#!/usr/bin/env python3
"""
agent_loop.py — called from cron every 10 minutes.

Flow
----
1. Agent already running?
   a. Age > 1 h  → kill it, set its issue to State/Question, exit 1
   b. Age ≤ 1 h  → print status, exit 0  (let it keep working)
2. No agent running → extract pending_issue from state (if any), then check CI
   a. CI is running         → save pending-ci state, exit 0
   b. Latest CI failed      → start fix-CI agent (preserving pending_issue), exit 0
   c. CI ok + pending_issue → close the issue (CI passed), exit 0
   d. CI ok (or no run yet) → find oldest Ready issue, start issue agent,
                              save state, exit 0
   e. No Ready issues       → print "nothing to do", exit 0

Issue agents must NOT close the issue themselves; the loop closes it after CI passes.

State file: ~/.sharedinbox-agent-state.json
  { "pid": 12345, "issue": 91,
    "started_at": "2026-05-15T12:00:00+00:00", "type": "issue" }

Output is written to ~/.sharedinbox-agent-logs/<session>-<timestamp>.log.
Resume the Claude conversation afterward with:

  claude --resume issue-91
"""

import argparse
import json
import os
import shlex
import subprocess
import sys
from datetime import datetime, timezone
from pathlib import Path

# Cron runs with a minimal PATH; ensure Nix profile binaries (tea, claude) and ~/go/bin (fgj) are found.
os.environ["PATH"] = (
    f"{Path.home()}/.nix-profile/bin"
    f":{Path.home()}/go/bin"
    f":{os.environ.get('PATH', '/usr/bin:/bin')}"
)

# ── configuration ─────────────────────────────────────────────────────────────

REPO = "guettli/sharedinbox"
REPO_URL = f"https://codeberg.org/{REPO}"
STATE_FILE = Path.home() / ".sharedinbox-agent-state.json"
MAX_AGENT_AGE_SECONDS = 3600  # 1 hour
CLAUDE_PROJECTS_DIR = Path.home() / ".claude" / "projects" / (
    "-" + str(Path.home())[1:].replace("/", "-")
)

# Labels used by the workflow.
LABEL_READY = "State/Ready"
LABEL_IN_PROGRESS = "State/InProgress"
LABEL_QUESTION = "State/Question"
LABEL_PRIO_HIGH = "Prio/High"

# Only pick up issues filed by these accounts.
ALLOWED_ISSUE_AUTHORS = {"guettli", "guettlibot", "guettlibot2"}

# ── helpers ───────────────────────────────────────────────────────────────────


def _issue_url(number: int) -> str:
    return f"{REPO_URL}/issues/{number}"


def _ci_run_url(run_id: int) -> str:
    return f"{REPO_URL}/actions/runs/{run_id}"


def _fgj(*args: str) -> None:
    """Run a fgj command, raising on failure."""
    cmd = ["fgj", "--hostname", "codeberg.org", *args]
    result = subprocess.run(cmd, capture_output=True, text=True)
    if result.returncode != 0:
        raise RuntimeError(
            f"fgj {' '.join(args)} failed:\n{result.stderr or result.stdout}"
        )


def _tea_get(path: str) -> dict | list | None:
    """Run a tea api GET and return parsed JSON. Only use for reads — tea PATCH/PUT
    silently fails (exits 0) when unauthenticated, so writes must go via fgj."""
    cmd = ["tea", "api", path]
    result = subprocess.run(cmd, capture_output=True, text=True)
    if result.returncode != 0:
        raise RuntimeError(
            f"tea api {path} failed:\n{result.stderr or result.stdout}"
        )
    out = result.stdout.strip()
    if not out:
        return None
    data = json.loads(out)
    if isinstance(data, dict) and "message" in data and "url" in data:
        raise RuntimeError(f"tea api {path} returned error: {data['message']}")
    return data


def _set_labels(issue: int, add: list[str], remove: list[str]) -> None:
    """Add/remove labels on an issue via fgj."""
    cmd = ["issue", "edit", str(issue), "--repo", REPO]
    for label in add:
        cmd += ["--add-label", label]
    for label in remove:
        cmd += ["--remove-label", label]
    _fgj(*cmd)


def _close_issue(issue: int) -> None:
    _fgj("issue", "close", str(issue), "--repo", REPO)
    _set_labels(issue, add=[], remove=[LABEL_IN_PROGRESS])


