package permissions

//go:generate go tool mockgen -package permissions -destination=manager_mock.go -source=./manager.go -build_flags=-mod=mod

import (
	"context"
	"net/http"

	log "github.com/sirupsen/logrus"

	"github.com/netbirdio/netbird/management/internals/modules/permissions/modules"
	"github.com/netbirdio/netbird/management/internals/modules/permissions/operations"
	"github.com/netbirdio/netbird/management/internals/modules/permissions/roles"
	"github.com/netbirdio/netbird/management/server/account"
	"github.com/netbirdio/netbird/management/server/activity"
	nbcontext "github.com/netbirdio/netbird/management/server/context"
	"github.com/netbirdio/netbird/management/server/store"
	"github.com/netbirdio/netbird/management/server/types"
	"github.com/netbirdio/netbird/shared/auth"
	"github.com/netbirdio/netbird/shared/management/http/util"
	"github.com/netbirdio/netbird/shared/management/status"
)

// AuthErrorHandler is called when an auth error occurs during permission validation.
// If it returns true, the error is considered handled and the default error response is skipped.
type AuthErrorHandler func(w http.ResponseWriter, r *http.Request, userAuth *auth.UserAuth, err error) bool

type Manager interface {
	WithPermission(module modules.Module, operation operations.Operation, handlerFunc func(w http.ResponseWriter, r *http.Request, auth *auth.UserAuth), authErrHandler ...AuthErrorHandler) http.HandlerFunc
	ValidateUserPermissions(ctx context.Context, accountID, userID string, module modules.Module, operation operations.Operation) (bool, context.Context, error)
	ValidateRoleModuleAccess(ctx context.Context, accountID string, role roles.RolePermissions, module modules.Module, operation operations.Operation) bool
	ValidateAccountAccess(ctx context.Context, accountID string, user *types.User, allowOwnerAndAdmin bool) (context.Context, error)

	GetPermissionsByRole(ctx context.Context, role types.UserRole) (roles.Permissions, error)
	SetAccountManager(accountManager account.Manager)
}

type managerImpl struct {
	store store.Store
}

func NewManager(store store.Store) Manager {
	return &managerImpl{
		store: store,
	}
}

// WithPermission wraps an HTTP handler with permission checking logic.
// An optional AuthErrorHandler can be provided to intercept auth errors before the default response is written.
// The wrapped handler receives a request whose context is enriched by the permission validation.
func (m *managerImpl) WithPermission(
	module modules.Module,
	operation operations.Operation,
	handlerFunc func(w http.ResponseWriter, r *http.Request, auth *auth.UserAuth),
	authErrHandler ...AuthErrorHandler,
) http.HandlerFunc {
	var onAuthErr AuthErrorHandler
	if len(authErrHandler) > 0 {
		onAuthErr = authErrHandler[0]
	}

	return func(w http.ResponseWriter, r *http.Request) {
		userAuth, err := nbcontext.GetUserAuthFromContext(r.Context())
		if err != nil {
			log.WithContext(r.Context()).Errorf("failed to get user auth from context: %v", err)
			util.WriteError(r.Context(), err, w)
			return
		}

		allowed, ctx, err := m.ValidateUserPermissions(r.Context(), userAuth.AccountId, userAuth.UserId, module, operation)
		enriched := r.WithContext(ctx)
		if err != nil {
			if onAuthErr != nil && onAuthErr(w, enriched, &userAuth, err) {
				return
			}
			log.WithContext(ctx).Errorf("failed to validate permissions for user %s on account %s: %v", userAuth.UserId, userAuth.AccountId, err)
			util.WriteError(ctx, status.NewPermissionValidationError(err), w)
			return
		}

		if !allowed {
			permErr := status.NewPermissionDeniedError()
			if onAuthErr != nil && onAuthErr(w, enriched, &userAuth, permErr) {
				return
			}
			log.WithContext(ctx).Tracef("user %s on account %s is not allowed to %s in %s", userAuth.UserId, userAuth.AccountId, operation, module)
			util.WriteError(ctx, permErr, w)
			return
		}

