"""Create thumbnail grids from PowerPoint presentation slides.

Creates a grid layout of slide thumbnails for quick visual analysis.
Labels each thumbnail with its XML filename (e.g., slide1.xml).
Hidden slides are shown with a placeholder pattern.

Usage:
    python thumbnail.py input.pptx [output_prefix] [--cols N]

Examples:
    python thumbnail.py presentation.pptx
    # Creates: thumbnails.jpg

    python thumbnail.py template.pptx grid --cols 4
    # Creates: grid.jpg (or grid-1.jpg, grid-2.jpg for large decks)
"""

import argparse
import posixpath
import subprocess
import sys
import tempfile
import zipfile
from pathlib import Path

import defusedxml.minidom
from defusedxml import ElementTree
from office.helpers import SLIDE_REL_TYPE, opc_target
from office.soffice import run_soffice
from PIL import Image, ImageDraw, ImageFont


THUMBNAIL_WIDTH = 300
CONVERSION_DPI = 100
MAX_COLS = 6
DEFAULT_COLS = 3
JPEG_QUALITY = 95
GRID_PADDING = 20
BORDER_WIDTH = 2
FONT_SIZE_RATIO = 0.10
LABEL_PADDING_RATIO = 0.4


def main():
    parser = argparse.ArgumentParser(
        description="Create thumbnail grids from PowerPoint slides."
    )
    parser.add_argument("input", help="Input PowerPoint file (.pptx)")
    parser.add_argument(
        "output_prefix",
        nargs="?",
        default="thumbnails",
        help="Output prefix for image files (default: thumbnails)",
    )
    parser.add_argument(
        "--cols",
        type=int,
        default=DEFAULT_COLS,
        help=f"Number of columns (default: {DEFAULT_COLS}, max: {MAX_COLS})",
    )

    args = parser.parse_args()

    cols = min(args.cols, MAX_COLS)
    if args.cols > MAX_COLS:
        print(f"Warning: Columns limited to {MAX_COLS}")

    input_path = Path(args.input)
    if not input_path.exists() or input_path.suffix.lower() != ".pptx":
        print(f"Error: Invalid PowerPoint file: {args.input}", file=sys.stderr)
        sys.exit(1)

    output_path = Path(f"{args.output_prefix}.jpg")

    try:
        slide_info = get_slide_info(input_path)

        with tempfile.TemporaryDirectory() as temp_dir:
            temp_path = Path(temp_dir)
            visible_images = convert_to_images(input_path, temp_path)

            if not visible_images and not any(s["hidden"] for s in slide_info):
                print("Error: No slides found", file=sys.stderr)
                sys.exit(1)

            slides = build_slide_list(slide_info, visible_images, temp_path)

            grid_files = create_grids(slides, cols, THUMBNAIL_WIDTH, output_path)

            print(f"Created {len(grid_files)} grid(s):")
            for grid_file in grid_files:
                print(f"  {grid_file}")

    except Exception as e:
        print(f"Error: {e}", file=sys.stderr)
        sys.exit(1)


def _is_hidden(zf: zipfile.ZipFile, part: str) -> bool:
    try:
        with zf.open(part) as f:
            for _, root in ElementTree.iterparse(f, events=("start",)):
                return root.get("show") in ("0", "false")  
    except (KeyError, ElementTree.ParseError):
        return False
    return False


def get_slide_info(pptx_path: Path) -> list[dict]:
    with zipfile.ZipFile(pptx_path, "r") as zf:
        rels_content = zf.read("ppt/_rels/presentation.xml.rels").decode("utf-8")
        rels_dom = defusedxml.minidom.parseString(rels_content)

        rid_to_part = {}
        for rel in rels_dom.getElementsByTagName("Relationship"):
            if rel.getAttribute("Type") != SLIDE_REL_TYPE:
                continue
            part = opc_target(
                rel.getAttribute("Target"),
                "ppt/presentation.xml",
                rel.getAttribute("TargetMode"),
            )
            if part is not None:
                rid_to_part[rel.getAttribute("Id")] = part

        pres_content = zf.read("ppt/presentation.xml").decode("utf-8")
        pres_dom = defusedxml.minidom.parseString(pres_content)

        present = set(zf.namelist())

        slides = []
        for sld_id in pres_dom.getElementsByTagName("p:sldId"):
            part = rid_to_part.get(sld_id.getAttribute("r:id"))
            if part is not None and part in present:
                slides.append(
                    {"name": posixpath.basename(part), "hidden": _is_hidden(zf, part)}
                )

        return slides


def build_slide_list(
    slide_info: list[dict],
    visible_images: list[Path],
    temp_dir: Path,
) -> list[tuple[Path, str]]:
    visible_count = sum(1 for info in slide_info if not info["hidden"])
    rendered_hidden = len(visible_images) == len(slide_info) != visible_count

    if not rendered_hidden and visible_count != len(visible_images):
        raise ValueError(
            f"LibreOffice rendered {len(visible_images)} page(s) for {visible_count} "
            f"visible slide(s) of {len(slide_info)}; thumbnails would be mislabeled"
        )

