package api

import (
	"fmt"
	"net/http"

	"github.com/grafana/grafana/pkg/middleware"
	ac "github.com/grafana/grafana/pkg/services/accesscontrol"
	"github.com/grafana/grafana/pkg/services/dashboards"
	"github.com/grafana/grafana/pkg/services/datasources"
	"github.com/grafana/grafana/pkg/web"
)

//nolint:gocyclo
func (api *API) authorize(method, path string) web.Handler {
	authorize := ac.Middleware(api.AccessControl)
	var eval ac.Evaluator = nil

	switch method + path {
	// Alert Rules

	// Grafana Paths
	case http.MethodDelete + "/api/ruler/grafana/api/v1/rules/{Namespace}/{Groupname}",
		http.MethodDelete + "/api/ruler/grafana/api/v1/rules/{Namespace}":
		eval = ac.EvalAll(
			ac.EvalPermission(ac.ActionAlertingRuleDelete, dashboards.ScopeFoldersProvider.GetResourceScopeUID(ac.Parameter(":Namespace"))),
			ac.EvalPermission(ac.ActionAlertingRuleRead, dashboards.ScopeFoldersProvider.GetResourceScopeUID(ac.Parameter(":Namespace"))),
			ac.EvalPermission(dashboards.ActionFoldersRead, dashboards.ScopeFoldersProvider.GetResourceScopeUID(ac.Parameter(":Namespace"))),
		)
	case http.MethodGet + "/api/ruler/grafana/api/v1/rules/{Namespace}/{Groupname}":
		eval = ac.EvalAll(
			ac.EvalPermission(ac.ActionAlertingRuleRead, dashboards.ScopeFoldersProvider.GetResourceScopeUID(ac.Parameter(":Namespace"))),
			ac.EvalPermission(dashboards.ActionFoldersRead, dashboards.ScopeFoldersProvider.GetResourceScopeUID(ac.Parameter(":Namespace"))),
		)
	case http.MethodGet + "/api/ruler/grafana/api/v1/rules/{Namespace}":
		eval = ac.EvalAll(
			ac.EvalPermission(ac.ActionAlertingRuleRead, dashboards.ScopeFoldersProvider.GetResourceScopeUID(ac.Parameter(":Namespace"))),
			ac.EvalPermission(dashboards.ActionFoldersRead, dashboards.ScopeFoldersProvider.GetResourceScopeUID(ac.Parameter(":Namespace"))),
		)
	case http.MethodGet + "/api/ruler/grafana/api/v1/rules",
		http.MethodGet + "/api/ruler/grafana/api/v1/export/rules":
		eval = ac.EvalPermission(ac.ActionAlertingRuleRead)
	case http.MethodPost + "/api/ruler/grafana/api/v1/rules/{Namespace}/export":
		scope := dashboards.ScopeFoldersProvider.GetResourceScopeUID(ac.Parameter(":Namespace"))
		// more granular permissions are enforced by the handler via "authorizeRuleChanges"
		eval = ac.EvalAll(ac.EvalPermission(ac.ActionAlertingRuleRead, scope),
			ac.EvalPermission(dashboards.ActionFoldersRead, scope),
		)
	case http.MethodPost + "/api/ruler/grafana/api/v1/rules/{Namespace}":
		scope := dashboards.ScopeFoldersProvider.GetResourceScopeUID(ac.Parameter(":Namespace"))
		// more granular permissions are enforced by the handler via "authorizeRuleChanges"
		eval = ac.EvalAll(
			ac.EvalPermission(ac.ActionAlertingRuleRead, scope),
			ac.EvalPermission(dashboards.ActionFoldersRead, scope),
			ac.EvalAny(
				ac.EvalPermission(ac.ActionAlertingRuleUpdate, scope),
				ac.EvalPermission(ac.ActionAlertingRuleCreate, scope),
				ac.EvalPermission(ac.ActionAlertingRuleDelete, scope),
			),
		)

	// Grafana rule state history paths
	case http.MethodGet + "/api/v1/rules/history":
		eval = ac.EvalPermission(ac.ActionAlertingRuleRead)

