package webserver

import (
	"net/http"
	"strings"

	"github.com/go-chi/chi/v5"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

func (ws *WebServer) handleUser(w http.ResponseWriter, r *http.Request) {
	info := tokenInfoFromContext(r.Context())
	token := extractCookie(r)

	mountName, err := ws.findUserMount(r, token)
	if err != nil {
		http.Redirect(w, r, "/dashboard", http.StatusFound)
		return
	}

	data := ws.baseData(r, info)
	data["MountName"] = mountName

	// Try to fetch the caller's own key.
	if keyInfo, err := ws.vault.GetUserPublicKey(r.Context(), token, mountName, info.Username); err == nil {
		data["OwnKey"] = keyInfo
	}

	if users, err := ws.vault.ListUsers(r.Context(), token, mountName); err == nil {
		data["Users"] = users
	}

	ws.renderTemplate(w, "user.html", data)
}

func (ws *WebServer) handleUserRegister(w http.ResponseWriter, r *http.Request) {
	info := tokenInfoFromContext(r.Context())
	token := extractCookie(r)

	mountName, err := ws.findUserMount(r, token)
	if err != nil {
		http.Error(w, "no user engine mounted", http.StatusNotFound)
		return
	}

	if _, err := ws.vault.UserRegister(r.Context(), token, mountName); err != nil {
		ws.renderUserWithError(w, r, mountName, info, grpcMessage(err))
		return
	}

	http.Redirect(w, r, "/user", http.StatusFound)
}

func (ws *WebServer) handleUserProvision(w http.ResponseWriter, r *http.Request) {
	info := tokenInfoFromContext(r.Context())
	if !info.IsAdmin {
		http.Error(w, "forbidden", http.StatusForbidden)
		return
	}

	token := extractCookie(r)
	mountName, err := ws.findUserMount(r, token)
	if err != nil {
		http.Error(w, "no user engine mounted", http.StatusNotFound)
		return
	}

	r.Body = http.MaxBytesReader(w, r.Body, 1<<20)
	_ = r.ParseForm()

	username := strings.TrimSpace(r.FormValue("username"))
	if username == "" {
		ws.renderUserWithError(w, r, mountName, info, "Username is required")
		return
	}

	if _, err := ws.vault.UserProvision(r.Context(), token, mountName, username); err != nil {
		ws.renderUserWithError(w, r, mountName, info, grpcMessage(err))
		return
	}

	http.Redirect(w, r, "/user", http.StatusFound)
}

func (ws *WebServer) handleUserKeyDetail(w http.ResponseWriter, r *http.Request) {
	info := tokenInfoFromContext(r.Context())
	token := extractCookie(r)

	mountName, err := ws.findUserMount(r, token)
	if err != nil {
		http.Error(w, "no user engine mounted", http.StatusNotFound)
		return
	}

	username := chi.URLParam(r, "username")
	keyInfo, err := ws.vault.GetUserPublicKey(r.Context(), token, mountName, username)
	if err != nil {
		st, _ := status.FromError(err)
		if st.Code() == codes.NotFound {
			http.Error(w, "user not found", http.StatusNotFound)
			return
		}
		http.Error(w, grpcMessage(err), http.StatusInternalServerError)
		return
	}

	data := ws.baseData(r, info)
	data["MountName"] = mountName
	data["KeyInfo"] = keyInfo
	ws.renderTemplate(w, "user_key_detail.html", data)
}

func (ws *WebServer) handleUserEncrypt(w http.ResponseWriter, r *http.Request) {
	info := tokenInfoFromContext(r.Context())
	token := extractCookie(r)

	mountName, err := ws.findUserMount(r, token)
	if err != nil {
		http.Error(w, "no user engine mounted", http.StatusNotFound)
		return
	}

	r.Body = http.MaxBytesReader(w, r.Body, 1<<20)
	_ = r.ParseForm()

	var recipients []string
	for _, line := range strings.Split(r.FormValue("recipients"), "\n") {
		if v := strings.TrimSpace(line); v != "" {
			recipients = append(recipients, v)
		}
	}
	plaintext := r.FormValue("plaintext")
	metadata := r.FormValue("metadata")

	if len(recipients) == 0 || plaintext == "" {
		ws.renderUserWithError(w, r, mountName, info, "Recipients and plaintext are required")
		return
	}

	envelope, err := ws.vault.UserEncrypt(r.Context(), token, mountName, plaintext, metadata, recipients)
	if err != nil {
		ws.renderUserWithError(w, r, mountName, info, grpcMessage(err))
		return
	}

