// Copyright 2024, Command Line Inc.
// SPDX-License-Identifier: Apache-2.0

import { WshServer } from "@/app/store/wshserver";
import {
    PLATFORM,
    WOS,
    atoms,
    fetchWaveFile,
    getFileSubject,
    globalStore,
    openLink,
    sendWSCommand,
} from "@/store/global";
import * as services from "@/store/services";
import * as util from "@/util/util";
import { base64ToArray, fireAndForget } from "@/util/util";
import { SerializeAddon } from "@xterm/addon-serialize";
import { WebLinksAddon } from "@xterm/addon-web-links";
import { WebglAddon } from "@xterm/addon-webgl";
import * as TermTypes from "@xterm/xterm";
import { Terminal } from "@xterm/xterm";
import debug from "debug";
import { debounce } from "throttle-debounce";
import { FitAddon } from "./fitaddon";

const dlog = debug("wave:termwrap");

const TermFileName = "term";
const TermCacheFileName = "cache:term:full";

// detect webgl support
function detectWebGLSupport(): boolean {
    try {
        const canvas = document.createElement("canvas");
        const ctx = canvas.getContext("webgl");
        return !!ctx;
    } catch (e) {
        return false;
    }
}

const WebGLSupported = detectWebGLSupport();
let loggedWebGL = false;

type TermWrapOptions = {
    keydownHandler?: (e: KeyboardEvent) => boolean;
    useWebGl?: boolean;
};

export class TermWrap {
    blockId: string;
    ptyOffset: number;
    dataBytesProcessed: number;
    terminal: Terminal;
    connectElem: HTMLDivElement;
    fitAddon: FitAddon;
    serializeAddon: SerializeAddon;
    mainFileSubject: SubjectWithRef<WSFileEventData>;
    loaded: boolean;
    heldData: Uint8Array[];
    handleResize_debounced: () => void;
    isRunning: boolean;
    hasResized: boolean;

    constructor(
        blockId: string,
        connectElem: HTMLDivElement,
        options: TermTypes.ITerminalOptions & TermTypes.ITerminalInitOnlyOptions,
        waveOptions: TermWrapOptions
    ) {
        this.loaded = false;
        this.blockId = blockId;
        this.ptyOffset = 0;
        this.dataBytesProcessed = 0;
        this.hasResized = false;
        this.terminal = new Terminal(options);
        this.fitAddon = new FitAddon();
        this.fitAddon.noScrollbar = PLATFORM == "darwin";
        this.serializeAddon = new SerializeAddon();
        this.terminal.loadAddon(this.fitAddon);
        this.terminal.loadAddon(this.serializeAddon);
        this.terminal.loadAddon(
            new WebLinksAddon((e, uri) => {
                e.preventDefault();
                switch (PLATFORM) {
                    case "darwin":
                        if (e.metaKey) {
                            fireAndForget(() => openLink(uri));
                        }
                        break;
                    default:
                        if (e.ctrlKey) {
                            fireAndForget(() => openLink(uri));
                        }
                        break;
                }
            })
        );
        if (WebGLSupported && waveOptions.useWebGl) {
            const webglAddon = new WebglAddon();
            webglAddon.onContextLoss(() => {
                webglAddon.dispose();
            });
            this.terminal.loadAddon(webglAddon);
            if (!loggedWebGL) {
                console.log("loaded webgl!");
                loggedWebGL = true;
            }
        }
        this.terminal.parser.registerOscHandler(7, (data: string) => {
            if (!this.loaded) {
                return false;
            }
            if (data == null || data.length == 0) {
                return false;
            }
            if (data.startsWith("file://")) {
                data = data.substring(7);
                const nextSlashIdx = data.indexOf("/");
                if (nextSlashIdx == -1) {
                    return false;
                }
                data = data.substring(nextSlashIdx);
            }
            setTimeout(() => {
                services.ObjectService.UpdateObjectMeta(WOS.makeORef("block", this.blockId), { "cmd:cwd": data });
            }, 0);
            return true;
        });
        this.terminal.attachCustomKeyEventHandler(waveOptions.keydownHandler);
        this.connectElem = connectElem;
        this.mainFileSubject = null;
        this.heldData = [];
        this.handleResize_debounced = debounce(50, this.handleResize.bind(this));
        this.terminal.open(this.connectElem);
        this.handleResize();
        this.isRunning = true;
    }

