import { RecallBackup } from '@/types/backup'

interface ValidationResult {
  valid: boolean
  errors: string[]
  info?: {
    noteCount: number
    tagCount: number
    createdAt: string
    source: string
  }
}

export function validateBackup(data: unknown): ValidationResult {
  const errors: string[] = []

  if (typeof data !== 'object' || data === null) {
    return { valid: false, errors: ['Backup must be an object'] }
  }

  const backup = data as Record<string, unknown>

  if (!validateSchemaVersion(backup as unknown as RecallBackup)) {
    errors.push('Missing or invalid schemaVersion (expected "1.0")')
  }

  if (!backup.createdAt || typeof backup.createdAt !== 'string') {
    errors.push('Missing or invalid createdAt field')
  }

  if (!backup.source || typeof backup.source !== 'string') {
    errors.push('Missing or invalid source field')
  }

  if (!backup.metadata || typeof backup.metadata !== 'object') {
    errors.push('Missing or invalid metadata field')
  } else {
    const metadata = backup.metadata as Record<string, unknown>
    if (typeof metadata.noteCount !== 'number') {
      errors.push('Missing or invalid metadata.noteCount')
    }
    if (typeof metadata.tagCount !== 'number') {
      errors.push('Missing or invalid metadata.tagCount')
    }
  }

  if (!backup.data || typeof backup.data !== 'object') {
    errors.push('Missing or invalid data field')
  } else {
    const data = backup.data as Record<string, unknown>
    if (!Array.isArray(data.notes)) {
      errors.push('Missing or invalid data.notes (expected array)')
    }
  }

  if (errors.length > 0) {
    return { valid: false, errors }
  }

  const metadata = backup.metadata as { noteCount: number; tagCount: number }
  return {
    valid: true,
    errors: [],
    info: {
      noteCount: metadata.noteCount,
      tagCount: metadata.tagCount,
      createdAt: backup.createdAt as string,
      source: backup.source as string,
    },
  }
}

export function validateSchemaVersion(backup: RecallBackup): boolean {
  return backup.schemaVersion === '1.0'
}