/**
 * Configuration loading.
 *
 * The adapter accepts config from two sources:
 *   1. Environment variables (loaded from process.env at module init)
 *   2. A plain object passed in (e.g. from Paperclip's adapter config UI)
 *
 * For env-var resolution, keys named `*_ENV` are treated as env-var name
 * pointers (e.g. `MINIMAX_API_KEY_ENV=MINIMAX_PROD_KEY` → reads the
 * MINIMAX_PROD_KEY env var instead). This is how Paperclip's secret
 * binding works.
 */
import { z } from "zod";
import type { AdapterConfig } from "./types.js";

export type ResolvedConfig = AdapterConfig;

export const configSchema = z.object({
  apiKey: z.string().default(""),
  baseUrl: z.string().url().default("https://api.minimax.chat/v1"),
  model: z.string().min(1).default("MiniMax-M3"),
  priceInputPer1M: z.number().nonnegative().default(1.0),
  priceOutputPer1M: z.number().nonnegative().default(3.0),
  paperclipApiKey: z.string().default(""),
  paperclipApiUrl: z.string().url().default("http://localhost:3100"),
  maxToolCallsPerTurn: z.number().int().positive().default(10),
  maxTurns: z.number().int().positive().default(8),
  enableStreaming: z.boolean().default(true),
  skillsDir: z.string().default(""),
  approvalGated: z.boolean().default(true),
  workspacePath: z.string().default(""),
});

/**
 * Resolve a string of the form `name` or `name_ENV=OTHER_NAME` to an
 * actual env var value. Falls back to the original string if neither
 * the *key or the *name resolves.
 */
function resolveEnv(input: string | undefined, fallback = ""): string {
  if (!input) return fallback;
  const m = input.match(/^(.*)_ENV=(.*)$/);
  if (m) {
    const [, , otherName] = m;
    const v = process.env[otherName];
    return v && v.length > 0 ? v : fallback;
  }
  const v = process.env[input];
  return v && v.length > 0 ? v : fallback;
}

function num(input: string | undefined, fallback: number): number {
  if (!input) return fallback;
  const n = Number(input);
  return Number.isFinite(n) ? n : fallback;
}

function bool(input: string | undefined, fallback: boolean): boolean {
  if (!input) return fallback;
  return input === "1" || input.toLowerCase() === "true";
}

/**
 * Build a full AdapterConfig from (a) the env, (b) any explicit
 * overrides. `overrides` win.
 */
export function loadConfig(overrides: Partial<AdapterConfig> = {}): AdapterConfig {
  // Try the explicit env var first, fall back to the friendly name,
  // then to the Paperclip convention of `*_ENV` pointing at a stored secret.
  const apiKey = resolveEnv(overrides.apiKey) ||
    resolveEnv(process.env.MINIMAX_API_KEY) ||
    resolveEnv(process.env.MINIMAX_API_KEY_ENV);
  const paperclipApiKey = resolveEnv(overrides.paperclipApiKey) ||
    process.env.PAPERCLIP_API_KEY ||
    "";

  const merged: AdapterConfig = {
    apiKey,
    baseUrl: overrides.baseUrl ?? process.env.MINIMAX_BASE_URL ?? "https://api.minimax.chat/v1",
    model: overrides.model ?? process.env.MINIMAX_MODEL ?? "MiniMax-M3",
    priceInputPer1M: overrides.priceInputPer1M ?? num(process.env.MINIMAX_PRICE_INPUT_PER_1M, 1.0),
    priceOutputPer1M: overrides.priceOutputPer1M ?? num(process.env.MINIMAX_PRICE_OUTPUT_PER_1M, 3.0),
    paperclipApiKey,
    paperclipApiUrl: overrides.paperclipApiUrl ?? process.env.PAPERCLIP_API_URL ?? "http://localhost:3100",
    maxToolCallsPerTurn: overrides.maxToolCallsPerTurn ?? num(process.env.MAX_TOOL_CALLS_PER_TURN, 10),
    maxTurns: overrides.maxTurns ?? num(process.env.MAX_TURNS, 8),
    enableStreaming: overrides.enableStreaming ?? bool(process.env.ENABLE_STREAMING, true),
    skillsDir: overrides.skillsDir ?? process.env.SKILLS_DIR ?? "",
    approvalGated: overrides.approvalGated ?? bool(process.env.MINIMAX_APPROVAL_GATED, true),
    workspacePath: overrides.workspacePath ?? process.env.MINIMAX_WORKSPACE_PATH ?? "",
  };

  // Validate. Throws ZodError on bad input — we want the loudest possible
  // failure for misconfiguration since silent degradation in an agent
  // heartbeat is the worst possible failure mode.
  return configSchema.parse(merged);
}