// OpenRouter-powered commit summary + small avatar helpers.
import { p4, OpenedFile, statusOf } from "./p4";
import { LANG } from "./i18n";

// AI replies follow the app's UI language
const LANG_NAMES: Record<string, string> = { en: "English", ru: "Russian", de: "German", fr: "French", es: "Spanish" };
function langName(): string { return LANG_NAMES[LANG] || "English"; }

// fixed model — no user-facing AI settings
export const DEFAULT_MODEL = "openai/gpt-4o-mini";

// the key is baked into the binary at build time (src-tauri/openrouter.key)
export async function resolveKey(): Promise<string> {
  try { return (await p4.readAiKey()) || ""; } catch { return ""; }
}

// generate a commit summary + description from the changed files
export async function aiSummary(files: OpenedFile[]): Promise<{ summary: string; description: string }> {
  const key = await resolveKey();
  if (!key) throw new Error("No OpenRouter API key baked into this build");
  const list = files.slice(0, 200).map((f) => `${statusOf(f.action).ch} ${f.depotFile || ""}`).join("\n");
  const res = await fetch("https://openrouter.ai/api/v1/chat/completions", {
    method: "POST",
    headers: { Authorization: `Bearer ${key}`, "Content-Type": "application/json", "X-Title": "Exbyte Depot" },
    body: JSON.stringify({
      model: DEFAULT_MODEL,
      max_tokens: 300,
      temperature: 0.3,
      messages: [
        { role: "system", content: `You write concise commit messages for a Perforce/Unreal project. Given a list of changed files (+ added, ± edited, − deleted), reply with ONE short imperative summary line (under 72 chars, no trailing period), then a blank line, then an optional 1-3 line description. Plain text only — no markdown, no code fences, no quotes. Write the entire reply in ${langName()}.` },
        { role: "user", content: `Changed files:\n${list}` },
      ],
    }),
  });
  if (!res.ok) {
    const txt = await res.text().catch(() => "");
    throw new Error(`OpenRouter ${res.status}: ${txt.slice(0, 180)}`);
  }
  const data = await res.json();
  const content: string = (data?.choices?.[0]?.message?.content || "").trim();
  if (!content) throw new Error("Empty AI response");
  const lines = content.split("\n");
  const summary = (lines[0] || "").replace(/^["'`*]+|["'`*]+$/g, "").trim();
  const description = lines.slice(1).join("\n").trim();
  return { summary, description };
}

// briefly explain what a source file does (2–4 sentences, plain text)
export async function aiExplainCode(name: string, code: string): Promise<string> {
  const key = await resolveKey();
  if (!key) throw new Error("No OpenRouter API key baked into this build");
  const snippet = code.slice(0, 14000); // cap the payload
  const res = await fetch("https://openrouter.ai/api/v1/chat/completions", {
    method: "POST",
    headers: { Authorization: `Bearer ${key}`, "Content-Type": "application/json", "X-Title": "Exbyte Depot" },
    body: JSON.stringify({
      model: DEFAULT_MODEL,
      max_tokens: 260,
      temperature: 0.2,
      messages: [
        { role: "system", content: `You explain source files for a Perforce/Unreal C++ (and general game) project. Given one file, reply with a SHORT plain-text summary (2–4 sentences) of what it does and its role in the project. No markdown, no code fences, no headings, no bullet points — a single tight paragraph. Write the entire reply in ${langName()}.` },
        { role: "user", content: `File: ${name}\n\n${snippet}` },
      ],
    }),
  });
  if (!res.ok) {
    const txt = await res.text().catch(() => "");
    throw new Error(`OpenRouter ${res.status}: ${txt.slice(0, 180)}`);
  }
  const data = await res.json();
  const content: string = (data?.choices?.[0]?.message?.content || "").trim();
  if (!content) throw new Error("Empty AI response");
  return content;
}

// --- persistent cache of AI code summaries (removed only via the × button) ---
const EXPL_KEY = "exd-explain";
type ExplEntry = { k: string; v: string };
function loadExpl(): ExplEntry[] {
  try { const r = localStorage.getItem(EXPL_KEY); const l = r ? JSON.parse(r) : []; return Array.isArray(l) ? l : []; } catch { return []; }
}
function storeExpl(list: ExplEntry[]) { try { localStorage.setItem(EXPL_KEY, JSON.stringify(list)); } catch {} }
export function getExplain(key: string): string | null {
  return loadExpl().find((e) => e.k === key)?.v ?? null;
}
export function saveExplain(key: string, text: string) {
  const list = loadExpl().filter((e) => e.k !== key);
  list.push({ k: key, v: text });
  storeExpl(list.slice(-80)); // keep the 80 most recent
}
export function dropExplain(key: string) {
  storeExpl(loadExpl().filter((e) => e.k !== key));
}

// --- avatar helpers ---
export function initials(name: string, user: string): string {
  const n = (name || "").trim();
  if (n) {
    const p = n.split(/\s+/);
    return (p[0][0] + (p[1]?.[0] || "")).toUpperCase();
  }
  return (user || "?").slice(0, 2).toUpperCase();
}
export function avatarColor(seed: string): string {
  let h = 0;
  for (let i = 0; i < seed.length; i++) h = (h * 31 + seed.charCodeAt(i)) >>> 0;
  return `hsl(${h % 360} 52% 52%)`;
}
// activity level from a unix-epoch last-access string
export function activity(access?: string): "active" | "recent" | "idle" {
  const n = Number(access || 0) * 1000;
  if (!n) return "idle";
  const ago = Date.now() - n;
  if (ago < 60 * 60 * 1000) return "active";        // < 1h
  if (ago < 24 * 60 * 60 * 1000) return "recent";   // < 1d
  return "idle";
}