import chalk from "chalk";
import { setImmediate } from "node:timers";
import process from "node:process";

type Message = unknown;
type ChalkFunction = (...msgs: Message[]) => string;
type PrimitiveItems = Message[];

interface UnknownConversion<T> {
    condition: (arg: Message) => boolean;
    converter: (arg: T) => string;
}

interface WebLike {
    url?: string,
    headers?: Headers,
    method?: string
}

/** The first log message across all sources will not contain carriage return + newline control codes */
let first = true;

/**
 * A source for pretty and cool and fun logging
 */
class Logging {

    /** Can I be seen by the console and listeners? */
    visible: boolean
    /** What is my name? */
    source: string
    /** Should I use bright colors over dull ones? */
    bright: boolean = true;

    /** Control when logs are handled for this source - similar (defaults to) `LoggingConfiguration.logTiming` */
    logTiming: LogTiming = LoggingConfiguration.logTiming;
    /** Control how time is displayed for this source - similar (defaults to) `LoggingConfiguration.timeFormat` */
    timeFormat: TimeFormat = LoggingConfiguration.timeFormat;

    /**
     * Create a logging source
     * ```ts
     * const log = new Logging("Main");
     * 
     * log.i("Hello World!");
     * ```
     * @param source Module identifier. Used in every line to identify the module that sent the message.
     * @param silent Set to false to log a message when the logger instantiates. May be useful when debugging.
     * @returns A source for logging messages to the console (stdout). Functions for info, warnings, errors, debug statements, and network events are provided and have shorthands.
     */
    constructor(source: string, silent?: boolean, bright?: boolean) {
        this.visible = true;
        this.source = source;
        if (typeof bright == 'boolean') this.bright = bright;

        if (typeof silent == 'boolean' && !silent) this.info(`Instantiated logging for ${this.source}`);
    }

    #conversions(...msgs: PrimitiveItems) {
        const conversions = [
            {
                condition: arg => arg instanceof Error,
                converter: arg => arg.stack || arg.message
            } as UnknownConversion<Error>,
            {
                condition: arg => arg == null,
                converter: arg => JSON.stringify(arg)
            } as UnknownConversion<null>,
            {
                condition: arg => arg == undefined,
                converter: _arg => 'undefined'
            } as UnknownConversion<undefined>,
            {
                condition: arg => arg instanceof Response,
                converter: arg => {
                    try {
                        const url = arg.url.toString().length == 0 ? '(unknown origin) ' : new URL(arg.url);
                        const statusText = arg.statusText.length > 0 ? `${arg.statusText} ` : '';
                        
                        const shouldNewline = Array.from(arg.headers.keys()).length > 0;
                        const entries = Array.from(arg.headers.entries());
                        return (
                            `${arg.status} ${statusText}${url}${shouldNewline ? '\n  ' : ''}` +
                            entries.map(val => `${val[0]}: ${val[1]}`).join(`\n  `)
                        );
                    } catch {
                        return String(arg);
                    }
                }
            } as UnknownConversion<Response>,
            {
                condition: arg => arg instanceof Request,
                converter: arg => {
                    try {
                        const url = new URL(arg.url);
                        const shouldNewline = Array.from(arg.headers.keys()).length > 0;
                        const entries = Array.from(arg.headers.entries());
                        return `${arg.method} ${url}${shouldNewline ? '\n  ' : ''}${entries.map(val => `${val[0]}: ${val[1]}`).join(`\n  `)}`;
                    } catch {
                        return String(arg);
                    }
                }
            } as UnknownConversion<Request>,
            {
                condition: arg => typeof arg == 'object',
                converter: arg => JSON.stringify(arg)
            } as UnknownConversion<object>,
        ];
        function convertToString(arg: Message) {
            for (const conversion of conversions)
                if (conversion.condition(arg))
                    return (conversion.converter as (arg: unknown) => string)(arg);
            // gpt-4o idea cuz my brain has the `stupid` type

            return String(arg); // fallback
        }
        return msgs.map(val => convertToString(val)).join(' ');
    }
    #typeStr(type: MessageType) {
        switch (type) {
            case MessageType.Info:
                return '[INFO]';
            case MessageType.Warn:
                return '[WARN]';
            case MessageType.Error:
                return '[ERROR]';
            case MessageType.Debug:
                return '[DEBUG]';
            case MessageType.Network:
                return '[NETWORK]';
            default:
                return '[UNKNOWN]';
        }
    }
    #timeStr(time: Date) {
        switch (this.timeFormat) {
            case TimeFormat.Unix:
                return time.getTime();
            case TimeFormat.Local:
                return performance.now();
            case TimeFormat.RoundedLocal:
                return Math.round(performance.now());
            default:
                return time.toISOString();
        }
    }

    /**
     * Don't use this unless you're benchmarking.
     * 
     * Constructs a message. Does not do anything with it, or even return it.
     * 
     * Logging messages during [Deno] benchmarks causes problems.
     */
    bench(type: MessageType, chalkColor: ChalkFunction, ...msgs: PrimitiveItems) {
        `${chalk.gray(`${this.#timeStr(new Date())} `)} ${chalkColor(chalk.inverse(`${this.source} ${this.#typeStr(type)}`) + ` ${this.#conversions(...msgs)}`)}`;
    }
    #log(type: MessageType, chalkColor: ChalkFunction, ...msgs: PrimitiveItems) {
        if (!this.visible) return;
        const func = () => {

            const time = new Date();

            const str = this.#conversions(...msgs);
            const msg = `${chalk.gray(this.#timeStr(time))} ${chalkColor(chalk.inverse(`${this.source} ${this.#typeStr(type)}`) + ` ${str}`)}`

            process.stdout.write(`${first ? '' : '\r\n'}${msg}`);
            // I don't know if promise-ifying this helps or not.
            // deno-lint-ignore require-await
            (async () => {
                first = false;
            })();

            try {
                LoggingListeners.emit('basic', msg);
                LoggingListeners.emit('type', str, type, this.source, time);
            } catch (err) {
                process.stderr.write(`\r\n(FALLBACK ERROR) Callback failed! Stack: ${(err as Error).stack}`);
            }
        }

        if (this.logTiming == LogTiming.Sync) func();
        else setImmediate(func);
    }

