//
//  PNG8Image.m
//  Clover
//
//  Created by vector sigma on 07/03/2020.
//  Copyright © 2020 CloverHackyColor. All rights reserved.
//

#import "ThemeImage.h"

@implementation ThemeImage

- (id _Nullable)initWithThemeImageAtPath:(nonnull NSString *)path
                                   error:(NSError *_Nullable*_Nullable)errorPtr {
  if (!(self = [super init])) {
    return nil;
  }
 
  NSData *mainData = [NSData dataWithContentsOfFile: path];
  NSString *domain = @"org.slice.Clover.PNG8Image.Error";
  if (!mainData || [mainData length] < 4) {
    NSString *desc = [NSString stringWithFormat:@"Size of %@ is too small to be an image\n", path];
    NSDictionary *userInfo = @{ NSLocalizedDescriptionKey : desc };
    *errorPtr  = [NSError errorWithDomain:domain
                                     code:1
                                 userInfo:userInfo];
    return nil;
  }
  
  UInt8 * bytes = (UInt8 *)[mainData bytes];
  if (bytes[0] != 0x89 || bytes[0] != 0x50 || bytes[0] != 0x4E || bytes[0] != 0x47) {
    NSBitmapImageRep *bir = [[NSBitmapImageRep alloc] initWithData:mainData];
    if (bir) {
      mainData = [bir representationUsingType:NSPNGFileType properties:[NSDictionary new]];
      if (mainData == nil) {
        NSString *desc = [NSString stringWithFormat:@"Can't convert %@ to png\n", path];
        NSDictionary *userInfo = @{ NSLocalizedDescriptionKey : desc };
        *errorPtr  = [NSError errorWithDomain:domain
                                         code:2
                                     userInfo:userInfo];
        return nil;
      } else {
        [self addRepresentation: [[NSBitmapImageRep alloc] initWithData:mainData]];
      }
    }
  }
  
  unsigned int width, height;
  unsigned char *raw_rgba_pixels;
  
  unsigned int status = lodepng_decode32(&raw_rgba_pixels,
                                         &width,
                                         &height,
                                         [mainData bytes],
                                         [mainData length]);
  
  if (status) {
    NSString *desc = [NSString stringWithFormat:@"%@, %s\n",
                      path,
                      lodepng_error_text(status)];
    NSDictionary *userInfo = @{ NSLocalizedDescriptionKey : desc };
    *errorPtr  = [NSError errorWithDomain:domain
                                     code:3
                                 userInfo:userInfo];
    
    return nil;
  }
  
  // Use libimagequant to make a palette for the RGBA pixels
  liq_attr *handle = liq_attr_create();
  liq_image *input_image = liq_image_create_rgba(handle,
                                                 raw_rgba_pixels,
                                                 width,
                                                 height,
                                                 0);
  // You could set more options here, like liq_set_quality
  liq_result *quantization_result;
  if (liq_image_quantize(input_image, handle, &quantization_result) != LIQ_OK) {
    NSString *desc = [NSString stringWithFormat:@"Quantization failed for %@", path];
    NSDictionary *userInfo = @{ NSLocalizedDescriptionKey : desc };
    *errorPtr  = [NSError errorWithDomain:domain
                                     code:4
                                 userInfo:userInfo];
    return nil;
  }
  
  // Use libimagequant to make new image pixels from the palette
  size_t pixels_size = width * height;
  unsigned char *raw_8bit_pixels = malloc(pixels_size);
  liq_set_dithering_level(quantization_result, 1.0);
  
  liq_write_remapped_image(quantization_result,
                           input_image,
                           raw_8bit_pixels,
                           pixels_size);
  const liq_palette *palette = liq_get_palette(quantization_result);
  
  // Save converted pixels as a PNG file
  // This uses lodepng library for PNG writing (not part of libimagequant)
  LodePNGState state;
  lodepng_state_init(&state);
  state.info_raw.colortype = LCT_PALETTE;
  state.info_raw.bitdepth = 8;
  state.info_png.color.colortype = LCT_PALETTE;
  state.info_png.color.bitdepth = 8;
  
  for(int i = 0; i < palette->count; i++) {
    lodepng_palette_add(&state.info_png.color,
                        palette->entries[i].r,
                        palette->entries[i].g,
                        palette->entries[i].b,
                        palette->entries[i].a);
    
    lodepng_palette_add(&state.info_raw,
                        palette->entries[i].r,
                        palette->entries[i].g,
                        palette->entries[i].b,
                        palette->entries[i].a);
  }
  
  unsigned char *output_file_data;
  size_t output_file_size;
  unsigned int out_status = lodepng_encode(&output_file_data,
                                           &output_file_size,
                                           raw_8bit_pixels,
                                           width,
                                           height,
                                           &state);
  if (out_status) {
    NSString *desc = [NSString stringWithFormat:@"Can't encode %@: %s\n",
                      path,
                      lodepng_error_text(out_status)];
    NSDictionary *userInfo = @{ NSLocalizedDescriptionKey : desc };
    *errorPtr  = [NSError errorWithDomain:domain
                                     code:5
                                 userInfo:userInfo];
    return nil;
  }
  
  // Prove the conversion
  self.pngData = [NSData dataWithBytes: output_file_data length: output_file_size];
  NSImage *convertedImage = [[NSImage alloc] initWithData:self.pngData];
  if (convertedImage == nil) {
    NSString *desc = [NSString stringWithFormat:@"Can't convert data to NSImage (%@)", path];
    NSDictionary *userInfo = @{ NSLocalizedDescriptionKey : desc };
    *errorPtr  = [NSError errorWithDomain:domain
                                     code:6
                                 userInfo:userInfo];
    return nil;
  }
  
  
  liq_result_destroy(quantization_result); // Must be freed only after you're done using the palette
  liq_image_destroy(input_image);
  liq_attr_destroy(handle);
  
  free(raw_8bit_pixels);
  lodepng_state_cleanup(&state);
  
  return self;
}

@end