/**
 * Settings list component with support for cycling values and string input.
 * Based on @earendil-works/pi-tui SettingsList, extended with string editing.
 */

import {
	type Component,
	fuzzyFilter,
	getKeybindings,
	Input,
	matchesKey,
	truncateToWidth,
	visibleWidth,
	wrapTextWithAnsi,
} from "@earendil-works/pi-tui";

export interface SettingItem {
	/** Unique identifier for this setting */
	id: string;
	/** Display label (left side) */
	label: string;
	/** Optional description shown when selected */
	description?: string;
	/** Current value to display (right side) */
	currentValue: string;
	/**
	 * If provided, Enter/Space cycles through these values.
	 * If undefined/empty, the setting is treated as a string input.
	 */
	values?: string[];
	/** If provided, Enter opens this submenu. Receives current value and done callback. */
	submenu?: (currentValue: string, done: (selectedValue?: string) => void) => Component;
	/** If false, item is selectable but cannot be edited or changed. */
	editable?: boolean;
}

export interface SettingsListTheme {
	label: (text: string, selected: boolean) => string;
	value: (text: string, selected: boolean) => string;
	description: (text: string) => string;
	cursor: string;
	hint: (text: string) => string;
}

export interface SettingsListOptions {
	enableSearch?: boolean;
}

export class SettingsList implements Component {
	private items: SettingItem[];
	private filteredItems: SettingItem[];
	private theme: SettingsListTheme;
	private selectedIndex = 0;
	private maxVisible: number;
	private onChange: (id: string, newValue: string) => void;
	private onCancel: () => void;
	private searchInput?: Input;
	private searchEnabled: boolean;

	// Submenu state
	private submenuComponent: Component | null = null;
	private submenuItemIndex: number | null = null;

	// String editing state
	private editingInput: Input | null = null;
	private editingItemIndex: number | null = null;

	constructor(
		items: SettingItem[],
		maxVisible: number,
		theme: SettingsListTheme,
		onChange: (id: string, newValue: string) => void,
		onCancel: () => void,
		options: SettingsListOptions = {},
	) {
		this.items = items;
		this.filteredItems = items;
		this.maxVisible = maxVisible;
		this.theme = theme;
		this.onChange = onChange;
		this.onCancel = onCancel;
		this.searchEnabled = options.enableSearch ?? false;
		if (this.searchEnabled) {
			this.searchInput = new Input();
		}
	}

	/** Update an item's currentValue */
	updateValue(id: string, newValue: string): void {
		const item = this.items.find((i) => i.id === id);
		if (item) {
			item.currentValue = newValue;
		}
	}

	invalidate(): void {
		this.submenuComponent?.invalidate?.();
	}

	render(width: number): string[] {
		// If submenu is active, render it instead
		if (this.submenuComponent) {
			return this.submenuComponent.render(width);
		}

		return this.renderMainList(width);
	}

	private renderMainList(width: number): string[] {
		const lines: string[] = [];

		if (this.searchEnabled && this.searchInput && !this.editingInput) {
			lines.push(...this.searchInput.render(width));
			lines.push("");
		}

		if (this.items.length === 0) {
			lines.push(this.theme.hint("  No settings available"));
			if (this.searchEnabled) {
				this.addHintLine(lines);
			}
			return lines;
		}

		const displayItems = this.searchEnabled ? this.filteredItems : this.items;
		if (displayItems.length === 0) {
			lines.push(this.theme.hint("  No matching settings"));
			this.addHintLine(lines);
			return lines;
		}

		// Calculate visible range with scrolling
		const startIndex = Math.max(
			0,
			Math.min(this.selectedIndex - Math.floor(this.maxVisible / 2), displayItems.length - this.maxVisible),
		);
		const endIndex = Math.min(startIndex + this.maxVisible, displayItems.length);

		// Calculate max label width for alignment
		const maxLabelWidth = Math.min(30, Math.max(...this.items.map((item) => visibleWidth(item.label))));

		// Render visible items
		for (let i = startIndex; i < endIndex; i++) {
			const item = displayItems[i];
			if (!item) continue;

			const isSelected = i === this.selectedIndex;
			const isEditing = this.editingInput && this.editingItemIndex === i;
			const prefix = isSelected ? this.theme.cursor : "  ";
			const prefixWidth = visibleWidth(prefix);

			// Pad label to align values
			const labelPadded = item.label + " ".repeat(Math.max(0, maxLabelWidth - visibleWidth(item.label)));
			const labelText = this.theme.label(labelPadded, isSelected);

			// Calculate space for value
			const separator = "  ";
			const usedWidth = prefixWidth + maxLabelWidth + visibleWidth(separator);
			const valueMaxWidth = width - usedWidth - 2;

			if (isEditing && this.editingInput) {
				// Render inline input for string editing
				const inputLines = this.editingInput.render(valueMaxWidth);
				const inputLine = inputLines[0] ?? "";
				lines.push(prefix + labelText + separator + inputLine);
			} else {
				const valueText = this.theme.value(truncateToWidth(item.currentValue, valueMaxWidth, ""), isSelected);
				lines.push(prefix + labelText + separator + valueText);
			}
		}

