"""Human-readable rendering of background-process notification events.

Events come off ``ProcessRegistry.completion_queue`` (completion, watch_match,
watch_disabled, watch_overflow_*, async_delegation) and are turned into the
``[IMPORTANT: ...]`` / ``[ASYNC DELEGATION ...]`` text injected into the agent
conversation by the CLI drain loop, the gateway, and the TUI.
"""

import time
from contextlib import suppress


def _format_age(seconds: float) -> str:
    """Human-friendly elapsed string ('18m', '2h3m', '45s')."""
    try:
        s = int(max(0, seconds))
    except (TypeError, ValueError):
        return "?"
    if s < 60:
        return f"{s}s"
    m, s = divmod(s, 60)
    if m < 60:
        return f"{m}m" + (f"{s}s" if s else "")
    h, m = divmod(m, 60)
    return f"{h}h" + (f"{m}m" if m else "")


def _model_not_found_patterns() -> "list[str]":
    """Model-not-found phrases from ``agent.error_classifier`` (same classification
    the failover path uses, no hand-copied list to drift); a minimal built-in set
    if the import fails so per-task blocks are never hidden."""
    try:
        from agent.error_classifier import _MODEL_NOT_FOUND_PATTERNS

        return list(_MODEL_NOT_FOUND_PATTERNS)
    except Exception:
        return ["is not a valid model", "model not found", "model_not_found"]


def _delegation_config() -> dict:
    """Active delegation config (model/provider/fallbacks); ``{}`` on any error.
    Lazy ``tools.delegate_tool._load_config`` so the renderer sees the dispatcher's
    model/provider without importing the heavy delegation module at import time."""
    try:
        from tools.delegate_tool import _load_config as _cfg

        return _cfg() or {}
    except Exception:
        return {}


def _delegation_model_not_found(results, config) -> bool:
    """True when a result reflects a config-level model_not_found rejection.
    Requires both a model-not-found phrase AND the currently-configured model
    name in the same error/summary text, so a stale task failing on a
    different (removed) model is not mis-attributed to the config."""
    model = str((config or {}).get("model") or "").lower()
    if not model:
        return False
    patterns = _model_not_found_patterns()
    texts = (" ".join(str(x) for x in (r.get("error"), r.get("summary")) if x).lower() for r in results or [])
    return any(model in text and any(p in text for p in patterns) for text in texts)


def _delegation_model_not_found_notice(results) -> "list[str] | None":
    """Config-level model_not_found notice lines, or None (fail-open) — once per batch."""
    config = _delegation_config()
    if not _delegation_model_not_found(results, config):
        return None
    model = config.get("model") or "?"
    provider = config.get("provider") or "configured provider"
    lines = [
        "⚠ SUBAGENT MODEL REJECTED: the configured Subagent Model "
        f'"{model}" was rejected by provider "{provider}" '
        "(HTTP 400: not a valid model ID).",
        "Every task in this batch failed for this reason before doing any work.",
        "Check Settings → Advanced → Subagent Model (or: hermes config get delegation.model).",
    ]
    with suppress(Exception):
        from hermes_cli.fallback_config import get_fallback_chain

        if not get_fallback_chain(config):
            lines.append("No fallback chain is configured, so no failover was attempted.")
    return lines


_TRUNCATED_SUMMARY_NOTE = (
    "[TRUNCATED — subagent hit its iteration cap; the summary below "
    "may be incomplete. Verify before relying on it, or re-dispatch "
    "the unfinished part.]")


def _is_truncated(entry: dict) -> bool:
    return bool(entry.get("truncated") or entry.get("exit_reason") == "max_iterations")


def _header_lines(evt: dict, title: str, intro: str, completed_at: float) -> "list[str]":
    """Shared preamble: title, intro, blank, dispatch time and task-source lines."""
    lines = [title, intro, ""]
    dispatched_at = evt.get("dispatched_at")
    if isinstance(dispatched_at, (int, float)):
        ts = time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(dispatched_at))
        lines.append(f"Dispatched: {ts} ({_format_age(completed_at - dispatched_at)} ago)")
    return lines


def _task_source_lines(evt: dict) -> "list[str]":
    lines = []
    if evt.get("context"):
        lines.append(f"Context you provided: {evt['context']}")
    if evt.get("toolsets"):
        lines.append(f"Toolsets: {', '.join(evt['toolsets'])}")
    return lines


