/*
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"
	"encoding/json"
	"errors"
	"fmt"
	"log/slog"
	"maps"
	"strconv"
	"strings"

	"codeberg.org/scip/esctl/pkg/cfg"
	"codeberg.org/scip/esctl/pkg/printer"
	"github.com/elastic/go-elasticsearch/v9/typedapi/esdsl"
	"github.com/elastic/go-elasticsearch/v9/typedapi/types"
)

// used for completion
func IndexTemplateNames(conf *cfg.Config) ([]string, error) {
	res, err := conf.DefaultCluster.ES().Indices.GetIndexTemplate().
		Do(context.Background())
	if err != nil {
		return nil, fmt.Errorf("failed to get index templates: %w", esErrorString(err))
	}

	names := make([]string, len(res.IndexTemplates))

	for idx, tpl := range res.IndexTemplates {
		names[idx] = tpl.Name
	}

	return names, nil
}

func IndexTemplateList(conf *cfg.Config, filter string) error {
	res, err := conf.DefaultCluster.ES().Indices.GetIndexTemplate().
		Do(context.Background())
	if err != nil {
		return fmt.Errorf("failed to get index templates: %w", esErrorString(err))
	}

	slog.Debug("res", "index templates", res)

	table := printer.NewTable(conf, 5, 0)
	table.Addheaders("name", "description", "index patterns", "priority")

	for _, tpl := range res.IndexTemplates {
		if !conf.Hidden && strings.HasPrefix(tpl.Name, ".") {
			continue
		}

		if filter != "" && !strings.Contains(tpl.Name, filter) {
			continue
		}

		if len(conf.Filter) > 0 {
			skip := true

			for _, filter := range conf.Filter {
				for _, pattern := range tpl.IndexTemplate.IndexPatterns {
					if strings.Contains(pattern, filter) {
						skip = false
					}
				}
			}

			if skip {
				continue
			}
		}

		desc := strings.TrimPrefix(strings.TrimSuffix(string(tpl.IndexTemplate.Meta_["description"]), `"`), `"`)

		var prio int64
		if tpl.IndexTemplate.Priority != nil {
			prio = *tpl.IndexTemplate.Priority
		}

		table.AddRow(tpl.Name, desc, tpl.IndexTemplate.IndexPatterns, prio)
	}

	table.Sort()

	return table.Print()
}

func IndexTemplateShow(conf *cfg.Config, tplname string) error {
	res, err := conf.DefaultCluster.ES().Indices.GetIndexTemplate().
		Name(tplname).
		Do(context.Background())
	if err != nil {
		return fmt.Errorf("failed to get index template: %w", esErrorString(err))
	}

	slog.Debug("res", "index template", res)

	if len(res.IndexTemplates) != 1 {
		return errors.New("multiple or no index template matched the pattern")
	}

	tpl := res.IndexTemplates[0]

	table := printer.NewTable(conf, 2, 6)
	table.Addheaders("index template property", "value")

	desc, err := json.Marshal(tpl.IndexTemplate.Meta_["description"])
	if err != nil {
		return fmt.Errorf("failed to unmarshal meta json data: %w", err)
	}

	hasds := tpl.IndexTemplate.DataStream != nil

	aliases := []string{}
	for alias := range tpl.IndexTemplate.Template.Aliases {
		aliases = append(aliases, alias)
	}

	table.Entries = [][]any{
		{"name", tpl.Name},
		{"description", desc},
		{"index patterns", tpl.IndexTemplate.IndexPatterns},
		{"composed of", tpl.IndexTemplate.ComposedOf},
		{"data stream enabled", hasds},
		{"aliases", aliases},
	}

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

	table = printer.NewTable(conf, 2, 0)
	table.Addheaders("index setting property", "value")

	err = getIndexTemplateSettings(conf, tplname, table)
	if err != nil {
		return err
	}

	fmt.Println()

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

	table = printer.NewTable(conf, 2, 0)
	table.Addheaders("index field mapping", "type")

	if tpl.IndexTemplate.Template.Mappings != nil {
		for name, field := range tpl.IndexTemplate.Template.Mappings.Properties {
			typeval := ""

			switch val := field.(type) {
			case *types.IntegerNumberProperty:
				typeval = val.Type
			case *types.KeywordProperty:
				typeval = val.Type
			case *types.DateProperty:
				typeval = val.Type
			}

			table.AddRow(name, typeval)
		}

		fmt.Println()

