export type PromptItem = {
	text: string;
	timestamp?: number;
};

export function messageText(content: unknown): string {
	if (typeof content === "string") return content.trim();
	if (!Array.isArray(content)) return "";
	return content
		.filter((block): block is { type: string; text: string } => {
			return Boolean(
				block &&
					typeof block === "object" &&
					(block as { type?: unknown }).type === "text" &&
					typeof (block as { text?: unknown }).text === "string",
			);
		})
		.map((block) => block.text)
		.join("\n")
		.trim();
}

export function printableInput(data: string): string | undefined {
	if (!data) return undefined;

	// Plain terminal input, including multi-character paste chunks. Control bytes are rejected.
	if (!data.includes("\x1b")) {
		return [...data].every((ch) => {
			const code = ch.codePointAt(0) ?? 0;
			return code >= 32 && code !== 127;
		})
			? data
			: undefined;
	}

	// Kitty keyboard protocol: CSI codepoint ; modifiers u. Modifiers are 1-indexed.
	const kitty = data.match(/^\x1b\[(\d+)(?:;(\d+)(?::\d+)?)?u$/);
	if (kitty) {
		const codepoint = Number.parseInt(kitty[1]!, 10);
		const modifier = kitty[2] ? Number.parseInt(kitty[2], 10) - 1 : 0;
		// Allow no modifiers or Shift only. Reject Ctrl/Alt/Super so shortcuts are never inserted.
		if ((modifier & ~1) !== 0 || !Number.isFinite(codepoint) || codepoint < 32) return undefined;
		try {
			return String.fromCodePoint(codepoint);
		} catch {
			return undefined;
		}
	}

	// xterm modifyOtherKeys: CSI 27 ; modifiers ; codepoint ~. Modifiers are 1-indexed.
	const modifyOtherKeys = data.match(/^\x1b\[27;(\d+);(\d+)~$/);
	if (modifyOtherKeys) {
		const modifier = Number.parseInt(modifyOtherKeys[1]!, 10) - 1;
		const codepoint = Number.parseInt(modifyOtherKeys[2]!, 10);
		if ((modifier & ~1) !== 0 || !Number.isFinite(codepoint) || codepoint < 32) return undefined;
		try {
			return String.fromCodePoint(codepoint);
		} catch {
			return undefined;
		}
	}

	return undefined;
}

export class ReverseSearchController {
	active = false;
	query = "";
	originalText = "";
	matches: PromptItem[] = [];
	selected = 0;
	statusMessage = "";

	start(prompts: PromptItem[], originalText: string): string {
		this.active = true;
		this.query = "";
		this.originalText = originalText;
		this.matches = this.uniquePrompts(prompts);
		this.selected = 0;
		this.statusMessage = this.matches.length === 0 ? "no prompts" : "type to search";
		return this.originalText;
	}

	accept(): void {
		this.active = false;
		this.statusMessage = "";
	}

	cancel(): string {
		this.active = false;
		this.query = "";
		this.matches = [];
		this.selected = 0;
		this.statusMessage = "";
		return this.originalText;
	}

	appendQuery(text: string): string {
		this.query += text;
		this.selected = 0;
		return this.refreshMatch();
	}

	backspaceQuery(): string {
		if (this.query.length > 0) {
			this.query = [...this.query].slice(0, -1).join("");
			this.selected = 0;
		}
		return this.refreshMatch();
	}

	clearQuery(): string {
		this.query = "";
		this.selected = 0;
		this.statusMessage = this.matches.length === 0 ? "no prompts" : "type to search";
		return this.originalText;
	}

	cycleOlder(): string {
		return this.cycle(1);
	}

	cycleNewer(): string {
		return this.cycle(-1);
	}

	searchLabel(): string {
		const q = this.query.replace(/`/g, "\\`");
		const label = this.statusMessage === "failed" ? "failing-reverse-i-search" : "reverse-i-search";
		return ` ${label}\`${q}': ${this.statusMessage} `;
	}

	private cycle(delta: 1 | -1): string {
		if (!this.query) return this.originalText;
		const filtered = this.filteredMatches();
		if (filtered.length === 0) return this.refreshMatch();
		this.selected = (this.selected + delta + filtered.length) % filtered.length;
		return this.applyMatch(filtered);
	}

	private refreshMatch(): string {
		this.selected = 0;
		if (!this.query) {
			this.statusMessage = this.matches.length === 0 ? "no prompts" : "type to search";
			return this.originalText;
		}
		return this.applyMatch(this.filteredMatches());
	}

	private applyMatch(filtered: PromptItem[]): string {
		if (filtered.length === 0) {
			this.statusMessage = this.matches.length === 0 ? "no prompts" : "failed";
			return this.originalText;
		}

		const match = filtered[this.selected] ?? filtered[0]!;
		this.statusMessage = `${this.selected + 1}/${filtered.length}`;
		return match.text;
	}

	private filteredMatches(): PromptItem[] {
		const q = this.query.toLowerCase();
		if (!q) return [];
		return this.matches.filter((item) => item.text.toLowerCase().includes(q));
	}

	private uniquePrompts(prompts: PromptItem[]): PromptItem[] {
		const seen = new Set<string>();
		const out: PromptItem[] = [];
		for (const prompt of prompts) {
			const text = prompt.text.trim();
			if (!text || seen.has(text)) continue;
			seen.add(text);
			out.push({ ...prompt, text });
		}
		return out;
	}
}