import math
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 ExpressionDefaults, 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]["position"], sprites[f.stem]["faceSize"], servantid)
    print(f"Files have been saved at: {(Paths.OUTPUT / servantid).absolute()}")

def process_sprite(filepath: pathlib.Path, position: tuple, faceSize: int, 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))

    expressionwidth, expressionheight = expressions.size
    rows = expressionheight // faceSize
    expressions_p_row = expressionwidth // faceSize

    exp_per_row = 4

    if faceSize != ExpressionDefaults.faceSize:
        w, h = expressions.size
        composites = []

        per_composite = (1280 - ExpressionDefaults.faceSize) // faceSize
        exp_per_row = per_composite

        offset = (faceSize * ExpressionDefaults.faceSize) / 1280
        composite_count = math.ceil((h - 1280) / (offset + faceSize * per_composite)) + 1

        expressions = expressions.crop((0, 256, w, h))
        floating_offset = 0
        for count in range(0, composite_count + 1):
            composites.append((
                0,
                3 * count * faceSize + floating_offset,
                w,
                (3 * count + 3) * faceSize + floating_offset - 1
            ))
            floating_offset += offset

        overrides = Image.new("RGBA", (w, faceSize * composite_count * 3), (255, 0, 0, 0))
        for idx, c in enumerate(composites):
            crop = expressions.crop(c)
            pos = (
                0,
                idx * 3 * faceSize,
            )
            overrides.paste(crop, pos, crop)
        expressions = overrides.copy()

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

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, faceSize: int) -> Image.Image | None:
    area = (
        col * faceSize,
        row * faceSize,
        (col + 1) * faceSize - 1,
        (row + 1) * faceSize - 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] * rowcol[2] + 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)