/* eslint-disable @typescript-eslint/unified-signatures */

/*!
 * V4Fire Core
 * https://github.com/V4Fire/Core
 *
 * Released under the MIT license
 * https://github.com/V4Fire/Core/blob/master/LICENSE
 */

/**
 * [[include:core/object/watch/README.md]]
 * @packageDocumentation
 */

import watchEngine from 'core/object/watch/engines';

import { muteLabel, toOriginalObject, toRootObject, watchHandlers } from 'core/object/watch/const';
import { isValueCanBeArrayIndex } from 'core/object/watch/helpers';
import { unwrap } from 'core/object/watch/engines/helpers';

import type {

	WatchPath,
	WatchOptions,

	WatchHandler,
	RawWatchHandler,
	MultipleWatchHandler,

	Watcher,
	WatchHandlersSet,
	WatchEngine

} from 'core/object/watch/interface';

export * from 'core/object/watch/const';
export { unwrap, isProxy, getProxyType } from 'core/object/watch/engines/helpers';
export * from 'core/object/watch/interface';

export default watch;

/**
 * Watches for changes of the specified object
 *
 * @param obj
 * @param [handler] - callback that is invoked on every mutation hook
 */
function watch<T extends object>(obj: T, handler?: MultipleWatchHandler): Watcher<T>;

/**
 * Watches for changes of the specified object
 *
 * @param obj
 * @param opts - additional options
 * @param [handler] - callback that is invoked on every mutation hook
 */
function watch<T extends object>(
	obj: T,
	opts: WatchOptions & {immediate: true},
	handler?: WatchHandler
): Watcher<T>;

/**
 * Watches for changes of the specified object
 *
 * @param obj
 * @param opts - additional options
 * @param [handler] - callback that is invoked on every mutation hook
 */
function watch<T extends object>(obj: T, opts: WatchOptions, handler?: MultipleWatchHandler): Watcher<T>;

/**
 * Watches for changes of the specified object
 *
 * @param obj
 * @param path - path to a property to watch
 * @param [handler] - callback that is invoked on every mutation hook
 */
function watch<T extends object>(
	obj: T,
	path: WatchPath,
	handler?: WatchHandler
): Watcher<T>;

/**
 * Watches for changes of the specified object
 *
 * @param obj
 * @param path - path to a property to watch
 * @param opts - additional options
 * @param [handler] - callback that is invoked on every mutation hook
 */
function watch<T extends object>(
	obj: T,
	path: WatchPath,
	opts: WatchOptions & ({collapse: false}),
	handler?: MultipleWatchHandler
): Watcher<T>;

/**
 * Watches for changes of the specified object
 *
 * @param obj
 * @param path - path to a property to watch
 * @param opts - additional options
 * @param [handler] - callback that is invoked on every mutation hook
 */
function watch<T extends object>(
	obj: T,
	path: WatchPath,
	opts: WatchOptions,
	handler?: MultipleWatchHandler
): Watcher<T>;

// eslint-disable-next-line max-lines-per-function
function watch<T extends object>(
	obj: T,
	pathOptsOrHandler?: WatchPath | WatchHandler | MultipleWatchHandler | WatchOptions,
	handlerOrOpts?: WatchHandler | MultipleWatchHandler | WatchOptions,
	optsOrHandler?: WatchOptions | WatchHandler | MultipleWatchHandler
): Watcher<T> {
	const
		isPathParsedFromString = Symbol('Is the path parsed from a string'),
		unwrappedObj = unwrap(obj);

	let
		wrappedHandler: CanUndef<WatchHandler>,
		handler: CanUndef<WatchHandler | MultipleWatchHandler>,
		opts: CanUndef<WatchOptions>;

	let
		timer,
		normalizedPath: CanUndef<unknown[]>;

	// Support for overloads of the function
	if (Object.isString(pathOptsOrHandler) || Object.isArray(pathOptsOrHandler)) {
		if (Object.isArray(pathOptsOrHandler)) {
			normalizedPath = pathOptsOrHandler;

		} else {
			normalizedPath = pathOptsOrHandler.split('.');
			normalizedPath[isPathParsedFromString] = true;
		}

		if (Object.isFunction(handlerOrOpts)) {
			handler = handlerOrOpts;

		} else {
			opts = handlerOrOpts;

			if (Object.isFunction(optsOrHandler)) {
				handler = optsOrHandler;
			}
		}

	} else if (Object.isFunction(pathOptsOrHandler)) {
		handler = pathOptsOrHandler;

