import { ref, toValue } from 'vue'
import { useApi } from '~/composables/useApi'
import type { MaybeRef } from 'vue'

export interface VersionEntry {
  version: number
  action: 'create' | 'update' | 'restore' | string
  createdAt: string
  actor: { id: string; label: string } | null
  diff: Record<string, { from: unknown; to: unknown }> | null
}

export interface RestorePreview {
  version: number
  restoreMode: 'full' | 'partial'
  diff: Record<string, { current: unknown; restored: unknown }>
  warnings: Array<{
    field: string
    message: string
    missingEntityId: string | null
    missingEntityName: string | null
  }>
  snapshot: Record<string, unknown>
}

export interface RestoreResult {
  success: boolean
  newVersion: number
  restoredFromVersion: number
  restoreMode: 'full' | 'partial'
  warnings: RestorePreview['warnings']
}

const ENTITY_ENDPOINTS: Record<string, string> = {
  machine: '/machines',
  composant: '/composants',
  piece: '/pieces',
  product: '/products',
}

interface Deps {
  entityType: MaybeRef<string>
  entityId: MaybeRef<string>
}

export function useEntityVersions(deps: Deps) {
  const { get, post } = useApi()

  const versions = ref<VersionEntry[]>([])
  const loading = ref(false)
  const error = ref<string | null>(null)

  const getPath = () => {
    const type = toValue(deps.entityType)
    const id = toValue(deps.entityId)
    const base = ENTITY_ENDPOINTS[type]
    return `${base}/${id}`
  }

  const fetchVersions = async () => {
    loading.value = true
    error.value = null
    try {
      const result = await get(`${getPath()}/versions`)
      if (!result.success) {
        error.value = result.error ?? 'Impossible de charger les versions.'
        versions.value = []
        return
      }
      versions.value = result.data?.items ?? []
    }
    catch (err: any) {
      error.value = err?.message ?? 'Erreur inconnue'
      versions.value = []
    }
    finally {
      loading.value = false
    }
  }

  const fetchPreview = async (version: number): Promise<RestorePreview | null> => {
    const result = await get<RestorePreview>(`${getPath()}/versions/${version}/preview`)
    if (!result.success || !result.data) {
      return null
    }
    return result.data
  }

  const restore = async (version: number): Promise<RestoreResult | null> => {
    const result = await post<RestoreResult>(`${getPath()}/versions/${version}/restore`, {})
    if (!result.success || !result.data) {
      return null
    }
    return result.data
  }

  return { versions, loading, error, fetchVersions, fetchPreview, restore }
}