type StdioMcpServerLaunchConfig = {
  command: string;
  args?: string[];
  env?: Record<string, string>;
  cwd?: string;
};

type StdioMcpServerLaunchResult =
  | { ok: true; config: StdioMcpServerLaunchConfig }
  | { ok: false; reason: string };

function isRecord(value: unknown): value is Record<string, unknown> {
  return value !== null && typeof value === "object" && !Array.isArray(value);
}

function toStringRecord(value: unknown): Record<string, string> | undefined {
  if (!isRecord(value)) {
    return undefined;
  }
  const entries = Object.entries(value)
    .map(([key, entry]) => {
      if (typeof entry === "string") {
        return [key, entry] as const;
      }
      if (typeof entry === "number" || typeof entry === "boolean") {
        return [key, String(entry)] as const;
      }
      return null;
    })
    .filter((entry): entry is readonly [string, string] => entry !== null);
  return entries.length > 0 ? Object.fromEntries(entries) : undefined;
}

function toStringArray(value: unknown): string[] | undefined {
  if (!Array.isArray(value)) {
    return undefined;
  }
  const entries = value.filter((entry): entry is string => typeof entry === "string");
  return entries.length > 0 ? entries : [];
}

export function resolveStdioMcpServerLaunchConfig(raw: unknown): StdioMcpServerLaunchResult {
  if (!isRecord(raw)) {
    return { ok: false, reason: "server config must be an object" };
  }
  if (typeof raw.command !== "string" || raw.command.trim().length === 0) {
    if (typeof raw.url === "string" && raw.url.trim().length > 0) {
      return {
        ok: false,
        reason: "only stdio MCP servers are supported right now",
      };
    }
    return { ok: false, reason: "its command is missing" };
  }
  const cwd =
    typeof raw.cwd === "string" && raw.cwd.trim().length > 0
      ? raw.cwd
      : typeof raw.workingDirectory === "string" && raw.workingDirectory.trim().length > 0
        ? raw.workingDirectory
        : undefined;
  return {
    ok: true,
    config: {
      command: raw.command,
      args: toStringArray(raw.args),
      env: toStringRecord(raw.env),
      cwd,
    },
  };
}

export function describeStdioMcpServerLaunchConfig(config: StdioMcpServerLaunchConfig): string {
  const args =
    Array.isArray(config.args) && config.args.length > 0 ? ` ${config.args.join(" ")}` : "";
  const cwd = config.cwd ? ` (cwd=${config.cwd})` : "";
  return `${config.command}${args}${cwd}`;
}

export type { StdioMcpServerLaunchConfig, StdioMcpServerLaunchResult };