"""Image conversion utilities for ATOMS3 MacroPad."""

import math
import os
import random
import shutil
from PIL import Image, ImageTk
from .constants import SCREEN_W, SCREEN_H, IMAGES_DIR


def ensure_images_dir():
    os.makedirs(IMAGES_DIR, exist_ok=True)


def generate_gradient_image() -> str:
    """Generate a random linear gradient PNG, save it to images dir, return its path."""
    ensure_images_dir()

    c1 = (random.randint(30, 220), random.randint(30, 220), random.randint(30, 220))
    c2 = (random.randint(30, 220), random.randint(30, 220), random.randint(30, 220))
    angle = math.radians(random.randint(0, 359))
    cos_a = math.cos(angle)
    sin_a = math.sin(angle)

    size = SCREEN_W  # 128x128 to match device display
    img = Image.new("RGB", (size, size))
    pixels = img.load()
    for y in range(size):
        for x in range(size):
            nx = (x / (size - 1)) * 2 - 1
            ny = (y / (size - 1)) * 2 - 1
            t = max(0.0, min(1.0, (nx * cos_a + ny * sin_a + 1) / 2))
            pixels[x, y] = (
                int(c1[0] + (c2[0] - c1[0]) * t),
                int(c1[1] + (c2[1] - c1[1]) * t),
                int(c1[2] + (c2[2] - c1[2]) * t),
            )

    token = "%08x" % random.getrandbits(32)
    path = os.path.join(IMAGES_DIR, f"gradient_{token}.png")
    img.save(path)
    return path


def copy_image_to_appdata(image_path: str) -> str:
    """Copy an image to the AppData images folder, return new path."""
    ensure_images_dir()
    basename = os.path.basename(image_path)
    # Hash-suffix the filename to avoid collisions between same-named imports
    name, ext = os.path.splitext(basename)
    import hashlib
    h = hashlib.md5(open(image_path, "rb").read()).hexdigest()[:8]
    dest = os.path.join(IMAGES_DIR, f"{name}_{h}{ext}")
    if not os.path.exists(dest):
        shutil.copy2(image_path, dest)
    return dest


def convert_to_rgb565(image_path: str) -> bytes:
    """Convert image to 128x128 RGB565 big-endian bytes (32768 bytes)."""
    img = Image.open(image_path).convert("RGB")
    img = img.resize((SCREEN_W, SCREEN_H), Image.LANCZOS)

    data = bytearray(SCREEN_W * SCREEN_H * 2)
    pixels = img.load()

    for y in range(SCREEN_H):
        for x in range(SCREEN_W):
            r, g, b = pixels[x, y]
            rgb565 = ((r & 0xF8) << 8) | ((g & 0xFC) << 3) | (b >> 3)
            offset = (y * SCREEN_W + x) * 2
            data[offset] = (rgb565 >> 8) & 0xFF      # MSB
            data[offset + 1] = rgb565 & 0xFF          # LSB

    return bytes(data)


def create_thumbnail(image_path: str, size: tuple = (64, 64)):
    """Create a tkinter-compatible thumbnail from an image file."""
    img = Image.open(image_path).convert("RGB")
    img.thumbnail(size, Image.LANCZOS)
    return ImageTk.PhotoImage(img)


def create_preview(image_path: str, size: tuple = (128, 128)):
    """Larger preview image for the properties panel."""
    img = Image.open(image_path).convert("RGB")
    img = img.resize(size, Image.LANCZOS)
    return ImageTk.PhotoImage(img)