ [ from https://github.com/KhronosGroup/WebGLDeveloperTools ]

  /*
  ** Copyright (c) 2012 The Khronos Group Inc.
  **
  ** Permission is hereby granted, free of charge, to any person obtaining a
  ** copy of this software and/or associated documentation files (the
  ** "Materials"), to deal in the Materials without restriction, including
  ** without limitation the rights to use, copy, modify, merge, publish,
  ** distribute, sublicense, and/or sell copies of the Materials, and to
  ** permit persons to whom the Materials are 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 Materials.
  **
  ** THE MATERIALS ARE 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
  ** MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.
  */

  /**
   * Types of contexts we have added to map
   */
  const mappedContextTypes = {};

  /**
   * Map of numbers to names.
   * @type {Object}
   */
  const glEnums = {};

  /**
   * Map of names to numbers.
   * @type {Object}
   */
  const enumStringToValue = {};

  /**
   * Initializes this module. Safe to call more than once.
   * @param {!WebGLRenderingContext} ctx A WebGL context. If
   *    you have more than one context it doesn't matter which one
   *    you pass in, it is only used to pull out constants.
   */
  function addEnumsForContext(ctx, type) {
    if (!mappedContextTypes[type]) {
      mappedContextTypes[type] = true;
      for (const propertyName in ctx) {
        if (typeof ctx[propertyName] === 'number') {
          glEnums[ctx[propertyName]] = propertyName;
          enumStringToValue[propertyName] = ctx[propertyName];
        }
      }
    }
  }

  function enumArrayToString(enums) {
    const enumStrings = [];
    if (enums.length) {
      for (let i = 0; i < enums.length; ++i) {
        enums.push(glEnumToString(enums[i]));  // eslint-disable-line
      }
      return '[' + enumStrings.join(', ') + ']';
    }
    return enumStrings.toString();
  }

  function makeBitFieldToStringFunc(enums) {
    return function(value) {
      let orResult = 0;
      const orEnums = [];
      for (let i = 0; i < enums.length; ++i) {
        const enumValue = enumStringToValue[enums[i]];
        if ((value & enumValue) !== 0) {
          orResult |= enumValue;
          orEnums.push(glEnumToString(enumValue));  // eslint-disable-line
        }
      }
      if (orResult === value) {
        return orEnums.join(' | ');
      } else {
        return glEnumToString(value);  // eslint-disable-line
      }
    };
  }

  const destBufferBitFieldToString = makeBitFieldToStringFunc([
    'COLOR_BUFFER_BIT',
    'DEPTH_BUFFER_BIT',
    'STENCIL_BUFFER_BIT',
  ]);

  /**
   * Which arguments are enums based on the number of arguments to the function.
   * So
   *    'texImage2D': {
   *       9: { 0:true, 2:true, 6:true, 7:true },
   *       6: { 0:true, 2:true, 3:true, 4:true },
   *    },
   *
   * means if there are 9 arguments then 6 and 7 are enums, if there are 6
   * arguments 3 and 4 are enums. Maybe a function as well in which case
   * value is passed to function and returns a string
   *
   * @type {!Object.<number, (!Object.<number, string>|function)}
   */
  const glValidEnumContexts = {
    // Generic setters and getters

    'enable': {1: { 0:true }},
    'disable': {1: { 0:true }},
    'getParameter': {1: { 0:true }},

    // Rendering

    'drawArrays': {3:{ 0:true }},
    'drawElements': {4:{ 0:true, 2:true }},
    'drawArraysInstanced': {4: { 0:true }},
    'drawElementsInstanced': {5: {0:true, 2: true }},
    'drawRangeElements': {6: {0:true, 4: true }},

    // Shaders

    'createShader': {1: { 0:true }},
    'getShaderParameter': {2: { 1:true }},
    'getProgramParameter': {2: { 1:true }},
    'getShaderPrecisionFormat': {2: { 0: true, 1:true }},

    // Vertex attributes

    'getVertexAttrib': {2: { 1:true }},
    'vertexAttribPointer': {6: { 2:true }},
    'vertexAttribIPointer': {5: { 2:true }},  // WebGL2

