package main

import (
	"errors"
	"regexp"
	"strconv"
	"strings"
)

type keycloakThemeField struct {
	Name     string
	Type     string
	Required bool
	Options  []string
	Min      float64
	Max      float64
}

var keycloakThemeColorPattern = regexp.MustCompile(`^#[0-9a-fA-F]{6}$`)

var keycloakThemeFields = []keycloakThemeField{
	{Name: "logoAssetId", Type: "image"},
	{Name: "faviconAssetId", Type: "image"},
	{Name: "logoAssetMimeType", Type: "text"},
	{Name: "faviconAssetMimeType", Type: "text"},
	{Name: "primaryColor", Type: "color", Required: true},
	{Name: "secondaryColor", Type: "color"},
	{Name: "backgroundColor", Type: "color"},
	{Name: "textColor", Type: "color"},
	{Name: "buttonRadius", Type: "number", Min: 0, Max: 32},
	{Name: "fontFamily", Type: "select", Options: []string{"Inter", "System UI", "Roboto", "Open Sans", "Lato", "Montserrat"}},
	{Name: "loginHeading", Type: "text"},
	{Name: "loginSubheading", Type: "textarea"},
	{Name: "loginHelpText", Type: "textarea"},
	{Name: "registrationHeading", Type: "text"},
	{Name: "forgotPasswordHelpText", Type: "textarea"},
	{Name: "accountConsoleHeading", Type: "text"},
	{Name: "emailTemplateFooter", Type: "textarea"},
	{Name: "supportUrl", Type: "url"},
	{Name: "privacyUrl", Type: "url"},
	{Name: "termsUrl", Type: "url"},
	{Name: "footerText", Type: "textarea"},
	{Name: "securityText", Type: "textarea"},
}

var keycloakThemeFieldNames = func() map[string]struct{} {
	fields := map[string]struct{}{}
	for _, field := range keycloakThemeFields {
		fields[field.Name] = struct{}{}
	}
	return fields
}()

var keycloakThemeAllowedSystemMetadata = map[string]struct{}{
	"updatedBy":        {},
	"updatedAt":        {},
	"createdBy":        {},
	"createdAt":        {},
	"platformApproval": {},
	"exportRequested":  {},
}

var keycloakThemeDefaultFormValues = Doc{
	"primaryColor":        "#4f46e5",
	"backgroundColor":     "#ffffff",
	"textColor":           "#0f172a",
	"fontFamily":          "Inter",
	"buttonRadius":        8,
	"loginHeading":        "Welcome back",
	"registrationHeading": "Create your account",
	"footerText":          "Powered by CMS Platform",
	"securityText":        "Never share your password with anyone.",
}

func keycloakThemeFormSchemaSections() []Doc {
	return []Doc{
		{
			"id":    "brand",
			"title": "Brand",
			"fields": []Doc{
				{"type": "image", "name": "logoAssetId", "label": "Logo", "required": false},
				{"type": "image", "name": "faviconAssetId", "label": "Favicon", "required": false},
				{"type": "text", "name": "logoAssetMimeType", "label": "Logo MIME type", "required": false},
				{"type": "text", "name": "faviconAssetMimeType", "label": "Favicon MIME type", "required": false},
				{"type": "color", "name": "primaryColor", "label": "Primary colour", "required": true},
				{"type": "color", "name": "secondaryColor", "label": "Secondary colour", "required": false},
				{"type": "color", "name": "backgroundColor", "label": "Background colour", "required": false},
				{"type": "color", "name": "textColor", "label": "Text colour", "required": false},
				{"type": "select", "name": "fontFamily", "label": "Font family", "required": false, "options": []string{"Inter", "System UI", "Roboto", "Open Sans", "Lato", "Montserrat"}},
				{"type": "number", "name": "buttonRadius", "label": "Button radius", "required": false},
			},
		},
		{
			"id":    "authCopy",
			"title": "Authentication copy",
			"fields": []Doc{
				{"type": "text", "name": "loginHeading", "label": "Login heading", "required": false},
				{"type": "textarea", "name": "loginSubheading", "label": "Login subheading", "required": false},
				{"type": "textarea", "name": "loginHelpText", "label": "Login help text", "required": false},
				{"type": "text", "name": "registrationHeading", "label": "Registration heading", "required": false},
				{"type": "textarea", "name": "forgotPasswordHelpText", "label": "Forgot password help", "required": false},
			},
		},
		{
			"id":    "accountAndEmail",
			"title": "Account and email templates",
			"fields": []Doc{
				{"type": "text", "name": "accountConsoleHeading", "label": "Account console heading", "required": false},
				{"type": "textarea", "name": "emailTemplateFooter", "label": "Email footer text", "required": false},
			},
		},
		{
			"id":    "linksAndLegal",
			"title": "Links and legal",
			"fields": []Doc{
				{"type": "url", "name": "supportUrl", "label": "Support URL", "required": false},
				{"type": "url", "name": "privacyUrl", "label": "Privacy URL", "required": false},
				{"type": "url", "name": "termsUrl", "label": "Terms URL", "required": false},
				{"type": "textarea", "name": "footerText", "label": "Footer text", "required": false},
				{"type": "textarea", "name": "securityText", "label": "Security text", "required": false},
			},
		},
	}
}