def _comment_issue(issue: int, body: str) -> None:
    _fgj("issue", "comment", str(issue), "--repo", REPO, "--body", body)


def _ready_issues() -> list[dict]:
    """Return open issues with State/Ready, Prio/High first, then oldest."""
    result = subprocess.run(
        ["fgj", "--hostname", "codeberg.org", "issue", "list",
         "--repo", REPO, "--state", "open", "--json"],
        capture_output=True, text=True, check=True,
    )
    data = json.loads(result.stdout) if result.stdout.strip() else []
    ready = [
        i for i in data
        if any(lbl["name"] == LABEL_READY for lbl in i.get("labels", []))
        and i.get("user", {}).get("login", "") in ALLOWED_ISSUE_AUTHORS
    ]
    ready.sort(key=lambda i: (
        0 if any(lbl["name"] == LABEL_PRIO_HIGH for lbl in i.get("labels", [])) else 1,
        i["number"],
    ))
    return ready


def _latest_ci_run() -> dict | None:
    data = _tea_get(f"repos/{REPO}/actions/runs?limit=1")
    runs = (data or {}).get("workflow_runs", [])
    return runs[0] if runs else None


def _latest_ci_run_for_branch(branch: str) -> dict | None:
    """Return the latest CI run for a specific branch, or None.

    Forgejo's workflow_runs API has no top-level head_branch field.
    For push events the branch is in ``prettyref``; for pull_request
    events it lives inside ``event_payload["pull_request"]["head"]["ref"]``.
    """
    data = _tea_get(f"repos/{REPO}/actions/runs?limit=20")
    runs = (data or {}).get("workflow_runs", [])
    for run in runs:
        if run.get("event") == "pull_request":
            try:
                payload = json.loads(run.get("event_payload", "{}"))
                if payload.get("pull_request", {}).get("head", {}).get("ref") == branch:
                    return run
            except (json.JSONDecodeError, AttributeError):
                pass
        else:
            if run.get("prettyref") == branch:
                return run
    return None


def _find_pr_for_branch(branch: str) -> dict | None:
    """Return the first open PR whose head branch matches, or None."""
    result = subprocess.run(
        ["fgj", "--hostname", "codeberg.org", "pr", "list",
         "--repo", REPO, "--state", "open", "--json"],
        capture_output=True, text=True,
    )
    if result.returncode != 0 or not result.stdout.strip():
        return None
    prs = json.loads(result.stdout)
    for pr in prs:
        head = pr.get("head", {})
        ref = head.get("ref") or head.get("label", "").split(":")[-1]
        if ref == branch:
            return pr
    return None


def _merge_pr(pr_number: int) -> None:
    """Squash-merge a PR via fgj."""
    _fgj("pr", "merge", str(pr_number), "--repo", REPO, "--merge-method", "squash")


# ── state file ────────────────────────────────────────────────────────────────


def _read_state() -> dict | None:
    if STATE_FILE.exists():
        try:
            return json.loads(STATE_FILE.read_text())
        except Exception:
            pass
    return None


def _write_state(pid: int | None, issue: int | None, kind: str, issue_title: str | None = None, session_name: str | None = None, ci_run_id: int | None = None) -> None:
    data: dict = {
        "pid": pid,
        "issue": issue,
        "started_at": datetime.now(timezone.utc).isoformat(),
        "type": kind,
    }
    if issue_title is not None:
        data["issue_title"] = issue_title
    if session_name is not None:
        data["session_name"] = session_name
    if ci_run_id is not None:
        data["ci_run_id_at_start"] = ci_run_id
    STATE_FILE.write_text(json.dumps(data, indent=2))
    STATE_FILE.chmod(0o600)


def _clear_state() -> None:
    STATE_FILE.unlink(missing_ok=True)


# ── agent launcher ────────────────────────────────────────────────────────────


def _start_agent(prompt: str, session_name: str) -> int:
    """Start Claude Code as a detached background process and return its PID."""
    log_dir = Path.home() / ".sharedinbox-agent-logs"
    log_dir.mkdir(mode=0o700, exist_ok=True)
    log_dir.chmod(0o700)  # fix permissions if dir already existed with wrong mode
    ts = datetime.now().strftime("%Y%m%dT%H%M%S")
    log_file = log_dir / f"{session_name}-{ts}.log"

