"""v0.3 PR #6 — Sub-agent session linkage tests.

Covers:
1. `spawn_subagent_session` creates a child row with correct parent_session_id,
   depth = parent.depth + 1, inherited project_key.
2. Depth limit `MAX_SUBAGENT_DEPTH` rejects further spawns.
3. Spawn against ended/missing parent raises human_required errors.
4. `list_subagents` returns direct children in start-order, excludes grandchildren.
5. Persona upsert behaves correctly — same persona hash → same persona_id.
"""

from __future__ import annotations

import uuid
from collections.abc import AsyncIterator
from datetime import UTC, datetime
from pathlib import Path

import pytest

from my_deepagent.config import load_config
from my_deepagent.errors import MyDeepAgentError
from my_deepagent.persistence.db import Database
from my_deepagent.persistence.models import (
    AgentPersonaRow,
    InteractiveSessionRow,
)
from my_deepagent.persona import Persona
from my_deepagent.subagents import (
    MAX_SUBAGENT_DEPTH,
    list_subagents,
    spawn_subagent_session,
)


def _now() -> str:
    return datetime.now(UTC).isoformat(timespec="seconds")


def _make_persona(name: str = "spec-writer") -> Persona:
    return Persona(
        name=name,
        version=1,
        backend="openrouter",
        model="openrouter:deepseek/deepseek-chat",
        provider_origin="CN/DeepSeek",
        capabilities=("spec_write",),
        max_risk_level="medium",
        system_prompt="System prompt — at least ten chars",
        deepagents_backend="state",
    )


@pytest.fixture
async def db_with_root(tmp_path: Path) -> AsyncIterator[tuple[Database, str]]:
    """Database + one root InteractiveSessionRow with depth=0 + project_key='proj1234abcdef00'."""
    db_url = f"sqlite+aiosqlite:///{tmp_path / 'subagent.sqlite3'}"
    db = Database(db_url)
    await db.init_schema()

    persona_id = str(uuid.uuid4())
    root_id = str(uuid.uuid4())

    async with db.session() as s:
        s.add(
            AgentPersonaRow(
                id=persona_id,
                name="default-interactive",
                version=1,
                hash="parent-hash",
                definition={"name": "default-interactive", "version": 1},
                created_at=_now(),
            )
        )
        s.add(
            InteractiveSessionRow(
                id=root_id,
                persona_id=persona_id,
                persona_hash="parent-hash",
                started_at=_now(),
                last_message_at=_now(),
                state="active",
                total_input_tokens=0,
                total_output_tokens=0,
                model="openrouter:deepseek/deepseek-chat",
                project_key="proj1234abcdef00",
                title="root",
                plan_mode=False,
                parent_session_id=None,
                depth=0,
            )
        )
        await s.commit()
    try:
        yield (db, root_id)
    finally:
        await db.dispose()


# ---------------------------------------------------------------------------
# Happy path
# ---------------------------------------------------------------------------


@pytest.mark.asyncio
async def test_spawn_creates_child_with_inherited_project_key(
    db_with_root: tuple[Database, str],
) -> None:
    db, root_id = db_with_root
    persona = _make_persona()
    child_id = await spawn_subagent_session(
        db,
        parent_session_id=uuid.UUID(root_id),
        persona=persona,
        initial_title="planner-1",
    )
    async with db.session() as s:
        child = await s.get(InteractiveSessionRow, str(child_id))
    assert child is not None
    assert child.parent_session_id == root_id
    assert child.depth == 1
    assert child.project_key == "proj1234abcdef00"  # inherited
    assert child.title == "planner-1"
    assert child.state == "active"
    assert child.plan_mode is False
    assert child.persona_hash == persona.compute_hash()


@pytest.mark.asyncio
async def test_spawn_two_children_depth_one_each(
    db_with_root: tuple[Database, str],
) -> None:
    db, root_id = db_with_root
    persona = _make_persona()
    child_a = await spawn_subagent_session(
        db, parent_session_id=uuid.UUID(root_id), persona=persona
    )
    child_b = await spawn_subagent_session(
        db, parent_session_id=uuid.UUID(root_id), persona=persona
    )
    async with db.session() as s:
        a = await s.get(InteractiveSessionRow, str(child_a))
        b = await s.get(InteractiveSessionRow, str(child_b))
    assert a is not None and b is not None
    assert a.depth == b.depth == 1
    assert a.parent_session_id == b.parent_session_id == root_id


# ---------------------------------------------------------------------------
# Depth limit
# ---------------------------------------------------------------------------


