package libraryelements

import (
	"errors"
	"net/http"

	"github.com/grafana/grafana/pkg/api/response"
	"github.com/grafana/grafana/pkg/api/routing"
	"github.com/grafana/grafana/pkg/infra/metrics"
	ac "github.com/grafana/grafana/pkg/services/accesscontrol"
	contextmodel "github.com/grafana/grafana/pkg/services/contexthandler/model"
	"github.com/grafana/grafana/pkg/services/dashboards"
	"github.com/grafana/grafana/pkg/services/featuremgmt"
	"github.com/grafana/grafana/pkg/services/folder"
	"github.com/grafana/grafana/pkg/services/libraryelements/model"
	"github.com/grafana/grafana/pkg/web"
)

func (l *LibraryElementService) registerAPIEndpoints() {
	authorize := ac.Middleware(l.AccessControl)

	l.RouteRegister.Group("/api/library-elements", func(entities routing.RouteRegister) {
		uidScope := ScopeLibraryPanelsProvider.GetResourceScopeUID(ac.Parameter(":uid"))

		if l.features.IsEnabledGlobally(featuremgmt.FlagLibraryPanelRBAC) {
			entities.Post("/", authorize(ac.EvalPermission(ActionLibraryPanelsCreate)), routing.Wrap(l.createHandler))
			entities.Delete("/:uid", authorize(ac.EvalPermission(ActionLibraryPanelsDelete, uidScope)), routing.Wrap(l.deleteHandler))
			entities.Get("/", authorize(ac.EvalPermission(ActionLibraryPanelsRead)), routing.Wrap(l.getAllHandler))
			entities.Get("/:uid", authorize(ac.EvalPermission(ActionLibraryPanelsRead)), routing.Wrap(l.getHandler))
			entities.Get("/:uid/connections/", authorize(ac.EvalPermission(ActionLibraryPanelsRead, uidScope)), routing.Wrap(l.getConnectionsHandler))
			entities.Get("/name/:name", routing.Wrap(l.getByNameHandler))
			entities.Patch("/:uid", authorize(ac.EvalPermission(ActionLibraryPanelsWrite, uidScope)), routing.Wrap(l.patchHandler))
		} else {
			entities.Post("/", routing.Wrap(l.createHandler))
			entities.Delete("/:uid", routing.Wrap(l.deleteHandler))
			entities.Get("/", routing.Wrap(l.getAllHandler))
			entities.Get("/:uid", routing.Wrap(l.getHandler))
			entities.Get("/:uid/connections/", routing.Wrap(l.getConnectionsHandler))
			entities.Get("/name/:name", routing.Wrap(l.getByNameHandler))
			entities.Patch("/:uid", routing.Wrap(l.patchHandler))
		}
	})
}

// swagger:route POST /library-elements library_elements createLibraryElement
//
// Create library element.
//
// Creates a new library element.
//
// Responses:
// 200: getLibraryElementResponse
// 400: badRequestError
// 401: unauthorisedError
// 403: forbiddenError
// 404: notFoundError
// 500: internalServerError
func (l *LibraryElementService) createHandler(c *contextmodel.ReqContext) response.Response {
	cmd := model.CreateLibraryElementCommand{}
	if err := web.Bind(c.Req, &cmd); err != nil {
		return response.Error(http.StatusBadRequest, "bad request data", err)
	}

	if cmd.FolderUID != nil {
		if *cmd.FolderUID == "" {
			metrics.MFolderIDsServiceCount.WithLabelValues(metrics.LibraryElements).Inc()
			// nolint:staticcheck
			cmd.FolderID = 0
			generalFolderUID := ac.GeneralFolderUID
			cmd.FolderUID = &generalFolderUID
		} else {
			folder, err := l.folderService.Get(c.Req.Context(), &folder.GetFolderQuery{OrgID: c.SignedInUser.GetOrgID(), UID: cmd.FolderUID, SignedInUser: c.SignedInUser})
			if err != nil || folder == nil {
				return response.ErrOrFallback(http.StatusBadRequest, "failed to get folder", err)
			}
			metrics.MFolderIDsServiceCount.WithLabelValues(metrics.LibraryElements).Inc()
			// nolint:staticcheck
			cmd.FolderID = folder.ID
		}
	}