	// Grafana receivers paths
	case http.MethodGet + "/api/v1/notifications/receivers":
		// additional authorization is done at the service level
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingNotificationsRead),
			ac.EvalPermission(ac.ActionAlertingReceiversList),
			ac.EvalPermission(ac.ActionAlertingReceiversRead),
			ac.EvalPermission(ac.ActionAlertingReceiversReadSecrets),
		)
	case http.MethodGet + "/api/v1/notifications/receivers/{Name}":
		// TODO: scope to :Name
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingReceiversRead),
			ac.EvalPermission(ac.ActionAlertingReceiversReadSecrets),
		)

	// Grafana, Prometheus-compatible Paths
	case http.MethodGet + "/api/prometheus/grafana/api/v1/rules":
		eval = ac.EvalPermission(ac.ActionAlertingRuleRead)

	// Grafana Rules Testing Paths
	case http.MethodPost + "/api/v1/rule/test/grafana":
		// additional authorization is done in the request handler
		eval = ac.EvalPermission(ac.ActionAlertingRuleRead)
	// Grafana Rules Testing Paths
	case http.MethodPost + "/api/v1/rule/backtest":
		// additional authorization is done in the request handler
		eval = ac.EvalPermission(ac.ActionAlertingRuleRead)
	case http.MethodPost + "/api/v1/eval":
		// additional authorization is done in the request handler
		eval = ac.EvalPermission(ac.ActionAlertingRuleRead)

	// Lotex Paths
	case http.MethodDelete + "/api/ruler/{DatasourceUID}/api/v1/rules/{Namespace}":
		eval = ac.EvalPermission(ac.ActionAlertingRuleExternalWrite, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))
	case http.MethodDelete + "/api/ruler/{DatasourceUID}/api/v1/rules/{Namespace}/{Groupname}":
		eval = ac.EvalPermission(ac.ActionAlertingRuleExternalWrite, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))
	case http.MethodGet + "/api/ruler/{DatasourceUID}/api/v1/rules/{Namespace}":
		eval = ac.EvalPermission(ac.ActionAlertingRuleExternalRead, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))
	case http.MethodGet + "/api/ruler/{DatasourceUID}/api/v1/rules/{Namespace}/{Groupname}":
		eval = ac.EvalPermission(ac.ActionAlertingRuleExternalRead, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))
	case http.MethodGet + "/api/ruler/{DatasourceUID}/api/v1/rules":
		eval = ac.EvalPermission(ac.ActionAlertingRuleExternalRead, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))
	case http.MethodPost + "/api/ruler/{DatasourceUID}/api/v1/rules/{Namespace}":
		eval = ac.EvalPermission(ac.ActionAlertingInstancesExternalWrite, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))

	// Lotex Prometheus-compatible Paths
	case http.MethodGet + "/api/prometheus/{DatasourceUID}/api/v1/rules":
		eval = ac.EvalPermission(ac.ActionAlertingRuleExternalRead, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))

	// Lotex Rules testing
	case http.MethodPost + "/api/v1/rule/test/{DatasourceUID}":
		eval = ac.EvalPermission(ac.ActionAlertingRuleExternalRead, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))

	// Alert Instances and Silences

	// Silences. Grafana Paths
	case http.MethodDelete + "/api/alertmanager/grafana/api/v2/silence/{SilenceId}":
		eval = ac.EvalPermission(ac.ActionAlertingInstanceUpdate) // delete endpoint actually expires silence
	case http.MethodGet + "/api/alertmanager/grafana/api/v2/silence/{SilenceId}":
		eval = ac.EvalPermission(ac.ActionAlertingInstanceRead)
	case http.MethodGet + "/api/alertmanager/grafana/api/v2/silences":
		eval = ac.EvalPermission(ac.ActionAlertingInstanceRead)
	case http.MethodPost + "/api/alertmanager/grafana/api/v2/silences":
		// additional authorization is done in the request handler
		eval = ac.EvalAny(ac.EvalPermission(ac.ActionAlertingInstanceCreate), ac.EvalPermission(ac.ActionAlertingInstanceUpdate))

	// Alert Instances. Grafana Paths
	case http.MethodGet + "/api/alertmanager/grafana/api/v2/alerts/groups":
		eval = ac.EvalPermission(ac.ActionAlertingInstanceRead)
	case http.MethodGet + "/api/alertmanager/grafana/api/v2/alerts":
		eval = ac.EvalPermission(ac.ActionAlertingInstanceRead)

