/*
 * Amsterdam Web Communities System
 * Copyright (c) 2025-2026 Erbosoft Metaverse Design Solutions, All Rights Reserved
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * SPDX-License-Identifier: MPL-2.0
 */
// Package main contains the high-level Amsterdam logic.
package main

import (
	"errors"
	"fmt"
	"net/http"
	"time"

	"git.erbosoft.com/amy/amsterdam/config"
	"git.erbosoft.com/amy/amsterdam/ui"
	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"
	log "github.com/sirupsen/logrus"
	"golang.org/x/time/rate"
)

// EBUTTON is the standard error for an unknown button.
var EBUTTON error = errors.New("invalid or unknown button pressed")

// EINVAL is the standard error for an invalid parameter.
var EINVAL error = errors.New("invalid parameter to operation")

// ELOGIN is the standard error for not being logged in
var ELOGIN error = errors.New("you are not logged in")

// ENOPERM is the standard "not permitted" error message.
var ENOPERM *echo.HTTPError = echo.NewHTTPError(http.StatusForbidden, "you are not permitted to perform this operation")

// ENOACCESS is the standard "no access" error message.
var ENOACCESS *echo.HTTPError = echo.NewHTTPError(http.StatusForbidden, "you are not permitted to access this page")

// EPARAM is an error for no parameters being specified.
var EPARAM error = errors.New("no parameters specified")

/* NotImplPage is used for all TODO links, to show that something hasn't yet been implemented.
 * Parameters:
 *     ctxt - The AmContext for the request.
 * Returns:
 *     Command string dictating what to be rendered.
 *     Data as a parameter for the command string.
 */
func NotImplPage(ctxt ui.AmContext) (string, any) {
	ctxt.SetLeftMenu("top")
	ctxt.SetFrameTitle("Function Not Implemented")
	ctxt.VarMap().Set("path", ctxt.URLPath())
	return "framed", "notimpl.jet"
}

/* AmNotFoundHandler handles all paths that are "not found" in the application.
 * Parameters:
 *     ctxt - The AmContext for the request.
 * Returns:
 *     Command string dictating what to be rendered.
 *     Data as a parameter for the command string.
 */
func AmNotFoundHandler(ctxt ui.AmContext) (string, any) {
	log.Infof("-> AmNotFoundHandler on path %s", ctxt.URLPath())
	return "error", fmt.Errorf("Path not found: %s", ctxt.URLPath())
}

/* AmErrorHandler handles all the mundane HTTP errors generated by the Echo engine.
 * Parameters:
 *     err - The error to be handled.
 *     c - The Echo context error is being handled on.
 */
func AmErrorHandler(err error, c echo.Context) {
	log.Infof("-> AmErrorHandler on path %s", c.Request().URL.Path)
	if c.Response().Committed {
		return
	}
	cerr := ui.AmWithTempContext(c, func(ctxt ui.AmContext) (string, any) {
		return "error", err
	})
	if cerr != nil {
		log.Errorf("Error rendering error (%v): %v", err, cerr)
	}
}

// rateLimitErrorHandler is called if there's an error getting the identifier for a connection (unlikely).
func rateLimitErrorHandler(c echo.Context, err error) error {
	return ui.AmWithTempContext(c, func(ctxt ui.AmContext) (string, any) {
		return "error", err
	})
}

// rateLimitDenyHandler is called if the rate limit is exceeded by a connection.
func rateLimitDenyHandler(c echo.Context, identifier string, err error) error {
	return ui.AmWithTempContext(c, func(ctxt ui.AmContext) (string, any) {
		ctxt.VarMap().Set("identifier", identifier)
		return "ratelimit", err
	})
}

// AmSetupRateLimiter sets up the rate-limiting middleware.
func AmSetupRateLimiter() echo.MiddlewareFunc {
	rcfg := middleware.RateLimiterMemoryStoreConfig{
		Rate:      rate.Limit(config.GlobalConfig.Site.RateLimit.Rate),
		Burst:     config.GlobalConfig.Site.RateLimit.Burst,
		ExpiresIn: time.Duration(config.GlobalConfig.Site.RateLimit.ExpireMinutes) * time.Minute,
	}
	cfg := middleware.RateLimiterConfig{
		Store:        middleware.NewRateLimiterMemoryStoreWithConfig(rcfg),
		ErrorHandler: rateLimitErrorHandler,
		DenyHandler:  rateLimitDenyHandler,
	}
	return middleware.RateLimiterWithConfig(cfg)
}