/*
cc -o /tmp/iodt graphics.subproj/IODisplayTest.c -framework CoreGraphics -Wall -undefined warning -g
*/

#include <CoreFoundation/CoreFoundation.h>
#include <CoreGraphics/CoreGraphicsPrivate.h>
#include <IOKit/graphics/IOGraphicsLib.h>
#include <stdlib.h>

#include "IODisplayInterface.h"

void KeyArrayCallback(const void *key, const void *value, void *context)
{
    CFArrayAppendValue(context, key);
}

int main(int argc, char * argv[])
{
    io_service_t 	service;
    CFDictionaryRef	dict;
    CFDictionaryRef	names;
    CFArrayRef		langKeys;
    CFArrayRef		orderLangKeys;
    CFNumberRef		num;
    CGSError		err;
    SInt32		numValue;
    int			i;
    CGSDisplayNumber	max;
    CGSDisplayID	displayIDs[8];
    CGSInitialize();

    err = CGSGetDisplayList(8, displayIDs, &max);
    if(err != kCGSErrorSuccess)
        exit(1);
    if(max > 8)
        max = 8;

    for(i = 0; i < max; i++ ) {
        err = CGSServiceForDisplayNumber(displayIDs[i], &service);
        if(err != kCGSErrorSuccess)
            continue;
    
        dict = IODisplayCreateInfoDictionary(service, kNilOptions );
        if( dict) {
            printf("Display %d\n", i);

            num = CFDictionaryGetValue(dict, CFSTR(kDisplayVendorID));
            if(num) {
                CFNumberGetValue(num, kCFNumberSInt32Type, &numValue);
                printf("vendorID %ld\n", numValue);
            }
            num = CFDictionaryGetValue(dict, CFSTR(kDisplayProductID));
            if(num) {
                CFNumberGetValue(num, kCFNumberSInt32Type, &numValue);
                printf("productID %ld\n", numValue);
            }

            names = CFDictionaryGetValue(dict, CFSTR(kDisplayProductName));
            langKeys = CFArrayCreateMutable(kCFAllocatorDefault, 0,
                                            &kCFTypeArrayCallBacks);
            CFDictionaryApplyFunction(names, KeyArrayCallback, (void *) langKeys);
            orderLangKeys = CFBundleCopyPreferredLocalizationsFromArray(langKeys);
            CFRelease(langKeys);
            if(orderLangKeys && CFArrayGetCount(orderLangKeys)) {
                char		cName[256];
                CFStringRef	langKey;
                CFStringRef	localName;

                langKey = CFArrayGetValueAtIndex(orderLangKeys, 0);
                localName = CFDictionaryGetValue(names, langKey);
                CFStringGetCString(localName, cName, sizeof(cName),
                                    CFStringGetSystemEncoding());
                printf("local name \"%s\"\n", cName);
            }
            CFRelease(orderLangKeys);

            printf("\nAll info:\n");
            CFShow(dict);

            CFRelease(dict);
        }

        // --
        {
            IOCFPlugInInterface ** interface;
            IODisplayCreateInterface( service, kNilOptions,
                                        kIODisplayControlInterfaceID, &interface );
        }
        {
            CFMutableDictionaryRef	dict;
            CFNumberRef			num;
            SInt32 			value;

            dict = CFDictionaryCreateMutable( kCFAllocatorDefault, 0,
                                                &kCFTypeDictionaryKeyCallBacks,
                                                &kCFTypeDictionaryValueCallBacks );

            for( value = 0; value < 0x60; value++) {
                num = CFNumberCreate( kCFAllocatorDefault, kCFNumberSInt32Type, &value );
                CFDictionarySetValue( dict, CFSTR("contrast"), num );
                CFRelease(num);
                err = IODisplaySetParameters( service, kNilOptions, dict );
            }
            CFRelease(dict);
        }
        // --
    }
    
    exit(0);
    return(0);
}