#!/usr/bin/env python3
"""
Rearrange PowerPoint slides based on a sequence of indices.

Usage:
    python rearrange.py template.pptx output.pptx 0,34,34,50,52

This will create output.pptx using slides from template.pptx in the specified order.
Slides can be repeated (e.g., 34 appears twice).
"""

metadata = {
    "id": "code:document.pptx.rearrange",
    "name": "PPTX Rearrange Slides",
    "description": "Rearrange PowerPoint slides based on a sequence of indices",
    "language": "python",
    "packages": ["python-pptx", "six"],
    "args": [
        {"name": "template_pptx", "type": "string", "description": "Path to template PowerPoint file", "position": 0},
        {"name": "output_pptx", "type": "string", "description": "Output PowerPoint file path", "position": 1},
        {"name": "slide_indices", "type": "string", "description": "Comma-separated slide indices (e.g., 0,34,34,50,52)", "position": 2}
    ]
}

import argparse
import shutil
import sys
from copy import deepcopy
from pathlib import Path

import six
from pptx import Presentation


def main():
    parser = argparse.ArgumentParser(
        description="Rearrange PowerPoint slides based on a sequence of indices.",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog="""
Examples:
  python rearrange.py template.pptx output.pptx 0,34,34,50,52
    Creates output.pptx using slides 0, 34 (twice), 50, and 52 from template.pptx

  python rearrange.py template.pptx output.pptx 5,3,1,2,4
    Creates output.pptx with slides reordered as specified

Note: Slide indices are 0-based (first slide is 0, second is 1, etc.)
        """,
    )

    parser.add_argument("template", help="Path to template PPTX file")
    parser.add_argument("output", help="Path for output PPTX file")
    parser.add_argument(
        "sequence", help="Comma-separated sequence of slide indices (0-based)"
    )

    args = parser.parse_args()

    # Parse the slide sequence
    try:
        slide_sequence = [int(x.strip()) for x in args.sequence.split(",")]
    except ValueError:
        print(
            "Error: Invalid sequence format. Use comma-separated integers (e.g., 0,34,34,50,52)"
        )
        sys.exit(1)

    # Check template exists
    template_path = Path(args.template)
    if not template_path.exists():
        print(f"Error: Template file not found: {args.template}")
        sys.exit(1)

    # Create output directory if needed
    output_path = Path(args.output)
    output_path.parent.mkdir(parents=True, exist_ok=True)

    try:
        rearrange_presentation(template_path, output_path, slide_sequence)
    except ValueError as e:
        print(f"Error: {e}")
        sys.exit(1)
    except Exception as e:
        print(f"Error processing presentation: {e}")
        sys.exit(1)


def duplicate_slide(pres, index):
    """Duplicate a slide in the presentation."""
    source = pres.slides[index]

    # Use source's layout to preserve formatting
    new_slide = pres.slides.add_slide(source.slide_layout)

    # Collect all image and media relationships from the source slide
    image_rels = {}
    for rel_id, rel in six.iteritems(source.part.rels):
        if "image" in rel.reltype or "media" in rel.reltype:
            image_rels[rel_id] = rel

    # CRITICAL: Clear placeholder shapes to avoid duplicates
    for shape in new_slide.shapes:
        sp = shape.element
        sp.getparent().remove(sp)

    # Copy all shapes from source
    for shape in source.shapes:
        el = shape.element
        new_el = deepcopy(el)
        new_slide.shapes._spTree.insert_element_before(new_el, "p:extLst")

        # Handle picture shapes - need to update the blip reference
        # Look for all blip elements (they can be in pic or other contexts)
        # Using the element's own xpath method without namespaces argument
        blips = new_el.xpath(".//a:blip[@r:embed]")
        for blip in blips:
            old_rId = blip.get(
                "{http://schemas.openxmlformats.org/officeDocument/2006/relationships}embed"
            )
            if old_rId in image_rels:
                # Create a new relationship in the destination slide for this image
                old_rel = image_rels[old_rId]
                # get_or_add returns the rId directly, or adds and returns new rId
                new_rId = new_slide.part.rels.get_or_add(
                    old_rel.reltype, old_rel._target
                )
                # Update the blip's embed reference to use the new relationship ID
                blip.set(
                    "{http://schemas.openxmlformats.org/officeDocument/2006/relationships}embed",
                    new_rId,
                )

