import { Key, matchesKey, truncateToWidth } from "@mariozechner/pi-tui";
import type { CommandContext, ProbeItem, SelectItem } from "../types.ts";

function normalizeSelectItems(items: Array<string | SelectItem>): SelectItem[] {
	return items.map((item) => (typeof item === "string" ? { value: item, label: item } : item));
}

export async function selectOne(
	ctx: CommandContext,
	title: string,
	items: Array<string | SelectItem>,
	options?: { initialIndex?: number },
): Promise<string | null> {
	const normalizedItems = normalizeSelectItems(items);
	if (normalizedItems.length === 0) return null;

	return await ctx.ui.custom<string | null>((tui, theme, _kb, done) => {
		let cursor = Math.max(0, Math.min(options?.initialIndex ?? 0, normalizedItems.length - 1));
		let query = "";
		let cachedLines: string[] | undefined;
		const maxVisible = 12;

		function getVisibleItems() {
			const lowerQuery = query.trim().toLowerCase();
			if (!lowerQuery) return normalizedItems;
			return normalizedItems.filter((item) => {
				const haystack = `${item.label} ${item.suffix ?? ""} ${item.description ?? ""} ${item.searchText ?? ""}`.toLowerCase();
				return haystack.includes(lowerQuery);
			});
		}

		function refresh() {
			const visibleItems = getVisibleItems();
			if (visibleItems.length === 0) cursor = 0;
			else if (cursor >= visibleItems.length) cursor = visibleItems.length - 1;
			cachedLines = undefined;
			tui.requestRender();
		}

		return {
			render(width: number) {
				if (cachedLines) return cachedLines;

				const visibleItems = getVisibleItems();
				const safeWidth = Math.max(10, width);
				const lines: string[] = [];
				const add = (line = "") => lines.push(truncateToWidth(line, safeWidth));
				const border = theme.fg("accent", "─".repeat(safeWidth));

				add(border);
				add(` ${theme.fg("accent", theme.bold(title))}`);
				add(` ${theme.fg("text", `Search: ${query || "-"}`)}`);
				add();

				if (visibleItems.length === 0) {
					add(theme.fg("warning", " No matches."));
				} else {
					const start = Math.max(0, Math.min(cursor - Math.floor(maxVisible / 2), Math.max(0, visibleItems.length - maxVisible)));
					const end = Math.min(visibleItems.length, start + maxVisible);

					for (let i = start; i < end; i++) {
						const item = visibleItems[i];
						const active = i === cursor;
						const prefix = active ? theme.fg("accent", "> ") : "  ";
						const label = active ? theme.fg("accent", item.label) : theme.fg("text", item.label);
						const suffix = item.suffix ? theme.fg("dim", item.suffix) : "";
						add(`${prefix}${label}${suffix}`);
						if (item.description) {
							for (const line of item.description.split("\n")) {
								add(`   ${theme.fg("muted", line)}`);
							}
						}
					}

					if (visibleItems.length > maxVisible) {
						add();
						add(theme.fg("dim", ` ${start + 1}-${end} of ${visibleItems.length}`));
					}
				}

				add();
				add(theme.fg("dim", " Type to search • ↑↓ move (wraps) • enter confirm • backspace delete • esc cancel"));
				add(border);

				cachedLines = lines;
				return lines;
			},
			invalidate() {
				cachedLines = undefined;
			},
			handleInput(data: string) {
				const visibleItems = getVisibleItems();
				if (matchesKey(data, Key.up)) {
					if (visibleItems.length === 0) return;
					cursor = cursor === 0 ? visibleItems.length - 1 : cursor - 1;
					refresh();
					return;
				}
				if (matchesKey(data, Key.down)) {
					if (visibleItems.length === 0) return;
					cursor = cursor === visibleItems.length - 1 ? 0 : cursor + 1;
					refresh();
					return;
				}
				if (matchesKey(data, Key.enter)) {
					const item = visibleItems[cursor];
					done(item?.value ?? null);
					return;
				}
				if (matchesKey(data, Key.escape)) {
					done(null);
					return;
				}
				if (data === "\u007f" || data === "\b") {
					if (query.length > 0) {
						query = query.slice(0, -1);
						refresh();
					}
					return;
				}
				if (data >= " " && data !== "\u001b" && data !== "\r" && data !== "\n") {
					query += data;
					cursor = 0;
					refresh();
				}
			},
		};
	});
}

