#!/usr/bin/env python3

import json
import os
import shutil
import subprocess
import tempfile
from multiprocessing.pool import Pool

from PIL import Image as PillowImage


class Image:

    @classmethod
    def thumbnail(cls, args):

        source, target, size = args

        if os.path.exists(target):
            return

        print(f"Generating thumbnail for {source}")

        scratch = tempfile.mkdtemp(prefix="lnxpcs-")
        resized = os.path.join(scratch, "resized.png")

        cls._resize(source, resized, size)
        cls._optimise(resized, target)

        shutil.rmtree(scratch)

    @classmethod
    def _resize(cls, source, target, size):
        try:
            im = PillowImage.open(source)
            im.thumbnail(size)
            im.save(target, "PNG")
        except IOError:
            print(f"Thumbnail creation failed for {source}")

    @classmethod
    def _optimise(cls, source, target):
        subprocess.Popen(
            ["optipng", "-o7", source, "-out", target],
            stdout=subprocess.DEVNULL,
            stderr=subprocess.DEVNULL
        ).wait()


class Prettifier:

    ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
    THUMB_SIZE = (256, 256)

    def __init__(self, columns, threads=None):

        self.columns = columns

        self.threads = threads or int(
            subprocess.check_output(["nproc"]).strip())

    def _generate_headers(self):
        return "| {} |\n| {} |\n".format(
            " | ".join(["" for _ in range(self.columns)]),
            " | ".join([":---:" for _ in range(self.columns)])
        )

    def _generate_image_cell(self, path, base):
        return "![{name}]({path})".format(
            name=path.replace(".png", ""),
            path=os.path.join(".meta", "thumbnails", path)
        )

    def _generate_text_cell(self, path, base):
        """
        Look for a file called ``support.json`` in the ``.meta`` subdirectory
        if it's there, it should have the following format:

        {
          image-name: {
            "shirt": "https://url.to/shirt",
            "mug": "https://hurl.to/mug",
            ...
          },
        }

        Using this file as a guide, we generate the relevant text bits.
        """

        name = path.replace(".png", "")
        r = "[{name}]({path})".format(
            name=name.replace("-", " "),
            path=os.path.join(base, path)
        )

        support = {}
        try:
            support_path = os.path.join(
                self.ROOT,
                base,
                ".meta",
                "support.json"
            )
            with open(support_path) as f:
                support = json.load(f)[name]
        except (FileNotFoundError, KeyError):
            pass

        for key, value in support.items():
            r += f" ([{key}]({value}))"

        return r

    def _generate_thumbnails(self, sources):
        args = []
        for source in sources:
            args.append((
                source,
                os.path.join(
                    os.path.dirname(source),
                    ".meta",
                    "thumbnails",
                    os.path.basename(source)),
                self.THUMB_SIZE
            ))
        with Pool(processes=self.threads) as pool:
            pool.map(Image.thumbnail, args)

    def _generate_rows(self, paths, base):

        this, remainder = paths[:self.columns], paths[self.columns:]

        r = "| {} |\n| {} |\n".format(
            " | ".join([self._generate_image_cell(p, base) for p in this]),
            " | ".join([self._generate_text_cell(p, base) for p in this])
        )

        if remainder:
            r += self._generate_rows(remainder, base)

        return r

    def generate(self, path):
        return self._generate_headers() + self._generate_rows(
            [_ for _ in os.listdir(path) if ".png" in _],
            path.replace(self.ROOT + "/", "")
        )

    @classmethod
    def _get_image_dirs(cls, path):

        r = []
        for path, _, files in os.walk(path):
            if "." in path:
                continue
            for f in files:
                if ".png" in f:
                    r.append(path)
                    break

        return r

    @classmethod
    def main(cls, columns):

        instance = cls(columns)

        originals = []
        for d in cls._get_image_dirs(cls.ROOT):

            thumb_dir = os.path.join(d, ".meta", "thumbnails")
            os.makedirs(thumb_dir, exist_ok=True)

            with open(os.path.join(d, "README.md"), "w") as f:
                f.write(instance.generate(d))

            originals += [os.path.join(d, _) for _ in os.listdir(d) if ".png" in _]  # NOQA: E501

        instance._generate_thumbnails(originals)


if __name__ == "__main__":
    Prettifier.main(4)