// file: crates/ksp-app-config-desk/frontend/ts/splash.ts
// version: 3

import { listen } from "@tauri-apps/api/event";
import { getCurrentWindow } from "@tauri-apps/api/window";
import type { SplashOrderDto } from "./bindings/ksp_app_config_desk/splash/SplashOrderDto.ts";
import { frontendDebug, frontendError, frontendInfo, frontendTrace, installFrontendConsoleBridge } from "./frontend_log";
import { invokeKsp } from "./invoke";

installFrontendConsoleBridge("splash");

const defaultFadeDurationMs = 300;
let activeOpacityFrame: number | null = null;

function normalizeDurationMs(value: number | null | undefined): number {
    if (typeof value !== "number" || !Number.isFinite(value) || value <= 0) {
        return defaultFadeDurationMs;
    }
    return value;
}

function easeInOut(progress: number): number {
    if (progress < 0.5) {
        return 2 * progress * progress;
    }
    return 1 - Math.pow(-2 * progress + 2, 2) / 2;
}

async function animateOpacity(element: HTMLElement, fromOpacity: number, toOpacity: number, durationMs: number): Promise<void> {
    frontendTrace("splash", "Splash opacity animation started", { fromOpacity, toOpacity, durationMs });
    if (activeOpacityFrame !== null) {
        cancelAnimationFrame(activeOpacityFrame);
        activeOpacityFrame = null;
    }
    element.style.opacity = fromOpacity.toString();
    element.style.willChange = "opacity";
    await new Promise<void>(resolve => requestAnimationFrame(() => resolve()));
    await new Promise<void>(resolve => {
        const startedAt = performance.now();
        const opacityDelta = toOpacity - fromOpacity;
        const updateOpacity = (currentTime: number): void => {
            const elapsedMs = currentTime - startedAt;
            const rawProgress = Math.min(elapsedMs / durationMs, 1);
            element.style.opacity = (fromOpacity + opacityDelta * easeInOut(rawProgress)).toString();
            if (rawProgress >= 1) {
                element.style.opacity = toOpacity.toString();
                element.style.willChange = "auto";
                activeOpacityFrame = null;
                resolve();
                return;
            }
            activeOpacityFrame = requestAnimationFrame(updateOpacity);
        };
        activeOpacityFrame = requestAnimationFrame(updateOpacity);
    });
    frontendTrace("splash", "Splash opacity animation completed", { toOpacity, durationMs });
}

function replaceStatus(message: string | null): void {
    if (!message) {
        return;
    }
    const status = document.querySelector<HTMLElement>("#splash-status");
    if (status) {
        status.textContent = message;
        frontendTrace("splash", "Splash status replaced", { message });
    }
}

async function handleSplashOrder(order: SplashOrderDto): Promise<void> {
    frontendTrace("splash", "Splash order received", { action: order.action });
    const container = document.querySelector<HTMLElement>("#splash-container");
    replaceStatus(order.message);
    if (!container) {
        return;
    }
    if (order.action === "fade_in") {
        await animateOpacity(container, 0, 1, normalizeDurationMs(order.durationMs));
        return;
    }
    if (order.action === "fade_out") {
        await animateOpacity(container, 1, 0, normalizeDurationMs(order.durationMs));
    }
}

async function initializeSplash(): Promise<void> {
    const windowLabel = getCurrentWindow().label;
    frontendInfo("splash", "Config Desk splash frontend loaded", { windowLabel });
    const container = document.querySelector<HTMLElement>("#splash-container");
    if (container) {
        container.style.opacity = "0";
        container.style.willChange = "opacity";
        frontendTrace("splash", "Splash container prepared for managed fade-in");
    }
    await listen<SplashOrderDto>("ksp-splash-order", event => {
        void handleSplashOrder(event.payload);
    });
    frontendDebug("splash", "Splash lifecycle listener installed");
    try {
        await invokeKsp<void>("splash", "splash_frontend_ready");
    } catch {
        replaceStatus("Le lifecycle du splash n'a pas pu démarrer.");
        if (container) {
            container.style.opacity = "1";
            container.style.willChange = "auto";
        }
        frontendError("splash", "Splash readiness command failed");
    }
}

document.addEventListener("DOMContentLoaded", () => {
    void initializeSplash();
});