#include "RequireAuthMiddleware.h"
#include "HTTPContext.h"
#include "Web.h"
#include "Game.h"
#include "Logger.h"

namespace {
	bool IsApiRequest(const HTTPContext& context) {
		return context.path.starts_with("/api/");
	}

	// What an account that still has to set up two-factor login may reach: signing in and out, its own account
	bool AllowedBeforeTwoFactor(const HTTPContext& context) {
		const auto& path = context.path;
		return path.starts_with("/api/auth/") || path.starts_with("/api/account/") || path == "/account" || path == "/api/status" ||
			path == "/accounts/" + std::to_string(context.accountId) || path == "/api/accounts/" + std::to_string(context.accountId) ||
			path.starts_with("/js/") || path.starts_with("/css/") || path == "/favicon.ico";
	}

	std::function<bool(uint8_t)> g_ApiAccessAllowed;
	std::function<void(const HTTPContext&, HTTPReply&)> g_ForbiddenPage;

	bool IsSafeMethod(const HTTPContext& context) {
		return context.method == "GET" || context.method == "HEAD" || context.method == "OPTIONS";
	}
}

void RequireAuthMiddleware::SetApiAccessCheck(std::function<bool(uint8_t gmLevel)> check) {
	g_ApiAccessAllowed = std::move(check);
}

void RequireAuthMiddleware::SetForbiddenPage(std::function<void(const HTTPContext& context, HTTPReply& reply)> render) {
	g_ForbiddenPage = std::move(render);
}

RequireAuthMiddleware::RequireAuthMiddleware(uint8_t minGmLevel) : requiredLevel([minGmLevel] { return minGmLevel; }) {}

RequireAuthMiddleware::RequireAuthMiddleware(std::function<uint8_t()> requiredLevel) : requiredLevel(std::move(requiredLevel)) {}

bool RequireAuthMiddleware::Process(HTTPContext& context, HTTPReply& reply) {
	if (!context.isAuthenticated) {
		LOG_DEBUG("Unauthorized access attempt to %s from %s", context.path.c_str(), context.clientIP.c_str());
		if (IsApiRequest(context)) {
			reply.status = eHTTPStatusCode::UNAUTHORIZED;
			reply.message = "{\"success\":false,\"error\":\"Authentication required\"}";
			reply.contentType = eContentType::APPLICATION_JSON;
		} else {
			reply.status = eHTTPStatusCode::FOUND;
			reply.message = "";
			reply.location = "/login";
			reply.contentType = eContentType::TEXT_HTML;
		}
		return false;
	}

	// Cookies are sent automatically by the browser, so state-changing requests authenticated by
	// cookie must also carry a header a cross-site form cannot set. Bearer-token clients are exempt.
	const auto authSource = context.userData.find("auth_source");
	if (!IsSafeMethod(context) && authSource != context.userData.end() && authSource->second == "cookie" &&
		context.GetHeader("X-Requested-With").empty()) {
		LOG("Rejected cookie-authenticated %s %s without X-Requested-With (possible CSRF) from %s",
			context.method.c_str(), context.path.c_str(), context.clientIP.c_str());
		reply.status = eHTTPStatusCode::FORBIDDEN;
		reply.message = "{\"success\":false,\"error\":\"Missing X-Requested-With header\"}";
		reply.contentType = eContentType::APPLICATION_JSON;
		return false;
	}

	// A token in the Authorization header is API use, which a GM level may not be allowed
	if (authSource != context.userData.end() && authSource->second == "header" && g_ApiAccessAllowed && !g_ApiAccessAllowed(context.gmLevel)) {
		reply.status = eHTTPStatusCode::FORBIDDEN;
		reply.message = "{\"success\":false,\"error\":\"API access isn't allowed for your account\"}";
		reply.contentType = eContentType::APPLICATION_JSON;
		return false;
	}

	if (context.userData.contains("needs_2fa") && !AllowedBeforeTwoFactor(context)) {
		if (IsApiRequest(context)) {
			reply.status = eHTTPStatusCode::FORBIDDEN;
			reply.message = "{\"success\":false,\"error\":\"Set up two-factor login on your account page first\",\"code\":\"2fa_required\"}";
			reply.contentType = eContentType::APPLICATION_JSON;
		} else {
			reply.status = eHTTPStatusCode::FOUND;
			reply.message = "";
			reply.location = "/accounts/" + std::to_string(context.accountId) + "#two-factor";
			reply.contentType = eContentType::TEXT_HTML;
		}
		return false;
	}

	const auto minGmLevel = requiredLevel();
	if (context.gmLevel < minGmLevel) {
		LOG_DEBUG("Forbidden access attempt by user %s (GM level %d < %d required) to %s from %s",
			context.authenticatedUser.c_str(), context.gmLevel, minGmLevel,
			context.path.c_str(), context.clientIP.c_str());
		// A page opened in the browser gets the dashboard's error page rather than raw JSON
		if (!IsApiRequest(context) && g_ForbiddenPage) {
			g_ForbiddenPage(context, reply);
			reply.status = eHTTPStatusCode::FORBIDDEN;
			return false;
		}
		reply.status = eHTTPStatusCode::FORBIDDEN;
		reply.message = "{\"success\":false,\"error\":\"Insufficient permissions\"}";
		reply.contentType = eContentType::APPLICATION_JSON;
		return false;
	}

	return true;
}