/*
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 es

import (
	"context"
	"fmt"
	"log/slog"
	"slices"
	"strings"
	"sync"

	"codeberg.org/scip/esctl/pkg/cfg"
	"codeberg.org/scip/esctl/pkg/printer"
	"github.com/dustin/go-humanize"
	"github.com/elastic/go-elasticsearch/v9/typedapi/ccr/stats"
	"github.com/elastic/go-elasticsearch/v9/typedapi/cluster/health"
	clusterstats "github.com/elastic/go-elasticsearch/v9/typedapi/cluster/stats"
	"github.com/elastic/go-elasticsearch/v9/typedapi/core/info"
	"github.com/elastic/go-elasticsearch/v9/typedapi/types"
)

const (
	ResponseHealth = iota
	ResponseInfo
	ResponseCcr
	ResponseStats
)

type ClusterIndices map[string]map[string]*types.IndicesRecord

type apiResponse struct {
	error  error
	info   *info.Response
	health *health.Response
	ccr    *stats.Response
	stats  *clusterstats.Response
	which  int
}

func ClusterList(conf *cfg.Config) error {
	table := printer.NewTable(conf, 3, len(conf.Clusters))

	table.Addheaders("cluster", "uri", "default")

	idx := 0

	names := make([]string, len(conf.Clusters))
	for name := range conf.Clusters {
		names[idx] = name
		idx++
	}

	slices.Sort(names)

	for idx, name := range names {
		current := name == "default" || name == conf.CurrentCluster
		cluster := conf.Clusters[name]

		_, err := cluster.ES.Cluster.Health().
			Header("content-type", "application/json").
			Header("accept", "application/json").
			Do(context.Background())

		if err == nil {
			name = printer.Colorize(conf, "green", name)
		}

		table.Entries[idx] = []string{name, cluster.Uri, fmt.Sprintf("%t", current)}
	}

	if err := table.Print(); err != nil {
		return err
	}

	return nil
}

// We're using goroutines  here to parallelize API  requests, since we
// have to do 3 of'em for each cluster. This speeds things up.
func ClusterStatus(conf *cfg.Config) error {
	clusters := []string{}
	gocount := 3
	if conf.Verbose {
		gocount++
	}

	if conf.All {
		for key := range conf.Clusters {
			clusters = append(clusters, key)
		}
	} else {
		clusters = []string{"default"}
	}

	for _, cluster := range clusters {
		es := conf.DefaultCluster.ES
		if cluster != "default" {
			es = conf.Clusters[cluster].ES
		}

		responses := make(chan apiResponse, gocount)
		wg := &sync.WaitGroup{}

		wg.Add(gocount)
		go getClusterData(es, wg, responses, "health")
		go getClusterData(es, wg, responses, "info")
		go getClusterData(es, wg, responses, "ccrstats")

		if conf.Verbose {
			go getClusterData(es, wg, responses, "stats")
		}

		wg.Wait()

		var clusterhealth *health.Response
		var info *info.Response
		var ccrstats *stats.Response
		var clusterstats *clusterstats.Response

		for i := 0; i < gocount; i++ {
			r := <-responses

			if r.error != nil {
				return r.error
			}

			switch r.which {
			case ResponseHealth:
				clusterhealth = r.health
			case ResponseCcr:
				ccrstats = r.ccr
			case ResponseInfo:
				info = r.info
			case ResponseStats:
				clusterstats = r.stats
			}
		}

		slog.Debug("ES result", "cluster health", clusterhealth)

		ccrfollowing := ""
		if len(ccrstats.AutoFollowStats.AutoFollowedClusters) > 0 {
			// is following another cluster
			ccrfollowing = fmt.Sprintf("%s (%d/%d)",
				ccrstats.AutoFollowStats.AutoFollowedClusters[0].ClusterName,
				ccrstats.AutoFollowStats.NumberOfSuccessfulFollowIndices,
				ccrstats.AutoFollowStats.NumberOfFailedFollowIndices,
			)
		}

		table := printer.NewTable(conf, 2, 5)
		table.Addheaders(cluster, "status")

		table.Entries = [][]string{
			{"Cluster Name", printer.Colorize(conf, clusterhealth.Status.Name, clusterhealth.ClusterName)},
			{"ES Version", info.Version.Int},
			{"Active Shards", fmt.Sprintf("%d", clusterhealth.ActiveShards)},
			{"Active Primary Shards", fmt.Sprintf("%d", clusterhealth.ActivePrimaryShards)},
			{"Nodes", fmt.Sprintf("%d", clusterhealth.NumberOfNodes)},
			{"AutoFollow (success/failed indices)", ccrfollowing},
		}

		if conf.Verbose {
			table = gatherClusterStats(conf, clusterstats, table)
		}

		if err := table.Print(); err != nil {
			return err
		}
	}

	return nil
}

func gatherClusterStats(conf *cfg.Config, clusterstats *clusterstats.Response, table *printer.Table) *printer.Table {
	var querycount int64
	var vmversion string

	for _, count := range clusterstats.Indices.Search.Queries {
		querycount += count
	}

	if len(clusterstats.Nodes.Jvm.Versions) > 0 {
		vmversion = strings.Join([]string{
			clusterstats.Nodes.Jvm.Versions[0].VmName,
			clusterstats.Nodes.Jvm.Versions[0].VmVersion}, " ")
	}

	isleader := checkClusterIsLeader(conf, conf.CurrentCluster)

	table.Entries = append(table.Entries, [][]string{
		{"Indicies", fmt.Sprintf("%d", clusterstats.Indices.Count)},
		{"Is Leader", fmt.Sprintf("%t", isleader)},
		{"Docs", fmt.Sprintf("%d", clusterstats.Indices.Docs.Count)},
		{"Total Size", humanize.Bytes(uint64(clusterstats.Indices.Docs.TotalSizeInBytes))},
		{"Total Queries", fmt.Sprintf("%d", querycount)},
		{"Shards Primaries", fmt.Sprintf("%d", clusterstats.Indices.Shards.Primaries)},
		{"Shards Total", fmt.Sprintf("%d", clusterstats.Indices.Shards.Total)},
		{"Storage", fmt.Sprintf(
			"%s/%s",
			humanize.Bytes(uint64(clusterstats.Indices.Store.SizeInBytes)),
			humanize.Bytes(uint64(*clusterstats.Indices.Store.TotalDataSetSizeInBytes)),
		)},
		{"JVM Heap", fmt.Sprintf(
			"%s/%s",
			humanize.Bytes(uint64(clusterstats.Nodes.Jvm.Mem.HeapUsedInBytes)),
			humanize.Bytes(uint64(clusterstats.Nodes.Jvm.Mem.HeapMaxInBytes)),
		)},
		{"JVM Threads", fmt.Sprintf("%d", clusterstats.Nodes.Jvm.Threads)},
		{"JVM Version", vmversion},
		{"CPUs", fmt.Sprintf("%d", clusterstats.Nodes.Os.AllocatedProcessors)},
		{"CPU Usage", fmt.Sprintf("%d%%", clusterstats.Nodes.Process.Cpu.Percent)},
		{"Open FDs", fmt.Sprintf("%d", clusterstats.Nodes.Process.OpenFileDescriptors.Avg)},
	}...)

	return table
}