import * as fs from 'fs-extra';
import * as path from 'path';
import { Router } from 'express';
import { connect } from 'mqtt';
import {
  SignalKApp,
  SignalKPlugin,
  MQTTExportConfig,
  ExportRule,
  SignalKDelta,
  SignalKUpdate,
  SignalKValue,
  SignalKContext,
  SignalKPath,
  SignalKTimestamp,
  PluginState,
  TypedRequest,
  TypedResponse,
  RulesApiResponse,
  MQTTStatusApiResponse,
  ApiResponse,
  RuleUpdateRequest,
  MQTTClientOptions,
  ValueChangeResult,
} from './types';

export = function (app: SignalKApp): SignalKPlugin {
  const plugin: SignalKPlugin = {
    id: 'signalk-mqtt-export',
    name: 'SignalK MQTT Export Manager',
    description:
      'Selectively export SignalK data to MQTT with webapp management interface',
    schema: {},
    start: () => {},
    stop: () => {},
    registerWithRouter: undefined,
  };

  // Plugin state
  const state: PluginState = {
    mqttClient: null,
    exportRules: [],
    activeSubscriptions: new Map<string, ExportRule[]>(),
    lastSentValues: new Map<string, unknown>(),
    currentConfig: undefined,
    unsubscribes: [],
  };

  plugin.start = function (options: Partial<MQTTExportConfig>): void {
    app.debug('Starting SignalK MQTT Export Manager plugin');

    const config: MQTTExportConfig = {
      mqttBroker: options?.mqttBroker || 'mqtt://localhost:1883',
      mqttClientId: options?.mqttClientId || 'signalk-mqtt-export',
      mqttUsername: options?.mqttUsername || '',
      mqttPassword: options?.mqttPassword || '',
      topicPrefix: options?.topicPrefix || '',
      enabled: options?.enabled !== false,
      exportRules: options?.exportRules || getDefaultExportRules(),
    };

    state.currentConfig = config;
    plugin.config = config;
    state.exportRules = config.exportRules;

    if (!config.enabled) {
      app.debug('MQTT Export plugin disabled');
      return;
    }

    // Initialize MQTT client
    initializeMQTTClient(config);

    // Set up SignalK subscriptions based on export rules
    updateSubscriptions();

    app.debug('SignalK MQTT Export Manager plugin started');
  };

  plugin.stop = function (): void {
    app.debug('Stopping SignalK MQTT Export Manager plugin');

    // Disconnect MQTT client
    if (state.mqttClient) {
      state.mqttClient.end();
      state.mqttClient = null;
    }

    // Unsubscribe from all SignalK subscriptions
    state.unsubscribes.forEach(unsubscribe => {
      if (typeof unsubscribe === 'function') {
        unsubscribe();
      }
    });
    state.unsubscribes = [];

    state.activeSubscriptions.clear();
    state.lastSentValues.clear();
    app.debug('SignalK MQTT Export Manager plugin stopped');
  };

  // Initialize MQTT client
  function initializeMQTTClient(config: MQTTExportConfig): void {
    try {
      const mqttOptions: MQTTClientOptions = {
        clientId: config.mqttClientId,
        clean: true,
        reconnectPeriod: 5000,
        keepalive: 60,
      };

      if (config.mqttUsername && config.mqttPassword) {
        mqttOptions.username = config.mqttUsername;
        mqttOptions.password = config.mqttPassword;
      }

      state.mqttClient = connect(config.mqttBroker, mqttOptions);

      state.mqttClient.on('connect', () => {
        app.debug(`✅ Connected to MQTT broker: ${config.mqttBroker}`);
      });

      state.mqttClient.on('error', (error: Error) => {
        app.debug(`❌ MQTT client error: ${error.message}`);
      });

      state.mqttClient.on('close', () => {
        app.debug('🔌 MQTT client disconnected');
      });

      state.mqttClient.on('reconnect', () => {
        app.debug('🔄 MQTT client reconnecting...');
      });
    } catch (error) {
      app.debug(
        `Failed to initialize MQTT client: ${(error as Error).message}`
      );
    }
  }

  // Update SignalK subscriptions based on export rules
  function updateSubscriptions(): void {
    // Clear existing subscriptions
    state.unsubscribes.forEach(unsubscribe => {
      if (typeof unsubscribe === 'function') {
        unsubscribe();
      }
    });
    state.unsubscribes = [];
    state.activeSubscriptions.clear();

