import { createHash } from 'node:crypto'
import type { Db } from '@evofw/db'
import { repos } from '@evofw/db'
import { refreshAllHostnameRules } from '../policy/resolve-hostname.js'
import {
  findParentListIds,
  rebuildListCascade,
  rebuildManualListEntries,
} from './entries.js'
import { uniqCidrs } from '../uniq.js'
import { decryptSecret } from '../secret-cipher.js'

function hashCidrs(cidrs: string[]): string {
  return `sha256:${createHash('sha256').update(cidrs.join('\n')).digest('hex')}`
}

async function fetchJsonUrl(url: string): Promise<string[]> {
  const res = await fetch(url, {
    headers: { Accept: 'application/json' },
    signal: AbortSignal.timeout(30_000),
  })
  if (!res.ok) throw new Error(`JSON URL HTTP ${res.status}`)
  const data = (await res.json()) as unknown
  const out: string[] = []
  const push = (v: unknown) => {
    if (typeof v === 'string' && v.trim()) out.push(v.trim())
  }
  if (Array.isArray(data)) {
    for (const item of data) {
      if (typeof item === 'string') push(item)
      else if (item && typeof item === 'object') {
        const o = item as Record<string, unknown>
        push(o.cidr ?? o.prefix ?? o.ip ?? o.network)
      }
    }
  } else if (data && typeof data === 'object') {
    const o = data as Record<string, unknown>
    const arr = (o.prefixes ?? o.cidrs ?? o.ips ?? o.items) as unknown
    if (Array.isArray(arr)) {
      for (const item of arr) {
        if (typeof item === 'string') push(item)
        else if (item && typeof item === 'object') {
          const x = item as Record<string, unknown>
          push(x.cidr ?? x.prefix ?? x.ip)
        }
      }
    }
  }
  return uniqCidrs(out)
}

const UUID_RE =
  /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i

async function resolveEvobgpCommunityId(
  base: string,
  token: string,
  communityIdOrLabel: string,
): Promise<string> {
  const key = communityIdOrLabel.trim()
  if (!key) throw new Error('community_id required')
  if (UUID_RE.test(key)) return key

  // Heal lists created when Autocomplete stored label instead of UUID.
  const res = await fetch(`${base}/v1/communities?limit=200`, {
    headers: {
      Authorization: `Bearer ${token}`,
      Accept: 'application/json',
    },
    signal: AbortSignal.timeout(20_000),
  })
  if (!res.ok) {
    throw new Error(`EvoBGP communities HTTP ${res.status}`)
  }
  const data = (await res.json()) as {
    items?: { id?: string; community?: string; title?: string | null }[]
  }
  const hit = (data.items ?? []).find((c) => {
    if (!c.id || !c.community) return false
    if (c.id === key || c.community === key) return true
    if (c.title && `${c.community} · ${c.title}` === key) return true
    return false
  })
  if (!hit?.id) {
    throw new Error(`EvoBGP community not found: ${key}`)
  }
  return hit.id
}

async function fetchEvobgpCommunity(
  apiUrl: string,
  token: string,
  communityId: string,
): Promise<{ cidrs: string[]; resolvedId: string }> {
  const base = apiUrl.replace(/\/$/, '')
  const resolvedId = await resolveEvobgpCommunityId(base, token, communityId)
  const url = `${base}/v1/communities/${encodeURIComponent(resolvedId)}/prefixes?limit=5000`
  const res = await fetch(url, {
    headers: {
      Authorization: `Bearer ${token}`,
      Accept: 'application/json',
    },
    signal: AbortSignal.timeout(45_000),
  })
  if (!res.ok) {
    throw new Error(`EvoBGP community prefixes HTTP ${res.status}`)
  }
  const data = (await res.json()) as {
    items?: { prefix?: string }[]
    prefixes?: string[]
  }
  let cidrs: string[] = []
  if (Array.isArray(data.prefixes) && data.prefixes.length > 0) {
    cidrs = uniqCidrs(data.prefixes)
  } else if (Array.isArray(data.items)) {
    cidrs = uniqCidrs(data.items.map((i) => i.prefix ?? '').filter(Boolean))
  }
  return { cidrs, resolvedId }
}

export async function refreshIpList(db: Db, listId: string): Promise<void> {
  const list = repos.getIpList(db, listId)
  if (!list) return

  let config: Record<string, unknown> = {}
  try {
    config = JSON.parse(list.configJson || '{}') as Record<string, unknown>
  } catch {
    config = {}
  }

  try {
    let cidrs: string[] = []
    if (list.type === 'static' || list.type === 'domains') {
      cidrs = await rebuildManualListEntries(db, listId)
    } else if (list.type === 'json_url') {
      const url = String(config.url ?? '')
      if (!url) throw new Error('config.url required')
      cidrs = await fetchJsonUrl(url)
      repos.replaceIpListEntries(db, listId, cidrs)
    } else if (list.type === 'evobgp_community') {
      const apiUrl =
        String(config.api_url ?? '') ||
        repos.getSetting(db, 'evobgp_api_url') ||
        ''
      const token =
        decryptSecret(String(config.api_token ?? '') || null) ??
        decryptSecret(repos.getSetting(db, 'evobgp_api_token'))
      const communityId = String(config.community_id ?? '')
      if (!apiUrl || !token || !communityId) {
        throw new Error('evobgp_api_url, token and community_id required')
      }
      const fetched = await fetchEvobgpCommunity(apiUrl, token, communityId)
      cidrs = fetched.cidrs
      repos.replaceIpListEntries(db, listId, cidrs)
      // Persist resolved UUID if list was saved with autocomplete label.
      if (fetched.resolvedId !== communityId) {
        repos.updateIpList(db, listId, {
          configJson: JSON.stringify({
            ...config,
            community_id: fetched.resolvedId,
          }),
        })
      }
    }

    const contentHash = hashCidrs(cidrs)
    repos.updateIpList(db, listId, {
      contentHash,
      refreshedAt: new Date().toISOString(),
      lastError: null,
    })

    // Cascade to parents that nest this list (skip self rebuild for non-manual —
    // CIDRs already replaced above).
    if (list.type === 'static' || list.type === 'domains') {
      await rebuildListCascade(db, listId)
    } else {
      repos.bumpAgentsForList(db, listId)
      for (const parentId of findParentListIds(db, listId)) {
        await rebuildListCascade(db, parentId)
      }
    }
  } catch (err) {
    repos.updateIpList(db, listId, {
      lastError: err instanceof Error ? err.message : String(err),
      refreshedAt: new Date().toISOString(),
    })
  }
}

export async function refreshAllLists(db: Db): Promise<void> {
  for (const list of repos.listIpLists(db)) {
    await refreshIpList(db, list.id)
  }
  await refreshAllHostnameRules(db)
}