import {css, CSSResult, unsafeCSS} from 'lit-element'

/**
 * Default Status Codes for systemVariables, define the UI appereance and behaviour of the variable.
 * They are simple strings and can be extended with custom statuses.
 */
export enum VarStatusCodes{
    /** The variable is subscribed for receiving updates. This is the default "ALL GOOD". */
    Subscribed = "SUBSCRIBED",
    
    /**Something went wrong in retrieving the variable serverside, like for example the variable does not exist or
     * is corrupted, in general an action by the admin must be taken to fix this. The user should not be able to 
     * interact with the item. The variable is not subscribed. Its value, if any, should not be trusted. 
     */
    Error = "ERROR",

    /**Loading... The variable is waiting to be written or being subscribed. Usefull to show some related UI. */
    Pending = "PENDING", 

    /**The variable value is within some "DANGER" zone. Used to show variable related alarms. */
    Warning = "WARNING",

    /**The variable is ok, but will not receive updates for some reasons, for example no network. 
     * One can trust the variable value as its last updated value.*/
    Unsubscribed = "UNSUBSCRIBED"
}

                
export var VarStatusCodesLit:{[key:string]:CSSResult}= {};
/*Object.keys(VarStatusCodes).forEach((key)=>{
    //@ts-ignore
    VarStatusCodesLit[key] = css`${unsafeCSS(VarStatusCodes[key])}`;
})*/
VarStatusCodesLit.Subscribed = css`${unsafeCSS(VarStatusCodes.Subscribed)}`
VarStatusCodesLit.Error = css`${unsafeCSS(VarStatusCodes.Error)}`
VarStatusCodesLit.Pending = css`${unsafeCSS(VarStatusCodes.Pending)}`
VarStatusCodesLit.Warning = css`${unsafeCSS(VarStatusCodes.Warning)}`
VarStatusCodesLit.Unsubscribed = css`${unsafeCSS(VarStatusCodes.Unsubscribed)}`

/**
 * Static class defining status codes for the data engine status. 
 * @prop Ready - Engine Running, all ok 
 * @prop Down  - Engine is still down, no subscription can be made, but no error was raised. 
 * @prop Warming - Waiting for initialization to complete 
 * @prop Error - Engine could not be initialized.
 * */
export class ServiceStatusCodes{
    static Ready = "READY"
    static Down = "DOWN"
    static Warming = "WARMUP"
    static Error = "ERROR"
}

/**
 * Static class defining Error codes that appear during communication with the server. 
 * These are variables related errors.
 * 
 * @prop VarNotExist - Variable was not found in server
 * @prop WontSubcribe 
 * @prop CantSubcribe
 * @prop CantUnSubcribe
 * @prop BadValue - Provided Write Request value has wrong type or could not be understood 
 * @prop NoNetwork - Network is down, cannot retrieve values
 * @prop NetError
 * @prop Unauthorized - Action cannot be performed, user has no rights. 
 * @prop BadReq - HTTP 400 error on request
 * @prop ServerError - Serverside bug? HTTP 500
 * @prop NotFound - Return from a HTTP 404 
 * @prop BadData
 * @prop EngineNotExist
 * @prop UnknownError
 */
export class ErrorCodes{
    static VarNotExist = "VAR-NOT-EXIST"
    static WontSubcribe = "WONT-SUB"
    static CantSubcribe = "CANT-SUB"
    static CantUnSubcribe = "CANT-UNSUB"
    static BadValue = "BAD-VALUE"
    static NoNetwork = "NO-NETWORK"
    static NetError = "NET-ERROR"
    static Unauthorized = "UNAUTHORIZED"
    static BadReq = "BAD-REQUEST"
    static ServerError = "SERVER-ERROR"
    static NotFound = "NOT-FOUND"
    static BadData = "BAD-DATA"
    static EngineNotExist = "NO-ENGINE"
    static UnknownError = "UKNOWN"
}

export enum Actions{
    Write = "WRITE",
    Read = "READ",
    Subscribe = "SUBSCRIBE",
    Unsubscribe = "UNSUBSCRIBE",
    Update = "UPDATE",
    Init = "INITIALIZE",
    Unknown = "UNKNOWN"
}

/** 
 * It represent a generic object belonging to a specific system.
 * 
 * @prop {string} name - Name of the variable, an identifier for the server
 * @prop {string} system - System namespace that identifies the server item
*/
export class systemObject{
    name : string 
    system : string 

