import { chmod, mkdir, mkdtemp, rm, stat } from "node:fs/promises";
import { createReadStream } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { spawn } from "node:child_process";
import type { PrismaClient } from "@prisma/client";
import {
  resolveActiveFeishuApplication,
  type ResolvedFeishuApplication,
} from "../connections/feishuApplicationConnections.js";
import type { LocalSecretEnvelope } from "../security/secretEnvelope.js";
import {
  WorkspaceFileBoundaryError,
  writeNewWorkspaceFileNoFollow,
} from "../security/workspaceFiles.js";

const DEFAULT_TIMEOUT_MS = 180_000;
const MAX_COMMAND_OUTPUT_BYTES = 1024 * 1024;
const DEFAULT_CLI_PATH = "/usr/local/bin:/usr/bin:/bin";

const SAFE_CLI_ENV_KEYS = [
  "PATH",
  "LANG",
  "LC_ALL",
  "LC_CTYPE",
  "TZ",
  "HTTP_PROXY",
  "HTTPS_PROXY",
  "ALL_PROXY",
  "NO_PROXY",
  "http_proxy",
  "https_proxy",
  "all_proxy",
  "no_proxy",
  "NODE_USE_ENV_PROXY",
] as const;

export interface FeishuBotCliDownloadRequest {
  readonly messageId: string;
  readonly fileKey: string;
  readonly resourceType: "image" | "file";
  readonly workspaceRoot: string;
  readonly workspaceDir: string;
  readonly workspaceRelativePath: string;
  readonly maxBytes?: number | undefined;
}

export interface FeishuBotCli {
  downloadResource(request: FeishuBotCliDownloadRequest): Promise<string>;
}

export interface FeishuBotCliOptions {
  readonly organizationId: string;
  readonly prisma: PrismaClient;
  readonly secretEnvelope: LocalSecretEnvelope;
  readonly binary?: string | undefined;
  readonly timeoutMs?: number | undefined;
  readonly resolveCredential?: (() => Promise<ResolvedFeishuApplication>) | undefined;
}

interface CommandResult {
  readonly stdout: string;
  readonly stderr: string;
}

/**
 * Runs the real lark-cli as a Hub-owned bot operation.
 *
 * The CLI receives the App Secret over stdin and gets a disposable HOME. No
 * Feishu credential is placed in Agent environment, project files, argv, or
 * the process-global CLI configuration. The caller still owns project/chat
 * authorization; this adapter only performs bot-identity transport.
 */
export function createFeishuBotCli(options: FeishuBotCliOptions): FeishuBotCli {
  const resolveCredential = options.resolveCredential ?? (() => resolveActiveFeishuApplication(
    options.prisma,
    options.secretEnvelope,
    { organizationId: options.organizationId },
  ));
  const timeoutMs = options.timeoutMs ?? DEFAULT_TIMEOUT_MS;

  return {
    async downloadResource(request): Promise<string> {
      const credential = await resolveCredential();
      const root = await mkdtemp(join(tmpdir(), "cph-feishu-bot-cli-"), { encoding: "utf8" });
      const home = join(root, "home");
      await mkdirPrivate(home);
      const cliEnv = buildCliEnv(home);
      const cliBinary = options.binary ?? process.env["HUB_FEISHU_CLI_BIN"] ?? "lark-cli";
      const temporaryName = "resource.bin";
      const temporaryPath = join(home, temporaryName);

      try {
        await runCli(
          cliBinary,
          ["config", "init", "--app-id", credential.appId, "--app-secret-stdin", "--brand", "feishu"],
          { cwd: root, env: cliEnv, stdin: `${credential.appSecret}\n`, timeoutMs, label: "config init" },
        );
        await runCli(
          cliBinary,
          [
            "im",
            "+messages-resources-download",
            "--as",
            "bot",
            "--message-id",
            request.messageId,
            "--file-key",
            request.fileKey,
            "--type",
            request.resourceType,
            "--output",
            temporaryName,
          ],
          { cwd: home, env: cliEnv, timeoutMs, label: "resource download" },
        );

