#!/usr/bin/env python3
from yaml import safe_load
from pathlib import Path
from sys import argv
import logging
from shlex import quote

path_stickers_root = Path(argv[1])
path_stickers_output_dir = path_stickers_root / 'stickers'
path_stickers_source_dir = path_stickers_root / 'src'
path_makefile_gen = path_stickers_root / 'makefile.gen'
path_stickers_data_dir = path_stickers_root / 'data'
log = logging.getLogger("stickers.make")
logging.basicConfig(
        filename=str(path_stickers_root / 'make.log'),
        level=logging.DEBUG
        )
output_ext = 'static'
out_formats = {
        'static': {
            'extension': 'webp',
            'options': '-lossless 1 -f webp'
            },
        'video': {
            'extension': 'webm',
            'options': '-codec:v libvpx-vp9 -map v -pix_fmt yuva420p'
            },
        'png': {
            'extension': 'png',
            'options': '-preset:v icon -frames 1'
            }
        }

with open(path_makefile_gen, 'w') as makefile:
    targets_list = list()
    # makefile: skeleton rules
    makefile.write(".PHONY: all default clean stickers/\n")
    makefile.write("default: all\n")
    makefile.write('stickers:\n\tmkdir stickers\n')
    makefile.write('clean:\n\trm -vrf stickers\n')
    for sticker_description_file in path_stickers_data_dir.glob('*.yaml'):
        log.debug('input description file: %s', sticker_description_file)
        with open(sticker_description_file) as yaml_file:
            sticker_description = safe_load(yaml_file)
        log.debug("stuff %s", sticker_description)
        target_filename = path_stickers_output_dir \
        / ( sticker_description['name'] \
        + '.' \
        + out_formats[output_ext]['extension'] )
        prerequisite_filename=f"{sticker_description_file} "
        if sticker_description['input']['base'].get('format','') \
        not in ('lavfi', 'image2'):
            prerequisite_filename += str(
                    path_stickers_source_dir \
                    / sticker_description['input']['base']['input']
            ).replace(' ', '\\ ')
        targets_list.append(f"{target_filename}")
        # makefile: rule declaration
        makefile.write(f"{target_filename}: {prerequisite_filename} | stickers\n")
        # makefile: recipe ffmpeg base
        makefile.write('\tffmpeg ')
        # makefile: specify format if present
        if sticker_description['input']['base'].get('format'):
            makefile.write(f"-f {sticker_description['input']['base']['format']} ")
        # makefile: force input framerate if present
        if sticker_description['input']['base'].get('framerate'):
            makefile.write(f"-framerate {sticker_description['input']['base']['framerate']} ")
        #makefile: input base file
        input_file = quote(str(path_stickers_source_dir \
                / sticker_description['input']['base']['input']
                               )
                           )
        makefile.write(f"-i {input_file} ")
        # makefile: video filter: base
        makefile.write('-vf ')
        # makefile: video filter: change transparent color
        if sticker_description['input'].get('colors',{}).get('transparent'):
            makefile.write("geq=\\''")
            transparent = sticker_description['input']['colors']['transparent']
            makefile.write(f"r=if(lt(alpha(X,Y),128),{transparent[0]},r(X,Y)):"
                           f"g=if(lt(alpha(X,Y),128),{transparent[1]},g(X,Y)):"
                           f"b=if(lt(alpha(X,Y),128),{transparent[2]},b(X,Y)):"
                           "a=alpha(X,Y)'\\',"
                    )
        # makefile: video filter: scale
        out_width = sticker_description.get('output', {}).get('width', 512)
        out_height = sticker_description.get('output', {}).get('height', 512)
        makefile.write(f"scale=w={out_width}:h={out_height}:force_original_aspect_ratio=decrease")
        # makefile: output file speed
        if sticker_description.get('output', {}).get('speed'):
            makefile.write(f",setpts={sticker_description['output']['speed']}")
        # makefile: video filter: finalize
        makefile.write(' ')
        # makefile: output file options
        makefile.write(f"{out_formats[output_ext]['options']} ")
        # makefile: replace output without confirmation
        makefile.write('-y ')
        # makefile: output file
        makefile.write(quote(str(target_filename)))
        # makefile: finalize recipe
        makefile.write('\n')
    makefile.write(f"all: {' '.join(targets_list)} | stickers\n")