import { DEFAULT_MODEL, DEFAULT_PROVIDER } from "../../agents/defaults.js";
import {
  buildModelAliasIndex,
  modelKey,
  parseModelRef,
  resolveModelRefFromString,
} from "../../agents/model-selection.js";
import {
  type ClawdbotConfig,
  readConfigFileSnapshot,
  writeConfigFile,
} from "../../config/config.js";

export const ensureFlagCompatibility = (opts: {
  json?: boolean;
  plain?: boolean;
}) => {
  if (opts.json && opts.plain) {
    throw new Error("Choose either --json or --plain, not both.");
  }
};

export const formatTokenK = (value?: number | null) => {
  if (!value || !Number.isFinite(value)) return "-";
  if (value < 1024) return `${Math.round(value)}`;
  return `${Math.round(value / 1024)}k`;
};

export const formatMs = (value?: number | null) => {
  if (value === null || value === undefined) return "-";
  if (!Number.isFinite(value)) return "-";
  if (value < 1000) return `${Math.round(value)}ms`;
  return `${Math.round(value / 100) / 10}s`;
};

export async function updateConfig(
  mutator: (cfg: ClawdbotConfig) => ClawdbotConfig,
): Promise<ClawdbotConfig> {
  const snapshot = await readConfigFileSnapshot();
  if (!snapshot.valid) {
    const issues = snapshot.issues
      .map((issue) => `- ${issue.path}: ${issue.message}`)
      .join("\n");
    throw new Error(`Invalid config at ${snapshot.path}\n${issues}`);
  }
  const next = mutator(snapshot.config);
  await writeConfigFile(next);
  return next;
}

export function resolveModelTarget(params: {
  raw: string;
  cfg: ClawdbotConfig;
}): { provider: string; model: string } {
  const aliasIndex = buildModelAliasIndex({
    cfg: params.cfg,
    defaultProvider: DEFAULT_PROVIDER,
  });
  const resolved = resolveModelRefFromString({
    raw: params.raw,
    defaultProvider: DEFAULT_PROVIDER,
    aliasIndex,
  });
  if (!resolved) {
    throw new Error(`Invalid model reference: ${params.raw}`);
  }
  return resolved.ref;
}

export function buildAllowlistSet(cfg: ClawdbotConfig): Set<string> {
  const allowed = new Set<string>();
  for (const raw of cfg.agent?.allowedModels ?? []) {
    const parsed = parseModelRef(String(raw ?? ""), DEFAULT_PROVIDER);
    if (!parsed) continue;
    allowed.add(modelKey(parsed.provider, parsed.model));
  }
  return allowed;
}

export function normalizeAlias(alias: string): string {
  const trimmed = alias.trim();
  if (!trimmed) throw new Error("Alias cannot be empty.");
  if (!/^[A-Za-z0-9_.:-]+$/.test(trimmed)) {
    throw new Error(
      "Alias must use letters, numbers, dots, underscores, colons, or dashes.",
    );
  }
  return trimmed;
}

export { modelKey };
export { DEFAULT_MODEL, DEFAULT_PROVIDER };