package catalogue

import (
	"fmt"
	"regexp"
)

// What the machine's modules back up is placement (design 57 L3, issue 794). The holder of node-backup names it as
// `${backup:lines}` (what to run and which paths to keep) and `${backup:data}` (every item with its class and
// protection): the text `${contribution:node-backup:backup}` and `${contribution:node-backup:data}` render, from the
// same function, derived from each placed module's declared data (novox/hq ADR 0233). A handed holder has the text in
// its plan's placement for its client to fill; one not handed has the controller fill it where it stands.

// BackupNamespace is the placeholder kind of the machine's backup lines and data.
const BackupNamespace = "backup"

// ofBackup is where a holder places them: ${backup:<key>}. Loose inside the braces, so a misspelt key is found and
// refused rather than written out as text.
var ofBackup = regexp.MustCompile(`\$\{backup:([^}]*)\}`)

// backupKinds is the contribution kind each key of the backup placement renders.
var backupKinds = map[string]string{"lines": BackupKindBackup, "data": BackupKindData}

// backupPlacer is the machine's modules the backup placement is composed over, as the old contributions are.
type backupPlacer struct {
	modules  []Manifest
	with     Rendering
	facts    map[string]string
	caps     map[string]bool
	unplaced *[]string
}

// placed is the text of one key for a holder, or what is wrong with naming it.
func (b backupPlacer) placed(holder Manifest, key string, item bool) (string, string) {
	kind, known := backupKinds[key]
	switch {
	case item:
		return "", "an item is kept per item; the machine's backup lines are placed only in a file"
	case !known:
		return "", fmt.Sprintf("the backup placement has `lines` and `data`, not %q", key)
	case !holder.ClaimsSeat(BackupSeat):
		return "", fmt.Sprintf("%s does not claim %s; the machine's backup lines are placed by its holder alone "+
			"(novox/hq ADR 0212)", holder.Module, BackupSeat)
	}
	text, left, err := seatContributions(b.modules, holder, BackupSeat+":"+kind, b.with, b.facts, b.caps)
	if b.unplaced != nil {
		*b.unplaced = append(*b.unplaced, left...)
	}
	if err != nil {
		return "", err.Error()
	}
	return text, ""
}