	element, err := l.createLibraryElement(c.Req.Context(), c.SignedInUser, cmd)
	if err != nil {
		return toLibraryElementError(err, "Failed to create library element")
	}

	metrics.MFolderIDsServiceCount.WithLabelValues(metrics.LibraryElements).Inc()
	// nolint:staticcheck
	if element.FolderID != 0 {
		metrics.MFolderIDsServiceCount.WithLabelValues(metrics.LibraryElements).Inc()
		// nolint:staticcheck
		folder, err := l.folderService.Get(c.Req.Context(), &folder.GetFolderQuery{OrgID: c.SignedInUser.GetOrgID(), ID: &element.FolderID, SignedInUser: c.SignedInUser})
		if err != nil {
			return response.ErrOrFallback(http.StatusInternalServerError, "failed to get folder", err)
		}
		element.FolderUID = folder.UID
		element.Meta.FolderUID = folder.UID
		element.Meta.FolderName = folder.Title
	}

	return response.JSON(http.StatusOK, model.LibraryElementResponse{Result: element})
}

// swagger:route DELETE /library-elements/{library_element_uid} library_elements deleteLibraryElementByUID
//
// Delete library element.
//
// Deletes an existing library element as specified by the UID. This operation cannot be reverted.
// You cannot delete a library element that is connected. This operation cannot be reverted.
//
// Responses:
// 200: okResponse
// 400: badRequestError
// 401: unauthorisedError
// 403: forbiddenError
// 404: notFoundError
// 500: internalServerError
func (l *LibraryElementService) deleteHandler(c *contextmodel.ReqContext) response.Response {
	id, err := l.deleteLibraryElement(c.Req.Context(), c.SignedInUser, web.Params(c.Req)[":uid"])
	if err != nil {
		return toLibraryElementError(err, "Failed to delete library element")
	}

	return response.JSON(http.StatusOK, model.DeleteLibraryElementResponse{
		Message: "Library element deleted",
		ID:      id,
	})
}

// swagger:route GET /library-elements/{library_element_uid} library_elements getLibraryElementByUID
//
// Get library element by UID.
//
// Returns a library element with the given UID.
//
// Responses:
// 200: getLibraryElementResponse
// 401: unauthorisedError
// 403: forbiddenError
// 404: notFoundError
// 500: internalServerError
func (l *LibraryElementService) getHandler(c *contextmodel.ReqContext) response.Response {
	ctx := c.Req.Context()
	element, err := l.getLibraryElementByUid(ctx, c.SignedInUser,
		model.GetLibraryElementCommand{
			UID:        web.Params(c.Req)[":uid"],
			FolderName: dashboards.RootFolderName,
		},
	)
	if err != nil {
		return toLibraryElementError(err, "Failed to get library element")
	}

	if l.features.IsEnabled(ctx, featuremgmt.FlagLibraryPanelRBAC) {
		allowed, err := l.AccessControl.Evaluate(ctx, c.SignedInUser, ac.EvalPermission(ActionLibraryPanelsRead, ScopeLibraryPanelsProvider.GetResourceScopeUID(web.Params(c.Req)[":uid"])))
		if err != nil {
			return response.Error(http.StatusInternalServerError, "unable to evaluate library panel permissions", err)
		} else if !allowed {
			return response.Error(http.StatusForbidden, "insufficient permissions for getting library panel", err)
		}
	}

	return response.JSON(http.StatusOK, model.LibraryElementResponse{Result: element})
}

