#!/usr/bin/env python3
"""Turn a harness hook payload into a trace event.

Hooks call this, never `wikitool`. A hook fires on every tool call, and every
`wikitool` invocation is counted by the Iteration Budget Gate - wiring telemetry
through the CLI would let the act of observing a session end it. This entry
point imports the telemetry package as a library instead, which costs no budget
and needs no venv: `chemenu.telemetry` is stdlib-only on purpose.

Contract with the harness:

* stdin is the hook's JSON payload; a missing, empty or malformed payload is not
  an error worth failing a tool call over.
* stdout stays empty. Claude Code and Copilot CLI both read a hook's stdout as a
  decision document, so anything printed here could alter what the agent does.
  `--dry-run` is the exception, and it is for humans and tests.
* the exit code is always 0. A hook that exits non-zero can block a tool call,
  and an observer must never do that.

Usage from a hook:

    tools/trace_ingest.py --source copilot-cli --event tool.pre
"""
from __future__ import annotations

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

sys.path.insert(0, str(Path(__file__).resolve().parent))

from chemenu.telemetry import schema  # noqa: E402
from chemenu.telemetry.writer import write_event  # noqa: E402

# Harness event name -> our event name. The keys are what each vendor documents;
# the values are the vocabulary in schema.py. A harness that cannot report an
# event class simply has no row for it - Mistral Vibe has three.
EVENT_MAPS: dict[str, dict[str, str]] = {
    "claude-code": {
        "SessionStart": "session.start",
        "SessionEnd": "session.end",
        "UserPromptSubmit": "prompt.submitted",
        "PreToolUse": "tool.pre",
        "PostToolUse": "tool.post",
        "PostToolUseFailure": "tool.error",
        "SubagentStart": "subagent.start",
        "SubagentStop": "subagent.stop",
        "InstructionsLoaded": "instructions.loaded",
        "PreCompact": "compaction",
        "PostCompact": "compaction",
        "Stop": "turn.end",
    },
    # Copilot CLI serves two payload dialects, chosen by how the event is
    # spelled in the hook config: camelCase names give camelCase fields,
    # PascalCase names give the VS Code / Claude snake_case shape. Both spellings
    # are mapped so a trace stays readable whichever a config uses.
    "copilot-cli": {
        "sessionStart": "session.start",
        "SessionStart": "session.start",
        "sessionEnd": "session.end",
        "SessionEnd": "session.end",
        "userPromptSubmitted": "prompt.submitted",
        "UserPromptSubmit": "prompt.submitted",
        "preToolUse": "tool.pre",
        "PreToolUse": "tool.pre",
        "postToolUse": "tool.post",
        "PostToolUse": "tool.post",
        "postToolUseFailure": "tool.error",
        "PostToolUseFailure": "tool.error",
        "errorOccurred": "session.error",
        "ErrorOccurred": "session.error",
        "subagentStart": "subagent.start",
        "subagentStop": "subagent.stop",
        "SubagentStop": "subagent.stop",
        "preCompact": "compaction",
        "PreCompact": "compaction",
        "agentStop": "turn.end",
        "Stop": "turn.end",
    },
    "mistral-vibe": {
        "pre_tool": "tool.pre",
        "post_tool": "tool.post",
        "post_agent": "turn.end",
    },
}

# Normalised field -> the spellings the three harnesses use, in priority order.
FIELD_ALIASES: dict[str, tuple[str, ...]] = {
    "tool_name": ("tool_name", "toolName", "tool"),
    "tool_call_id": ("tool_call_id", "tool_use_id", "toolCallId", "toolUseId"),
    "tool_input": ("tool_input", "toolArgs", "tool_args", "toolInput"),
    "tool_output": ("tool_output_text", "tool_output", "tool_response", "toolResult"),
    "tool_status": ("tool_status", "status", "toolStatus"),
    "duration_ms": ("duration_ms", "durationMs"),
    "error": ("tool_error", "error", "errorMessage"),
    "error_context": ("error_context", "errorContext"),
    "prompt": ("prompt", "userPrompt", "promptText", "initialPrompt", "initial_prompt"),
    "message": ("last_assistant_message", "assistantMessage", "response", "message"),
    "cwd": ("cwd", "workingDirectory"),
    "transcript_path": ("transcript_path", "transcriptPath"),
    "file_path": ("file_path", "filePath"),
    "agent_type": ("agent_type", "agentType", "subagent_type", "agentName", "agent_name"),
    "parent_session_id": ("parent_session_id", "parentSessionId"),
    "stop_reason": ("stop_reason", "stopReason"),
    "reason": ("reason",),
    "trigger": ("trigger",),
    "source_kind": ("source",),
}

# Values that live one level down. Copilot's postToolUse wraps the text the
# model saw in a result object rather than handing it over flat.
NESTED_ALIASES: dict[str, tuple[tuple[str, str], ...]] = {
    "tool_output": (
        ("toolResult", "textResultForLlm"),
        ("tool_result", "text_result_for_llm"),
    ),
}