    // Textures

    'bindTexture': {2: { 0:true }},
    'activeTexture': {1: { 0:true }},
    'getTexParameter': {2: { 0:true, 1:true }},
    'texParameterf': {3: { 0:true, 1:true }},
    'texParameteri': {3: { 0:true, 1:true, 2:true }},
    'texImage2D': {
       9: { 0:true, 2:true, 6:true, 7:true },
       6: { 0:true, 2:true, 3:true, 4:true },
       10: { 0:true, 2:true, 6:true, 7:true },  // WebGL2
    },
    'texImage3D': {
      10: { 0:true, 2:true, 7:true, 8:true },  // WebGL2
      11: { 0:true, 2:true, 7:true, 8:true },  // WebGL2
    },
    'texSubImage2D': {
      9: { 0:true, 6:true, 7:true },
      7: { 0:true, 4:true, 5:true },
      10: { 0:true, 6:true, 7:true },  // WebGL2
    },
    'texSubImage3D': {
      11: { 0:true, 8:true, 9:true },  // WebGL2
      12: { 0:true, 8:true, 9:true },  // WebGL2
    },
    'texStorage2D': { 5: { 0:true, 2:true }},  // WebGL2
    'texStorage3D': { 6: { 0:true, 2:true }},  // WebGL2
    'copyTexImage2D': {8: { 0:true, 2:true }},
    'copyTexSubImage2D': {8: { 0:true }},
    'copyTexSubImage3D': {9: { 0:true }},  // WebGL2
    'generateMipmap': {1: { 0:true }},
    'compressedTexImage2D': {
      7: { 0: true, 2:true },
      8: { 0: true, 2:true },  // WebGL2
    },
    'compressedTexSubImage2D': {
      8: { 0: true, 6:true },
      9: { 0: true, 6:true },  // WebGL2
    },
    'compressedTexImage3D': {
      8: { 0: true, 2: true, },  // WebGL2
      9: { 0: true, 2: true, },  // WebGL2
    },
    'compressedTexSubImage3D': {
      9: { 0: true, 8: true, },  // WebGL2
      10: { 0: true, 8: true, },  // WebGL2
    },

    // Buffer objects

    'bindBuffer': {2: { 0:true }},
    'bufferData': {
      3: { 0:true, 2:true },
      4: { 0:true, 2:true },  // WebGL2
      5: { 0:true, 2:true },  // WebGL2
    },
    'bufferSubData': {
      3: { 0:true },
      4: { 0:true },  // WebGL2
      5: { 0:true },  // WebGL2
    },
    'copyBufferSubData': {
      5: { 0:true },  // WeBGL2
    },
    'getBufferParameter': {2: { 0:true, 1:true }},
    'getBufferSubData': {
      3: { 0: true, },  // WebGL2
      4: { 0: true, },  // WebGL2
      5: { 0: true, },  // WebGL2
    },

    // Renderbuffers and framebuffers

    'pixelStorei': {2: { 0:true, 1:true }},
    'readPixels': {
      7: { 4:true, 5:true },
      8: { 4:true, 5:true },  // WebGL2
    },
    'bindRenderbuffer': {2: { 0:true }},
    'bindFramebuffer': {2: { 0:true }},
    'blitFramebuffer': {10: { 8: destBufferBitFieldToString, 9:true }},  // WebGL2
    'checkFramebufferStatus': {1: { 0:true }},
    'framebufferRenderbuffer': {4: { 0:true, 1:true, 2:true }},
    'framebufferTexture2D': {5: { 0:true, 1:true, 2:true }},
    'framebufferTextureLayer': {5: {0:true, 1:true }},  // WebGL2
    'getFramebufferAttachmentParameter': {3: { 0:true, 1:true, 2:true }},
    'getInternalformatParameter': {3: {0:true, 1:true, 2:true }},  // WebGL2
    'getRenderbufferParameter': {2: { 0:true, 1:true }},
    'invalidateFramebuffer': {2: { 0:true, 1: enumArrayToString, }},  // WebGL2
    'invalidateSubFramebuffer': {6: {0: true, 1: enumArrayToString, }},  // WebGL2
    'readBuffer': {1: {0: true}},  // WebGL2
    'renderbufferStorage': {4: { 0:true, 1:true }},
    'renderbufferStorageMultisample': {5: { 0: true, 2: true }},  // WebGL2