	// Grafana Prometheus-compatible Paths
	case http.MethodGet + "/api/prometheus/grafana/api/v1/alerts":
		eval = ac.EvalPermission(ac.ActionAlertingInstanceRead)

	// Silences. External AM.
	case http.MethodDelete + "/api/alertmanager/{DatasourceUID}/api/v2/silence/{SilenceId}":
		eval = ac.EvalPermission(ac.ActionAlertingInstancesExternalWrite, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))
	case http.MethodPost + "/api/alertmanager/{DatasourceUID}/api/v2/silences":
		eval = ac.EvalPermission(ac.ActionAlertingInstancesExternalWrite, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))
	case http.MethodGet + "/api/alertmanager/{DatasourceUID}/api/v2/silence/{SilenceId}":
		eval = ac.EvalPermission(ac.ActionAlertingInstancesExternalRead, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))
	case http.MethodGet + "/api/alertmanager/{DatasourceUID}/api/v2/silences":
		eval = ac.EvalPermission(ac.ActionAlertingInstancesExternalRead, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))

	// Alert instances. External AM.
	case http.MethodGet + "/api/alertmanager/{DatasourceUID}/api/v2/alerts/groups":
		eval = ac.EvalPermission(ac.ActionAlertingInstancesExternalRead, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))
	case http.MethodGet + "/api/alertmanager/{DatasourceUID}/api/v2/alerts":
		eval = ac.EvalPermission(ac.ActionAlertingInstancesExternalRead, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))
	case http.MethodPost + "/api/alertmanager/{DatasourceUID}/api/v2/alerts":
		eval = ac.EvalPermission(ac.ActionAlertingInstancesExternalWrite, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))

	// Prometheus-compatible Paths
	case http.MethodGet + "/api/prometheus/{DatasourceUID}/api/v1/alerts":
		eval = ac.EvalPermission(ac.ActionAlertingInstancesExternalRead, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))

	// Notification Policies, Contact Points and Templates

	// Grafana Paths
	case http.MethodDelete + "/api/alertmanager/grafana/config/api/v1/alerts": // reset alertmanager config to the default
		eval = ac.EvalPermission(ac.ActionAlertingNotificationsWrite)
	case http.MethodGet + "/api/alertmanager/grafana/config/api/v1/alerts":
		eval = ac.EvalPermission(ac.ActionAlertingNotificationsRead)
	case http.MethodGet + "/api/alertmanager/grafana/config/history":
		eval = ac.EvalPermission(ac.ActionAlertingNotificationsRead)
	case http.MethodGet + "/api/alertmanager/grafana/api/v2/status":
		eval = ac.EvalPermission(ac.ActionAlertingNotificationsRead)
	case http.MethodPost + "/api/alertmanager/grafana/config/api/v1/alerts":
		// additional authorization is done in the request handler
		eval = ac.EvalAny(ac.EvalPermission(ac.ActionAlertingNotificationsWrite))
	case http.MethodPost + "/api/alertmanager/grafana/config/history/{id}/_activate":
		eval = ac.EvalAny(ac.EvalPermission(ac.ActionAlertingNotificationsWrite))
	case http.MethodGet + "/api/alertmanager/grafana/config/api/v1/receivers":
		eval = ac.EvalPermission(ac.ActionAlertingNotificationsRead)
	case http.MethodPost + "/api/alertmanager/grafana/config/api/v1/receivers/test":
		eval = ac.EvalPermission(ac.ActionAlertingNotificationsWrite)
	case http.MethodPost + "/api/alertmanager/grafana/config/api/v1/templates/test":
		eval = ac.EvalPermission(ac.ActionAlertingNotificationsWrite)

