import { ECHO_ENDPOINT, BUILD_INSTRUCTIONS, geminiFailure } from "./gemini-policy";

export async function buildSite(sessionId: string, request: string, previous?: string, userId?: string) {
  const key = process.env["GEMINI_API_KEY"];
  if (!key) return { error: "Gemini key is missing." } as const;
  const text = previous
    ? `Current page HTML:\n${previous.slice(0, 60000)}\n\nApply this request (keep what isn't changed): ${request}`
    : request;
  const send = () => fetch(ECHO_ENDPOINT, {
    method: "POST",
    headers: { "Content-Type": "application/json", "x-goog-api-key": key },
    body: JSON.stringify({ systemInstruction: { parts: [{ text: BUILD_INSTRUCTIONS }] }, contents: [{ role: "user", parts: [{ text }] }] }),
  });
  let res = await send();
  // One retry only for Google's temporary overload errors (never for quota 429).
  if (res.status === 500 || res.status === 503) res = await send();
  if (!res.ok) return { error: geminiFailure(res.status) } as const;
  const json = (await res.json()) as { candidates?: { content?: { parts?: { text?: string; thought?: boolean }[] } }[] };
  let html = (json.candidates?.[0]?.content?.parts ?? []).filter((p) => !p.thought).map((p) => p.text ?? "").join("").trim();
  html = html.replace(/^```(?:html)?\s*/i, "").replace(/```\s*$/, "").trim();
  if (!/<html|<body|<div/i.test(html)) return { error: "Gemini did not return a page." } as const;
  const { supabaseAdmin } = await import("@/integrations/supabase/client.server");
  const { data, error } = await supabaseAdmin.from("voice_builds").insert({ session_id: sessionId, prompt: request, html, user_id: userId ?? null }).select("id").single();
  if (error || !data) return { error: "The preview was built but could not be saved." } as const;
  return { id: data.id, html } as const;
}