    // Frame buffer operations (clear, blend, depth test, stencil)

    'clear': {1: { 0: destBufferBitFieldToString }},
    'depthFunc': {1: { 0:true }},
    'blendFunc': {2: { 0:true, 1:true }},
    'blendFuncSeparate': {4: { 0:true, 1:true, 2:true, 3:true }},
    'blendEquation': {1: { 0:true }},
    'blendEquationSeparate': {2: { 0:true, 1:true }},
    'stencilFunc': {3: { 0:true }},
    'stencilFuncSeparate': {4: { 0:true, 1:true }},
    'stencilMaskSeparate': {2: { 0:true }},
    'stencilOp': {3: { 0:true, 1:true, 2:true }},
    'stencilOpSeparate': {4: { 0:true, 1:true, 2:true, 3:true }},

    // Culling

    'cullFace': {1: { 0:true }},
    'frontFace': {1: { 0:true }},

    // ANGLE_instanced_arrays extension

    'drawArraysInstancedANGLE': {4: { 0:true }},
    'drawElementsInstancedANGLE': {5: { 0:true, 2:true }},

    // EXT_blend_minmax extension

    'blendEquationEXT': {1: { 0:true }},

    // Multiple Render Targets

    'drawBuffersWebGL': {1: {0: enumArrayToString, }},  // WEBGL_draw_bufers
    'drawBuffers': {1: {0: enumArrayToString, }},  // WebGL2
    'clearBufferfv': {
      4: {0: true },  // WebGL2
      5: {0: true },  // WebGL2
    },
    'clearBufferiv': {
      4: {0: true },  // WebGL2
      5: {0: true },  // WebGL2
    },
    'clearBufferuiv': {
      4: {0: true },  // WebGL2
      5: {0: true },  // WebGL2
    },
    'clearBufferfi': { 4: {0: true}},  // WebGL2

    // QueryObjects

    'beginQuery': { 2: { 0: true }},  // WebGL2
    'endQuery': { 1: { 0: true }},  // WebGL2
    'getQuery': { 2: { 0: true, 1: true }},  // WebGL2
    'getQueryParameter': { 2: { 1: true }},  // WebGL2

    //  Sampler Objects

    'samplerParameteri': { 3: { 1: true }},  // WebGL2
    'samplerParameterf': { 3: { 1: true }},  // WebGL2
    'getSamplerParameter': { 2: { 1: true }},  // WebGL2

    //  Sync objects

    'clientWaitSync': { 3: { 1: makeBitFieldToStringFunc(['SYNC_FLUSH_COMMANDS_BIT']) }},  // WebGL2
    'fenceSync': { 2: { 0: true }},  // WebGL2
    'getSyncParameter': { 2: { 1: true }},  // WebGL2

    //  Transform Feedback

    'bindTransformFeedback': { 2: { 0: true }},  // WebGL2
    'beginTransformFeedback': { 1: { 0: true }},  // WebGL2

    // Uniform Buffer Objects and Transform Feedback Buffers
    'bindBufferBase': { 3: { 0: true }},  // WebGL2
    'bindBufferRange': { 5: { 0: true }},  // WebGL2
    'getIndexedParameter': { 2: { 0: true }},  // WebGL2
    'getActiveUniforms': { 3: { 2: true }},  // WebGL2
    'getActiveUniformBlockParameter': { 3: { 2: true }},  // WebGL2
  };

  /**
   * Gets an string version of an WebGL enum.
   *
   * Example:
   *   var str = WebGLDebugUtil.glEnumToString(ctx.getError());
   *
   * @param {number} value Value to return an enum for
   * @return {string} The string version of the enum.
   */
  function glEnumToString(value) {
    const name = glEnums[value];
    return (name !== undefined) ? ('gl.' + name) :
        ('/*UNKNOWN WebGL ENUM*/ 0x' + value.toString(16) + '');
  }