	// External Alertmanager Paths
	case http.MethodDelete + "/api/alertmanager/{DatasourceUID}/config/api/v1/alerts":
		eval = ac.EvalPermission(ac.ActionAlertingNotificationsExternalWrite, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))
	case http.MethodGet + "/api/alertmanager/{DatasourceUID}/api/v2/status":
		eval = ac.EvalPermission(ac.ActionAlertingNotificationsExternalRead, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))
	case http.MethodGet + "/api/alertmanager/{DatasourceUID}/config/api/v1/alerts":
		eval = ac.EvalPermission(ac.ActionAlertingNotificationsExternalRead, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))
	case http.MethodPost + "/api/alertmanager/{DatasourceUID}/config/api/v1/alerts":
		eval = ac.EvalPermission(ac.ActionAlertingNotificationsExternalWrite, datasources.ScopeProvider.GetResourceScopeUID(ac.Parameter(":DatasourceUID")))

	case http.MethodGet + "/api/v1/ngalert":
		// let user with any alerting permission access this API
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingInstanceRead),
			ac.EvalPermission(ac.ActionAlertingInstancesExternalRead),
			ac.EvalPermission(ac.ActionAlertingRuleRead),
			ac.EvalPermission(ac.ActionAlertingRuleExternalRead),
			ac.EvalPermission(ac.ActionAlertingNotificationsRead),
			ac.EvalPermission(ac.ActionAlertingNotificationsExternalRead),
		)
	// Raw Alertmanager Config Paths
	case http.MethodDelete + "/api/v1/ngalert/admin_config",
		http.MethodGet + "/api/v1/ngalert/admin_config",
		http.MethodPost + "/api/v1/ngalert/admin_config",
		http.MethodGet + "/api/v1/ngalert/alertmanagers":
		return middleware.ReqOrgAdmin

	// Grafana-only Provisioning Read Paths
	case http.MethodGet + "/api/v1/provisioning/policies/export",
		http.MethodGet + "/api/v1/provisioning/contact-points/export",
		http.MethodGet + "/api/v1/provisioning/mute-timings/export",
		http.MethodGet + "/api/v1/provisioning/mute-timings/{name}/export":
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingNotificationsRead),       // organization scope
			ac.EvalPermission(ac.ActionAlertingProvisioningRead),        // organization scope
			ac.EvalPermission(ac.ActionAlertingProvisioningReadSecrets), // organization scope
		)

	case http.MethodGet + "/api/v1/provisioning/alert-rules",
		http.MethodGet + "/api/v1/provisioning/alert-rules/export":
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingProvisioningRead),
			ac.EvalPermission(ac.ActionAlertingProvisioningReadSecrets),
			ac.EvalAll( // scopes are enforced in the handler
				ac.EvalPermission(ac.ActionAlertingRuleRead),
				ac.EvalPermission(dashboards.ActionFoldersRead),
			),
		)
	case http.MethodGet + "/api/v1/provisioning/alert-rules/{UID}",
		http.MethodGet + "/api/v1/provisioning/alert-rules/{UID}/export":
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingProvisioningRead),
			ac.EvalPermission(ac.ActionAlertingProvisioningReadSecrets),
			ac.EvalAll(
				ac.EvalPermission(ac.ActionAlertingRuleRead),
				ac.EvalPermission(dashboards.ActionFoldersRead),
			),
		)

	case http.MethodGet + "/api/v1/provisioning/folder/{FolderUID}/rule-groups/{Group}",
		http.MethodGet + "/api/v1/provisioning/folder/{FolderUID}/rule-groups/{Group}/export":
		scope := dashboards.ScopeFoldersProvider.GetResourceScopeUID(ac.Parameter(":FolderUID"))
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingProvisioningRead),
			ac.EvalPermission(ac.ActionAlertingProvisioningReadSecrets),
			ac.EvalAll(
				ac.EvalPermission(ac.ActionAlertingRuleRead, scope),
				ac.EvalPermission(dashboards.ActionFoldersRead, scope),
			),
		)

	case http.MethodGet + "/api/v1/provisioning/policies",
		http.MethodGet + "/api/v1/provisioning/contact-points",
		http.MethodGet + "/api/v1/provisioning/templates",
		http.MethodGet + "/api/v1/provisioning/templates/{name}",
		http.MethodGet + "/api/v1/provisioning/mute-timings",
		http.MethodGet + "/api/v1/provisioning/mute-timings/{name}":
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingProvisioningRead),
			ac.EvalPermission(ac.ActionAlertingProvisioningReadSecrets),
			ac.EvalPermission(ac.ActionAlertingNotificationsRead),
		)