	} else {
		opts = pathOptsOrHandler;

		if (Object.isFunction(handlerOrOpts)) {
			handler = handlerOrOpts;
		}
	}

	opts ??= {};
	opts.engine = opts.engine ?? watchEngine;

	const
		rawDeps = Object.size(opts.dependencies) > 0 ? opts.dependencies : undefined;

	let
		depsMap: CanUndef<Map<unknown[], unknown[][]>>,
		localDeps: CanUndef<unknown[]>,
		deps: CanUndef<unknown[][][]>;

	// Normalize dependencies
	if (rawDeps != null && unwrappedObj != null) {
		const convert = (dep) => {
			if (Object.isString(dep)) {
				dep = dep.split('.');
				dep[isPathParsedFromString] = true;
			}

			return dep;
		};

		if (Object.isArray(rawDeps)) {
			localDeps = [];

			if (normalizedPath != null) {
				for (let i = 0; i < rawDeps.length; i++) {
					localDeps.push(convert(rawDeps[i]));
				}
			}

		} else {
			deps = [];
			depsMap = new Map();

			Object.forEach(rawDeps, (dep, key) => {
				if (!Object.isArray(dep)) {
					throw new TypeError('Invalid format of dependencies');
				}

				let
					localDeps;

				if (Object.isArray(dep)) {
					localDeps = dep.slice();

					for (let i = 0; i < localDeps.length; i++) {
						localDeps[i] = convert(localDeps[i]);
					}

				} else {
					localDeps = [convert(dep)];
				}

				const
					path = convert(key);

				deps!.push([path, localDeps]);
				Object.set(depsMap, path, localDeps);
			});

			if (depsMap.size > 0) {
				const expandDeps = (deps) => {
					for (let i = 0; i < deps.length; i++) {
						const
							dep = Object.get(depsMap, deps[i]);

						if (dep != null) {
							deps.splice(i, 1, ...expandDeps(dep));
						}
					}

					return deps;
				};

				for (let i = 0; i < deps.length; i++) {
					expandDeps(deps[i][1]);
				}

				if (normalizedPath != null) {
					localDeps = Object.get(depsMap, normalizedPath);
				}
			}
		}
	}

	opts.deep = normalizedPath != null && normalizedPath.length > 1 || opts.deep;

	const
		{deep, collapse} = opts;

	const
		pref = opts.prefixes,
		post = opts.postfixes;

	const {
		immediate,
		withProto,
		tiedWith,

		pathModifier,
		eventFilter
	} = opts;

	// If we have a handler and valid object to watch,
	// we need to wrap this handler to provide all features of watching
	if (handler != null && unwrappedObj != null) {
		let
			dynamicValStore,
			argsQueue: any[] = [];

		wrappedHandler = (value, oldValue, info) => {
			const
				originalPath = info.path;

			if (pathModifier != null) {
				info = {...info, path: pathModifier(info.path)};
			}

			info.originalPath = originalPath;

			if (
				// We don't watch deep mutations
				!deep && info.path.length > (Object.isDictionary(info.obj) ? 1 : 2) ||

				// We don't watch prototype mutations
				!withProto && info.fromProto ||

				// The mutation is skipped by the filter
				eventFilter != null && !Object.isTruly(eventFilter(value, oldValue, info))
			) {
				return;
			}

			let
				cache;

			const fireMutationEvent = (tiedPath?, needGetVal = false) => {
				let
					resolvedInfo = info;

				// If we have a tied property with the property that have a mutation,
				// we need to register it
				if (tiedPath != null) {
					cache ??= new Map();

					if (Object.get(cache, tiedPath) === true) {
						return;
					}

					Object.set(cache, tiedPath, true);
					resolvedInfo = {
						...info,
						path: tiedPath.slice(),
						parent: {
							value,
							oldValue,
							info
						}
					};
				}

				// Returns a list of attributes to the mutation handler
				const getArgs = () => {
					if (needGetVal) {
						const
							dynamicVal = Object.get(unwrappedObj, collapse ? tiedPath[0] : tiedPath);

						if (Object.size(handler) < 2) {
							return [dynamicVal, undefined, resolvedInfo];
						}

						dynamicValStore ??= new Map();

						const args = [
							dynamicVal,
							Object.get(dynamicValStore, resolvedInfo.path),
							resolvedInfo
						];