    log_fh = open(log_file, "w", opener=lambda p, f: os.open(p, f, 0o600))
    proc = subprocess.Popen(
        [
            "claude",
            "--dangerously-skip-permissions",
            "--name", session_name,
            "-p", prompt,
        ],
        stdin=subprocess.PIPE,
        stdout=log_fh,
        stderr=log_fh,
        start_new_session=True,
    )
    log_fh.close()  # Parent closes its copy; the child retains the fd.
    # Answer the workspace-trust dialog; after this the pipe hits EOF.
    proc.stdin.write(b"\n")
    proc.stdin.close()

    print(f"Started agent pid={proc.pid}, log={log_file}")
    print(f"  Resume: claude --resume {shlex.quote(session_name)}")
    return proc.pid


def _agent_alive(state: dict) -> bool:
    """Return True if the agent process is still running."""
    pid = state.get("pid")
    if pid is None:
        return False
    try:
        os.kill(pid, 0)
        return True
    except ProcessLookupError:
        return False
    except PermissionError:
        return True


def _agent_age_seconds(state: dict) -> float:
    """Seconds elapsed since the agent was launched, from the state file timestamp."""
    try:
        started_at = datetime.fromisoformat(state["started_at"])
        return (datetime.now(timezone.utc) - started_at).total_seconds()
    except Exception:
        return 0.0


def _git_summary() -> str:
    """Return a one-line summary of the latest commit and whether it's been pushed."""
    try:
        commit = subprocess.run(
            ["git", "log", "--oneline", "-1"],
            capture_output=True, text=True, check=True,
        ).stdout.strip()
        ahead = subprocess.run(
            ["git", "rev-list", "--count", "HEAD@{u}..HEAD"],
            capture_output=True, text=True,
        )
        if ahead.returncode == 0 and ahead.stdout.strip() != "0":
            push_status = f"not pushed ({ahead.stdout.strip()} ahead)"
        elif ahead.returncode == 0:
            push_status = "pushed"
        else:
            push_status = "no upstream"
        return f"{commit} [{push_status}]"
    except Exception:
        return ""


def _kill_agent(state: dict) -> None:
    """Forcefully stop the running agent."""
    pid = state.get("pid")
    if pid:
        try:
            os.kill(pid, 9)
        except ProcessLookupError:
            pass


# ── subcommands ───────────────────────────────────────────────────────────────


def cmd_list() -> int:
    """List recent agent-loop sessions, newest first."""
    if not CLAUDE_PROJECTS_DIR.exists():
        print(f"No sessions found (directory missing: {CLAUDE_PROJECTS_DIR})")
        return 0

    sessions = []
    for jsonl in CLAUDE_PROJECTS_DIR.glob("*.jsonl"):
        agent_name = None
        session_id = None
        try:
            with jsonl.open() as fh:
                for line in fh:
                    line = line.strip()
                    if not line:
                        continue
                    d = json.loads(line)
                    if d.get("type") == "agent-name":
                        agent_name = d.get("agentName")
                        session_id = d.get("sessionId")
                        break
        except Exception:
            continue
        if agent_name:
            sessions.append((jsonl.stat().st_mtime, agent_name, session_id))

    if not sessions:
        print("No agent sessions found.")
        return 0

    sessions.sort(reverse=True)
    total = len(sessions)
    print(f"  {'DATE':<16}  {'NAME':<20}  UUID  (use with: claude --resume <uuid>)")
    print(f"  {'-'*16}  {'-'*20}  {'-'*36}")
    for mtime, name, sid in sessions[:20]:
        ts = datetime.fromtimestamp(mtime).strftime("%Y-%m-%d %H:%M")
        print(f"  {ts:<16}  {name:<20}  {sid}")
    if total > 20:
        print(f"  ... ({total - 20} more)")
    return 0


# ── main flow ─────────────────────────────────────────────────────────────────


def _run_loop() -> int:
    now = datetime.now(timezone.utc)
    print(f"---------------------- Starting {now.strftime('%Y-%m-%d %H:%MZ')}")

    state = _read_state()

    # ── 1. Agent already running? ─────────────────────────────────────────────
    if state and _agent_alive(state):
        age = _agent_age_seconds(state)
        issue = state.get("issue")
        kind = state.get("type", "issue")
        pid = state.get("pid", "?")

