/**
 * model alias registry.
 *
 * slugs use the format `provider/model-id` (e.g. "anthropic/claude-opus").
 * bump `resolve` when a new model generation ships — the alias (slug) stays stable.
 */

// ── types ──────────────────────────────────────────────────────────────────────

export interface ModelAlias {
  /** stable alias stored in DB, e.g. "anthropic/claude-opus" */
  slug: string;
  /** provider key (matches providers keys) */
  provider: string;
  /** human-readable name shown in dropdowns */
  displayName: string;
  /** concrete models.dev specifier, e.g. "anthropic/claude-opus-4-6" */
  resolve: string;
  /** top-tier pick for this provider — preferred during auto-select */
  recommended: boolean;
}

interface ModelDef {
  displayName: string;
  /** concrete models.dev specifier, e.g. "anthropic/claude-opus-4-6" */
  resolve: string;
  recommended?: boolean;
}

export interface ProviderConfig {
  displayName: string;
  envVars: readonly string[];
  models: Record<string, ModelDef>;
}

// ── provider + model definitions ────────────────────────────────────────────────

function provider(config: ProviderConfig): ProviderConfig {
  return config;
}

export const providers = {
  anthropic: provider({
    displayName: "Anthropic",
    envVars: ["ANTHROPIC_API_KEY"],
    models: {
      "claude-opus": {
        displayName: "Claude Opus",
        resolve: "anthropic/claude-opus-4-6",
        recommended: true,
      },
      "claude-sonnet": { displayName: "Claude Sonnet", resolve: "anthropic/claude-sonnet-4-6" },
      "claude-haiku": { displayName: "Claude Haiku", resolve: "anthropic/claude-haiku-4-5" },
    },
  }),
  openai: provider({
    displayName: "OpenAI",
    envVars: ["OPENAI_API_KEY"],
    models: {
      "gpt-codex": { displayName: "GPT Codex", resolve: "openai/gpt-5.3-codex", recommended: true },
      "gpt-codex-mini": { displayName: "GPT Codex Mini", resolve: "openai/codex-mini-latest" },
      o3: { displayName: "O3", resolve: "openai/o3" },
    },
  }),
  google: provider({
    displayName: "Google",
    envVars: ["GOOGLE_GENERATIVE_AI_API_KEY", "GEMINI_API_KEY"],
    models: {
      "gemini-pro": {
        displayName: "Gemini Pro",
        resolve: "google/gemini-3.1-pro-preview",
        recommended: true,
      },
      "gemini-flash": { displayName: "Gemini Flash", resolve: "google/gemini-3-flash-preview" },
    },
  }),
  xai: provider({
    displayName: "xAI",
    envVars: ["XAI_API_KEY"],
    models: {
      grok: { displayName: "Grok", resolve: "xai/grok-4", recommended: true },
      "grok-fast": { displayName: "Grok Fast", resolve: "xai/grok-4-fast" },
      "grok-code-fast": { displayName: "Grok Code Fast", resolve: "xai/grok-code-fast-1" },
    },
  }),
  deepseek: provider({
    displayName: "DeepSeek",
    envVars: ["DEEPSEEK_API_KEY"],
    models: {
      "deepseek-reasoner": {
        displayName: "DeepSeek Reasoner",
        resolve: "deepseek/deepseek-reasoner",
        recommended: true,
      },
      "deepseek-chat": { displayName: "DeepSeek Chat", resolve: "deepseek/deepseek-chat" },
    },
  }),
  moonshotai: provider({
    displayName: "Moonshot AI",
    envVars: ["MOONSHOT_API_KEY"],
    models: {
      "kimi-k2": { displayName: "Kimi K2", resolve: "moonshotai/kimi-k2.5", recommended: true },
    },
  }),
  opencode: provider({
    displayName: "OpenCode",
    envVars: ["OPENCODE_API_KEY"],
    models: {
      "big-pickle": {
        displayName: "Big Pickle",
        resolve: "opencode/big-pickle",
        recommended: true,
      },
      "claude-opus": { displayName: "Claude Opus", resolve: "opencode/claude-opus-4-6" },
      "claude-sonnet": { displayName: "Claude Sonnet", resolve: "opencode/claude-sonnet-4-6" },
      "claude-haiku": { displayName: "Claude Haiku", resolve: "opencode/claude-haiku-4-5" },
      "gpt-codex": { displayName: "GPT Codex", resolve: "opencode/gpt-5.3-codex" },
      "gemini-pro": { displayName: "Gemini Pro", resolve: "opencode/gemini-3.1-pro" },
      "gemini-flash": { displayName: "Gemini Flash", resolve: "opencode/gemini-3-flash" },
      "kimi-k2": { displayName: "Kimi K2", resolve: "opencode/kimi-k2.5" },
      "gpt-5-nano": { displayName: "GPT-5 Nano", resolve: "opencode/gpt-5-nano" },
      "mimo-v2-flash-free": {
        displayName: "MiMo V2 Flash",
        resolve: "opencode/mimo-v2-flash-free",
      },
      "minimax-m2.5-free": { displayName: "MiniMax M2.5", resolve: "opencode/minimax-m2.5-free" },
    },
  }),
  openrouter: provider({
    displayName: "OpenRouter",
    envVars: ["OPENROUTER_API_KEY"],
    models: {
      "claude-opus": {
        displayName: "Claude Opus",
        resolve: "openrouter/anthropic/claude-opus-4.6",
        recommended: true,
      },
      "claude-sonnet": {
        displayName: "Claude Sonnet",
        resolve: "openrouter/anthropic/claude-sonnet-4.6",
      },
      "claude-haiku": {
        displayName: "Claude Haiku",
        resolve: "openrouter/anthropic/claude-haiku-4.5",
      },
      "gpt-codex": { displayName: "GPT Codex", resolve: "openrouter/openai/gpt-5.3-codex" },
      "gpt-codex-mini": {
        displayName: "GPT Codex Mini",
        resolve: "openrouter/openai/gpt-5.1-codex-mini",
      },
      "gemini-pro": {
        displayName: "Gemini Pro",
        resolve: "openrouter/google/gemini-3.1-pro-preview",
      },
      "gemini-flash": {
        displayName: "Gemini Flash",
        resolve: "openrouter/google/gemini-3-flash-preview",
      },
      grok: { displayName: "Grok", resolve: "openrouter/x-ai/grok-4" },
      "deepseek-chat": {
        displayName: "DeepSeek Chat",
        resolve: "openrouter/deepseek/deepseek-chat-v3.1",
      },
      "kimi-k2": { displayName: "Kimi K2", resolve: "openrouter/moonshotai/kimi-k2.5" },
    },
  }),
} satisfies Record<string, ProviderConfig>;