		handlerFunc(w, enriched, &userAuth)
	}
}

func (m *managerImpl) ValidateUserPermissions(
	ctx context.Context,
	accountID string,
	userID string,
	module modules.Module,
	operation operations.Operation,
) (bool, context.Context, error) {
	if userID == activity.SystemInitiator {
		return true, ctx, nil
	}

	user, err := m.store.GetUserByUserID(ctx, store.LockingStrengthNone, userID)
	if err != nil {
		return false, ctx, err
	}

	if user == nil {
		return false, ctx, status.NewUserNotFoundError(userID)
	}

	if user.IsBlocked() && !user.PendingApproval {
		return false, ctx, status.NewUserBlockedError()
	}

	if user.IsBlocked() && user.PendingApproval {
		return false, ctx, status.NewUserPendingApprovalError()
	}

	ctxEnriched, err := m.ValidateAccountAccess(ctx, accountID, user, false)
	if err != nil {
		return false, ctx, err
	}

	role, ok := roles.RolesMap[user.Role]
	if !ok {
		return false, ctxEnriched, status.NewUserRoleNotFoundError(string(user.Role))
	}

	return m.ValidateRoleModuleAccess(ctx, accountID, role, module, operation), ctxEnriched, nil
}

// ValidateRoleModuleAccess resolves an operation against the role's explicit
// grant for the module, then the grant for its parent module when the module
// is a dotted submodule, and finally the role's AutoAllowNew default.
func (m *managerImpl) ValidateRoleModuleAccess(
	ctx context.Context,
	accountID string,
	role roles.RolePermissions,
	module modules.Module,
	operation operations.Operation,
) bool {
	if permissions, ok := lookupModulePermissions(role, module); ok {
		if allowed, exists := permissions[operation]; exists {
			return allowed
		}
		log.WithContext(ctx).Tracef("operation %s not found on module %s for role %s", operation, module, role.Role)
		return false
	}

	return role.AutoAllowNew[operation]
}

// lookupModulePermissions returns the role's explicit permission set for the
// module, falling back to the parent module's set for dotted submodules. The
// second return reports whether any explicit set was found.
func lookupModulePermissions(role roles.RolePermissions, module modules.Module) (map[operations.Operation]bool, bool) {
	if permissions, ok := role.Permissions[module]; ok {
		return permissions, true
	}
	if parent, hasParent := module.Parent(); hasParent {
		if permissions, ok := role.Permissions[parent]; ok {
			return permissions, true
		}
	}
	return nil, false
}

func (m *managerImpl) ValidateAccountAccess(ctx context.Context, accountID string, user *types.User, allowOwnerAndAdmin bool) (context.Context, error) {
	if user.AccountID != accountID {
		return ctx, status.NewUserNotPartOfAccountError()
	}

	ctx = nbcontext.WithRole(ctx, string(user.Role))

	return ctx, nil
}

func (m *managerImpl) GetPermissionsByRole(ctx context.Context, role types.UserRole) (roles.Permissions, error) {
	roleMap, ok := roles.RolesMap[role]
	if !ok {
		return roles.Permissions{}, status.NewUserRoleNotFoundError(string(role))
	}

	permissions := roles.Permissions{}

	for k := range modules.All {
		if rolePermissions, ok := lookupModulePermissions(roleMap, k); ok {
			permissions[k] = rolePermissions
			continue
		}
		permissions[k] = roleMap.AutoAllowNew
	}

	return permissions, nil
}

func (m *managerImpl) SetAccountManager(accountManager account.Manager) {
	// no-op
}

// WrapHandler wraps a handler that expects UserAuth with context extraction.
// Unlike WithPermission, it does not perform any permission checks.
func WrapHandler(h func(w http.ResponseWriter, r *http.Request, userAuth *auth.UserAuth)) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		userAuth, err := nbcontext.GetUserAuthFromContext(r.Context())
		if err != nil {
			log.WithContext(r.Context()).Errorf("failed to get user auth from context: %v", err)
			util.WriteError(r.Context(), err, w)
			return
		}
		h(w, r, &userAuth)
	}
}