						Object.set(dynamicValStore, resolvedInfo.path, dynamicVal);
						return args;
					}

					if (collapse) {
						const
							isRoot = resolvedInfo.obj === resolvedInfo.root;

						return [
							isRoot ? value : resolvedInfo.top,
							isRoot ? oldValue : resolvedInfo.top,
							resolvedInfo
						];
					}

					if (
						collapse !== false &&
						normalizedPath != null &&
						normalizedPath.length < resolvedInfo.originalPath.length
					) {
						const val = Object.get(unwrappedObj, normalizedPath);
						return [val, val, resolvedInfo];
					}

					return [value, oldValue, resolvedInfo];
				};

				if (immediate) {
					// eslint-disable-next-line prefer-spread
					handler!.apply(null, getArgs());

					// Deferred events
				} else {
					const
						needEventQueue = normalizedPath == null || collapse === false;

					if (needEventQueue) {
						argsQueue.push(getArgs());

					} else {
						argsQueue = getArgs();
					}

					if (timer == null) {
						timer = setImmediate(() => {
							timer = undefined;

							try {
								if (needEventQueue) {
									(<MultipleWatchHandler>handler)(argsQueue);

								} else {
									// eslint-disable-next-line prefer-spread
									(<WatchHandler>handler).apply(null, argsQueue);
								}

							} finally {
								argsQueue = [];
							}
						});
					}
				}
			};

			// Takes a tied path and checks if it matches with the actual path
			const checkTiedPath = (tiedPath: unknown[], deps: CanUndef<unknown[]>) => {
				const
					mutationPath = info.path,
					path = mutationPath.length > tiedPath.length ? mutationPath.slice(0, tiedPath.length) : mutationPath,
					tailPath = path.length !== tiedPath.length ? tiedPath.slice(path.length) : [];

				// Sometimes, we can be caught in the situation when we watch by the path, like, foo.bar.bla,
				// and the mutation occurs on foo.bar.
				// We need to get a value by the tail (.bla) and check that it really was changed.

				// const obj = {foo: {bar: {bla: 1}}}};
				// obj.foo.bar = {bla: 1};

				if (tailPath.length > 0) {
					const
						tailValue = Object.get(value, tailPath),
						tailOldValue = Object.get(oldValue, tailPath);

					if (tailValue === tailOldValue) {
						return;
					}

					if (!collapse) {
						value = tailValue;
						oldValue = tailOldValue;
					}
				}

				// The flag indicates that we need to get a real property value from the original object.
				// It makes sense for getters.
				let dynamic = false;

				path: for (let i = 0; i < path.length; i++) {
					const
						pathVal = path[i],
						tiedPathVal = tiedPath[i];

					const needNormalizeVal =
						Object.isNumber(pathVal) &&
						tiedPath[isPathParsedFromString] === true &&
						isValueCanBeArrayIndex(tiedPathVal);

					const pathsAreSame = needNormalizeVal ?
						Number(tiedPathVal) === Number(pathVal) :
						tiedPathVal === pathVal;

					if (pathsAreSame) {
						continue;
					}

					if (Object.isString(pathVal)) {
						const
							normalizedTiedPathVal = String(tiedPathVal);

						if (pref) {
							for (let i = 0; i < pref.length; i++) {
								if (pathVal === pref[i] + normalizedTiedPathVal) {
									dynamic = true;
									continue path;
								}
							}
						}

						if (post) {
							for (let i = 0; i < post.length; i++) {
								if (pathVal === normalizedTiedPathVal + post[i]) {
									dynamic = true;
									continue path;
								}
							}
						}
					}

					if (deps != null) {
						deps: for (let i = 0; i < deps.length; i++) {
							const
								depPath = deps[i];

							if (!Object.isArray(depPath)) {
								continue;
							}

							const
								path = info.path.length > depPath.length ? info.path.slice(0, depPath.length) : info.path;

							depsPath: for (let i = 0; i < path.length; i++) {
								const
									pathVal = path[i],
									depPathVal = depPath[i];

								const needNormalizeVal =
									Object.isNumber(pathVal) &&
									depPath[isPathParsedFromString] === true &&
									isValueCanBeArrayIndex(depPathVal);

								const pathsAreSame = needNormalizeVal ?
									Number(depPathVal) === Number(pathVal) :
									depPathVal === pathVal;

								if (pathsAreSame) {
									dynamic = true;
									continue;
								}

								if (Object.isString(pathVal)) {
									const
										normalizedDepPathVal = String(depPathVal);

									if (pref) {
										for (let i = 0; i < pref.length; i++) {
											if (pathVal === pref[i] + normalizedDepPathVal) {
												dynamic = true;
												continue depsPath;
											}
										}
									}

									if (post) {
										for (let i = 0; i < post.length; i++) {
											if (pathVal === normalizedDepPathVal + post[i]) {
												dynamic = true;
												continue depsPath;
											}
										}
									}
								}

								continue deps;
							}

							break path;
						}
					}

					// The path doesn't match with a tied path
					return;
				}

				fireMutationEvent(tiedPath, dynamic);
			};

