// Copyright 2023 wanderer <a_mirre at utb dot cz>
// SPDX-License-Identifier: AGPL-3.0-only

package app

import (
	"encoding/hex"
	"net/http"
	"regexp"

	"github.com/gorilla/sessions"
	"github.com/labstack/echo-contrib/session"
	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"
	"golang.org/x/exp/slog"
	"golang.org/x/time/rate"
)

// SetServerSettings sets up the main Echo instance and panics on err.
func (a *App) SetServerSettings() {
	e := a.E()

	e.HideBanner = true

	if a.setting.DefaultLoggerSkipAssets() {
		re := regexp.MustCompile("^/(assets|static)(.*)|favicon.ico")
		lC := middleware.DefaultLoggerConfig

		lC.Skipper = func(c echo.Context) bool {
			r := c.Request().URL.Path

			slog.Debug("logger skipper", "path", r)

			return re.MatchString(r)
		}
		e.Use(middleware.LoggerWithConfig(lC))
	} else {
		e.Use(middleware.Logger())
	}

	// e.Use(middleware.LoggerWithConfig(
	// middleware.LoggerConfig{
	// Format: `{"time":"${time_rfc3339_nano}","id":"${id}","remote_ip":"${remote_ip}",` +
	// `"host":"${host}","method":"${method}","uri":"${uri}","user_agent":"${user_agent}",` +
	// `"status":${status},"error":"${error}","latency":${latency},"latency_human":"${latency_human}"` +
	// `,"bytes_in":${bytes_in},"bytes_out":${bytes_out}}` + "\n",
	// CustomTimeFormat: "2006-01-02 15:04:05.00000",
	// },
	// ))
	// logger := zerolog.New(os.Stdout)
	// e.Use(middleware.RequestLoggerWithConfig(middleware.RequestLoggerConfig{
	// LogURI:    true,
	// LogStatus: true,
	// LogValuesFunc: func(c echo.Context, v middleware.RequestLoggerValues) error {
	// logger.Info().
	// Str("URI", v.URI).
	// Int("status", v.Status).
	// Msg("request")
	//
	// return nil
	// },
	// }))

	// TODO: make this configurable.
	e.Server.WriteTimeout = a.setting.DefaultServerWriteTimeout()
	e.Server.ReadHeaderTimeout = a.setting.DefaultServerReadHeaderTimeout()

	if a.setting.HTTPRateLimitEnabled() {
		limit := rate.Limit(a.setting.HTTPRateLimit())

		e.Use(middleware.RateLimiter(
			middleware.NewRateLimiterMemoryStore(limit),
		))
	}

	// TODO: add check for prometheus config setting.
	// if true {
	// // import "github.com/labstack/echo-contrib/prometheus"
	// p := prometheus.NewPrometheus("echo", nil)
	// p.Use(e)
	// }

	e.Use(middleware.Recover())

	var (
		store      *sessions.CookieStore
		authSecret []byte
		encrSecret []byte
	)

	if a.setting.SessionAuthIsHex() {
		b, err := hex.DecodeString(a.setting.SessionCookieAuthSecret())
		if err != nil {
			panic(err)
		}

		authSecret = b
	}

	if a.setting.SessionEncrIsHex() {
		b, err := hex.DecodeString(a.setting.SessionCookieEncrSecret())
		if err != nil {
			panic(err)
		}

		encrSecret = b
	}

	switch {
	case authSecret != nil && encrSecret != nil:
		store = sessions.NewCookieStore(
			authSecret,
			encrSecret,
		)
	case authSecret != nil && encrSecret == nil:
		store = sessions.NewCookieStore(
			authSecret,
			[]byte(a.setting.SessionCookieEncrSecret()),
		)
	case authSecret == nil && encrSecret != nil:
		store = sessions.NewCookieStore(
			[]byte(a.setting.SessionCookieAuthSecret()),
			encrSecret,
		)
	case authSecret == nil && encrSecret == nil:
		store = sessions.NewCookieStore(
			[]byte(a.setting.SessionCookieAuthSecret()),
			[]byte(a.setting.SessionCookieEncrSecret()),
		)
	}

	store.Options.Path = "/"
	store.Options.Domain = a.setting.HTTPDomain()
	store.Options.HttpOnly = true
	store.Options.SameSite = http.SameSiteStrictMode
	store.Options.Secure = a.setting.HTTPSecure()
	store.Options.MaxAge = a.setting.SessionMaxAge()

	if a.setting.HTTPSecure() {
		// https://www.sjoerdlangkemper.nl/2017/02/09/cookie-prefixes/
		// https://scotthelme.co.uk/tough-cookies/
		// https://check-your-website.server-daten.de/prefix-cookies.html
		store.Options.Domain = "__Host-" + store.Options.Domain
	}

	e.Use(session.Middleware(store))

	e.Use(middleware.Secure())

	if a.setting.HTTPGzipEnabled() {
		e.Use(middleware.GzipWithConfig(middleware.GzipConfig{
			Level: a.setting.HTTPGzipLevel(),
		}))
	}
}

func (a *App) csrfConfig() echo.MiddlewareFunc {
	csrfCookieName := "pcmt_csrf"
	if a.setting.HTTPSecure() {
		// https://www.sjoerdlangkemper.nl/2017/02/09/cookie-prefixes/
		// https://scotthelme.co.uk/tough-cookies/
		// https://check-your-website.server-daten.de/prefix-cookies.html
		csrfCookieName = "__Host-" + csrfCookieName
	}

	return middleware.CSRFWithConfig(middleware.CSRFConfig{
		TokenLookup: "cookie:" + csrfCookieName +
			",form:csrf,header:" + echo.HeaderXCSRFToken,
		CookieName: csrfCookieName,
		ContextKey: "csrf",
		// CookieDomain:   "localhost",
		CookieSecure:   a.setting.HTTPSecure(),
		CookieHTTPOnly: true,
		CookieSameSite: http.SameSiteStrictMode,
		CookieMaxAge:   a.setting.SessionMaxAge(),
		CookiePath:     "/",
	},
	)
}