import db from "#root/config/database.config.js";
import modbusClient from "#root/config/modbus-client.config.js";
import * as utils from '#root/utils/index.js'
import { appService, modbusService } from "#root/services/index.js";

export const modbusController = {
  /**
   * Connect to modbus network using configuration from database
   * @param {import('express').Request} req
   * @param {import('express').Response} res
   * @param {import('express').NextFunction} next
   */
  async connect(req, res, next) {
    try {
      const appConfig = await appService.getConfig();
      if (!appConfig) return res.status(400).json({ message: "Application is not configured" });
      await modbusService.connect(appConfig);
      return res.status(200).json({ message: "Connected." });
    } catch (error) {
      next(error);
    }
  },

  /**
   * Close the modbus connection
   * @param {import('express').Request} req
   * @param {import('express').Response} res
   * @param {import('express').NextFunction} next
   */
  async close(req, res, next) {
    try {
      if (!modbusClient.isOpen) return res.status(400).json({ message: "Already closed." });
      modbusClient.close(undefined);
      modbusClient.destroy(undefined);
      return res.status(200).json({ message: "Closed." });
    } catch (error) {
      next(error);
    }
  },

  /**
   * Get list of modbus slave devices
   * @param {import('express').Request} req
   * @param {import('express').Response} res
   * @param {import('express').NextFunction} next
   */
  async list(req, res, next) {
    try {
      const devices = await modbusService.getDevices();
      return res.status(200).json(devices);
    } catch (error) {
      next(error);
    }
  },

  /**
   * Create new modbus slave device
   * @param {import('express').Request} req
   * @param {import('express').Response} res
   * @param {import('express').NextFunction} next
   */
  async createDevice(req, res, next) {
    try {
      const { id, name, g_display_reg_addr, g_display_reg_format, g_display_reg_type, g_y_label } =
        req.body;
      await db.run(
        `INSERT INTO "modbus_slaves" (
                    "id", 
                    "name", 
                    "g_display_reg_addr", 
                    "g_display_reg_format",
                    "g_display_reg_type",
                    "g_y_label") 
                    VALUES (?, ?, ?, ?, ?, ?)`,
        [id, name, g_display_reg_addr, g_display_reg_format, g_display_reg_type, g_y_label],
      );
      return res.status(200).json({ message: "Device created." });
    } catch (error) {
      next(error);
    }
  },

  /**
   * Update modbus slave device
   * @param {import('express').Request} req
   * @param {import('express').Response} res
   * @param {import('express').NextFunction} next
   */
  async updateDevice(req, res, next) {
    try {
      const { 
        id,
        newId,
        name, 
        g_display_reg_addr, 
        g_display_reg_type, 
        g_display_reg_format, 
        g_y_label 
      } = req.body;

      await db.run(`UPDATE "modbus_slaves" SET 
                    id = ?, 
                    name = ?,
                    g_display_reg_addr = NULL,
                    g_display_reg_type = NULL,
                    g_display_reg_format = NULL,
                    g_y_label = NULL
                    WHERE id = ? `, 
                    [newId, name, id]);
      
      if (g_display_reg_addr !== null && 
          g_display_reg_type !== null && 
          g_display_reg_format !== null &&
          g_y_label !== null
          ) {
        await db.run(`UPDATE "modbus_slaves" SET 
                      g_display_reg_addr = ?,
                      g_display_reg_type = ?,
                      g_display_reg_format = ?,
                      g_y_label = ? WHERE id = ?`, 
                      [g_display_reg_addr, g_display_reg_type, g_display_reg_format, g_y_label, id]);
      }

      return res.status(200).json({ message: 'Updated.' })
    } catch (error) {
      next(error);
    }
  },

  /**
   * Remove modbus slave device
   * @param {import('express').Request} req
   * @param {import('express').Response} res
   * @param {import('express').NextFunction} next
   */
  async removeDevice(req, res, next) {
    try {
      const device = await db.get(`SELECT id FROM "modbus_slaves" WHERE id = ?`, [req.body.id]);
      if (!device) return res.status(404).json({ message: "Device not found." });
      await db.run(`DELETE FROM "modbus_slaves" WHERE id = ?`, [req.body.id]);
      return res.status(200).json({ message: "Device removed." });
    } catch (error) {
      next(error);
    }
  },

  /**
   * Create display value for modbus slave device
   * @param {import('express').Request} req
   * @param {import('express').Response} res
   * @param {import('express').NextFunction} next
   */
  async createDisplayValue(req, res, next) {
    try {
      const { name, slave_id, reg_addr, reg_format, reg_type } = req.body
      await db.run(`INSERT INTO "display_values" 
                    ("name", "slave_id", "reg_addr", "reg_format", "reg_type") 
                    VALUES (?, ?, ?, ?, ?)
                  `, [name, slave_id, reg_addr, reg_format, reg_type]
                  );
      return res.status(200).json({ message: 'Created.' });
    } catch (error) {
      next(error);
    }
  },

  /**
   * Remove display value from modbus slave device
   * @param {import('express').Request} req
   * @param {import('express').Response} res
   * @param {import('express').NextFunction} next
   */
  async removeDisplayValue(req, res, next) {
    try {
      await db.run(`DELETE FROM "display_values" WHERE id = ?`, req.body.id);
      return res.status(200).json({ message: "Display value removed." });
    } catch (error) {
      next(error);
    }
  },

  /**
   * Creates event stream aboud modbus connection status
   * @param {import('express').Request} req
   * @param {import('express').Response} res
   * @param {import('express').NextFunction} next
   */
  async status(req, res, next) {
    try {
      utils.setSSEHeaders(res);
      const intervalId = modbusService.startConnectionStatusInterval((status) => res.write(utils.serializeSSEData(status, 'message')))
      req.on("close", () => clearInterval(intervalId));
    } catch (error) {
      next(error);
    }
  },

  /**
   * Creates event stream for sending data from modbus device
   * @param {import('express').Request} req
   * @param {import('express').Response} res
   * @param {import('express').NextFunction} next
   */
  async streamData(req, res, next) {
    try {
      const { slave_id } = req.query;

      if (!modbusClient.isOpen) return res.status(503).json({ error: { message: "Modbus connection closed." } });
      if (!slave_id) return res.status(400).json({ error: { message: "'slave_id' parameter is required." } });

      const device = await db.get(`SELECT * FROM "modbus_slaves" WHERE id = ?`, [slave_id]);
      if (!device) return res.status(404).json({ error: { message: "Device not found." } });

      utils.setSSEHeaders(res);

      const intervalId = await modbusService.startDevicePollInterval(
        device,
        (data, error) => {
          if (error) {
            next(error);
            return;
          }
          res.write(utils.serializeSSEData(data, 'message'));
        },
      );

      req.on("close", () => clearInterval(intervalId));
    } catch (error) {
      next(error);
    }
  },
};