import { toast } from "./dom.js";
import { t } from "./i18n.js";

// Background parallax ------------------------------------------------
export function setupBackgroundPan(config = {}) {
    const root = document.documentElement;
    const maxOffset = config.maxOffsetPx ?? 30;
    const ease = config.ease ?? 0.08;
    const scaleFactor = config.scaleFactor ?? 1.12;
    if (scaleFactor) {
        root.style.setProperty("--bg-scale", scaleFactor);
    }
    let targetX = 0;
    let targetY = 0;
    let currX = 0;
    let currY = 0;

    const setTarget = (x, y) => {
        targetX = x;
        targetY = y;
    };

    const step = () => {
        currX += (targetX - currX) * ease;
        currY += (targetY - currY) * ease;
        root.style.setProperty("--bg-x", `${currX}px`);
        root.style.setProperty("--bg-y", `${currY}px`);
        requestAnimationFrame(step);
    };

    window.addEventListener("mousemove", (e) => {
        const nx = (e.clientX / window.innerWidth - 0.5) * 2;
        const ny = (e.clientY / window.innerHeight - 0.5) * 2;
        setTarget(-nx * maxOffset, -ny * maxOffset);
    });

    window.addEventListener("mouseleave", () => setTarget(0, 0));
    window.addEventListener("blur", () => setTarget(0, 0));
    step();
}

// Screenshot hover ---------------------------------------------------
export function setupCardVisualHover(el, url) {
    if (!el || !url) return;
    const img = new Image();
    let naturalW = 0;
    let naturalH = 0;
    let loaded = false;
    img.src = url;
    img.onload = () => {
        naturalW = img.naturalWidth;
        naturalH = img.naturalHeight;
        loaded = true;
    };

    const reset = () => {
        el.classList.remove("hovering");
        el.style.backgroundSize = "";
        el.style.backgroundPosition = "";
        el.style.backgroundRepeat = "";
    };

    el.addEventListener("mouseenter", () => {
        el.classList.add("hovering");
        el.style.backgroundSize = "auto";
        el.style.backgroundRepeat = "no-repeat";
        el.style.backgroundPosition = "center";
    });

    el.addEventListener("mousemove", (e) => {
        if (!loaded) return;
        const rect = el.getBoundingClientRect();
        const overW = naturalW - rect.width;
        const overH = naturalH - rect.height;
        if (overW <= 0 && overH <= 0) {
            el.style.backgroundPosition = "center";
            return;
        }
        const xRatio = (e.clientX - rect.left) / rect.width;
        const yRatio = (e.clientY - rect.top) / rect.height;
        const xPercent = overW > 0 ? xRatio * 100 : 50;
        const yPercent = overH > 0 ? yRatio * 100 : 50;
        el.style.backgroundPosition = `${xPercent}% ${yPercent}%`;
    });

    ["mouseleave", "blur"].forEach((evt) => el.addEventListener(evt, reset));
}

// Celebration FX -----------------------------------------------------
let fxCanvas;
let fxCtx;
let fxParticles = [];
let fxAnimating = false;

function ensureFxCanvas() {
    if (fxCanvas) return;
    fxCanvas = document.createElement("canvas");
    fxCanvas.className = "fx-canvas";
    fxCanvas.style.position = "fixed";
    fxCanvas.style.inset = "0";
    fxCanvas.style.pointerEvents = "none";
    fxCanvas.style.zIndex = "120";
    fxCanvas.width = window.innerWidth;
    fxCanvas.height = window.innerHeight;
    fxCtx = fxCanvas.getContext("2d");
    document.body.appendChild(fxCanvas);
    window.addEventListener("resize", () => {
        fxCanvas.width = window.innerWidth;
        fxCanvas.height = window.innerHeight;
    });
}

export function triggerCelebration(button) {
    ensureFxCanvas();
    const rect = (button || document.body).getBoundingClientRect();
    const x = rect.left + rect.width / 2;
    const y = rect.top + rect.height / 2;
    spawnConfetti(x, y, 80);
    spawnFirework(x, y, 40);
    if (!fxAnimating) {
        fxAnimating = true;
        requestAnimationFrame(fxStep);
    }
}

function spawnConfetti(x, y, count) {
    for (let i = 0; i < count; i++) {
        fxParticles.push({
            x: x + (Math.random() - 0.5) * 20,
            y: y + (Math.random() - 0.5) * 200,
            vx: (Math.random() - 0.5) * 6,
            vy: Math.random() * -6 - 2,
            size: 6 + Math.random() * 4,
            life: 600 + Math.random() * 200,
            color: randomColor(),
            type: "confetti",
            wobble: Math.random() * Math.PI * 2,
        });
    }
}

function spawnFirework(x, y, count) {
    for (let i = 0; i < count; i++) {
        const angle = (Math.PI * 2 * i) / count + Math.random() * 0.3;
        const speed = (3 + Math.random() * 3) * 0.1;
        fxParticles.push({
            x,
            y,
            vx: Math.cos(angle) * speed,
            vy: Math.sin(angle) * speed - 3,
            size: 4 + Math.random() * 3,
            life: 500 + Math.random() * 200,
            color: randomColor(),
            type: "spark",
        });
    }
}

function fxStep() {
    if (!fxCtx || !fxCanvas) return;
    fxCtx.clearRect(0, 0, fxCanvas.width, fxCanvas.height);
    fxParticles = fxParticles.filter((p) => p.life > 0);
    for (const p of fxParticles) {
        if (p.type === "confetti") {
            p.vy += 0.05;
            p.vx *= 0.999;
            p.wobble += 0.2;
            p.x += p.vx + Math.cos(p.wobble) * 0.8;
            p.y += p.vy;
        } else {
            p.vy += 0.02;
            p.vx *= 0.9995;
            p.x += p.vx;
            p.y += p.vy;
        }
        p.life -= 1;
        fxCtx.fillStyle = p.color;
        fxCtx.beginPath();
        if (p.type === "confetti") {
            fxCtx.fillRect(p.x, p.y, p.size, p.size * 0.6);
        } else {
            fxCtx.arc(p.x, p.y, p.size * 0.5, 0, Math.PI * 2);
            fxCtx.fill();
        }
    }
    if (fxParticles.length > 0) {
        requestAnimationFrame(fxStep);
    } else {
        fxCtx.clearRect(0, 0, fxCanvas.width, fxCanvas.height);
        fxAnimating = false;
    }
}

function randomColor() {
    const palette = ["#ff595e", "#ffca3a", "#8ac926", "#1982c4", "#6a4c93"];
    return palette[Math.floor(Math.random() * palette.length)];
}