import { requireAuth, requireCap } from '../auth.js'
import { pool } from '../db.js'
import { parseIntesisMapsExport } from '../lib/mhi-xlsx-import.js'
import * as mhiDriver from '../lib/drivers/mhi-modbus.js'

// MHI Modbus TCP gateway configuration + register-map import. Manual control
// only for now (see lib/drivers/mhi-modbus.js) — this never touches
// lib/scheduler.js. Importing a MAPS export only STAGES the parsed result on
// the gateway row for staff review; no zone_devices rows are created until an
// explicit "Assign to Zone" per unit (see the /units/:unitIndex/assign route).
export async function mhiGatewayRoutes(app) {
  app.addHook('preHandler', requireAuth)

  // GET /api/mhi-gateways — configured gateways + how many units are assigned from each
  app.get('/api/mhi-gateways', { preHandler: requireCap('view') }, async () => {
    const { rows } = await pool.query(`
      SELECT g.*,
        (SELECT COUNT(*)::int FROM zone_devices zd WHERE zd.mhi_gateway_id = g.id) AS assigned_count
      FROM mhi_gateways g
      ORDER BY g.name
    `)
    return rows
  })

  // POST /api/mhi-gateways — { name, host, port, slaveId, addressBase }
  app.post('/api/mhi-gateways', { preHandler: requireCap('manage_devices') }, async (req, reply) => {
    const { name, host, port, slaveId, addressBase } = req.body || {}
    if (!name || !host) return reply.status(400).send({ error: 'name and host are required' })

    const { rows } = await pool.query(
      `INSERT INTO mhi_gateways (name, host, port, slave_id, address_base)
       VALUES ($1, $2, $3, $4, $5) RETURNING *`,
      [name, host, port || 502, slaveId || 1, addressBase ?? 0]
    )
    return rows[0]
  })

  // PATCH /api/mhi-gateways/:id — edit connection details
  app.patch('/api/mhi-gateways/:id', { preHandler: requireCap('manage_devices') }, async (req, reply) => {
    const { rows: existing } = await pool.query('SELECT * FROM mhi_gateways WHERE id = $1', [req.params.id])
    if (!existing.length) return reply.status(404).send({ error: 'Gateway not found' })
    const g = existing[0]
    const { name, host, port, slaveId, addressBase } = req.body || {}

    const { rows } = await pool.query(
      `UPDATE mhi_gateways SET
         name = $1, host = $2, port = $3, slave_id = $4, address_base = $5, updated_at = NOW()
       WHERE id = $6 RETURNING *`,
      [
        name ?? g.name, host ?? g.host, port ?? g.port,
        slaveId ?? g.slave_id, addressBase ?? g.address_base, req.params.id,
      ]
    )
    return rows[0]
  })

  // DELETE /api/mhi-gateways/:id — remove a gateway config entirely. Main use:
  // retiring a gateway after it's switched to native MQTT (see lib/mqtt.js) and
  // its Modbus register-map config is no longer needed. Devices that reference
  // this gateway (device_type='mhi_modbus') are NOT deleted — mhi_gateway_id
  // just goes NULL (ON DELETE SET NULL) — delete those rows separately via
  // DELETE /api/devices/:id if they're being retired too.
  app.delete('/api/mhi-gateways/:id', { preHandler: requireCap('manage_devices') }, async (req, reply) => {
    const { rows } = await pool.query('SELECT id FROM mhi_gateways WHERE id = $1', [req.params.id])
    if (!rows.length) return reply.status(404).send({ error: 'Gateway not found' })
    await pool.query('DELETE FROM mhi_gateways WHERE id = $1', [req.params.id])
    return { ok: true }
  })

  // POST /api/mhi-gateways/:id/test-connection — live Modbus read of the
  // gateway comm status register (same check as scripts/test-modbus-connection.py)
  app.post('/api/mhi-gateways/:id/test-connection', { preHandler: requireCap('manage_devices') }, async (req, reply) => {
    const { rows } = await pool.query('SELECT * FROM mhi_gateways WHERE id = $1', [req.params.id])
    if (!rows.length) return reply.status(404).send({ error: 'Gateway not found' })
    const result = await mhiDriver.discover(rows[0])
    return result
  })

