import { basename } from "node:path";
import { format, inspect } from "node:util";
import { ansiColors, defaultLevelColor, logLevelValues } from "@lib/config";
import { format as formatDate } from "date-fns-tz";

import type {
	LogLevel,
	LogLevelValue,
	LoggerConfig,
	PatternContext,
	PatternTokens,
} from "@types";

function getTimestamp(config: Required<LoggerConfig>): {
	prettyTimestamp: string;
	timestamp: string;
} {
	const now = new Date();

	if (config.timezone === "local") {
		return {
			prettyTimestamp: formatDate(now, config.dateFormat),
			timestamp: now.toISOString(),
		};
	}

	return {
		prettyTimestamp: formatDate(now, config.dateFormat, {
			timeZone: config.timezone,
		}),
		timestamp: now.toISOString(),
	};
}

function getCallerInfo(config: Required<LoggerConfig>): {
	id: string;
	fileName: string;
	line: string;
	column: string;
	timestamp: string;
	prettyTimestamp: string;
} {
	const id = generateShortId();
	const timestampInfo = getTimestamp(config);
	const fallback = {
		id,
		fileName: "unknown",
		line: "0",
		column: "0",
		timestamp: timestampInfo.timestamp,
		prettyTimestamp: timestampInfo.prettyTimestamp,
	};

	const stack = new Error().stack;
	if (!stack) return fallback;

	const lines = stack.split("\n");

	for (let i = 1; i < lines.length; i++) {
		const line = lines[i].trim();

		// try file:// URLs first (works on all platforms)
		const fileURLMatch = line.match(
			/at\s+(?:.*\()?file:\/\/(.*):(\d+):(\d+)\)?/,
		);
		if (fileURLMatch) {
			const [_, fullPath, lineNumber, columnNumber] = fileURLMatch;
			const isInternal =
				fullPath.includes("atums.echo") || fullPath.includes("@atums/echo");

			if (isInternal) continue;

			return {
				id,
				fileName: basename(fullPath),
				line: lineNumber,
				column: columnNumber,
				timestamp: timestampInfo.timestamp,
				prettyTimestamp: timestampInfo.prettyTimestamp,
			};
		}

		const pathMatch = parseStackTracePath(line);
		if (pathMatch) {
			const { fullPath, lineNumber, columnNumber } = pathMatch;
			const isInternal =
				fullPath.includes("atums.echo") || fullPath.includes("@atums/echo");

			if (isInternal) continue;

			return {
				id,
				fileName: basename(fullPath),
				line: lineNumber,
				column: columnNumber,
				timestamp: timestampInfo.timestamp,
				prettyTimestamp: timestampInfo.prettyTimestamp,
			};
		}
	}

	return fallback;
}

function parseStackTracePath(line: string): {
	fullPath: string;
	lineNumber: string;
	columnNumber: string;
} | null {
	// remove "at " prefix and trim
	const cleanLine = line.replace(/^\s*at\s+/, "").trim();

	let pathPart: string;

	// extract path from parentheses if present
	const parenMatch = cleanLine.match(/\(([^)]+)\)$/);
	if (parenMatch) {
		pathPart = parenMatch[1];
	} else {
		pathPart = cleanLine;
	}

	let match: RegExpMatchArray | null = null;

	if (process.platform === "win32") {
		// windows-specific parsing
		// handle drive letters (C:) vs line numbers (:10:5)
		match = pathPart.match(
			/^((?:[a-zA-Z]:|\\\\[^\\]+\\[^\\]+|[^:]+)):(\d+):(\d+)$/,
		);

		if (!match) {
			// try alternative windows format with forward slashes
			match = pathPart.match(/^([a-zA-Z]:[^:]+):(\d+):(\d+)$/);
		}

		if (!match) {
			// try UNC path format
			match = pathPart.match(/^(\\\\[^:]+):(\d+):(\d+)$/);
		}
	} else {
		// unix-like systems (Linux, macOS)
		match = pathPart.match(/^([^:]+):(\d+):(\d+)$/);
	}

	if (match) {
		const [_, fullPath, lineNumber, columnNumber] = match;
		return {
			fullPath: fullPath.trim(),
			lineNumber,
			columnNumber,
		};
	}

	return null;
}

function generateShortId(length = 8): string {
	const chars =
		"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
	let id = "";

	for (let i = 0; i < length; i++) {
		const rand = Math.floor(Math.random() * chars.length);
		id += chars[rand];
	}

	return id;
}

function formatData(data: unknown, config: Required<LoggerConfig>): string {
	return config.prettyPrint && typeof data === "object" && data !== null
		? inspect(data, {
				depth: null,
				colors: config.consoleColor,
				breakLength: 1,
				compact: false,
			})
		: format(data);
}

function getConsoleMethod(level: LogLevel): "log" | "warn" | "error" {
	if (level === "error" || level === "fatal") return "error";
	if (level === "warn") return "warn";
	return "log";
}

