"""Tests for PE_IPCQ component (ADR-0023 D1, D2, D9, D14).

These tests use a mock setup: PeIpcqComponent is instantiated directly,
its in_ports/out_ports are wired to plain SimPy Stores, and IpcqInitMsg
is delivered via a simple dummy transaction wrapper. PE_DMA is mocked
as a Store that we drain manually.
"""
from __future__ import annotations

from dataclasses import dataclass, field
from typing import Any

import pytest
import simpy

from kernbench.common.ipcq_types import (
    IpcqCreditMetadata,
    IpcqDmaToken,
    IpcqEndpoint,
    IpcqInitEntry,
    IpcqInvalidDirection,
    IpcqMetaArrival,
    IpcqRecvCmd,
    IpcqRequest,
    IpcqSendCmd,
)
from kernbench.components.builtin.pe_ipcq import PeIpcqComponent
from kernbench.runtime_api.kernel import IpcqInitMsg
from kernbench.topology.types import Node


# ── Fakes / fixtures ─────────────────────────────────────────────────


@dataclass
class _FakeTxn:
    request: Any
    done: simpy.Event
    result_data: dict[str, Any] = field(default_factory=dict)


def _make_pe_ipcq(env: simpy.Environment, pe_prefix: str = "sip0.cube0.pe0") -> PeIpcqComponent:
    """Create a PeIpcqComponent with mocked ports.

    Returns the component with:
      - in_ports["host"] for posting IpcqInitMsg / IpcqRequest
      - out_ports["__pe_dma__"] for outgoing IpcqDmaToken (drain manually)
      - The component is started.
    """
    node = Node(
        id=f"{pe_prefix}.pe_ipcq",
        kind="pe_ipcq",
        impl="builtin.pe_ipcq",
        attrs={},
        pos_mm=None,
    )
    comp = PeIpcqComponent(node, ctx=None)
    comp.in_ports["host"] = simpy.Store(env)
    comp.out_ports[f"{pe_prefix}.pe_dma"] = simpy.Store(env)
    comp.start(env)
    return comp


def _install_two_neighbors(env: simpy.Environment, comp: PeIpcqComponent) -> tuple[simpy.Store, simpy.Store]:
    """Install E and W neighbor entries with peer_credit_stores.

    Returns (peer_e_credit_store, peer_w_credit_store) — i.e. the stores
    that the component will put credits into when it receives data.
    """
    peer_e_credit = simpy.Store(env)
    peer_w_credit = simpy.Store(env)

    ep_e = IpcqEndpoint(
        sip=0, cube=0, pe=1,
        buffer_kind="tcm",
        rx_base_pa=0x10_000, rx_base_va=0,
        n_slots=4, slot_size=4096,
    )
    ep_w = IpcqEndpoint(
        sip=0, cube=0, pe=2,
        buffer_kind="tcm",
        rx_base_pa=0x20_000, rx_base_va=0,
        n_slots=4, slot_size=4096,
    )
    init_msg = IpcqInitMsg(
        correlation_id="t", request_id="t",
        target_sips=(0,), target_cubes=(0,), target_pe=0,
        entries=(
            IpcqInitEntry(
                direction="E", peer=ep_e,
                my_rx_base_pa=0x30_000, my_rx_base_va=0,
                n_slots=4, slot_size=4096,
                peer_credit_store=peer_e_credit,
            ),
            IpcqInitEntry(
                direction="W", peer=ep_w,
                my_rx_base_pa=0x40_000, my_rx_base_va=0,
                n_slots=4, slot_size=4096,
                peer_credit_store=peer_w_credit,
            ),
        ),
        backpressure_mode="sleep",
        buffer_kind="tcm",
        credit_size_bytes=16,
    )
    done = env.event()
    comp.in_ports["host"].put(_FakeTxn(request=init_msg, done=done))
    env.run(until=done)
    return peer_e_credit, peer_w_credit


