#!/usr/bin/env python3
"""Write the island world type from world/biomes.json.

Vanilla's overworld biome parameters come from Minecraft's own data generator
(run on the vanilla server jar that the NeoForge installer put in
build/server; no server is started). Every entry is sent to its target biome
from world/biomes.json, the extra entries are appended, and the result becomes
the inline biome list of WorldGen Editor's delegate in
datapacks/core/data/cobblesurvival/worldgen/world_preset/island.json.

The world type has no Nether dimension.

Usage: tools/biome_layout.py      (run tools/smoke_test.py once first so build/server exists)
"""
import json
import subprocess
import sys
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parent))
from mcserver import CACHE, PACK, ROOT, SERVER  # noqa: E402
from packwiz_sync import java  # noqa: E402

PRESET = ROOT / "datapacks/core/data/cobblesurvival/worldgen/world_preset/island.json"


def vanilla_parameters():
    version = PACK["versions"]["minecraft"]
    report = CACHE / f"datagen-{version}" / "reports/biome_parameters/minecraft/overworld.json"
    if not report.exists():
        jar = SERVER / "libraries/net/minecraft/server" / version / f"server-{version}.jar"
        if not jar.exists():
            sys.exit(f"{jar} is missing; run tools/smoke_test.py once so the NeoForge installer fetches it")
        work = CACHE / f"datagen-{version}"
        work.mkdir(parents=True, exist_ok=True)
        subprocess.run([java(), "-DbundlerMainClass=net.minecraft.data.Main", "-jar", str(jar),
                        "--reports", "--output", str(work)], cwd=work, check=True, stdout=subprocess.DEVNULL)
    return json.loads(report.read_text())["biomes"]


def main():
    spec = json.loads((ROOT / "world/biomes.json").read_text())
    targets = set(spec["allowed"]) | set(spec["water"])
    entries, unmapped = [], set()
    for entry in vanilla_parameters():
        target = spec["remap"].get(entry["biome"])
        if target is None:
            unmapped.add(entry["biome"])
            continue
        entries.append({"biome": target, "parameters": entry["parameters"]})
    for extra in spec["add"]:
        entries.append({"biome": extra["biome"], "parameters": extra["parameters"]})
    bad_targets = {e["biome"] for e in entries} - targets
    if unmapped or bad_targets:
        sys.exit(f"vanilla biomes without a target: {sorted(unmapped)}; targets outside the list: {sorted(bad_targets)}")

    preset = {
        "dimensions": {
            "minecraft:overworld": {
                "type": "minecraft:overworld",
                "generator": {
                    "type": "minecraft:noise",
                    "biome_source": {
                        "type": "worldgen_editor:island_biome_source",
                        "preset": "cobblesurvival_island",
                        "delegate": {"type": "minecraft:multi_noise", "biomes": "@BIOMES@"},
                    },
                    "settings": "worldgen_editor:island_overworld",
                },
            },
            "minecraft:the_end": {
                "type": "minecraft:the_end",
                "generator": {"type": "minecraft:noise", "biome_source": {"type": "minecraft:the_end"},
                              "settings": "minecraft:end"},
            },
        }
    }
    # One biome entry per line keeps the 7,600-entry file diffable.
    body = ",\n".join("            " + json.dumps(e, separators=(",", ":")) for e in entries)
    text = json.dumps(preset, indent=2).replace('"@BIOMES@"', "[\n" + body + "\n          ]")
    json.loads(text)
    PRESET.write_text(text + "\n")
    counts = {}
    for e in entries:
        counts[e["biome"]] = counts.get(e["biome"], 0) + 1
    print(f"wrote {PRESET.relative_to(ROOT)}: {len(entries)} entries")
    for biome, n in sorted(counts.items(), key=lambda kv: -kv[1]):
        print(f"  {n:5}  {biome}")


if __name__ == "__main__":
    main()