// Path: Frontend/src/components/shell/ProjectSelector/ProjectSelector.tsx

import { For, Show, createEffect, createMemo, createSignal, onCleanup, onMount, type JSX } from "solid-js";
import { ChevronDown, ChevronRight, Folder, LayoutGrid } from "../../../lib/icons";
import { ProjectContextMenu } from "../ProjectContextMenu/ProjectContextMenu";
import { useAppShellData } from "../data/app-shell.context";
import {
	createProjectFolderTarget,
	createProjectSurfaceTarget,
	createProjectTarget,
	type ProjectItem,
	type ProjectMenuTarget,
} from "../data/shell.data";
import { createProjectContextMenuController } from "../ProjectContextMenu/createProjectContextMenuController";
import styles from "./ProjectSelector.module.scss";

type ProjectSelectorProps = {
	compact?: boolean;
	isOpen: boolean;
	onToggle: () => void;
	onClose: () => void;
};

export const ProjectSelector = (props: ProjectSelectorProps): JSX.Element => {
	const appShellData = useAppShellData();
	const [selectedProject, setSelectedProject] = createSignal(appShellData.activeProject());
	const [drawerTop, setDrawerTop] = createSignal<number>(0);
	const [collapsedFolderIds, setCollapsedFolderIds] = createSignal<readonly string[]>([]);
	let rootRef: HTMLDivElement | undefined;
	let triggerRef: HTMLButtonElement | undefined;
	let contextMenuRef: HTMLDivElement | undefined;
	const contextMenu = createProjectContextMenuController();

	const projectFolders = createMemo(() => {
		const sections = new Map<string, ProjectItem[]>();

		for (const item of appShellData.projectItems()) {
			const key = item.parentLabel || item.groupLabel || "Projects";
			const existing = sections.get(key);

			if (existing) {
				existing.push(item);
				continue;
			}

			sections.set(key, [item]);
		}

		return Array.from(sections.entries()).map(([label, items]) => ({
			id: label.toLowerCase().replace(/\s+/g, "-"),
			label,
			meta: items[0]?.groupLabel && items[0].groupLabel !== label ? items[0].groupLabel : undefined,
			items,
		}));
	});

	const isFolderCollapsed = (folderId: string): boolean => collapsedFolderIds().includes(folderId);

	const toggleFolder = (folderId: string): void => {
		setCollapsedFolderIds((current) =>
			current.includes(folderId) ? current.filter((id) => id !== folderId) : [...current, folderId],
		);
	};

	createEffect(() => {
		setSelectedProject(appShellData.activeProject());
	});

	onMount(() => {
		if (triggerRef) {
			const updateDrawerTop = (): void => {
				if (!triggerRef) {
					return;
				}

				setDrawerTop(triggerRef.offsetTop + triggerRef.offsetHeight + 8);
			};

			updateDrawerTop();

			const observer = new ResizeObserver(() => {
				updateDrawerTop();
			});

			observer.observe(triggerRef);
			window.addEventListener("resize", updateDrawerTop);

			onCleanup(() => {
				observer.disconnect();
				window.removeEventListener("resize", updateDrawerTop);
			});
		}

		const handlePointerDown = (event: PointerEvent): void => {
			if (!props.isOpen || !rootRef) {
				return;
			}

			const target = event.target;

			if (target instanceof Node && rootRef.contains(target)) {
				return;
			}

			if (target instanceof Node && contextMenuRef?.contains(target)) {
				return;
			}

			props.onClose();
		};

		const handleEscape = (event: KeyboardEvent): void => {
			if (event.key !== "Escape" || !props.isOpen) {
				return;
			}

			props.onClose();
			triggerRef?.focus();
		};

		document.addEventListener("pointerdown", handlePointerDown);
		window.addEventListener("keydown", handleEscape);

		onCleanup(() => {
			document.removeEventListener("pointerdown", handlePointerDown);
			window.removeEventListener("keydown", handleEscape);
		});
	});

	const toggleOpen = (): void => {
		if (!props.isOpen) {
			props.onToggle();
			return;
		}

		props.onClose();
	};

	const selectProject = (projectId: string): void => {
		const nextProject = appShellData.projectItems().find((item): boolean => item.id === projectId);

		if (!nextProject) {
			return;
		}

		setSelectedProject({ id: nextProject.id, name: nextProject.name });
		props.onClose();
	};

	const handleContextActionSelect = (_action: { id: string; label: string }, _target: ProjectMenuTarget): void => {
		// Initial implementation keeps the project menu aligned with workspace-menu IA.
	};

