/**
 * @fileoverview This file implements the C1Pjs ROM component.
 * @author <a href="mailto:Jeff@pcjs.org">Jeff Parsons</a>
 * @version 1.0
 * Created 2012-Jun-15
 *
 * Copyright © 2012-2016 Jeff Parsons <Jeff@pcjs.org>
 *
 * This file is part of PCjs, a computer emulation software project at <http://pcjs.org/>.
 *
 * PCjs is free software: you can redistribute it and/or modify it under the terms of the
 * GNU General Public License as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 *
 * PCjs is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with PCjs.  If not,
 * see <http://www.gnu.org/licenses/gpl.html>.
 *
 * You are required to include the above copyright notice in every source code file of every
 * copy or modified version of this work, and to display that copyright notice on every screen
 * that loads or runs any version of this software (see COPYRIGHT in /modules/shared/lib/defines.js).
 *
 * Some PCjs files also attempt to load external resource files, such as character-image files,
 * ROM files, and disk image files. Those external resource files are not considered part of PCjs
 * for purposes of the GNU General Public License, and the author does not claim any copyright
 * as to their contents.
 */

"use strict";

if (NODE) {
    var str         = require("../../shared/lib/strlib");
    var web         = require("../../shared/lib/weblib");
    var DumpAPI     = require("../../shared/lib/dumpapi");
    var Component   = require("../../shared/lib/component");
}

/**
 * C1PROM(parmsROM)
 *
 * The ROM component expects the following (parmsROM) properties:
 *
 *      size: amount of ROM, in bytes
 *      image: name of ROM image file
 *
 * NOTE: The final location for the ROM image, once loaded, will be specified
 * by the Computer object, using the setBuffer() method.
 *
 * @constructor
 * @extends Component
 * @property {function()} convertImage
 */
function C1PROM(parmsROM)
{
    Component.call(this, "C1PROM", parmsROM);

    this.abMem = null;
    this.abImage = null;
    this.cbROM = parmsROM['size'];
    this.sImage = parmsROM['image'];
    if (this.sImage) {
        var sFileURL = this.sImage;
        /**
         * If the selected ROM image has a ".json" extension, then we assume it's a pre-converted
         * JSON-encoded ROM image, so we load it as-is; ditto for files with a ".hex" extension. Otherwise,
         * we ask our server-side ROM image converter to return the corresponding JSON-encoded data,
         * in compact form (ie, minimal whitespace, no ASCII data comments, etc).
         */
        var sFileExt = str.getExtension(this.sImage);
        if (sFileExt != DumpAPI.FORMAT.JSON && sFileExt != DumpAPI.FORMAT.HEX) {
            sFileURL = web.getHost() + DumpAPI.ENDPOINT + '?' + DumpAPI.QUERY.FILE + '=' + this.sImage + '&' + DumpAPI.QUERY.FORMAT + '=' + DumpAPI.FORMAT.BYTES;
        }
        var rom = this;
        web.getResource(sFileURL, null, true, function(sURL, sResponse, nErrorCode) {
            rom.convertImage(sURL, sResponse, nErrorCode);
        });
    }
}

Component.subclass(C1PROM);

/**
 * @this {C1PROM}
 * @param {Array} abMemory
 * @param {number} start
 * @param {number} end
 * @param {C1PCPU} cpu
 */
C1PROM.prototype.setBuffer = function(abMemory, start, end, cpu)
{
    this.abMem = abMemory;
    this.offROM = start;
    var cbROM = end - start + 1;
    /*
     * It's possible that the ROM component didn't specify a size,
     * in which case just use the size the Computer component has specified.
     */
    if (!this.cbROM)
        this.cbROM = cbROM;
    if (cbROM != this.cbROM) {
        this.setError("computer-specified ROM size (" + str.toHexWord(cbROM) + ") does not match component-specified size (" + str.toHexWord(this.cbROM) + ")");
        return;
    }
    if (cpu) {
        this.cpu = cpu;
        cpu.addWriteNotify(start, end, this, this.setByte);
    }
    this.copyImage();
};

/**
 * @this {C1PROM}
 * @param {boolean} fOn
 * @param {C1PComputer} cmp
 */
C1PROM.prototype.setPower = function(fOn, cmp)
{
    if (fOn && !this.flags.powered) {
        this.flags.powered = true;
        if (DEBUGGER) this.dbg = cmp.getComponentByType("debugger");
    }
};

