"""JSON output generator — structured path data from PostProcessResult."""

from __future__ import annotations

import json

from pipeline.postprocess import PathInfo, PostProcessResult


def _path_to_dict(path: PathInfo) -> dict:
    """Convert a PathInfo to a JSON-serializable dict with path commands."""
    commands = []
    coords = path.simplified_coords
    if not coords:
        return {"commands": [], "properties": {}}

    # Move to start
    commands.append({"type": "M", "x": coords[0][0], "y": coords[0][1]})

    # Line to each subsequent point
    for x, y in coords[1:]:
        commands.append({"type": "L", "x": x, "y": y})

    # Close if applicable
    if path.is_closed:
        commands.append({"type": "Z"})

    properties = {
        "is_closed": path.is_closed,
        "is_island": path.is_island,
        "node_count": path.node_count,
        "original_node_count": path.original_node_count,
        "area": round(path.area, 4),
    }

    return {"commands": commands, "properties": properties}


def generate_json(result: PostProcessResult) -> str:
    """Generate a JSON string from post-processed path data.

    Output format:
    {
        "paths": [
            {
                "commands": [{"type": "M", "x": 0, "y": 0}, {"type": "L", "x": 10, "y": 0}, ...],
                "properties": {"is_closed": true, "is_island": false, ...}
            },
            ...
        ],
        "metadata": {
            "path_count": 2,
            "total_nodes": 10,
            "total_original_nodes": 50,
            "open_path_count": 0,
            "island_count": 1
        }
    }

    Args:
        result: PostProcessResult from the post-processing pipeline.

    Returns:
        JSON string.
    """
    output = {
        "paths": [_path_to_dict(p) for p in result.paths],
        "metadata": {
            "path_count": len(result.paths),
            "total_nodes": result.total_nodes,
            "total_original_nodes": result.total_original_nodes,
            "open_path_count": result.open_path_count,
            "island_count": result.island_count,
        },
    }
    return json.dumps(output, indent=2)