import { HotkeyDefinitionType, specialKeys } from './HotkeyDefinitionType';
import { HotkeyListener } from './HotkeyListener';
import { JsonHelper, ObjectHelper, Override } from '@ainias42/js-helper';
import { HotkeyEntry } from './HotkeyEntry';
import { SubKeyType } from './SubKeyType';
import { HotkeyPressedMap } from './HotkeyPressedMap';
import { HotkeyConfigWithOptionals } from './HotkeyConfigWithOptionals';

export class HotKeyManager<HotkeyConfig extends Record<string, HotkeyEntry<string>>> {
    private keyPressedMap = new Map<string, boolean>();
    private hotKeys: HotkeyConfig;
    private hotKeysPressedMap: HotkeyPressedMap<HotkeyConfig>;
    private enabled = true;
    private readonly ignoreFormElements: boolean = true;

    constructor(hotkeys: HotkeyConfigWithOptionals<HotkeyConfig>, ignoreFormElements?: boolean) {
        this.hotKeys = {} as HotkeyConfig;
        this.addHotKeys(hotkeys);

        if (ignoreFormElements !== undefined) {
            this.ignoreFormElements = ignoreFormElements;
        }
    }

    private static isFormElement(element: EventTarget | null) {
        return (
            element instanceof HTMLInputElement ||
            element instanceof HTMLSelectElement ||
            element instanceof HTMLTextAreaElement ||
            (element instanceof HTMLElement && element.contentEditable === 'true')
        );
    }

    private static isEqual(a: HotkeyDefinitionType, b: HotkeyDefinitionType) {
        return JsonHelper.deepEqual(a, b);
    }

    private static checkAffections(keyDefinitions: HotkeyDefinitionType[], key: string): boolean {
        return keyDefinitions.some((keyDefinition) => HotKeyManager.checkAffection(keyDefinition, key));
    }

    private static checkAffection(keyDefinition: HotkeyDefinitionType, key: string): boolean {
        return (
            keyDefinition.keys.includes(key) ||
            (key in specialKeys && keyDefinition[key as (typeof specialKeys)[number]] !== undefined)
        );
    }

    addHotKeys<NewHotkeyConfig extends Record<string, HotkeyEntry<string>>>(
        hotkeys: HotkeyConfigWithOptionals<NewHotkeyConfig>,
    ) {
        type NewConfig = Override<HotkeyConfig, NewHotkeyConfig>;

        this.hotKeys = {
            ...this.hotKeys,
            ...ObjectHelper.entries(hotkeys).reduce((acc, [key, value]) => {
                acc[key] = { subKeys: {}, callbacks: [], ...value } as unknown as NewConfig[typeof key];
                return acc;
            }, {} as NewConfig),
        };
        this.hotKeysPressedMap = this.generateHotkeyPressedMap();

        return this as unknown as HotKeyManager<NewConfig>;
    }

    addListener<HotkeyName extends keyof HotkeyConfig>(
        hotkeyName: HotkeyName,
        callback: HotkeyListener<SubKeyType<HotkeyConfig, HotkeyName>>,
    ) {
        const { callbacks } = this.hotKeys[hotkeyName];
        callbacks.push(callback);
        return () => {
            const index = callbacks.indexOf(callback);
            if (index > -1) {
                callbacks.splice(index, 1);
            }
        };
    }

    enable() {
        this.enabled = true;
    }

    disable() {
        this.enabled = false;
    }

    addHotKeyDefinition(hotkey: keyof HotkeyConfig, definition: HotkeyDefinitionType) {
        this.hotKeys[hotkey].keys.push(definition);
    }

    removeHotKeyDefinition(hotkey: keyof HotkeyConfig, definition: HotkeyDefinitionType) {
        this.hotKeys[hotkey].keys = this.hotKeys[hotkey].keys.filter((key) => !HotKeyManager.isEqual(key, definition));
    }

    setHotKeyDefinitions(hotkey: keyof HotkeyConfig, definitions: HotkeyDefinitionType[]) {
        this.hotKeys[hotkey].keys = definitions;
    }

    addSubKeyDefinition<HotkeyName extends keyof HotkeyConfig>(
        hotkey: HotkeyName,
        subKey: SubKeyType<HotkeyConfig, HotkeyName>,
        definition: HotkeyDefinitionType,
    ) {
        this.hotKeys[hotkey].subKeys[subKey as string].push(definition);
    }

    removeSubKeyDefinition<HotkeyName extends keyof HotkeyConfig>(
        hotkey: HotkeyName,
        subKey: SubKeyType<HotkeyConfig, HotkeyName>,
        definition: HotkeyDefinitionType,
    ) {
        const { subKeys } = this.hotKeys[hotkey];
        subKeys[subKey as string] = subKeys[subKey as string].filter((key) => !HotKeyManager.isEqual(key, definition));
    }

