"""Private terminal-only tombstone queries; never reconstruct executable history.

The authenticated edge supplies the original principal/target/request and frozen
payload. A retired target permits only that exact digest, never fresh admission.
Worker receipt reads additionally require the original private adoption proof.
"""
import hmac
import json

from hermes_state_runtime import RuntimeStoreError, _epoch, _json, _row, _secret_digest, _text, admission_fingerprint

RESULT_PREFIX = 'gateway.admission.result.v1.'
ADMISSION_PREFIX = 'gateway.terminal_admission.v1.'
IDENTITY_PREFIX = 'gateway.terminal_identity.v1.'
WORKER_PREFIX = 'gateway.terminal_worker.v1.'


def compact_result(result, *, user_message=None):
    """Retain replay/accounting and current-turn API output, never cumulative history."""
    result = dict(result)
    value = result.get('result')
    if not isinstance(value, dict):
        return result
    value = dict(value)
    # The tool schema list rides every turn result for in-process transcript logging; it is the
    # same session-wide copy each turn (tens of KB, more with MCP) and no stored-result reader uses it.
    value.pop('tools', None)
    messages = value.get('messages')
    if isinstance(messages, list):
        # Agent results include all previous turns. APIs only project this turn's
        # assistant/tool suffix; previous_response_id stores its own history. Compression
        # is the exception: its replacement snapshot is the only immutable record of the
        # rewritten prefix for this turn. A later live transcript may include a successor.
        if not value.get('_compressed') and not value.get('_messages_are_turn_suffix'):
            from agent.turn_context import reanchor_current_turn_user_idx
            anchor = value.get('current_turn_user_idx')
            if not (type(anchor) is int and 0 <= anchor < len(messages)
                    and isinstance(messages[anchor], dict) and messages[anchor].get('role') == 'user'):
                anchor = reanchor_current_turn_user_idx(messages, user_message)
            value['messages'] = messages[anchor + 1:]
            if anchor >= 0 and isinstance(messages[anchor], dict) and messages[anchor].get('api_content'):
                # The user row as the model saw it (memory prefetch, plugin context): a chained
                # Responses turn replays it instead of a row rebuilt from the raw request text.
                value['_turn_user_row'] = {k: messages[anchor][k] for k in ('role', 'content', 'api_content')}
            # Recovery/verification nudges are later user-role rows within this same turn.
            # Consumers must not infer a new boundary from them after the real anchor is gone.
            value['_messages_are_turn_suffix'] = True
            value.pop('current_turn_user_idx', None)
    result['result'] = value
    return result


# Top-level row key only ``encode_result`` writes. The row's top level is built by the gateway
# (``result``/``usage``), never by the agent or a message, so message fields can't collide with it.
_STORED = '_stored'


def encode_result(result):
    """The stored row keeps the reply once. When the turn's closing assistant message carries
    exactly ``final_response``, its ``content`` is stored as null and the row gets
    ``_stored: {v: 1, reply_ref: <that message's index>}``. Retirement drops ``messages`` and
    keeps ``final_response``, so a deleted session's exact retry still has its reply. A result
    that already has ``_stored`` is stored whole with that value escaped as ``{v: 1, raw: ...}``."""
    if not isinstance(result, dict):
        return result
    if _STORED in result:
        return {**result, _STORED: {'v': 1, 'raw': result[_STORED]}}
    value = result.get('result')
    if not isinstance(value, dict) or not isinstance(value.get('messages'), list):
        return result
    reply, messages = value.get('final_response'), list(value['messages'])
    last = next((i for i in range(len(messages) - 1, -1, -1) if isinstance(messages[i], dict)
                 and messages[i].get('role') == 'assistant'), None)
    if not (isinstance(reply, str) and reply and last is not None and messages[last].get('content') == reply):
        return result
    messages[last] = {**messages[last], 'content': None}
    return {**result, 'result': {**value, 'messages': messages}, _STORED: {'v': 1, 'reply_ref': last}}


