API contracts.

// An implicit endpoint serializes the domain object that happens to be handy.
// That silently makes internal fields part of the caller-facing API.
export function getProfileImplicit(id: string) {
	if (id !== profile.id) return { status: 404, body: { message: 'Missing' } };
	return { status: 200, body: { ...profile } };
}

type profileData struct {
	ID          string `json:"id"`
	DisplayName string `json:"displayName"`
	JoinedAt    string `json:"joinedAt"`
}

type profileResponse struct {
	Data profileData `json:"data"`
	Meta metadata    `json:"meta"`
}

type metadata struct {
	RequestID     string `json:"requestId"`
	SchemaVersion int    `json:"schemaVersion"`
}

type apiError struct {
	Code      string `json:"code"`
	Message   string `json:"message"`
	RequestID string `json:"requestId"`
}

type errorResponse struct {
	Error apiError `json:"error"`
}

func getProfile(id, requestID string) httpResponse {
	if id != storedProfile.ID {
		return httpResponse{
			Status: 404,
			Body:   errorResponse{Error: apiError{Code: "not_found", Message: "Profile was not found.", RequestID: requestID}},
		}
	}
	return httpResponse{
		Status: 200,
		Body: profileResponse{
			Data: profileData{ID: storedProfile.ID, DisplayName: storedProfile.DisplayName, JoinedAt: storedProfile.JoinedAt},
			Meta: metadata{RequestID: requestID, SchemaVersion: 1},
		},
	}
}

func getRateLimitedProfile(requestID string) httpResponse {
	return httpResponse{
		Status: 429,
		Body:   errorResponse{Error: apiError{Code: "rate_limited", Message: "Try again later.", RequestID: requestID}},
	}
}

export const profileContract = {
	method: 'GET',
	path: '/profiles/:id',
	success: '200 { data: { id, displayName, joinedAt }, meta: { requestId, schemaVersion } }',
	failure: '400 | 404 | 429 { error: { code, message, requestId } }'
} as const;

function errorResponse(code: ApiErrorCode, message: string, requestId: string): ErrorResponse {
	return { error: { code, message, requestId } };
}

export function getProfile(id: string, requestId: string): HttpResponse {
	if (id !== profile.id) {
		return { status: 404, body: errorResponse('not_found', 'Profile was not found.', requestId) };
	}
	return {
		status: 200,
		body: {
			data: {
				id: profile.id,
				displayName: profile.displayName,
				joinedAt: profile.joinedAt
			},
			meta: { requestId, schemaVersion: 1 }
		}
	};
}

export function getRateLimitedProfile(requestId: string): HttpResponse {
	return { status: 429, body: errorResponse('rate_limited', 'Try again later.', requestId) };
}