// swagger:route GET /library-elements library_elements getLibraryElements
//
// Get all library elements.
//
// Returns a list of all library elements the authenticated user has permission to view.
// Use the `perPage` query parameter to control the maximum number of library elements returned; the default limit is `100`.
// You can also use the `page` query parameter to fetch library elements from any page other than the first one.
//
// Responses:
// 200: getLibraryElementsResponse
// 401: unauthorisedError
// 500: internalServerError
func (l *LibraryElementService) getAllHandler(c *contextmodel.ReqContext) response.Response {
	query := model.SearchLibraryElementsQuery{
		PerPage:          c.QueryInt("perPage"),
		Page:             c.QueryInt("page"),
		SearchString:     c.Query("searchString"),
		SortDirection:    c.Query("sortDirection"),
		Kind:             c.QueryInt("kind"),
		TypeFilter:       c.Query("typeFilter"),
		ExcludeUID:       c.Query("excludeUid"),
		FolderFilter:     c.Query("folderFilter"),
		FolderFilterUIDs: c.Query("folderFilterUIDs"),
	}
	elementsResult, err := l.getAllLibraryElements(c.Req.Context(), c.SignedInUser, query)
	if err != nil {
		return toLibraryElementError(err, "Failed to get library elements")
	}

	if l.features.IsEnabled(c.Req.Context(), featuremgmt.FlagLibraryPanelRBAC) {
		filteredPanels, err := l.filterLibraryPanelsByPermission(c, elementsResult.Elements)
		if err != nil {
			return toLibraryElementError(err, "Failed to evaluate permissions")
		}
		elementsResult.Elements = filteredPanels
	}

	return response.JSON(http.StatusOK, model.LibraryElementSearchResponse{Result: elementsResult})
}

// swagger:route PATCH /library-elements/{library_element_uid} library_elements updateLibraryElement
//
// Update library element.
//
// Updates an existing library element identified by uid.
//
// Responses:
// 200: getLibraryElementResponse
// 400: badRequestError
// 401: unauthorisedError
// 403: forbiddenError
// 404: notFoundError
// 412: preconditionFailedError
// 500: internalServerError
func (l *LibraryElementService) patchHandler(c *contextmodel.ReqContext) response.Response {
	cmd := model.PatchLibraryElementCommand{}
	if err := web.Bind(c.Req, &cmd); err != nil {
		return response.Error(http.StatusBadRequest, "bad request data", err)
	}

	if cmd.FolderUID != nil {
		if *cmd.FolderUID == "" {
			metrics.MFolderIDsServiceCount.WithLabelValues(metrics.LibraryElements).Inc()
			// nolint:staticcheck
			cmd.FolderID = 0
		} else {
			folder, err := l.folderService.Get(c.Req.Context(), &folder.GetFolderQuery{OrgID: c.SignedInUser.GetOrgID(), UID: cmd.FolderUID, SignedInUser: c.SignedInUser})
			if err != nil || folder == nil {
				return response.Error(http.StatusBadRequest, "failed to get folder", err)
			}
			metrics.MFolderIDsServiceCount.WithLabelValues(metrics.LibraryElements).Inc()
			// nolint:staticcheck
			cmd.FolderID = folder.ID
		}
	}

	element, err := l.patchLibraryElement(c.Req.Context(), c.SignedInUser, cmd, web.Params(c.Req)[":uid"])
	if err != nil {
		return toLibraryElementError(err, "Failed to update library element")
	}

	metrics.MFolderIDsServiceCount.WithLabelValues(metrics.LibraryElements).Inc()
	// nolint:staticcheck
	if element.FolderID != 0 {
		metrics.MFolderIDsServiceCount.WithLabelValues(metrics.LibraryElements).Inc()
		// nolint:staticcheck
		folder, err := l.folderService.Get(c.Req.Context(), &folder.GetFolderQuery{OrgID: c.SignedInUser.GetOrgID(), ID: &element.FolderID, SignedInUser: c.SignedInUser})
		if err != nil {
			return response.Error(http.StatusInternalServerError, "failed to get folder", err)
		}
		element.FolderUID = folder.UID
		element.Meta.FolderUID = folder.UID
		element.Meta.FolderName = folder.Title
	}

	return response.JSON(http.StatusOK, model.LibraryElementResponse{Result: element})
}