/**
 * @this {C1PROM}
 * @param {number} addr
 * @param {number|undefined} [addrFrom]
 */
C1PROM.prototype.setByte = function(addr, addrFrom)
{
    /*
     * Beyond reporting this write, we need to "repair" the ROM, using the original image data,
     * but only if addrFrom is defined (undefined implies this is a write from the Debugger, and
     * we need to allow the Debugger to modify ROM contents).
     */
    if (addrFrom !== undefined) {
        if (DEBUGGER && this.dbg) this.dbg.messageIO(this, addr, addrFrom, this.dbg.MESSAGE_PORT, true);
        var offset = (addr - this.offROM);
        Component.assert(offset >= 0 && offset < this.cbROM);
        if (!this.abImage)
            this.abMem[this.offROM + offset] = 0;
        else
            this.abMem[this.offROM + offset] = this.abImage[offset];
    }
};

/**
 * @this {C1PROM}
 * @param {string} sImageName
 * @param {string} sImageData
 * @param {number} nErrorCode (response from server if anything other than 200)
 */
C1PROM.prototype.convertImage = function(sImageName, sImageData, nErrorCode)
{
    if (nErrorCode) {
        this.println("Error loading ROM \"" + sImageName + "\" (" + nErrorCode + ")");
        return;
    }
    if (sImageData.charAt(0) == "[" || sImageData.charAt(0) == "{") {
        try {
            /*
             * The most likely source of any exception will be here: parsing the JSON-encoded ROM data.
             */
            var rom = eval("(" + sImageData + ")");
            var ab = rom['bytes'];
            if (ab) {
                this.abImage = ab;
            } else {
                this.abImage = rom;
            }
        } catch (e) {
            this.println("Error processing ROM \"" + sImageName + "\": " + e.message);
            return;
        }
    }
    else {
        /*
         * Parse the ROM image data manually; we assume it's in "simplified" hex form (a series of hex byte-values separated by whitespace)
         */
        var sData = sImageData.replace(/\n/gm, " ").replace(/ +$/, "");
        var asData = sData.split(" ");
        this.abImage = new Array(asData.length);
        for (var i=0; i < asData.length; i++) {
            this.abImage[i] = parseInt(asData[i], 16);
        }
    }
    this.copyImage();
};

/**
 * @this {C1PROM}
 */
C1PROM.prototype.copyImage = function()
{
    /*
     * The Computer object may give us the address of the ROM image before we've finished downloading the image,
     * so both setBuffer() and convertImage() call copyImage(), which in turn will copy the image ONLY when both
     * pieces are in place.  At that point, the component becomes "ready", in much the same way that other components
     * (eg, CPU and Screen) become "ready" when all their prerequisites are satisfied.
     */
    if (!this.isReady()) {
        if (!this.sImage) {
            this.setReady();
        }
        else
        if (this.abImage && this.abMem) {
            var cbImage = this.abImage.length;
            if (cbImage != this.cbROM) {
                this.setError("ROM image size (" + str.toHexWord(cbImage) + ") does not match component-specified size (" + str.toHexWord(this.cbROM) + ")");
                return;
            }
            if (DEBUG) this.log("copyImage(): copying ROM to " + str.toHexWord(this.offROM) + " (" + str.toHexWord(cbImage) + " bytes)");
            for (var i=0; i < cbImage; i++) {
                this.abMem[this.offROM + i] = this.abImage[i];
            }
            this.setReady();
        }
    }
};

/**
 * C1PROM.init()
 *
 * This function operates on every HTML element of class "rom", extracting the
 * JSON-encoded parameters for the C1PROM constructor from the element's "data-value"
 * attribute, invoking the constructor to create a C1PROM component, and then binding
 * any associated HTML controls to the new component.
 */
C1PROM.init = function()
{
    var aeROM = Component.getElementsByClass(document, C1PJS.APPCLASS, "rom");
    for (var iROM=0; iROM < aeROM.length; iROM++) {
        var eROM = aeROM[iROM];
        var parmsROM = Component.getComponentParms(eROM);
        var rom = new C1PROM(parmsROM);
        Component.bindComponentControls(rom, eROM, C1PJS.APPCLASS);
    }
};

/*
 * Initialize all the ROM modules on the page.
 */
web.onInit(C1PROM.init);