export type ModelProvider = keyof typeof providers;

// ── slug parsing ───────────────────────────────────────────────────────────────

export function parseModel(slug: string): { provider: string; model: string } {
  const slashIdx = slug.indexOf("/");
  if (slashIdx === -1) {
    throw new Error(`invalid model slug "${slug}" — expected "provider/model"`);
  }
  return { provider: slug.slice(0, slashIdx), model: slug.slice(slashIdx + 1) };
}

export function getModelProvider(slug: string): string {
  return parseModel(slug).provider;
}

export function getModelEnvVars(slug: string): string[] {
  const p = getModelProvider(slug);
  return (providers as Record<string, ProviderConfig>)[p]?.envVars.slice() ?? [];
}

// ── derived flat list ──────────────────────────────────────────────────────────

export const modelAliases: ModelAlias[] = Object.entries(providers).flatMap(
  ([providerKey, config]) =>
    Object.entries(config.models).map(([modelId, def]) => ({
      slug: `${providerKey}/${modelId}`,
      provider: providerKey,
      displayName: def.displayName,
      resolve: def.resolve,
      recommended: def.recommended ?? false,
    }))
);

// ── resolution ─────────────────────────────────────────────────────────────────

/** resolve a model slug to its concrete models.dev specifier (e.g. "anthropic/claude-opus-4-6") */
export function resolveModelSlug(slug: string): string | undefined {
  return modelAliases.find((a) => a.slug === slug)?.resolve;
}

/** resolve a model slug to the CLI-ready model string (full models.dev specifier) */
export function resolveCliModel(slug: string): string | undefined {
  return resolveModelSlug(slug);
}