    /**
     * 
     * @param type The kind of message to log
     * @param msgs Your message(s)
     */
    log(type: MessageType, ...msgs: PrimitiveItems) {
        switch (type) {
            case MessageType.Info:
                this.info(...msgs);
                break;
            case MessageType.Warn:
                this.warn(...msgs);
                break;
            case MessageType.Error:
                this.error(...msgs);
                break;
            case MessageType.Debug:
                this.debug(...msgs);
                break;
            case MessageType.Network:
                this.network(...msgs);
                break;
            default:
                this.info(...msgs);
                break;
        }
    }

    /** Logging Function */
    i(...msgs: PrimitiveItems) { this.info(...msgs); }
    /** Logging Function */
    info(...msgs: PrimitiveItems) {
        if (!MessageTypeVisibility.Info) return;
        this.#log(MessageType.Info, chalk.whiteBright, ...msgs);
    }

    /** Logging Function */
    w(...msgs: PrimitiveItems) { this.warn(...msgs); }
    /** Logging Function */
    warn(...msgs: PrimitiveItems) {
        if (!MessageTypeVisibility.Warn) return;
        this.#log(MessageType.Warn, chalk.yellowBright, ...msgs);
    }

    /** Logging Function */
    e(...msgs: PrimitiveItems) { this.error(...msgs); }
    /** Logging Function */
    error(...msgs: PrimitiveItems) {
        if (!MessageTypeVisibility.Error) return;
        this.#log(MessageType.Error, chalk.redBright, ...msgs);
    }

    /** Logging Function */
    d(...msgs: PrimitiveItems) { this.debug(...msgs); }
    /** Logging Function */
    debug(...msgs: PrimitiveItems) {
        if (!MessageTypeVisibility.Debug) return;
        this.#log(MessageType.Debug, chalk.greenBright, ...msgs);
    }

    /** Logging Function */
    n(...msgs: PrimitiveItems) { this.network(...msgs); }
    /** Logging Function */
    network(...msgs: PrimitiveItems) {
        if (!MessageTypeVisibility.Network) return;
        this.#log(MessageType.Network, chalk.cyanBright, ...msgs);
    }

}

/** Useful for conditional logging with the `log` function */
enum MessageType {
    Info,
    Warn,
    Error,
    Debug,
    Network
}

/** Enable/disable logging of certain message types across all logging sources */
const MessageTypeVisibility = {
    Info: true,
    Warn: true,
    Error: true,
    Debug: true,
    Network: true
}

// 'On Message' event listeners
type BasicListener = (msg: string) => unknown;
type TypeListener = (msg: string, type: MessageType, source: string, time: Date) => unknown;
type Listener = BasicListener | TypeListener;
type ListenerType = 'basic' | 'type';

const basicListeners = new Set<Listener>();
const typeListeners = new Set<Listener>();

class ListenersBase {
    /** Register listener callback */
    onmsg(type: 'basic', cb: BasicListener): void
    onmsg(type: 'type', cb: TypeListener): void
    onmsg(type: ListenerType, cb: Listener) {
        if (type == 'basic') basicListeners.add(cb);
        else if (type == 'type') typeListeners.add(cb);
    }
    
    /** Remove listener callback */
    offmsg(type: 'basic', cb: BasicListener): void
    offmsg(type: 'type', cb: TypeListener): void
    offmsg(type: ListenerType, cb: Listener) {
        if (type == 'basic') basicListeners.delete(cb);
        else if (type == 'type') typeListeners.delete(cb);
    }

    /** Emit a log line. Usually not needed outside this module. */
    emit(type: 'basic', msg: string, msgtype?: MessageType, source?: string, time?: Date): void
    emit(type: 'type', msg: string, msgtype: MessageType, source: string, time: Date): void
    emit(type: ListenerType, msg: string, msgtype: MessageType, source: string, time: Date) {
        if (type == 'basic')
            for (const cb of basicListeners) (cb as BasicListener)(msg);
        if (type == 'type')
            for (const cb of typeListeners) (cb as TypeListener)(msg, msgtype, source, time);
    }
}
/**
 * Add/remove callbacks: run when something is logged anywhere
 */
const LoggingListeners: ListenersBase = new ListenersBase();

/**
 * Specify when, in/around the event loop, logs are sent
 */
enum LogTiming {
    Sync,
    Deferred
}
/**
 * Specify the format that loggers use to display time
 */
enum TimeFormat {
    Utc,
    Unix,
    Local,
    RoundedLocal
}

class LoggingConfigurationBase {

    #timing: LogTiming = LogTiming.Sync;

    #timeType: TimeFormat = TimeFormat.Utc;

    get timeFormat(): TimeFormat { return this.#timeType }
    set timeFormat(data: TimeFormat) { this.#timeType = data }

    get logTiming(): LogTiming { return this.#timing; }
    set logTiming(data: LogTiming) { this.#timing = data }

}
/**
 * Configure time display format and log timing here
 */
const LoggingConfiguration: LoggingConfigurationBase = new LoggingConfigurationBase();

export { MessageType, TimeFormat, LogTiming, MessageTypeVisibility, LoggingListeners, LoggingConfiguration };
export default Logging;