package holder

import "fmt"

// FindingReadSide is the finding of a store whose read side does not answer through the program.
const FindingReadSide = "read-side-down"

// ProbeName is the name the health check lists on each seat: any name answers, an empty list included.
const ProbeName = Self + "/program"

// Health is distribution's health check (design 51 *While the program is down*; ADR 0240), run by the runtime each
// minute outside the program's process: it asks `versions` of each seat it holds through the store's read side, the
// program's port (front), and answers what failed, naming the program. The finding is written while it fails and
// cleared once it answers.
func Health(front Catalog, finding func(kind, subject, words string, raised bool)) (map[string]any, error) {
	answered := map[string]int{}
	for _, seat := range Seats {
		got, err := front.Versions(ProbeName)
		if err != nil {
			words := fmt.Sprintf("the store's read side does not answer %s's versions through distribution's program (port 5000): %v; is the program distribution running?", seat, err)
			if finding != nil {
				finding(FindingReadSide, seat, words, true)
			}
			return nil, fmt.Errorf("%s", words)
		}
		answered[seat] = len(got)
	}
	if finding != nil {
		for _, seat := range Seats {
			finding(FindingReadSide, seat, "", false)
		}
	}
	return map[string]any{"healthy": true, "versions": answered}, nil
}