#!/usr/bin/env nix-shell
#!nix-shell -p nix -p python3 -p git -i python
# USAGE - just run the script: ./update.py
# When editing this file, make also sure it passes the mypy typecheck
# and is formatted with black.
import fileinput
import json
import re
import subprocess
import tempfile
import urllib.request
from datetime import datetime
from pathlib import Path
from typing import Dict

SCRIPT_DIR = Path(__file__).parent.resolve()


def sh(*args: str) -> str:
    out = subprocess.check_output(list(args))
    return out.strip().decode("utf-8")


def prefetch_github(owner: str, repo: str, ref: str) -> str:
    return sh(
        "nix-prefetch-url",
        "--unpack",
        f"https://github.com/{owner}/{repo}/archive/{ref}.tar.gz",
    )


def get_radare2_rev() -> str:
    url = "https://api.github.com/repos/radare/radare2/releases/latest"
    with urllib.request.urlopen(url) as response:
        release = json.load(response)  # type: ignore
    return release["tag_name"]


def get_cutter_version() -> str:
    version_expr = """
(with import <nixpkgs> {}; (builtins.parseDrvName (qt5.callPackage ./cutter.nix {}).name).version)
"""
    with SCRIPT_DIR:
        return sh("nix", "eval", "--raw", version_expr.strip())


def get_r2_cutter_rev() -> str:
    version = get_cutter_version()
    url = f"https://api.github.com/repos/radareorg/cutter/contents?ref=v{version}"
    with urllib.request.urlopen(url) as response:
        data = json.load(response)  # type: ignore
    for entry in data:
        if entry["name"] == "radare2":
            return entry["sha"]
    raise Exception("no radare2 submodule found in github.com/radareorg/cutter")


def git(dirname: str, *args: str) -> str:
    return sh("git", "-C", dirname, *args)


def get_repo_info(dirname: str, rev: str) -> Dict[str, str]:
    sha256 = prefetch_github("radare", "radare2", rev)

    cs_tip = None
    with open(Path(dirname).joinpath("shlr", "Makefile")) as makefile:
        for l in makefile:
            match = re.match("CS_TIP=(\S+)", l)
            if match:
                cs_tip = match.group(1)
    assert cs_tip is not None

    cs_sha256 = prefetch_github("aquynh", "capstone", cs_tip)

    return dict(
        rev=rev,
        sha256=sha256,
        version_commit=git(dirname, "rev-list", "--all", "--count"),
        gittap=git(dirname, "describe", "--tags", "--match", "[0-9]*"),
        gittip=git(dirname, "rev-parse", "HEAD"),
        cs_tip=cs_tip,
        cs_sha256=cs_sha256,
    )


def write_package_expr(version: str, info: Dict[str, str]) -> str:
    return f"""generic {{
    version_commit = "{info["version_commit"]}";
    gittap = "{info["gittap"]}";
    gittip = "{info["gittip"]}";
    rev = "{info["rev"]}";
    version = "{version}";
    sha256 = "{info["sha256"]}";
    cs_tip = "{info["cs_tip"]}";
    cs_sha256 = "{info["cs_sha256"]}";
  }}"""


def main() -> None:
    radare2_rev = get_radare2_rev()
    r2_cutter_rev = get_r2_cutter_rev()

    with tempfile.TemporaryDirectory() as dirname:
        git(
            dirname,
            "clone",
            "--branch",
            radare2_rev,
            "https://github.com/radare/radare2",
            ".",
        )
        nix_file = str(Path(__file__).parent.joinpath("default.nix"))

        radare2_info = get_repo_info(dirname, radare2_rev)

        git(dirname, "checkout", r2_cutter_rev)

        timestamp = git(dirname, "log", "-n1", "--format=%at")
        r2_cutter_version = datetime.fromtimestamp(int(timestamp)).strftime("%Y-%m-%d")

        r2_cutter_info = get_repo_info(dirname, r2_cutter_rev)

        in_block = False
        with fileinput.FileInput(nix_file, inplace=True) as f:
            for l in f:
                if "#<generated>" in l:
                    in_block = True
                    print(
                        f"""  #<generated>
  # DO NOT EDIT! Automatically generated by ./update.py
  radare2 = {write_package_expr(radare2_rev, radare2_info)};
  r2-for-cutter = {write_package_expr(r2_cutter_version, r2_cutter_info)};
  #</generated>"""
                    )
                elif "#</generated>" in l:
                    in_block = False
                elif not in_block:
                    print(l, end="")


if __name__ == "__main__":
    main()