  /**
   * Returns the string version of a WebGL argument.
   * Attempts to convert enum arguments to strings.
   * @param {string} functionName the name of the WebGL function.
   * @param {number} numArgs the number of arguments passed to the function.
   * @param {number} argumentIndx the index of the argument.
   * @param {*} value The value of the argument.
   * @return {string} The value as a string.
   */
  function glFunctionArgToString(functionName, numArgs, argumentIndex, value) {
    const funcInfos = glValidEnumContexts[functionName];
    if (funcInfos !== undefined) {
      const funcInfo = funcInfos[numArgs];
      if (funcInfo !== undefined) {
        const argType = funcInfo[argumentIndex];
        if (argType) {
          if (typeof argType === 'function') {
            return argType(value);
          } else {
            return glEnumToString(value);
          }
        }
      }
    }
    if (value === null) {
      return 'null';
    } else if (value === undefined) {
      return 'undefined';
    } else {
      return value.toString();
    }
  }

  /**
   * Converts the arguments of a WebGL function to a string.
   * Attempts to convert enum arguments to strings.
   *
   * @param {string} functionName the name of the WebGL function.
   * @param {number} args The arguments.
   * @return {string} The arguments as a string.
   */
  function glFunctionArgsToString(functionName, args) {
    // apparently we can't do args.join(",");
    const argStrs = [];
    const numArgs = args.length;
    for (let ii = 0; ii < numArgs; ++ii) {
      argStrs.push(glFunctionArgToString(functionName, numArgs, ii, args[ii]));
    }
    return argStrs.join(', ');
  }

  function makePropertyWrapper(wrapper, original, propertyName) {
    wrapper.__defineGetter__(propertyName, function() {  // eslint-disable-line
      return original[propertyName];
    });
    // TODO(gmane): this needs to handle properties that take more than
    // one value?
    wrapper.__defineSetter__(propertyName, function(value) {  // eslint-disable-line
      original[propertyName] = value;
    });
  }

  /**
   * Given a WebGL context returns a wrapped context that calls
   * gl.getError after every command and calls a function if the
   * result is not gl.NO_ERROR.
   *
   * @param {!WebGLRenderingContext} ctx The webgl context to
   *        wrap.
   * @param {!function(err, funcName, args): void} opt_onErrorFunc
   *        The function to call when gl.getError returns an
   *        error. If not specified the default function calls
   *        console.log with a message.
   * @param {!function(funcName, args): void} opt_onFunc The
   *        function to call when each webgl function is called.
   *        You can use this to log all calls for example.
   * @param {!WebGLRenderingContext} opt_err_ctx The webgl context
   *        to call getError on if different than ctx.
   */
  function makeDebugContext(ctx, options) {
    options = options || {};
    const errCtx = options.errCtx || ctx;
    const onFunc = options.funcFunc;
    const sharedState = options.sharedState || {
      numDrawCallsRemaining: options.maxDrawCalls || -1,
      wrappers: {},
    };
    options.sharedState = sharedState;

    const errorFunc = options.errorFunc || function(err, functionName, args) {
      console.error(`WebGL error ${glEnumToString(err)} in ${functionName}(${glFunctionArgsToString(functionName, args)})`);  /* eslint-disable-line no-console */
    };

    // Holds booleans for each GL error so after we get the error ourselves
    // we can still return it to the client app.
    const glErrorShadow = { };
    const wrapper = {};

    function removeChecks() {
      Object.keys(sharedState.wrappers).forEach(function(name) {
        const pair = sharedState.wrappers[name];
        const wrapper = pair.wrapper;
        const orig = pair.orig;
        for (const propertyName in wrapper) {
          if (typeof wrapper[propertyName] === 'function') {
            wrapper[propertyName] = orig[propertyName].bind(orig);
          }
        }
      });
    }

    function checkMaxDrawCalls() {
      if (sharedState.numDrawCallsRemaining === 0) {
        removeChecks();
      }
      --sharedState.numDrawCallsRemaining;
    }

    function noop() {
    }

    // Makes a function that calls a WebGL function and then calls getError.
    function makeErrorWrapper(ctx, functionName) {
      const check = functionName.substring(0, 4) === 'draw' ? checkMaxDrawCalls : noop;
      return function() {
        if (onFunc) {
          onFunc(functionName, arguments);
        }
        const result = ctx[functionName].apply(ctx, arguments);
        const err = errCtx.getError();
        if (err !== 0) {
          glErrorShadow[err] = true;
          errorFunc(err, functionName, arguments);
        }
        check();
        return result;
      };
    }

    function makeGetExtensionWrapper(ctx, wrapped) {
      return function() {
        const extensionName = arguments[0];
        let ext = sharedState.wrappers[extensionName];
        if (!ext) {
          ext = wrapped.apply(ctx, arguments);
          if (ext) {
            const origExt = ext;
            ext = makeDebugContext(ext, options);
            sharedState.wrappers[extensionName] = { wrapper: ext, orig: origExt };
            addEnumsForContext(origExt, extensionName);
          }
        }
        return ext;
      };
    }

