#!/usr/bin/env python3
"""
Generate an MCC BlockPalette C# file from server-generated blocks.json.

The blocks.json file is generated by running:
    java -DbundlerMainClass=net.minecraft.data.Main -jar server.jar --reports

Usage:
    python3 tools/gen_block_palette.py <blocks.json> <suffix>

Example:
    python3 tools/gen_block_palette.py /tmp/mc_reports/reports/blocks.json 1219
    # Generates Palette1219.cs
"""

import json
import re
import sys
from pathlib import Path

OUTPUT_DIR = (Path(__file__).resolve().parent.parent /
              "MinecraftClient" / "Mapping" / "BlockPalettes")
MATERIAL_CS = OUTPUT_DIR.parent / "Material.cs"


def mc_name_to_csharp(mc_name: str) -> str:
    """Convert minecraft:snake_case to PascalCase C# enum name."""
    name = mc_name.removeprefix("minecraft:")
    return "".join(word.capitalize() for word in name.split("_"))


def load_known_materials() -> set[str]:
    known = set()
    if MATERIAL_CS.exists():
        with open(MATERIAL_CS) as f:
            for line in f:
                m = re.match(r'\s+(\w+),?\s*$', line)
                if m:
                    known.add(m.group(1))
    return known


def main():
    if len(sys.argv) != 3:
        print(__doc__)
        sys.exit(1)

    blocks_json = Path(sys.argv[1])
    class_suffix = sys.argv[2]

    if not blocks_json.exists():
        print(f"Error: {blocks_json} not found")
        sys.exit(1)

    with open(blocks_json) as f:
        data = json.load(f)

    # Build (min_state, max_state, cs_name) for each block, sorted by min_state
    block_ranges = []
    for block_key, block_info in data.items():
        cs_name = mc_name_to_csharp(block_key)
        states = block_info.get("states", [])
        state_ids = [s["id"] for s in states]
        if state_ids:
            block_ranges.append((min(state_ids), max(state_ids), cs_name))

    block_ranges.sort(key=lambda x: x[0])
    print(f"Loaded {len(block_ranges)} blocks from {blocks_json}")

    max_state = max(r[1] for r in block_ranges)
    print(f"State ID range: 0 - {max_state}")

    known_materials = load_known_materials()
    missing = [cs for _, _, cs in block_ranges if known_materials and cs not in known_materials]
    if missing:
        print(f"\nWARNING: {len(missing)} blocks not found in Material.cs enum:")
        for cs_name in missing:
            print(f"  {cs_name}")
        print("\nYou need to add these to Material.cs before the palette will compile.")
        print("Insert them in alphabetical order within the enum.")

    class_name = f"Palette{class_suffix}"
    output_path = OUTPUT_DIR / f"{class_name}.cs"

    lines = [
        "using System.Collections.Generic;",
        "",
        "namespace MinecraftClient.Mapping.BlockPalettes",
        "{",
        f"    public class {class_name} : BlockPalette",
        "    {",
        "        private static readonly Dictionary<int, Material> materials = new();",
        "",
        f"        static {class_name}()",
        "        {",
    ]

    for min_s, max_s, cs_name in block_ranges:
        lines.append(f"            for (int i = {min_s}; i <= {max_s}; i++)")
        lines.append(f"                materials[i] = Material.{cs_name};")

    lines += [
        "        }",
        "",
        "        protected override Dictionary<int, Material> GetDict()",
        "        {",
        "            return materials;",
        "        }",
        "    }",
        "}",
        "",
    ]

    output_path.write_text("\n".join(lines))
    print(f"Generated {output_path} with {len(block_ranges)} blocks ({max_state + 1} total states)")


if __name__ == "__main__":
    main()