// Tri-state multi-select: each item cycles through its own allowed states on
// space. "[ ]" off, "[-]" mid, "[x]" on — the caller decides what each state
// means per item (e.g. skip/remove, keep-without-update, add/update).
export type TriState = "off" | "mid" | "on";
export type TriItem = {
	value: string;
	label: string;
	description?: string;
	searchText?: string;
	// States this item cycles through, in toggle order.
	states: TriState[];
	initial: TriState;
};

export async function pickTriState(
	ctx: CommandContext,
	title: string,
	items: TriItem[],
	legend = "[ ] remove/skip • [-] keep without update • [x] keep/add with latest metadata",
): Promise<Map<string, TriState> | null> {
	if (items.length === 0) return new Map();
	return await ctx.ui.custom<Map<string, TriState> | null>((tui, theme, _kb, done) => {
		let cursor = 0;
		let query = "";
		const state = new Map<string, TriState>(items.map((item) => [item.value, item.initial]));
		let cachedLines: string[] | undefined;
		const maxVisible = 12;

		function getVisibleItems() {
			const lowerQuery = query.trim().toLowerCase();
			if (!lowerQuery) return items;
			return items.filter((item) => {
				const haystack = `${item.label} ${item.value} ${item.description ?? ""} ${item.searchText ?? ""}`.toLowerCase();
				return haystack.includes(lowerQuery);
			});
		}

		function refresh() {
			const visibleItems = getVisibleItems();
			if (visibleItems.length === 0) cursor = 0;
			else if (cursor >= visibleItems.length) cursor = visibleItems.length - 1;
			cachedLines = undefined;
			tui.requestRender();
		}

		function box(s: TriState): string {
			if (s === "on") return theme.fg("success", "[x]");
			if (s === "mid") return theme.fg("warning", "[-]");
			return theme.fg("muted", "[ ]");
		}

		return {
			render(width: number) {
				if (cachedLines) return cachedLines;

				const visibleItems = getVisibleItems();
				const safeWidth = Math.max(10, width);
				const lines: string[] = [];
				const add = (line = "") => lines.push(truncateToWidth(line, safeWidth));
				const border = theme.fg("accent", "─".repeat(safeWidth));

				add(border);
				add(` ${theme.fg("accent", theme.bold(title))}`);
				add(` ${theme.fg("text", `Search: ${query || "-"}`)}`);
				add(` ${theme.fg("muted", `${items.length} models`)}`);
				add();

				if (visibleItems.length === 0) {
					add(theme.fg("warning", " No matching models."));
				} else {
					const start = Math.max(0, Math.min(cursor - Math.floor(maxVisible / 2), Math.max(0, visibleItems.length - maxVisible)));
					const end = Math.min(visibleItems.length, start + maxVisible);

					for (let i = start; i < end; i++) {
						const item = visibleItems[i];
						const active = i === cursor;
						const prefix = active ? theme.fg("accent", "> ") : "  ";
						const label = active ? theme.fg("accent", item.label) : theme.fg("text", item.label);
						const desc = item.description ? ` ${theme.fg("muted", item.description.replace(/\s*\n\s*/g, " "))}` : "";
						add(`${prefix}${box(state.get(item.value) ?? item.initial)} ${label}${desc}`);
					}

					if (visibleItems.length > maxVisible) {
						add();
						add(theme.fg("dim", ` ${start + 1}-${end} of ${visibleItems.length}`));
					}
				}

				add();
				add(theme.fg("dim", " Type to search • ↑↓ move (wraps) • space toggle • enter confirm • backspace delete • esc cancel"));
				add(theme.fg("dim", ` ${legend}`));
				add(border);

				cachedLines = lines;
				return lines;
			},
			invalidate() {
				cachedLines = undefined;
			},
			handleInput(data: string) {
				const visibleItems = getVisibleItems();
				if (matchesKey(data, Key.up)) {
					if (visibleItems.length === 0) return;
					cursor = cursor === 0 ? visibleItems.length - 1 : cursor - 1;
					refresh();
					return;
				}
				if (matchesKey(data, Key.down)) {
					if (visibleItems.length === 0) return;
					cursor = cursor === visibleItems.length - 1 ? 0 : cursor + 1;
					refresh();
					return;
				}
				if (data === " ") {
					const item = visibleItems[cursor];
					if (!item) return;
					const current = state.get(item.value) ?? item.initial;
					const index = item.states.indexOf(current);
					state.set(item.value, item.states[(index + 1) % item.states.length]);
					refresh();
					return;
				}
				if (matchesKey(data, Key.enter)) {
					done(new Map(state));
					return;
				}
				if (matchesKey(data, Key.escape)) {
					done(null);
					return;
				}
				if (data === "007f" || data === "\b") {
					if (query.length > 0) {
						query = query.slice(0, -1);
						refresh();
					}
					return;
				}
				if (data >= " " && data !== "001b" && data !== "\r" && data !== "\n") {
					query += data;
					cursor = 0;
					refresh();
				}
			},
		};
	});
}

