import type { ExtensionAPI, Theme } from "@earendil-works/pi-coding-agent";
import { inspectGate } from "../src/harness/gates.ts";
import { readActiveRun } from "../src/harness/state.ts";
import type { ActiveRun, GateResult } from "../src/harness/types.ts";
import { phaseOrderForRun } from "../src/harness/types.ts";
import { formatProductProfile } from "../src/product/profile.ts";

/** ANSI escape sequence pattern: CSI, OSC, APC. */
const ANSI_RE = /\x1b\[[0-9;]*[A-Za-z]|\x1b\][^\x07]*\x07|\x1b_[^\x1b]*\x1b\\/g;

/** Visible width of a string (strips ANSI codes; CJK/wide chars = 2 columns). */
function visibleWidth(str: string): number {
	let width = 0;
	const clean = str.replace(ANSI_RE, "");
	for (const ch of clean) {
		const code = ch.codePointAt(0)!;
		width +=
			code >= 0x1100 &&
			!(code >= 0x00a0 && code <= 0x00ff) &&
			((code >= 0x1100 && code <= 0x115f) ||
				(code >= 0x2329 && code <= 0x232a) ||
				(code >= 0x2e80 && code <= 0x303e) ||
				(code >= 0x3040 && code <= 0x3247) ||
				(code >= 0x3250 && code <= 0x4dbf) ||
				(code >= 0x4e00 && code <= 0xa4c6) ||
				(code >= 0xa960 && code <= 0xa97c) ||
				(code >= 0xac00 && code <= 0xd7a3) ||
				(code >= 0xf900 && code <= 0xfaff) ||
				(code >= 0xfe10 && code <= 0xfe19) ||
				(code >= 0xfe30 && code <= 0xfe6b) ||
				(code >= 0xff01 && code <= 0xff60) ||
				(code >= 0xffe0 && code <= 0xffe6) ||
				(code >= 0x1f300 && code <= 0x1f9ff) ||
				(code >= 0x20000 && code <= 0x2fffd))
				? 2
				: 1;
	}
	return width;
}

/**
 * If the line's visible width exceeds `maxWidth`, truncate visible characters
 * and append `>` so the result fits. Preserves ANSI codes in the kept portion
 * and appends SGR reset before the `>`. No padding — pi-tui only requires
 * visibleWidth <= width.
 */
export function clipLine(text: string, maxWidth: number): string {
	if (maxWidth <= 0) return "";
	const vw = visibleWidth(text);
	if (vw <= maxWidth) return text;

	const targetW = maxWidth - 1; // reserve 1 col for ">"
	let result = "";
	let visibleSoFar = 0;
	let i = 0;

	while (i < text.length && visibleSoFar < targetW) {
		// Preserve ANSI escape sequences
		if (text[i] === "\x1b") {
			const m = text.slice(i).match(/^\x1b(?:\[[0-9;]*[A-Za-z]|\][^\x07]*\x07|_[^\x1b]*\x1b\\)/);
			if (m) {
				result += m[0];
				i += m[0].length;
				continue;
			}
		}

		const ch = text[i];
		const code = ch.codePointAt(0)!;
		const wide =
			(code >= 0x1100 && code <= 0x115f) ||
			(code >= 0x2329 && code <= 0x232a) ||
			(code >= 0x2e80 && code <= 0x303e) ||
			(code >= 0x3040 && code <= 0x3247) ||
			(code >= 0x3250 && code <= 0x4dbf) ||
			(code >= 0x4e00 && code <= 0xa4c6) ||
			(code >= 0xa960 && code <= 0xa97c) ||
			(code >= 0xac00 && code <= 0xd7a3) ||
			(code >= 0xf900 && code <= 0xfaff) ||
			(code >= 0xfe10 && code <= 0xfe19) ||
			(code >= 0xfe30 && code <= 0xfe6b) ||
			(code >= 0xff01 && code <= 0xff60) ||
			(code >= 0xffe0 && code <= 0xffe6) ||
			(code >= 0x1f300 && code <= 0x1f9ff) ||
			(code >= 0x20000 && code <= 0x2fffd);
		const charW = wide ? 2 : 1;

