/**
 * REST route handlers for the OpenFinClaw dashboard HTTP server.
 */
import { readFileSync } from "node:fs";
import type { IncomingMessage, ServerResponse } from "node:http";
import { join } from "node:path";
import type { DatabaseSync } from "node:sqlite";
import { fileURLToPath } from "node:url";
import {
  queryActivityLog,
  queryAgentEvents,
  queryBacktestResults,
  queryPriceAlerts,
  queryScanHistory,
  queryStrategies,
} from "../db/repositories.js";

// Resolve path to web/index.html relative to this file's location
const WEB_DIR = join(fileURLToPath(import.meta.url), "..", "..", "..", "web");

function getIndexHtml(): string {
  return readFileSync(join(WEB_DIR, "index.html"), "utf8");
}

function parseQueryParam(url: string, name: string, fallback: number): number {
  try {
    const u = new URL(url, "http://localhost");
    const v = u.searchParams.get(name);
    const n = v != null ? parseInt(v, 10) : NaN;
    return Number.isFinite(n) && n >= 0 ? n : fallback;
  } catch {
    return fallback;
  }
}

function parseStringParam(url: string, name: string): string | undefined {
  try {
    const u = new URL(url, "http://localhost");
    return u.searchParams.get(name) ?? undefined;
  } catch {
    return undefined;
  }
}

function sendJson(res: ServerResponse, data: unknown): void {
  const body = JSON.stringify(data);
  res.writeHead(200, {
    "Content-Type": "application/json",
    "Content-Length": Buffer.byteLength(body),
    "Access-Control-Allow-Origin": "*",
  });
  res.end(body);
}

function sendHtml(res: ServerResponse, html: string): void {
  res.writeHead(200, { "Content-Type": "text/html; charset=utf-8" });
  res.end(html);
}

function send404(res: ServerResponse): void {
  res.writeHead(404, { "Content-Type": "text/plain" });
  res.end("Not found");
}

/**
 * Dispatch an incoming HTTP request to the appropriate handler.
 */
export function handleRoute(db: DatabaseSync, req: IncomingMessage, res: ServerResponse): void {
  const url = req.url ?? "/";
  const pathname = url.split("?")[0];

  // Dashboard HTML
  if (pathname === "/" || pathname === "/index.html") {
    try {
      sendHtml(res, getIndexHtml());
    } catch {
      res.writeHead(500);
      res.end("Failed to load dashboard HTML");
    }
    return;
  }

  if (pathname === "/api/activity-log") {
    const limit = parseQueryParam(url, "limit", 50);
    const offset = parseQueryParam(url, "offset", 0);
    sendJson(res, queryActivityLog(db, limit, offset));
    return;
  }

  if (pathname === "/api/agent-events") {
    const limit = parseQueryParam(url, "limit", 50);
    const offset = parseQueryParam(url, "offset", 0);
    sendJson(res, queryAgentEvents(db, limit, offset));
    return;
  }

  if (pathname === "/api/strategies") {
    sendJson(res, queryStrategies(db));
    return;
  }

  if (pathname === "/api/backtest-results") {
    const strategyId = parseStringParam(url, "strategy_id");
    sendJson(res, queryBacktestResults(db, strategyId));
    return;
  }

  if (pathname === "/api/scan-history") {
    const limit = parseQueryParam(url, "limit", 20);
    const offset = parseQueryParam(url, "offset", 0);
    const scanType = parseStringParam(url, "scan_type");
    sendJson(res, queryScanHistory(db, { scanType, limit, offset }));
    return;
  }

  if (pathname === "/api/price-alerts") {
    const limit = parseQueryParam(url, "limit", 50);
    const offset = parseQueryParam(url, "offset", 0);
    const strategyId = parseStringParam(url, "strategy_id");
    sendJson(res, queryPriceAlerts(db, { strategyId, limit, offset }));
    return;
  }

  send404(res);
}