package dashboard

import (
	"encoding/json"
	"errors"
	"fmt"
	"regexp"
)

const CurrentSchemaVersion = 2

var slugPattern = regexp.MustCompile("^[a-z0-9]+(?:-[a-z0-9]+)*$")

type Document map[string]any

func Validate(document Document) error {
	if document == nil {
		return errors.New("dashboard document is required")
	}
	if version, ok := number(document["schemaVersion"]); !ok || version < 1 || version > CurrentSchemaVersion {
		return errors.New("unsupported dashboard schema version")
	}
	for _, field := range []string{"id", "slug", "name", "scope", "variables", "widgets", "settings"} {
		if _, ok := document[field]; !ok {
			return fmt.Errorf("dashboard field %q is required", field)
		}
	}
	slug, ok := document["slug"].(string)
	if !ok || !slugPattern.MatchString(slug) || len(slug) > 80 {
		return errors.New("invalid dashboard slug")
	}
	name, ok := document["name"].(string)
	if !ok || name == "" || len(name) > 120 {
		return errors.New("invalid dashboard name")
	}
	scope, ok := document["scope"].(string)
	if !ok || scope != "personal" && scope != "shared" && scope != "system" {
		return errors.New("invalid dashboard scope")
	}
	if _, ok := document["widgets"].([]any); !ok {
		return errors.New("dashboard widgets must be an array")
	}
	if _, ok := document["variables"].([]any); !ok {
		return errors.New("dashboard variables must be an array")
	}
	if _, ok := document["settings"].(map[string]any); !ok {
		return errors.New("dashboard settings must be an object")
	}
	return nil
}

func Migrate(document Document) (Document, error) {
	if err := Validate(document); err != nil {
		return nil, err
	}
	version, _ := number(document["schemaVersion"])
	if version == CurrentSchemaVersion {
		return clone(document), nil
	}
	migrated := clone(document)
	migrated["schemaVersion"] = CurrentSchemaVersion
	settings := migrated["settings"].(map[string]any)
	if _, ok := settings["live"]; !ok {
		settings["live"] = false
	}
	if _, ok := settings["refreshSeconds"]; !ok {
		settings["refreshSeconds"] = 30
	}
	return migrated, nil
}
func clone(document Document) Document {
	encoded, _ := json.Marshal(document)
	var result Document
	_ = json.Unmarshal(encoded, &result)
	return result
}
func number(value any) (int, bool) {
	switch v := value.(type) {
	case int:
		return v, true
	case float64:
		return int(v), v == float64(int(v))
	default:
		return 0, false
	}
}