package server

import (
	"fmt"
	"log/slog"
	"net"
	"net/http"
	"strings"

	"ddc/internal/auth"
)

type loginRequest struct {
	Username string `json:"username"`
	Password string `json:"password"`
}

type sessionResponse struct {
	Authenticated bool `json:"authenticated"`
}

func (server *Server) handleLogin(writer http.ResponseWriter, request *http.Request) {
	client := server.clientAddress(request)
	if !server.limiter.Allowed(client) {
		slog.Warn("login blocked after too many failures", "client", client, "request_id", requestIDFrom(request))
		writeError(writer, http.StatusTooManyRequests, "too many failed attempts, try again later")
		return
	}

	var body loginRequest
	if !decodeBody(writer, request, &body) {
		return
	}
	if !auth.CredentialsMatch(server.settings.Username, server.settings.Password, body.Username, body.Password) {
		server.limiter.RecordFailure(client)
		slog.Warn("login failed", "client", client, "username", body.Username, "request_id", requestIDFrom(request))
		writeError(writer, http.StatusUnauthorized, "invalid username or password")
		return
	}

	server.limiter.Reset(client)
	token, err := server.sessions.Create()
	if err != nil {
		writeFailure(writer, request, fmt.Errorf("could not create session: %w", err))
		return
	}
	slog.Info("login succeeded", "client", client, "request_id", requestIDFrom(request))
	http.SetCookie(writer, server.sessionCookie(token, int(server.settings.SessionTTL.Seconds())))
	writeJSON(writer, http.StatusOK, sessionResponse{Authenticated: true})
}

func (server *Server) handleLogout(writer http.ResponseWriter, request *http.Request) {
	if cookie, err := request.Cookie(sessionCookieName); err == nil {
		server.sessions.Delete(cookie.Value)
	}
	http.SetCookie(writer, server.sessionCookie("", -1))
	writeJSON(writer, http.StatusOK, sessionResponse{Authenticated: false})
}

func (server *Server) handleSession(writer http.ResponseWriter, request *http.Request) {
	writeJSON(writer, http.StatusOK, sessionResponse{Authenticated: server.authenticated(request)})
}

func (server *Server) sessionCookie(value string, maxAge int) *http.Cookie {
	return &http.Cookie{
		Name:     sessionCookieName,
		Value:    value,
		Path:     "/",
		MaxAge:   maxAge,
		HttpOnly: true,
		Secure:   server.settings.CookieSecure,
		SameSite: http.SameSiteStrictMode,
	}
}

func (server *Server) clientAddress(request *http.Request) string {
	if server.settings.TrustProxyHeaders {
		if realIP := strings.TrimSpace(request.Header.Get("X-Real-IP")); realIP != "" {
			return realIP
		}
	}
	host, _, err := net.SplitHostPort(request.RemoteAddr)
	if err != nil {
		return request.RemoteAddr
	}
	return host
}