import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";
import {
	MinimalEditor,
	editorConfig,
	getEditorRef,
	setContextStats,
	updateGitInfo,
	ContextStats,
} from "./MinimalEditor";
import { createEmptyFooter } from "./FooterManager";
import type { AgentEndEvent } from "@mariozechner/pi-coding-agent";
import type { ExtensionEvent } from "@mariozechner/pi-coding-agent";
import * as fs from "node:fs";
import * as path from "node:path";
import * as os from "node:os";

/** Help text for /prompt-prefix command */
const PROMPT_HELP = `%d=dir %D=path %cf%=ctx% %gb%=branch %gs%=git %td%=time %%=%`;

/** Config file path */
const CONFIG_DIR = path.join(os.homedir(), ".config", "pi-ui-minimal");
const CONFIG_FILE = path.join(CONFIG_DIR, "config.json");

interface Config {
	prefix: string;
}

/** Load config from file */
function loadConfig(): Config {
	try {
		if (fs.existsSync(CONFIG_FILE)) {
			const data = fs.readFileSync(CONFIG_FILE, "utf-8");
			const config = JSON.parse(data) as Config;
			if (config.prefix) {
				return config;
			}
		}
	} catch {
		// Ignore errors, use defaults
	}
	return { prefix: "%d > " };
}

/** Save config to file */
function saveConfig(config: Config): void {
	try {
		fs.mkdirSync(CONFIG_DIR, { recursive: true });
		fs.writeFileSync(CONFIG_FILE, JSON.stringify(config, null, 2), "utf-8");
	} catch {
		// Ignore write errors
	}
}

/** Hides default footer, removes editor borders, adds bold CWD prompt. */
export default function minimalFooter(pi: ExtensionAPI) {
	pi.on("session_start", (_event, ctx) => {
		// Hide default footer
		ctx.ui.setFooter(() => createEmptyFooter());

		// Set custom editor component
		ctx.ui.setEditorComponent((tui, theme, keybindings) => new MinimalEditor(tui, theme as any, keybindings));

		// Update cwd in config
		editorConfig.cwd = ctx.cwd;

		// Update git info on session start
		updateGitInfo();

		// Load saved config (lowest priority)
		const savedConfig = loadConfig();

		// PI_PS1 env var overrides saved config
		const ps1 = process.env.PI_PS1;
		if (ps1?.trim()) {
			editorConfig.prefix = ps1.trimStart();
		} else {
			editorConfig.prefix = savedConfig.prefix;
		}

		// Subscribe to message_end events to update context fill percentage
		pi.on("message_end", (_evt: ExtensionEvent, ctx) => {
			const usage = ctx.getContextUsage();
			if (usage && usage.percent !== null) {
				setContextStats({
					tokens: usage.tokens ?? 0,
					contextWindow: usage.contextWindow,
					percent: Math.round(usage.percent),
				});
				getEditorRef()?.invalidate();
			}
		});

		// Parse prompt argument: strip outer quotes if present, preserve internal spaces
		function parsePromptArg(input: string | undefined): string | null {
			if (!input) return null;
			// Strip outer matching quotes (single or double)
			const trimmed = input.trim();
			if (
				trimmed.length >= 2 &&
				((trimmed.startsWith('"') && trimmed.endsWith('"')) ||
					(trimmed.startsWith("'") && trimmed.endsWith("'")))
			) {
				return trimmed.slice(1, -1);
			}
			return input; // Return original with spaces preserved
		}

		// Register /prompt-prefix command
		pi.registerCommand("prompt-prefix", {
			description: `Set prompt prefix (${PROMPT_HELP})`,
			handler: async (args, _ctx) => {
				const prefix = parsePromptArg(args);
				if (prefix !== null) {
					editorConfig.prefix = prefix;
					saveConfig({ prefix: editorConfig.prefix });
					_ctx.ui.notify(`Prompt set: "${editorConfig.prefix}"`, "info");
					getEditorRef()?.invalidate();
				} else {
					_ctx.ui.notify(`Prompt: "${editorConfig.prefix}"\n${PROMPT_HELP}`, "info");
				}
			},
		});
	});
}

// Re-export for consumers
export {
	MinimalEditor,
	editorConfig,
	setContextStats,
	getContextStats,
	setGitInfo,
	getGitInfo,
	updateGitInfo,
	ContextStats,
	GitInfo,
} from "./MinimalEditor";
export { createEmptyFooter, hideFooter } from "./FooterManager";