import { NextRequest, NextResponse } from "next/server";

const API_BASE = process.env.NEXT_PUBLIC_API_URL || "http://localhost:8888";

// #region agent log
function debugLog(hypothesisId: string, message: string, data: Record<string, unknown>) {
  fetch("http://localhost:7687/ingest/ee56ea93-ad22-4673-ab77-595d83a9b3c5", {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "X-Debug-Session-Id": "6b638a",
    },
    body: JSON.stringify({
      sessionId: "6b638a",
      runId: "login-400-debug",
      hypothesisId,
      location: "frontend/app/api/[...path]/route.ts:debugLog",
      message,
      data,
      timestamp: Date.now(),
    }),
  }).catch(() => {});
}
// #endregion

export async function GET(req: NextRequest, ctx: { params: Promise<{ path: string[] }> }) {
  return proxyRequest(req, ctx);
}

export async function POST(req: NextRequest, ctx: { params: Promise<{ path: string[] }> }) {
  return proxyRequest(req, ctx);
}

export async function PUT(req: NextRequest, ctx: { params: Promise<{ path: string[] }> }) {
  return proxyRequest(req, ctx);
}

export async function PATCH(req: NextRequest, ctx: { params: Promise<{ path: string[] }> }) {
  return proxyRequest(req, ctx);
}

export async function DELETE(req: NextRequest, ctx: { params: Promise<{ path: string[] }> }) {
  return proxyRequest(req, ctx);
}

async function proxyRequest(
  req: NextRequest,
  ctx: { params: Promise<{ path: string[] }> }
) {
  const { path } = await ctx.params;
  const search = req.nextUrl.search || "";
  const proxiedPathRaw = req.nextUrl.pathname.replace(/^\/api\//, "");
  const normalizedPathRaw = proxiedPathRaw.startsWith("api/")
    ? proxiedPathRaw
    : `api/${proxiedPathRaw}`;
  const proxiedPath = normalizedPathRaw.endsWith("/") ? normalizedPathRaw : `${normalizedPathRaw}/`;
  const target = `${API_BASE}/${proxiedPath}${search}`;
  // #region agent log
  debugLog("H1_H2_H3", "proxy_request_start", {
    method: req.method,
    path,
    proxiedPath,
    originalPathname: req.nextUrl.pathname,
    search,
    apiBase: API_BASE,
    target,
  });
  // #endregion

  const headers = new Headers(req.headers);
  headers.delete("host");
  headers.delete("content-length");

  const hasBody = !["GET", "HEAD"].includes(req.method);
  const contentType = headers.get("content-type");
  const isMultipart = (contentType || "").toLowerCase().includes("multipart/form-data");
  let clonedBodyText = "";
  let requestBodyLength = 0;
  let requestBodyJsonKeys: string[] = [];
  let requestBodyReadError: string | null = null;

  if (hasBody && !isMultipart) {
    try {
      clonedBodyText = await req.clone().text();
      requestBodyLength = clonedBodyText.length;
      if (contentType?.includes("application/json")) {
        const parsed = JSON.parse(clonedBodyText || "{}");
        if (parsed && typeof parsed === "object" && !Array.isArray(parsed)) {
          requestBodyJsonKeys = Object.keys(parsed).sort();
        }
      }
    } catch (error) {
      requestBodyReadError = error instanceof Error ? error.message : "unknown_error";
    }
  }
  // #region agent log
  debugLog("H1_H3_H4", "proxy_request_body_probe", {
    method: req.method,
    target,
    hasBody,
    isMultipart,
    contentType,
    requestBodyLength,
    requestBodyJsonKeys,
    requestBodyReadError,
    hasUsernameKey: requestBodyJsonKeys.includes("username"),
    hasPasswordKey: requestBodyJsonKeys.includes("password"),
  });
  // #endregion

  const init: RequestInit & { duplex?: "half" } = {
    method: req.method,
    headers,
    cache: "no-store",
  };

  if (hasBody) {
    if (isMultipart) {
      // Multipart precisa seguir como stream para preservar boundary e arquivos.
      init.body = req.body;
      init.duplex = "half";
      debugLog("H9", "proxy_request_forward_mode", {
        method: req.method,
        target,
        forwardMode: "stream_multipart",
        contentType,
      });
    } else {
      // JSON/urlencoded segue buffer textual para evitar perda de stream no proxy.
      init.body = clonedBodyText;
      debugLog("H9", "proxy_request_forward_mode", {
        method: req.method,
        target,
        forwardMode: "buffered_text",
        forwardedBodyLength: clonedBodyText.length,
        contentType,
      });
    }
  }

  let res: Response;
  try {
    res = await fetch(target, init);
  } catch (error) {
    // #region agent log
    debugLog("H2", "proxy_request_fetch_exception", {
      target,
      error: error instanceof Error ? error.message : "unknown_error",
    });
    // #endregion
    return NextResponse.json({ message: "Falha de conexão no proxy." }, { status: 502 });
  }
  // #region agent log
  debugLog("H5", "proxy_request_first_attempt_done", {
    target,
    status: res.status,
    needsTrailingSlashRetry: res.status === 404 && !target.endsWith("/"),
  });
  // #endregion

  if (res.status === 404 && !target.endsWith("/")) {
    const targetWithSlash = `${target}/`;
    // #region agent log
    debugLog("H5", "proxy_request_retry_with_trailing_slash", {
      from: target,
      to: targetWithSlash,
    });
    // #endregion
    try {
      const retried = await fetch(targetWithSlash, init);
      // #region agent log
      debugLog("H5", "proxy_request_retry_response", {
        targetWithSlash,
        status: retried.status,
        statusText: retried.statusText,
      });
      // #endregion
      res = retried;
    } catch (error) {
      // #region agent log
      debugLog("H5", "proxy_request_retry_exception", {
        targetWithSlash,
        error: error instanceof Error ? error.message : "unknown_error",
      });
      // #endregion
    }
  }
  // #region agent log
  debugLog("H1_H3", "proxy_request_response", {
    target,
    status: res.status,
    statusText: res.statusText,
  });
  // #endregion
  if (res.status >= 400) {
    let responsePreview = "";
    try {
      responsePreview = (await res.clone().text()).slice(0, 300);
    } catch {
      responsePreview = "unreadable_response_body";
    }
    // #region agent log
    debugLog("H2_H4", "proxy_request_error_response_preview", {
      target,
      status: res.status,
      statusText: res.statusText,
      responsePreview,
    });
    // #endregion
  }

  const responseHeaders = new Headers();
  res.headers.forEach((value, key) => {
    responseHeaders.set(key, value);
  });

  return new NextResponse(res.body, {
    status: res.status,
    statusText: res.statusText,
    headers: responseHeaders,
  });
}