import { eq } from "drizzle-orm"
import { db } from "../db/index.js"
import { servers } from "../db/schema.js"
import { MikrotikClient } from "./mikrotik.js"
import {
  canonicalGreSnapshot,
  type GreLiveAddr,
  type GreLiveIface,
  type GreSnapshot,
} from "./entity-snapshots.js"
import { captureAndAppendRevision } from "./config-revisions.js"

type ServerRow = typeof servers.$inferSelect

export interface RosGre {
  ".id"?: string
  name?: string
  "local-address"?: string
  "remote-address"?: string
  "allow-fast-path"?: string
  "clamp-tcp-mss"?: string
  mtu?: string
  keepalive?: string
  dscp?: string
  running?: string
  disabled?: string
  comment?: string
  "ipsec-secret"?: string
}

interface RosIpAddress {
  ".id"?: string
  address?: string
  interface?: string
  disabled?: string
  network?: string
}

export interface LiveGreTunnel {
  id: string
  rosId: string
  name: string
  serverId: string
  localAddress: string
  remoteAddress: string
  localInnerIp: string
  remoteInnerIp: string
  poolId: string
  ipsec: { secret: string } | null
  mtu: number
  keepaliveInterval: number
  keepaliveRetries: number
  dscp: "inherit" | number
  clampTcpMss: boolean
  allowFastPath: boolean
  comment: string
  enabled: boolean
  status: "up" | "down" | "degraded"
}

export function parseKeepalive(value: string | undefined): { interval: number; retries: number } {
  if (!value || value.toLowerCase() === "none") return { interval: 0, retries: 0 }
  const [intervalRaw, retriesRaw] = value.split(",")
  const interval = Number.parseInt((intervalRaw ?? "").trim(), 10)
  const retries = Number.parseInt((retriesRaw ?? "").trim(), 10)
  return {
    interval: Number.isFinite(interval) ? interval : 0,
    retries: Number.isFinite(retries) ? retries : 0,
  }
}

export function formatKeepalive(interval: number, retries: number): string {
  if (!interval || interval <= 0) return "0"
  return `${interval}s,${retries > 0 ? retries : 10}`
}

function parseDscp(value: string | undefined): "inherit" | number {
  if (!value || value === "inherit") return "inherit"
  const n = Number.parseInt(value, 10)
  return Number.isFinite(n) ? n : "inherit"
}

function parseInnerFromComment(comment: string | undefined): { localInnerIp: string; remoteInnerIp: string } {
  if (!comment) return { localInnerIp: "", remoteInnerIp: "" }
  const local = comment.match(/address\s*=\s*([0-9.]+\/\d+)/)?.[1] ?? ""
  const remote = comment.match(/(?:network|gateway)\s*=\s*([0-9.]+\/\d+)/)?.[1] ?? ""
  return { localInnerIp: local, remoteInnerIp: remote }
}

function rosDisabled(v: string | undefined): boolean {
  return v === "true" || v === "yes"
}

export function mapGreLive(
  server: ServerRow,
  greRaw: RosGre[],
  addrsRaw: RosIpAddress[],
): {
  tunnels: LiveGreTunnel[]
  snapshot: GreSnapshot
  gre: GreLiveIface[]
  addrs: GreLiveAddr[]
} {
  const addrsByIface = new Map<string, { address: string; rosId: string }[]>()
  for (const a of addrsRaw) {
    if (rosDisabled(a.disabled)) continue
    const iface = (a.interface ?? "").trim()
    const address = (a.address ?? "").trim()
    const rosId = String(a[".id"] ?? "")
    if (!iface || !address || !rosId) continue
    const list = addrsByIface.get(iface) ?? []
    list.push({ address, rosId })
    addrsByIface.set(iface, list)
  }

  const gre: GreLiveIface[] = []
  const addrs: GreLiveAddr[] = []
  const tunnels: LiveGreTunnel[] = []

  greRaw.forEach((g, idx) => {
    const rosId = String(g[".id"] ?? g.name ?? `gre-${idx}`)
    const name = (g.name ?? "").trim() || `gre-${idx + 1}`
    const keepalive = parseKeepalive(g.keepalive)
    const fromComment = parseInnerFromComment(g.comment)
    const ifaceAddrs = addrsByIface.get(name) ?? []
    const localInnerIp = ifaceAddrs[0]?.address || fromComment.localInnerIp
    const secret = (g["ipsec-secret"] ?? "").trim()
    const disabled = rosDisabled(g.disabled)
    const running = g.running === "true" || g.running === "yes"

