"""Tests for the rate/load-gated dispatch engine."""

from __future__ import annotations

import uuid as _uuid
from dataclasses import dataclass
from uuid import UUID

import pytest

from claire import events as ev
from claire.db import migrate, open_db
from claire.hlc import HLCGenerator
from claire import scheduler
from claire.web import service


def _setup() -> tuple:
    conn = open_db(":memory:")
    migrate(conn)
    return conn, HLCGenerator("test-machine")


# --- host load / caps ------------------------------------------------------


def _alive_session(conn, gen, host: str, cwd: str) -> UUID:
    sid = _uuid.uuid4()
    ev.append(conn, gen, ev.SessionObserved(session_uuid=sid, host=host, cwd=cwd))
    conn.execute("UPDATE sessions SET liveness = 'alive' WHERE uuid = ?", (str(sid),))
    return sid


def test_host_load_counts_only_alive() -> None:
    conn, gen = _setup()
    _alive_session(conn, gen, "apricot", "/a")
    _alive_session(conn, gen, "apricot", "/b")
    # An observed-but-not-alive session must not count.
    dead = _uuid.uuid4()
    ev.append(conn, gen, ev.SessionObserved(session_uuid=dead, host="apricot", cwd="/c"))
    load = scheduler.host_load(conn)
    assert load.get("apricot") == 2


def test_host_has_capacity() -> None:
    conn, gen = _setup()
    for i in range(3):
        _alive_session(conn, gen, "apricot", f"/p{i}")
    assert scheduler.host_has_capacity(conn, "apricot", per_host_max=3) is False
    assert scheduler.host_has_capacity(conn, "apricot", per_host_max=4) is True
    assert scheduler.host_has_capacity(conn, "plum", per_host_max=3) is True


# --- fake rclaude for dispatch ---------------------------------------------


@dataclass
class _FakeSessionRow:
    host: str
    uuid: UUID
    cwd: str
    mtime_epoch: int
    snippet: str = ""


class _FakeRclaude:
    """spawn() records the call and makes a new session discoverable."""

    def __init__(self, *, spawn_ok: bool = True) -> None:
        self._rows: list[_FakeSessionRow] = []
        self.spawn_calls: list[dict] = []
        self.send_calls: list[dict] = []
        self._spawn_ok = spawn_ok

    def list_sessions(self) -> list[_FakeSessionRow]:
        return list(self._rows)

    def list_tmux(self) -> list:
        return []

    def spawn(
        self,
        *,
        host: str,
        cwd: str,
        mcp_config: str | None = None,
        name: str | None = None,
    ) -> str:
        from claire.rclaude import RclaudeError
        if not self._spawn_ok:
            raise RclaudeError("spawn failed")
        self.spawn_calls.append(
            {"host": host, "cwd": cwd, "mcp_config": mcp_config, "name": name}
        )
        self._rows.append(_FakeSessionRow(
            host=host, uuid=_uuid.uuid4(), cwd=cwd, mtime_epoch=999,
        ))
        return f"claude-tester-{len(self.spawn_calls)}"

    # dispatch_task kicks the new session via `.send()` so Claude flushes its
    # JSONL — record the call as a no-op.
    def send(self, *, text: str, match: str, yes: bool = False, dry_run: bool = False):  # noqa: ARG002
        self.send_calls.append({"text": text, "match": match, "yes": yes})
        return None


# dispatch_task stages a claire `.mcp.json` via a real ssh/subprocess stager.
# Tests must never touch the network — inject a stub instead.
def _no_mcp_stager(host: str) -> str | None:  # noqa: ARG001
    return None


def _project_with_task(conn, gen, *, priority: int = 2):
    proj_id = _uuid.uuid4()
    task_id = _uuid.uuid4()
    ev.append(conn, gen, ev.ProjectCreated(project_id=proj_id, name="p"))
    ev.append(conn, gen, ev.TaskAdded(
        task_id=task_id, project_id=proj_id, title="t", priority=priority,
    ))
    return task_id