        issue_title = state.get("issue_title", "")
        issue_ref = (
            f"{_issue_url(issue)} {issue_title}".strip() if issue else str(issue)
        )

        if age > MAX_AGENT_AGE_SECONDS:
            print(
                f"Agent pid={pid!r} ({issue_ref}) "
                f"has been running for {age/60:.0f} min — aborting."
            )
            _kill_agent(state)
            _clear_state()
            if issue:
                _set_labels(issue, add=[LABEL_QUESTION], remove=[LABEL_IN_PROGRESS])
                _comment_issue(
                    issue,
                    f"Agent (pid {pid}) was killed after running for {age/60:.0f} min "
                    f"(limit: {MAX_AGENT_AGE_SECONDS//60} min). "
                    "Please investigate and resume manually.",
                )
                print(f"Set {_issue_url(issue)} to State/Question.")
            return 1

        session_name = state.get("session_name")
        resume_cmd = f"claude --resume {shlex.quote(session_name)}" if session_name else ""
        git_info = _git_summary()
        parts = [
            f"Agent pid={pid!r} ({kind}, {issue_ref}) still running ({age/60:.0f} min). Waiting.",
        ]
        if resume_cmd:
            parts.append(f"  Resume: {resume_cmd}")
        if git_info:
            parts.append(f"  Commit: {git_info}")
        print("\n".join(parts))
        return 0

    # Agent not running (or no state) — extract any pending issue, then clean up.
    pending_issue: int | None = None
    ci_run_id_at_start: int | None = None
    if state:
        pending_issue = state.get("issue")
        ci_run_id_at_start = state.get("ci_run_id_at_start")
        _clear_state()

    # ── 2. Check for a PR opened by the agent ────────────────────────────────
    if pending_issue:
        branch = f"issue-{pending_issue}-fix"
        pr = _find_pr_for_branch(branch)
        if pr:
            pr_number = pr["number"]
            pr_url = f"{REPO_URL}/pulls/{pr_number}"
            print(f"Found PR #{pr_number} ({pr_url}) for issue #{pending_issue}.")
            pr_run = _latest_ci_run_for_branch(branch)

            if pr_run and pr_run.get("status") == "running":
                print(f"CI run {_ci_run_url(pr_run['id'])} on branch {branch!r} is running. Waiting.")
                _write_state(None, pending_issue, "pending-ci")
                return 0

            if pr_run and pr_run.get("status") in ("failure", "error"):
                print(f"CI run {_ci_run_url(pr_run['id'])} on branch {branch!r} failed — starting fix agent.")
                prompt = (
                    f"The Codeberg CI for guettli/sharedinbox just failed on branch {branch!r} "
                    f"(PR #{pr_number}). "
                    f"CI run: {_ci_run_url(pr_run['id'])}. "
                    "Fetch the CI logs using the task ci-logs command or the Codeberg API. "
                    "Identify the failure, fix it, commit, and push to the same branch. "
                    "Do NOT push to main, do NOT close the issue, do NOT merge the PR. "
                    "Verify locally with 'task check' before pushing. "
                    "When done, stop."
                )
                session_name = f"ci-fix-pr-{pr_number}"
                pid = _start_agent(prompt, session_name)
                _write_state(pid, pending_issue, "ci-fix", session_name=session_name)
                return 0

            if not pr_run:
                # No CI run yet — might be that CI hasn't triggered yet.
                # Wait up to 15 min before giving up.
                pr_created_at = pr.get("created_at", "")
                try:
                    created = datetime.fromisoformat(pr_created_at.replace("Z", "+00:00"))
                    age_s = (datetime.now(timezone.utc) - created).total_seconds()
                except Exception:
                    age_s = 999999
                if age_s < 900:
                    print(
                        f"PR #{pr_number} has no CI run yet (created {age_s/60:.0f} min ago). Waiting."
                    )
                    _write_state(None, pending_issue, "pending-ci")
                    return 0
                print(
                    f"No CI run for branch {branch!r} after {age_s/60:.0f} min — "
                    "agent may not have pushed. Setting to State/Question."
                )
                _set_labels(pending_issue, add=[LABEL_QUESTION], remove=[LABEL_IN_PROGRESS])
                _comment_issue(
                    pending_issue,
                    f"Agent opened PR #{pr_number} but no CI run appeared on branch `{branch}` "
                    f"after {age_s/60:.0f} min. The agent may not have pushed any commits. "
                    "Please investigate and resume manually.",
                )
                return 0

            # CI passed on the PR branch — squash-merge and close.
            print(f"CI passed on branch {branch!r} — merging PR #{pr_number}.")
            _merge_pr(pr_number)
            _close_issue(pending_issue)
            print(f"Merged PR #{pr_number} and closed {_issue_url(pending_issue)}.")
            return 0