func ensureThemeMetadataDefaults(doc Doc) {
	metadata := resolveThemeMetadata(nil, doc)
	if metadata == nil {
		metadata = Doc{}
	}
	for key, value := range keycloakThemeDefaultFormValues {
		if _, exists := metadata[key]; !exists {
			metadata[key] = value
		}
	}
	doc["metadata"] = metadata
}

func validateKeycloakThemeFormValues(metadata Doc) error {
	if metadata == nil {
		metadata = Doc{}
	}

	fieldMap := map[string]keycloakThemeField{}
	for _, field := range keycloakThemeFields {
		fieldMap[field.Name] = field
	}

	for key, value := range metadata {
		field, ok := fieldMap[key]
		if !ok {
			if _, allowed := keycloakThemeAllowedSystemMetadata[key]; allowed {
				continue
			}
			return errors.New("theme schema validation failed: unknown field " + key)
		}
		if err := validateThemeFieldValue(field, value); err != nil {
			return err
		}
	}

	for _, field := range keycloakThemeFields {
		if !field.Required {
			continue
		}
		value, exists := metadata[field.Name]
		if !exists || isEmptyThemeValue(value) {
			return errors.New("theme schema validation failed: required field " + field.Name + " is missing")
		}
	}

	return nil
}

func validateThemeFieldValue(field keycloakThemeField, value any) error {
	if isEmptyThemeValue(value) {
		if field.Required {
			return errors.New("theme schema validation failed: required field " + field.Name + " is missing")
		}
		return nil
	}

	switch field.Type {
	case "text", "textarea", "image":
		str, ok := value.(string)
		if !ok {
			return errors.New("theme schema validation failed: field " + field.Name + " must be a string")
		}
		trimmed := strings.TrimSpace(str)
		if field.Type == "image" && strings.Contains(trimmed, " ") {
			return errors.New("theme schema validation failed: image field " + field.Name + " must not contain spaces")
		}
	case "color":
		str, ok := value.(string)
		if !ok || !keycloakThemeColorPattern.MatchString(strings.TrimSpace(str)) {
			return errors.New("theme schema validation failed: field " + field.Name + " must be a hex color")
		}
	case "url":
		str, ok := value.(string)
		if !ok {
			return errors.New("theme schema validation failed: field " + field.Name + " must be a string")
		}
		if strings.TrimSpace(str) != "" {
			if err := validateThemeURL(str); err != nil {
				return errors.New("theme schema validation failed: field " + field.Name + " must be a valid URL")
			}
		}
	case "number":
		number, ok := normalizeThemeNumber(value)
		if !ok {
			return errors.New("theme schema validation failed: field " + field.Name + " must be a number")
		}
		if field.Min != 0 || field.Max != 0 {
			if number < field.Min || number > field.Max {
				return errors.New("theme schema validation failed: field " + field.Name + " is out of range")
			}
		}
	case "select":
		str, ok := value.(string)
		if !ok {
			return errors.New("theme schema validation failed: field " + field.Name + " must be a string")
		}
		if len(field.Options) == 0 {
			return nil
		}
		trimmed := strings.TrimSpace(str)
		for _, option := range field.Options {
			if option == trimmed {
				return nil
			}
		}
		return errors.New("theme schema validation failed: field " + field.Name + " has an unsupported value")
	}

	return nil
}

func normalizeThemeNumber(value any) (float64, bool) {
	switch v := value.(type) {
	case float64:
		return v, true
	case float32:
		return float64(v), true
	case int:
		return float64(v), true
	case int32:
		return float64(v), true
	case int64:
		return float64(v), true
	case string:
		parsed, err := strconv.ParseFloat(strings.TrimSpace(v), 64)
		if err != nil {
			return 0, false
		}
		return parsed, true
	default:
		return 0, false
	}
}

func isEmptyThemeValue(value any) bool {
	if value == nil {
		return true
	}
	if str, ok := value.(string); ok {
		return strings.TrimSpace(str) == ""
	}
	return false
}

func isKeycloakThemeSchemaField(name string) bool {
	_, exists := keycloakThemeFieldNames[name]
	return exists
}