/**
 * Стратегии миграции конфигураций виджета чата
 */

import { DEFAULT_CONFIG } from '../default-config'
import { 
  MigrationStrategy, 
  MigrationContext, 
  MigrationStepResult, 
  ConfigV1
} from './types'

/** Базовый класс для стратегий миграции */
export abstract class BaseMigrationStrategy implements MigrationStrategy {
  abstract name: string
  abstract description: string
  abstract appliesTo: { from: any; to: any }

  canApply(context: MigrationContext): boolean {
    return context.fromVersion === this.appliesTo.from && 
           context.toVersion === this.appliesTo.to
  }

  abstract apply(context: MigrationContext): MigrationStepResult

  rollback?(_context: MigrationContext): MigrationStepResult {
    return {
      success: false,
      errors: [`Rollback not implemented for strategy: ${this.name}`],
      warnings: [],
      modified: false
    }
  }

  protected createSuccessResult(data: any, warnings: string[] = []): MigrationStepResult {
    return {
      success: true,
      data,
      errors: [],
      warnings,
      modified: true
    }
  }

  protected createErrorResult(errors: string[], data?: any): MigrationStepResult {
    return {
      success: false,
      data,
      errors,
      warnings: [],
      modified: false
    }
  }
}

/** Стратегия добавления новых полей в settings для V1->V2 */
export class AddSettingsFieldsV1toV2Strategy extends BaseMigrationStrategy {
  name = 'AddSettingsFieldsV1toV2'
  description = 'Добавляет новые поля loader, buttonStyle, buttonType в settings'
  appliesTo = { from: '1.0' as const, to: '2.0' as const }

  apply(context: MigrationContext): MigrationStepResult {
    try {
      const config = { ...context.config } as ConfigV1
      const warnings: string[] = []

      // Добавляем новые поля в settings
      const newSettings = {
        ...config.settings,
        loader: DEFAULT_CONFIG.settings.loader, // 'dots'
      }

      warnings.push(`Добавлены поля loader: '${newSettings.loader}'`)

      return this.createSuccessResult(
        { ...config, settings: newSettings },
        warnings
      )
    } catch (error) {
      return this.createErrorResult([`Ошибка при добавлении полей settings: ${error}`])
    }
  }
}

/** Стратегия добавления chipStyle в top.params для V1->V2 */
export class AddChipStyleV1toV2Strategy extends BaseMigrationStrategy {
  name = 'AddChipStyleV1toV2'
  description = 'Добавляет поле chipStyle в sections.top.params'
  appliesTo = { from: '1.0' as const, to: '2.0' as const }

  apply(context: MigrationContext): MigrationStepResult {
    try {
      const config = { ...context.config }
      const warnings: string[] = []

      // Добавляем chipStyle в top.params
      config.sections.top.params = {
        ...config.sections.top.params,
        chipStyle: DEFAULT_CONFIG.sections.top.params.chipStyle // 'filled'
      }

      warnings.push(`Добавлено поле chipStyle: '${DEFAULT_CONFIG.sections.top.params.chipStyle}' в sections.top.params`)

      return this.createSuccessResult(config, warnings)
    } catch (error) {
      return this.createErrorResult([`Ошибка при добавлении chipStyle: ${error}`])
    }
  }
}

/** Стратегия добавления bgType для сообщений в V1->V2 */
export class AddMessageBgTypeV1toV2Strategy extends BaseMigrationStrategy {
  name = 'AddMessageBgTypeV1toV2'
  description = 'Добавляет поле bgType в messageUser и messageBot'
  appliesTo = { from: '1.0' as const, to: '2.0' as const }

  apply(context: MigrationContext): MigrationStepResult {
    try {
      const config = { ...context.config }
      const warnings: string[] = []

      // Добавляем bgType в messageUser и messageBot
      config.sections.inside.messageUser = {
        ...config.sections.inside.messageUser,
        bgType: DEFAULT_CONFIG.sections.inside.messageUser.bgType // 'bubble'
      }

      config.sections.inside.messageBot = {
        ...config.sections.inside.messageBot,
        bgType: DEFAULT_CONFIG.sections.inside.messageBot.bgType // 'plain'
      }

      warnings.push('Добавлены поля bgType для messageUser и messageBot')

      return this.createSuccessResult(config, warnings)
    } catch (error) {
      return this.createErrorResult([`Ошибка при добавлении bgType для сообщений: ${error}`])
    }
  }
}

