export function normalizeEmail(value: unknown): string | null {
  if (typeof value !== "string") {
    return null;
  }

  const email = value.trim().toLowerCase();

  if (!email.includes("@") || email.length > 254) {
    return null;
  }

  return email;
}

export function normalizePassword(value: unknown): string | null {
  if (typeof value !== "string") {
    return null;
  }

  if (value.length < 10 || value.length > 128) {
    return null;
  }

  return value;
}

export function normalizeDisplayName(value: unknown): string | null {
  if (value === null || value === undefined || value === "") {
    return null;
  }

  if (typeof value !== "string") {
    return null;
  }

  const displayName = value.trim();

  if (displayName.length < 1 || displayName.length > 80) {
    return null;
  }

  return displayName;
}

export function normalizeUserRole(value: unknown): "ADMIN" | "USER" | null {
  if (value === "ADMIN" || value === "USER") {
    return value;
  }

  return null;
}

export function normalizeDashboardTitle(value: unknown): string | null {
  if (typeof value !== "string") {
    return null;
  }

  const title = value.trim();

  if (title.length < 1 || title.length > 80) {
    return null;
  }

  return title;
}

export function normalizeOptionalDashboardSubtitle(value: unknown): string | null {
  if (value === null || value === undefined || value === "") {
    return null;
  }

  if (typeof value !== "string") {
    return null;
  }

  const subtitle = value.trim();

  if (subtitle.length > 120) {
    return null;
  }

  return subtitle.length > 0 ? subtitle : null;
}

export function normalizeThemeColor(value: unknown): string | null {
  if (typeof value !== "string") {
    return null;
  }

  const color = value.trim();

  const shortHexMatch = /^#([0-9a-fA-F]{3})$/.exec(color);

  if (shortHexMatch) {
    const [r, g, b] = shortHexMatch[1].split("");

    return `#${r}${r}${g}${g}${b}${b}`.toLowerCase();
  }

  if (/^#[0-9a-fA-F]{6}$/.test(color)) {
    return color.toLowerCase();
  }

  return null;
}

export function normalizeOptionalLogoUrl(value: unknown): string | null {
  if (value === null || value === undefined || value === "") {
    return null;
  }

  if (typeof value !== "string") {
    return null;
  }

  const trimmed = value.trim();

  if (trimmed.length < 1 || trimmed.length > 2048) {
    return null;
  }

  if (trimmed.startsWith("/") && !trimmed.startsWith("//")) {
    return trimmed;
  }

  try {
    const url = new URL(trimmed);

    if (url.protocol !== "http:" && url.protocol !== "https:") {
      return null;
    }

    return url.toString();
  } catch {
    return null;
  }
}

export function normalizeOptionalImageUrl(value: unknown): string | null {
  if (value === null || value === undefined || value === "") {
    return null;
  }

  if (typeof value !== "string") {
    return null;
  }

  const trimmed = value.trim();

  if (trimmed.length < 1 || trimmed.length > 2048) {
    return null;
  }

  if (trimmed.startsWith("/") && !trimmed.startsWith("//")) {
    return trimmed;
  }

  try {
    const url = new URL(trimmed);

    if (url.protocol !== "http:" && url.protocol !== "https:") {
      return null;
    }

    return url.toString();
  } catch {
    return null;
  }
}

export function normalizeTitle(value: unknown): string | null {
  if (typeof value !== "string") {
    return null;
  }

  const title = value.trim();

  if (title.length < 1 || title.length > 80) {
    return null;
  }

  return title;
}

export function normalizeUrl(value: unknown): string | null {
  if (typeof value !== "string") {
    return null;
  }

  const trimmed = value.trim();

  if (trimmed.length < 3 || trimmed.length > 2048) {
    return null;
  }

  const withProtocol =
    trimmed.startsWith("http://") || trimmed.startsWith("https://") ? trimmed : `https://${trimmed}`;

  try {
    const url = new URL(withProtocol);

    if (url.protocol !== "http:" && url.protocol !== "https:") {
      return null;
    }

    return url.toString();
  } catch {
    return null;
  }
}

export function normalizeOptionalUrl(value: unknown): string | null {
  if (value === null || value === undefined || value === "") {
    return null;
  }

  return normalizeUrl(value);
}

export function normalizePositiveInteger(value: unknown, fallback: number, min: number, max: number): number {
  const parsed = typeof value === "number" ? value : Number.parseInt(String(value), 10);

  if (!Number.isFinite(parsed) || parsed < min || parsed > max) {
    return fallback;
  }

  return parsed;
}