import { BooleanFlag, Code, Constant, Metric, Setting, Severity } from "@clarity-types/data";
import { FunctionNames } from "@clarity-types/performance";
import * as clarity from "@src/clarity";
import * as core from "@src/core"
import { bind } from "@src/core/event";
import * as internal from "@src/diagnostic/internal";
import * as metric from "@src/data/metric";

let pushState = null;
let replaceState = null;
let url = null;
let count = 0;

export function start(): void {
    url = getCurrentUrl();
    count = 0;
    bind(window, "popstate", compute);

    // Add a proxy to history.pushState function
    if (pushState === null) { 
        pushState = history.pushState; 
        history.pushState = function(): void {
            pushState.apply(this, arguments);
            if (core.active() && check()) {
                compute();
            }
        };
    }

    // Add a proxy to history.replaceState function
    if (replaceState === null) 
    { 
        replaceState = history.replaceState; 
        history.replaceState = function(): void {
            replaceState.apply(this, arguments);
            if (core.active() && check()) {
                compute();
            }
        };
    }
}

function check(): boolean {
    if (count++ > Setting.CallStackDepth) {
        internal.log(Code.CallStackDepth, Severity.Info);
        return false;
    }
    return true;
}

function compute(): void {
    compute.dn = FunctionNames.HistoryCompute;
    count = 0; // Reset the counter
    if (url !== getCurrentUrl()) {
        // If the url changed, start tracking it as a new page
        clarity.stop();
        window.setTimeout(restart, Setting.RestartDelay);
    }
}

function restart(): void {
    clarity.start();
    metric.max(Metric.SinglePage, BooleanFlag.True);
}

function getCurrentUrl(): string {
    return location.href ? location.href.replace(location.hash, Constant.Empty) : location.href;
}

export function stop(): void {
    url = null;
    count = 0;
}