// Package webpublic contains the public webserver
// which provides the primary and only intended access point
// for interacting with the system.
//
// # Sections
//
// - Frontend: Serves the various web frontend versions
//   - Main: The original Linstrom specific frontend
//   - NoJs: An entirely serverside rendered frontend, no JS included
//   - Custom: Custom frontend files will be served here
//
// - API: Endpoints for the actual interactions
//   - Frontend: The API used by the main frontend
//   - Masto: Mastodon compatible adapter for internal structures
//   - ActivityPub: For integration with the Fediverse via ActivityPub
//   - Linstrom-RPC: For Linstrom to Linstrom server communication
//
// # Guarantees
//
//   - The Masto and ActivityPub API will remain stable
//   - Frontend API might change, but the intended consumer (Main frontend)
//     will always be up to date with the changes
//   - Linstrom-RPC API is versioned and will keep
//     a few versions of backwards compatibility
//
// TODO: Decide how long the Linstrom-RPC API will remain backwards compatible
package webpublic

import (
	"context"
	"io/fs"
	"net/http"

	webutils "git.mstar.dev/mstar/goutils/http"
	"github.com/quic-go/quic-go/http3"
	"github.com/rs/zerolog/log"

	"git.mstar.dev/mstar/linstrom/auth-new"
	"git.mstar.dev/mstar/linstrom/config"
	"git.mstar.dev/mstar/linstrom/web/public/api"
	webmiddleware "git.mstar.dev/mstar/linstrom/web/public/middleware"
)

type Server struct {
	server     *http.Server
	quicServer *http3.Server
}

func New(addr string, duckImg *string, duckFs fs.FS) *Server {
	handler := http.NewServeMux()
	handler.Handle("/api/", http.StripPrefix("/api", api.BuildApiRouter()))
	handler.HandleFunc("GET /.well-known/webfinger", api.WellKnownWebfinger)
	handler.HandleFunc("GET /.well-known/nodeinfo", api.NodeInfoOverview)
	handler.HandleFunc("GET /nodeinfo/2.1", api.NodeInfo21)
	handler.HandleFunc("GET /nodeinfo/2.0", api.NodeInfo20)
	handler.HandleFunc("GET /errors/{name}", errorTypeHandler)
	handler.HandleFunc("GET /default-image", buildServeDefaultImage(duckImg, duckFs))
	handler.HandleFunc("GET /default-image.webp", buildServeDefaultImage(duckImg, duckFs))
	rootHandler := webutils.ChainMiddlewares(
		handler,
		webutils.BuildLoggingMiddleware(
			true,
			[]string{"/assets"},
			map[string]string{"server": "public"},
		),
		webmiddleware.AppendFullPathMiddleware,
		webmiddleware.TraceRequestInfoMiddleware,
		webmiddleware.AddUpgradeHeader,
	)
	server := http.Server{
		Handler: rootHandler,
		Addr:    addr,
	}
	quicServer := http3.Server{
		Handler: rootHandler,
		Addr:    addr,
	}
	if config.GlobalConfig.General.PublicPort != nil {
		quicServer.Port = *config.GlobalConfig.General.PublicPort
	}
	return &Server{server: &server, quicServer: &quicServer}
}

func (s *Server) Start() error {
	if config.GlobalConfig.SSL.HandleSSL {
		certFile, keyFile, err := auth.TlsFromConfig()
		if err != nil {
			return err
		}
		if config.GlobalConfig.Experimental.Http3Support {
			errChan := make(chan error, 2)
			go func() {
				errChan <- s.server.ListenAndServeTLS(certFile, keyFile)
			}()
			go func() {
				errChan <- s.quicServer.ListenAndServeTLS(certFile, keyFile)
			}()

			err := <-errChan
			if err != nil && err != http.ErrServerClosed {
				return err
			}
			// Always gets two values back on the channel since both servers are running
			err = <-errChan
			if err != nil && err != http.ErrServerClosed {
				return err
			}
			return nil
		} else {
			return s.server.ListenAndServeTLS(certFile, keyFile)
		}
	} else {
		// But refuse http3 support here, since it doesn't work without tls
		return s.server.ListenAndServe()
	}
}

func (s *Server) Stop() error {
	if config.GlobalConfig.SSL.HandleSSL && config.GlobalConfig.Experimental.Http3Support {
		errChan := make(chan error, 2)
		go func() {
			log.Debug().Msg("Stopping tcp server")
			errChan <- s.server.Shutdown(context.Background())
			log.Debug().Msg("Tcp server stopped")
		}()
		go func() {
			log.Debug().Msg("Stopping udp server")
			errChan <- s.quicServer.Shutdown(context.Background())
			log.Debug().Msg("Udp server stopped")
		}()

		err := <-errChan
		if err != nil && err != http.ErrServerClosed {
			return err
		}
		// Always gets two values back on the channel since both servers are running
		err = <-errChan
		if err != nil && err != http.ErrServerClosed {
			return err
		}
		return nil
	} else {
		return s.server.Shutdown(context.Background())
	}
}

func buildServeDefaultImage(
	duckImg *string,
	duckFs fs.FS,
) func(w http.ResponseWriter, r *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		http.ServeFileFS(w, r, duckFs, "duck.webp")
		// w.Header().Add("Content-Type", "image/webp")
		// w.Header().Add("Content-Disposition", "attachment; filename=\"duck.webp\"")
		// fmt.Fprint(w, *duckImg)
	}
}