#!/usr/bin/env python3
"""The pack's own recipes, as KubeJS really applies them: read from the running test server.

pack/kubejs/server_scripts are code (event.remove with filters, event.shaped, replaceInput, ...),
so the guide does not parse them. Instead this boots the test server (build/server) once on a
throwaway void world and runs `/kubejs export debug` (KubeJS 2101), which reloads the data and
writes local/kubejs/export/:

  recipes/<ns>/<path>.json          every recipe after the scripts ran; the ones a script added or
                                    changed carry "_kubejs_changed_marker": {source, line}
  removed_recipes/<ns>/<path>.json  every recipe a script removed (from mod jars and data packs alike)
  registries/item.json              the item registry, including items KubeJS startup scripts register

The changed recipes, the removed ids and the item ids are copied to build/fieldguide-cache/kubejs-export/
with a hash of the inputs (pack/kubejs scripts and data, pack/mods, datapacks/core).
tools/fieldguide/build.py runs this by itself when that hash no longer matches the pack.

Usage: tools/fieldguide/kubejs_export.py [--accept-eula]   (run tools/build.py first)
"""
import argparse
import hashlib
import json
import os
import shutil
import sys
import time
from pathlib import Path

sys.dont_write_bytecode = True
sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
import mcserver  # noqa: E402

ROOT = mcserver.ROOT
SERVER = mcserver.SERVER
EXPORT = SERVER / "local/kubejs/export"
CACHE = ROOT / "build/fieldguide-cache/kubejs-export"
LEVEL = "fieldguide-export"
MARKER = "_kubejs_changed_marker"
# Inputs that decide the recipe set KubeJS ends up with. Assets (textures, lang) do not.
INPUTS = [ROOT / "pack/kubejs/server_scripts", ROOT / "pack/kubejs/startup_scripts", ROOT / "pack/kubejs/data",
          ROOT / "pack/mods", ROOT / "datapacks/core"]


def input_hash():
    h = hashlib.sha256()
    for base in INPUTS:
        for p in sorted(base.rglob("*")) if base.exists() else []:
            if p.is_file():
                h.update(p.relative_to(ROOT).as_posix().encode() + b"\0" + p.read_bytes() + b"\0")
    return h.hexdigest()


def load():
    """The cached export, or None: {"recipes": {id: json}, "removed": [id], "items": [id], "stale": bool, ...}."""
    path = CACHE / "export.json"
    if not path.exists():
        return None
    data = json.loads(path.read_text())
    data["stale"] = data.pop("inputs") != input_hash()
    return data


def server_busy():
    """True if some process is already running in build/server (another tool's test server)."""
    for proc in Path("/proc").glob("[0-9]*"):
        try:
            if Path(os.readlink(proc / "cwd")) == SERVER.resolve():
                return True
        except OSError:
            continue
    return False


def check_scripts():
    """The server runs build/stage/full's copy of pack/kubejs; refuse to export an older one."""
    differ = []
    for sub in ("server_scripts", "startup_scripts", "data"):
        base = ROOT / "pack/kubejs" / sub
        for p in sorted(base.rglob("*")) if base.exists() else []:
            if p.is_file():
                rel = p.relative_to(ROOT / "pack")
                served = SERVER / rel
                if not served.is_file() or served.read_bytes() != p.read_bytes():
                    differ.append(rel.as_posix())
    if differ:
        raise SystemExit("build/server has an older copy of " + ", ".join(differ) + "; run tools/build.py first")


def export(log=print):
    """Boot the test server, run the KubeJS export, keep the recipe part in the cache. Returns load()."""
    if not mcserver.eula_accepted():
        raise SystemExit("build/server/eula.txt does not accept the Minecraft EULA yet "
                         "(tools/selftest.py --accept-eula writes it if you accept it)")
    if server_busy():
        raise SystemExit("a test server is already running in build/server; try again when it has stopped")
    inputs = input_hash()
    args_file = mcserver.prepare()
    check_scripts()
    shutil.rmtree(SERVER / LEVEL, ignore_errors=True)
    shutil.rmtree(EXPORT, ignore_errors=True)
    flat = '{"layers":[{"block":"minecraft:bedrock","height":1}],"biome":"minecraft:the_void"}'
    props = {"level-name": LEVEL, "level-type": "minecraft:flat", "generator-settings": flat,
             "generate-structures": "false", "spawn-monsters": "false", "spawn-animals": "false"}
    started = time.time()
    with mcserver.Server(args_file, props, stdout_name="fieldguide-export-stdout.log") as server:
        log(f"test server started in {server.wait_ready():.0f}s")
        reply = server.command("kubejs export debug").strip()
        if "exporting" not in reply.lower():
            raise SystemExit(f"/kubejs export debug answered {reply!r}")
        _wait_for_export(server)
        server.stop()
    shutil.rmtree(SERVER / LEVEL, ignore_errors=True)

    recipes = {}
    for p in sorted((EXPORT / "recipes").rglob("*.json")):
        d = json.loads(p.read_text())
        if MARKER in d:
            recipes[_id(p, "recipes")] = d
    removed = sorted(_id(p, "removed_recipes") for p in (EXPORT / "removed_recipes").rglob("*.json"))
    items = sorted(json.loads((EXPORT / "registries/item.json").read_text()))
    kubejs = next((p.name for p in sorted((SERVER / "mods").glob("kubejs-*.jar"))), None)
    CACHE.mkdir(parents=True, exist_ok=True)
    (CACHE / "export.json").write_text(json.dumps({
        "inputs": inputs, "kubejs": kubejs, "exported": time.strftime("%Y-%m-%d %H:%M"),
        "removed": removed, "recipes": recipes, "items": items}, indent=1) + "\n")
    log(f"KubeJS recipes: {len(recipes)} added or changed, {len(removed)} removed ({time.time() - started:.0f}s)")
    return load()


def _id(path, sub):
    """recipes/cobblemon/foo/bar.json -> cobblemon:foo/bar"""
    return path.relative_to(EXPORT / sub).as_posix()[:-5].replace("/", ":", 1)


def _wait_for_export(server, timeout=300):
    """The export reloads first and writes the files afterwards; wait for index.json and every file it lists
    (the index names them by id, cobblemon:foo.json, and the file is cobblemon/foo.json)."""
    deadline = time.time() + timeout
    while time.time() < deadline:
        try:
            listed = json.loads((EXPORT / "index.json").read_text())
            if all((EXPORT / f.replace(":", "/")).exists() for f in listed):
                return
        except (OSError, ValueError):
            pass
        if server.proc.poll() is not None:
            raise SystemExit(f"the test server stopped during the export; see {server.log}")
        time.sleep(1)
    raise SystemExit(f"/kubejs export debug wrote nothing in {timeout}s; see {server.log}")


def main():
    ap = argparse.ArgumentParser(description=__doc__.split("\n")[0])
    ap.add_argument("--accept-eula", action="store_true", help="write eula=true for the test server")
    args = ap.parse_args()
    if args.accept_eula:
        (SERVER / "eula.txt").parent.mkdir(parents=True, exist_ok=True)
        (SERVER / "eula.txt").write_text("eula=true\n")
    data = export()
    for rid in data["removed"]:
        print(f"  - {rid}")
    for rid, d in sorted(data["recipes"].items()):
        print(f"  + {rid}  ({d[MARKER].get('source')}:{d[MARKER].get('line')})")
    print(f"Wrote {CACHE / 'export.json'}")


if __name__ == "__main__":
    main()