import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
import { readFileSync, existsSync } from "node:fs";
import { join } from "node:path";

const BASE_URL = "http://exacode-chat.lge.com/v1";

// The EXACODE gateway routes requests by the `X-Title` header.
//   - "EXACODE Agent Roo" -> the official VS Code extension route; gated by a
//     client-version check (blocks curl/SDKs/outdated builds).
//   - "EXACODE SWE(API)"  -> the API-client route; the intended tier for
//     programmatic access. Requires an SWE(API)-scoped bearer token, which
//   lives in `.env` as EXACODE_API_KEY (different from the Roo Code JWT).
//
// `X-Model` echoes the requested model id (redundant -- it also travels in the
// request body -- but the official example sets it as a default header).
const X_TITLE = "EXACODE SWE(API)";

// pi does not auto-load `.env`, so populate process.env ourselves at startup.
// Real environment variables take precedence over the file.
function loadDotEnv(file: string) {
  if (!existsSync(file)) return;
  const text = readFileSync(file, "utf8");
  for (const rawLine of text.split(/\r?\n/)) {
    const line = rawLine.trim();
    if (!line || line.startsWith("#")) continue;
    const eq = line.indexOf("=");
    if (eq < 0) continue;
    const key = line.slice(0, eq).trim();
    let value = line.slice(eq + 1).trim();
    if (
      (value.startsWith('"') && value.endsWith('"')) ||
      (value.startsWith("'") && value.endsWith("'"))
    ) {
      value = value.slice(1, -1);
    }
    if (key && process.env[key] === undefined) {
      process.env[key] = value;
    }
  }
}

loadDotEnv(join(process.cwd(), ".env"));

const MODELS = [
  {
    id: "Chat-EXACODE-A",
    name: "Chat-EXACODE-A (EXACODE 3.5)",
    reasoning: true,
    input: ["text"] as const,
    cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
    contextWindow: 131072,
    maxTokens: 8192,
    headers: { "X-Model": "Chat-EXACODE-A" },
  },
];

export default function (pi: ExtensionAPI) {
  pi.registerProvider("exacode", {
    name: "exacode",
    baseUrl: BASE_URL,
    apiKey: "$EXACODE_API_KEY",
    authHeader: true,
    api: "openai-completions",
    headers: {
      "X-Title": X_TITLE,
    },
    models: MODELS,
  });
}