        const metadata = await stat(temporaryPath);
        if (!metadata.isFile()) {
          throw new Error("lark-cli resource download did not produce a regular file");
        }
        if (request.maxBytes !== undefined && metadata.size > request.maxBytes) {
          throw new WorkspaceFileBoundaryError(
            `Feishu resource exceeds ${request.maxBytes} bytes: ${request.fileKey}`,
            request.workspaceRelativePath,
            "limit",
          );
        }

        return await writeNewWorkspaceFileNoFollow(
          request.workspaceRoot,
          request.workspaceDir,
          request.workspaceRelativePath,
          createReadStream(temporaryPath),
          request.maxBytes,
        );
      } finally {
        await rm(root, { recursive: true, force: true });
      }
    },
  };
}

async function mkdirPrivate(path: string): Promise<void> {
  await mkdir(path, { recursive: true, mode: 0o700 });
  await chmod(path, 0o700);
}

function buildCliEnv(home: string): NodeJS.ProcessEnv {
  const env: NodeJS.ProcessEnv = {};
  for (const name of SAFE_CLI_ENV_KEYS) {
    const value = process.env[name];
    if (value !== undefined) env[name] = value;
  }
  if (env.PATH === undefined || env.PATH.trim() === "") env.PATH = DEFAULT_CLI_PATH;
  env.HOME = home;
  env.XDG_CONFIG_HOME = join(home, ".config");
  env.XDG_CACHE_HOME = join(home, ".cache");
  env.XDG_STATE_HOME = join(home, ".state");
  return env;
}

async function runCli(
  binary: string,
  args: readonly string[],
  input: {
    readonly cwd: string;
    readonly env: NodeJS.ProcessEnv;
    readonly stdin?: string | undefined;
    readonly timeoutMs: number;
    readonly label: string;
  },
): Promise<CommandResult> {
  return new Promise<CommandResult>((resolve, reject) => {
    const child = spawn(binary, args, {
      cwd: input.cwd,
      env: input.env,
      stdio: ["pipe", "pipe", "pipe"],
    });
    let stdout = "";
    let stderr = "";
    let outputBytes = 0;
    let settled = false;
    const timer = setTimeout(() => {
      child.kill("SIGTERM");
      finish(new Error(`lark-cli ${input.label} timed out after ${input.timeoutMs}ms`));
    }, input.timeoutMs);

    const appendOutput = (target: "stdout" | "stderr", chunk: Buffer | string): void => {
      if (outputBytes >= MAX_COMMAND_OUTPUT_BYTES) return;
      const text = typeof chunk === "string" ? chunk : chunk.toString("utf8");
      const remaining = MAX_COMMAND_OUTPUT_BYTES - outputBytes;
      const bounded = text.slice(0, remaining);
      outputBytes += Buffer.byteLength(bounded);
      if (target === "stdout") stdout += bounded;
      else stderr += bounded;
    };

    const finish = (error?: Error, result?: CommandResult): void => {
      if (settled) return;
      settled = true;
      clearTimeout(timer);
      if (error !== undefined) reject(error);
      else resolve(result!);
    };

    child.stdout.on("data", (chunk: Buffer | string) => appendOutput("stdout", chunk));
    child.stderr.on("data", (chunk: Buffer | string) => appendOutput("stderr", chunk));
    child.once("error", (error) => {
      finish(error instanceof Error ? error : new Error(String(error)));
    });
    child.once("close", (code, signal) => {
      if (code !== 0) {
        const detail = (stderr.trim() || stdout.trim()).slice(0, 500);
        const status = code === null ? signal ?? "signal" : `exit ${code}`;
        finish(new Error(
          detail === ""
            ? `lark-cli ${input.label} failed (${status})`
            : `lark-cli ${input.label} failed (${status}): ${detail}`,
        ));
        return;
      }
      finish(undefined, { stdout, stderr });
    });
    child.stdin.end(input.stdin);
  });
}