def _role_model(evt: dict) -> str:
    return f"Role: {evt.get('role') or 'leaf'}   Model: {evt.get('model') or '?'}"


def _format_batch_delegation(evt: dict, deleg_id: str, completed_at: float) -> str:
    """Consolidated block for a delegate_task fan-out that finished as one unit."""
    results = evt.get("results") or []
    goals = evt.get("goals") or []
    n = len(results) if results else len(goals)
    total_dur = evt.get("total_duration_seconds", evt.get("duration_seconds", "?"))
    error = evt.get("error")
    lines = _header_lines(
        evt,
        f"[ASYNC DELEGATION BATCH COMPLETE — {deleg_id}]",
        f"A background fan-out of {n} subagent(s) you dispatched earlier "
        "has finished. All ran in parallel and waited on each other; their "
        "consolidated results are below. You may have moved on since "
        "dispatching — act on these or re-dispatch if things have changed.",
        completed_at)
    lines.extend(_task_source_lines(evt))
    lines.append(f"{_role_model(evt)}   Total duration: {total_dur}s")
    if error and not results:
        lines += ["--- ERROR ---", f"The batch did not complete successfully: {error}"]
        return "\n".join(lines)
    # Config-level rejection notice BEFORE the per-task wall — a rejected
    # delegation model fails every task identically and must not stay buried.
    _notice = _delegation_model_not_found_notice(results)
    if _notice:
        lines += ["", *_notice]
    for r in sorted(results, key=lambda x: x.get("task_index", 0)):
        idx = r.get("task_index", 0)
        r_status = r.get("status", "?")
        r_summary = r.get("summary")
        r_error = r.get("error")
        r_goal = goals[idx] if idx < len(goals) else r.get("goal", "")
        r_truncated = _is_truncated(r)
        icon = "⚠" if r_truncated else ("✓" if r_status in ("completed", "success") else "✗")
        header = f"--- {icon} TASK {idx + 1}/{n}" + (f": {r_goal}" if r_goal else "") + f"  (status={r_status}"
        if r.get("api_calls"):
            header += f", api_calls={r['api_calls']}"
        if r.get("duration_seconds") is not None:
            header += f", {r['duration_seconds']}s"
        if r_truncated:
            header += ", TRUNCATED: hit max_iterations — work may be incomplete"
        lines += ["", header + ") ---"]
        if r_status in ("completed", "success") and r_summary:
            if r_truncated:
                lines.append(_TRUNCATED_SUMMARY_NOTE)
            lines.append(r_summary)
        elif r_summary:
            if r_error:
                lines.append(f"({r_status}: {r_error})")
            lines += ["Partial output:", r_summary]
        else:
            lines.append(f"(no summary — status={r_status}" + (f": {r_error}" if r_error else "") + ")")
        if r.get("live_transcript"):
            lines.append(f"Full live transcript (complete tool/assistant trace): {r['live_transcript']}")
    return "\n".join(lines)


def _format_async_delegation(evt: dict) -> str:
    """Format an async-delegation completion into a self-contained re-injection.
    Carries the FULL original task source (goal, context, toolsets, role, model) plus
    dispatch time, status, and the complete result summary: when this re-enters the
    conversation the agent may be deep in unrelated context and must be able to use
    the result OR re-dispatch without remembering why the subagent existed."""
    deleg_id = evt.get("delegation_id", "unknown")
    completed_at = evt.get("completed_at") or time.time()
    if evt.get("is_batch") or isinstance(evt.get("results"), list):
        return _format_batch_delegation(evt, deleg_id, completed_at)
    status = evt.get("status") or "completed"
    summary = evt.get("summary")
    error = evt.get("error")
    truncated = _is_truncated(evt)
    lines = _header_lines(
        evt,
        f"[ASYNC DELEGATION COMPLETE — {deleg_id}]",
        "A background subagent you dispatched earlier has finished. You may "
        "have moved on since dispatching it; the full task source is below so "
        "you can act on the result or re-dispatch if things have changed.",
        completed_at)
    lines.append(f"Original goal: {evt.get('goal', '') or ''}")
    lines.extend(_task_source_lines(evt))
    lines.append(_role_model(evt))
    _notice = _delegation_model_not_found_notice([evt])
    if _notice:
        lines += ["", *_notice]
    _trunc = " [TRUNCATED: hit max_iterations — work may be incomplete]" if truncated else ""
    lines += [
        f"Status: {status}   API calls: {evt.get('api_calls', 0)}   "
        f"Duration: {evt.get('duration_seconds', '?')}s{_trunc}",
        "--- RESULT ---",
    ]
    if status in ("completed", "success") and summary:
        if truncated:
            lines.append(_TRUNCATED_SUMMARY_NOTE)
        lines.append(summary)
    else:
        if status == "interrupted":
            lines.append("The subagent was interrupted before completing" + (f": {error}" if error else "."))
        else:  # error / timeout / failed
            lines.append(
                f"The subagent did not complete successfully (status={status})." + (f"\n{error}" if error else "")
            )
        if summary:
            lines += ["Partial output:", summary]
    return "\n".join(lines)


