package accesscontrol

import (
	"context"
	"strings"

	"github.com/grafana/grafana/pkg/models"
)

type AccessControl interface {
	// Evaluate evaluates access to the given resource.
	Evaluate(ctx context.Context, user *models.SignedInUser, permission string, scope ...string) (bool, error)

	// GetUserPermissions returns user permissions.
	GetUserPermissions(ctx context.Context, user *models.SignedInUser) ([]*Permission, error)

	// Middleware checks if service disabled or not to switch to fallback authorization.
	IsDisabled() bool

	// DeclareFixedRoles allow the caller to declare, to the service, fixed roles and their
	// assignments to organization roles ("Viewer", "Editor", "Admin") or "Grafana Admin"
	DeclareFixedRoles(...RoleRegistration) error
}

func HasAccess(ac AccessControl, c *models.ReqContext) func(fallback func(*models.ReqContext) bool, permission string, scopes ...string) bool {
	return func(fallback func(*models.ReqContext) bool, permission string, scopes ...string) bool {
		if ac.IsDisabled() {
			return fallback(c)
		}

		hasAccess, err := ac.Evaluate(c.Req.Context(), c.SignedInUser, permission, scopes...)
		if err != nil {
			c.Logger.Error("Error from access control system", "error", err)
			return false
		}

		return hasAccess
	}
}

var ReqGrafanaAdmin = func(c *models.ReqContext) bool {
	return c.IsGrafanaAdmin
}

var ReqOrgAdmin = func(c *models.ReqContext) bool {
	return c.OrgRole == models.ROLE_ADMIN
}

func BuildPermissionsMap(permissions []*Permission) map[string]bool {
	permissionsMap := make(map[string]bool)
	for _, p := range permissions {
		permissionsMap[p.Action] = true
	}

	return permissionsMap
}

func ValidateScope(scope string) bool {
	prefix, last := scope[:len(scope)-1], scope[len(scope)-1]
	// verify that last char is either ':' or '/' if last character of scope is '*'
	if len(prefix) > 0 && last == '*' {
		lastChar := prefix[len(prefix)-1]
		if lastChar != ':' && lastChar != '/' {
			return false
		}
	}
	return !strings.ContainsAny(prefix, "*?")
}