package main

import (
	"fmt"
	"os"
	"sort"
	"strings"
)

// generateBindConf produces a BIND domains.conf from all zone entries.
// Zones are sorted alphabetically. Each zone block uses 8-space indentation.
// DNSSEC zones get dnssec-policy and inline-signing directives on the file line.
func generateBindConf(entries []ZoneEntry) string {
	sorted := make([]ZoneEntry, len(entries))
	copy(sorted, entries)
	sort.Slice(sorted, func(i, j int) bool {
		return sorted[i].Zone < sorted[j].Zone
	})

	var b strings.Builder
	b.WriteString("# THIS FILE IS GENERATED BY catalog-zone-gen\n")
	b.WriteString("#=============================================\n")
	b.WriteString("#\n")

	for _, entry := range sorted {
		// Strip trailing dot for BIND zone name
		zoneName := strings.TrimSuffix(entry.Zone, ".")

		fmt.Fprintf(&b, "zone \"%s\" {\n", zoneName)
		b.WriteString("        type master;\n")

		fileLine := fmt.Sprintf("        file  \"%s\";", entry.ZoneFile)
		if entry.DNSSEC {
			fileLine += " dnssec-policy standard; inline-signing yes;"
		}
		b.WriteString(fileLine + "\n")
		b.WriteString("};\n")
	}

	return b.String()
}

// validateBindConf checks that every zone entry has a non-empty ZoneFile.
func validateBindConf(entries []ZoneEntry) error {
	for _, entry := range entries {
		if entry.ZoneFile == "" {
			return fmt.Errorf("%s:%d: zone %s missing file= property (required for --bind-conf)",
				entry.ZonesFile, entry.Line, entry.Zone)
		}
	}
	return nil
}

// writeBindConf validates entries and writes the BIND config to path.
func writeBindConf(path string, entries []ZoneEntry) error {
	if err := validateBindConf(entries); err != nil {
		return err
	}
	content := generateBindConf(entries)
	if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
		return fmt.Errorf("writing bind config %s: %w", path, err)
	}
	return nil
}