import { IElementState, IElementEffect } from "../types";
import { isArgsEqual } from "../util";

export const useEffectHook = (state: IElementState, fn: () => any, deps?: any[]) => {
    if (state.isFirstTick) {
        let dispose: any;
        try {
            dispose = fn();
        } catch (e) {
            state.error = e;
            return;
        }
        const newEffect: IElementEffect = {
            deps,
            dispose: dispose && typeof dispose === "function" ? dispose : undefined,
        };
        state.effects.push(newEffect);
        return;
    }
    const currentEffectNumber = state.tickState.currentEffectNumber;
    state.tickState.currentEffectNumber++;
    const effect = state.effects[currentEffectNumber];
    if (!effect) {
        throw new Error("Expected effect with number " + currentEffectNumber);
    }
    const existsDeps = effect.deps || [];
    const newDeps = deps || [];
    if (!(existsDeps.length === 0 && newDeps.length === 0) && existsDeps.length !== newDeps.length) {
        throw new Error("Dependencies not equal, old version of effect has dependencies and new version not has");
    }
    const isDepsEqual = isArgsEqual(effect.deps, deps);
    if (effect.deps && deps && isDepsEqual) {
        return;
    }
    if ((!effect.deps && !deps) || !isDepsEqual) {
        let dispose: any;
        try {
            dispose = fn();
        } catch (e) {
            state.error = e;
            return;
        }
        effect.dispose = dispose && typeof dispose === "function" ? dispose : undefined;
        effect.deps = deps;
    }
};