#!/usr/bin/env python3
"""
Clerk pre-push review — spawns the clerk agent to check D-record consistency,
ticket drift, and decision contradictions against the current diff.

Outputs exactly one word to stdout: APPROVED or REJECTED.
Writes verbose findings to .cache/pre-push-review.md.

Exit codes:
  0 = APPROVED
  1 = REJECTED (hard contradiction found)
  2 = TIMEOUT (clerk didn't respond in time — treated as REJECTED)
"""

import os
import subprocess
import sys
import tempfile
from pathlib import Path

REPO_ROOT = Path(subprocess.check_output(
    ["git", "rev-parse", "--show-toplevel"], text=True
).strip())

CACHE_DIR = REPO_ROOT / ".cache"
FINDINGS_FILE = CACHE_DIR / "pre-push-review.md"
TIMEOUT_SECONDS = 120

CLERK_PROMPT = """You are the CLERK, the institutional guardrail for The Settled Reach.

You are reviewing a pre-push diff for D-record consistency, ticket drift, and decision contradictions.

## The diff

{diff}

## Your task

1. Read `decisions/README.md` for the domain index.
2. For each changed file in the diff, check:
   - Does the change contradict any active D-record? (grep decisions/*.md for relevant keywords)
   - If code references a D/Q/R-ID, does that ID exist and is it active?
   - If commits reference ticket #NNN, does the implementation match the ticket description?
3. Surface any open Q-records relevant to changed files.

## Output format

First, write your detailed findings. Then on the VERY LAST LINE of your response,
output exactly one word — either APPROVED or REJECTED.

REJECTED only for hard contradictions with active D-records. Everything else
(drift, open Q-records, suggestions) is a finding but not a block.
"""


def get_diff():
    """Get the diff that would be pushed."""
    branch = subprocess.check_output(
        ["git", "branch", "--show-current"], text=True
    ).strip()

    for ref in [f"origin/{branch}", "origin/main"]:
        try:
            subprocess.check_output(
                ["git", "rev-parse", "--verify", ref],
                stderr=subprocess.DEVNULL, text=True
            )
            return subprocess.check_output(
                ["git", "diff", f"{ref}...HEAD"], text=True
            )
        except subprocess.CalledProcessError:
            continue

    return subprocess.check_output(["git", "diff", "HEAD~1"], text=True)


def run_clerk(diff_text):
    """Spawn clerk via claude --print, return (verdict, findings)."""
    max_diff = 50000
    if len(diff_text) > max_diff:
        diff_text = diff_text[:max_diff] + f"\n\n... (truncated, {len(diff_text)} total chars)"

    prompt = CLERK_PROMPT.format(diff=diff_text)

    with tempfile.NamedTemporaryFile(mode="w", suffix=".txt", delete=False) as f:
        f.write(prompt)
        prompt_file = f.name

    try:
        result = subprocess.run(
            [
                "claude", "-p",
                "--model", "sonnet",
                "--max-turns", "3",
            ],
            input=prompt,
            capture_output=True,
            text=True,
            timeout=TIMEOUT_SECONDS,
            cwd=str(REPO_ROOT),
        )
        output = result.stdout.strip()
    except subprocess.TimeoutExpired:
        return "TIMEOUT", "Clerk agent timed out after {} seconds.".format(TIMEOUT_SECONDS)
    finally:
        os.unlink(prompt_file)

    if not output:
        return "REJECTED", "Clerk agent produced no output."

    lines = output.strip().split("\n")
    last_line = lines[-1].strip().upper()

    if last_line == "APPROVED":
        verdict = "APPROVED"
    elif last_line == "REJECTED":
        verdict = "REJECTED"
    else:
        verdict = "REJECTED"
        output += "\n\n(No clear verdict on last line — defaulting to REJECTED)"

    return verdict, output


def main():
    CACHE_DIR.mkdir(parents=True, exist_ok=True)

    diff_text = get_diff()
    if not diff_text.strip():
        print("APPROVED")
        FINDINGS_FILE.write_text("# Clerk Review\n\nNo diff to review.\n\nVerdict: APPROVED\n")
        return 0

    print("  clerk: reviewing diff...", file=sys.stderr)
    verdict, findings = run_clerk(diff_text)

    FINDINGS_FILE.write_text(f"# Clerk Pre-Push Review\n\n{findings}\n")
    print(f"  clerk: verdict — {verdict} (details: {FINDINGS_FILE})", file=sys.stderr)
    print(verdict)

    if verdict == "APPROVED":
        return 0
    elif verdict == "TIMEOUT":
        return 2
    else:
        return 1


if __name__ == "__main__":
    sys.exit(main())