def test_dispatch_success() -> None:
    conn, gen = _setup()
    task_id = _project_with_task(conn, gen)
    rcl = _FakeRclaude()
    result = service.dispatch_task(
        conn, gen, task_id=task_id, host="plum", cwd="/work",
        rclaude=rcl, discover_timeout_s=2,
        mcp_stager=lambda _host: "/home/u/.local/share/claire/dispatch-mcp.json",
    )
    assert result.dispatched is True
    assert result.reason == "ok"
    assert result.session_uuid is not None
    assert result.assignment_id is not None
    assert len(rcl.spawn_calls) == 1
    # The staged mcp_config path is wired through to the spawn.
    assert rcl.spawn_calls[0]["mcp_config"] == (
        "/home/u/.local/share/claire/dispatch-mcp.json"
    )
    # Display name follows `<org-or-project>-<task>-<id8>` — the fixture has
    # no org, so the project name ("p") is the prefix, "t" is the task slug,
    # and the suffix is the first 8 chars of the task UUID.
    name = rcl.spawn_calls[0]["name"]
    assert name == f"p-t-{str(task_id)[:8]}", name
    # The kick + /remote-control sends both target the spawned tmux session
    # name (unique), NOT the bare cwd-slug (which a sibling session shares).
    tmux_name = "claude-tester-1"  # _FakeRclaude.spawn's first return value
    assert all(c["match"] == tmux_name for c in rcl.send_calls)
    # A /remote-control registration send occurred with the task-slug name.
    rc_sends = [c for c in rcl.send_calls if c["text"].startswith("/remote-control ")]
    assert len(rc_sends) == 1
    assert rc_sends[0]["text"] == f"/remote-control p-t-{str(task_id)[:8]}"
    # Assignment row exists.
    rows = conn.execute(
        "SELECT COUNT(*) FROM assignments WHERE task_id = ?", (str(task_id),)
    ).fetchone()
    assert rows[0] == 1
    # The dispatched session is addressable: its sessions row carries the
    # spawned tmux_name (a fresh pane has no `--resume`, so the pull loop
    # would never map it — dispatch must record it directly).
    sess = conn.execute(
        "SELECT tmux_name FROM sessions WHERE uuid = ?", (result.session_uuid,)
    ).fetchone()
    assert sess is not None
    assert sess["tmux_name"] == tmux_name


class _FakeRclaudeLocalLabel(_FakeRclaude):
    """Reproduces rclaude's real labeling: it reports the calling machine's
    own sessions as host ``"local"``, NOT the canonical fleet name. The
    base fake echoes the dispatch host, which masked the host-label bug."""

    def spawn(self, *, host, cwd, mcp_config=None, name=None):  # noqa: ARG002
        from claire.rclaude import RclaudeError
        if not self._spawn_ok:
            raise RclaudeError("spawn failed")
        self.spawn_calls.append(
            {"host": host, "cwd": cwd, "mcp_config": mcp_config, "name": name}
        )
        # The on-disk session row is labeled "local" by rclaude regardless of
        # the canonical host we dispatched to.
        self._rows.append(_FakeSessionRow(
            host="local", uuid=_uuid.uuid4(), cwd=cwd, mtime_epoch=999,
        ))
        return f"claude-tester-{len(self.spawn_calls)}"