    gre.push({
      name,
      rosId,
      localAddress: g["local-address"] ?? "",
      remoteAddress: g["remote-address"] ?? "",
      comment: g.comment ?? "",
      disabled,
      mtu: Number.parseInt(g.mtu ?? "1476", 10) || 1476,
      keepalive: g.keepalive ?? "0",
      dscp: g.dscp ?? "inherit",
      clampTcpMss: g["clamp-tcp-mss"] !== "false" && g["clamp-tcp-mss"] !== "no",
      allowFastPath: g["allow-fast-path"] !== "false" && g["allow-fast-path"] !== "no",
      ipsecSecret: secret,
    })

    for (const a of ifaceAddrs) {
      addrs.push({ rosId: a.rosId, interfaceName: name, address: a.address })
    }

    tunnels.push({
      id: rosId || `${server.id}:${name}`,
      rosId,
      name,
      serverId: String(server.id),
      localAddress: g["local-address"] ?? "",
      remoteAddress: g["remote-address"] ?? "",
      localInnerIp,
      remoteInnerIp: fromComment.remoteInnerIp,
      poolId: "live",
      ipsec: secret ? { secret } : null,
      mtu: Number.parseInt(g.mtu ?? "1476", 10) || 1476,
      keepaliveInterval: keepalive.interval,
      keepaliveRetries: keepalive.retries,
      dscp: parseDscp(g.dscp),
      clampTcpMss: g["clamp-tcp-mss"] !== "false" && g["clamp-tcp-mss"] !== "no",
      allowFastPath: g["allow-fast-path"] !== "false" && g["allow-fast-path"] !== "no",
      comment: g.comment ?? "",
      enabled: !disabled,
      status: disabled ? "down" : running ? "up" : "degraded",
    })
  })

  return {
    tunnels,
    snapshot: canonicalGreSnapshot({
      tunnels: gre.map((g) => ({
        name: g.name,
        localAddress: g.localAddress,
        remoteAddress: g.remoteAddress,
        localInnerIp: addrs.find((a) => a.interfaceName === g.name)?.address ?? "",
        remoteInnerIp: "",
        comment: g.comment,
        disabled: g.disabled,
        mtu: g.mtu,
        keepalive: g.keepalive,
        dscp: g.dscp,
        clampTcpMss: g.clampTcpMss,
        allowFastPath: g.allowFastPath,
        ipsecSecret: g.ipsecSecret,
      })),
    }),
    gre,
    addrs,
  }
}

export async function fetchGreState(server: ServerRow) {
  const client = MikrotikClient.fromServer(server)
  const [greRaw, addrsRaw] = await Promise.all([
    client.get<RosGre[]>("/interface/gre"),
    client.get<RosIpAddress[]>("/ip/address").catch(() => [] as RosIpAddress[]),
  ])
  return {
    client,
    ...mapGreLive(server, Array.isArray(greRaw) ? greRaw : [], Array.isArray(addrsRaw) ? addrsRaw : []),
  }
}

export async function captureGreSnapshot(server: ServerRow): Promise<GreSnapshot> {
  const state = await fetchGreState(server)
  return state.snapshot
}

export async function listGreTunnels(opts?: { serverId?: string }): Promise<{
  tunnels: LiveGreTunnel[]
  failures: Array<{ serverId: string; serverName?: string; error: string }>
}> {
  let serverRows: ServerRow[]
  if (opts?.serverId) {
    const id = Number.parseInt(String(opts.serverId), 10)
    if (!Number.isFinite(id)) {
      return { tunnels: [], failures: [{ serverId: String(opts.serverId), error: "Некорректный serverId" }] }
    }
    const row = (await db.select().from(servers).where(eq(servers.id, id)).limit(1))[0]
    serverRows = row ? [row] : []
  } else {
    serverRows = await db.select().from(servers).where(eq(servers.enabled, true))
  }

  const failures: Array<{ serverId: string; serverName?: string; error: string }> = []
  const chunks = await Promise.all(
    serverRows.map(async (server) => {
      try {
        const state = await fetchGreState(server)
        await captureAndAppendRevision({
          serverId: server.id,
          section: "gre",
          source: "observed",
          capture: async () => state.snapshot,
        })
        return state.tunnels
      } catch (e) {
        failures.push({
          serverId: String(server.id),
          serverName: server.name ?? undefined,
          error: e instanceof Error ? e.message : String(e),
        })
        return [] as LiveGreTunnel[]
      }
    }),
  )
  return { tunnels: chunks.flat(), failures }
}