    // Group export rules by context for efficient subscriptions
    const contextGroups = new Map<string, ExportRule[]>();
    state.exportRules
      .filter(rule => rule.enabled)
      .forEach(rule => {
        const context = rule.context || 'vessels.self';
        if (!contextGroups.has(context)) {
          contextGroups.set(context, []);
        }
        contextGroups.get(context)!.push(rule);
      });

    // Create subscriptions for each context group
    contextGroups.forEach((rules, context) => {
      const subscription = {
        context: context as SignalKContext,
        subscribe: rules.map(rule => ({
          path: rule.path as SignalKPath,
          policy: 'fixed' as const,
          period: rule.period || 1000,
          format: 'delta' as const,
        })),
      };

      app.debug(
        `Creating subscription for context ${context} with ${rules.length} paths`
      );

      app.subscriptionmanager.subscribe(
        subscription as never,
        state.unsubscribes,
        (subscriptionError: unknown) => {
          app.debug(`Subscription error for ${context}: ${subscriptionError}`);
        },
        delta => {
          handleSignalKData(delta, rules);
        }
      );

      state.activeSubscriptions.set(context, rules);
    });

    app.debug(
      `Active subscriptions: ${state.activeSubscriptions.size} contexts, ${state.exportRules.filter(r => r.enabled).length} total rules`
    );
  }

  // Handle incoming SignalK data
  function handleSignalKData(
    delta: SignalKDelta,
    contextRules: ExportRule[]
  ): void {
    if (!delta.updates || !state.mqttClient || !state.mqttClient.connected) {
      return;
    }

    delta.updates.forEach(update => {
      const typedUpdate = update as {
        values?: SignalKValue[];
        $source?: string;
        source?: { label?: string };
      };
      if (!typedUpdate.values || !Array.isArray(typedUpdate.values)) return;

      typedUpdate.values.forEach((valueUpdate: SignalKValue) => {
        // Find matching export rule
        const rule = contextRules.find(r => {
          if (!r.enabled) return false;

          // Check path match (support wildcards)
          let pathMatch = false;
          if (r.path === '*') {
            pathMatch = true;
          } else if (r.path === valueUpdate.path) {
            pathMatch = true;
          } else if (r.path.endsWith('*')) {
            // Handle wildcard patterns like "navigation*"
            const prefix = r.path.slice(0, -1);
            pathMatch = valueUpdate.path.startsWith(prefix);
          }

          if (!pathMatch) {
            return false;
          }

          // Check source match
          const sourceMatch =
            !r.source ||
            !r.source.trim() ||
            r.source === (typedUpdate.$source || typedUpdate.source?.label);
          if (!sourceMatch) return false;

          // Check MMSI exclusion list
          if (r.excludeMMSI && r.excludeMMSI.trim() && delta.context) {
            const excludedMMSIs = r.excludeMMSI
              .split(',')
              .map(mmsi => mmsi.trim());
            const contextHasExcludedMMSI = excludedMMSIs.some(mmsi =>
              delta.context?.includes(mmsi)
            );
            if (contextHasExcludedMMSI) {
              return false;
            }
          }

          return true;
        });

        if (rule) {
          publishToMQTT(delta, typedUpdate, valueUpdate, rule);
        }
      });
    });
  }

  // Publish data to MQTT
  function publishToMQTT(
    delta: SignalKDelta,
    update: {
      values?: SignalKValue[];
      $source?: string;
      source?: { label?: string };
    },
    valueUpdate: SignalKValue,
    rule: ExportRule
  ): void {
    try {
      const context = delta.context || 'vessels.self';
      const path = valueUpdate.path;
      const value = valueUpdate.value;

      // Check if we should only send on change
      if (rule.sendOnChange) {
        const changeResult = checkValueChange(context, path, value);
        if (!changeResult.hasChanged) {
          return; // Value hasn't changed, don't send
        }
      }

      // Build MQTT topic
      let topic = '';
      if (state.currentConfig?.topicPrefix) {
        topic = `${state.currentConfig.topicPrefix}/`;
      }

      if (rule.topicTemplate) {
        // Use custom topic template
        topic += rule.topicTemplate
          .replace('{context}', context)
          .replace('{path}', path)
          .replace(/\./g, '/');
      } else {
        // Default topic structure: context/path
        topic += `${context}/${path}`.replace(/\./g, '/');
      }

