import { davError } from "@/worker/dav/http";
import { parseIfHeader, positiveLockTokens, type ParsedIfHeader } from "@/worker/dav/if-header";

export interface FileDavWriteRequest {
  ifMatch: string | null;
  ifNoneMatch: string | null;
  ifHeader: ParsedIfHeader;
  lockTokens: string[];
  nowMs: number;
}

export function parseContentLength(request: Request): number | null {
  const value = request.headers.get("content-length");
  if (!value) return null;
  const parsed = Number.parseInt(value, 10);
  return Number.isFinite(parsed) && parsed >= 0 ? parsed : null;
}

export function requestIfHeader(request: Request): { ok: true; header: ParsedIfHeader } | Response {
  const parsed = parseIfHeader(request.headers.get("if"));
  if (!parsed.ok) return davError(400, parsed.message);
  return parsed;
}

export function readFileDavWriteRequest(request: Request, nowMs = Date.now()): FileDavWriteRequest | Response {
  const parsedIf = requestIfHeader(request);
  if (parsedIf instanceof Response) return parsedIf;
  return {
    ifMatch: request.headers.get("if-match"),
    ifNoneMatch: request.headers.get("if-none-match"),
    ifHeader: parsedIf.header,
    lockTokens: positiveLockTokens(parsedIf.header),
    nowMs,
  };
}

export function validateDeleteDepth(value: string | null): Response | null {
  // RFC 4918 9.6.1: DELETE on a collection is Depth: infinity; other values are invalid.
  const normalized = value?.trim().toLowerCase() ?? null;
  return normalized !== null && normalized !== "infinity" ? davError(400, "DELETE Depth must be infinity") : null;
}

export function readCopyDepth(value: string | null): "0" | "infinity" | Response {
  // RFC 4918 9.8.3: COPY Depth must be absent, "0", or "infinity".
  const normalized = value?.trim().toLowerCase() ?? null;
  if (normalized !== null && normalized !== "0" && normalized !== "infinity") {
    return davError(400, "COPY Depth must be 0 or infinity");
  }
  return normalized === "0" ? "0" : "infinity";
}

export function validateMoveDepth(value: string | null): Response | null {
  // RFC 4918 9.9.3: MOVE on a collection is Depth: infinity; Depth: 0 is not permitted.
  const normalized = value?.trim().toLowerCase() ?? null;
  return normalized !== null && normalized !== "infinity" ? davError(400, "MOVE Depth must be infinity") : null;
}