#!/usr/bin/env python3

import os
import shutil
import re
import yaml

from operator import attrgetter, itemgetter
from pathlib import Path

from jinja2 import Environment, PackageLoader, select_autoescape
from PIL import Image

from configuration import OUTPUT_DIR, PICTURES_DIR, SIZES, THEME_DIR


jinja_env = Environment(
    loader=PackageLoader("revelateur", THEME_DIR),
    autoescape=select_autoescape(["html"]),
)


def neighborhood(iterable, first=None, last=None):
    """
    Yield the (previous, current, next) items given an iterable.

    You can specify a `first` and/or `last` item for bounds.
    """
    iterator = iter(iterable)
    previous = first
    current = next(iterator)  # Throws StopIteration if empty.
    for next_ in iterator:
        yield (previous, current, next_)
        previous = current
        current = next_
    yield (previous, current, last)


def list_galleries_in(path):
    gallery_dirs = [f for f in os.scandir(path) if f.is_dir()]
    for gallery_dir in gallery_dirs:
        gallery_path = Path(gallery_dir.path)
        metadata = {}
        metadata_path = gallery_path / "metadata.yml"
        if metadata_path.exists():
            metadata = yaml.safe_load(metadata_path.read_text())

        private = False
        slug = gallery_dir.name
        password = metadata.get("password", None)
        if password:
            private = True
            slug = f"{slug}-{password}"

        photos = list(list_photos_in(gallery_dir, metadata, slug))
        if not photos:
            continue
        photos.sort(key=itemgetter("name"))

        cover_photo = find_photo(photos, metadata.get("cover", "01"))

        gallery = {
            "name": metadata.get("name", gallery_dir.name),
            "type": metadata.get("type", "photo"),
            "path": gallery_path,
            "slug": slug,
            "photos": photos,
            "cover_photo": cover_photo,
            "private": private,
        }
        yield gallery


def find_photo(photos, photo_name):
    for photo in photos:
        if photo["name"] == photo_name:
            return photo
    return None


def list_photos_in(gallery_dir, gallery_metadata, gallery_slug):
    photo_files = [
        f for f in os.scandir(gallery_dir) if re.match(".+\.jpg", f.name, re.I)
    ]
    for photo_file in sorted(photo_files, key=attrgetter("name")):
        with Image.open(photo_file.path) as image:
            width, height = image.size
        name = Path(photo_file.name).stem
        metadata = gallery_metadata.get(name, {})
        page_url = f"{gallery_slug}-{name}.html"
        photo = {
            "gallery_slug": gallery_slug,
            "name": name,
            "path": photo_file.path,
            "url": Path(gallery_slug) / photo_file.name,
            "page_url": page_url,
            "width": width,
            "height": height,
            "narrow": height > width,
            "wide": height * 2 < width,
            "alt": metadata.get("alt", ""),
        }
        yield photo


def create_output_dir():
    if not OUTPUT_DIR.exists():
        os.mkdir(OUTPUT_DIR)


def copy_theme_folder(name, target=None):
    local_path = THEME_DIR / name
    output_path = OUTPUT_DIR / (target if target is not None else name)
    if output_path.exists() and target is None:
        shutil.rmtree(output_path)
    shutil.copytree(local_path, output_path, dirs_exist_ok=True)


def generate_index(output_path, galleries):
    index_template = jinja_env.get_template("index.html.j2")
    content = index_template.render(galleries=galleries, sizes=SIZES)
    (OUTPUT_DIR / "index.html").write_text(content)


def generate_gallery(output_path, gallery):
    generate_gallery_photos(output_path, gallery)
    generate_gallery_pages(output_path, gallery)


def generate_gallery_pages(output_path, gallery):
    photo_template = jinja_env.get_template("media.html.j2")

    for previous, photo, next_ in neighborhood(gallery["photos"]):
        content = photo_template.render(
            photo=photo, previous=previous, next=next_, gallery=gallery, sizes=SIZES
        )
        (OUTPUT_DIR / photo["page_url"]).write_text(content)


def generate_gallery_photos(output_path, gallery):
    gallery_output_path_jpg = output_path / gallery["slug"] / "jpg"
    gallery_output_path_webp = output_path / gallery["slug"] / "webp"
    os.makedirs(gallery_output_path_jpg, exist_ok=True)
    os.makedirs(gallery_output_path_webp, exist_ok=True)

    for photo in gallery["photos"]:
        # Let's not share the original file for now.
        # photo_output_path = output_path / photo["url"]
        # if not photo_output_path.exists():
        #     shutil.copyfile(photo["path"], photo_output_path)

        for width, height in SIZES:
            jpg_output_path = generate_jpg_photo_for_size(
                gallery_output_path_jpg, photo, width, height
            )
            generate_webp_photo_for_size(
                gallery_output_path_webp, jpg_output_path, photo, width, height
            )


def generate_webp_photo_for_size(
    gallery_output_path, jpg_output_path, photo, width, height
):
    output_path = gallery_output_path / f"{photo['name']}_{width}x{height}.webp"

    if output_path.exists():
        return

    image = Image.open(jpg_output_path)
    image.save(output_path, format="webp", icc_profile=image.info.get("icc_profile"))


def generate_jpg_photo_for_size(gallery_output_path, photo, width, height):
    output_path = gallery_output_path / f"{photo['name']}_{width}x{height}.jpg"

    if output_path.exists():
        return output_path

    image = Image.open(photo["path"])
    image.thumbnail((width, height), resample=Image.LANCZOS)
    image.save(output_path, icc_profile=image.info.get("icc_profile"))

    return output_path


def main():
    print("Loading galleries... ", end="")
    galleries = list(list_galleries_in(PICTURES_DIR))
    if not galleries:
        print(f"No galleries found in {PICTURES_DIR}")
        return
    galleries.sort(key=itemgetter("path"), reverse=True)
    print(f"{len(galleries)} galleries found.")

    print("Creating output folder... ", end="")
    create_output_dir()
    print("✔️")
    print("Copying style folder... ", end="")
    copy_theme_folder("style")
    print("✔️")
    print("Copying scripts folder... ", end="")
    copy_theme_folder("scripts")
    print("✔️")
    print("Copying root (favicon, etc) folder... ", end="")
    copy_theme_folder("root", "")
    print("✔️")
    print("Generating index file... ", end="")
    generate_index(OUTPUT_DIR, galleries)
    print("✔️")
    for gallery in galleries:
        print(
            (
                f"Generating {gallery['name']} gallery "
                f"(http://localhost:8080/{gallery['cover_photo']['page_url']})... "
            ),
            end="",
        )
        generate_gallery(OUTPUT_DIR, gallery)
        print("✔️")
    print("Galleries generated 🎉")


if __name__ == "__main__":
    main()