#!/usr/bin/env python3
"""Apply border recoloring to side/front frames; copy top frames as-is.

Input:  final_data/sim_NNNNN/frames/{front,side,top}/frame_NNNNN.png
Output: final_data_processed/sim_NNNNN/frames/{front,side,top}/frame_NNNNN.png
"""
from __future__ import annotations

import os
import shutil
from pathlib import Path

import numpy as np
from PIL import Image

# ── constants (from prepare.py / cvae_sph2img) ───────────────────────────────
PURE_GREEN           = np.array([0, 197, 0],   dtype=np.uint8)
PURE_BLUE            = np.array([0, 0, 189],   dtype=np.uint8)
PURE_BLACK           = np.array([0, 0, 0],     dtype=np.uint8)
PURE_GRAY            = np.array([98, 93, 90],  dtype=np.uint8)
BORDER_THICKNESS_PX  = 10
SIDE_BOTTOM_HEIGHT_PX = 188
SIDE_BUFFER          = 3

# ── image processing ──────────────────────────────────────────────────────────

def detect_side_columns(rgb: np.ndarray) -> tuple[int, int]:
    h, w, _ = rgb.shape
    if h == 0 or w == 0:
        return (0, 0)
    probe_y = max(0, h - SIDE_BOTTOM_HEIGHT_PX)
    row = rgb[probe_y, :, :3]
    mask = np.all(row == PURE_BLACK, axis=1) | np.all(row == PURE_GRAY, axis=1)
    left = 0
    while left < w and mask[left]:
        left += 1
    right = 0
    idx = w - 1
    while idx >= 0 and mask[idx]:
        right += 1
        idx -= 1
    return (left, right)


def fixed_border_recolor(rgb: np.ndarray, left_columns: int, right_columns: int) -> np.ndarray:
    out = rgb[:, :, :3].copy()
    h, w, _ = out.shape
    bt  = min(BORDER_THICKNESS_PX, h, w)
    sbh = min(SIDE_BOTTOM_HEIGHT_PX, h)
    out[:bt, :, :]  = PURE_BLUE
    out[h - bt:, :, :] = PURE_GREEN
    if left_columns > 0:
        lw = min(left_columns, w)
        out[:, :lw, :]          = PURE_BLUE
        out[h - sbh:, :lw, :]  = PURE_GREEN
    if right_columns > 0:
        rw = min(right_columns, w)
        out[:, w - rw:, :]         = PURE_BLUE
        out[h - sbh:, w - rw:, :]  = PURE_GREEN
    return out


def process_image(src: Path, dst: Path, is_side: bool) -> None:
    rgb = np.array(Image.open(src).convert("RGB"))
    h, w, _ = rgb.shape
    default_cols = min(BORDER_THICKNESS_PX, h, w)
    if is_side:
        left, right = detect_side_columns(rgb)
        if left  > 0: left  = min(w, left  + SIDE_BUFFER)
        if right > 0: right = min(w, right + SIDE_BUFFER)
    else:
        left, right = default_cols, default_cols
    out = fixed_border_recolor(rgb, left, right)
    Image.fromarray(out).save(dst)


# ── main ──────────────────────────────────────────────────────────────────────

def main() -> None:
    here        = Path(__file__).parent
    src_root    = here / "final_data"
    dst_root    = here / "final_data_processed"

    sim_dirs = sorted(src_root.iterdir())
    print(f"Found {len(sim_dirs)} simulations")

    for sim_dir in sim_dirs:
        if not sim_dir.is_dir():
            continue
        frames_src = sim_dir / "frames"
        if not frames_src.is_dir():
            print(f"  SKIP {sim_dir.name} — no frames/ directory")
            continue

        for view in ("front", "side", "top"):
            view_src = frames_src / view
            view_dst = dst_root / sim_dir.name / "frames" / view
            if not view_src.is_dir():
                continue
            view_dst.mkdir(parents=True, exist_ok=True)

            for png in sorted(view_src.glob("*.png")):
                dst_path = view_dst / png.name
                if view == "top":
                    shutil.copy2(png, dst_path)
                else:
                    process_image(png, dst_path, is_side=(view == "side"))

        print(f"  {sim_dir.name} done")

    print("All done.")


if __name__ == "__main__":
    main()