      // Build payload
      let payload: string;
      if (rule.payloadFormat === 'value-only') {
        payload =
          typeof value === 'object' ? JSON.stringify(value) : String(value);
      } else {
        // Full format: check if custom source label is provided
        if (rule.sourceLabel && rule.sourceLabel.trim()) {
          // Construct a new SignalK delta with custom source label
          const customDelta: SignalKDelta = {
            context: context as SignalKContext,
            updates: [
              {
                $source: rule.sourceLabel,
                timestamp: new Date().toISOString() as SignalKTimestamp,
                values: [
                  {
                    path: path as SignalKPath,
                    value: value,
                  },
                ],
              } as SignalKUpdate,
            ],
          };
          payload = JSON.stringify(customDelta);
        } else {
          // Use original SignalK delta structure (preserves original source)
          payload = JSON.stringify(delta);
        }
      }

      // Publish to MQTT
      state.mqttClient!.publish(
        topic,
        payload,
        { qos: (rule.qos || 0) as 0 | 1 | 2, retain: rule.retain || false },
        err => {
          if (err) {
            app.debug(`MQTT publish error: ${err.message}`);
          } else {
            app.debug(
              `✅ Published to MQTT: ${topic} = ${payload.substring(0, 100)}${payload.length > 100 ? '...' : ''}`
            );
          }
        }
      );
    } catch (error) {
      app.debug(`Error publishing to MQTT: ${(error as Error).message}`);
    }
  }

  // Check if value has changed
  function checkValueChange(
    context: string,
    path: string,
    value: unknown
  ): ValueChangeResult {
    const valueKey = `${context}:${path}`;
    const lastValue = state.lastSentValues.get(valueKey);

    // Compare values (handle objects and primitives)
    const currentValueString =
      typeof value === 'object' ? JSON.stringify(value) : String(value);

    // If we have a previous value, compare it
    if (lastValue !== undefined) {
      const lastValueString =
        typeof lastValue === 'object'
          ? JSON.stringify(lastValue)
          : String(lastValue);

      if (currentValueString === lastValueString) {
        // Value hasn't changed
        return {
          hasChanged: false,
          currentValue: value,
          previousValue: lastValue,
        };
      }
    }

    // Store new value for next comparison (either first time or value changed)
    state.lastSentValues.set(valueKey, value);

    return {
      hasChanged: true,
      currentValue: value,
      previousValue: lastValue,
    };
  }

  // Get default export rules (based on actual SignalK data sources)
  function getDefaultExportRules(): ExportRule[] {
    return [
      {
        id: 'all-navigation',
        name: 'All Navigation Data',
        context: 'vessels.self',
        path: 'navigation*',
        source: '', // All sources
        enabled: true,
        period: 1000,
        qos: 0,
        retain: false,
        payloadFormat: 'full',
        sendOnChange: true,
      },
      {
        id: 'derived-data',
        name: 'Derived Data',
        context: 'vessels.self',
        path: '*',
        source: 'derived-data',
        enabled: true,
        period: 1000,
        qos: 0,
        retain: false,
        payloadFormat: 'full',
        sendOnChange: true,
      },
      {
        id: 'pypilot',
        name: 'PyPilot Data',
        context: 'vessels.self',
        path: '*',
        source: 'pypilot',
        enabled: true,
        period: 1000,
        qos: 0,
        retain: false,
        payloadFormat: 'full',
        sendOnChange: true,
      },
      {
        id: 'anchoralarm',
        name: 'Anchor Alarm',
        context: 'vessels.self',
        path: '*',
        source: 'anchoralarm',
        enabled: true,
        period: 1000,
        qos: 0,
        retain: false,
        payloadFormat: 'full',
        sendOnChange: true,
      },
      {
        id: 'all-vessels',
        name: 'All Vessels (AIS)',
        context: 'vessels.*',
        path: '*',
        source: '', // All sources
        excludeMMSI: '368396230', // Exclude own vessel
        enabled: true,
        period: 1000,
        qos: 0,
        retain: false,
        payloadFormat: 'full',
        sendOnChange: true,
      },
      {
        id: 'ais-vessels',
        name: 'AIS Vessels',
        context: 'vessels.urn:*',
        path: '*',
        source: '', // All sources
        excludeMMSI: '368396230', // Exclude own vessel
        enabled: true,
        period: 1000,
        qos: 0,
        retain: false,
        payloadFormat: 'full',
        sendOnChange: true,
      },
    ];
  }