    # ── 3. Global CI check (agent pushed to main, or no pending issue) ────────
    run = _latest_ci_run()

    if run and run.get("status") == "running":
        print(f"CI run {_ci_run_url(run['id'])} is still running. Waiting.")
        if pending_issue:
            _write_state(None, pending_issue, "pending-ci")
        return 0

    if run and run.get("status") in ("failure", "error"):
        print(f"CI run {_ci_run_url(run['id'])} failed — starting fix agent.")
        prompt = (
            "The Codeberg CI for guettli/sharedinbox just failed. "
            f"The CI run ID is {run['id']}. "
            "Fetch the CI logs using the task ci-logs command or the Codeberg API. "
            "Identify the failure, fix it, commit, and push. "
            "Verify locally with 'task check' before pushing. "
            "When done, stop."
        )
        pid = _start_agent(prompt, "ci-fix")
        _write_state(pid, pending_issue, "ci-fix", session_name="ci-fix")
        return 0

    # CI is ok (or no run).
    if pending_issue:
        latest_run_id = run["id"] if run else None
        if ci_run_id_at_start is not None and latest_run_id == ci_run_id_at_start:
            # CI run hasn't changed since the agent was launched → agent pushed nothing
            # (likely crashed or hit a rate limit).
            print(
                f"No new CI run since agent started for {_issue_url(pending_issue)} "
                f"(run id {latest_run_id}) — agent did nothing. Setting to State/Question."
            )
            _set_labels(pending_issue, add=[LABEL_QUESTION], remove=[LABEL_IN_PROGRESS])
            _comment_issue(
                pending_issue,
                "The agent exited without pushing any changes (no new CI run was triggered). "
                "This usually means the agent hit a rate limit or crashed at startup. "
                "The issue has been set to State/Question — please review the agent log and retry.",
            )
            return 0
        _close_issue(pending_issue)
        ci_run_part = f" {_ci_run_url(run['id'])}" if run else ""
        print(f"CI passed{ci_run_part} — closed {_issue_url(pending_issue)}.")
        return 0

    # Find a Ready issue.
    issues = _ready_issues()
    if not issues:
        print("No issues with State/Ready. Nothing to do.")
        return 0

    issue = issues[0]
    issue_number = issue["number"]
    issue_title = issue["title"]
    issue_body = issue.get("body", "")

    print(f"Starting agent for {_issue_url(issue_number)} {issue_title}")

    # Mark InProgress before starting so the next cron tick sees it even if
    # the agent hasn't had time to do so yet.
    _set_labels(
        issue_number,
        add=[LABEL_IN_PROGRESS],
        remove=[LABEL_READY],
    )

    prompt = f"""Work on Codeberg issue #{issue_number} in the guettli/sharedinbox repository.

Issue title: {issue_title}

Issue body:
{issue_body}

Instructions:
- Understand the issue thoroughly before writing any code.
- Implement the required change, following the existing code style.
- Write or update tests as appropriate.
- Run 'task check' locally and fix any failures before committing.
- Commit with a descriptive message referencing the issue number (e.g. "feat: ... (#{issue_number})").
- Create a branch named `issue-{issue_number}-fix`, push your changes there, and open a PR against main:
      git checkout -b issue-{issue_number}-fix
      git push -u origin issue-{issue_number}-fix
      fgj pr create --title "fix: <short description> (#{issue_number})" \\
        --head issue-{issue_number}-fix --base main --repo {REPO}
- Do NOT push to main, do NOT close the issue, and do NOT merge the PR — the loop handles that after CI passes.
- If you hit a blocker you cannot resolve, set the issue label to State/Question
  and stop (do NOT close the issue).
- When the work is pushed and the PR is opened, stop. The loop will merge the PR and close the issue after CI passes.
"""

    session_name = f"issue-{issue_number}"
    pid = _start_agent(prompt, session_name)
    current_run_id = run["id"] if run else None
    _write_state(pid, issue_number, "issue", issue_title, session_name=session_name, ci_run_id=current_run_id)
    return 0


def main() -> int:
    parser = argparse.ArgumentParser(prog="agent_loop")
    sub = parser.add_subparsers(dest="cmd")
    sub.add_parser("list", help="List recent agent sessions")
    args = parser.parse_args()

    if args.cmd == "list":
        return cmd_list()
    return _run_loop()


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