SESSION_ALIASES = ("session_id", "sessionId", "session")

# Leftover payload keys worth keeping. Anything else is vendor bookkeeping that
# would only bloat the trace - a trace is scoring material, not an archive of
# the vendor's payload.
EXTRA_SCALAR_TYPES = (str, int, float, bool)


def _first(payload: dict, names: tuple[str, ...]):
    for name in names:
        if name in payload and payload[name] not in (None, ""):
            return payload[name]
    return None


def _as_text(value) -> str:
    if isinstance(value, str):
        return value
    return json.dumps(value, ensure_ascii=False, sort_keys=True)


def _nested(payload: dict, paths: tuple[tuple[str, str], ...]):
    for outer, inner in paths:
        container = payload.get(outer)
        if isinstance(container, dict) and container.get(inner):
            return container[inner]
    return None


def _error_text(value) -> str:
    """`postToolUseFailure` hands over a string, `errorOccurred` an object."""
    if isinstance(value, dict):
        return value.get("message") or _as_text(value)
    return _as_text(value)


def resolve_event(source: str, payload: dict, explicit: str | None) -> str | None:
    """`--event` wins: not every harness names its event inside the payload."""
    if explicit:
        return explicit
    raw = payload.get("hook_event_name") or payload.get("hookEventName")
    if not raw:
        return None
    return EVENT_MAPS.get(source, {}).get(raw)


def normalise(source: str, event: str, payload: dict) -> dict:
    attrs: dict = {"harness_event": payload.get("hook_event_name") or payload.get("hookEventName")}

    for field, aliases in FIELD_ALIASES.items():
        value = _first(payload, aliases)
        if value is None:
            continue
        if field == "error":
            attrs[field] = _error_text(value)
        elif field in ("tool_input", "tool_output"):
            attrs[field] = _as_text(value)
        else:
            attrs[field] = value

    for field, paths in NESTED_ALIASES.items():
        nested = _nested(payload, paths)
        if nested is not None:
            attrs[field] = _as_text(nested)

    known = set(SESSION_ALIASES) | {"hook_event_name", "hookEventName", "timestamp"}
    for aliases in FIELD_ALIASES.values():
        known.update(aliases)
    for paths in NESTED_ALIASES.values():
        known.update(outer for outer, _ in paths)
    extra = {
        key: value
        for key, value in payload.items()
        if key not in known and isinstance(value, EXTRA_SCALAR_TYPES)
    }
    if extra:
        attrs["extra"] = extra

    # A trace has to say what its harness *could* have reported, or a scorer
    # cannot tell "never happened" from "not observable here".
    if event == "session.start":
        attrs["harness"] = source
        attrs["completeness"] = list(schema.HARNESS_CAPABILITIES.get(source, ()))

    return {key: value for key, value in attrs.items() if value is not None}


def build(source: str, payload: dict, explicit_event: str | None, session: str | None):
    event = resolve_event(source, payload, explicit_event)
    if event is None:
        return None, None, None
    session_id = session or _first(payload, SESSION_ALIASES) or os.environ.get(
        "WIKITOOL_SESSION_ID"
    )
    return event, normalise(source, event, payload), session_id


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--source", required=True, choices=sorted(EVENT_MAPS))
    parser.add_argument(
        "--event",
        help="Our event name, e.g. tool.pre. Required for harnesses that do not "
        "name the event in the payload (Copilot CLI).",
    )
    parser.add_argument("--session", help="Override the session id from the payload.")
    parser.add_argument(
        "--dry-run",
        action="store_true",
        help="Print the event instead of appending it. Never use this from a hook: "
        "some harnesses read a hook's stdout as a decision.",
    )
    args = parser.parse_args()

    raw = sys.stdin.read() if not sys.stdin.isatty() else ""
    try:
        payload = json.loads(raw) if raw.strip() else {}
    except json.JSONDecodeError:
        payload = {}
    if not isinstance(payload, dict):
        payload = {}

    event, attrs, session = build(args.source, payload, args.event, args.session)
    if event is None:
        if args.dry_run:
            sys.stderr.write("no event mapping for this payload\n")
            return 1
        return 0

    if args.dry_run:
        record = schema.make_event(
            args.source, event, attrs, session_id=session or "dry-run", seq=1
        )
        errors = schema.validation_errors(record)
        if errors:
            sys.stderr.write("; ".join(errors) + "\n")
            return 1
        sys.stdout.write(json.dumps(record, ensure_ascii=False) + "\n")
        return 0

    write_event(args.source, event, attrs, session=session)
    return 0


if __name__ == "__main__":
    try:
        sys.exit(main())
    except SystemExit:
        raise
    except BaseException:  # noqa: BLE001 - an observer never breaks the observed
        sys.exit(0)