export async function pickMany(
	ctx: CommandContext,
	title: string,
	items: ProbeItem[],
): Promise<string[] | null> {
	return await ctx.ui.custom<string[] | null>((tui, theme, _kb, done) => {
		let cursor = 0;
		let query = "";
		const selected = new Set<string>();
		let cachedLines: string[] | undefined;
		const maxVisible = 12;

		function getVisibleItems() {
			const lowerQuery = query.trim().toLowerCase();
			if (!lowerQuery) return items;
			return items.filter((item) => {
				const haystack = `${item.label} ${item.value} ${item.description ?? ""}`.toLowerCase();
				return haystack.includes(lowerQuery);
			});
		}

		function refresh() {
			const visibleItems = getVisibleItems();
			if (visibleItems.length === 0) cursor = 0;
			else if (cursor >= visibleItems.length) cursor = visibleItems.length - 1;
			cachedLines = undefined;
			tui.requestRender();
		}

		return {
			render(width: number) {
				if (cachedLines) return cachedLines;

				const visibleItems = getVisibleItems();
				const safeWidth = Math.max(10, width);
				const lines: string[] = [];
				const add = (line = "") => lines.push(truncateToWidth(line, safeWidth));
				const border = theme.fg("accent", "─".repeat(safeWidth));

				add(border);
				add(` ${theme.fg("accent", theme.bold(title))}`);
				add(` ${theme.fg("text", `Search: ${query || "-"}`)}`);
				add(` ${theme.fg("muted", `${selected.size} selected • ${visibleItems.length}/${items.length} shown`)}`);
				add();

				if (visibleItems.length === 0) {
					add(theme.fg("warning", " No matching models."));
				} else {
					const start = Math.max(0, Math.min(cursor - Math.floor(maxVisible / 2), Math.max(0, visibleItems.length - maxVisible)));
					const end = Math.min(visibleItems.length, start + maxVisible);

					for (let i = start; i < end; i++) {
						const item = visibleItems[i];
						const active = i === cursor;
						const checked = selected.has(item.value);
						const prefix = active ? theme.fg("accent", "> ") : "  ";
						const box = checked ? theme.fg("success", "[x]") : theme.fg("muted", "[ ]");
						const label = active ? theme.fg("accent", item.label) : theme.fg("text", item.label);
						const desc = item.description ? ` ${theme.fg("muted", item.description.replace(/\s*\n\s*/g, " "))}` : "";
						add(`${prefix}${box} ${label}${desc}`);
					}

					if (visibleItems.length > maxVisible) {
						add();
						add(theme.fg("dim", ` ${start + 1}-${end} of ${visibleItems.length}`));
					}
				}

				add();
				add(theme.fg("dim", " Type to search • ↑↓ move (wraps) • space toggle • enter confirm • backspace delete • esc cancel"));
				if (selected.size === 0) {
					add(theme.fg("warning", " Select at least one model before confirming."));
				}
				add(border);

				cachedLines = lines;
				return lines;
			},
			invalidate() {
				cachedLines = undefined;
			},
			handleInput(data: string) {
				const visibleItems = getVisibleItems();
				if (matchesKey(data, Key.up)) {
					if (visibleItems.length === 0) return;
					cursor = cursor === 0 ? visibleItems.length - 1 : cursor - 1;
					refresh();
					return;
				}
				if (matchesKey(data, Key.down)) {
					if (visibleItems.length === 0) return;
					cursor = cursor === visibleItems.length - 1 ? 0 : cursor + 1;
					refresh();
					return;
				}
				if (data === " ") {
					const value = visibleItems[cursor]?.value;
					if (!value) return;
					if (selected.has(value)) selected.delete(value);
					else selected.add(value);
					refresh();
					return;
				}
				if (matchesKey(data, Key.enter)) {
					if (selected.size > 0) done(Array.from(selected));
					return;
				}
				if (matchesKey(data, Key.escape)) {
					done(null);
					return;
				}
				if (data === "\u007f" || data === "\b") {
					if (query.length > 0) {
						query = query.slice(0, -1);
						refresh();
					}
					return;
				}
				if (data >= " " && data !== "\u001b" && data !== "\r" && data !== "\n") {
					query += data;
					cursor = 0;
					refresh();
				}
			},
		};
	});
}