    setSubKeyDefinitions<HotkeyName extends keyof HotkeyConfig>(
        hotkey: HotkeyName,
        subKey: SubKeyType<HotkeyConfig, HotkeyName>,
        definitions: HotkeyDefinitionType[],
    ) {
        this.hotKeys[hotkey].subKeys[subKey as string] = definitions;
    }

    getConfig() {
        return this.hotKeys;
    }

    addKeyListeners() {
        window.addEventListener('keydown', (e) => {
            if (this.ignoreFormElements && HotKeyManager.isFormElement(e.target)) {
                return;
            }

            this.keyPressedMap.set(e.key.toLowerCase(), true);
            this.checkHotkeys(e);
        });
        window.addEventListener('keyup', (e) => {
            // Ignore the "ignoreFormFields" setting for keyup
            // Release should always trigger or else one hotkey can create form-field which is
            // focused and then it will never be released

            if (e.key === 'Meta') {
                this.clearMap(e);
            } else {
                this.keyPressedMap.set(e.key.toLowerCase(), false);
                this.checkHotkeys(e);
            }
        });
    }

    getHotKeysPressedMap() {
        return this.hotKeysPressedMap;
    }

    isHotKeyPressed(hotkey: keyof HotkeyConfig) {
        return this.hotKeysPressedMap[hotkey].isPressed;
    }

    isSubKeyPressed<Hotkey extends keyof HotkeyConfig>(hotkey: Hotkey, subkey: SubKeyType<HotkeyConfig, Hotkey>) {
        return this.hotKeysPressedMap[hotkey].isPressed && this.hotKeysPressedMap[hotkey].subKeys[subkey];
    }

    private checkHotkeyDefinitions(keyDefinitions: HotkeyDefinitionType[]): boolean {
        return keyDefinitions.some((keyDefinition) => this.checkHotkeyDefinition(keyDefinition));
    }

    private checkHotkeyDefinition(keyDefinition: HotkeyDefinitionType): boolean {
        if (!this.enabled) {
            return false;
        }

        if (keyDefinition.keys.some((key) => this.keyPressedMap.get(key) !== true)) {
            return false;
        }

        return !specialKeys.some(
            (key) => keyDefinition[key] !== undefined && !!this.keyPressedMap.get(key) !== keyDefinition[key],
        );
    }

    private generateHotkeyPressedMap() {
        return ObjectHelper.entries(this.hotKeys).reduce((acc, [key, value]) => {
            const isPressed = this.checkHotkeyDefinitions(value.keys);
            acc[key] = {
                isPressed,
                subKeys: ObjectHelper.keys(value.subKeys).reduce(
                    (accInner, subKey) => {
                        accInner[subKey as SubKeyType<HotkeyConfig, typeof key>] =
                            isPressed && this.checkHotkeyDefinitions(value.subKeys[subKey]);
                        return accInner;
                    },
                    {} as Record<SubKeyType<HotkeyConfig, typeof key>, boolean>,
                ),
            };
            return acc;
        }, {} as HotkeyPressedMap<HotkeyConfig>);
    }

    private triggerListenerFor(key: keyof HotkeyConfig, event: KeyboardEvent) {
        const pressedEntry = this.hotKeysPressedMap[key];
        this.hotKeys[key].callbacks.forEach((callback) =>
            callback({ event, subKeys: pressedEntry.subKeys, isPressed: pressedEntry.isPressed }),
        );
    }

    private checkHotkeys(event: KeyboardEvent) {
        const hotkeysToTrigger: (keyof HotkeyConfig)[] = [];

        const oldMap = this.hotKeysPressedMap;
        this.hotKeysPressedMap = this.generateHotkeyPressedMap();
        const hotkeysToCheckAffection = ObjectHelper.entries(this.hotKeysPressedMap).filter(([key, value]) => {
            const oldValue = oldMap[key];
            if (
                oldValue.isPressed !== value.isPressed ||
                (value.isPressed && !JsonHelper.deepEqual(oldValue.subKeys, value.subKeys))
            ) {
                hotkeysToTrigger.push(key);
                return false;
            }
            return value.isPressed;
        });

        // Check for repeated pressed. Nothing changed, but key is pressed again
        const eventKey = event.key.toLowerCase();
        hotkeysToCheckAffection.forEach(([key]) => {
            const keyDefinition = this.hotKeys[key];
            if (HotKeyManager.checkAffections(keyDefinition.keys, eventKey)) {
                hotkeysToTrigger.push(key);
            } else {
                ObjectHelper.values(keyDefinition.subKeys).forEach((subKeyDefinitions) => {
                    if (HotKeyManager.checkAffections(subKeyDefinitions, eventKey)) {
                        hotkeysToTrigger.push(key);
                    }
                });
            }
        });
        hotkeysToTrigger.forEach((key) => this.triggerListenerFor(key, event));
    }

    private clearMap(event: KeyboardEvent) {
        this.keyPressedMap.clear();
        this.checkHotkeys(event);
    }
}