"""Tests for tools/process_registry.py — ProcessRegistry query methods, pruning, checkpoint."""

import json
import time
import pytest
from pathlib import Path
from unittest.mock import MagicMock, patch

from tools.process_registry import (
    ProcessRegistry,
    ProcessSession,
    MAX_OUTPUT_CHARS,
    FINISHED_TTL_SECONDS,
    MAX_PROCESSES,
)


@pytest.fixture()
def registry():
    """Create a fresh ProcessRegistry."""
    return ProcessRegistry()


def _make_session(
    sid="proc_test123",
    command="echo hello",
    task_id="t1",
    exited=False,
    exit_code=None,
    output="",
    started_at=None,
) -> ProcessSession:
    """Helper to create a ProcessSession for testing."""
    s = ProcessSession(
        id=sid,
        command=command,
        task_id=task_id,
        started_at=started_at or time.time(),
        exited=exited,
        exit_code=exit_code,
        output_buffer=output,
    )
    return s


# =========================================================================
# Get / Poll
# =========================================================================

class TestGetAndPoll:
    def test_get_not_found(self, registry):
        assert registry.get("nonexistent") is None

    def test_get_running(self, registry):
        s = _make_session()
        registry._running[s.id] = s
        assert registry.get(s.id) is s

    def test_get_finished(self, registry):
        s = _make_session(exited=True, exit_code=0)
        registry._finished[s.id] = s
        assert registry.get(s.id) is s

    def test_poll_not_found(self, registry):
        result = registry.poll("nonexistent")
        assert result["status"] == "not_found"

    def test_poll_running(self, registry):
        s = _make_session(output="some output here")
        registry._running[s.id] = s
        result = registry.poll(s.id)
        assert result["status"] == "running"
        assert "some output" in result["output_preview"]
        assert result["command"] == "echo hello"

    def test_poll_exited(self, registry):
        s = _make_session(exited=True, exit_code=0, output="done")
        registry._finished[s.id] = s
        result = registry.poll(s.id)
        assert result["status"] == "exited"
        assert result["exit_code"] == 0


# =========================================================================
# Read log
# =========================================================================

class TestReadLog:
    def test_not_found(self, registry):
        result = registry.read_log("nonexistent")
        assert result["status"] == "not_found"

    def test_read_full_log(self, registry):
        lines = "\n".join([f"line {i}" for i in range(50)])
        s = _make_session(output=lines)
        registry._running[s.id] = s
        result = registry.read_log(s.id)
        assert result["total_lines"] == 50

    def test_read_with_limit(self, registry):
        lines = "\n".join([f"line {i}" for i in range(100)])
        s = _make_session(output=lines)
        registry._running[s.id] = s
        result = registry.read_log(s.id, limit=10)
        # Default: last 10 lines
        assert "10 lines" in result["showing"]

    def test_read_with_offset(self, registry):
        lines = "\n".join([f"line {i}" for i in range(100)])
        s = _make_session(output=lines)
        registry._running[s.id] = s
        result = registry.read_log(s.id, offset=10, limit=5)
        assert "5 lines" in result["showing"]


# =========================================================================
# List sessions
# =========================================================================

class TestListSessions:
    def test_empty(self, registry):
        assert registry.list_sessions() == []

    def test_lists_running_and_finished(self, registry):
        s1 = _make_session(sid="proc_1", task_id="t1")
        s2 = _make_session(sid="proc_2", task_id="t1", exited=True, exit_code=0)
        registry._running[s1.id] = s1
        registry._finished[s2.id] = s2
        result = registry.list_sessions()
        assert len(result) == 2

    def test_filter_by_task_id(self, registry):
        s1 = _make_session(sid="proc_1", task_id="t1")
        s2 = _make_session(sid="proc_2", task_id="t2")
        registry._running[s1.id] = s1
        registry._running[s2.id] = s2
        result = registry.list_sessions(task_id="t1")
        assert len(result) == 1
        assert result[0]["session_id"] == "proc_1"

    def test_list_entry_fields(self, registry):
        s = _make_session(output="preview text")
        registry._running[s.id] = s
        entry = registry.list_sessions()[0]
        assert "session_id" in entry
        assert "command" in entry
        assert "status" in entry
        assert "pid" in entry
        assert "output_preview" in entry