// swagger:route GET /library-elements/{library_element_uid}/connections/ library_elements getLibraryElementConnections
//
// Get library element connections.
//
// Returns a list of connections for a library element based on the UID specified.
//
// Responses:
// 200: getLibraryElementConnectionsResponse
// 401: unauthorisedError
// 403: forbiddenError
// 404: notFoundError
// 500: internalServerError
func (l *LibraryElementService) getConnectionsHandler(c *contextmodel.ReqContext) response.Response {
	connections, err := l.getConnections(c.Req.Context(), c.SignedInUser, web.Params(c.Req)[":uid"])
	if err != nil {
		return toLibraryElementError(err, "Failed to get connections")
	}

	return response.JSON(http.StatusOK, model.LibraryElementConnectionsResponse{Result: connections})
}

// swagger:route GET /library-elements/name/{library_element_name} library_elements getLibraryElementByName
//
// Get library element by name.
//
// Returns a library element with the given name.
//
// Responses:
// 200: getLibraryElementArrayResponse
// 401: unauthorisedError
// 404: notFoundError
// 500: internalServerError
func (l *LibraryElementService) getByNameHandler(c *contextmodel.ReqContext) response.Response {
	elements, err := l.getLibraryElementsByName(c.Req.Context(), c.SignedInUser, web.Params(c.Req)[":name"])
	if err != nil {
		return toLibraryElementError(err, "Failed to get library element")
	}

	if l.features.IsEnabled(c.Req.Context(), featuremgmt.FlagLibraryPanelRBAC) {
		filteredElements, err := l.filterLibraryPanelsByPermission(c, elements)
		if err != nil {
			return toLibraryElementError(err, err.Error())
		}

		return response.JSON(http.StatusOK, model.LibraryElementArrayResponse{Result: filteredElements})
	} else {
		return response.JSON(http.StatusOK, model.LibraryElementArrayResponse{Result: elements})
	}
}

func (l *LibraryElementService) filterLibraryPanelsByPermission(c *contextmodel.ReqContext, elements []model.LibraryElementDTO) ([]model.LibraryElementDTO, error) {
	filteredPanels := make([]model.LibraryElementDTO, 0)
	for _, p := range elements {
		allowed, err := l.AccessControl.Evaluate(c.Req.Context(), c.SignedInUser, ac.EvalPermission(ActionLibraryPanelsRead, ScopeLibraryPanelsProvider.GetResourceScopeUID(p.UID)))
		if err != nil {
			return nil, err
		}
		if allowed {
			filteredPanels = append(filteredPanels, p)
		}
	}

	return filteredPanels, nil
}

func toLibraryElementError(err error, message string) response.Response {
	if errors.Is(err, model.ErrLibraryElementAlreadyExists) {
		return response.Error(http.StatusBadRequest, model.ErrLibraryElementAlreadyExists.Error(), err)
	}
	if errors.Is(err, model.ErrLibraryElementNotFound) {
		return response.Error(http.StatusNotFound, model.ErrLibraryElementNotFound.Error(), err)
	}
	if errors.Is(err, model.ErrLibraryElementDashboardNotFound) {
		return response.Error(http.StatusNotFound, model.ErrLibraryElementDashboardNotFound.Error(), err)
	}
	if errors.Is(err, model.ErrLibraryElementVersionMismatch) {
		return response.Error(http.StatusPreconditionFailed, model.ErrLibraryElementVersionMismatch.Error(), err)
	}
	if errors.Is(err, dashboards.ErrFolderNotFound) {
		return response.Error(http.StatusNotFound, dashboards.ErrFolderNotFound.Error(), err)
	}
	if errors.Is(err, dashboards.ErrFolderAccessDenied) {
		return response.Error(http.StatusForbidden, dashboards.ErrFolderAccessDenied.Error(), err)
	}
	if errors.Is(err, model.ErrLibraryElementHasConnections) {
		return response.Error(http.StatusForbidden, model.ErrLibraryElementHasConnections.Error(), err)
	}
	if errors.Is(err, model.ErrLibraryElementInvalidUID) {
		return response.Error(http.StatusBadRequest, model.ErrLibraryElementInvalidUID.Error(), err)
	}
	if errors.Is(err, model.ErrLibraryElementUIDTooLong) {
		return response.Error(http.StatusBadRequest, model.ErrLibraryElementUIDTooLong.Error(), err)
	}
	return response.ErrOrFallback(http.StatusInternalServerError, message, err)
}