def test_dispatch_discovers_session_labeled_local(monkeypatch, tmp_path) -> None:
    # Regression: rclaude tags this machine's sessions "local"; dispatching to
    # the machine's canonical name ("plum") must still discover them. The old
    # `r.host == host` filter compared "local" == "plum" and never matched, so
    # discovery timed out and dispatch falsely reported "spawned but not
    # discovered" — even though the JSONL was already on disk.
    monkeypatch.setenv("XDG_CONFIG_HOME", str(tmp_path / "config"))
    cfg_path = tmp_path / "config" / "claire" / "claire.toml"
    cfg_path.parent.mkdir(parents=True, exist_ok=True)
    cfg_path.write_text(
        'machine_id = "m"\nthis_host = "plum"\n'
        '\n[web]\nhost = "127.0.0.1"\nport = 8765\n',
        encoding="utf-8",
    )
    conn, gen = _setup()
    task_id = _project_with_task(conn, gen)
    rcl = _FakeRclaudeLocalLabel()
    result = service.dispatch_task(
        conn, gen, task_id=task_id, host="plum", cwd="/work",
        rclaude=rcl, discover_timeout_s=2, mcp_stager=_no_mcp_stager,
    )
    assert result.dispatched is True, result.reason
    assert result.session_uuid is not None
    assert result.assignment_id is not None
    # The assignment binds the task to the discovered (local-labeled) session.
    rows = conn.execute(
        "SELECT COUNT(*) FROM assignments WHERE task_id = ?", (str(task_id),)
    ).fetchone()
    assert rows[0] == 1


def test_dispatch_ignores_stale_sibling_at_same_cwd(monkeypatch, tmp_path) -> None:
    # Regression: the `pre_uuids` filter had the same "local" vs canonical
    # mismatch, so it was empty — letting discovery latch onto a STALE sibling
    # session already at the cwd instead of the freshly spawned one. With the
    # fix, the pre-existing local-labeled session is excluded and the NEW
    # session (higher mtime) is the one assigned.
    monkeypatch.setenv("XDG_CONFIG_HOME", str(tmp_path / "config"))
    cfg_path = tmp_path / "config" / "claire" / "claire.toml"
    cfg_path.parent.mkdir(parents=True, exist_ok=True)
    cfg_path.write_text(
        'machine_id = "m"\nthis_host = "plum"\n'
        '\n[web]\nhost = "127.0.0.1"\nport = 8765\n',
        encoding="utf-8",
    )
    conn, gen = _setup()
    task_id = _project_with_task(conn, gen)
    rcl = _FakeRclaudeLocalLabel()
    # A stale sibling session already exists at the same cwd, labeled "local",
    # with a HIGHER mtime than the spawn will produce (999) — so the mtime sort
    # alone would wrongly pick it; only excluding it via pre_uuids is correct.
    stale = _uuid.uuid4()
    rcl._rows.append(_FakeSessionRow(
        host="local", uuid=stale, cwd="/work", mtime_epoch=1000,
    ))
    result = service.dispatch_task(
        conn, gen, task_id=task_id, host="plum", cwd="/work",
        rclaude=rcl, discover_timeout_s=2, mcp_stager=_no_mcp_stager,
    )
    assert result.dispatched is True, result.reason
    # The assigned session must be the freshly spawned one, NOT the stale
    # sibling that was present before the spawn.
    assert result.session_uuid != str(stale)


def test_dispatch_refused_host_at_cap(monkeypatch, tmp_path) -> None:
    # Isolate config so the host cap is the default 3, not the dev box's.
    monkeypatch.setenv("XDG_CONFIG_HOME", str(tmp_path / "config"))
    conn, gen = _setup()
    task_id = _project_with_task(conn, gen)
    # Fill plum to the default cap of 3.
    for i in range(3):
        _alive_session(conn, gen, "plum", f"/filler{i}")
    rcl = _FakeRclaude()
    result = service.dispatch_task(
        conn, gen, task_id=task_id, host="plum", cwd="/work",
        rclaude=rcl, discover_timeout_s=2, mcp_stager=_no_mcp_stager,
    )
    assert result.dispatched is False
    assert "capacity" in result.reason
    assert rcl.spawn_calls == []  # never spawned