/** Стратегия добавления новых кнопок approve/reject в V1->V2 */
export class AddActionButtonsV1toV2Strategy extends BaseMigrationStrategy {
  name = 'AddActionButtonsV1toV2'
  description = 'Добавляет кнопки aprooveButton и rejectButton в inside секцию'
  appliesTo = { from: '1.0' as const, to: '2.0' as const }

  apply(context: MigrationContext): MigrationStepResult {
    try {
      const config = { ...context.config }
      const warnings: string[] = []

      // Добавляем новые кнопки
      config.sections.inside = {
        ...config.sections.inside
      }

      warnings.push('Добавлены кнопки aprooveButton и rejectButton')

      return this.createSuccessResult(config, warnings)
    } catch (error) {
      return this.createErrorResult([`Ошибка при добавлении кнопок действий: ${error}`])
    }
  }
}

/** Стратегия расширения inputSend для V1->V2 */
export class EnhanceInputSendV1toV2Strategy extends BaseMigrationStrategy {
  name = 'EnhanceInputSendV1toV2'
  description = 'Добавляет borderStyle, inputStyle, bgType в inputSend'
  appliesTo = { from: '1.0' as const, to: '2.0' as const }

  apply(context: MigrationContext): MigrationStepResult {
    try {
      const config = { ...context.config }
      const warnings: string[] = []

      // Расширяем inputSend
      config.sections.bottom.inputSend = {
        ...config.sections.bottom.inputSend,
        borderStyle: {
          borderColor: DEFAULT_CONFIG.sections.bottom.inputSend.borderColor,
          borderWidth: DEFAULT_CONFIG.sections.bottom.inputSend.borderWidth,
        },
        inputStyle: DEFAULT_CONFIG.sections.bottom.inputSend.inputStyle, // 'inside'
        bgType: DEFAULT_CONFIG.sections.bottom.inputSend.bgType // 'plain'
      }

      warnings.push('Расширен inputSend с новыми полями borderStyle, inputStyle, bgType')

      return this.createSuccessResult(config, warnings)
    } catch (error) {
      return this.createErrorResult([`Ошибка при расширении inputSend: ${error}`])
    }
  }
}

/** Стратегия добавления warningAlert и disclaimer в V1->V2 */
export class AddBottomElementsV1toV2Strategy extends BaseMigrationStrategy {
  name = 'AddBottomElementsV1toV2'
  description = 'Добавляет warningAlert и disclaimer в bottom секцию'
  appliesTo = { from: '1.0' as const, to: '2.0' as const }

  apply(context: MigrationContext): MigrationStepResult {
    try {
      const config = { ...context.config }
      const warnings: string[] = []

      // Добавляем новые элементы в bottom
      config.sections.bottom = {
        ...config.sections.bottom,
        // warningAlert: DEFAULT_CONFIG.sections.bottom.warningAlert
      }

      warnings.push('Добавлены warningAlert и disclaimer в bottom секцию')

      return this.createSuccessResult(config, warnings)
    } catch (error) {
      return this.createErrorResult([`Ошибка при добавлении элементов bottom: ${error}`])
    }
  }
}

/** Реестр всех стратегий миграции V1->V2 */
export const V1_TO_V2_STRATEGIES: MigrationStrategy[] = [
  new AddSettingsFieldsV1toV2Strategy(),
  new AddChipStyleV1toV2Strategy(),
  new AddMessageBgTypeV1toV2Strategy(),
  new AddActionButtonsV1toV2Strategy(),
  new EnhanceInputSendV1toV2Strategy(),
  new AddBottomElementsV1toV2Strategy()
]

/** Стратегия добавления theme и container в settings для V2->V3 */
export class AddThemeAndContainerV2toV3Strategy extends BaseMigrationStrategy {
  name = 'AddThemeAndContainerV2toV3'
  description = 'Adds theme and container (innerBorder, outerBorder, gradient) to settings'
  appliesTo = { from: '2.0' as const, to: '3.0' as const }

  apply(context: MigrationContext): MigrationStepResult {
    try {
      const config = { ...context.config }
      const warnings: string[] = []

      // Добавляем theme если его нет
      if (!config.settings.theme) {
        config.settings.theme = DEFAULT_CONFIG.settings.theme // 'auto'
        warnings.push(`Добавлено поле theme: '${config.settings.theme}'`)
      }

