// Works out which provider an API key belongs to, so users never have to know
// what a Base URL is.
//
// The old flow asked for three things — Base URL, model name and key — on the
// first screen a non-technical user ever saw. Every key in practice announces
// its own provider through its prefix, so ask for the key and derive the rest.

// Order matters: the longest, most specific prefixes are checked first, because
// several providers issue keys that also start with "sk-".
const PROVIDERS = [
  {
    id: 'anthropic',
    label: 'Anthropic Claude',
    prefixes: ['sk-ant-'],
    baseUrl: 'https://api.anthropic.com/v1',
    model: 'claude-sonnet-4-20250514',
    models: ['claude-sonnet-4-20250514', 'claude-opus-4-20250514', 'claude-haiku-4-5-20251001'],
  },
  {
    id: 'openrouter',
    label: 'OpenRouter',
    prefixes: ['sk-or-v1-', 'sk-or-'],
    baseUrl: 'https://openrouter.ai/api/v1',
    model: 'anthropic/claude-sonnet-4',
    models: ['anthropic/claude-sonnet-4', 'openai/gpt-4o', 'google/gemini-2.5-flash'],
  },
  {
    id: 'google',
    label: 'Google Gemini',
    // Google AI Studio now issues Auth keys (AQ.Ab…) alongside legacy Standard keys (AIzaSy…).
    prefixes: ['AQ.', 'AIza'],
    baseUrl: 'https://generativelanguage.googleapis.com/v1beta/openai',
    // New AI Studio accounts often cannot use 2.5-flash yet (404). Try 2.0 first.
    model: 'gemini-2.0-flash',
    models: ['gemini-2.0-flash', 'gemini-flash-latest', 'gemini-2.5-flash', 'gemini-2.5-flash-lite', 'gemini-2.5-pro'],
  },
  {
    id: 'groq',
    label: 'Groq',
    prefixes: ['gsk_'],
    baseUrl: 'https://api.groq.com/openai/v1',
    model: 'llama-3.3-70b-versatile',
    models: ['llama-3.3-70b-versatile', 'llama-3.1-8b-instant'],
  },
  {
    id: 'sealion',
    label: 'SEA-LION',
    prefixes: ['sk-sealion-'],
    baseUrl: 'https://api.sea-lion.ai/v1',
    model: 'aisingapore/Qwen-SEA-LION-v4.5-27B-IT',
    models: ['aisingapore/Qwen-SEA-LION-v4.5-27B-IT', 'aisingapore/Llama-SEA-LION-v3.5-70B-R'],
  },
  {
    id: 'openai',
    label: 'OpenAI',
    prefixes: ['sk-proj-', 'sk-svcacct-', 'sk-'],
    baseUrl: 'https://api.openai.com/v1',
    model: 'gpt-4o',
    models: ['gpt-4o', 'gpt-4o-mini', 'o3-mini'],
  },
];

export function detectProvider(rawKey) {
  const key = String(rawKey ?? '').trim();
  if (!key) return null;
  for (const provider of PROVIDERS) {
    if (provider.prefixes.some((prefix) => key.startsWith(prefix))) {
      return { id: provider.id, label: provider.label, baseUrl: provider.baseUrl, model: provider.model, models: provider.models };
    }
  }
  return null;
}

// Maps a failed request to a message key the UI can translate. Every branch has
// to name something the user can actually do next — "401 Unauthorized" on its
// own tells a non-technical user nothing.
export function classifyFailure({ status, code } = {}) {
  if (code === 'ENOTFOUND' || code === 'EAI_AGAIN' || code === 'ECONNREFUSED') return 'key.err_offline';
  if (code === 'ETIMEDOUT' || code === 'UND_ERR_CONNECT_TIMEOUT' || code === 'ABORT_ERR') return 'key.err_timeout';
  if (status === 400 || status === 401 || status === 403) return 'key.err_rejected';
  if (status === 429) return 'key.err_quota';
  if (status === 404) return 'key.err_model';
  if (typeof status === 'number' && status >= 500) return 'key.err_provider_down';
  return 'key.err_unknown';
}

export function listProviders() {
  return PROVIDERS.map(({ id, label, baseUrl, model, models }) => ({ id, label, baseUrl, model, models }));
}

// Google rotates model availability per account. When the first choice 404s, try the rest.
export function modelsToTry(provider, requestedModel) {
  const primary = String(requestedModel || provider?.model || '').trim();
  if (provider?.id === 'google') {
    return [...new Set([primary, provider.model, ...(provider.models || [])].filter(Boolean))];
  }
  return primary ? [primary] : [];
}

// AQ auth keys only work on the OpenAI-compatible surface. Ask Google which models
// this key can actually see instead of guessing from a static list.
export async function discoverGoogleOpenAiModels(baseUrl, apiKey) {
  const root = String(baseUrl || '').replace(/\/+$/, '');
  if (!root || !apiKey) return [];
  try {
    const res = await fetch(`${root}/models`, {
      headers: { Authorization: `Bearer ${apiKey}` },
    });
    if (!res.ok) return [];
    const body = await res.json();
    const rows = body.data || body.models || [];
    return rows
      .map((m) => String(m.id || m.name || '').replace(/^models\//, ''))
      .filter(Boolean);
  } catch {
    return [];
  }
}