def test_dispatch_allowed_by_per_host_override(monkeypatch, tmp_path) -> None:
    # plum carries a per-host cap of 5 — filling it to 3 (past the default
    # of 3) must still leave capacity because its override wins.
    monkeypatch.setenv("XDG_CONFIG_HOME", str(tmp_path / "config"))
    cfg_path = tmp_path / "config" / "claire" / "claire.toml"
    cfg_path.parent.mkdir(parents=True, exist_ok=True)
    cfg_path.write_text(
        'machine_id = "m"\n\n[web]\nhost = "127.0.0.1"\nport = 8765\n'
        '\n[limits]\nper_host_max = 3\nper_host = { "plum" = 5 }\n',
        encoding="utf-8",
    )
    conn, gen = _setup()
    task_id = _project_with_task(conn, gen)
    for i in range(3):
        _alive_session(conn, gen, "plum", f"/filler{i}")
    rcl = _FakeRclaude()
    result = service.dispatch_task(
        conn, gen, task_id=task_id, host="plum", cwd="/work",
        rclaude=rcl, discover_timeout_s=2, mcp_stager=_no_mcp_stager,
    )
    assert result.dispatched is True
    assert len(rcl.spawn_calls) == 1


def test_dispatch_refused_over_budget(monkeypatch, tmp_path) -> None:
    # Point config at an isolated file with a tiny daily cap.
    cfg_path = tmp_path / "config" / "claire" / "claire.toml"
    monkeypatch.setenv("XDG_CONFIG_HOME", str(tmp_path / "config"))
    cfg_path.parent.mkdir(parents=True, exist_ok=True)
    cfg_path.write_text(
        'machine_id = "m"\n\n[web]\nhost = "127.0.0.1"\nport = 8765\n'
        "\n[budget]\ndaily_token_cap = 100\nlow_priority_floor = 0.8\n",
        encoding="utf-8",
    )
    conn, gen = _setup()
    task_id = _project_with_task(conn, gen, priority=3)
    # Burn past the cap.
    service.record_usage(conn, gen, source="nl", model="haiku",
                         input_tokens=120, output_tokens=10)
    rcl = _FakeRclaude()
    result = service.dispatch_task(
        conn, gen, task_id=task_id, host="plum", cwd="/work",
        rclaude=rcl, discover_timeout_s=2, mcp_stager=_no_mcp_stager,
    )
    assert result.dispatched is False
    assert "cap" in result.reason.lower()
    assert rcl.spawn_calls == []


def test_dispatch_low_priority_floor(monkeypatch, tmp_path) -> None:
    monkeypatch.setenv("XDG_CONFIG_HOME", str(tmp_path / "config"))
    cfg_path = tmp_path / "config" / "claire" / "claire.toml"
    cfg_path.parent.mkdir(parents=True, exist_ok=True)
    cfg_path.write_text(
        'machine_id = "m"\n\n[web]\nhost = "127.0.0.1"\nport = 8765\n'
        "\n[budget]\ndaily_token_cap = 1000\nlow_priority_floor = 0.5\n",
        encoding="utf-8",
    )
    conn, gen = _setup()
    # 600/1000 used = 60% — past the 50% floor.
    service.record_usage(conn, gen, source="nl", model="haiku",
                         input_tokens=600, output_tokens=0)
    rcl = _FakeRclaude()
    # A P3 task is refused past the floor...
    low = _project_with_task(conn, gen, priority=3)
    r_low = service.dispatch_task(conn, gen, task_id=low, host="plum",
                                  cwd="/w", rclaude=rcl, discover_timeout_s=2,
                                  mcp_stager=_no_mcp_stager)
    assert r_low.dispatched is False
    assert "low-priority" in r_low.reason
    # ...but a P0 task still goes through.
    proj_id = _uuid.uuid4()
    p0 = _uuid.uuid4()
    ev.append(conn, gen, ev.TaskAdded(task_id=p0, project_id=conn.execute(
        "SELECT project_id FROM tasks LIMIT 1").fetchone()[0] and
        UUID(conn.execute("SELECT project_id FROM tasks LIMIT 1").fetchone()[0]),
        title="urgent", priority=0))
    r_p0 = service.dispatch_task(conn, gen, task_id=p0, host="plum",
                                 cwd="/w", rclaude=rcl, discover_timeout_s=2,
                                 mcp_stager=_no_mcp_stager)
    assert r_p0.dispatched is True
    # Degraded path: stager returned None → spawn carried no mcp_config.
    assert rcl.spawn_calls[-1]["mcp_config"] is None