package webserver

import (
	"net/http"
	"strconv"
	"strings"

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

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

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

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

	if keys, err := ws.vault.ListTransitKeys(r.Context(), token, mountName); err == nil {
		data["Keys"] = keys
	}

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

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

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

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

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

	// Fetch public key for asymmetric signing keys.
	switch key.Type {
	case "ed25519", "ecdsa-p256", "ecdsa-p384":
		if pubkey, err := ws.vault.GetTransitPublicKey(r.Context(), token, mountName, name); err == nil {
			data["PublicKey"] = pubkey
		}
	}

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

func (ws *WebServer) handleTransitCreateKey(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.findTransitMount(r, token)
	if err != nil {
		http.Error(w, "no transit engine mounted", http.StatusNotFound)
		return
	}

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

	name := strings.TrimSpace(r.FormValue("name"))
	if name == "" {
		ws.renderTransitWithError(w, r, mountName, info, "Key name is required")
		return
	}

	keyType := r.FormValue("type")
	if keyType == "" {
		keyType = "aes256-gcm"
	}

	if err := ws.vault.CreateTransitKey(r.Context(), token, mountName, name, keyType); err != nil {
		ws.renderTransitWithError(w, r, mountName, info, grpcMessage(err))
		return
	}

	http.Redirect(w, r, "/transit/key/"+name, http.StatusFound)
}

func (ws *WebServer) handleTransitRotateKey(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.findTransitMount(r, token)
	if err != nil {
		http.Error(w, "no transit engine mounted", http.StatusNotFound)
		return
	}

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

	http.Redirect(w, r, "/transit/key/"+name, http.StatusSeeOther)
}

func (ws *WebServer) handleTransitUpdateConfig(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.findTransitMount(r, token)
	if err != nil {
		http.Error(w, "no transit engine mounted", http.StatusNotFound)
		return
	}

	name := chi.URLParam(r, "name")
	r.Body = http.MaxBytesReader(w, r.Body, 1<<20)
	_ = r.ParseForm()

	minDecrypt := 0
	if v := r.FormValue("min_decryption_version"); v != "" {
		if n, err := strconv.Atoi(v); err == nil {
			minDecrypt = n
		}
	}
	allowDeletion := r.FormValue("allow_deletion") == "on"

	if err := ws.vault.UpdateTransitKeyConfig(r.Context(), token, mountName, name, minDecrypt, allowDeletion); err != nil {
		http.Error(w, grpcMessage(err), http.StatusInternalServerError)
		return
	}

	http.Redirect(w, r, "/transit/key/"+name, http.StatusSeeOther)
}

func (ws *WebServer) handleTransitTrimKey(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.findTransitMount(r, token)
	if err != nil {
		http.Error(w, "no transit engine mounted", http.StatusNotFound)
		return
	}

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

	http.Redirect(w, r, "/transit/key/"+name, http.StatusSeeOther)
}

func (ws *WebServer) handleTransitDeleteKey(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.findTransitMount(r, token)
	if err != nil {
		http.Error(w, "no transit engine mounted", http.StatusNotFound)
		return
	}

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

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

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

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

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

	key := r.FormValue("key")
	plaintext := r.FormValue("plaintext")
	transitCtx := r.FormValue("context")

	if key == "" || plaintext == "" {
		ws.renderTransitWithError(w, r, mountName, info, "Key and plaintext are required")
		return
	}

	ciphertext, err := ws.vault.TransitEncrypt(r.Context(), token, mountName, key, plaintext, transitCtx)
	if err != nil {
		ws.renderTransitWithError(w, r, mountName, info, grpcMessage(err))
		return
	}

	ws.renderTransitWithResult(w, r, mountName, info, "EncryptResult", ciphertext)
}

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

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

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

	key := r.FormValue("key")
	ciphertext := r.FormValue("ciphertext")
	transitCtx := r.FormValue("context")

	if key == "" || ciphertext == "" {
		ws.renderTransitWithError(w, r, mountName, info, "Key and ciphertext are required")
		return
	}

	plaintext, err := ws.vault.TransitDecrypt(r.Context(), token, mountName, key, ciphertext, transitCtx)
	if err != nil {
		ws.renderTransitWithError(w, r, mountName, info, grpcMessage(err))
		return
	}

	ws.renderTransitWithResult(w, r, mountName, info, "DecryptResult", plaintext)
}

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

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

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

	key := r.FormValue("key")
	ciphertext := r.FormValue("ciphertext")
	transitCtx := r.FormValue("context")

	if key == "" || ciphertext == "" {
		ws.renderTransitWithError(w, r, mountName, info, "Key and ciphertext are required")
		return
	}

	newCiphertext, err := ws.vault.TransitRewrap(r.Context(), token, mountName, key, ciphertext, transitCtx)
	if err != nil {
		ws.renderTransitWithError(w, r, mountName, info, grpcMessage(err))
		return
	}

	ws.renderTransitWithResult(w, r, mountName, info, "RewrapResult", newCiphertext)
}

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

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

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

	key := r.FormValue("key")
	input := r.FormValue("input")

	if key == "" || input == "" {
		ws.renderTransitWithError(w, r, mountName, info, "Key and input are required")
		return
	}

	signature, err := ws.vault.TransitSign(r.Context(), token, mountName, key, input)
	if err != nil {
		ws.renderTransitWithError(w, r, mountName, info, grpcMessage(err))
		return
	}

	ws.renderTransitWithResult(w, r, mountName, info, "SignResult", signature)
}

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

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

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

	key := r.FormValue("key")
	input := r.FormValue("input")
	signature := r.FormValue("signature")

	if key == "" || input == "" || signature == "" {
		ws.renderTransitWithError(w, r, mountName, info, "Key, input, and signature are required")
		return
	}

	valid, err := ws.vault.TransitVerify(r.Context(), token, mountName, key, input, signature)
	if err != nil {
		ws.renderTransitWithError(w, r, mountName, info, grpcMessage(err))
		return
	}

	ws.renderTransitWithResult(w, r, mountName, info, "VerifyResult", valid)
}

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

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

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

	key := r.FormValue("key")
	input := r.FormValue("input")

	if key == "" || input == "" {
		ws.renderTransitWithError(w, r, mountName, info, "Key and input are required")
		return
	}

	hmac, err := ws.vault.TransitHMAC(r.Context(), token, mountName, key, input)
	if err != nil {
		ws.renderTransitWithError(w, r, mountName, info, grpcMessage(err))
		return
	}

	ws.renderTransitWithResult(w, r, mountName, info, "HMACResult", hmac)
}

func (ws *WebServer) renderTransitWithError(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 keys, err := ws.vault.ListTransitKeys(r.Context(), token, mountName); err == nil {
		data["Keys"] = keys
	}

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

func (ws *WebServer) renderTransitWithResult(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 keys, err := ws.vault.ListTransitKeys(r.Context(), token, mountName); err == nil {
		data["Keys"] = keys
	}

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