def _delegation_attribution_line(evt: dict) -> "str | None":
    """One-line provenance for a subagent-owned process event, else None.
    A background process a subagent started outlives the child and is routed to
    the PARENT conversation, which otherwise sees an anonymous raw output wall.
    Judged on ``owner_task_id`` (the raw spawning id) — ``task_id`` is the
    container key and may be collapsed to the session key."""
    task_id = str(evt.get("owner_task_id") or evt.get("task_id") or "")
    if not task_id.startswith("sa-"):
        return None
    info = None
    with suppress(Exception):
        from tools.delegate_tool import get_subagent_attribution

        info = get_subagent_attribution(task_id)
    if not info:
        # Registry entry aged out — still attribute generically, not anonymously.
        return f"Started by subagent {task_id} (delegate_task)."
    goal = str(info.get("goal") or "").strip()
    if len(goal) > 120:
        goal = goal[:117] + "..."
    deleg = info.get("delegation_id")
    line = f"Started by subagent {task_id}" + (f" of delegation {deleg}" if deleg else "") + "."
    if goal:
        line += f' Task: "{goal}"'
    return line


_REASON_STATUS = {
    "lost": "marked lost because the process backend disappeared",
    "failed_start": "failed to start",
}


def _completion_status(evt: dict) -> str:
    reason = evt.get("completion_reason") or "exited"
    if reason == "killed":
        return f"terminated by {evt.get('termination_source') or 'Hermes'}"
    if reason in _REASON_STATUS:
        return _REASON_STATUS[reason]
    return "completed normally" if evt.get("exit_code", "?") == 0 else "exited"


def format_process_notification(evt: dict) -> "str | None":
    """Format a completion_queue event into an ``[IMPORTANT: ...]`` message."""
    evt_type = evt.get("type", "completion")
    _sid = evt.get("session_id", "unknown")
    _cmd = evt.get("command", "unknown")
    _attribution = _delegation_attribution_line(evt)

    # watch_disabled and overflow events carry their own human-readable `message`;
    # otherwise overflow events would fall through to the completion formatter as a
    # phantom "process exited (exit code ?)".
    if evt_type in ("watch_disabled", "watch_overflow_tripped", "watch_overflow_released"):
        return f"[IMPORTANT: {evt.get('message', '')}]"
    if evt_type == "watch_match":
        _sup = evt.get("suppressed", 0)
        text = f"[IMPORTANT: Background process {_sid} matched watch pattern \"{evt.get('pattern', '?')}\".\n"
        if _attribution:
            text += f"{_attribution}\n"
        text += f"Command: {_cmd}\nMatched output:\n{evt.get('output', '')}"
        if _sup:
            text += f"\n({_sup} earlier matches were suppressed by rate limit)"
        return text + "]"
    if evt_type == "async_delegation":
        return _format_async_delegation(evt)

    _exit = evt.get("exit_code", "?")
    _out = evt.get("output", "")
    _signal = ", SIGTERM" if _exit in {-15, 143, "-15", "143"} else ""
    text = f"[IMPORTANT: Background process {_sid} {_completion_status(evt)} (exit code {_exit}{_signal}).\n"
    if _attribution:
        text += f"{_attribution}\n"
        # A subagent-owned process's full output belongs in the child's transcript,
        # not as a raw wall in the parent — trim hard but keep enough tail to
        # recognise failures.
        if isinstance(_out, str) and len(_out) > 600:
            _out = (
                "...(output trimmed — subagent-owned process; see the "
                "delegation's live transcript for full output)\n"
                + _out[-600:])
    text += f"Command: {_cmd}\nOutput:\n{_out}]"
    return text