import { v4 as uuidv4 } from "uuid";
import { AlexaInterface, AlexaInterfaceType } from "./AlexaInterface";
import { MqttClient } from "mqtt";

export enum EndpointHealth {
  OK = "OK",
  UNREACHABLE = "UNREACHABLE",
}

export enum ThermostatMode {
  OFF = "OFF",
  HEAT = "HEAT",
  COOL = "COOL",
  AUTO = "AUTO",
  ECO = "ECO",
  CUSTOM = "CUSTOM",
}

export enum PowerController {
  ON = "ON",
  OFF = "OFF",
}

export enum TemperatureSensorScale {
  CELSIUS = "CELSIUS",
  FAHRENHEIT = "FAHRENHEIT",
}

interface DirectiveHeader {
  namespace: string;
  name: string;
  payloadVersion: string;
  messageId: string;
  correlationToken: string;
}

interface DirectiveEndpoint {
  endpointId: string;
}

interface ContextProperty {
  namespace: string;
  name: string;
  value: any;
  timeOfSample: string;
  uncertaintyInMilliseconds: number;
  instance?: string;
}

/** Why a ChangeReport is sent (Alexa.ChangeReport payload.change.cause.type). */
export type ChangeCause = "APP_INTERACTION" | "PHYSICAL_INTERACTION" | "PERIODIC_POLL" | "RULE_TRIGGER" | "VOICE_INTERACTION";

export class AlexaStatusMessage {
  private context: { properties: ContextProperty[] } = { properties: [] };
  /** ChangeReport only: the properties that changed (payload.change.properties); the rest go to context. */
  private changeProps: ContextProperty[] = [];
  private changeCause: ChangeCause | null = null;
  private target: "context" | "change" = "context";
  private event: {
    header: DirectiveHeader;
    endpoint: DirectiveEndpoint;
    payload: {};
  };
  private rootTopic: string;
  private endpointId: string;
  private mqttClient: MqttClient;
  private isDeferred: boolean;

  constructor(
    correlationToken: string,
    rootTopic: string,
    endpointId: string,
    mqttClient: MqttClient,
    isResponse: boolean = false,
    isDeferred: boolean = false,
    changeCause: ChangeCause | null = null
  ) {
    this.rootTopic = rootTopic;
    this.endpointId = endpointId;
    this.mqttClient = mqttClient;
    this.isDeferred = isDeferred;
    this.changeCause = changeCause;
    if (changeCause) this.target = "change";
    this.event = {
      header: {
        namespace: "Alexa",
        name: changeCause
          ? "ChangeReport"
          : isDeferred
          ? "DeferredResponse"
          : isResponse
          ? "Response"
          : "StateReport",
        payloadVersion: "3",
        messageId: this.generateMessageId(),
        correlationToken,
      },
      endpoint: {
        endpointId,
      },
      payload: {},
    };
  }

  private generateMessageId(): string {
    return uuidv4();
  }

  private getTimestamp(): string {
    return new Date().toISOString();
  }
  private addProperty(
    namespace: AlexaInterfaceType,
    name: string,
    value: any,
    uncertaintyInMilliseconds = 0,
    instance?: string
  ): this {
    const prop: ContextProperty = {
      namespace,
      name,
      value,
      timeOfSample: this.getTimestamp(),
      uncertaintyInMilliseconds,
    };
    if (instance) prop.instance = instance;
    (this.target === "change" ? this.changeProps : this.context.properties).push(prop);
    return this;
  }
  /** ChangeReport: the add*Prop calls that follow describe what CHANGED (the default for a change report). */
  public changed(): this {
    this.target = "change";
    return this;
  }
  /** ChangeReport: the add*Prop calls that follow describe the other, unchanged properties (context). */
  public unchanged(): this {
    this.target = "context";
    return this;
  }
  /** True for a ChangeReport (Device.getChangeReport). */
  public isChangeReport(): boolean {
    return this.changeCause !== null;
  }
  /** The message as it will be published (for tests and logging). */
  public toJSON(): { event: any; context: { properties: ContextProperty[] } | null } {
    if (this.changeCause) {
      return {
        event: { ...this.event, payload: { change: { cause: { type: this.changeCause }, properties: this.changeProps } } },
        context: this.context,
      };
    }
    return { context: this.isDeferred ? null : this.context, event: this.event };
  }
  public addModeControllerProp(instance: string, value: string, uncertaintyInMs = 0): this {
      return this.addProperty(
        AlexaInterfaceType.MODE_CONTROLLER,
        "mode",
        value,
        uncertaintyInMs,
        instance
      );
    }     
  public addThermostatModeProp(mode: string, uncertaintyInMs = 0): this {
    return this.addProperty(
      AlexaInterfaceType.THERMOSTAT_CONTROLLER,
      "thermostatMode",
      mode,
      uncertaintyInMs
    );
  }
  public addEstimatedDeferralTime(seconds: number): this {
    if (this.isDeferred) {
      this.event.payload = {
        estimatedDeferralInSeconds: seconds,
      };
    } else {
      console.warn(
        "[AlexaStatusMessage.ts] Attempted to add estimated deferral time, but message is not marked as DeferredResponse."
      );
    }
    return this;
  }