@pytest.mark.asyncio
async def test_spawn_rejects_beyond_max_depth(db_with_root: tuple[Database, str]) -> None:
    db, root_id = db_with_root
    persona = _make_persona()
    current = uuid.UUID(root_id)
    # Chain spawns down to MAX_SUBAGENT_DEPTH (root depth=0; spawn produces 1, 2, 3).
    for expected_depth in range(1, MAX_SUBAGENT_DEPTH + 1):
        new_child = await spawn_subagent_session(db, parent_session_id=current, persona=persona)
        async with db.session() as s:
            row = await s.get(InteractiveSessionRow, str(new_child))
        assert row is not None
        assert row.depth == expected_depth
        current = new_child

    # Now `current` has depth=MAX_SUBAGENT_DEPTH (3) → spawn must reject.
    with pytest.raises(MyDeepAgentError) as exc_info:
        await spawn_subagent_session(db, parent_session_id=current, persona=persona)
    assert exc_info.value.code == "subagent_depth_exceeded"


# ---------------------------------------------------------------------------
# Invalid parent
# ---------------------------------------------------------------------------


@pytest.mark.asyncio
async def test_spawn_missing_parent_raises(db_with_root: tuple[Database, str]) -> None:
    db, _root_id = db_with_root
    persona = _make_persona()
    bogus = uuid.uuid4()
    with pytest.raises(MyDeepAgentError) as exc_info:
        await spawn_subagent_session(db, parent_session_id=bogus, persona=persona)
    assert exc_info.value.code == "parent_session_missing"


@pytest.mark.asyncio
async def test_spawn_ended_parent_raises(db_with_root: tuple[Database, str]) -> None:
    db, root_id = db_with_root
    async with db.session() as s:
        row = await s.get(InteractiveSessionRow, root_id)
        assert row is not None
        row.state = "ended"
        await s.commit()
    persona = _make_persona()
    with pytest.raises(MyDeepAgentError) as exc_info:
        await spawn_subagent_session(db, parent_session_id=uuid.UUID(root_id), persona=persona)
    assert exc_info.value.code == "parent_session_ended"


# ---------------------------------------------------------------------------
# list_subagents
# ---------------------------------------------------------------------------


@pytest.mark.asyncio
async def test_list_subagents_returns_direct_children_only(
    db_with_root: tuple[Database, str],
) -> None:
    db, root_id = db_with_root
    persona = _make_persona()

    # root → child_a → grandchild
    child_a = await spawn_subagent_session(
        db, parent_session_id=uuid.UUID(root_id), persona=persona
    )
    child_b = await spawn_subagent_session(
        db, parent_session_id=uuid.UUID(root_id), persona=persona
    )
    grandchild = await spawn_subagent_session(db, parent_session_id=child_a, persona=persona)

    direct = await list_subagents(db, uuid.UUID(root_id))
    ids = [r.id for r in direct]
    assert str(child_a) in ids
    assert str(child_b) in ids
    assert str(grandchild) not in ids  # depth-2 not in direct children
    assert len(direct) == 2


@pytest.mark.asyncio
async def test_list_subagents_no_children_returns_empty(
    db_with_root: tuple[Database, str],
) -> None:
    db, root_id = db_with_root
    direct = await list_subagents(db, uuid.UUID(root_id))
    assert direct == []


# ---------------------------------------------------------------------------
# Persona upsert
# ---------------------------------------------------------------------------


@pytest.mark.asyncio
async def test_spawn_reuses_persona_row_for_same_hash(
    db_with_root: tuple[Database, str],
) -> None:
    db, root_id = db_with_root
    persona = _make_persona("shared-persona")

    child_a = await spawn_subagent_session(
        db, parent_session_id=uuid.UUID(root_id), persona=persona
    )
    child_b = await spawn_subagent_session(
        db, parent_session_id=uuid.UUID(root_id), persona=persona
    )

    async with db.session() as s:
        a = await s.get(InteractiveSessionRow, str(child_a))
        b = await s.get(InteractiveSessionRow, str(child_b))
    assert a is not None and b is not None
    assert a.persona_id == b.persona_id
    assert a.persona_hash == b.persona_hash
    # No duplicate AgentPersonaRow.
    async with db.session() as s:
        cfg = load_config(workspace_root=Path.cwd(), data_dir=Path.cwd() / "data")  # noqa: F841
        from sqlalchemy import select

        rows = (
            (
                await s.execute(
                    select(AgentPersonaRow).where(AgentPersonaRow.hash == persona.compute_hash())
                )
            )
            .scalars()
            .all()
        )
        assert len(rows) == 1