    if visible_images:
        with Image.open(visible_images[0]) as img:
            placeholder_size = img.size
    else:
        placeholder_size = (1920, 1080)

    slides = []
    visible_idx = 0

    for info in slide_info:
        if info["hidden"] and not rendered_hidden:
            placeholder_path = temp_dir / f"hidden-{info['name']}.jpg"
            placeholder_img = create_hidden_placeholder(placeholder_size)
            placeholder_img.save(placeholder_path, "JPEG")
            slides.append((placeholder_path, f"{info['name']} (hidden)"))
        else:
            label = f"{info['name']} (hidden)" if info["hidden"] else info["name"]
            slides.append((visible_images[visible_idx], label))
            visible_idx += 1

    return slides


def create_hidden_placeholder(size: tuple[int, int]) -> Image.Image:
    img = Image.new("RGB", size, color="#F0F0F0")
    draw = ImageDraw.Draw(img)
    line_width = max(5, min(size) // 100)
    draw.line([(0, 0), size], fill="#CCCCCC", width=line_width)
    draw.line([(size[0], 0), (0, size[1])], fill="#CCCCCC", width=line_width)
    return img


def convert_to_images(pptx_path: Path, temp_dir: Path) -> list[Path]:
    pdf_path = temp_dir / f"{pptx_path.stem}.pdf"

    result = run_soffice(
        ["--headless", "--convert-to", "pdf", "--outdir", str(temp_dir), str(pptx_path)],
        capture_output=True,
        text=True,
    )
    if result.returncode != 0 or not pdf_path.exists():
        detail = (result.stderr or result.stdout or "").strip()
        raise RuntimeError(f"PDF conversion failed: {detail}" if detail else "PDF conversion failed")

    result = subprocess.run(
        [
            "pdftoppm",
            "-jpeg",
            "-r",
            str(CONVERSION_DPI),
            str(pdf_path),
            str(temp_dir / "slide"),
        ],
        capture_output=True,
        text=True,
    )
    if result.returncode != 0:
        raise RuntimeError("Image conversion failed")

    return sorted(temp_dir.glob("slide-*.jpg"))


def create_grids(
    slides: list[tuple[Path, str]],
    cols: int,
    width: int,
    output_path: Path,
) -> list[str]:
    max_per_grid = cols * (cols + 1)
    grid_files = []

    for chunk_idx, start_idx in enumerate(range(0, len(slides), max_per_grid)):
        end_idx = min(start_idx + max_per_grid, len(slides))
        chunk_slides = slides[start_idx:end_idx]

        grid = create_grid(chunk_slides, cols, width)

        if len(slides) <= max_per_grid:
            grid_filename = output_path
        else:
            stem = output_path.stem
            suffix = output_path.suffix
            grid_filename = output_path.parent / f"{stem}-{chunk_idx + 1}{suffix}"

        grid_filename.parent.mkdir(parents=True, exist_ok=True)
        grid.save(str(grid_filename), quality=JPEG_QUALITY)
        grid_files.append(str(grid_filename))

    return grid_files


def create_grid(
    slides: list[tuple[Path, str]],
    cols: int,
    width: int,
) -> Image.Image:
    font_size = int(width * FONT_SIZE_RATIO)
    label_padding = int(font_size * LABEL_PADDING_RATIO)

    with Image.open(slides[0][0]) as img:
        aspect = img.height / img.width
    height = int(width * aspect)

    rows = (len(slides) + cols - 1) // cols
    grid_w = cols * width + (cols + 1) * GRID_PADDING
    grid_h = rows * (height + font_size + label_padding * 2) + (rows + 1) * GRID_PADDING

    grid = Image.new("RGB", (grid_w, grid_h), "white")
    draw = ImageDraw.Draw(grid)

    try:
        font = ImageFont.load_default(size=font_size)
    except Exception:
        font = ImageFont.load_default()

    for i, (img_path, slide_name) in enumerate(slides):
        row, col = i // cols, i % cols
        x = col * width + (col + 1) * GRID_PADDING
        y_base = (
            row * (height + font_size + label_padding * 2) + (row + 1) * GRID_PADDING
        )

        label = slide_name
        bbox = draw.textbbox((0, 0), label, font=font)
        text_w = bbox[2] - bbox[0]
        draw.text(
            (x + (width - text_w) // 2, y_base + label_padding),
            label,
            fill="black",
            font=font,
        )

        y_thumbnail = y_base + label_padding + font_size + label_padding

        with Image.open(img_path) as img:
            img.thumbnail((width, height), Image.Resampling.LANCZOS)
            w, h = img.size
            tx = x + (width - w) // 2
            ty = y_thumbnail + (height - h) // 2
            grid.paste(img, (tx, ty))

            if BORDER_WIDTH > 0:
                draw.rectangle(
                    [
                        (tx - BORDER_WIDTH, ty - BORDER_WIDTH),
                        (tx + w + BORDER_WIDTH - 1, ty + h + BORDER_WIDTH - 1),
                    ],
                    outline="gray",
                    width=BORDER_WIDTH,
                )

    return grid


if __name__ == "__main__":
    main()