import { DomainError } from "./domain-errors.js";

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

export function normalizeFilePath(record: Record<string, unknown>): void {
  const hasPath = typeof record.path === "string";
  const hasFilePath = typeof record.file_path === "string";
  if (!hasPath && hasFilePath) {
    console.warn(
      `[DEPRECATED] "file_path" is deprecated, use "path" instead (payload). Received file_path=${JSON.stringify(record.file_path)}. This alias will be removed in a future version.`,
    );
    record.path = record.file_path as string;

    delete record.file_path;
    return;
  }
  if (hasFilePath) {
    console.warn(
      `[DEPRECATED] "file_path" is deprecated, use "path" instead (payload). Received file_path=${JSON.stringify(record.file_path)}. This alias will be removed in a future version.`,
    );

    delete record.file_path;
    return;
  }
  if ("file_path" in record) {
    const fp = (record as Record<string, unknown>).file_path;
    if (fp !== undefined) {
      console.warn(
        `[DEPRECATED] "file_path" is deprecated, use "path" instead (payload). Received file_path=${JSON.stringify(fp)}. This alias will be removed in a future version.`,
      );
    }

    delete record.file_path;
  }
}

export function splitLines(text: string): string[] {
  if (text.length === 0) return [""];
  const lines = text.split("\n");
  return text.endsWith("\n") ? lines.slice(0, -1) : lines;
}

export function visLines(text: string): string[] {
  if (text.length === 0) return [];
  const lines = text.split("\n");
  return text.endsWith("\n") ? lines.slice(0, -1) : lines;
}

export function rejectUnknownFields(
  obj: Record<string, unknown>,
  allowed: Set<string>,
  label: string,
  hint?: string,
): void {
  const unknown = Object.keys(obj).filter((key) => !allowed.has(key));
  if (unknown.length > 0) {
    const suffix = hint ? ` ${hint}` : "";
    throw new DomainError("E_BAD_PAYLOAD", {
      message: `${label} contains unknown or unsupported fields: ${unknown.join(", ")}.${suffix}`,
    });
  }
}

export function cntDiff(diff: string, marker: "+" | "-"): number {
  if (!diff) return 0;
  let count = 0;
  for (const line of diff.split("\n")) {
    if (line.startsWith(marker) && !line.startsWith(`${marker}${marker}${marker}`)) {
      count += 1;
    }
  }
  return count;
}

export function abortIf(signal?: AbortSignal): void {
  if (signal?.aborted) throw new Error("Operation aborted");
}

export function errCode(error: unknown): string | undefined {
  if (error instanceof Error) {
    return (error as NodeJS.ErrnoException).code;
  }
  return undefined;
}

export function lastNonEmptyIndex(lines: string[]): number {
  for (let i = lines.length - 1; i >= 0; i--) {
    if (lines[i]!.length > 0) return i;
  }
  return -1;
}

export function firstNonEmptyIndex(lines: string[]): number {
  for (let i = 0; i < lines.length; i++) {
    if (lines[i]!.length > 0) return i;
  }
  return -1;
}

export function lastNonEmpty(lines: string[]): string | undefined {
  const idx = lastNonEmptyIndex(lines);
  return idx >= 0 ? lines[idx] : undefined;
}

export function firstNonEmpty(lines: string[]): string | undefined {
  const idx = firstNonEmptyIndex(lines);
  return idx >= 0 ? lines[idx] : undefined;
}

export function clipLine(line: string, maxLen = 200): string {
  const flat = line.replace(/\n/g, "\\n");
  return flat.length > maxLen ? `${flat.slice(0, maxLen)}...` : flat;
}