		// Add scroll indicator if needed
		if (startIndex > 0 || endIndex < displayItems.length) {
			const scrollText = `  (${this.selectedIndex + 1}/${displayItems.length})`;
			lines.push(this.theme.hint(truncateToWidth(scrollText, width - 2, "")));
		}

		// Add description for selected item
		const selectedItem = displayItems[this.selectedIndex];
		if (selectedItem?.description && !this.editingInput) {
			lines.push("");
			const wrappedDesc = wrapTextWithAnsi(selectedItem.description, width - 4);
			for (const line of wrappedDesc) {
				lines.push(this.theme.description(`  ${line}`));
			}
		}

		// Add hint
		this.addHintLine(lines);

		return lines;
	}

	handleInput(data: string): void {
		// If editing a string value, handle input for the editor
		if (this.editingInput) {
			this.handleEditingInput(data);
			return;
		}

		// If submenu is active, delegate all input to it
		if (this.submenuComponent) {
			this.submenuComponent.handleInput?.(data);
			return;
		}

		// Main list input handling
		const kb = getKeybindings();
		const displayItems = this.searchEnabled ? this.filteredItems : this.items;

		if (kb.matches(data, "tui.select.up")) {
			if (displayItems.length === 0) return;
			this.selectedIndex = this.selectedIndex === 0 ? displayItems.length - 1 : this.selectedIndex - 1;
		} else if (kb.matches(data, "tui.select.down")) {
			if (displayItems.length === 0) return;
			this.selectedIndex = this.selectedIndex === displayItems.length - 1 ? 0 : this.selectedIndex + 1;
		} else if (kb.matches(data, "tui.select.confirm") || data === " ") {
			this.activateItem();
		} else if (kb.matches(data, "tui.select.cancel")) {
			this.onCancel();
		} else if (this.searchEnabled && this.searchInput) {
			const sanitized = data.replace(/ /g, "");
			if (!sanitized) {
				return;
			}
			this.searchInput.handleInput(sanitized);
			this.applyFilter(this.searchInput.getValue());
		}
	}

	private handleEditingInput(data: string): void {
		if (!this.editingInput) return;

		// Enter: confirm edit
		if (matchesKey(data, "enter")) {
			this.confirmEdit();
			return;
		}

		// Escape: cancel edit
		if (matchesKey(data, "escape")) {
			this.cancelEdit();
			return;
		}

		// Pass other input to the editor
		this.editingInput.handleInput(data);
	}

	private confirmEdit(): void {
		if (!this.editingInput || this.editingItemIndex === null) return;

		const displayItems = this.searchEnabled ? this.filteredItems : this.items;
		const item = displayItems[this.editingItemIndex];
		if (item) {
			const newValue = this.editingInput.getValue();
			item.currentValue = newValue;
			this.onChange(item.id, newValue);
		}

		this.editingInput = null;
		this.editingItemIndex = null;
	}

	private cancelEdit(): void {
		this.editingInput = null;
		this.editingItemIndex = null;
	}

	private activateItem(): void {
		const displayItems = this.searchEnabled ? this.filteredItems : this.items;
		const item = displayItems[this.selectedIndex];
		if (!item) return;

		if (item.editable === false) {
			return;
		}

		if (item.submenu) {
			// Open submenu, passing current value so it can pre-select correctly
			this.submenuItemIndex = this.selectedIndex;
			this.submenuComponent = item.submenu(item.currentValue, (selectedValue?: string) => {
				if (selectedValue !== undefined) {
					item.currentValue = selectedValue;
					this.onChange(item.id, selectedValue);
				}
				this.closeSubmenu();
			});
		} else if (item.values && item.values.length > 0) {
			// Cycle through values
			const currentIndex = item.values.indexOf(item.currentValue);
			const nextIndex = (currentIndex + 1) % item.values.length;
			const newValue = item.values[nextIndex];
			item.currentValue = newValue;
			this.onChange(item.id, newValue);
		} else {
			// String input - start editing
			this.editingItemIndex = this.selectedIndex;
			this.editingInput = new Input();
			this.editingInput.setValue(item.currentValue);
		}
	}

	private closeSubmenu(): void {
		this.submenuComponent = null;
		// Restore selection to the item that opened the submenu
		if (this.submenuItemIndex !== null) {
			this.selectedIndex = this.submenuItemIndex;
			this.submenuItemIndex = null;
		}
	}

	private applyFilter(query: string): void {
		this.filteredItems = fuzzyFilter(this.items, query, (item) => item.label);
		this.selectedIndex = 0;
	}

	private addHintLine(lines: string[]): void {
		lines.push("");
		if (this.editingInput) {
			lines.push(this.theme.hint("  Enter to confirm · Esc to cancel"));
		} else if (this.searchEnabled) {
			lines.push(this.theme.hint("  Type to search · Enter/Space to change · Esc to cancel"));
		} else {
			lines.push(this.theme.hint("  Enter/Space to change · Esc to cancel"));
		}
	}
}