# =========================================================================
# Active process queries
# =========================================================================

class TestActiveQueries:
    def test_has_active_processes(self, registry):
        s = _make_session(task_id="t1")
        registry._running[s.id] = s
        assert registry.has_active_processes("t1") is True
        assert registry.has_active_processes("t2") is False

    def test_has_active_for_session(self, registry):
        s = _make_session()
        s.session_key = "gw_session_1"
        registry._running[s.id] = s
        assert registry.has_active_for_session("gw_session_1") is True
        assert registry.has_active_for_session("other") is False

    def test_exited_not_active(self, registry):
        s = _make_session(task_id="t1", exited=True, exit_code=0)
        registry._finished[s.id] = s
        assert registry.has_active_processes("t1") is False


# =========================================================================
# Pruning
# =========================================================================

class TestPruning:
    def test_prune_expired_finished(self, registry):
        old_session = _make_session(
            sid="proc_old",
            exited=True,
            started_at=time.time() - FINISHED_TTL_SECONDS - 100,
        )
        registry._finished[old_session.id] = old_session
        registry._prune_if_needed()
        assert "proc_old" not in registry._finished

    def test_prune_keeps_recent(self, registry):
        recent = _make_session(sid="proc_recent", exited=True)
        registry._finished[recent.id] = recent
        registry._prune_if_needed()
        assert "proc_recent" in registry._finished

    def test_prune_over_max_removes_oldest(self, registry):
        # Fill up to MAX_PROCESSES
        for i in range(MAX_PROCESSES):
            s = _make_session(
                sid=f"proc_{i}",
                exited=True,
                started_at=time.time() - i,  # older as i increases
            )
            registry._finished[s.id] = s

        # Add one more running to trigger prune
        s = _make_session(sid="proc_new")
        registry._running[s.id] = s
        registry._prune_if_needed()

        total = len(registry._running) + len(registry._finished)
        assert total <= MAX_PROCESSES


# =========================================================================
# Checkpoint
# =========================================================================

class TestCheckpoint:
    def test_write_checkpoint(self, registry, tmp_path):
        with patch("tools.process_registry.CHECKPOINT_PATH", tmp_path / "procs.json"):
            s = _make_session()
            registry._running[s.id] = s
            registry._write_checkpoint()

            data = json.loads((tmp_path / "procs.json").read_text())
            assert len(data) == 1
            assert data[0]["session_id"] == s.id

    def test_recover_no_file(self, registry, tmp_path):
        with patch("tools.process_registry.CHECKPOINT_PATH", tmp_path / "missing.json"):
            assert registry.recover_from_checkpoint() == 0

    def test_recover_dead_pid(self, registry, tmp_path):
        checkpoint = tmp_path / "procs.json"
        checkpoint.write_text(json.dumps([{
            "session_id": "proc_dead",
            "command": "sleep 999",
            "pid": 999999999,  # almost certainly not running
            "task_id": "t1",
        }]))
        with patch("tools.process_registry.CHECKPOINT_PATH", checkpoint):
            recovered = registry.recover_from_checkpoint()
            assert recovered == 0


# =========================================================================
# Kill process
# =========================================================================

class TestKillProcess:
    def test_kill_not_found(self, registry):
        result = registry.kill_process("nonexistent")
        assert result["status"] == "not_found"

    def test_kill_already_exited(self, registry):
        s = _make_session(exited=True, exit_code=0)
        registry._finished[s.id] = s
        result = registry.kill_process(s.id)
        assert result["status"] == "already_exited"


# =========================================================================
# Tool handler
# =========================================================================

class TestProcessToolHandler:
    def test_list_action(self):
        from tools.process_registry import _handle_process
        result = json.loads(_handle_process({"action": "list"}))
        assert "processes" in result

    def test_poll_missing_session_id(self):
        from tools.process_registry import _handle_process
        result = json.loads(_handle_process({"action": "poll"}))
        assert "error" in result

    def test_unknown_action(self):
        from tools.process_registry import _handle_process
        result = json.loads(_handle_process({"action": "unknown_action"}))
        assert "error" in result