import "server-only";

import { prisma } from "@/lib/db";

// Fixed id of the one-and-only AiSettings row (see prisma/schema.prisma).
const SETTINGS_ID = "singleton";

export interface AiSettingsView {
  apiUrl: string | null;
  model: string | null;
  hasApiKey: boolean;
  // Last 4 characters only (e.g. "••••••••f00d") -- enough to confirm
  // *which* key is configured without ever sending the real one back to
  // the browser. Null when no key is set.
  apiKeyMasked: string | null;
}

function maskKey(key: string): string {
  return `••••••••${key.slice(-4)}`;
}

/**
 * Builds an OpenAI-compatible endpoint URL from an admin-entered base URL
 * (e.g. "https://host/api/v1") plus a path (e.g. "models",
 * "chat/completions"). Shared by every call site that talks to the
 * configured provider, so the trailing-slash handling only lives once --
 * `new URL(path, base)` silently drops the base's last path segment
 * (turning ".../v1" into ".../models" instead of ".../v1/models") unless
 * the base ends in "/".
 */
export function joinApiUrl(apiUrl: string, path: string): URL {
  const withTrailingSlash = apiUrl.endsWith("/") ? apiUrl : `${apiUrl}/`;
  return new URL(path, withTrailingSlash);
}

/** The client-safe view of the AI settings -- never includes the real key. */
export async function getAiSettingsView(): Promise<AiSettingsView> {
  const settings = await prisma.aiSettings.findUnique({ where: { id: SETTINGS_ID } });
  return {
    apiUrl: settings?.apiUrl ?? null,
    model: settings?.model ?? null,
    hasApiKey: !!settings?.apiKey,
    apiKeyMasked: settings?.apiKey ? maskKey(settings.apiKey) : null,
  };
}

/**
 * The real, unmasked key -- for server-side use only (calling the
 * provider). Never pass this to a client component or return it from a
 * Server Action.
 */
export async function getAiCredentials(): Promise<{
  apiUrl: string | null;
  apiKey: string | null;
}> {
  const settings = await prisma.aiSettings.findUnique({ where: { id: SETTINGS_ID } });
  return { apiUrl: settings?.apiUrl ?? null, apiKey: settings?.apiKey ?? null };
}

/**
 * `apiKey` omitted (or empty) means "leave the currently saved key
 * alone" -- the form field is never prefilled with the real key, so
 * there's nothing to resubmit when the admin isn't changing it.
 */
export async function saveAiSettings(data: {
  apiUrl: string;
  apiKey?: string;
  model: string;
}): Promise<void> {
  await prisma.aiSettings.upsert({
    where: { id: SETTINGS_ID },
    create: {
      id: SETTINGS_ID,
      apiUrl: data.apiUrl,
      apiKey: data.apiKey || null,
      model: data.model,
    },
    update: {
      apiUrl: data.apiUrl,
      model: data.model,
      ...(data.apiKey ? { apiKey: data.apiKey } : {}),
    },
  });
}