import type { ExtensionAPI, ExtensionCommandContext } from "@earendil-works/pi-coding-agent";
import { fmt } from "./format";
import { fileRows, skillRows, toolRows } from "./lists";
import { buildReport } from "./report";
import type { ListRow } from "./types";
import { showListUi, showPanel } from "./ui";

/**
 * The `/context` command handler — routes subcommands and picks the output
 * sink per mode (tui / json / print / notify). Factory form so `index.ts`
 * stays a thin registration stub.
 */
export const contextCommand =
	(pi: ExtensionAPI) =>
	async (args: string | undefined, ctx: ExtensionCommandContext): Promise<void> => {
		const sub = (args ?? "").trim().split(/\s+/)[0]?.toLowerCase() ?? "";

		/* --- list subcommands (skills / tools / files) --- */
		if (sub === "skills" || sub === "tools" || sub === "files") {
			const rows: ListRow[] =
				sub === "skills"
					? skillRows(ctx)
					: sub === "tools"
						? toolRows(pi)
						: fileRows(ctx);
			const title =
				sub === "skills" ? "Skills" : sub === "tools" ? "Tools" : "Context files";

			if (ctx.mode === "tui") {
				await showListUi(ctx, title, rows);
				return;
			}

			// Non-TUI fallback: plain text rows.
			const text = rows
				.sort((a, b) => b.tokens - a.tokens)
				.map((r) => `${r.name}\t${r.desc}\t${fmt(r.tokens)}`)
				.join("\n");
			const payload = `${title}:\n${text || "(none)"}`;
			if (ctx.hasUI) ctx.ui.notify(payload, "info");
			else if (ctx.mode === "json") process.stderr.write(payload + "\n");
			else console.log(payload);
			return;
		}

		if (sub === "help" || sub === "h") {
			const help =
				"Context usage commands:\n" +
				"  /context           overview + section breakdown\n" +
				"  /context skills    list loaded skills by estimated size\n" +
				"  /context tools     list registered tools by estimated size\n" +
				"  /context files     list loaded context files (AGENTS.md etc.)";
			if (ctx.mode === "tui") await showPanel(ctx, help);
			else console.log(help);
			return;
		}

		/* --- default: overview + breakdown --- */
		if (ctx.mode === "tui") {
			await showPanel(ctx, buildReport(pi, ctx));
			return;
		}

		const report = buildReport(pi, ctx);
		if (ctx.hasUI) {
			ctx.ui.notify(report, "info");
		} else if (ctx.mode === "json") {
			// JSON mode streams events to stdout — keep the report off the protocol.
			process.stderr.write(report + "\n");
		} else {
			// Print mode: emit the report as plain text.
			console.log(report);
		}
	};