package ceph

import (
	"bytes"
	"fmt"
	"io"
	"net/netip"
	"strings"

	"github.com/gofrs/uuid/v5"

	"asciigoat.org/ini/basic"
)

// Config represents a ceph.conf file
type Config struct {
	Global GlobalConfig `ini:"global"`
}

// GlobalConfig represents the [global] section of a ceph.conf file
type GlobalConfig struct {
	FSID           uuid.UUID    `ini:"fsid"`
	Monitors       []string     `ini:"mon_initial_members,comma"`
	MonitorsAddr   []netip.Addr `ini:"mon_host,comma"`
	ClusterNetwork netip.Prefix `ini:"cluster_network"`
}

// WriteTo writes a Wireguard [Config] onto the provided [io.Writer]
func (cfg *Config) WriteTo(w io.Writer) (int64, error) {
	var buf bytes.Buffer

	writeGlobalToBuffer(&buf, &cfg.Global)
	return buf.WriteTo(w)
}

func writeGlobalToBuffer(w *bytes.Buffer, c *GlobalConfig) {
	_, _ = w.WriteString("[global]\n")
	_, _ = fmt.Fprintf(w, "%s = %s\n", "fsid", c.FSID.String())
	_, _ = fmt.Fprintf(w, "%s = %s\n", "mon_initial_members", strings.Join(c.Monitors, ", "))
	_, _ = fmt.Fprintf(w, "%s = %s\n", "mon_host", joinAddrs(c.MonitorsAddr, ", "))
	_, _ = fmt.Fprintf(w, "%s = %s\n", "cluster_network", c.ClusterNetwork.String())

	_, _ = fmt.Fprintf(w, "\n; %s\n", "don't rewrite labels on startup")
	_, _ = fmt.Fprintf(w, "%s = %s\n", "osd_class_update_on_start", "false")
}

func joinAddrs(addrs []netip.Addr, sep string) string {
	s := make([]string, len(addrs))

	for i, addr := range addrs {
		s[i] = addr.String()
	}

	return strings.Join(s, sep)
}

// NewConfigFromReader parses the ceph.conf file
func NewConfigFromReader(r io.Reader) (*Config, error) {
	doc, err := basic.Decode(r)
	if err != nil {
		return nil, err
	}

	cfg, err := newConfigFromDocument(doc)
	if err != nil {
		return nil, err
	}

	return cfg, nil
}