      // Добавляем container если его нет
      if (!config.settings.container) {
        config.settings.container = {
          innerBorder: {
            width: DEFAULT_CONFIG.settings.container?.innerBorder?.width || 0,
            color: DEFAULT_CONFIG.settings.container?.innerBorder?.color || 'transparent',
            style: DEFAULT_CONFIG.settings.container?.innerBorder?.style || 'solid',
          },
          outerBorder: {
            width: DEFAULT_CONFIG.settings.container?.outerBorder?.width || 0,
            color: DEFAULT_CONFIG.settings.container?.outerBorder?.color || 'transparent',
            style: DEFAULT_CONFIG.settings.container?.outerBorder?.style || 'solid',
          },
          gradient: DEFAULT_CONFIG.settings.container?.gradient || 'transparent',
        }
        warnings.push('Added container object with innerBorder, outerBorder, gradient')
      }

      // Конвертируем borderRadius из строки в число если нужно
      if (typeof config.settings.borderRadius === 'string') {
        const borderRadiusMap: Record<string, number> = {
          '0': 0,
          'sm': 4,
          'md': 8,
          'lg': 12,
        }
        config.settings.borderRadius = borderRadiusMap[config.settings.borderRadius] ?? 12
        warnings.push(`Конвертирован borderRadius из строки в число: ${config.settings.borderRadius}`)
      }

      return this.createSuccessResult(config, warnings)
    } catch (error) {
      return this.createErrorResult([`Ошибка при добавлении theme и container: ${error}`])
    }
  }
}

/** Стратегия добавления border, sideMargin, borderRadius в top.params для V2->V3 */
export class AddTopParamsV2toV3Strategy extends BaseMigrationStrategy {
  name = 'AddTopParamsV2toV3'
  description = 'Добавляет border, sideMargin, borderRadius в sections.top.params'
  appliesTo = { from: '2.0' as const, to: '3.0' as const }

  apply(context: MigrationContext): MigrationStepResult {
    try {
      const config = { ...context.config }
      const warnings: string[] = []

      if (!config.sections?.top?.params) {
        config.sections.top = config.sections.top || {}
        config.sections.top.params = {}
      }

      // Добавляем border если его нет
      if (!config.sections.top.params.border) {
        config.sections.top.params.border = {
          width: DEFAULT_CONFIG.sections.top.params.border?.width || 0,
          color: DEFAULT_CONFIG.sections.top.params.border?.color || 'transparent',
        }
        warnings.push('Добавлено поле border в sections.top.params')
      }

      // Добавляем sideMargin если его нет
      if (config.sections.top.params.sideMargin === undefined) {
        config.sections.top.params.sideMargin = DEFAULT_CONFIG.sections.top.params.sideMargin || 0
        warnings.push(`Добавлено поле sideMargin: ${config.sections.top.params.sideMargin}`)
      }

      // Добавляем borderRadius если его нет
      if (config.sections.top.params.borderRadius === undefined) {
        config.sections.top.params.borderRadius = DEFAULT_CONFIG.sections.top.params.borderRadius || 12
        warnings.push(`Добавлено поле borderRadius: ${config.sections.top.params.borderRadius}`)
      }

      return this.createSuccessResult(config, warnings)
    } catch (error) {
      return this.createErrorResult([`Ошибка при добавлении полей top.params: ${error}`])
    }
  }
}

/** Стратегия добавления dataAction в inside для V2->V3 */
export class AddDataActionV2toV3Strategy extends BaseMigrationStrategy {
  name = 'AddDataActionV2toV3'
  description = 'Добавляет dataAction в sections.inside'
  appliesTo = { from: '2.0' as const, to: '3.0' as const }

  apply(context: MigrationContext): MigrationStepResult {
    try {
      const config = { ...context.config }
      const warnings: string[] = []

      if (!config.sections?.inside) {
        config.sections.inside = {}
      }

      // Normalize dataAction to the V3 object shape (supports legacy string configs).
      const defaultDataActionRaw = (DEFAULT_CONFIG as any)?.sections?.inside?.dataAction
      const defaultDataAction =
        defaultDataActionRaw && typeof defaultDataActionRaw === 'object'
          ? defaultDataActionRaw
          : {
              type: 'steps',
              headerFillColor: '#595959',
              headerText: '#fff',
              bodyFillColor: '#595959',
              activeStepColor: '#fff',
              pastStepColor: '#fff',
              strokeColor: '#595959',
              strokeWidth: 0,
            }

      const cloneDefault = () => JSON.parse(JSON.stringify(defaultDataAction))

