"use client";
/**
 * THE SETTINGS DIALOG (settings-app wave, 2026-09-20): the thin settings
 * page graduated into the designed surface — a centered modal over
 * everything, left section nav + one scrolling content column.
 *
 * Owner decisions this wave:
 * - Dialog, not a page: opens over whatever screen you're on (the payoff:
 *   appearance edits restyle the chat LIVE behind the dialog). Escape,
 *   backdrop, and ✕ all close. Modal-only — /settings redirects, so
 *   nothing links into a dead surface.
 * - Left section nav in the app's mono chrome (text-only, session-list
 *   language — active = bg-accent), no icons, matching the minimal-color
 *   doctrine.
 * - The dialog is surface-agnostic by construction: the sections talk to
 *   /api/settings* and localStorage only, so this shell can be re-mounted
 *   as a true OS window in the Electron round with near-zero churn.
 *
 * The record + the single `write` seam moved here from the thin page:
 * one record instance for the whole dialog, sections write through it,
 * switching sections never refetches.
 */

import {
	createContext,
	useCallback,
	useContext,
	useEffect,
	useState,
} from "react";
import { createPortal } from "react-dom";
import {
	CURRENT_SETTINGS_VERSION,
	type AgentSettings,
	type AppearanceSettings,
	type GraphSettings,
	type UserSettings,
} from "@/src/core";
import { useAppearance } from "./appearance.tsx";
import { SettingsSection, SettingsRow, Toggle } from "./controls.tsx";
import { AgentSection } from "./agent-section.tsx";
import { AppearanceSection, GraphSection } from "./appearance-section.tsx";
import { KeyboardSection } from "./keyboard-section.tsx";

/** Owner (2026-09-20): hints earn their place — mechanics-explaining
 *  prose is out; only the keyboard note stays (storage location is a
 *  real question users ask). */
const SECTIONS = [
	{ id: "general", label: "General" },
	{ id: "agent", label: "Agent" },
	{ id: "appearance", label: "Appearance" },
	{ id: "graph", label: "Graph" },
	{ id: "keyboard", label: "Keyboard", hint: "Stored on this device" },
] as const;
type SectionId = (typeof SECTIONS)[number]["id"];

const DialogContext = createContext<{ open: () => void }>({ open: () => {} });

/** AppShell-level mount: the sidebar row and the mod+, chord call this. */
export function SettingsDialogProvider({
	children,
}: {
	children: React.ReactNode;
}) {
	const [show, setShow] = useState(false);
	const open = useCallback(() => setShow(true), []);
	return (
		<DialogContext.Provider value={{ open }}>
			{children}
			{show && <SettingsDialog onClose={() => setShow(false)} />}
		</DialogContext.Provider>
	);
}

export function useSettingsDialog() {
	return useContext(DialogContext);
}

function SettingsDialog({ onClose }: { onClose: () => void }) {
	// Plain dim backdrop (no blur — nothing decorative); the click
	// closes, the dialog body stops propagation.
	return createPortal(
		<div
			className="fixed inset-0 z-50 flex items-center justify-center bg-background/80"
			data-testid="settings-backdrop"
			onClick={onClose}
		>
			<SettingsDialogBody onClose={onClose} />
		</div>,
		document.body,
	);
}

/** The dialog without the portal/backdrop — the SSR-testable frame
 *  (portals render nothing under renderToStaticMarkup). */
export function SettingsDialogBody({ onClose }: { onClose: () => void }) {
	const { onAppearanceChange } = useAppearance();
	const [record, setRecord] = useState<UserSettings | null | undefined>(
		undefined,
	);
	const [error, setError] = useState<string | null>(null);
	const [active, setActive] = useState<SectionId>("general");

	// Fetch once per dialog mount. 200 {settings: null} is FIRST BOOT
	// (no record = factory everything), not a failure — the error state is
	// a non-200 or a network throw only.
	useEffect(() => {
		fetch("/api/settings")
			.then((r) =>
				r.ok ? r.json() : Promise.reject(new Error(`status ${r.status}`)),
			)
			.then((body: { settings: UserSettings | null }) =>
				setRecord(body.settings ?? { version: CURRENT_SETTINGS_VERSION }),
			)
			.catch(() => setRecord(null));
	}, []);

	// Escape closes — the layered-dismiss convention (Esc is dead for the
	// sections' own editors while they hold focus; this listener is the
	// dialog's outer layer).
	useEffect(() => {
		const onKey = (e: KeyboardEvent) => {
			if (e.key === "Escape") onClose();
		};
		window.addEventListener("keydown", onKey);
		return () => window.removeEventListener("keydown", onKey);
	}, [onClose]);

