#!/usr/bin/env python3

import argparse
import json
import os
import subprocess
import sys
from pathlib import Path


ROOT = Path(__file__).resolve().parents[1]
HELPER_PROJECT = ROOT / "tools" / "DtpSnapshotExtractor" / "DtpSnapshotExtractor.csproj"
HELPER_DLL = ROOT / "tools" / "DtpSnapshotExtractor" / "bin" / "Debug" / "net10.0" / "DtpSnapshotExtractor.dll"
DEFAULT_DOTTRACE_DIR = Path.home() / "Applications" / "dotTrace.app" / "Contents" / "DotFiles"


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(
        description="Parse a raw dotTrace .dtp snapshot family into JSON call-tree data."
    )
    parser.add_argument("snapshot", help="Path to the .dtp snapshot index file.")
    parser.add_argument("--out", help="Write JSON to this file.")
    parser.add_argument("--stdout", action="store_true", help="Write JSON to stdout.")
    parser.add_argument("--top", type=int, default=200, help="Maximum hotspot and path entries to emit.")
    parser.add_argument("--filter", dest="name_filter", help="Case-insensitive substring filter for node names.")
    parser.add_argument(
        "--flat",
        "--paths",
        dest="flat_paths",
        action="store_true",
        help="Include the top heaviest call paths as flat strings.",
    )
    idle_group = parser.add_mutually_exclusive_group()
    idle_group.add_argument(
        "--exclude-idle",
        dest="exclude_idle",
        action="store_true",
        default=True,
        help="Exclude idle and wait methods from hotspot and path rankings.",
    )
    idle_group.add_argument(
        "--include-idle",
        dest="exclude_idle",
        action="store_false",
        help="Keep idle and wait methods in hotspot and path rankings.",
    )
    return parser.parse_args()


def find_dottrace_dir() -> Path:
    value = os.environ.get("DOTTRACE_APP_DIR")
    if value:
        candidate = Path(value).expanduser()
        if candidate.is_dir():
            return candidate
    if DEFAULT_DOTTRACE_DIR.is_dir():
        return DEFAULT_DOTTRACE_DIR
    raise FileNotFoundError(
        f"dotTrace assemblies not found. Set DOTTRACE_APP_DIR or install dotTrace under {DEFAULT_DOTTRACE_DIR}."
    )


def build_helper(dottrace_dir: Path) -> None:
    command = [
        "dotnet",
        "build",
        str(HELPER_PROJECT),
        "-nologo",
        "-clp:ErrorsOnly",
        f"-p:DotTraceAppDir={dottrace_dir}",
    ]
    result = subprocess.run(command, cwd=ROOT, capture_output=True, text=True, check=False)
    if result.returncode != 0:
        raise RuntimeError(result.stderr.strip() or result.stdout.strip() or "dotnet build failed")


def run_helper(snapshot: Path, dottrace_dir: Path, args: argparse.Namespace) -> dict:
    command = ["dotnet", str(HELPER_DLL), str(snapshot), "--top", str(args.top)]
    if args.name_filter:
        command.extend(["--filter", args.name_filter])
    if args.flat_paths:
        command.append("--flat")
    if not args.exclude_idle:
        command.append("--include-idle")
    env = os.environ.copy()
    env["DOTTRACE_APP_DIR"] = str(dottrace_dir)
    result = subprocess.run(command, cwd=ROOT, capture_output=True, text=True, check=False, env=env)
    if result.returncode != 0:
        raise RuntimeError(result.stderr.strip() or result.stdout.strip() or "extractor failed")
    return json.loads(result.stdout)


def main() -> int:
    args = parse_args()
    snapshot = Path(args.snapshot).expanduser().resolve()
    if not snapshot.is_file():
        print(f"Snapshot not found: {snapshot}", file=sys.stderr)
        return 2

    if not args.stdout and not args.out:
        args.stdout = True

    try:
        dottrace_dir = find_dottrace_dir()
        build_helper(dottrace_dir)
        payload = run_helper(snapshot, dottrace_dir, args)
    except Exception as exc:  # noqa: BLE001
        print(str(exc), file=sys.stderr)
        return 1

    text = json.dumps(payload, indent=2)
    if args.out:
        out_path = Path(args.out).expanduser().resolve()
        out_path.write_text(text + "\n", encoding="utf-8")
    if args.stdout:
        sys.stdout.write(text + "\n")
    return 0


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