package views

import (
	"fmt"
	"strings"
	"time"

	"git.novox.be/novox/mesh-sdk/go/health"
)

// The findings a views part writes in its own state `findings`, which the condition keeper raises and clears
// (novox/hq ADR 0564 §2): an owner's value too large for an event (TooLargeKind), and a reader's first view unanswered
// past its bound (UnansweredKind).
const (
	TooLargeKind   = "view-too-large"
	UnansweredKind = "first-view-unanswered"
)

// TooLargeFinding is the owner's finding of state's key too large to say whole on its views family.
func TooLargeFinding(owner, state, key string, size int, at time.Time) (string, []byte, error) {
	id := owner + "." + state + "." + key
	summary := fmt.Sprintf("%s's %s.%s holds %d bytes, more than one views event carries (%d): every reader asks its first view again at each change of it", owner, state, key, size, MaxValueBytes)
	return finding(owner, TooLargeKind, id, summary,
		fmt.Sprintf("A value of %s is too large for its views event", owner),
		"Each change of this key is said as a gap, so every reader of the state asks the owner's first view once more. "+
			"It works, but costs a first view per change; the value should be made smaller or split.", at)
}

// UnansweredFinding is a reader's finding of its first view of s unanswered past its bound (ADR 0615 §6): it names the
// owner and the tool. A first view answered at revision 0 with nothing in it is said too, with the operator's step.
func UnansweredFinding(reader string, s Status, at time.Time) (string, []byte, error) {
	id := reader + "." + s.Owner + "." + s.State
	summary := fmt.Sprintf("%s has no first view of %s's %s: %s has not answered since %s (%s)", reader, s.Owner, s.State, s.Tool,
		s.Asked.Format(time.RFC3339), strings.TrimSpace(s.Error))
	return finding(reader, UnansweredKind, id, summary,
		fmt.Sprintf("%s waits for %s", reader, s.Owner),
		fmt.Sprintf("%s reads %s's %s only through %s, and keeps asking it; it never reads the state itself. The answer clears this. "+
			"Look at %s's runtime of its own: is it running and connected?", reader, s.Owner, s.State, s.Tool, s.Owner), at)
}

func finding(observer, kind, id, summary, headline, explanation string, at time.Time) (string, []byte, error) {
	key := health.FindingKey(health.ScopeModule, id, kind)
	value, err := health.EncodeFinding(health.Finding{Key: key, Kind: kind, Subject: health.Subject{Scope: health.ScopeModule, ID: id},
		Severity: health.Warning, Summary: summary, Headline: headline, Explanation: explanation,
		Evidence: []health.Evidence{{At: at.UTC(), Said: summary}}, Source: observer + "." + kind, Observer: observer, At: at.UTC()})
	return key, value, err
}