			// We watch only the one specified property
			if (normalizedPath) {
				checkTiedPath(normalizedPath, localDeps);
				return;
			}

			fireMutationEvent();

			// Check if the mutation matches by prefixes/postfixes with another properties
			if (pref || post) {
				const
					tiedPath: unknown[] = [];

				let
					dynamic = false;

				path: for (let i = 0; i < info.path.length; i++) {
					const
						pathVal = info.path[i];

					if (Object.isString(pathVal)) {
						if (pref) {
							for (let i = 0; i < pref.length; i++) {
								const
									prefVal = pref[i];

								if (pathVal.startsWith(prefVal)) {
									dynamic = true;
									tiedPath.push(pathVal.slice(prefVal.length));
									continue path;
								}
							}
						}

						if (post) {
							for (let i = 0; i < post.length; i++) {
								const
									postVal = post[i];

								if (pathVal.endsWith(postVal)) {
									dynamic = true;
									tiedPath.push(pathVal.slice(0, -postVal.length));
									continue path;
								}
							}
						}

						tiedPath.push(pathVal);
					}
				}

				if (dynamic) {
					fireMutationEvent(tiedPath, true);
				}
			}

			// Check if the mutation matches by dependencies with another properties
			if (deps) {
				for (let i = 0; i < deps.length; i++) {
					const dep = deps[i];
					checkTiedPath(dep[0], dep[1]);
				}
			}
		};
	}

	const
		watcher = opts.engine.watch(obj, undefined, <RawWatchHandler>wrappedHandler, obj[watchHandlers] ?? new Set(), opts);

	const
		{proxy} = watcher;

	if (tiedWith && Object.isSimpleObject(unwrappedObj)) {
		tiedWith[watchHandlers] = proxy[watchHandlers];
		tiedWith[toOriginalObject] = proxy[toOriginalObject];

		for (let keys = Object.keys(proxy), i = 0; i < keys.length; i++) {
			const
				key = keys[i];

			if (Object.hasOwnProperty(tiedWith, key)) {
				continue;
			}

			Object.defineProperty(tiedWith, key, {
				configurable: true,
				enumerable: true,

				get(): unknown {
					return proxy[key];
				},

				set(val: unknown): void {
					proxy[key] = val;
				}
			});
		}
	}

	return watcher;
}

/**
 * The function temporarily mutes all mutation events for the specified proxy object
 *
 * @param obj
 * @example
 * ```js
 * const user = {
 *   name: 'Kobezzza',
 *   skills: {
 *     programming: 80,
 *     singing: 10
 *   }
 * };
 *
 * const {proxy} = watch(user, {immediate: true, deep: true}, (value, oldValue, info) => {
 *   console.log(value, oldValue, info.path);
 * });
 *
 * // 81 80 ['skills', 'programming']
 * proxy.skills.programming++;
 * mute(proxy);
 *
 * // This mutation won't invoke our callback
 * proxy.skills.programming++;
 * ```
 */
export function mute(obj: object): boolean {
	const
		root = unwrap(obj[toRootObject] ?? obj);

	if (root) {
		root[muteLabel] = true;
		return true;
	}

	return false;
}

/**
 * Wraps the specified object with unwatchable proxy, i.e. any mutations of this proxy can’t be watched
 *
 * @param obj
 * @example
 * ```js
 * const obj = {
 *   a: 1,
 *   b: unwatchable({c: 2})
 * };
 *
 * const {proxy} = watch(obj, {immediate: true}, (value, oldValue) => {
 *  console.log(value, oldValue);
 * });
 *
 * // This mutation will be ignored by the watcher
 * proxy.b.c = 3;
 *
 * // 1 2
 * proxy.a = 2;
 * ```
 */
export function unwatchable<T extends object>(obj: T): T {
	const {proxy} = watch(obj);
	mute(proxy);