      const current = (config.sections.inside as any).dataAction
      if (!current) {
        ;(config.sections.inside as any).dataAction = cloneDefault()
        warnings.push(`Added dataAction object (type: '${(config.sections.inside as any).dataAction.type}')`)
      } else if (typeof current === 'string') {
        ;(config.sections.inside as any).dataAction = {
          ...cloneDefault(),
          type: current,
        }
        warnings.push(`Upgraded dataAction from string to object (type: '${current}')`)
      } else if (typeof current === 'object') {
        // Fill missing fields from defaults, but keep user's existing values.
        ;(config.sections.inside as any).dataAction = {
          ...cloneDefault(),
          ...current,
        }
        if (!(config.sections.inside as any).dataAction.type) {
          ;(config.sections.inside as any).dataAction.type = cloneDefault().type
          warnings.push(`Filled missing dataAction.type with default ('${(config.sections.inside as any).dataAction.type}')`)
        }
      }

      return this.createSuccessResult(config, warnings)
    } catch (error) {
      return this.createErrorResult([`Ошибка при добавлении dataAction: ${error}`])
    }
  }
}

/** Стратегия расширения welcomeMessage для V2->V3 */
export class EnhanceWelcomeMessageV2toV3Strategy extends BaseMigrationStrategy {
  name = 'EnhanceWelcomeMessageV2toV3'
  description = 'Расширяет welcomeMessage с borderColor и другими полями'
  appliesTo = { from: '2.0' as const, to: '3.0' as const }

  apply(context: MigrationContext): MigrationStepResult {
    try {
      const config = { ...context.config }
      const warnings: string[] = []

      if (!config.sections?.inside?.welcomeMessage) {
        config.sections.inside.welcomeMessage = {}
      }

      const welcomeMsg = config.sections.inside.welcomeMessage
      const defaultWelcome = DEFAULT_CONFIG.sections.inside.welcomeMessage

      // Добавляем недостающие поля
      if (!welcomeMsg.borderColor && defaultWelcome.borderColor) {
        welcomeMsg.borderColor = defaultWelcome.borderColor
        warnings.push(`Добавлено поле borderColor для welcomeMessage`)
      }

      if (!welcomeMsg.bgType && defaultWelcome.bgType) {
        welcomeMsg.bgType = defaultWelcome.bgType
        warnings.push(`Добавлено поле bgType для welcomeMessage: '${welcomeMsg.bgType}'`)
      }

      if (!welcomeMsg.bgColor && defaultWelcome.bgColor) {
        welcomeMsg.bgColor = defaultWelcome.bgColor
        warnings.push(`Добавлено поле bgColor для welcomeMessage`)
      }

      if (welcomeMsg.borderWidth === undefined && defaultWelcome.borderWidth !== undefined) {
        welcomeMsg.borderWidth = defaultWelcome.borderWidth
        warnings.push(`Добавлено поле borderWidth для welcomeMessage`)
      }

      if (!welcomeMsg.fontSize && defaultWelcome.fontSize) {
        welcomeMsg.fontSize = defaultWelcome.fontSize
        warnings.push(`Добавлено поле fontSize для welcomeMessage`)
      }

      if (!welcomeMsg.size && defaultWelcome.size) {
        welcomeMsg.size = defaultWelcome.size
        warnings.push(`Добавлено поле size для welcomeMessage`)
      }

      if (!welcomeMsg.borderRadius && defaultWelcome.borderRadius) {
        welcomeMsg.borderRadius = defaultWelcome.borderRadius
        warnings.push(`Добавлено поле borderRadius для welcomeMessage`)
      }

      return this.createSuccessResult(config, warnings)
    } catch (error) {
      return this.createErrorResult([`Ошибка при расширении welcomeMessage: ${error}`])
    }
  }
}

/** Стратегия добавления btnVoice в bottom для V2->V3 */
export class AddVoiceButtonV2toV3Strategy extends BaseMigrationStrategy {
  name = 'AddVoiceButtonV2toV3'
  description = 'Добавляет btnVoice в sections.bottom'
  appliesTo = { from: '2.0' as const, to: '3.0' as const }

  apply(context: MigrationContext): MigrationStepResult {
    try {
      const config = { ...context.config }
      const warnings: string[] = []