    async initTerminal() {
        this.terminal.onData(this.handleTermData.bind(this));
        this.mainFileSubject = getFileSubject(this.blockId, TermFileName);
        this.mainFileSubject.subscribe(this.handleNewFileSubjectData.bind(this));
        try {
            await this.loadInitialTerminalData();
        } finally {
            this.loaded = true;
        }
        this.runProcessIdleTimeout();
    }

    setIsRunning(isRunning: boolean) {
        this.isRunning = isRunning;
    }

    dispose() {
        this.terminal.dispose();
        this.mainFileSubject.release();
    }

    handleTermData(data: string) {
        const b64data = util.stringToBase64(data);
        WshServer.ControllerInputCommand({ blockid: this.blockId, inputdata64: b64data });
    }

    addFocusListener(focusFn: () => void) {
        this.terminal.textarea.addEventListener("focus", focusFn);
    }

    handleNewFileSubjectData(msg: WSFileEventData) {
        if (msg.fileop == "truncate") {
            this.terminal.clear();
            this.heldData = [];
        } else if (msg.fileop == "append") {
            const decodedData = base64ToArray(msg.data64);
            if (this.loaded) {
                this.doTerminalWrite(decodedData, null);
            } else {
                this.heldData.push(decodedData);
            }
        } else {
            console.log("bad fileop for terminal", msg);
            return;
        }
    }

    doTerminalWrite(data: string | Uint8Array, setPtyOffset?: number): Promise<void> {
        let resolve: () => void = null;
        let prtn = new Promise<void>((presolve, _) => {
            resolve = presolve;
        });
        this.terminal.write(data, () => {
            if (setPtyOffset != null) {
                this.ptyOffset = setPtyOffset;
            } else {
                this.ptyOffset += data.length;
                this.dataBytesProcessed += data.length;
            }
            resolve();
        });
        return prtn;
    }

    async loadInitialTerminalData(): Promise<void> {
        let startTs = Date.now();
        const { data: cacheData, fileInfo: cacheFile } = await fetchWaveFile(this.blockId, TermCacheFileName);
        let ptyOffset = 0;
        if (cacheFile != null) {
            ptyOffset = cacheFile.meta["ptyoffset"] ?? 0;
            if (cacheData.byteLength > 0) {
                this.doTerminalWrite(cacheData, ptyOffset);
            }
        }
        const { data: mainData, fileInfo: mainFile } = await fetchWaveFile(this.blockId, TermFileName, ptyOffset);
        console.log(
            `terminal loaded cachefile:${cacheData?.byteLength ?? 0} main:${mainData?.byteLength ?? 0} bytes, ${Date.now() - startTs}ms`
        );
        if (mainFile != null) {
            await this.doTerminalWrite(mainData, null);
        }
    }

    async resyncController(reason: string) {
        dlog("resync controller", this.blockId, reason);
        const tabId = globalStore.get(atoms.activeTabId);
        const rtOpts: RuntimeOpts = { termsize: { rows: this.terminal.rows, cols: this.terminal.cols } };
        try {
            await WshServer.ControllerResyncCommand({ tabid: tabId, blockid: this.blockId, rtopts: rtOpts });
        } catch (e) {
            console.log(`error controller resync (${reason})`, this.blockId, e);
        }
    }

    handleResize() {
        const oldRows = this.terminal.rows;
        const oldCols = this.terminal.cols;
        this.fitAddon.fit();
        if (oldRows !== this.terminal.rows || oldCols !== this.terminal.cols) {
            const termSize: TermSize = { rows: this.terminal.rows, cols: this.terminal.cols };
            const wsCommand: SetBlockTermSizeWSCommand = {
                wscommand: "setblocktermsize",
                blockid: this.blockId,
                termsize: termSize,
            };
            sendWSCommand(wsCommand);
        }
        dlog("resize", `${this.terminal.rows}x${this.terminal.cols}`, `${oldRows}x${oldCols}`, this.hasResized);
        if (!this.hasResized) {
            this.hasResized = true;
            this.resyncController("initial resize");
        }
    }

    processAndCacheData() {
        if (this.dataBytesProcessed < 10 * 1024) {
            return;
        }
        const serializedOutput = this.serializeAddon.serialize();
        console.log("idle timeout term", this.dataBytesProcessed, serializedOutput.length);
        services.BlockService.SaveTerminalState(this.blockId, serializedOutput, "full", this.ptyOffset);
        this.dataBytesProcessed = 0;
    }

    runProcessIdleTimeout() {
        setTimeout(() => {
            window.requestIdleCallback(() => {
                this.processAndCacheData();
                this.runProcessIdleTimeout();
            });
        }, 5000);
    }
}