    // Make a an object that has a copy of every property of the WebGL context
    // but wraps all functions.
    for (const propertyName in ctx) {
      if (typeof ctx[propertyName] === 'function') {
        if (propertyName !== 'getExtension') {
          wrapper[propertyName] = makeErrorWrapper(ctx, propertyName);
        } else {
          const wrapped = makeErrorWrapper(ctx, propertyName);
          wrapper[propertyName] = makeGetExtensionWrapper(ctx, wrapped);
        }
      } else {
        makePropertyWrapper(wrapper, ctx, propertyName);
      }
    }

    // Override the getError function with one that returns our saved results.
    if (wrapper.getError) {
      wrapper.getError = function() {
        for (const err in glErrorShadow) {
          if (glErrorShadow.hasOwnProperty(err)) {
            if (glErrorShadow[err]) {
              glErrorShadow[err] = false;
              return err;
            }
          }
        }
        return ctx.NO_ERROR;
      };
    }

    if (wrapper.bindBuffer) {
      sharedState.wrappers['webgl'] = { wrapper: wrapper, orig: ctx };
      addEnumsForContext(ctx, ctx.bindBufferBase ? 'WebGL2' : 'WebGL');
    }

    return wrapper;
  }

  //------------

  function captureJSErrors() {
    // capture JavaScript Errors
    self.addEventListener('error', function(e) {
      const msg = e.message || e.error;
      const url = e.filename;
      const lineNo = e.lineno || 1;
      const colNo = e.colno || 1;
      sendMessage({
        type: 'jsError',
        lineNo,
        colNo,
        url,
        msg,
      });
    });
  }


  const isWebGLRE = /^(webgl|webgl2|experimental-webgl)$/i;
  function installWebGLLessonSetup() {
    OffscreenCanvas.prototype.getContext = (function(oldFn) {
      return function() {
        const type = arguments[0];
        const isWebGL = isWebGLRE.test(type);
        if (isWebGL) {
          setupLesson(this);
        }
        const args = [].slice.apply(arguments);
        args[1] = Object.assign({
          powerPreference: 'low-power',
        }, args[1]);
        return oldFn.apply(this, args);
      };
    }(OffscreenCanvas.prototype.getContext));
  }

  function installWebGLDebugContextCreator() {
    // capture GL errors
    OffscreenCanvas.prototype.getContext = (function(oldFn) {
      return function() {
        let ctx = oldFn.apply(this, arguments);
        // Using bindTexture to see if it's WebGL. Could check for instanceof WebGLRenderingContext
        // but that might fail if wrapped by debugging extension
        if (ctx && ctx.bindTexture) {
          ctx = makeDebugContext(ctx, {
            maxDrawCalls: 100,
            errorFunc: function(err, funcName, args) {
              const numArgs = args.length;
              const enumedArgs = [].map.call(args, function(arg, ndx) {
                let str = glFunctionArgToString(funcName, numArgs, ndx, arg);
                // shorten because of long arrays
                if (str.length > 200) {
                  str = str.substring(0, 200) + '...';
                }
                return str;
              });

              {
                const error = new Error();
                sendMessage({
                  type: 'jsErrorWithStack',
                  stack: error.stack,
                  msg: `${glEnumToString(err)} in ${funcName}(${enumedArgs.join(', ')})`,
                });
              }
            },
          });
        }
        return ctx;
      };
    }(OffscreenCanvas.prototype.getContext));
  }

  installWebGLLessonSetup();

  if (isInEditor()) {
    setupConsole();
    captureJSErrors();
    if (lessonSettings.glDebug !== false) {
      installWebGLDebugContextCreator();
    }
  }

}());