import type { Field } from '@/types/field'

/**
 * Total field stores summary UI and empty-state HTML in `htmlContent` as JSON.
 * Amounts are derived on the public form from all product × quantity pairs (form cart).
 */
export interface TotalFieldConfig {
  totalConfigVersion?: number
  enablePaymentSummary: boolean
  showPaymentSummaryCloseButton: boolean
  emptyPaymentMessageHtml: string
  enableAutocomplete: boolean
}

const CURRENT_CONFIG_VERSION = 1

const defaultConfig = (): TotalFieldConfig => ({
  totalConfigVersion: CURRENT_CONFIG_VERSION,
  enablePaymentSummary: false,
  showPaymentSummaryCloseButton: true,
  emptyPaymentMessageHtml: '',
  enableAutocomplete: false,
})

/** True only for boolean `true` or string `'true'` (JSON / loose storage must not coerce `"false"` to true). */
function parseBooleanStrict(value: unknown): boolean {
  return value === true || value === 'true'
}

export function parseTotalFieldConfig(field?: Field | null): TotalFieldConfig {
  if (!field) {
    return defaultConfig()
  }
  const blob = field.htmlContent
  if (typeof blob !== 'string' || blob.trim() === '') {
    return defaultConfig()
  }
  try {
    const parsed = JSON.parse(blob) as Record<string, unknown>
    const versionRaw = parsed['totalConfigVersion']
    const totalConfigVersion =
      typeof versionRaw === 'number' && Number.isFinite(versionRaw) ? versionRaw : 0

    const emptyRaw = parsed['emptyPaymentMessageHtml']
    const emptyPaymentMessageHtml =
      typeof emptyRaw === 'string' ? emptyRaw : defaultConfig().emptyPaymentMessageHtml

    const hasShowCloseButtonKey = Object.prototype.hasOwnProperty.call(
      parsed,
      'showPaymentSummaryCloseButton',
    )

    return {
      ...defaultConfig(),
      totalConfigVersion,
      enablePaymentSummary: parseBooleanStrict(parsed['enablePaymentSummary']),
      showPaymentSummaryCloseButton: hasShowCloseButtonKey
        ? parseBooleanStrict(parsed['showPaymentSummaryCloseButton'])
        : defaultConfig().showPaymentSummaryCloseButton,
      emptyPaymentMessageHtml,
      enableAutocomplete: parseBooleanStrict(parsed['enableAutocomplete']),
    }
  } catch {
    return defaultConfig()
  }
}

export function stringifyTotalFieldConfig(config: TotalFieldConfig): string {
  return JSON.stringify({
    totalConfigVersion: CURRENT_CONFIG_VERSION,
    enablePaymentSummary: config.enablePaymentSummary,
    showPaymentSummaryCloseButton: config.showPaymentSummaryCloseButton,
    emptyPaymentMessageHtml: config.emptyPaymentMessageHtml,
    enableAutocomplete: config.enableAutocomplete,
  })
}