      if (!config.sections?.bottom) {
        config.sections.bottom = {}
      }

      // Добавляем btnVoice если его нет
      if (!config.sections.bottom.btnVoice) {
        config.sections.bottom.btnVoice = {
          color: DEFAULT_CONFIG.sections.bottom.btnVoice?.color || '#fff',
          bgColor: DEFAULT_CONFIG.sections.bottom.btnVoice?.bgColor || 'rgba(255, 255, 255, 0.10)',
          showType: DEFAULT_CONFIG.sections.bottom.btnVoice?.showType || 'icon',
          borderRadius: DEFAULT_CONFIG.sections.bottom.btnVoice?.borderRadius || 50,
          borderColor: DEFAULT_CONFIG.sections.bottom.btnVoice?.borderColor || '#595959',
          borderWidth: DEFAULT_CONFIG.sections.bottom.btnVoice?.borderWidth || 1,
          size: DEFAULT_CONFIG.sections.bottom.btnVoice?.size || 'md',
          fontSize: DEFAULT_CONFIG.sections.bottom.btnVoice?.fontSize || 12,
          icon: DEFAULT_CONFIG.sections.bottom.btnVoice?.icon || {
            showIcon: true,
            src: '<svg width="18" height="18" viewBox="0 0 18 18" fill="none" xmlns="http://www.w3.org/2000/svg"><path d="M9 1.5C8.20156 1.5 7.5 2.20156 7.5 3V9C7.5 9.79844 8.20156 10.5 9 10.5C9.79844 10.5 10.5 9.79844 10.5 9V3C10.5 2.20156 9.79844 1.5 9 1.5Z" fill="currentColor"/><path d="M13.5 7.5C13.0852 7.5 12.75 7.83516 12.75 8.25V9C12.75 10.2422 11.7422 11.25 10.5 11.25C9.25781 11.25 8.25 10.2422 8.25 9V8.25C8.25 7.83516 7.91484 7.5 7.5 7.5C7.08516 7.5 6.75 7.83516 6.75 8.25V9C6.75 10.8609 8.13906 12.375 9.9375 12.6562V14.25H7.5C7.08516 14.25 6.75 14.5852 6.75 15C6.75 15.4148 7.08516 15.75 7.5 15.75H10.5C10.9148 15.75 11.25 15.4148 11.25 15C11.25 14.5852 10.9148 14.25 10.5 14.25H10.3125V12.6562C12.1109 12.375 13.5 10.8609 13.5 9V8.25C13.5 7.83516 13.1648 7.5 12.75 7.5Z" fill="currentColor"/></svg>',
            color: '#fff',
            size: 18,
          },
        }
        if(!config.sections.bottom.btnVoice.bgColor) {
          config.sections.bottom.btnVoice.bgColor = DEFAULT_CONFIG.sections.bottom.btnVoice.bgColor
          warnings.push(`Добавлено поле bgColor для btnVoice: '${config.sections.bottom.btnVoice.bgColor}'`)
        }
        warnings.push('Добавлен btnVoice в sections.bottom')
      }

      return this.createSuccessResult(config, warnings)
    } catch (error) {
      return this.createErrorResult([`Ошибка при добавлении btnVoice: ${error}`])
    }
  }
}

/** Реестр всех стратегий миграции V2->V3 */
export const V2_TO_V3_STRATEGIES: MigrationStrategy[] = [
  new AddThemeAndContainerV2toV3Strategy(),
  new AddTopParamsV2toV3Strategy(),
  new AddDataActionV2toV3Strategy(),
  new EnhanceWelcomeMessageV2toV3Strategy(),
  new AddVoiceButtonV2toV3Strategy()
]

/** Получить все стратегии для конкретного перехода версий */
export function getStrategiesForMigration(from: string, to: string): MigrationStrategy[] {
  // Reuse V2->V3 strategies for any 3.0->3.1 hop to avoid empty step.
  if (from === '3.0' && to === '3.1') {
    return V2_TO_V3_STRATEGIES.map(strategy => {
      // Clone strategy to avoid mutating original appliesTo; preserve methods.
      const clone = Object.create(strategy) as MigrationStrategy
      clone.appliesTo = { from: '3.0' as const, to: '3.1' as const }
      return clone
    })
  }

  const allStrategies = [
    ...V1_TO_V2_STRATEGIES,
    ...V2_TO_V3_STRATEGIES
  ]

  return allStrategies.filter(strategy => 
    strategy.appliesTo.from === from && strategy.appliesTo.to === to
  )
}

/** Получить все доступные стратегии */
export function getAllStrategies(): MigrationStrategy[] {
  return [
    ...V1_TO_V2_STRATEGIES,
    ...V2_TO_V3_STRATEGIES
  ]
}