  // POST /api/mhi-gateways/:id/import — multipart .xlsx upload (same
  // @fastify/multipart pattern as devices.js's photo upload route). Parses and
  // STAGES the result on the gateway row — nothing else is written.
  app.post('/api/mhi-gateways/:id/import', { preHandler: requireCap('manage_devices') }, async (req, reply) => {
    const { rows: existing } = await pool.query('SELECT id FROM mhi_gateways WHERE id = $1', [req.params.id])
    if (!existing.length) return reply.status(404).send({ error: 'Gateway not found' })

    let fileBuffer = null, fileName = null
    for await (const part of req.parts()) {
      if (part.type === 'file') {
        const chunks = []
        for await (const chunk of part.file) chunks.push(chunk)
        fileBuffer = Buffer.concat(chunks)
        fileName = part.filename
      }
    }
    if (!fileBuffer) return reply.status(400).send({ error: 'No file uploaded' })

    let parsed
    try {
      parsed = parseIntesisMapsExport(fileBuffer)
    } catch (err) {
      return reply.status(400).send({ error: err.message })
    }

    const { rows } = await pool.query(
      `UPDATE mhi_gateways SET imported_filename = $1, imported_units = $2, imported_at = NOW(), updated_at = NOW()
       WHERE id = $3 RETURNING *`,
      [fileName, JSON.stringify(parsed), req.params.id]
    )
    return rows[0]
  })

  // POST /api/mhi-gateways/:id/units/:unitIndex/assign — { zone_id, location }
  // creates/updates a zone_devices row (device_type='mhi_modbus') from the
  // gateway's last staged import. Pulls that unit's `fields` register map
  // straight from imported_units — this is the one-time "commit" step for a
  // unit; re-running an import + re-assigning refreshes the stored map.
  app.post('/api/mhi-gateways/:id/units/:unitIndex/assign', { preHandler: requireCap('manage_devices') }, async (req, reply) => {
    const { rows: gwRows } = await pool.query('SELECT * FROM mhi_gateways WHERE id = $1', [req.params.id])
    if (!gwRows.length) return reply.status(404).send({ error: 'Gateway not found' })
    const gateway = gwRows[0]

    const unitIndex = parseInt(req.params.unitIndex, 10)
    if (!Number.isFinite(unitIndex)) return reply.status(400).send({ error: 'Invalid unit index' })

    const unit = (gateway.imported_units?.units || []).find(u => u.unitIndex === unitIndex)
    if (!unit) {
      return reply.status(404).send({
        error: `Unit ${unitIndex} not found in this gateway's last import — import (or re-import) the MAPS export first.`,
      })
    }

    const { zone_id, location } = req.body || {}
    const externalRef = `mhi:${gateway.id}:${unitIndex}`

    const { rows } = await pool.query(
      `INSERT INTO zone_devices
         (device_type, external_ref, discovered_name, zone_id, location,
          mhi_gateway_id, mhi_unit_index, mhi_iu_address, mhi_register_map)
       VALUES ('mhi_modbus', $1, $2, $3, $4, $5, $6, $7, $8)
       ON CONFLICT (device_type, external_ref) DO UPDATE SET
         zone_id           = EXCLUDED.zone_id,
         location          = EXCLUDED.location,
         mhi_gateway_id    = EXCLUDED.mhi_gateway_id,
         mhi_unit_index    = EXCLUDED.mhi_unit_index,
         mhi_iu_address    = EXCLUDED.mhi_iu_address,
         mhi_register_map  = EXCLUDED.mhi_register_map,
         updated_at        = NOW()
       RETURNING *`,
      [
        externalRef,
        `MHI Unit ${unitIndex}`,
        zone_id || null,
        location || null,
        gateway.id,
        unitIndex,
        unit.iu ?? null,
        JSON.stringify(unit.fields),
      ]
    )
    return rows[0]
  })
}