	// Grafana-only Provisioning Write Paths
	case http.MethodPost + "/api/v1/provisioning/alert-rules":
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingProvisioningWrite),
			ac.EvalAll(
				ac.EvalPermission(ac.ActionAlertingRuleCreate), // more granular permissions are enforced by the handler via "authorizeRuleChanges"
				ac.EvalPermission(ac.ActionAlertingProvisioningSetStatus),
			),
		)
	case http.MethodPut + "/api/v1/provisioning/alert-rules/{UID}":
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingProvisioningWrite),
			ac.EvalAll(
				ac.EvalPermission(ac.ActionAlertingRuleUpdate), // more granular permissions are enforced by the handler via "authorizeRuleChanges"
				ac.EvalPermission(ac.ActionAlertingProvisioningSetStatus),
			),
		)
	case http.MethodDelete + "/api/v1/provisioning/alert-rules/{UID}":
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingProvisioningWrite),
			ac.EvalAll(
				ac.EvalPermission(ac.ActionAlertingRuleDelete), // more granular permissions are enforced by the handler via "authorizeRuleChanges"
				ac.EvalPermission(ac.ActionAlertingProvisioningSetStatus),
			),
		)
	case http.MethodDelete + "/api/v1/provisioning/folder/{FolderUID}/rule-groups/{Group}":
		scope := dashboards.ScopeFoldersProvider.GetResourceScopeUID(ac.Parameter(":FolderUID"))
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingProvisioningWrite),
			ac.EvalAll(
				ac.EvalPermission(ac.ActionAlertingRuleDelete, scope),
				ac.EvalPermission(ac.ActionAlertingRuleRead, scope),
				ac.EvalPermission(dashboards.ActionFoldersRead, scope),
				ac.EvalPermission(ac.ActionAlertingProvisioningSetStatus),
			),
		)
	case http.MethodPut + "/api/v1/provisioning/folder/{FolderUID}/rule-groups/{Group}":
		scope := dashboards.ScopeFoldersProvider.GetResourceScopeUID(ac.Parameter(":FolderUID"))
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingProvisioningWrite),
			ac.EvalAll(
				ac.EvalPermission(ac.ActionAlertingRuleRead, scope),
				ac.EvalPermission(dashboards.ActionFoldersRead, scope),
				ac.EvalPermission(ac.ActionAlertingProvisioningSetStatus),
				ac.EvalAny( // the exact permissions will be checked after the operations are determined
					ac.EvalPermission(ac.ActionAlertingRuleUpdate, scope),
					ac.EvalPermission(ac.ActionAlertingRuleCreate, scope),
					ac.EvalPermission(ac.ActionAlertingRuleDelete, scope),
				),
			),
		)

	case http.MethodPut + "/api/v1/provisioning/policies",
		http.MethodDelete + "/api/v1/provisioning/policies",
		http.MethodPost + "/api/v1/provisioning/contact-points",
		http.MethodPut + "/api/v1/provisioning/contact-points/{UID}",
		http.MethodDelete + "/api/v1/provisioning/contact-points/{UID}",
		http.MethodPut + "/api/v1/provisioning/templates/{name}",
		http.MethodDelete + "/api/v1/provisioning/templates/{name}",
		http.MethodPost + "/api/v1/provisioning/mute-timings",
		http.MethodPut + "/api/v1/provisioning/mute-timings/{name}",
		http.MethodDelete + "/api/v1/provisioning/mute-timings/{name}":
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingProvisioningWrite), // organization scope,
			ac.EvalAll(
				ac.EvalPermission(ac.ActionAlertingNotificationsWrite),
				ac.EvalPermission(ac.ActionAlertingProvisioningSetStatus),
			),
		)
	case http.MethodGet + "/api/v1/notifications/time-intervals/{name}",
		http.MethodGet + "/api/v1/notifications/time-intervals":
		eval = ac.EvalAny(ac.EvalPermission(ac.ActionAlertingNotificationsRead), ac.EvalPermission(ac.ActionAlertingNotificationsTimeIntervalsRead), ac.EvalPermission(ac.ActionAlertingProvisioningRead))
	}

	if eval != nil {
		return authorize(eval)
	}

	panic(fmt.Sprintf("no authorization handler for method [%s] of endpoint [%s]", method, path))
}