"""Detect tool, run init + plan, capture output."""
from __future__ import annotations

import re
import subprocess
from pathlib import Path
from typing import Literal

from scripts.manifest import InitResult, PlanResult


Tool = Literal["terragrunt", "tofu"]

_TAIL_BYTES = 4096
_SUMMARY_RE = re.compile(
    r"Plan:\s+(\d+\s+to add,\s*\d+\s+to change,\s*\d+\s+to destroy)\."
)


def detect_tool(plan_dir: Path | str) -> Tool:
    p = Path(plan_dir)
    if (p / "terragrunt.hcl").is_file():
        return "terragrunt"
    return "tofu"


def _tail(s: str, n: int = _TAIL_BYTES) -> str:
    return s[-n:] if len(s) > n else s


def extract_summary(plan_stdout: str) -> str:
    m = _SUMMARY_RE.search(plan_stdout)
    if m:
        return re.sub(r"\s+", " ", m.group(1)).strip()
    if "No changes." in plan_stdout or "no changes." in plan_stdout.lower():
        return "no changes"
    return "unknown"


def run_init(plan_dir: Path | str, tool: Tool) -> InitResult:
    args = [tool, "init", "-input=false", "-no-color"]
    result = subprocess.run(
        args, cwd=str(plan_dir), capture_output=True, text=True, check=False,
    )
    return InitResult(
        ok=(result.returncode == 0),
        stdout_tail=_tail(result.stdout),
        stderr_tail=_tail(result.stderr),
    )


def run_plan(plan_dir: Path | str, tool: Tool, stdout_path: Path) -> PlanResult:
    args = [tool, "plan", "-input=false", "-no-color"]
    result = subprocess.run(
        args, cwd=str(plan_dir), capture_output=True, text=True, check=False,
    )
    stdout_path.parent.mkdir(parents=True, exist_ok=True)
    stdout_path.write_text(result.stdout)
    return PlanResult(
        ok=(result.returncode == 0),
        stdout_path=str(stdout_path),
        exit_code=result.returncode,
        summary=extract_summary(result.stdout),
    )