export type ThemeFieldType = 'text' | 'textarea' | 'url' | 'number' | 'select' | 'color' | 'image'

export type ThemeFieldSchema = {
  type: ThemeFieldType
  name: string
  label: string
  required?: boolean
  options?: string[]
}

export type ThemeSectionSchema = {
  id: string
  title: string
  fields: ThemeFieldSchema[]
}

const HEX_COLOR_PATTERN = /^#[0-9a-fA-F]{6}$/

const UNSAFE_TOKENS = ['<script', '</script', 'javascript:', 'onerror=', 'onload=', '<iframe', 'srcdoc=', 'data:text/html', 'vbscript:']

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

export const DEFAULT_THEME_FORM_VALUES: Record<string, string | number | boolean> = {
  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.',
}

export type ThemeFormValidationResult = {
  valid: boolean
  errors: Record<string, string>
}

function hasUnsafeToken(value: string): boolean {
  const normalized = value.toLowerCase()
  return UNSAFE_TOKENS.some(token => normalized.includes(token))
}

function isValidUrl(value: string): boolean {
  try {
    const parsed = new URL(value)
    return parsed.protocol === 'http:' || parsed.protocol === 'https:'
  } catch {
    return false
  }
}

export function validateThemeFormValues(
  schema: ThemeSectionSchema[],
  values: Record<string, unknown>,
): ThemeFormValidationResult {
  const errors: Record<string, string> = {}

  for (const section of schema) {
    for (const field of section.fields) {
      const value = values[field.name]
      const textValue = typeof value === 'string' ? value.trim() : ''

      if (field.required && (value === undefined || value === null || textValue === '')) {
        errors[field.name] = `${field.label} is required`
        continue
      }

      if (value === undefined || value === null || textValue === '') {
        continue
      }

      if (typeof value === 'string' && hasUnsafeToken(value)) {
        errors[field.name] = `${field.label} contains unsafe content`
        continue
      }

      if (field.type === 'color' && typeof value === 'string' && !HEX_COLOR_PATTERN.test(value.trim())) {
        errors[field.name] = `${field.label} must be a hex color`
        continue
      }

      if (field.type === 'url' && typeof value === 'string' && !isValidUrl(value.trim())) {
        errors[field.name] = `${field.label} must be a valid URL`
        continue
      }

      if (field.type === 'number') {
        const numeric = typeof value === 'number' ? value : Number(value)
        if (Number.isNaN(numeric)) {
          errors[field.name] = `${field.label} must be a number`
          continue
        }
      }

      if (field.type === 'select' && field.options && !field.options.includes(String(value).trim())) {
        errors[field.name] = `${field.label} has an unsupported value`
        continue
      }

      if (field.type === 'image' && typeof value === 'string' && value.includes(' ')) {
        errors[field.name] = `${field.label} must not contain spaces`
      }
    }
  }

  return {
    valid: Object.keys(errors).length === 0,
    errors,
  }
}