    # Copy any additional image/media relationships that might be referenced elsewhere
    for rel_id, rel in image_rels.items():
        try:
            new_slide.part.rels.get_or_add(rel.reltype, rel._target)
        except Exception:
            pass  # Relationship might already exist

    return new_slide


def delete_slide(pres, index):
    """Delete a slide from the presentation."""
    rId = pres.slides._sldIdLst[index].rId
    pres.part.drop_rel(rId)
    del pres.slides._sldIdLst[index]


def reorder_slides(pres, slide_index, target_index):
    """Move a slide from one position to another."""
    slides = pres.slides._sldIdLst

    # Remove slide element from current position
    slide_element = slides[slide_index]
    slides.remove(slide_element)

    # Insert at target position
    slides.insert(target_index, slide_element)


def rearrange_presentation(template_path, output_path, slide_sequence):
    """
    Create a new presentation with slides from template in specified order.

    Args:
        template_path: Path to template PPTX file
        output_path: Path for output PPTX file
        slide_sequence: List of slide indices (0-based) to include
    """
    # Copy template to preserve dimensions and theme
    if template_path != output_path:
        shutil.copy2(template_path, output_path)
        prs = Presentation(output_path)
    else:
        prs = Presentation(template_path)

    total_slides = len(prs.slides)

    # Validate indices
    for idx in slide_sequence:
        if idx < 0 or idx >= total_slides:
            raise ValueError(f"Slide index {idx} out of range (0-{total_slides - 1})")

    # Track original slides and their duplicates
    slide_map = []  # List of actual slide indices for final presentation
    duplicated = {}  # Track duplicates: original_idx -> [duplicate_indices]

    # Step 1: DUPLICATE repeated slides
    print(f"Processing {len(slide_sequence)} slides from template...")
    for i, template_idx in enumerate(slide_sequence):
        if template_idx in duplicated and duplicated[template_idx]:
            # Already duplicated this slide, use the duplicate
            slide_map.append(duplicated[template_idx].pop(0))
            print(f"  [{i}] Using duplicate of slide {template_idx}")
        elif slide_sequence.count(template_idx) > 1 and template_idx not in duplicated:
            # First occurrence of a repeated slide - create duplicates
            slide_map.append(template_idx)
            duplicates = []
            count = slide_sequence.count(template_idx) - 1
            print(
                f"  [{i}] Using original slide {template_idx}, creating {count} duplicate(s)"
            )
            for _ in range(count):
                duplicate_slide(prs, template_idx)
                duplicates.append(len(prs.slides) - 1)
            duplicated[template_idx] = duplicates
        else:
            # Unique slide or first occurrence already handled, use original
            slide_map.append(template_idx)
            print(f"  [{i}] Using original slide {template_idx}")

    # Step 2: DELETE unwanted slides (work backwards)
    slides_to_keep = set(slide_map)
    print(f"\nDeleting {len(prs.slides) - len(slides_to_keep)} unused slides...")
    for i in range(len(prs.slides) - 1, -1, -1):
        if i not in slides_to_keep:
            delete_slide(prs, i)
            # Update slide_map indices after deletion
            slide_map = [idx - 1 if idx > i else idx for idx in slide_map]

    # Step 3: REORDER to final sequence
    print(f"Reordering {len(slide_map)} slides to final sequence...")
    for target_pos in range(len(slide_map)):
        # Find which slide should be at target_pos
        current_pos = slide_map[target_pos]
        if current_pos != target_pos:
            reorder_slides(prs, current_pos, target_pos)
            # Update slide_map: the move shifts other slides
            for i in range(len(slide_map)):
                if slide_map[i] > current_pos and slide_map[i] <= target_pos:
                    slide_map[i] -= 1
                elif slide_map[i] < current_pos and slide_map[i] >= target_pos:
                    slide_map[i] += 1
            slide_map[target_pos] = target_pos

    # Save the presentation
    prs.save(output_path)
    print(f"\nSaved rearranged presentation to: {output_path}")
    print(f"Final presentation has {len(prs.slides)} slides")


if __name__ == "__main__":
    main()