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

	return nil
}

func IndexTemplateCreate(conf *cfg.Config, name string, mappings []string) error {
	settings := esdsl.NewIndexSettings()
	maps := esdsl.NewIndexTemplateMapping()

	create := conf.DefaultCluster.ES().Indices.PutIndexTemplate(name)

	if conf.Shards > 0 {
		settings.NumberOfShards(strconv.Itoa(conf.Shards))
	}

	if conf.Replicas > 0 {
		settings.NumberOfReplicas(strconv.Itoa(conf.Replicas))
	}

	if conf.Policy != "" {
		settings.Lifecycle(
			esdsl.NewIndexSettingsLifecycle().
				Name(conf.Policy))
	}

	if conf.Stream {
		create.DataStream(esdsl.NewDataStreamVisibility())

		if conf.Retention != "" {
			maps.Lifecycle(
				esdsl.NewDataStreamLifecycle().
					DataRetention(
						esdsl.NewDuration().String(conf.Retention)))
		}
	}

	if conf.AutoCreate {
		create.AllowAutoCreate(true)
	}

	if conf.Mode != "" {
		settings = settings.Mode(conf.Mode)
	}

	if len(mappings) > 0 {
		typemaps, err := modMappings(mappings)
		if err != nil {
			return err
		}

		maps.Mappings(typemaps)
	}

	if len(conf.Components) > 0 {
		create.ComposedOf(conf.Components...)
	}

	for _, alias := range conf.Aliases {
		maps.AddAlias(alias, esdsl.NewAlias())
	}

	if len(conf.Meta) > 0 {
		metadata, err := modMeta(conf, nil)
		if err != nil {
			return err
		}

		create.Meta_(esdsl.NewMetadata(metadata))
	}

	if len(conf.Settings) > 0 {
		usersettings, err := modSettings(conf)
		if err != nil {
			return err
		}

		settings = settings.IndexSettings(usersettings)
	}

	maps.Settings(settings)
	create.Template(maps)
	create.IndexPatterns(conf.Patterns...)

	_, err := create.Do(context.Background())
	if err != nil {
		return fmt.Errorf("failed to create index template: %w", esErrorString(err))
	}

	return nil
}

// FIXME: func's too long, refactor
// FIXME: it's not yet possible to remove items in lists (aliases, mappings, settings), just overwrite them
func IndexTemplateModify(conf *cfg.Config, name string, mappings []string) error {
	maps := esdsl.NewIndexTemplateMapping()

	// load existing index mapping
	res, err := conf.DefaultCluster.ES().Indices.GetIndexTemplate().
		Name(name).
		Do(context.Background())
	if err != nil {
		return fmt.Errorf("failed to get index template: %w", esErrorString(err))
	}

	slog.Debug("res", "index template", res)

	if len(res.IndexTemplates) != 1 {
		return errors.New("multiple or no index template matched the pattern")
	}

	tpl := res.IndexTemplates[0]

	// our modify PUT request
	modify := conf.DefaultCluster.ES().Indices.PutIndexTemplate(name)

	// load existing settings, if any
	settings := tpl.IndexTemplate.Template.Settings

	// pre fill mappings and aliases
	maps.Mappings(tpl.IndexTemplate.Template.Mappings)
	maps.Aliases(tpl.IndexTemplate.Template.Aliases)

	// pre fill components
	modify.ComposedOf(tpl.IndexTemplate.ComposedOf...)

	// pre fill data stream config
	if conf.Stream {
		modify.DataStream(esdsl.NewDataStreamVisibility())

		if conf.Retention != "" {
			maps.Lifecycle(
				esdsl.NewDataStreamLifecycle().
					DataRetention(
						esdsl.NewDuration().String(conf.Retention)))
		}
	}

	modify.AllowAutoCreate(conf.AutoCreate)

	if conf.Mode != "" {
		*settings.Mode = conf.Mode
	}

	if conf.Policy != "" {
		settings.Lifecycle.Name = &conf.Policy
	}

	if len(mappings) > 0 {
		typemaps, err := modMappings(mappings)
		if err != nil {
			return err
		}

		maps.Mappings(typemaps)
	}

	if len(conf.Components) > 0 {
		modify.ComposedOf(conf.Components...)
	}

	for _, alias := range conf.Aliases {
		maps.AddAlias(alias, esdsl.NewAlias())
	}

	if len(conf.Meta) > 0 {
		// pre fill meta, if any
		metadata, err := modMeta(conf, tpl.IndexTemplate.Meta_)
		if err != nil {
			return err
		}

		modify.Meta_(esdsl.NewMetadata(metadata))
	}

	if len(conf.Settings) > 0 {
		usersettings, err := modSettings(conf)
		if err != nil {
			return err
		}

		settings.IndexSettings = usersettings
	}

	patterns := tpl.IndexTemplate.IndexPatterns
	if len(conf.Patterns) > 0 {
		patterns = conf.Patterns
	}

	maps.Settings(settings)
	modify.Template(maps)
	modify.IndexPatterns(patterns...)