// swagger:parameters getLibraryElementByUID getLibraryElementConnections
type LibraryElementByUID struct {
	// in:path
	// required:true
	UID string `json:"library_element_uid"`
}

// swagger:parameters getLibraryElementByUID
type GetLibraryElementByUIDParams struct {
	// in:path
	// required:true
	UID string `json:"library_element_uid"`
}

// swagger:parameters GetLibraryElementConnectionsParams
type GetLibraryElementConnectionsParams struct {
	// in:path
	// required:true
	UID string `json:"library_element_uid"`
}

// swagger:parameters deleteLibraryElementByUID
type DeleteLibraryElementByUIDParams struct {
	// in:path
	// required:true
	UID string `json:"library_element_uid"`
}

// swagger:parameters getLibraryElementByName
type LibraryElementByNameParams struct {
	// in:path
	// required:true
	Name string `json:"library_element_name"`
}

// swagger:parameters getLibraryElements
type GetLibraryElementsParams struct {
	// Part of the name or description searched for.
	// in:query
	// required:false
	SearchString string `json:"searchString"`
	// Kind of element to search for.
	// in:query
	// required:false
	// Description:
	// * 1 - library panels
	// * 2 - library variables
	// enum: 1,2
	Kind int `json:"kind"`
	// Sort order of elements.
	// in:query
	// required:false
	// Description:
	// * alpha-asc: ascending
	// * alpha-desc: descending
	// Enum: alpha-asc,alpha-desc
	SortDirection string `json:"sortDirection"`
	// A comma separated list of types to filter the elements by
	// in:query
	// required:false
	TypeFilter string `json:"typeFilter"`
	// Element UID to exclude from search results.
	// in:query
	// required:false
	ExcludeUID string `json:"excludeUid"`
	// A comma separated list of folder ID(s) to filter the elements by.
	// in:query
	// required:false
	FolderFilter string `json:"folderFilter"`
	// The number of results per page.
	// in:query
	// required:false
	// default: 100
	PerPage int `json:"perPage"`
	// The page for a set of records, given that only perPage records are returned at a time. Numbering starts at 1.
	// in:query
	// required:false
	// default: 1
	Page int `json:"page"`
}

// swagger:parameters createLibraryElement
type CreateLibraryElementParams struct {
	// in:body
	// required:true
	Body model.CreateLibraryElementCommand `json:"body"`
}

// swagger:parameters updateLibraryElement
type UpdateLibraryElementParam struct {
	// in:body
	// required:true
	Body model.PatchLibraryElementCommand `json:"body"`
	// in:path
	// required:true
	UID string `json:"library_element_uid"`
}

// swagger:response getLibraryElementsResponse
type GetLibraryElementsResponse struct {
	// in: body
	Body model.LibraryElementSearchResponse `json:"body"`
}

// swagger:response getLibraryElementResponse
type GetLibraryElementResponse struct {
	// in: body
	Body model.LibraryElementResponse `json:"body"`
}

// swagger:response getLibraryElementArrayResponse
type GetLibraryElementArrayResponse struct {
	// in: body
	Body model.LibraryElementArrayResponse `json:"body"`
}

// swagger:response getLibraryElementConnectionsResponse
type GetLibraryElementConnectionsResponse struct {
	// in: body
	Body model.LibraryElementConnectionsResponse `json:"body"`
}