// Package console holds the golem15.golem operator commands.
package console

import (
	"cmp"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"maps"
	"math"
	"os"
	"slices"
	"strconv"
	"strings"

	"git.golem15.com/golem15/sm-golem-plugin/models"
	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/bonfire"
	"git.golem15.com/golem15/summercms/modules/lagoon"
	"gorm.io/gorm"
)

// SettingsItem is the WinterCMS system_settings item that holds the
// plugin's AI models repeater.
const SettingsItem = "golem_settings"

// ImportSettings is golem:import-settings: a one-time copy of the
// WinterCMS plugin's AI models (the models repeater of the system_settings
// row golem_settings, or of a JSON file given with --file) into
// golem15_golem_models, in repeater order, each plaintext API key
// encrypted on write. It refuses to run when the table already has rows,
// so a second run changes nothing.
func ImportSettings(app *backpack.App) bonfire.Command {
	return bonfire.Command{
		Name:        "golem:import-settings",
		Description: "Import the AI models of a WinterCMS golem_settings row (or a JSON file) into golem15_golem_models, once.",
		Flags: []bonfire.Flag{{
			Name:        "file",
			Description: "A JSON file holding the settings value ({\"models\":[...]}) or the models list, read instead of system_settings",
		}},
		Run: func(ctx context.Context, in bonfire.Input, out bonfire.Output) error {
			if app == nil {
				return errors.New("golem:import-settings: app is nil")
			}
			db, ok := app.Lookup[*gorm.DB]()
			if !ok || db == nil {
				return errors.New("golem:import-settings: database is not configured")
			}
			file, _ := in.Flag("file")
			n, err := ImportModels(ctx, db, strings.TrimSpace(file))
			var notice *importNotice
			switch {
			case errors.As(err, &notice):
				out.Info(notice.msg)
				return nil
			case err != nil:
				out.Error(err.Error())
				return err
			}
			out.Success(fmt.Sprintf("Imported %d AI models.", n))
			return nil
		},
	}
}

// ErrModelsNotEmpty refuses an import into a table that already has rows.
var ErrModelsNotEmpty = errors.New("golem15_golem_models already has rows; nothing was imported")

// importNotice is a clean stop: there is nothing to import.
type importNotice struct{ msg string }

func (n *importNotice) Error() string { return n.msg }

// IsNothingToImport reports an import that stopped because the source
// holds nothing (no system_settings table, no golem_settings row, no
// models).
func IsNothingToImport(err error) bool {
	var n *importNotice
	return errors.As(err, &n)
}

// ImportModels runs the import and returns the number of models written.
// file, when not empty, is read instead of the system_settings row.
func ImportModels(ctx context.Context, db *gorm.DB, file string) (int, error) {
	var count int64
	if err := db.WithContext(ctx).Model(&models.AiModel{}).Count(&count).Error; err != nil {
		return 0, err
	}
	if count > 0 {
		return 0, ErrModelsNotEmpty
	}
	raw, err := settingsValue(ctx, db, file)
	if err != nil {
		return 0, err
	}
	items, err := repeaterItems(raw)
	if err != nil {
		return 0, err
	}
	if len(items) == 0 {
		return 0, &importNotice{msg: "The settings hold no AI models: nothing to import."}
	}
	err = lagoon.Transaction(ctx, db, func(ctx context.Context, tx *gorm.DB) error {
		for i, item := range items {
			row := modelFromItem(item)
			row.SortOrder = i
			if err := tx.WithContext(ctx).Create(&row).Error; err != nil {
				return err
			}
		}
		return nil
	})
	if err != nil {
		return 0, err
	}
	return len(items), nil
}

func settingsValue(ctx context.Context, db *gorm.DB, file string) ([]byte, error) {
	if file != "" {
		raw, err := os.ReadFile(file)
		if err != nil {
			return nil, fmt.Errorf("golem:import-settings: read %s: %w", file, err)
		}
		return raw, nil
	}
	if !db.WithContext(ctx).Migrator().HasTable("system_settings") {
		return nil, &importNotice{msg: "No system_settings table: nothing to import."}
	}
	var values []string
	if err := db.WithContext(ctx).Raw(`SELECT value FROM system_settings WHERE item = ?`, SettingsItem).Scan(&values).Error; err != nil {
		return nil, err
	}
	if len(values) == 0 {
		return nil, &importNotice{msg: "No golem_settings row in system_settings: nothing to import."}
	}
	return []byte(values[0]), nil
}

