import { Plugin, setIcon, WorkspaceLeaf } from "obsidian";
import { DEFAULT_SETTINGS, TabPinSettings, TabPinSettingTab } from "./settings";

const BTN_CLASS = "tab-pin-toggle";
const PINNED_CLASS = "is-pinned";

export default class TabPinButtonPlugin extends Plugin {
	settings: TabPinSettings;
	private observer?: MutationObserver;
	private seenLeaves = new WeakSet<WorkspaceLeaf>();

	async onload() {
		this.settings = Object.assign({}, DEFAULT_SETTINGS, await this.loadData());

		this.addSettingTab(new TabPinSettingTab(this.app, this));
		this.applyHoverStyle();

		this.decorateAllTabHeaders();

		this.registerEvent(this.app.workspace.on("layout-change", () => this.onWorkspaceChange()));
		this.registerEvent(this.app.workspace.on("active-leaf-change", () => this.syncAllButtons()));

		this.observer = new MutationObserver(() => {
			this.decorateAllTabHeaders();
			this.syncAllButtons();
		});
		this.observer.observe(document.body, { childList: true, subtree: true });

		this.autoPinNewLeavesPass();
	}

	onunload() {
		this.observer?.disconnect();
		document.querySelectorAll<HTMLElement>(`.${BTN_CLASS}`).forEach((el) => el.remove());
	}

	async saveSettings() { await this.saveData(this.settings); }

	applyHoverStyle() {
		const root = document.documentElement;
		if (this.settings.showPinOnlyOnHover) {
			root.style.setProperty("--tab-pin-initial-opacity", "0");
			root.style.setProperty("--tab-pin-hover-opacity", "1");
		} else {
			root.style.setProperty("--tab-pin-initial-opacity", "0.7");
			root.style.setProperty("--tab-pin-hover-opacity", "1");
		}
	}

	private onWorkspaceChange() {
		this.decorateAllTabHeaders();
		this.syncAllButtons();
		this.autoPinNewLeavesPass();
	}

	private decorateAllTabHeaders() {
		const headers = document.querySelectorAll<HTMLElement>(".workspace-tab-header");
		headers.forEach((header) => {
			if (header.querySelector(`.${BTN_CLASS}`)) return;
			const inner = header.querySelector<HTMLElement>(".workspace-tab-header-inner") ?? header;

			const btn = inner.createSpan({ cls: BTN_CLASS });
			const closeBtn = inner.querySelector<HTMLElement>(".workspace-tab-header-inner-close-button");
			if (closeBtn) closeBtn.before(btn); else inner.appendChild(btn);

			btn.setAttribute("aria-label", "Toggle pin");
			btn.setAttribute("tabindex", "0");
			setIcon(btn, "pin");

			btn.addEventListener("click", (ev) => {
				ev.stopPropagation();
				ev.preventDefault();
				this.activateHeader(header);
				const leaf = this.app.workspace.activeLeaf as any;
				if (!leaf) return;
				const pinned = !!leaf?.pinned;
				if (typeof leaf.setPinned === "function") leaf.setPinned(!pinned);
				else this.toggleViaViewState(leaf as WorkspaceLeaf, !pinned);
				this.syncButtonForHeader(header);
			});

			btn.addEventListener("keydown", (e: KeyboardEvent) => {
				if (e.key === "Enter" || e.key === " ") {
					e.preventDefault();
					(btn as HTMLElement).click();
				}
			});
		});
	}

	private syncAllButtons() {
		document.querySelectorAll<HTMLElement>(".workspace-tab-header").forEach((h) => this.syncButtonForHeader(h));
	}

	private syncButtonForHeader(header: HTMLElement) {
		const btn = header.querySelector<HTMLElement>(`.${BTN_CLASS}`);
		if (!btn) return;
		const isPinned = this.isHeaderPinned(header);
		btn.classList.toggle(PINNED_CLASS, isPinned);
		btn.setAttribute("aria-pressed", isPinned ? "true" : "false");
		btn.title = isPinned ? "Unpin tab" : "Pin tab";

// hide if pinned
		if (this.isHeaderPinned(header)) {
			btn.style.display = "none";
		} else {
			btn.style.display = "";
		}
	}

	private isHeaderPinned(header: HTMLElement): boolean {
		if (header.classList.contains("mod-pinned")) return true;
		if (header.classList.contains("is-active")) {
			const leaf = this.app.workspace.activeLeaf as any;
			return !!leaf?.pinned;
		}
		return false;
	}

	private activateHeader(header: HTMLElement) {
		header.dispatchEvent(new MouseEvent("mousedown", { bubbles: true }));
		header.click();
	}

	private async toggleViaViewState(leaf: WorkspaceLeaf, toPinned: boolean) {
		const vs = await leaf.getViewState();
		await leaf.setViewState({ ...vs, pinned: toPinned });
	}

	private autoPinNewLeavesPass() {
		if (!this.settings.autoPinNewTabs) return;
		const leaves = this.app.workspace.getLeavesOfType?.("") || this.getAllLeavesFallback();
		for (const leaf of leaves) {
			if (this.seenLeaves.has(leaf)) continue;
			this.seenLeaves.add(leaf);
			const anyLeaf = leaf as any;
			const pinned = !!anyLeaf?.pinned;
			if (!pinned) {
				if (typeof anyLeaf.setPinned === "function") anyLeaf.setPinned(true);
				else this.toggleViaViewState(leaf, true);
			}
		}
		this.syncAllButtons();
	}

	private getAllLeavesFallback(): WorkspaceLeaf[] {
		const out: WorkspaceLeaf[] = [];
		const visit: any = (container: any) => {
			if (!container) return;
			if (Array.isArray(container.children)) container.children.forEach(visit);
			if (container?.view && container?.leaf) out.push(container.leaf as WorkspaceLeaf);
			if (container?.leaves) container.leaves.forEach((l: WorkspaceLeaf) => out.push(l));
		};
		// @ts-expect-error accessing private rootSplit
		visit((this.app.workspace as any).rootSplit);
		return out;
	}
}