declare var __startCPUProfiler: any;
declare var __stopCPUProfiler: any;

import { TimerInfo as TimerInfoDefinition, InstrumentationMode } from ".";

export function uptime() {
    return global.android ? (<any>org).nativescript.Process.getUpTime() : (<any>global).__tns_uptime();
}

interface TimerInfo extends TimerInfoDefinition {
    totalTime: number;
    lastTime?: number;
    count: number;
    currentStart: number;
    /**
     * Counts the number of entry and exits a function had.
     */
    runCount: number;
}

// Use object instead of map as it is a bit faster
const timers: { [index: string]: TimerInfo } = {};
const anyGlobal = <any>global;
const profileNames: string[] = [];

export const time = (<any>global).__time || Date.now;

export function start(name: string): void {
    let info = timers[name];

    if (info) {
        info.currentStart = time();
        info.runCount++;
    } else {
        info = {
            totalTime: 0,
            count: 0,
            currentStart: time(),
            runCount: 1
        };
        timers[name] = info;
    }
}

export function stop(name: string): TimerInfo {
    const info = timers[name];

    if (!info) {
        throw new Error(`No timer started: ${name}`);
    }

    if (info.runCount) {
        info.runCount--;
        if (info.runCount) {
            info.count++;
        } else {
            info.lastTime = time() - info.currentStart;
            info.totalTime += info.lastTime;
            info.count++;
            info.currentStart = 0;
        }
    } else {
        throw new Error(`Timer ${name} paused more times than started.`);
    }

    return info;
}

export function timer(name: string): TimerInfo {
    return timers[name];
}

export function print(name: string): TimerInfo {
    const info = timers[name];
    if (!info) {
        throw new Error(`No timer started: ${name}`);
    }

    console.log(`---- [${name}] STOP total: ${info.totalTime} count:${info.count}`);
    return info;
}

export function isRunning(name: string): boolean {
    const info = timers[name];
    return !!(info && info.runCount);
}

function countersProfileFunctionFactory<F extends Function>(fn: F, name: string): F {
    profileNames.push(name);
    return <any>function() {
        start(name);
        try {
            return fn.apply(this, arguments);
        } finally {
            stop(name);
        }
    }
}

function timelineProfileFunctionFactory<F extends Function>(fn: F, name: string): F {
    return <any>function() {
        const start = time();
        try {
            return fn.apply(this, arguments);
        } finally {
            const end = time();
            console.log(`Timeline: Modules: ${name} ${this}  (${start}ms. - ${end}ms.)`);
        }
    }
}

let profileFunctionFactory: <F extends Function>(fn: F, name: string) => F;
export function enable(mode: InstrumentationMode = "counters") {
    profileFunctionFactory = mode && {
        counters: countersProfileFunctionFactory,
        timeline: timelineProfileFunctionFactory
    }[mode];
}

try {
    const appConfig = require("~/package.json");
    if (appConfig && appConfig.profiling) {
        enable(appConfig.profiling);
    }
} catch(e1) {
    try {
        console.log("Profiling startup failed to figure out defaults from package.json, error: " + e1);
    } catch(e2) {
        // We can get here if an exception is thrown in the mksnapshot as there is no console there.
    }
}

export function disable() {
    profileFunctionFactory = undefined;
}

function profileFunction<F extends Function>(fn: F, customName?: string): F {
    return profileFunctionFactory(fn, customName || fn.name);
}

const profileMethodUnnamed = (target, key, descriptor) => {
    // save a reference to the original method this way we keep the values currently in the
    // descriptor and don't overwrite what another decorator might have done to the descriptor.
    if (descriptor === undefined) {
        descriptor = Object.getOwnPropertyDescriptor(target, key);
    }
    var originalMethod = descriptor.value;

    let className = "";
    if (target && target.constructor && target.constructor.name) {
        className = target.constructor.name + ".";
    }

    let name = className + key;

    //editing the descriptor/value parameter
    descriptor.value = profileFunctionFactory(originalMethod, name);

    // return edited descriptor as opposed to overwriting the descriptor
    return descriptor;
}

function profileMethodNamed(name: string): MethodDecorator {
    return (target, key, descriptor: PropertyDescriptor) => {

        // save a reference to the original method this way we keep the values currently in the
        // descriptor and don't overwrite what another decorator might have done to the descriptor.
        if (descriptor === undefined) {
            descriptor = Object.getOwnPropertyDescriptor(target, key);
        }
        var originalMethod = descriptor.value;

        //editing the descriptor/value parameter
        descriptor.value = profileFunctionFactory(originalMethod, name);

        // return edited descriptor as opposed to overwriting the descriptor
        return descriptor;
    }
}

const voidMethodDecorator = () => {
    // no op
};

export function profile(nameFnOrTarget?: string | Function | Object, fnOrKey?: Function | string | symbol, descriptor?: PropertyDescriptor): Function | MethodDecorator {
    if (typeof nameFnOrTarget === "object" && (typeof fnOrKey === "string" || typeof fnOrKey === "symbol")) {
        if (!profileFunctionFactory) {
            return;
        }
        return profileMethodUnnamed(nameFnOrTarget, fnOrKey, descriptor);
    } else if (typeof nameFnOrTarget === "string" && typeof fnOrKey === "function") {
        if (!profileFunctionFactory) {
            return fnOrKey;
        }
        return profileFunction(fnOrKey, nameFnOrTarget);
    } else if (typeof nameFnOrTarget === "function") {
        if (!profileFunctionFactory) {
            return nameFnOrTarget;
        }
        return profileFunction(nameFnOrTarget);
    } else if (typeof nameFnOrTarget === "string") {
        if (!profileFunctionFactory) {
            return voidMethodDecorator;
        }
        return profileMethodNamed(nameFnOrTarget);
    } else {
        if (!profileFunctionFactory) {
            return voidMethodDecorator;
        }
        return profileMethodUnnamed;
    }
}

export function dumpProfiles(): void {
    profileNames.forEach(function (name) {
        const info = timers[name];
        if (info) {
            console.log("---- [" + name + "] STOP total: " + info.totalTime + " count:" + info.count);
        }
        else {
            console.log("---- [" + name + "] Never called");
        }
    });
}

export function resetProfiles(): void {
    profileNames.forEach(function (name) {
        const info = timers[name];
        if (info) {
            if (info.runCount) {
                console.log("---- timer with name [" + name + "] is currently running and won't be reset");
            } else {
                timers[name] = undefined;
            }
        }
    });
}

export function startCPUProfile(name: string) {
    if (anyGlobal.android) {
        __startCPUProfiler(name);
    }
}

export function stopCPUProfile(name: string) {
    if (anyGlobal.android) {
        __stopCPUProfiler(name);
    }
}