function resolveColor(
	colorKey: string,
	config: Required<LoggerConfig>,
	level?: LogLevel,
	tag?: string,
): string {
	if (!config.consoleColor) return "";

	if (colorKey === "levelColor" && level) {
		const colorForLevel =
			config.levelColor?.[level] ?? defaultLevelColor[level];
		return ansiColors[colorForLevel ?? ""] ?? "";
	}

	if (colorKey === "tagColor" && tag) {
		const normalizedTag = tag.toUpperCase();
		return ansiColors[config.customColors?.[normalizedTag] ?? "green"] ?? "";
	}

	if (colorKey === "contextColor") {
		return ansiColors.cyan ?? "";
	}

	return ansiColors[colorKey] ?? "";
}

function serializeLogData(data: unknown): unknown {
	if (data instanceof Error) {
		return {
			name: data.name,
			message: data.message,
			stack: data.stack,
		};
	}

	if (
		typeof data === "string" ||
		typeof data === "number" ||
		typeof data === "boolean" ||
		data === null ||
		data === undefined
	) {
		return data;
	}

	if (typeof data === "object") {
		try {
			return JSON.parse(JSON.stringify(data));
		} catch (err) {
			if (
				(err instanceof TypeError && err.message.includes("circular")) ||
				(err instanceof Error && err.message.includes("cyclic"))
			) {
				return createSafeObjectRepresentation(data);
			}
			return String(data);
		}
	}

	return data;
}

function createSafeObjectRepresentation(
	obj: unknown,
	seen = new WeakSet(),
): unknown {
	if (obj === null || typeof obj !== "object") {
		return obj;
	}

	if (seen.has(obj as object)) {
		return "[Circular Reference]";
	}

	seen.add(obj as object);

	if (Array.isArray(obj)) {
		return obj.map((item) => createSafeObjectRepresentation(item, seen));
	}

	const result: Record<string, unknown> = {};
	for (const [key, value] of Object.entries(obj)) {
		try {
			result[key] = createSafeObjectRepresentation(value, seen);
		} catch {
			result[key] = "[Unserializable]";
		}
	}

	return result;
}

function processPattern(
	pattern: string,
	tokens: PatternTokens,
	config: Required<LoggerConfig>,
	level?: LogLevel,
	tag?: string,
): string {
	let processed = pattern;

	if (tokens.timestamp) {
		processed = processed.replace(/{timestamp}/g, tokens.timestamp);
	}
	if (tokens.prettyTimestamp) {
		processed = processed.replace(
			/{pretty-timestamp}/g,
			tokens.prettyTimestamp,
		);
	}
	if (tokens.levelName) {
		processed = processed.replace(/{level-name}/g, tokens.levelName);
	}
	if (tokens.level) {
		processed = processed.replace(/{level}/g, tokens.level);
	}
	if (tokens.fileName) {
		processed = processed.replace(/{file-name}/g, tokens.fileName);
	}
	if (tokens.line) {
		processed = processed.replace(/{line}/g, tokens.line);
	}
	if (tokens.column) {
		processed = processed.replace(/{column}/g, tokens.column);
	}
	if (tokens.data) {
		processed = processed.replace(/{data}/g, tokens.data);
	}
	if (tokens.id) {
		processed = processed.replace(/{id}/g, tokens.id);
	}
	if (tokens.tag) {
		processed = processed.replace(/{tag}/g, tokens.tag);
	}
	if (tokens.context) {
		processed = processed.replace(/{context}/g, tokens.context);
	}

	processed = processed.replace(/{color:(\w+)}/g, (_, colorKey) => {
		return resolveColor(colorKey, config, level, tag);
	});

	processed = processed.replace(
		/{reset}/g,
		config.consoleColor ? ansiColors.reset : "",
	);

	return processed;
}

function formatMultipleData(
	dataArray: unknown[],
	config: Required<LoggerConfig>,
): string {
	return dataArray.map((item) => formatData(item, config)).join(" ");
}

function parsePattern(ctx: PatternContext): string {
	const { level, data, config } = ctx;
	const { id, fileName, line, column, timestamp, prettyTimestamp } =
		getCallerInfo(config);

	const resolvedData: string = Array.isArray(data)
		? formatMultipleData(data, config)
		: formatData(data, config);

	const numericLevel: LogLevelValue = logLevelValues[level];
	const tokens: PatternTokens = {
		timestamp,
		prettyTimestamp,
		levelName: level.toUpperCase(),
		level: String(numericLevel),
		fileName,
		line,
		column,
		data: resolvedData,
		id,
	};
	return processPattern(config.pattern, tokens, config, level);
}

export {
	parsePattern,
	getCallerInfo,
	getTimestamp,
	generateShortId,
	formatData,
	getConsoleMethod,
	resolveColor,
	serializeLogData,
	processPattern,
};