		if (visibleSoFar + charW > targetW) break;

		result += ch;
		visibleSoFar += charW;
		i++;
	}

	return result + "\x1b[0m>";
}

function formatProduct(run: ActiveRun | undefined): string {
	if (!run) return "未选择";
	if (run.profile?.product === "unknown") return "未确认";
	return formatProductProfile(run.profile);
}

function formatPhase(phase: ActiveRun["phase"] | undefined): string {
	return phase ?? "空闲";
}

function formatGate(gate: GateResult | undefined): string {
	if (!gate) return "门禁：待检查";
	return gate.passed ? "门禁：通过" : "门禁：阻塞";
}

function safeInspectGate(cwd: string, run: ActiveRun | undefined): GateResult | undefined {
	if (!run) return undefined;
	try {
		return inspectGate(cwd, run);
	} catch (error) {
		return {
			passed: false,
			reason: error instanceof Error ? error.message : String(error),
			checkedAt: new Date().toISOString(),
		};
	}
}

function riskLevel(run: ActiveRun | undefined): string {
	return run?.riskAssessment?.level ?? "未知";
}

function riskColor(risk: string): "error" | "warning" | "muted" | "success" {
	if (risk === "high") return "error";
	if (risk === "medium") return "warning";
	if (risk === "未知") return "muted";
	return "success";
}

function logoLines(theme: Theme): string[] {
	const accent = (text: string) => theme.fg("accent", text);
	const muted = (text: string) => theme.fg("muted", text);

	return [
		`${accent("KCode")} ${muted("金蝶 Pi Harness")}`,
		`${accent("=====")} ${muted("lite | standard | strict")}`,
	];
}

export default function (pi: ExtensionAPI) {
	pi.on("session_start", async (_event, ctx) => {
		if (ctx.mode !== "tui") return;

		ctx.ui.setHeader((_tui, theme) => {
			return {
				render(width: number): string[] {
					const run = readActiveRun(ctx.cwd);
					const gateState = safeInspectGate(ctx.cwd, run);
					const phase = formatPhase(run?.phase);
					const product = formatProduct(run);
					const gate = formatGate(gateState);
					const risk = riskLevel(run);
					const runId = run?.id ?? "无";
					const mode = run?.mode ?? "未启动";
					const order = run ? phaseOrderForRun(run).join(" -> ") : "未启动";

					const status = [
						theme.fg("muted", "阶段："),
						theme.fg("accent", phase),
						theme.fg("muted", " | 模式："),
						theme.fg("text", mode),
						theme.fg("muted", " | 产品："),
						theme.fg("text", product),
						theme.fg("muted", " | 风险："),
						theme.fg(riskColor(risk), risk),
						theme.fg("muted", " | "),
						theme.fg(gateState?.passed === false ? "error" : "muted", gate),
					].join("");

					return [
						"",
						...logoLines(theme).map((line) => clipLine(line, width)),
						clipLine(status, width),
						clipLine(theme.fg("dim", `流程：${order}`), width),
						clipLine(theme.fg("dim", `run：${runId}`), width),
						"",
					];
				},
				invalidate() {},
			};
		});
	});

	pi.registerCommand("kcode-header", {
		description: "恢复 KCode 金蝶标题栏",
		handler: async (_args, ctx) => {
			if (ctx.mode !== "tui") return;
			ctx.ui.notify("重启会话或重新加载扩展以恢复 KCode 标题栏。", "info");
		},
	});

	pi.registerCommand("builtin-header", {
		description: "恢复 Pi 内置标题栏",
		handler: async (_args, ctx) => {
			if (ctx.mode !== "tui") return;
			ctx.ui.setHeader(undefined);
			ctx.ui.notify("已恢复 Pi 内置标题栏", "info");
		},
	});
}