import pathlib
import sys

import numpy as np
from PIL import Image
from tqdm.contrib import itertools as tqdm_itertools

from .atlas import fetch_data, fetch_image
from .cli import Expressions, Paths


def welcome():
    print("-------------------------------------------------")
    print("  Welcome to the FGO Sprite loader and composer  ")
    print("               developed by Firq                 ")
    print("-------------------------------------------------")

def run():
    welcome()
    Paths.IMAGES.mkdir(exist_ok=True)
    Paths.OUTPUT.mkdir(exist_ok=True)

    servantid = input("Enter servant ID: ")
    try:
        t = int(servantid)
        if t <= 0:
            raise ValueError
    except ValueError:
        print("Servant ID has to be a valid integer above 0")
        sys.exit(1)
    sprites = fetch_data(servantid)

    for sprite in sprites:
        fetch_image(servantid, sprite)

    path = Paths.IMAGES / servantid
    for f in path.iterdir():
        process_sprite(f, sprites[f.stem], servantid)
    print(f"Files have been saved at: {Paths.OUTPUT / servantid}")

def process_sprite(filepath: pathlib.Path, position: tuple, servantid: str):
    im = Image.open(filepath)
    width, height = im.size

    main_sprite = im.crop((0, 0, width, 768))
    save_sprite(main_sprite, servantid, filepath.stem)
    expressions = im.crop((0, 768, width, height))

    _, expressionheight = expressions.size
    rows = expressionheight // Expressions.height

    for x, y in tqdm_itertools.product(range(0, rows), range(0, 4, 1), ascii="-="):
        img = generate_sprite(main_sprite, expressions, x, y, position)
        if img is not None:
            save_sprite(img, servantid, filepath.stem, (x, y))

def is_empty(img: Image.Image):
    data = np.asarray(img.crop((96, 96, 160, 160)).convert('LA'))
    np.reshape(data, (-1, 1))
    _, count_unique = np.unique(data, return_counts=True)
    if count_unique.size < 10:
        return True
    return False

def generate_sprite(sprite: Image.Image, expressions: Image.Image, row: int, col: int, position: tuple) -> Image.Image | None:
    area = (
        col * Expressions.width,
        row * Expressions.height,
        (col + 1) * Expressions.width - 1,
        (row + 1) * Expressions.height - 1
    )

    expression = expressions.crop(area)
    if is_empty(expression):
        return None

    compose = sprite.copy()
    compose.paste(expression, position, expression)
    return compose

def save_sprite(image: Image.Image, folder: str, name: str, rowcol: tuple | None = None):
    savefolder = Paths.OUTPUT / folder
    if not savefolder.is_dir():
        savefolder.mkdir()
    postfix = f"_{rowcol[0] * 4 + rowcol[1] + 1}" if rowcol is not None else "_0"
    outfile = savefolder / f"{name}{postfix}.png"
    with open(outfile, 'wb') as file:
        image.save(file)