# ── send: forward token to PE_DMA ────────────────────────────────────


def test_send_forwards_token_to_pe_dma():
    env = simpy.Environment()
    comp = _make_pe_ipcq(env)
    _install_two_neighbors(env, comp)
    pe_dma = comp.out_ports["sip0.cube0.pe0.pe_dma"]

    cmd = IpcqSendCmd(
        direction="E", src_addr=0x500, src_space="tcm",
        nbytes=128, shape=(8, 8), dtype="f16", handle_id="s1",
    )
    done = env.event()
    comp.in_ports["host"].put(IpcqRequest(command=cmd, done=done))
    env.run(until=done)

    # Token should be in PE_DMA's mock store
    assert len(pe_dma.items) == 1
    token = pe_dma.items[0]
    assert isinstance(token, IpcqDmaToken)
    assert token.dst_addr == 0x10_000  # peer.rx_base_pa + 0
    assert token.nbytes == 128
    assert token.sender_seq == 0
    assert token.src_direction == "E"


def test_send_advances_my_head_and_slot_addresses():
    env = simpy.Environment()
    comp = _make_pe_ipcq(env)
    _install_two_neighbors(env, comp)
    pe_dma = comp.out_ports["sip0.cube0.pe0.pe_dma"]

    for i in range(3):
        cmd = IpcqSendCmd(
            direction="E", src_addr=0x500 + i,
            src_space="tcm", nbytes=64,
            shape=(8,), dtype="f16", handle_id=f"s{i}",
        )
        done = env.event()
        comp.in_ports["host"].put(IpcqRequest(command=cmd, done=done))
        env.run(until=done)

    tokens = pe_dma.items
    assert [t.sender_seq for t in tokens] == [0, 1, 2]
    # slot addresses: peer.rx_base_pa (0x10_000) + i * slot_size (4096)
    assert [t.dst_addr for t in tokens] == [0x10_000, 0x11_000, 0x12_000]


def test_send_invalid_direction_raises():
    env = simpy.Environment()
    comp = _make_pe_ipcq(env)
    _install_two_neighbors(env, comp)

    cmd = IpcqSendCmd(
        direction="N", src_addr=0x100, src_space="tcm",
        nbytes=64, shape=(8,), dtype="f16", handle_id="s_bad",
    )
    done = env.event()
    comp.in_ports["host"].put(IpcqRequest(command=cmd, done=done))

    with pytest.raises(IpcqInvalidDirection):
        env.run(until=done)


# ── recv: wait for data and return slot address ─────────────────────


def test_recv_waits_until_metadata_arrives():
    env = simpy.Environment()
    comp = _make_pe_ipcq(env)
    _install_two_neighbors(env, comp)

    recv_cmd = IpcqRecvCmd(
        direction="W", shape=(8,), dtype="f16", handle_id="r1",
    )
    recv_req = IpcqRequest(command=recv_cmd, done=env.event())
    comp.in_ports["host"].put(recv_req)

    # Run a bit — recv should not complete yet (no data)
    env.run(until=10)
    assert not recv_req.done.triggered

    # Simulate metadata arrival from peer (W direction = sender pe=2)
    fake_token = IpcqDmaToken(
        src_addr=0, src_space="tcm",
        dst_addr=0x40_000, dst_endpoint=comp._queue_pairs["W"]["peer"],
        nbytes=64, handle_id="x",
        shape=(8,), dtype="f16",
        sender_seq=0,
        src_sip=0, src_cube=0, src_pe=2, src_direction="E",
    )
    comp.in_ports["host"].put(IpcqMetaArrival(token=fake_token))
    env.run(until=recv_req.done)

    assert recv_req.result_data["src_addr"] == 0x40_000  # my_rx_base_pa for W
    assert recv_req.result_data["direction"] == "W"


def test_recv_returns_immediately_if_data_already_present():
    env = simpy.Environment()
    comp = _make_pe_ipcq(env)
    _install_two_neighbors(env, comp)

