/* Copyright 2026 Marimo. All rights reserved. */

import { z } from "zod";

const DetailsSchema = z.object({
  detail: z.string(),
});

const ErrorSchema = z.object({
  error: z.string(),
});

export function prettyError(error: unknown): string {
  if (!error) {
    return "Unknown error";
  }
  if (error instanceof Error) {
    const details = DetailsSchema.safeParse(error.cause);
    if (details.success) {
      return details.data.detail;
    }
    return maybeExtractDetails(error.message);
  }
  if (typeof error === "object") {
    const details = DetailsSchema.safeParse(error);
    if (details.success) {
      return details.data.detail;
    }
    const parsed = ErrorSchema.safeParse(error);
    if (parsed.success) {
      return parsed.data.error;
    }
  }
  try {
    return JSON.stringify(error);
  } catch {
    return String(error);
  }
}

function maybeExtractDetails(message: string): string {
  const parsed = safeJSONParse(message);
  if (!parsed) {
    return message;
  }
  const details = DetailsSchema.safeParse(parsed);
  if (details.success) {
    return details.data.detail;
  }
  const error = ErrorSchema.safeParse(parsed);
  if (error.success) {
    return error.data.error;
  }
  return message;
}

function safeJSONParse(message: string): unknown {
  try {
    return JSON.parse(message);
  } catch {
    return message;
  }
}

/**
 * A failed HTTP response. Carries the status code so callers can branch on it
 * (e.g. treat a capability 403 as a benign viewer state). The response body is
 * kept as `cause` so `prettyError` can surface its `detail`.
 */
export class HTTPError extends Error {
  public readonly status: number;

  public constructor(status: number, statusText: string, body?: unknown) {
    super(statusText, { cause: body });
    this.name = "HTTPError";
    this.status = status;
  }
}

export class CellNotInitializedError extends Error {
  public constructor(
    message = "The cell containing this UI element has not been run yet. Please run the cell first.",
  ) {
    super(message);
    this.name = "CellNotInitializedError";
  }
}

export class FunctionNotFoundError extends Error {
  public constructor(
    message = "This UI element could not reach its function on the kernel. Try re-running the cell.",
  ) {
    super(message);
    this.name = "FunctionNotFoundError";
  }
}

export class NoKernelConnectedError extends Error {
  public constructor(message = "Not yet connected to a kernel.") {
    super(message);
    this.name = "NoKernelConnectedError";
  }
}