//
//  CameraManager.m
//  PanoramicCameraSDK
//
//  Created by 王昭威 on 2023/1/14.
//

#import "CameraManager.h"

@interface CameraManager ()

@property (nonatomic, assign) CGFloat backAspect;

@property (nonatomic, assign) CGFloat frontAspect;

@end

@implementation CameraManager

@synthesize front = _front;
@synthesize back = _back;

- (void)setResolutionFor:(AVCaptureDevicePosition)position with: (NSInteger)desiredWidth{
    
    AVCaptureDevice* device = [self cameraWithPosition:position];
    if(device == nil){
        return;
    }
    
    NSArray *supportedFormats = device.formats;
    
    AVCaptureDeviceFormat *bestFormat;
    CGFloat aspect = 1;
    
    
    for (AVCaptureDeviceFormat *format in supportedFormats) {
        CMVideoDimensions dimensions = CMVideoFormatDescriptionGetDimensions((CMVideoFormatDescriptionRef)[format formatDescription]);
        //分辨率
        if (dimensions.width <= desiredWidth) {
            if(dimensions.height > 0)
                aspect = (CGFloat)dimensions.width / dimensions.height;
            bestFormat = format;
        }
    }
    
    [device lockForConfiguration:nil];
    [device setActiveFormat:bestFormat];
    
    [device setActiveVideoMaxFrameDuration:CMTimeMake(1, 10)];
    [device setActiveVideoMinFrameDuration:CMTimeMake(1, 10)];
    
    [device unlockForConfiguration];
    
    if(device.position == AVCaptureDevicePositionFront){
        self.frontAspect = aspect;
    }
    else if(device.position == AVCaptureDevicePositionBack){
        self.backAspect = aspect;
    }
}


- (AVCaptureDevice *)cameraWithPosition:(AVCaptureDevicePosition)position
{
    NSArray *devices = nil;
    if(@available(iOS 10, *)){
        AVCaptureDeviceDiscoverySession *captureDeviceDiscoverySession = [AVCaptureDeviceDiscoverySession discoverySessionWithDeviceTypes:@[AVCaptureDeviceTypeBuiltInWideAngleCamera]
                                              mediaType:AVMediaTypeVideo
                                               position:position];
        devices = [captureDeviceDiscoverySession devices];
    }
    else if(@available(iOS 4, *)){
        devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    }
    if(devices == nil){
        return nil;
    }
    for (AVCaptureDevice *device in devices)
    {
        if ([device position] == position)
            return device;
    }
    return nil;
}

+ (instancetype)shared{
    static dispatch_once_t token;
    static CameraManager* instance = nil;
    dispatch_once(&token, ^{
        instance = [[self alloc] init];
    });
    
    return instance;
}

- (instancetype)init{
    self = [super init];
    if(self){
        _back = [self cameraWithPosition:AVCaptureDevicePositionBack];
        _front = [self cameraWithPosition:AVCaptureDevicePositionFront];
        
        _frontAspect = 1;
        _backAspect = 1;
    }
    
    return self;
}

- (void)focusOn:(CGPoint)point{
    if (self.back == nil) {
        return;
    }
    [self focusOn:point device:self.back];
}

- (void)focusOn:(CGPoint)point device:(AVCaptureDevice *)device{
    NSError* error;
    [device lockForConfiguration:&error];
    if(error != nil){
        return;
    }
    
    if ([device isFocusModeSupported:AVCaptureFocusModeContinuousAutoFocus]){
        [device setFocusPointOfInterest: point];
        device.focusMode = AVCaptureFocusModeContinuousAutoFocus;
    }
    if ([device isExposureModeSupported:AVCaptureExposureModeContinuousAutoExposure]) {
        [device setExposurePointOfInterest:point];
        device.exposureMode = AVCaptureExposureModeContinuousAutoExposure;
    }
    [device unlockForConfiguration];
}


@end