from __future__ import annotations

import tempfile
import unittest
from pathlib import Path
from unittest.mock import patch

from src.neko_capacity import (
    desired_neko_count_for_youtube_channels,
    ensure_neko_capacity_for_youtube_channels,
    upsert_env_value,
)


class NekoCapacityTests(unittest.TestCase):
    def test_desired_count_keeps_two_instance_floor_and_sixty_four_instance_cap(self) -> None:
        self.assertEqual(desired_neko_count_for_youtube_channels([]), 2)
        self.assertEqual(desired_neko_count_for_youtube_channels([{"id": "lane1"}]), 2)
        self.assertEqual(desired_neko_count_for_youtube_channels([{"id": "lane1"}, {"id": "lane2"}]), 2)
        self.assertEqual(
            desired_neko_count_for_youtube_channels(
                [{"id": "lane1"}, {"id": "lane2"}, {"id": "lane3"}, {"id": "lane4"}]
            ),
            4,
        )
        self.assertEqual(desired_neko_count_for_youtube_channels({"id": f"lane{i}"} for i in range(80)), 64)

    def test_upsert_env_value_preserves_file_and_changes_target_key(self) -> None:
        with tempfile.TemporaryDirectory() as tmp:
            env = Path(tmp) / "config" / "system-stack.env"
            env.parent.mkdir()
            env.write_text("HOSTNAME_ALIAS=live\nNEKO_INSTANCE_COUNT=2\nPORT=8001\n", encoding="utf-8")

            changed = upsert_env_value(env, "NEKO_INSTANCE_COUNT", "3")

            self.assertTrue(changed)
            self.assertEqual(env.read_text(encoding="utf-8"), "HOSTNAME_ALIAS=live\nNEKO_INSTANCE_COUNT=3\nPORT=8001\n")

    def test_ensure_capacity_increases_env_and_restarts_neko_in_background(self) -> None:
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            env = root / "config" / "system-stack.env"
            env.parent.mkdir()
            env.write_text("NEKO_INSTANCE_COUNT=2\n", encoding="utf-8")
            service_ctl = root / "scripts" / "linux" / "service_ctl.sh"
            service_ctl.parent.mkdir(parents=True)
            service_ctl.write_text("#!/usr/bin/env bash\n", encoding="utf-8")

            with patch("src.neko_capacity.subprocess.Popen") as popen:
                result = ensure_neko_capacity_for_youtube_channels(
                    root,
                    [{"id": "lane1"}, {"id": "lane2"}, {"id": "lane3"}],
                )

            self.assertTrue(result["changed"])
            self.assertTrue(result["restarted"])
            self.assertIn("NEKO_INSTANCE_COUNT=3", env.read_text(encoding="utf-8"))
            popen.assert_called_once()
            self.assertEqual(popen.call_args.args[0][-2:], ["neko", "restart"])

    def test_ensure_capacity_keeps_saved_env_when_restart_spawn_fails(self) -> None:
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            env = root / "config" / "system-stack.env"
            env.parent.mkdir()
            env.write_text("NEKO_INSTANCE_COUNT=2\n", encoding="utf-8")
            service_ctl = root / "scripts" / "linux" / "service_ctl.sh"
            service_ctl.parent.mkdir(parents=True)
            service_ctl.write_text("#!/usr/bin/env bash\n", encoding="utf-8")

            with patch("src.neko_capacity.subprocess.Popen", side_effect=OSError("fork failed")):
                result = ensure_neko_capacity_for_youtube_channels(
                    root,
                    [{"id": "lane1"}, {"id": "lane2"}, {"id": "lane3"}],
                )

            self.assertTrue(result["changed"])
            self.assertFalse(result["restarted"])
            self.assertIn("restart_spawn_failed", result["reason"])
            self.assertIn("NEKO_INSTANCE_COUNT=3", env.read_text(encoding="utf-8"))

    def test_ensure_capacity_does_not_downscale_manual_larger_count(self) -> None:
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            env = root / "config" / "system-stack.env"
            env.parent.mkdir()
            env.write_text("NEKO_INSTANCE_COUNT=3\n", encoding="utf-8")

            result = ensure_neko_capacity_for_youtube_channels(root, [{"id": "lane1"}], restart=False)

            self.assertFalse(result["changed"])
            self.assertEqual(env.read_text(encoding="utf-8"), "NEKO_INSTANCE_COUNT=3\n")


if __name__ == "__main__":
    unittest.main()