	/** ONE writer for the whole dialog: PUT the whole section, keep the
	 *  record mirror in sync, surface route errors inline (a 400 is a
	 *  schema mistake caught by the validation surface). */
	const write = useCallback(
		async (
			section: "general" | "agent" | "appearance" | "graph",
			body: object,
		) => {
			setError(null);
			const res = await fetch(`/api/settings/${section}`, {
				method: "PUT",
				headers: { "content-type": "application/json" },
				body: JSON.stringify(body),
			});
			if (!res.ok) {
				const detail = (await res.json().catch(() => ({}))) as {
					error?: string;
				};
				setError(`${section}: ${detail.error ?? res.status}`);
				return;
			}
			setRecord(
				(prev) => ({ ...(prev ?? {}), [section]: body }) as UserSettings,
			);
			if (section === "appearance")
				onAppearanceChange(body as AppearanceSettings);
		},
		[onAppearanceChange],
	);

	return (
		<div
			role="dialog"
			aria-modal="true"
			aria-label="Settings"
			data-testid="settings-dialog"
			className="settings-dialog-pop flex h-[620px] max-h-[85vh] w-[920px] max-w-[90vw] flex-col overflow-hidden rounded-md border border-border bg-card shadow-xl"
			onClick={(e) => e.stopPropagation()}
		>
			{/* Header — the app's quiet CMU title language. */}
			<header className="flex h-15 shrink-0 items-center gap-3 border-b border-border px-5">
				<h2 className="font-title text-2xl tracking-tight">Settings</h2>
				<button
					type="button"
					aria-label="Close settings"
					data-testid="settings-close"
					className="ml-auto size-7 rounded-sm text-muted-foreground transition-colors hover:bg-accent hover:text-foreground"
					onClick={onClose}
				>
					<svg
						viewBox="0 0 16 16"
						className="mx-auto size-3.5"
						fill="none"
						stroke="currentColor"
						strokeWidth="1.5"
					>
						<path d="M4 4l8 8M12 4l-8 8" />
					</svg>
				</button>
			</header>

			<div className="flex min-h-0 flex-1">
				{/* Left nav — text-only, the session-list mono language,
					    active = bg-accent. */}
				<nav
					aria-label="Settings sections"
					data-testid="settings-nav"
					className="flex w-44 shrink-0 flex-col border-r border-border p-2"
				>
					{SECTIONS.map((s) => (
						<button
							key={s.id}
							type="button"
							data-testid={`settings-nav-${s.id}`}
							aria-current={active === s.id}
							className={`rounded-sm px-3 py-1.5 text-left font-ui text-sm transition-colors ${
								active === s.id
									? "bg-accent text-foreground"
									: "text-muted-foreground hover:bg-accent hover:text-foreground"
							}`}
							onClick={() => setActive(s.id)}
						>
							{s.label}
						</button>
					))}
				</nav>

				{/* Content column — one section at a time, this scrolls. */}
				<div
					className="min-w-0 flex-1 overflow-y-auto"
					data-testid="settings-content"
				>
					{error && (
						<p
							role="alert"
							className="m-4 rounded-sm border border-red-500/40 px-3 py-2 text-xs text-red-500"
							data-testid="settings-error"
						>
							{error}
						</p>
					)}
					{record === undefined ? (
						<p className="px-6 py-5 text-xs text-muted-foreground/70">
							Loading settings…
						</p>
					) : record === null ? (
						<p className="px-6 py-5 text-xs text-muted-foreground/70">
							Settings could not be loaded — refresh to retry.
						</p>
					) : (
						<div>
							{active === "general" && (
								<SettingsSection
									title="General"
									testid="section-general"
								>
									<SettingsRow
										label="Auto-update"
										hint="The update mechanism ships in a later wave"
										testid="row-auto-update"
									>
										<Toggle
											checked={record.general?.autoUpdate ?? true}
											label="auto update"
											onChange={(on) =>
												void write("general", { autoUpdate: on })
											}
										/>
									</SettingsRow>
								</SettingsSection>
							)}
							{active === "agent" && (
								<SettingsSection
									title="Agent"
									testid="section-agent"
								>
									<AgentSection
										agent={record.agent}
										onSectionChange={(next: AgentSettings) =>
											void write("agent", next)
										}
									/>
								</SettingsSection>
							)}
							{active === "appearance" && (
								<SettingsSection
									title="Appearance"
									testid="section-appearance"
								>
									<AppearanceSection
										appearance={record.appearance}
										onSectionChange={(next: AppearanceSettings) =>
											void write("appearance", next)
										}
									/>
								</SettingsSection>
							)}
							{active === "graph" && (
								<SettingsSection
									title="Graph"
									testid="section-graph"
								>
									<GraphSection
										graph={record.graph}
										onSectionChange={(next: GraphSettings) =>
											void write("graph", next)
										}
									/>
								</SettingsSection>
							)}
							{active === "keyboard" && (
								<SettingsSection
									title="Keyboard"
									hint="Stored on this device"
									testid="section-keyboard"
								>
									<KeyboardSection />
								</SettingsSection>
							)}
						</div>
					)}
				</div>
			</div>
		</div>
	);
}