  public addThermostatControllerProp(
    name: "lowerSetpoint" | "upperSetpoint" | "targetSetpoint",
    scale: TemperatureSensorScale,
    value: number,
    uncertaintyInMs = 0
  ): this {
    const tempValue = {
      value:
        scale === TemperatureSensorScale.FAHRENHEIT
          ? (value - 32) * (5 / 9)
          : value,
      scale: "CELSIUS",
    };
    return this.addProperty(
      AlexaInterfaceType.THERMOSTAT_CONTROLLER,
      name,
      tempValue,
      uncertaintyInMs
    );
  }

  public addHealthProp(health: EndpointHealth, uncertaintyInMs = 0): this {
    return this.addProperty(
      AlexaInterfaceType.ENDPOINT_HEALTH,
      "connectivity",
      { value: health },
      uncertaintyInMs
    );
  }

  public addPowerControllerProp(
    power: PowerController,
    uncertaintyInMs = 0
  ): this {
    return this.addProperty(
      AlexaInterfaceType.POWER_CONTROLLER,
      "powerState",
      power,
      uncertaintyInMs
    );
  }

  public addTemperatureSensorProp(
    scale: TemperatureSensorScale,
    value: number,
    uncertaintyInMs = 0
  ): this {
    const tempValue = {
      value:
        scale === TemperatureSensorScale.FAHRENHEIT
          ? (value - 32) * (5 / 9)
          : value,
      scale: "CELSIUS",
    };
    return this.addProperty(
      AlexaInterfaceType.TEMPERATURE_SENSOR,
      "temperature",
      tempValue,
      uncertaintyInMs
    );
  }

  public addBrightnessControllerProp(
    brightness: number,
    uncertaintyInMs = 0
  ): this {
    return this.addProperty(
      AlexaInterfaceType.BRIGHTNESS_CONTROLLER,
      "brightness",
      brightness,
      uncertaintyInMs
    );
  }

  public addColorTemperatureControllerProp(
    colorTemp: number,
    uncertaintyInMs = 0
  ): this {
    return this.addProperty(
      AlexaInterfaceType.COLOR_TEMPERATURE_CONTROLLER,
      "colorTemperatureInKelvin",
      colorTemp,
      uncertaintyInMs
    );
  }

  public addToggleControllerProp(
    state: PowerController,
    instance: string,
    uncertaintyInMs = 0
  ): this {
    return this.addProperty(
      AlexaInterfaceType.TOGGLE_CONTROLLER,
      "toggleState",
      state,
      uncertaintyInMs,
      instance
    );
  }

  public addContextProp(prop: ContextProperty): this {
    this.context.properties.push(prop);
    return this;
  }

  /**
   * Publish: a Response/StateReport to <root>/<endpoint>/alexaResponce (sendAsync: deferredResponse), a ChangeReport
   * to <root>/changeReport (Alex2MQTT adds the user's token and posts it to the Alexa event gateway). Resolves with
   * the topic; rejects on a publish error (1.4.0 only logged).
   */
  public send(sendAsync: boolean = false): Promise<string> {
    const payloadStr = JSON.stringify(this.toJSON());
    const topic = this.changeCause
      ? `${this.rootTopic}/changeReport`
      : `${this.rootTopic}/${this.endpointId}/${sendAsync ? "deferredResponse" : "alexaResponce"}`; //Yes this should be response but it is incorrect in both Alex2MQTT and Alex2ESP so for consistency is is wrong here too
    return new Promise((resolve, reject) => {
      this.mqttClient.publish(topic, payloadStr, (err) => (err ? reject(err) : resolve(topic)));
    });
  }
}