// repeaterItems reads the models list of a settings value
// ({"models":[...]}) or a bare list.
func repeaterItems(raw []byte) ([]map[string]any, error) {
	var v any
	if err := json.Unmarshal(raw, &v); err != nil {
		return nil, fmt.Errorf("golem:import-settings: the settings are not JSON: %w", err)
	}
	if m, ok := v.(map[string]any); ok {
		v = m["models"]
	}
	var list []any
	switch t := v.(type) {
	case []any:
		list = t
	case map[string]any:
		// A repeater saved with non-sequential keys decodes as an object
		// ({"0":…,"2":…} after a middle item was deleted). Every key is
		// read, numeric keys in ascending order, then any other key.
		for _, k := range repeaterKeys(t) {
			list = append(list, t[k])
		}
	case nil:
	default:
		return nil, errors.New("golem:import-settings: models is not a list")
	}
	out := make([]map[string]any, 0, len(list))
	for _, item := range list {
		if m, ok := item.(map[string]any); ok {
			out = append(out, m)
		}
	}
	return out, nil
}

// repeaterKeys orders an object repeater's keys: integers ascending by
// value first, then the other keys in byte order.
func repeaterKeys(t map[string]any) []string {
	keys := slices.Collect(maps.Keys(t))
	slices.SortFunc(keys, func(a, b string) int {
		ai, aerr := strconv.Atoi(a)
		bi, berr := strconv.Atoi(b)
		switch {
		case aerr == nil && berr == nil:
			return cmp.Compare(ai, bi)
		case aerr == nil:
			return -1
		case berr == nil:
			return 1
		}
		return strings.Compare(a, b)
	})
	return keys
}

func modelFromItem(item map[string]any) models.AiModel {
	row := models.AiModel{
		Name:             str(item["name"]),
		Adapter:          str(item["adapter"]),
		Model:            str(item["model"]),
		IsEnabled:        truthy(item["is_enabled"]),
		IsDefault:        truthy(item["is_default"]),
		GeneratesImages:  truthy(item["generates_images"]),
		AcceptsImages:    truthy(item["accepts_images"]),
		HasFilesEndpoint: truthy(item["has_files_endpoint"]),
	}
	if row.Adapter == "" {
		row.Adapter = "openai"
	}
	if key := str(item["api_key"]); key != "" {
		row.APIKey = lagoon.NewEncrypted(key)
	}
	if s := str(item["base_url"]); s != "" {
		row.BaseURL = &s
	}
	if s := str(item["system_prompt"]); s != "" {
		row.SystemPrompt = &s
	}
	if n, ok := integer(item["max_completion_tokens"]); ok {
		row.MaxCompletionTokens = &n
	}
	return row
}

func str(v any) string {
	switch t := v.(type) {
	case string:
		return t
	case float64:
		return strconv.FormatFloat(t, 'f', -1, 64)
	case bool:
		if t {
			return "1"
		}
	}
	return ""
}

// truthy is PHP's truthiness of a stored switch ("1", true, 1).
func truthy(v any) bool {
	switch t := v.(type) {
	case bool:
		return t
	case string:
		return t != "" && t != "0"
	case float64:
		return t != 0
	}
	return false
}

func integer(v any) (int, bool) {
	switch t := v.(type) {
	case float64:
		if t == math.Trunc(t) {
			return int(t), true
		}
	case string:
		if n, err := strconv.Atoi(strings.TrimSpace(t)); err == nil {
			return n, true
		}
	}
	return 0, false
}