package api

import (
	"fmt"
	"net/http"

	"github.com/grafana/grafana/pkg/middleware"
	ac "github.com/grafana/grafana/pkg/services/accesscontrol"
	acmiddleware "github.com/grafana/grafana/pkg/services/accesscontrol/middleware"
	"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 := acmiddleware.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}":
		eval = ac.EvalPermission(ac.ActionAlertingRuleDelete, dashboards.ScopeFoldersProvider.GetResourceScopeName(ac.Parameter(":Namespace")))
	case http.MethodDelete + "/api/ruler/grafana/api/v1/rules/{Namespace}":
		eval = ac.EvalPermission(ac.ActionAlertingRuleDelete, dashboards.ScopeFoldersProvider.GetResourceScopeName(ac.Parameter(":Namespace")))
	case http.MethodGet + "/api/ruler/grafana/api/v1/rules/{Namespace}/{Groupname}":
		eval = ac.EvalPermission(ac.ActionAlertingRuleRead, dashboards.ScopeFoldersProvider.GetResourceScopeName(ac.Parameter(":Namespace")))
	case http.MethodGet + "/api/ruler/grafana/api/v1/rules/{Namespace}":
		eval = ac.EvalPermission(ac.ActionAlertingRuleRead, dashboards.ScopeFoldersProvider.GetResourceScopeName(ac.Parameter(":Namespace")))
	case http.MethodGet + "/api/ruler/grafana/api/v1/rules":
		eval = ac.EvalPermission(ac.ActionAlertingRuleRead)
	case http.MethodPost + "/api/ruler/grafana/api/v1/rules/{Namespace}":
		scope := dashboards.ScopeFoldersProvider.GetResourceScopeName(ac.Parameter(":Namespace"))
		// more granular permissions are enforced by the handler via "authorizeRuleChanges"
		eval = ac.EvalAny(
			ac.EvalPermission(ac.ActionAlertingRuleUpdate, scope),
			ac.EvalPermission(ac.ActionAlertingRuleCreate, scope),
			ac.EvalPermission(ac.ActionAlertingRuleDelete, scope),
		)

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

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

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

	// 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)
	case http.MethodPost + "/api/alertmanager/grafana/api/v2/alerts":
		eval = ac.EvalAny(ac.EvalPermission(ac.ActionAlertingInstanceCreate), ac.EvalPermission(ac.ActionAlertingInstanceUpdate))

	// 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/{Recipient}/api/v2/silence/{SilenceId}":
		eval = ac.EvalPermission(ac.ActionAlertingInstancesExternalWrite, datasources.ScopeProvider.GetResourceScope(ac.Parameter(":Recipient")))
	case http.MethodPost + "/api/alertmanager/{Recipient}/api/v2/silences":
		eval = ac.EvalPermission(ac.ActionAlertingInstancesExternalWrite, datasources.ScopeProvider.GetResourceScope(ac.Parameter(":Recipient")))
	case http.MethodGet + "/api/alertmanager/{Recipient}/api/v2/silence/{SilenceId}":
		eval = ac.EvalPermission(ac.ActionAlertingInstancesExternalRead, datasources.ScopeProvider.GetResourceScope(ac.Parameter(":Recipient")))
	case http.MethodGet + "/api/alertmanager/{Recipient}/api/v2/silences":
		eval = ac.EvalPermission(ac.ActionAlertingInstancesExternalRead, datasources.ScopeProvider.GetResourceScope(ac.Parameter(":Recipient")))

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

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

	// 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.ActionAlertingNotificationsDelete)
	case http.MethodGet + "/api/alertmanager/grafana/config/api/v1/alerts":
		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.ActionAlertingNotificationsUpdate), ac.EvalPermission(ac.ActionAlertingNotificationsCreate), ac.EvalPermission(ac.ActionAlertingNotificationsDelete))
	case http.MethodPost + "/api/alertmanager/grafana/config/api/v1/receivers/test":
		eval = ac.EvalPermission(ac.ActionAlertingNotificationsRead)

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

	// 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
	}

	if eval != nil {
		return authorize(middleware.ReqSignedIn, eval)
	}

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