sourceafIoc::MappedConfig.fan

** Passed into module contribution methods to allow the method to, err, contribute!
**
** A service can *collect* contributions in three different ways:
** - As an unordered list of values
** - As an ordered list of values
** - As a map of keys and values
** 
** The service defines the *type* of contribution by declaring a parameterised list or map in its 
** ctor or builder method. Contributions must be compatible with the type.
class MappedConfig {
    
    internal const  Type            contribType
    private  const  ServiceDef      serviceDef
    private         InjectionCtx    ctx
    private         Map             config
    
    internal new make(InjectionCtx ctx, ServiceDef serviceDef, Type contribType) {
        if (contribType.name != "Map")
            throw WtfErr("Ordered Contrib Type is NOT map???")
        if (contribType.isGeneric)
            throw IocErr(IocMessages.mappedConfigTypeIsGeneric(contribType, serviceDef.serviceId)) 
        
        this.ctx            = ctx
        this.serviceDef     = serviceDef
        this.contribType    = contribType
        this.config         = (keyType == Str#) 
                            ? Map.make(contribType) { caseInsensitive = true }
                            : Map.make(contribType) { ordered = true }
    }

    ** A util method to instantiate an object, injecting any dependencies. See `Registry.autobuild`.  
    Obj autobuild(Type type) {
        ctx.objLocator.trackAutobuild(ctx, type)
    }
    
    ** Adds a keyed object to the service's configuration.
    Void addMapped(Obj key, Obj val) {
        keyType := contribType.params["K"]
        valType := contribType.params["V"]
        
        if (!key.typeof.fits(keyType))
            throw IocErr(IocMessages.mappedConfigTypeMismatch("key", key.typeof, keyType))
        if (!val.typeof.fits(valType)) {
            // special case for empty lists - as Obj[,] does not fit Str[,], we make a new Str[,] 
            if (val.typeof.name == "List" && valType.name == "List" && (val as List).isEmpty)
                val = valType.params["V"].emptyList
            else
                throw IocErr(IocMessages.mappedConfigTypeMismatch("value", val.typeof, valType))
        }
        
        config.add(key, val)
    }
    
    ** Adds all the mapped objects to a service's configuration.
    Void addMappedAll(Obj:Obj objects) {
        objects.each |val, key| {
            addMapped(key, val)
        }
    }
    
//  ** Overrides an existing contribution by its key. The key must exist.
//  Void addMappedOverride(Obj key, Obj value) {
//  }
    
    internal Void contribute(InjectionCtx ctx, Contribution contribution) {
        contribution.contributeMapped(ctx, this)
    }
    
    internal Map getConfig() {
        config
    }
    
    private once Type keyType() {
        contribType.params["K"]
    }
    
    private once Type valType() {
        contribType.params["V"]
    }
    override Str toStr() {
        "MappedConfig of $contribType"
    }   

}