// Validate makes sure the CORS definition origin is valid.
func (cors *CORSDefinition) Validate() *dslengine.ValidationErrors {
	verr := new(dslengine.ValidationErrors)
	if strings.Count(cors.Origin, "*") > 1 {
		verr.Add(cors, "invalid origin, can only contain one wildcard character")
	}
	return verr
}

func (a *APIDefinition) validateLicense(verr *dslengine.ValidationErrors) {
	if a.License != nil && a.License.URL != "" {
		if _, err := url.ParseRequestURI(a.License.URL); err != nil {
			verr.Add(a, "invalid license URL value: %s", err)
		}
	}
}

// Validate checks that the route definition is consistent: it has a parent.
func (r *RouteDefinition) Validate() *dslengine.ValidationErrors {
	verr := new(dslengine.ValidationErrors)
	if r.Parent == nil {
		verr.Add(r, "missing route parent action")
	}
	return verr.AsError()
}

func (a *APIDefinition) validateContact(verr *dslengine.ValidationErrors) {
	if a.Contact != nil && a.Contact.URL != "" {
		if _, err := url.ParseRequestURI(a.Contact.URL); err != nil {
			verr.Add(a, "invalid contact URL value: %s", err)
		}
	}
}

func (a *APIDefinition) validateDocs(verr *dslengine.ValidationErrors) {
	if a.Docs != nil && a.Docs.URL != "" {
		if _, err := url.ParseRequestURI(a.Docs.URL); err != nil {
			verr.Add(a, "invalid docs URL value: %s", err)
		}
	}
}

func (r *ResourceDefinition) validateParent(verr *dslengine.ValidationErrors) {
	p, ok := Design.Resources[r.ParentName]
	if !ok {
		verr.Add(r, "Parent resource named %#v not found", r.ParentName)
	} else {
		if p.CanonicalAction() == nil {
			verr.Add(r, "Parent resource %#v has no canonical action", r.ParentName)
		}
	}
}

func (r *ResourceDefinition) validateActions(version *APIVersionDefinition, verr *dslengine.ValidationErrors) {
	found := false
	for _, a := range r.Actions {
		if a.Name == r.CanonicalActionName {
			found = true
		}
		verr.Merge(a.Validate(version))
	}
	if r.CanonicalActionName != "" && !found {
		verr.Add(r, `unknown canonical action "%s"`, r.CanonicalActionName)
	}
}

// Validate makes sure the CORS definition origin is valid.
func (cors *CORSDefinition) Validate() *dslengine.ValidationErrors {
	verr := new(dslengine.ValidationErrors)
	if !cors.Regexp && strings.Count(cors.Origin, "*") > 1 {
		verr.Add(cors, "invalid origin, can only contain one wildcard character")
	}
	if cors.Regexp {
		_, err := regexp.Compile(cors.Origin)
		if err != nil {
			verr.Add(cors, "invalid origin, should be a valid regular expression")
		}
	}
	return verr
}

func (r *ResourceDefinition) validateBaseParams(verr *dslengine.ValidationErrors) {
	baseParams, ok := r.BaseParams.Type.(Object)
	if !ok {
		verr.Add(r, "invalid type for BaseParams, must be an Object", r)
	} else {
		vars := ExtractWildcards(r.BasePath)
		if len(vars) > 0 {
			if len(vars) != len(baseParams) {
				verr.Add(r, "BasePath defines parameters %s but BaseParams has %d elements",
					strings.Join([]string{
						strings.Join(vars[:len(vars)-1], ", "),
						vars[len(vars)-1],
					}, " and "),
					len(baseParams),
				)
			}
			for _, v := range vars {
				if _, found := baseParams[v]; !found {
					verr.Add(r, "Variable %s from base path %s does not match any parameter from BaseParams",
						v, r.BasePath)
				}
			}
		} else {
			if len(baseParams) > 0 {
				verr.Add(r, "BasePath does not use variables defined in BaseParams")
			}
		}
	}
}

func (a *APIDefinition) validateVersionParams(verr *dslengine.ValidationErrors) {
	bwcs := ExtractWildcards(a.BasePath)
	for _, param := range a.VersionParams {
		found := false
		for _, wc := range bwcs {
			if wc == param {
				found = true
				break
			}
		}
		if !found {
			verr.Add(a, "invalid version param, %s is not an API base path param (base path is %#v)",
				param, a.BasePath)
		}
	}
}

// Validate tests whether the RelationalStore definition is consistent.
func (a *RelationalStoreDefinition) Validate() *dslengine.ValidationErrors {
	fmt.Println("Validating Store")
	verr := new(dslengine.ValidationErrors)
	if a.Name == "" {
		verr.Add(a, "store name not defined")
	}
	if a.Parent == nil {
		verr.Add(a, "missing storage group parent")
	}
	a.IterateModels(func(model *RelationalModelDefinition) error {
		verr.Merge(model.Validate())
		return nil
	})

	return verr.AsError()
}

// ValidateParams checks the action parameters (make sure they have names, members and types).
func (a *ActionDefinition) ValidateParams(version *APIVersionDefinition) *dslengine.ValidationErrors {
	verr := new(dslengine.ValidationErrors)
	if a.Params == nil {
		return nil
	}
	params, ok := a.Params.Type.(Object)
	if !ok {
		verr.Add(a, `"Params" field of action is not an object`)
	}
	var wcs []string
	for _, r := range a.Routes {
		rwcs := ExtractWildcards(r.FullPath(version))
		for _, rwc := range rwcs {
			found := false
			for _, wc := range wcs {
				if rwc == wc {
					found = true
					break
				}
			}
			if !found {
				wcs = append(wcs, rwc)
			}
		}
	}
	for n, p := range params {
		if n == "" {
			verr.Add(a, "action has parameter with no name")
		} else if p == nil {
			verr.Add(a, "definition of parameter %s cannot be nil", n)
		} else if p.Type == nil {
			verr.Add(a, "type of parameter %s cannot be nil", n)
		}
		if p.Type.Kind() == ObjectKind {
			verr.Add(a, `parameter %s cannot be an object, only action payloads may be of type object`, n)
		}
		ctx := fmt.Sprintf("parameter %s", n)
		verr.Merge(p.Validate(ctx, a))
	}
	for _, resp := range a.Responses {
		verr.Merge(resp.Validate())
	}
	return verr.AsError()
}

// Validate tests whether the attribute definition is consistent: required fields exist.
// Since attributes are unaware of their context, additional context information can be provided
// to be used in error messages.
// The parent definition context is automatically added to error messages.
func (a *AttributeDefinition) Validate(ctx string, parent dslengine.Definition) *dslengine.ValidationErrors {
	if validated[a] {
		return nil
	}
	validated[a] = true
	verr := new(dslengine.ValidationErrors)
	if a.Type == nil {
		verr.Add(parent, "attribute type is nil")
		return verr
	}
	if ctx != "" {
		ctx += " - "
	}
	o := a.Type.ToObject()
	if o != nil {
		for _, n := range a.AllRequired() {
			found := false
			for an := range o {
				if n == an {
					found = true
					break
				}
			}
			if !found {
				verr.Add(parent, `%srequired field "%s" does not exist`, ctx, n)
			}
		}
		for n, att := range o {
			ctx = fmt.Sprintf("field %s", n)
			verr.Merge(att.Validate(ctx, a))
		}
	} else {
		if a.Type.IsArray() {
			elemType := a.Type.ToArray().ElemType
			verr.Merge(elemType.Validate(ctx, a))
		}
	}

	return verr.AsError()
}