	_, err = modify.Do(context.Background())
	if err != nil {
		return fmt.Errorf("failed to modify index template: %w", esErrorString(err))
	}

	if conf.Rollover {
		if err := rolloverAliasIndexTemplate(conf, name); err != nil {
			return err
		}
	}

	return nil
}

func IndexTemplateDelete(conf *cfg.Config, name string) error {
	_, err := conf.DefaultCluster.ES().Indices.DeleteIndexTemplate(name).
		Do(context.Background())
	if err != nil {
		return fmt.Errorf("failed to delete index template: %w", esErrorString(err))
	}

	return nil
}

// Based on given  index template find the  associated index patterns,
// find  indices matching  those,  find their  associated aliases  and
// rollover all we find. Only run when conf.Rollover==true
func rolloverAliasIndexTemplate(conf *cfg.Config, name string) error {
	res, err := conf.DefaultCluster.ES().Indices.GetIndexTemplate().
		Name(name).
		Do(context.Background())
	if err != nil {
		return fmt.Errorf("failed to get index template: %w", esErrorString(err))
	}

	slog.Debug("res", "index template", res)

	if len(res.IndexTemplates) != 1 {
		return errors.New("multiple or no index template matched the pattern")
	}

	patterns := res.IndexTemplates[0].IndexTemplate.IndexPatterns
	aliases := map[string]int{}

	// find all aliases matching the patterns
	for _, pattern := range patterns {
		res, err := conf.DefaultCluster.ES().Indices.ResolveIndex(pattern).
			Do(context.Background())
		if err != nil {
			return fmt.Errorf("failed to resolve index pattern: %w", esErrorString(err))
		}

		for _, index := range res.Indices {
			for _, alias := range index.Aliases {
				aliases[alias] = 1
			}
		}
	}

	if len(aliases) == 0 {
		return nil
	}

	table := printer.NewTable(conf, 4, 0)
	table.Addheaders("rollover alias", "status", "ack", "new index")

	// apply rollover to all matching aliases, if any
	for alias := range aliases {
		res, err := RolloverAlias(conf, alias)
		if err != nil {
			return err
		}

		table.AddRow(alias, res.RolledOver, res.Acknowledged, res.NewIndex)

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

	return nil
}

func modMappings(mappings []string) (types.TypeMappingVariant, error) {
	typemaps := esdsl.NewTypeMapping()

	for _, mapping := range mappings {
		parts := strings.Split(mapping, ":")
		if len(parts) != 2 {
			return nil, fmt.Errorf(
				"invalid mapping %s, expect <name:type> (type: integer, text, date, keyword)",
				mapping)
		}

		switch parts[1] {
		case "text":
			typemaps.AddProperty(parts[0], esdsl.NewTextProperty())
		case "integer":
			typemaps.AddProperty(parts[0], esdsl.NewIntegerNumberProperty())
		case "date":
			typemaps.AddProperty(parts[0], esdsl.NewDateProperty())
		case "keyword":
			typemaps.AddProperty(parts[0], esdsl.NewKeywordProperty())
		}
	}

	return typemaps, nil
}

func modMeta(conf *cfg.Config, meta types.Metadata) (map[string]json.RawMessage, error) {
	metadata := map[string]json.RawMessage{}

	maps.Copy(metadata, meta)

	for _, meta := range conf.Meta {
		parts := strings.Split(meta, ":")
		if len(parts) != 2 {
			return nil, errors.New("meta data must be in the form key:value")
		}

		msg, err := json.Marshal(parts[1])
		if err != nil {
			return nil, fmt.Errorf("failed to json marshal metadata %s: %w", meta, err)
		}

		metadata[parts[0]] = msg
	}

	return metadata, nil
}

func modSettings(conf *cfg.Config) (map[string]json.RawMessage, error) {
	usersettings := map[string]json.RawMessage{}

	for _, meta := range conf.Settings {
		parts := strings.Split(meta, ":")
		if len(parts) != 2 {
			return nil, errors.New("settings data must be in the form key:value")
		}

		msg, err := json.Marshal(parts[1])
		if err != nil {
			return nil, fmt.Errorf("failed to json marshal metadata %s: %w", meta, err)
		}

		usersettings[parts[0]] = msg
	}

	return usersettings, nil
}