/*
Copyright © 2026 Thomas von Dein

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package cfg

import (
	"errors"
	"fmt"
	"net/http"
	"os"

	"github.com/elastic/elastic-transport-go/v8/elastictransport"
	"github.com/elastic/go-elasticsearch/v9"
	"gopkg.in/yaml.v3"
)

// used in general config struct
type Cluster struct {
	Uri, User, Pass string
	client          *elasticsearch.TypedClient
	Default         bool
}

// used just for writing back to the config file
type ClusterConfig struct {
	Uri, User, Pass string
	Default         bool
}

// to write the config, we avoid all other config settings
type WriteConfig struct {
	Clusters map[string]*ClusterConfig
}

func (cluster *Cluster) ES() *elasticsearch.TypedClient {
	if cluster.client == nil {
		fmt.Println("no current cluster, use 'esctl cluster switch <name>' to set one")
		os.Exit(1)
	}

	return cluster.client
}

func (cluster *Cluster) SetClient(client *elasticsearch.TypedClient) {
	cluster.client = client
}

// set Default=true for the given cluster in the config (if exists)
func (conf *Config) SwitchCluster(name string) error {
	_, exists := conf.Clusters[name]
	if !exists {
		return errors.New("no cluster with that name configured")
	}

	cfg := WriteConfig{Clusters: map[string]*ClusterConfig{}}

	for clustername, cluster := range conf.Clusters {
		cfg.Clusters[clustername] = &ClusterConfig{
			Uri:     cluster.Uri,
			User:    cluster.User,
			Pass:    cluster.Pass,
			Default: false,
		}

		if clustername == name {
			cfg.Clusters[clustername].Default = true
		}
	}

	raw, err := yaml.Marshal(cfg)
	if err != nil {
		return fmt.Errorf("failed to marshal cluster config: %w", err)
	}

	outfile := getDefaultPath()
	if conf.ConfigFile != "" {
		outfile = conf.ConfigFile
	}

	if err := os.WriteFile(outfile, raw, 0600); err != nil {
		return err
	}

	return nil
}

func (conf *Config) SetupES() error {
	// These headers are  not needed with ES 9, but with  ES 8, we set
	// them here  so every API call uses it.  The only exception being
	// the api repl, which does it on its own.
	headers := http.Header{}
	headers.Add("content-type", "application/json")
	headers.Add("Accept", "application/json")

	for _, cluster := range conf.Clusters {
		es, err := elasticsearch.NewTyped(
			elasticsearch.WithAddresses(cluster.Uri),
			elasticsearch.WithBasicAuth(cluster.User, cluster.Pass),
			elasticsearch.WithTransportOptions(
				conf.getTransport(),
				elastictransport.WithHeader(headers),
			),
		)

		if err != nil {
			return fmt.Errorf("failed to setup elasticsearch connection: %w", err)
		}

		cluster.SetClient(es)
	}

	return nil
}