	ws.renderUserWithResult(w, r, mountName, info, "EncryptResult", envelope)
}

func (ws *WebServer) handleUserDecrypt(w http.ResponseWriter, r *http.Request) {
	info := tokenInfoFromContext(r.Context())
	token := extractCookie(r)

	mountName, err := ws.findUserMount(r, token)
	if err != nil {
		http.Error(w, "no user engine mounted", http.StatusNotFound)
		return
	}

	r.Body = http.MaxBytesReader(w, r.Body, 1<<20)
	_ = r.ParseForm()

	envelope := r.FormValue("envelope")
	if envelope == "" {
		ws.renderUserWithError(w, r, mountName, info, "Envelope is required")
		return
	}

	result, err := ws.vault.UserDecrypt(r.Context(), token, mountName, envelope)
	if err != nil {
		ws.renderUserWithError(w, r, mountName, info, grpcMessage(err))
		return
	}

	ws.renderUserWithResult(w, r, mountName, info, "DecryptResult", result)
}

func (ws *WebServer) handleUserReEncrypt(w http.ResponseWriter, r *http.Request) {
	info := tokenInfoFromContext(r.Context())
	token := extractCookie(r)

	mountName, err := ws.findUserMount(r, token)
	if err != nil {
		http.Error(w, "no user engine mounted", http.StatusNotFound)
		return
	}

	r.Body = http.MaxBytesReader(w, r.Body, 1<<20)
	_ = r.ParseForm()

	envelope := r.FormValue("envelope")
	if envelope == "" {
		ws.renderUserWithError(w, r, mountName, info, "Envelope is required")
		return
	}

	newEnvelope, err := ws.vault.UserReEncrypt(r.Context(), token, mountName, envelope)
	if err != nil {
		ws.renderUserWithError(w, r, mountName, info, grpcMessage(err))
		return
	}

	ws.renderUserWithResult(w, r, mountName, info, "ReEncryptResult", newEnvelope)
}

func (ws *WebServer) handleUserRotateKey(w http.ResponseWriter, r *http.Request) {
	info := tokenInfoFromContext(r.Context())
	token := extractCookie(r)

	mountName, err := ws.findUserMount(r, token)
	if err != nil {
		http.Error(w, "no user engine mounted", http.StatusNotFound)
		return
	}

	if _, err := ws.vault.UserRotateKey(r.Context(), token, mountName); err != nil {
		ws.renderUserWithError(w, r, mountName, info, grpcMessage(err))
		return
	}

	http.Redirect(w, r, "/user", http.StatusSeeOther)
}

func (ws *WebServer) handleUserDeleteUser(w http.ResponseWriter, r *http.Request) {
	info := tokenInfoFromContext(r.Context())
	if !info.IsAdmin {
		http.Error(w, "forbidden", http.StatusForbidden)
		return
	}

	token := extractCookie(r)
	mountName, err := ws.findUserMount(r, token)
	if err != nil {
		http.Error(w, "no user engine mounted", http.StatusNotFound)
		return
	}

	username := chi.URLParam(r, "username")
	if err := ws.vault.UserDeleteUser(r.Context(), token, mountName, username); err != nil {
		http.Error(w, grpcMessage(err), http.StatusInternalServerError)
		return
	}

	http.Redirect(w, r, "/user", http.StatusSeeOther)
}

func (ws *WebServer) renderUserWithError(w http.ResponseWriter, r *http.Request, mountName string, info *TokenInfo, errMsg string) {
	token := extractCookie(r)
	data := ws.baseData(r, info)
	data["MountName"] = mountName
	data["Error"] = errMsg

	if keyInfo, err := ws.vault.GetUserPublicKey(r.Context(), token, mountName, info.Username); err == nil {
		data["OwnKey"] = keyInfo
	}
	if users, err := ws.vault.ListUsers(r.Context(), token, mountName); err == nil {
		data["Users"] = users
	}

	ws.renderTemplate(w, "user.html", data)
}

func (ws *WebServer) renderUserWithResult(w http.ResponseWriter, r *http.Request, mountName string, info *TokenInfo, resultKey string, result interface{}) {
	token := extractCookie(r)
	data := ws.baseData(r, info)
	data["MountName"] = mountName
	data[resultKey] = result

	if keyInfo, err := ws.vault.GetUserPublicKey(r.Context(), token, mountName, info.Username); err == nil {
		data["OwnKey"] = keyInfo
	}
	if users, err := ws.vault.ListUsers(r.Context(), token, mountName); err == nil {
		data["Users"] = users
	}

	ws.renderTemplate(w, "user.html", data)
}