    /**
     * 
     * @param Name {string} Variable Name
     * @param System {string} System Namespace
     */
    constructor(Name:string,System:string)
    {
        this.name = Name || "";
        this.system = System || "default";
    }
}

export interface basicError{
    code:string
    message?:string
}
/**
 * Describe a system error occurred during a requested Action (like subscribe, write, etc.).
 * @prop {string}  code - Error code as defined in ErrorCodes
 * @prop {string}  message  - The error message (this by default will auto build itself), but you can override it.
 * @prop {string}  systemName  - System name
 * @prop {string}  targetName  - Target of the Action that generated the error, for example the caller of a write method.
 * @prop {string}  action      - Action Code as defined in "Actions", what was going to be performed.
 * @prop {number}  timestamp_ms - Time the error occurred, by default is Date.Now()
 * @prop {boolean} ack          - If the error was acknowledged by user or not.
 */
export class systemError implements basicError{
    
    code:string
    message:string
    timestamp_ms: number
    systemName:string
    action:string
    targetName:string
    ack:boolean

    /**
     * Standard constructor, by default will auto-build the error message and will set timestamp to Now.
     * @param sysName System name for example an engine name
     * @param Code Error code as in "ErrorCodes"
     * @param target (optional) name of who is in fault, like for example a variable name. 
     * @param Action (optional) Action Code of what was going to be performed.
     */
    constructor(sysName:string, Code:string, target:string="",Action:string=""){
        // if(!(err && typeof err.code === "string")) throw TypeError("Err must be valid and of 'basicError' type: {code:string,message?:string}");
        if(typeof Code !== "string") throw TypeError("Code must be a string");
        if(typeof sysName !== "string") throw TypeError("sysName must be a string");
        //this.code = err.code;
        this.code = Code;
        this.timestamp_ms = Date.now() ;
        this.systemName = sysName;
        this.action = Action || "";
        this.targetName = target || "";
        this.ack = false;
        //this.message = err.message ? err.message : this.buildDefaultMessage();
        this.message = this.buildDefaultMessage();
    }

    buildDefaultMessage():string{
        let message = `Error in system (${this.systemName})`;
        if(this.action !== "") message += ` during ${this.action}`;
        if(this.targetName !== "") message += ` on target (${this.targetName})`;
        message +=`. Error Code: ${this.code}.`;
        return message;
    }
}

export class systemAlarm extends systemError {
    isActive : boolean

    constructor(sysName:string, Code:string, target:string, Action:string=""){
        super(sysName, Code,target, Action);
        this.isActive = true;
    }

    buildDefaultMessage():string{
        let message = `Alarm in system (${this.systemName})`;
        if(this.action !== "") message += ` during ${this.action}`;
        if(this.targetName !== "") message += ` on target (${this.targetName})`;
        message +=`. Alarm Code: ${this.code}.`;
        return message;
    }
}

/**
 * Class that implemets a general response to actions that involve variable read, write, subscribe, etc.
 * @prop {boolean} success  - weather the request had success or not
 * @prop {object}  error  - if success is false then this must not be null, contain error code and error message(optional).
 * @prop {string} name - name of the variable.
 * @prop {string}  system  -  system name related to the variable.
 * @prop {any}  value  -  the value of the variable (can be an object if supported).
 * 
 */
 export class VarResponse extends systemObject implements basicResponse {
    success:boolean
    error:basicError = null
    value:any

    /**
     * 
     * @param Success {bolean} - weather the request had success or not
     * @param name {string} - name of the variable
     * @param system {string} - system name related to the variable
     * @param value {any} -  the value of the variable (can be an object if supported)
     */
    constructor(Success:boolean, _name:string, _system:string, _value:any=null){
        super(_name,_system);
        this.success = Success;
        this.value = _value;
    }
    
    /** helper to set the "error" property. */
    setError(ErrorCode:string, Message:string=""){
        this.error = {
            code : ErrorCode,
            message : Message
        }
    }

}

/**
 * Defines a generic variable bound to a specific system.
 * The "value" must be a JSON compatible object, since these values are 
 * persisted in localstorage. So anything is good but functions.
 */
export class systemVariable extends systemObject implements variable{
    value : any 
    status: string

    constructor(sys_obj:systemObject){
        super(sys_obj.name, sys_obj.system);
        this.value = null;
        this.status = null;
    }
}

export interface basicResponse{
    success : boolean
    error?  : basicError
}

export interface variable {
    value : any 
    status: string
    [key:string] : any 
}

export interface customAction{
    (target:systemObject, data:any) : Promise<basicResponse>
}