import { existsSync, readdirSync, statSync } from "node:fs";
import { join } from "node:path";
import type { ActiveRun } from "./types.ts";
import { runRoot } from "./paths.ts";

export type MetadataDiscoveryKind = "evidence" | "project-file" | "mcp-config" | "official-config";

export interface MetadataDiscoveryItem {
	kind: MetadataDiscoveryKind;
	path: string;
	action: string;
}

export interface MetadataDiscoveryResult {
	items: MetadataDiscoveryItem[];
	recommendedAction: string;
}

const METADATA_FILE_PATTERN = /(fkernelxml|fdata|metadata|entitydesign|meta)[^\\/]*\.(xml|json|txt)$/i;
const IGNORED_DIRS = new Set([".git", ".pi", ".codex", ".agents", "node_modules", "dist", "vendor", ".tmp"]);

export function discoverMetadataSources(cwd: string, run: ActiveRun): MetadataDiscoveryResult {
	const items: MetadataDiscoveryItem[] = [];
	const root = runRoot(cwd, run);

	for (const evidence of ["evidence/cosmic-metadata.json", "evidence/data-source.md"]) {
		const path = join(root, evidence);
		if (existsSync(path)) {
			items.push({
				kind: "evidence",
				path: evidence,
				action: `复用 ${evidence}，必要时读取并抽取 FormId、字段、实体、表名和插件事件。`,
			});
		}
	}

	for (const path of findMetadataFiles(cwd, 80)) {
		items.push({
			kind: "project-file",
			path,
			action: `优先使用 kd_metadata_collect path=${path} 或 kcode meta ${path} 自动写入当前产品所需 evidence；仅需预览时再用 kd_metadata_parse。`,
		});
	}

	if (existsSync(join(cwd, ".pi", "kd", "mcp-db-connect.yml"))) {
		items.push({
			kind: "mcp-config",
			path: ".pi/kd/mcp-db-connect.yml",
			action: "使用已配置数据库 MCP 只读查询目标业务库元数据；查询结果必须用 kd_metadata_parse 或 kcode metadata --evidence 解析后才能编码。",
		});
	}
	if (existsSync(join(cwd, ".mcp.json")) || existsSync(join(cwd, ".pi", "mcp.json"))) {
		items.push({
			kind: "mcp-config",
			path: existsSync(join(cwd, ".mcp.json")) ? ".mcp.json" : ".pi/mcp.json",
			action: "检查项目 MCP 配置中是否已有只读数据库 server；禁止使用跨库或超级用户连接。",
		});
	}
	if (existsSync(join(cwd, "ok-cosmic.json"))) {
		items.push({
			kind: "official-config",
			path: "ok-cosmic.json",
			action: "优先使用 kd_cosmic_config 和 kd_cosmic_metadata 基于官方 Cosmic 配置查证表单/字段元数据。",
		});
	}

	return {
		items,
		recommendedAction: recommendedMetadataAction(items, run),
	};
}

export function formatMetadataDiscovery(result: MetadataDiscoveryResult): string {
	return [
		`recommendedAction：${result.recommendedAction}`,
		"items：",
		result.items.length > 0
			? result.items.map((item) => `- [${item.kind}] ${item.path}：${item.action}`).join("\n")
			: "- 未发现本地 metadata evidence、项目元数据文件、MCP 配置或 ok-cosmic.json。",
	].join("\n");
}

function recommendedMetadataAction(items: MetadataDiscoveryItem[], run: ActiveRun): string {
	if (items.some((item) => item.kind === "evidence")) return "先读取已有 evidence，不足时再查项目元数据或 MCP。";
	if (items.some((item) => item.kind === "official-config") && run.profile?.platform === "cosmic") {
		return "先运行 kd_cosmic_metadata 查询目标 FormId/字段；缺项目定制元数据时再查 MCP 或本地 fdata。";
	}
	if (items.some((item) => item.kind === "project-file")) return "先用 kd_metadata_collect/kcode meta 自动采集本地元数据文件并写入 evidence。";
	if (items.some((item) => item.kind === "mcp-config")) return "先使用已配置只读 MCP 查询元数据，再解析为 evidence。";
	return "先搜索项目中的 FKERNELXML/fdata/MCP 导出文件；找不到再用 kd_ask_user 确认 FormId 和字段线索。";
}

function findMetadataFiles(cwd: string, limit: number): string[] {
	const found: string[] = [];
	walk(cwd, ".", found, limit, 0);
	return found.sort((left, right) => left.localeCompare(right));
}

function walk(cwd: string, relativeDir: string, found: string[], limit: number, depth: number): void {
	if (found.length >= limit || depth > 4) return;
	const absoluteDir = join(cwd, relativeDir);
	let entries;
	try {
		entries = readdirSync(absoluteDir, { withFileTypes: true });
	} catch {
		return;
	}
	for (const entry of entries) {
		if (found.length >= limit) return;
		const relativePath = relativeDir === "." ? entry.name : join(relativeDir, entry.name);
		if (entry.isDirectory()) {
			if (IGNORED_DIRS.has(entry.name)) continue;
			walk(cwd, relativePath, found, limit, depth + 1);
			continue;
		}
		if (!entry.isFile()) continue;
		if (!METADATA_FILE_PATTERN.test(relativePath)) continue;
		try {
			if (statSync(join(cwd, relativePath)).size > 5 * 1024 * 1024) continue;
		} catch {
			continue;
		}
		found.push(relativePath.replace(/\\/g, "/"));
	}
}