	const handleSurfaceContextMenu = (event: MouseEvent): void => {
		event.stopPropagation();
		contextMenu.openMenu(event, createProjectSurfaceTarget("Projects"));
	};

	return (
		<div
			ref={rootRef}
			classList={{
				[styles.root]: true,
				[styles.rootCompact]: !!props.compact,
			}}
			style={{
				"--project-drawer-top": `${drawerTop()}px`,
			}}
		>
			<button
				type="button"
				ref={triggerRef}
				classList={{
					[styles.trigger]: true,
					[styles.triggerCompact]: !!props.compact,
					[styles.triggerOpen]: props.isOpen,
				}}
				aria-label={`Open project menu for ${selectedProject().name}`}
				aria-expanded={props.isOpen}
				aria-haspopup="menu"
				title={selectedProject().name}
				onClick={toggleOpen}
			>
				<span class={styles.triggerLead} aria-hidden="true">
					<Folder size={18} strokeWidth={2} />
				</span>
				{!props.compact ? (
					<span class={styles.triggerCopy}>
						<span class={styles.eyebrow}>Projects</span>
						<span class={styles.value}>{selectedProject().name}</span>
					</span>
				) : null}
				<ChevronDown
					classList={{
						[styles.triggerIcon]: true,
						[styles.triggerIconOpen]: props.isOpen,
					}}
					size={16}
					strokeWidth={2}
				/>
			</button>

			<Show when={props.isOpen}>
				<>
					<button
						type="button"
						classList={{
							[styles.scrim]: true,
							[styles.scrimOpen]: props.isOpen,
						}}
						aria-hidden={!props.isOpen}
						tabIndex={props.isOpen ? 0 : -1}
						onClick={props.onClose}
					/>

					<div
						classList={{
							[styles.drawer]: true,
							[styles.drawerOpen]: props.isOpen,
						}}
						aria-hidden={!props.isOpen}
						onContextMenu={handleSurfaceContextMenu}
					>
						<div class={styles.drawerBody}>
							<Show when={!props.compact}>
								<div class={styles.treeSectionLabel}>Projects</div>
							</Show>

							<ul class={styles.treeList} role="list">
								<For each={projectFolders()}>
									{(folder): JSX.Element => {
										const isCollapsed = (): boolean => isFolderCollapsed(folder.id);

										return (
										<li>
											<button
												type="button"
												classList={{
													[styles.treeItem]: true,
													[styles.treeItemFolder]: true,
												}}
												aria-expanded={!isCollapsed()}
												onClick={() => toggleFolder(folder.id)}
												onContextMenu={(event): void => {
													event.stopPropagation();
													contextMenu.openMenu(event, createProjectFolderTarget(folder.id, folder.label));
												}}
											>
												<ChevronRight
													classList={{
														[styles.folderChevron]: true,
														[styles.folderChevronOpen]: !isCollapsed(),
													}}
													size={16}
													strokeWidth={2}
												/>
												<Folder class={styles.icon} size={18} strokeWidth={2} />
												<span class={styles.label}>{folder.label}</span>
												<Show when={folder.meta}>
													<span class={styles.itemMeta}>{folder.meta}</span>
												</Show>
											</button>

											<Show when={!isCollapsed()}>
												<ul class={styles.treeList} role="list">
													<For each={folder.items}>
														{(item): JSX.Element => {
															const isSelected = (): boolean => selectedProject().id === item.id;

															return (
																<li>
																	<button
																		type="button"
																		classList={{
																			[styles.treeItem]: true,
																			[styles.treeItemActive]: isSelected(),
																		}}
																		style={{ "--tree-depth": "1" }}
																		onClick={(): void => selectProject(item.id)}
																		onContextMenu={(event): void => {
																			event.stopPropagation();
																			contextMenu.openMenu(event, createProjectTarget(item));
																		}}
																	>
																		<LayoutGrid class={styles.icon} size={18} strokeWidth={2} />
																		<span class={styles.label}>{item.name}</span>
																		<Show when={item.meta}>
																			<span class={styles.itemMeta}>{item.meta}</span>
																		</Show>
																	</button>
																</li>
															);
														}}
													</For>
												</ul>
											</Show>
										</li>
										);
									}}
								</For>
							</ul>
						</div>
					</div>
				</>
			</Show>

			<ProjectContextMenu
				target={contextMenu.menuState()?.target ?? null}
				position={(() => {
					const state = contextMenu.menuState();
					return state ? { x: state.x, y: state.y } : null;
				})()}
				menuRef={(element) => {
					contextMenuRef = element;
					contextMenu.setMenuRef(element);
				}}
				onClose={contextMenu.closeMenu}
				onSelect={handleContextActionSelect}
			/>
		</div>
	);
};