package cli

import (
	"fmt"
	"strings"

	"github.com/PerpetualSoftware/pad/internal/models"
)

// RenderRelationValue is the ONE place a hydrated `relation` value becomes text
// for a human (PLAN-2857 U6).
//
// A relation stores an item id, so the raw stored value is a UUID and reading
// it tells a person nothing. `relation_targets` already carries what is needed
// to render it, so this is a formatter over data the response holds — no
// lookup, and nothing here can fail.
//
//	resolved       -> "COLO-3 · Red"
//	id-only        -> "6f2c… (unavailable)"
//	stored as text -> "\"Red\" (text, not a reference)"
//
// STORED AS TEXT (BUG-3014) is neither of the other two. The value was never
// an id, so "(unavailable)" would claim a target that is gone or hidden when
// there was no target to lose. The wording says what the value is, not that
// anything is broken: it may well name a live item, and resolving it here would
// make the answer depend on who reads it.
//
// WHY "unavailable" AND NOT "deleted". An id-only entry has TWO causes that
// this layer cannot tell apart: the target is gone, or the requester may not
// see it. "(deleted)" would assert non-existence for both, which is false for
// half of them and is an existence claim the response does not support — the
// same defect codex round 12 found in the copy dialog, where the UI read
// `not_found` as "does not exist" when the server also emits it for a target
// the caller merely cannot see. The server works to make those two
// indistinguishable; the renderer must not undo that in the last inch.
// RenderRelationTargets renders one `relation_targets` entry — a scalar target,
// or a `multi_relation` LIST joined with ", " in stored order (PLAN-2857 U4).
//
// An EMPTY list renders as "(none)" rather than as an empty string: a field
// printed with nothing after it reads as a rendering bug, and the honest
// statement is that the field holds no references. A set with neither shape set
// renders empty, which is the caller's signal to fall back to the raw value.
func RenderRelationTargets(set models.RelationTargetSet) string {
	if set.List != nil {
		if len(set.List) == 0 {
			return "(none)"
		}
		parts := make([]string, len(set.List))
		for i, t := range set.List {
			parts[i] = RenderRelationValue(t)
		}
		return strings.Join(parts, ", ")
	}
	if set.One != nil {
		return RenderRelationValue(*set.One)
	}
	return ""
}

func RenderRelationValue(target models.RelationTarget) string {
	if target.StoredAsText {
		return fmt.Sprintf("%q (text, not a reference)", target.ID)
	}
	if target.Ref == "" {
		return fmt.Sprintf("%s (unavailable)", target.ID)
	}
	if target.Title == "" {
		// Ref without a title should not happen — they come from the same row —
		// but rendering "COLO-3 · " would look like a bug in the data rather
		// than in this function.
		return target.Ref
	}
	return fmt.Sprintf("%s · %s", target.Ref, target.Title)
}