/*

 Copyright (C) 2017 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 Controller to managed a picker view displaying imperial weights.

 */

#import "ImperialPickerController.h"

@interface ImperialPickerController () <UIPickerViewDataSource, UIPickerViewDelegate>

@property (nonatomic, strong) IBOutlet UIPickerView *pickerView;

@property (nonatomic, strong) IBOutlet UILabel *label;

@end

#pragma mark -

@implementation ImperialPickerController

// Identifiers and widths for the various components.

#define POUNDS_COMPONENT 0

#define POUNDS_COMPONENT_WIDTH 110

#define POUNDS_LABEL_WIDTH 60

#define OUNCES_COMPONENT 1

#define OUNCES_COMPONENT_WIDTH 106

#define OUNCES_LABEL_WIDTH 56

// Identifies for component views.

#define VIEW_TAG 41

#define SUB_LABEL_TAG 42

#define LABEL_TAG 43

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {

    return 2;

}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {

    // Number of rows depends on the currently-selected unit and the component.

    if (component == POUNDS_COMPONENT) {

        return 29;

    }

    // OUNCES_LABEL_COMPONENT

    return 16;

}

- (UIView *)labelCellWithWidth:(CGFloat)width rightOffset:(CGFloat)offset {

    // Create a new view that contains a label offset from the right.

    CGRect frame = CGRectMake(0.0, 0.0, width, 32.0);

    UIView *view = [[UIView alloc] initWithFrame:frame];

    view.tag = VIEW_TAG;

    frame.size.width = width - offset;

    UILabel *subLabel = [[UILabel alloc] initWithFrame:frame];

    subLabel.textAlignment = NSTextAlignmentRight;

    subLabel.backgroundColor = [UIColor clearColor];

    subLabel.font = [UIFont systemFontOfSize:24.0];

    subLabel.userInteractionEnabled = NO;

    subLabel.tag = SUB_LABEL_TAG;

    [view addSubview:subLabel];

    return view;

}

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view {

    UIView *returnView = nil;

    // Reuse the label if possible, otherwise create and configure a new one.

    if ((view.tag == VIEW_TAG) || (view.tag == LABEL_TAG)) {

        returnView = view;

    }

    else {

        if (component == POUNDS_COMPONENT) {

            returnView = [self labelCellWithWidth:POUNDS_COMPONENT_WIDTH rightOffset:POUNDS_LABEL_WIDTH];

        }

        else {

            returnView = [self labelCellWithWidth:OUNCES_COMPONENT_WIDTH rightOffset:OUNCES_LABEL_WIDTH];

        }

    }

    // The text shown in the component is just the number of the component.

    NSString *text = [NSString stringWithFormat:@"%ld", (long)row];

    // Where to set the text in depends on what sort of view it is.

    UILabel *theLabel = nil;

    if (returnView.tag == VIEW_TAG) {

        theLabel = (UILabel *)[returnView viewWithTag:SUB_LABEL_TAG];

    }

    else {

        theLabel = (UILabel *)returnView;

    }

    theLabel.text = text;

    return returnView;

}

- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component {

    if (component == POUNDS_COMPONENT) {

        return POUNDS_COMPONENT_WIDTH;

    }

    // OUNCES_COMPONENT

    return OUNCES_COMPONENT_WIDTH;

}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {

    // If the user chooses a new row, update the label accordingly.

    [self updateLabel];

}

- (void)updateLabel {

    /*

     If the user has entered imperial units, find the number of pounds and ounces and convert that to kilograms and grams.

     Don't display 0 kg.

     */

    NSInteger ounces = [self.pickerView selectedRowInComponent:OUNCES_COMPONENT];

    ounces += [self.pickerView selectedRowInComponent:POUNDS_COMPONENT] * 16;

    float grams = ounces * 28.349;

    if (grams > 1000.0) {

        NSInteger kg = grams / 1000;

        grams -= kg *1000;

        self.label.text = [NSString stringWithFormat:@"%ld kg  %1.0f g", (long)kg, grams];

    }

    else {

        self.label.text = [NSString stringWithFormat:@"%1.0f g", grams];

    }

}

@end