	return proxy;
}

/**
 * The function unmutes all mutation events for the specified proxy object
 *
 * @param obj
 * @example
 * ```js
 * const user = {
 *   name: 'Kobezzza',
 *   skills: {
 *     programming: 80,
 *     singing: 10
 *   }
 * };
 *
 * const {proxy} = watch(user, {immediate: true, deep: true}, (value, oldValue, info) => {
 *   console.log(value, oldValue, info.path);
 * });
 *
 * // 81 80 ['skills', 'programming']
 * proxy.skills.programming++;
 * mute(proxy);
 *
 * // This mutation won't invoke our callback
 * proxy.skills.programming++;
 * unmute(proxy);
 *
 * // 83 82 ['skills', 'programming']
 * proxy.skills.programming++;
 * ```
 */
export function unmute(obj: object): boolean {
	const
		root = unwrap(obj[toRootObject] ?? obj);

	if (root) {
		root[muteLabel] = false;
		return true;
	}

	return false;
}

/**
 * Sets a new watchable value for a proxy object by the specified path.
 * The function is actual when using an engine based on accessors to add new properties to the watchable object.
 * Or when you want to restore watching for a property after deleting it.
 *
 * @param obj
 * @param path
 * @param value
 * @param [engine] - watch engine to use
 *
 * @example
 * ```js
 * const user = {
 *   name: 'Kobezzza',
 *   skills: {
 *     programming: 80,
 *     singing: 10
 *   }
 * };
 *
 * const {proxy} = watch(user, {immediate: true, deep: true}, (value, oldValue, info) => {
 *   console.log(value, oldValue, info.path);
 * });
 *
 * // This mutation will invoke our callback
 * set(proxy, 'bla.foo', 1);
 * ```
 */
export function set(
	obj: object,
	path: WatchPath,
	value: unknown,
	engine?: WatchEngine
): void;

/**
 * Sets a new watchable value for a proxy object by the specified path.
 * The function is actual when using an engine based on accessors to add new properties to the watchable object.
 * Or when you want to restore watching for a property after deleting it.
 *
 * @param obj
 * @param path
 * @param value
 * @param [handlers] - set of registered handlers
 * @param [engine] - watch engine to use
 */
export function set(
	obj: object,
	path: WatchPath,
	value: unknown,
	handlers: WatchHandlersSet,
	engine?: WatchEngine
): void;

export function set(
	obj: object,
	path: WatchPath,
	value: unknown,
	handlersOrEngine?: WatchHandlersSet | WatchEngine,
	engine: WatchEngine = watchEngine
): void {
	let
		handlers;

	if (Object.isSet(handlersOrEngine)) {
		handlers = handlersOrEngine;

	} else {
		engine = handlersOrEngine ?? engine;
		handlers = obj[watchHandlers];
	}

	engine.set(obj, path, value, handlers);
}

/**
 * Deletes a watchable value from a proxy object by the specified path
 *
 * @param obj
 * @param path
 * @param [engine] - watch engine to use
 *
 * @example
 * ```js
 * const user = {
 *   name: 'Kobezzza',
 *   skills: {
 *     programming: 80,
 *     singing: 10
 *   }
 * };
 *
 * const {proxy} = watch(user, {immediate: true, deep: true}, (value, oldValue, info) => {
 *   console.log(value, oldValue, info.path);
 * });
 *
 * // This mutation will invoke our callback
 * unset(proxy, 'skills.programming');
 *
 * console.log('programming' in proxy.skills === false);
 *
 * // This mutation won't invoke our callback
 * proxy.skills.programming = 80;
 *
 * // Invoke set to register a property to watch.
 * // This mutation will invoke our callback.
 * set(proxy, 'skills.programming', 80)
 *
 * // This mutation will invoke our callback
 * proxy.skills.programming++;
 * ```
 */
export function unset(
	obj: object,
	path: WatchPath,
	engine?: WatchEngine
): void;

/**
 * Deletes a watchable value from a proxy object by the specified path.
 * To restore watching for this property, use `set`.
 *
 * @param obj
 * @param path
 * @param [handlers] - set of registered handlers
 * @param [engine] - watch engine to use
 */
export function unset(
	obj: object,
	path: WatchPath,
	handlers: WatchHandlersSet,
	engine?: WatchEngine
): void;

export function unset(
	obj: object,
	path: WatchPath,
	handlersOrEngine?: WatchHandlersSet | WatchEngine,
	engine: WatchEngine = watchEngine
): void {
	let
		handlers;

	if (Object.isSet(handlersOrEngine)) {
		handlers = handlersOrEngine;

	} else {
		engine = handlersOrEngine ?? engine;
		handlers = obj[watchHandlers];
	}

	engine.unset(obj, path, handlers);
}