#!/usr/bin/env python3
import base64
import json
import os
import shutil
import sys
import urllib.error
import urllib.request
from pathlib import Path

PROJECT_ROOT = Path(__file__).resolve().parents[1]
UPROJECT = PROJECT_ROOT / "FunnyGirl.uproject"
DEST = PROJECT_ROOT / "Plugins" / "MobileFSR"
BRANCH = os.environ.get("MOBILE_FSR_BRANCH", "5.6.1-release")
TOKEN = os.environ.get("GITHUB_TOKEN", "")
OWNER = "EpicGames"
REPO = "UnrealEngine"
SOURCE_PATH = "Engine/Plugins/Runtime/MobileFSR"
API_ROOT = f"https://api.github.com/repos/{OWNER}/{REPO}/contents"


def request_json(url):
    request = urllib.request.Request(url)
    request.add_header("Accept", "application/vnd.github+json")
    request.add_header("X-GitHub-Api-Version", "2022-11-28")
    if TOKEN:
        request.add_header("Authorization", f"Bearer {TOKEN}")

    try:
        with urllib.request.urlopen(request) as response:
            return json.loads(response.read().decode("utf-8"))
    except urllib.error.HTTPError as error:
        body = error.read().decode("utf-8", errors="replace")
        raise RuntimeError(f"GitHub API failed: HTTP {error.code}\n{body}") from error


def download_file(api_url, output_path):
    data = request_json(api_url)
    encoding = data.get("encoding")
    content = data.get("content")
    if encoding != "base64" or content is None:
        raise RuntimeError(f"Unsupported file response for {api_url}")

    output_path.parent.mkdir(parents=True, exist_ok=True)
    output_path.write_bytes(base64.b64decode(content))


def download_dir(source_path, output_dir):
    url = f"{API_ROOT}/{source_path}?ref={BRANCH}"
    entries = request_json(url)
    if not isinstance(entries, list):
        raise RuntimeError(f"Expected directory listing for {source_path}")

    for entry in entries:
        name = entry["name"]
        entry_type = entry["type"]
        if entry_type == "dir":
            download_dir(entry["path"], output_dir)
        elif entry_type == "file":
            rel_path = Path(entry["path"]).relative_to(SOURCE_PATH)
            print(f"Downloading {rel_path}")
            download_file(entry["url"], output_dir / rel_path)
        else:
            print(f"Skipping {entry['path']} ({entry_type})")


def enable_plugin():
    data = json.loads(UPROJECT.read_text())
    plugins = data.setdefault("Plugins", [])
    for plugin in plugins:
        if plugin.get("Name") == "MobileFSR":
            plugin["Enabled"] = True
            break
    else:
        plugins.append({"Name": "MobileFSR", "Enabled": True})
    UPROJECT.write_text(json.dumps(data, indent="\t") + "\n")


def main():
    if not TOKEN:
        print("GITHUB_TOKEN is required for private EpicGames/UnrealEngine access.", file=sys.stderr)
        return 1

    tmp_dest = DEST.with_name(".MobileFSR.download")
    shutil.rmtree(tmp_dest, ignore_errors=True)
    shutil.rmtree(DEST, ignore_errors=True)
    tmp_dest.mkdir(parents=True)

    print(f"Downloading MobileFSR from {OWNER}/{REPO}:{BRANCH}")
    download_dir(SOURCE_PATH, tmp_dest)

    if not (tmp_dest / "MobileFSR.uplugin").exists():
        print("MobileFSR.uplugin was not downloaded; aborting.", file=sys.stderr)
        return 1

    shutil.rmtree(DEST, ignore_errors=True)
    shutil.move(str(tmp_dest), str(DEST))
    enable_plugin()

    print(f"Installed MobileFSR to {DEST}")
    print(f"Enabled MobileFSR in {UPROJECT}")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())