//! A repo stolen from a Kepr that is not signed in: its own address, kept read-only.
//!
//! This is the addendum's one exception to the machine-wide remote rule. The
//! address lives in the repo's `state`, so nothing about it can leak into another
//! repo, and it is dropped the moment this machine signs in to that Kepr.

module exchange

import src.machine
import src.remote
import src.storage

const source_key = 'source'

// The address a stolen repo came from, `<base>/<repo>`, or '' for an ordinary repo.
pub fn source_of(store &storage.Store) string {
	return store.state(source_key) or { '' }
}

// The Kepr part of a source: what `koh remote <host>` would have to name.
pub fn source_host(source string) string {
	return source.all_before_last('/')
}

// True when this machine was set up by `koh remote <host>` for the same host, so that host's
// addresses are this machine's own bucket (Part 2 of the addendum).
pub fn signed_in_to(host string) bool {
	settings := machine.load_remote() or { return false }
	return settings.kind == machine.kind_s3 && settings.kepr != '' && settings.kepr == host
}

// read_only opens the backend a stolen repo came from: public, and never written to.
pub fn read_only(source string) !remote.Backend {
	return remote.new_web(source_host(source))!
}

// remember_source and forget_source are the only two writes: a repo is either a stolen one or an
// ordinary one, never both.
pub fn remember_source(store &storage.Store, source string) ! {
	store.set_state(source_key, source)!
}

pub fn forget_source(store &storage.Store) ! {
	store.set_state(source_key, '')!
}