def load_result(text):
    """Decode a stored result row. Only a row carrying ``encode_result``'s exact envelope is
    decoded (to the dict it encoded, key order included); every other row, including all rows
    written before it, is returned as stored."""
    # Decodes in place: safe only because each call parses its own copy. A cache in front of this
    # must hand out copies, never the decoded dict itself.
    result = json.loads(text)
    if not isinstance(result, dict) or not isinstance(envelope := result.get(_STORED), dict):
        return result
    if envelope.keys() == {'v', 'raw'} and type(envelope['v']) is int and envelope['v'] == 1:
        result[_STORED] = envelope['raw']
        return result
    value, ref = result.get('result'), envelope.get('reply_ref')
    messages = value.get('messages') if isinstance(value, dict) else None
    if not (envelope.keys() == {'v', 'reply_ref'} and type(envelope['v']) is int and envelope['v'] == 1
            and type(ref) is int and isinstance(messages, list) and 0 <= ref < len(messages)
            and isinstance(value.get('final_response'), str) and isinstance(messages[ref], dict)
            and messages[ref].get('role') == 'assistant' and messages[ref].get('content', 0) is None):
        return result
    messages[ref] = {k: value['final_response'] if k == 'content' else v for k, v in messages[ref].items()}
    del result[_STORED]
    return result


def identity_key(principal_id, session_id, request_id):
    return IDENTITY_PREFIX + admission_fingerprint(canonical_target=session_id,
        payload={'principal': principal_id, 'request': request_id})


def terminal_api_admissions(conn, request_id):
    """Retired API admissions that carried *request_id*: a deleted session's tombstones, kept for
    the exact-retry horizon, still spend its Idempotency-Key for every other target."""
    return [json.loads(row[0]) for row in conn.execute(
        "SELECT value FROM state_meta WHERE key GLOB ? "
        "AND json_extract(value, '$.principal_id')='api' AND json_extract(value, '$.request_id')=?",
        (ADMISSION_PREFIX + '*', request_id))]


def terminal_admission(conn, admission_id):
    saved = conn.execute('SELECT value FROM state_meta WHERE key=?',
                         (ADMISSION_PREFIX + admission_id,)).fetchone()
    return json.loads(saved[0]) if saved else None


def retry_terminal_admission(db, *, epoch, principal_id, session_id, request_id, payload, intent='queue'):
    """None means a live target; a retired miss/conflict is a definitive refusal.

    This is a read-only identity lookup, not authorization to attach, restore a
    route, or write. HTTP authentication/grant checks must precede this query.
    """
    for value in (principal_id, session_id, request_id):
        _text(value)
    digest = admission_fingerprint(canonical_target=session_id,
        payload={'input': json.loads(_json(payload)), 'intent': intent})
    with db._read_ctx() as conn:
        _epoch(conn, epoch)
        from hermes_state_mutation_retirement import RETIRED_PREFIX
        if not conn.execute('SELECT 1 FROM state_meta WHERE key=?', (RETIRED_PREFIX + session_id,)).fetchone():
            return None
        saved = conn.execute('SELECT value FROM state_meta WHERE key=?',
                             (identity_key(principal_id, session_id, request_id),)).fetchone()
        if saved is None:
            raise RuntimeStoreError('not_found')
        row = terminal_admission(conn, json.loads(saved[0]))
        if row['payload_digest'] != digest:
            raise RuntimeStoreError('admission_conflict')
        return _row(row)


def terminal_worker_receipt(db, *, execution_id, session_id, generation, sequence,
                            adoption_secret, payload_digest):
    """Exact retired producer evidence; possession never reactivates the worker."""
    proof = _secret_digest(adoption_secret)
    with db._read_ctx() as conn:
        saved = conn.execute('SELECT value FROM state_meta WHERE key=?',
                             (WORKER_PREFIX + execution_id,)).fetchone()
        if saved is None:
            raise RuntimeStoreError('not_found')
        worker = json.loads(saved[0])
        if worker['session_id'] != session_id or not hmac.compare_digest(worker['adoption_digest'], proof):
            raise RuntimeStoreError('permission_denied')
        if type(generation) is not int or generation != worker['generation']:
            raise RuntimeStoreError('stale_generation')
        receipt = next((r for r in worker['receipts'] if r['sequence'] == sequence), None)
        if receipt is None:
            raise RuntimeStoreError('stale_generation')
        if receipt['payload_digest'] != payload_digest:
            raise RuntimeStoreError('admission_conflict')
        if receipt['result_json'] is None:
            raise RuntimeStoreError('stale_generation')
        return json.loads(receipt['result_json'])