    # Pre-arrive metadata
    fake_token = IpcqDmaToken(
        src_addr=0, src_space="tcm",
        dst_addr=0x40_000, dst_endpoint=comp._queue_pairs["W"]["peer"],
        nbytes=64, handle_id="x",
        shape=(8,), dtype="f16",
        sender_seq=0,
        src_sip=0, src_cube=0, src_pe=2, src_direction="E",
    )
    comp.in_ports["host"].put(IpcqMetaArrival(token=fake_token))
    env.run(until=5)

    recv_cmd = IpcqRecvCmd(
        direction="W", shape=(8,), dtype="f16", handle_id="r1",
    )
    recv_req = IpcqRequest(command=recv_cmd, done=env.event())
    comp.in_ports["host"].put(recv_req)
    env.run(until=recv_req.done)

    assert recv_req.result_data["src_addr"] == 0x40_000


def test_recv_round_robin_picks_arrived_direction():
    env = simpy.Environment()
    comp = _make_pe_ipcq(env)
    _install_two_neighbors(env, comp)

    # Pre-arrive metadata only on W direction
    fake_token = IpcqDmaToken(
        src_addr=0, src_space="tcm",
        dst_addr=0x40_000, dst_endpoint=comp._queue_pairs["W"]["peer"],
        nbytes=64, handle_id="x",
        shape=(8,), dtype="f16",
        sender_seq=0,
        src_sip=0, src_cube=0, src_pe=2, src_direction="E",
    )
    comp.in_ports["host"].put(IpcqMetaArrival(token=fake_token))
    env.run(until=5)

    # recv() with no direction → round-robin
    recv_cmd = IpcqRecvCmd(
        direction=None, shape=(8,), dtype="f16", handle_id="r_rr",
    )
    recv_req = IpcqRequest(command=recv_cmd, done=env.event())
    comp.in_ports["host"].put(recv_req)
    env.run(until=recv_req.done)

    assert recv_req.result_data["direction"] == "W"


# ── backpressure: send blocks when full ──────────────────────────────


def test_send_blocks_when_peer_slot_full():
    env = simpy.Environment()
    comp = _make_pe_ipcq(env)
    _install_two_neighbors(env, comp)

    # n_slots = 4, so 4 sends should succeed; 5th blocks
    for i in range(4):
        cmd = IpcqSendCmd(
            direction="E", src_addr=0x500, src_space="tcm",
            nbytes=64, shape=(8,), dtype="f16", handle_id=f"s{i}",
        )
        done = env.event()
        comp.in_ports["host"].put(IpcqRequest(command=cmd, done=done))
        env.run(until=done)

    # 5th send: should not complete
    cmd5 = IpcqSendCmd(
        direction="E", src_addr=0x500, src_space="tcm",
        nbytes=64, shape=(8,), dtype="f16", handle_id="s5",
    )
    req5 = IpcqRequest(command=cmd5, done=env.event())
    comp.in_ports["host"].put(req5)
    env.run(until=20)
    assert not req5.done.triggered

    # Send a credit return: peer (E direction, pe=1) consumed slot 0
    credit = IpcqCreditMetadata(
        consumer_seq=1,  # peer consumed up to my_tail=1
        src_sip=0, src_cube=0, src_pe=1, src_direction="W",  # peer's view
    )
    comp.credit_inbox.put(credit)
    env.run(until=req5.done)
    assert req5.done.triggered


# ── Init test ────────────────────────────────────────────────────────


def test_init_installs_neighbors():
    env = simpy.Environment()
    comp = _make_pe_ipcq(env)
    _install_two_neighbors(env, comp)

    assert "E" in comp._queue_pairs
    assert "W" in comp._queue_pairs
    assert comp._queue_pairs["E"]["peer"].pe == 1
    assert comp._queue_pairs["W"]["peer"].pe == 2
    assert comp._queue_pairs["E"]["my_head"] == 0
    assert comp._queue_pairs["E"]["peer_tail_cache"] == 0