const MAX_HISTORY_LENGTH = 32;
const PIP_WINDOW_SIZE = { width: 280, height: 140 };

class Counter {
    constructor(elementId, storageKey) {
        this.el = document.getElementById(elementId);
        this.key = storageKey;
        this.count = parseInt(localStorage.getItem(this.key)) || 0;
        this.history = [];
        this.render();
    }

    render = () => {
        this.el.textContent = this.count;
    }

    set = (val) => {
        this.history.push(this.count);
        if (this.history.length > MAX_HISTORY_LENGTH) this.history.shift();
        this.count = val;
        localStorage.setItem(this.key, this.count);
        this.render();
    }

    increase = () => {
        this.set(this.count + 1);
    }

    undo = () => {
        if (this.history.length > 0) {
            this.count = this.history.pop();
            localStorage.setItem(this.key, this.count);
            this.render();
        }
    }
}

const stitches = new Counter("stitches-counter", "stitches");
const rows = new Counter("rows-counter", "rows");

const inputAuto = document.getElementById("input-autoincrease");
const inputStitchMax = document.getElementById("input-stitches");

inputAuto.checked = localStorage.getItem("input_autoincrease") === "true";
inputStitchMax.value = localStorage.getItem("input_stitches") || "10";

inputAuto.addEventListener("change", () => {
    localStorage.setItem("input_autoincrease", inputAuto.checked);
});

inputStitchMax.addEventListener("change", () => {
    localStorage.setItem("input_stitches", inputStitchMax.value);
});

document.getElementById("button-stitch").addEventListener("click", () => {
    const max = parseInt(inputStitchMax.value);
    if (inputAuto.checked && stitches.count + 1 >= max) {
        rows.increase();
        stitches.set(0);
    } else {
        stitches.increase();
    }
});

document.getElementById("button-row").addEventListener("click", () => {
    rows.increase();
    stitches.set(0);
});

document.getElementById("button-undo").addEventListener("click", () => {
    stitches.undo();
    rows.undo();
});

document.getElementById("button-reset").addEventListener("click", () => {
    stitches.set(0);
    rows.set(0);
});

class PipManager {
    constructor(pipElement, pipContainer, pipButton) {
        this.el = pipElement;
        this.container = pipContainer;
        this.button = pipButton;
        this.pipWindow = null;

        this.button.addEventListener("click", this.start);
    }

    start = async () => {
        if (this.pipWindow && !this.pipWindow.closed) return;

        this.pipWindow = await documentPictureInPicture.requestWindow(PIP_WINDOW_SIZE);

        for (const styleSheet of document.styleSheets) {
            try {
                const style = document.createElement("style");
                const rules = Array.from(styleSheet.cssRules).map(r => r.cssText).join("");
                style.textContent = rules;
                this.pipWindow.document.head.appendChild(style);
            } catch {
                if (styleSheet.href) {
                    const link = document.createElement("link");
                    link.rel = "stylesheet";
                    link.href = styleSheet.href;
                    this.pipWindow.document.head.appendChild(link);
                }
            }
        }

        this.pipWindow.document.body.appendChild(this.el);

        // Add keydown listener inside PiP window
        this.pipWindow.addEventListener("keydown", (event) => {
            // Ignore if focused on input or textarea in PiP window
            const active = this.pipWindow.document.activeElement;
            if (active && (active.tagName === "INPUT" || active.tagName === "TEXTAREA")) return;

            if (event.code === "Space") {
                event.preventDefault();
                const max = parseInt(inputStitchMax.value);
                if (inputAuto.checked && stitches.count + 1 >= max) {
                    rows.increase();
                    stitches.set(0);
                } else {
                    stitches.increase();
                }
            }
        });

        this.pipWindow.addEventListener("pagehide", () => this.stop());
    }

    stop = () => {
        this.container.appendChild(this.el);
        this.pipWindow = null;
    }
}

new PipManager(
    document.getElementById("div-pip-element"),
    document.getElementById("div-pip-container"),
    document.getElementById("button-start-pip")
);

const notesField = document.getElementById("notes");
notesField.value = localStorage.getItem("notes") || "";
notesField.addEventListener("input", () => {
    localStorage.setItem("notes", notesField.value);
});

window.addEventListener("keydown", (event) => {
    // Ignore if focused on input or textarea, so typing space doesn't increment stitches accidentally
    const active = document.activeElement;
    if (active && (active.tagName === "INPUT" || active.tagName === "TEXTAREA")) return;

    if (event.code === "Space") {
        event.preventDefault();  // prevent page scroll on space key
        const max = parseInt(inputStitchMax.value);
        if (inputAuto.checked && stitches.count + 1 >= max) {
            rows.increase();
            stitches.set(0);
        } else {
            stitches.increase();
        }
    }
});