  // Plugin webapp routes
  plugin.registerWithRouter = function (router: Router): void {
    const express = require('express');

    app.debug('registerWithRouter called for MQTT export manager');

    // API Routes

    // Get current export rules
    router.get(
      '/api/rules',
      (_: TypedRequest, res: TypedResponse<RulesApiResponse>) => {
        res.json({
          success: true,
          rules: state.exportRules,
          activeSubscriptions: state.activeSubscriptions.size,
          mqttConnected: state.mqttClient ? state.mqttClient.connected : false,
        });
      }
    );

    // Update export rules
    router.post(
      '/api/rules',
      (
        req: TypedRequest<RuleUpdateRequest>,
        res: TypedResponse<ApiResponse>
      ) => {
        try {
          const newRules = req.body.rules;
          if (!Array.isArray(newRules)) {
            return res
              .status(400)
              .json({ success: false, error: 'Rules must be an array' });
          }

          state.exportRules = newRules;
          if (plugin.config) {
            plugin.config.exportRules = newRules;
          }

          // Save configuration to persistent storage
          app.savePluginOptions(plugin.config || {}, (err: Error | null) => {
            if (err) {
              app.debug(`Error saving plugin configuration: ${err.message}`);
              return res.status(500).json({
                success: false,
                error: 'Failed to save configuration',
              });
            }

            // Update subscriptions with new rules
            updateSubscriptions();

            res.json({
              success: true,
              message: 'Export rules updated and saved',
            });
          });
        } catch (error) {
          res
            .status(500)
            .json({ success: false, error: (error as Error).message });
        }
      }
    );

    // Get MQTT connection status
    router.get(
      '/api/mqtt-status',
      (_: TypedRequest, res: TypedResponse<MQTTStatusApiResponse>) => {
        res.json({
          success: true,
          connected: state.mqttClient ? state.mqttClient.connected : false,
          broker: state.currentConfig?.mqttBroker,
          clientId: state.currentConfig?.mqttClientId,
        });
      }
    );

    // Test MQTT connection
    router.post(
      '/api/test-mqtt',
      (_: TypedRequest, res: TypedResponse<ApiResponse>) => {
        try {
          if (!state.mqttClient || !state.mqttClient.connected) {
            return res
              .status(503)
              .json({ success: false, error: 'MQTT not connected' });
          }

          const testTopic = `${state.currentConfig?.topicPrefix || 'test'}/signalk-mqtt-export-test`;
          const testPayload = JSON.stringify({
            test: true,
            timestamp: new Date().toISOString(),
            message: 'Test message from SignalK MQTT Export Manager',
          });

          state.mqttClient.publish(testTopic, testPayload, { qos: 0 });
          res.json({
            success: true,
            message: 'Test message published',
            topic: testTopic,
          });
        } catch (error) {
          res
            .status(500)
            .json({ success: false, error: (error as Error).message });
        }
      }
    );

    // Serve static files
    const publicPath = path.join(__dirname, '../public');
    if (fs.existsSync(publicPath)) {
      router.use(express.static(publicPath));
      app.debug(`Static files served from: ${publicPath}`);
    }

    app.debug('MQTT Export Manager web routes registered');
  };

  // Configuration schema
  plugin.schema = {
    type: 'object',
    properties: {
      enabled: {
        type: 'boolean',
        title: 'Enable MQTT Export',
        description: 'Enable/disable the MQTT export functionality',
        default: true,
      },
      mqttBroker: {
        type: 'string',
        title: 'MQTT Broker URL',
        description:
          'MQTT broker connection string (e.g., mqtt://localhost:1883)',
        default: 'mqtt://localhost:1883',
      },
      mqttClientId: {
        type: 'string',
        title: 'MQTT Client ID',
        description: 'Unique client identifier for MQTT connection',
        default: 'signalk-mqtt-export',
      },
      mqttUsername: {
        type: 'string',
        title: 'MQTT Username',
        description: 'Username for MQTT authentication (optional)',
        default: '',
      },
      mqttPassword: {
        type: 'string',
        title: 'MQTT Password',
        description: 'Password for MQTT authentication (optional)',
        default: '',
      },
      topicPrefix: {
        type: 'string',
        title: 'Topic Prefix',
        description: 'Optional prefix for all MQTT topics',
        default: '',
      },
    },
  };

  return plugin;
};