package api

import (
	"crypto/rand"
	"encoding/hex"
	"encoding/json"
	"net/http"
	"strconv"

	"archivdms/internal/audit"
	"archivdms/internal/storage"
)

// --- Admin CRUD for per-tenant SFTP credentials (internal/sftpserver) ---
//
// Registered behind s.authAdmin (domain_admin/superadmin), tenant-scoped the
// same way handleListUsers/handleCreateUser are: sess.TenantID (from the
// domain_admin's own session) picks the tenant for domain admins, while a
// tenant-less (superadmin) session must specify tenant_id explicitly on
// create and cannot list/revoke without one — SFTP credentials always
// belong to exactly one tenant's inbox.

type createSFTPCredentialRequest struct {
	Username string `json:"username"`
	TenantID *int64 `json:"tenant_id,omitempty"` // required only for tenant-less (superadmin) sessions
}

type sftpCredentialCreatedResponse struct {
	storage.SFTPCredential
	Password string `json:"password"` // returned exactly once, in this response only
}

func (s *Server) handleCreateSFTPCredential(w http.ResponseWriter, r *http.Request) {
	sess := sessionFromCtx(r.Context())

	var req createSFTPCredentialRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}
	if req.Username == "" {
		writeError(w, http.StatusBadRequest, "username is required")
		return
	}

	tenantID := sess.TenantID
	if tenantID == nil {
		tenantID = req.TenantID
	}
	if tenantID == nil {
		writeError(w, http.StatusBadRequest, "tenant_id is required for tenant-less sessions")
		return
	}

	password, err := randomSFTPPassword()
	if err != nil {
		writeError(w, http.StatusInternalServerError, "generate password failed")
		return
	}

	cred, err := s.store.CreateSFTPCredential(r.Context(), *tenantID, req.Username, password)
	if err != nil {
		s.audlog.Log(audit.Entry{EventType: audit.EventSFTPCredentialCreate, Username: sess.Username, TenantID: tenantID, Success: false, Detail: err.Error()})
		writeError(w, http.StatusBadRequest, "create sftp credential failed (username may already be taken)")
		return
	}

	s.audlog.Log(audit.Entry{
		EventType: audit.EventSFTPCredentialCreate, Username: sess.Username, TenantID: tenantID,
		Success: true, Detail: "sftp_username:" + cred.Username,
	})

	writeJSON(w, http.StatusCreated, sftpCredentialCreatedResponse{SFTPCredential: *cred, Password: password})
}

func (s *Server) handleListSFTPCredentials(w http.ResponseWriter, r *http.Request) {
	sess := sessionFromCtx(r.Context())
	if sess.TenantID == nil {
		writeError(w, http.StatusForbidden, "tenant context required")
		return
	}
	creds, err := s.store.ListSFTPCredentials(r.Context(), *sess.TenantID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "list sftp credentials failed")
		return
	}
	writeJSON(w, http.StatusOK, creds)
}

func (s *Server) handleRevokeSFTPCredential(w http.ResponseWriter, r *http.Request) {
	sess := sessionFromCtx(r.Context())
	if sess.TenantID == nil {
		writeError(w, http.StatusForbidden, "tenant context required")
		return
	}
	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid credential id")
		return
	}
	if err := s.store.RevokeSFTPCredential(r.Context(), id, *sess.TenantID); err != nil {
		s.audlog.Log(audit.Entry{EventType: audit.EventSFTPCredentialRevoke, Username: sess.Username, TenantID: sess.TenantID, DocumentID: r.PathValue("id"), Success: false, Detail: err.Error()})
		writeError(w, http.StatusNotFound, "sftp credential not found")
		return
	}
	s.audlog.Log(audit.Entry{EventType: audit.EventSFTPCredentialRevoke, Username: sess.Username, TenantID: sess.TenantID, DocumentID: r.PathValue("id"), Success: true})
	writeJSON(w, http.StatusOK, map[string]string{"status": "revoked"})
}

func randomSFTPPassword() (string, error) {
	b := make([]byte, 20)
	if _, err := rand.Read(b); err != nil {
		return "", err
	}
	return hex.EncodeToString(b), nil
}