import { readFileSync } from 'node:fs'
import { createHash } from 'node:crypto'
import { join } from 'node:path'
import type { FastifyPluginAsync } from 'fastify'
import { repos } from '@evofw/db'
import { applyReportBodySchema, POLICY_BUDGET, POLICY_BUDGET_ERROR, agentPolicyQuerySchema, policyBudgetErrorEnvelopeSchema } from '@evofw/shared'
import type { AppConfig } from '../config.js'
import { evaluateAgentPolicy, policyBudgetExceeded } from '../services/policy/evaluate.js'
import { renderMikrotikPolicyRsc } from '../services/policy/mikrotik-rsc.js'
import { ingestTelemetry } from '../services/telemetry.js'
import { AppError } from '../plugins/error-handler.js'
import { resolveAgentScriptsDir } from '../services/agent-scripts-path.js'
import { resolveAndRenderInstall } from '../services/install-links.js'
import {
  getSyncScriptMeta,
  ifNoneMatchHits,
} from '../services/sync-script.js'

const scriptsDir = resolveAgentScriptsDir()




export const agentRoutes: FastifyPluginAsync<{ config: AppConfig }> = async (
  app,
  opts,
) => {
  const { config } = opts

  app.get('/v1/agent/install.sh', async (_req, reply) => {
    const body = readFileSync(join(scriptsDir, 'install.sh'), 'utf-8')
    return reply.type('text/x-shellscript').send(body)
  })

  app.get<{ Params: { id: string } }>(
    '/agent-install/:id',
    async (req, reply) => {
      const link = repos.getInstallLink(app.db, req.params.id)
      if (!link) throw new AppError('NOT_FOUND', 'Install link not found', 404)
      const { body, contentType } = resolveAndRenderInstall(
        app.db,
        link,
        config.publicBaseUrl,
        config.enrollSeed,
      )
      return reply.header('cache-control', 'no-store').type(contentType).send(body)
    },
  )

  app.get('/v1/agent/sync-script', async (req, reply) => {
    const meta = getSyncScriptMeta()
    reply.header('ETag', meta.etag)
    reply.header('X-Evofw-Script-Sha256', meta.sha256)
    const inm = req.headers['if-none-match']
    if (ifNoneMatchHits(inm, meta.etag)) {
      return reply.code(304).send()
    }
    return reply.type('text/x-shellscript').send(meta.body)
  })

  app.get('/v1/agent/uninstall.sh', async (_req, reply) => {
    const body = readFileSync(join(scriptsDir, 'uninstall.sh'), 'utf-8')
    return reply.type('text/x-shellscript').send(body)
  })

  app.get('/v1/agent/mikrotik-install.rsc', async (_req, reply) => {
    const body = readFileSync(
      join(scriptsDir, 'mikrotik-install.rsc'),
      'utf-8',
    )
    return reply.type('text/plain').send(body)
  })


  app.get('/v1/agent/policy', async (req, reply) => {
    const query = agentPolicyQuerySchema.parse(req.query)
    try {
      const agentId = req.agentId!
      // Record contact first — empty policy (no rule sets) is a valid online state.
      repos.updateAgent(app.db, agentId, {
        lastSeenAt: new Date().toISOString(),
        lastSeenIp: req.ip,
      })
      const policy = evaluateAgentPolicy(app.db, agentId)
      const scriptSha = getSyncScriptMeta().sha256
      const response = {
        generation: policy.generation,
        hash: policy.hash,
        apply_version: policy.applyVersion,
        default_action: policy.defaultAction,
        policy_mode: policy.policyMode,
        script_sha256: scriptSha,
        deny_cidrs: policy.denyCidrs,
        allow_cidrs: policy.allowCidrs,
        port_rules: policy.portRules.map((r) => ({
          id: r.id,
          action: r.action,
          protocol: r.protocol,
          port_start: r.portStart,
          port_end: r.portEnd,
          src_cidrs: r.srcCidrs,
        })),
        sync_interval_sec: policy.syncIntervalSec,
        // compat: prefixes = deny when default accept, else allow (legacy single-bag clients)
        prefixes:
          policy.defaultAction === 'accept'
            ? policy.denyCidrs
            : policy.allowCidrs,
        total:
          policy.defaultAction === 'accept'
            ? policy.denyCidrs.length
            : policy.allowCidrs.length,
      }
      const json = JSON.stringify(response)
      if (Buffer.byteLength(json) > POLICY_BUDGET.jsonBytes) policyBudgetExceeded('8MiB policy response JSON')
      const etag = `"policy-v1-${createHash('sha256').update(json).digest('hex')}"`
      repos.updateAgent(app.db, agentId, { desiredHash: policy.hash, desiredHashGeneration: policy.generation, lastPolicyDeliveredAt: new Date().toISOString() })
      reply.header('etag', etag).header('cache-control', 'private, no-cache')
      if (ifNoneMatchHits(req.headers['if-none-match'], etag)) return reply.code(304).send()
      return reply.type('application/json').send(json)
    } catch (error) {
      if (query.transport === 'routeros' && error instanceof AppError && error.code === POLICY_BUDGET_ERROR) {
        reply.removeHeader('etag')
        return reply.header('cache-control', 'no-store').code(200).send(policyBudgetErrorEnvelopeSchema.parse({ error: { code: POLICY_BUDGET_ERROR, message: error.message.slice(0, 512) } }))
      }
      throw error
    }
  })

  app.get('/v1/agent/policy.rsc', async (req, reply) => {
    const agentId = req.agentId!
    repos.updateAgent(app.db, agentId, {
      lastSeenAt: new Date().toISOString(),
      lastSeenIp: req.ip,
    })
    const policy = evaluateAgentPolicy(app.db, agentId)
    const script = renderMikrotikPolicyRsc(policy)
    if (Buffer.byteLength(script) > POLICY_BUDGET.jsonBytes) policyBudgetExceeded('8MiB RouterOS policy response')
    repos.updateAgent(app.db, agentId, { desiredHash: policy.hash, desiredHashGeneration: policy.generation, lastPolicyDeliveredAt: new Date().toISOString() })
    const etag = `"policy-rsc-v1-${createHash('sha256').update(script).digest('hex')}"`
    reply.header('etag', etag).header('cache-control', 'private, no-cache')
    if (ifNoneMatchHits(req.headers['if-none-match'], etag)) return reply.code(304).send()
    return reply.type('text/plain').send(script)
  })

  app.post('/v1/agent/apply-report', async (req) => {
    const body = applyReportBodySchema.parse(req.body)
    const result = ingestTelemetry(app.db, req.agentId!, body, req.ip)
    return { ...result, ...(body.telemetry_version === 2 ? { report_id: body.report_id, sequence: body.sequence, sequence_floor: repos.getTelemetryState(app.db, req.agentId!)!.sequence } : {}) }
  })

  app.post('/v1/agent/heartbeat', async (req) => {
    const agentId = req.agentId!
    repos.updateAgent(app.db, agentId, {
      lastSeenAt: new Date().toISOString(),
      lastSeenIp: req.ip,
    })
    return { ok: true }
  })
}