/**
 * Centralized Logger for Root Org
 * 
 * Works on both client and server. Outputs structured logs with:
 * - Timestamp
 * - Level (debug/info/warn/error)
 * - Context (which module/function)
 * - Structured data
 * 
 * On the server (dev terminal), logs are colorized and always visible.
 * On the client, logs go to console and can optionally trigger toasts.
 */

export type LogLevel = 'debug' | 'info' | 'warn' | 'error';

export interface LogEntry {
	level: LogLevel;
	context: string;
	message: string;
	data?: unknown;
	error?: unknown;
	timestamp: string;
}

const LEVEL_PRIORITY: Record<LogLevel, number> = {
	debug: 0,
	info: 1,
	warn: 2,
	error: 3,
};

const LEVEL_COLORS: Record<LogLevel, string> = {
	debug: '\x1b[36m',  // cyan
	info: '\x1b[32m',   // green
	warn: '\x1b[33m',   // yellow
	error: '\x1b[31m',  // red
};

const RESET = '\x1b[0m';
const BOLD = '\x1b[1m';
const DIM = '\x1b[2m';

// Minimum level to output — debug in dev, info in prod
let minLevel: LogLevel = typeof window !== 'undefined' && window.location?.hostname === 'localhost' ? 'debug' : 'info';

function shouldLog(level: LogLevel): boolean {
	return LEVEL_PRIORITY[level] >= LEVEL_PRIORITY[minLevel];
}

function isServer(): boolean {
	return typeof window === 'undefined';
}

function formatError(err: unknown): string {
	if (err instanceof Error) {
		const stack = err.stack ? `\n${err.stack}` : '';
		return `${err.name}: ${err.message}${stack}`;
	}
	if (typeof err === 'object' && err !== null) {
		try {
			return JSON.stringify(err, null, 2);
		} catch {
			return String(err);
		}
	}
	return String(err);
}

function formatData(data: unknown): string {
	if (data === undefined || data === null) return '';
	try {
		return JSON.stringify(data, null, 2);
	} catch {
		return String(data);
	}
}

function serverLog(entry: LogEntry) {
	const color = LEVEL_COLORS[entry.level];
	const levelTag = `${color}${BOLD}[${entry.level.toUpperCase()}]${RESET}`;
	const time = `${DIM}${entry.timestamp}${RESET}`;
	const ctx = `${color}[${entry.context}]${RESET}`;

	let line = `${levelTag} ${time} ${ctx} ${entry.message}`;

	if (entry.data !== undefined) {
		line += `\n  ${DIM}data:${RESET} ${formatData(entry.data)}`;
	}
	if (entry.error !== undefined) {
		line += `\n  ${color}error:${RESET} ${formatError(entry.error)}`;
	}

	// Use stderr for errors/warnings so they stand out in terminal
	if (entry.level === 'error') {
		console.error(line);
	} else if (entry.level === 'warn') {
		console.warn(line);
	} else {
		console.log(line);
	}
}

function clientLog(entry: LogEntry) {
	const prefix = `[${entry.level.toUpperCase()}] [${entry.context}]`;
	const args: unknown[] = [prefix, entry.message];

	if (entry.data !== undefined) args.push(entry.data);
	if (entry.error !== undefined) args.push(entry.error);

	switch (entry.level) {
		case 'error':
			console.error(...args);
			break;
		case 'warn':
			console.warn(...args);
			break;
		case 'debug':
			console.debug(...args);
			break;
		default:
			console.log(...args);
	}
}

function log(level: LogLevel, context: string, message: string, extra?: { data?: unknown; error?: unknown }) {
	if (!shouldLog(level)) return;

	const entry: LogEntry = {
		level,
		context,
		message,
		data: extra?.data,
		error: extra?.error,
		timestamp: new Date().toISOString(),
	};

	if (isServer()) {
		serverLog(entry);
	} else {
		clientLog(entry);
	}

	// Store in recent logs buffer for debugging
	recentLogs.push(entry);
	if (recentLogs.length > MAX_RECENT_LOGS) {
		recentLogs.shift();
	}

	return entry;
}

// Ring buffer of recent logs — useful for dumping context on crash
const MAX_RECENT_LOGS = 100;
const recentLogs: LogEntry[] = [];

/**
 * Create a scoped logger for a specific module/context.
 * 
 * Usage:
 * ```ts
 * const log = createLogger('kanban.api');
 * log.info('Loading board', { data: { boardId } });
 * log.error('Failed to load board', { error: err, data: { boardId } });
 * ```
 */
export function createLogger(context: string) {
	return {
		debug: (message: string, extra?: { data?: unknown; error?: unknown }) =>
			log('debug', context, message, extra),
		info: (message: string, extra?: { data?: unknown; error?: unknown }) =>
			log('info', context, message, extra),
		warn: (message: string, extra?: { data?: unknown; error?: unknown }) =>
			log('warn', context, message, extra),
		error: (message: string, extra?: { data?: unknown; error?: unknown }) =>
			log('error', context, message, extra),
	};
}

/** Set the minimum log level */
export function setLogLevel(level: LogLevel) {
	minLevel = level;
}

/** Get recent log entries (for error reports / debugging) */
export function getRecentLogs(): LogEntry[] {
	return [...recentLogs];
}

/** Clear recent logs */
export function clearRecentLogs() {
	recentLogs.length = 0;
}

/**
 * Format recent logs as a copyable string for bug reports.
 * User can paste this to you for debugging.
 */
export function dumpLogs(): string {
	return recentLogs
		.map((e) => {
			let line = `[${e.level.toUpperCase()}] ${e.timestamp} [${e.context}] ${e.message}`;
			if (e.data !== undefined) line += ` | data: ${formatData(e.data)}`;
			if (e.error !== undefined) line += ` | error: ${formatError(e.error)}`;
			return line;
		})
		.join('\n');
}