defmodule Microwaveprop.ValkeyTest do
  # Setup registers a process under the global `Microwaveprop.Valkey.Conn`
  # name and swaps `:microwaveprop, :valkey_adapter` via Application.put_env.
  # Both are global state, so this case must not run concurrently with other
  # tests — otherwise ConnCase setups (which call GridCache.clear/0) see the
  # Mox adapter without expectations and crash unrelated tests.
  use ExUnit.Case, async: false

  import Mox

  alias Microwaveprop.Valkey
  # Register Mox mock as the adapter and fake a Redix connection so
  # configured?() returns true, letting command/pipeline run through the mock.
  alias Microwaveprop.Valkey.Conn
  alias Microwaveprop.Valkey.MockAdapter

  setup do
    prev_url = Application.get_env(:microwaveprop, :valkey_url)
    prev_adapter = Application.get_env(:microwaveprop, :valkey_adapter)

    Application.put_env(:microwaveprop, :valkey_url, "redis://localhost:6379")
    Application.put_env(:microwaveprop, :valkey_adapter, MockAdapter)

    # Start a dummy process registered at the connection name.
    {:ok, pid} = Task.start(fn -> Process.sleep(:infinity) end)
    Process.register(pid, Conn)

    on_exit(fn ->
      Process.unregister(Conn)
      Process.exit(pid, :kill)

      if prev_url,
        do: Application.put_env(:microwaveprop, :valkey_url, prev_url),
        else: Application.delete_env(:microwaveprop, :valkey_url)

      if prev_adapter,
        do: Application.put_env(:microwaveprop, :valkey_adapter, prev_adapter),
        else: Application.delete_env(:microwaveprop, :valkey_adapter)
    end)

    :ok
  end

  describe "child_spec/1" do
    test "returns a valid child spec map" do
      spec = Valkey.child_spec([])

      assert spec.id == Valkey
      assert spec.type == :worker
      assert spec.restart == :permanent
    end
  end

  describe "configured?/0" do
    test "returns true when Redix process is alive" do
      assert Valkey.configured?() == true
    end
  end

  describe "get/1" do
    test "returns :miss when key is nil" do
      expect(MockAdapter, :command, fn _conn, ["GET", "missing"], _opts ->
        {:ok, nil}
      end)

      assert Valkey.get("missing") == :miss
    end

    test "returns decoded term on hit" do
      expect(MockAdapter, :command, fn _conn, ["GET", "key"], _opts ->
        {:ok, :erlang.term_to_binary(%{foo: "bar"})}
      end)

      assert Valkey.get("key") == {:ok, %{foo: "bar"}}
    end

    test "propagates error" do
      expect(MockAdapter, :command, fn _conn, ["GET", "key"], _opts ->
        {:error, :connection_lost}
      end)

      assert Valkey.get("key") == {:error, :connection_lost}
    end
  end

  describe "mget/1" do
    test "empty list returns {:ok, []}" do
      assert Valkey.mget([]) == {:ok, []}
    end

    test "returns decoded values preserving order" do
      expect(MockAdapter, :command, fn _conn, ["MGET", "a", "b"], _opts ->
        {:ok, [nil, :erlang.term_to_binary(42)]}
      end)

      assert Valkey.mget(["a", "b"]) == {:ok, [nil, 42]}
    end

    test "propagates error" do
      expect(MockAdapter, :command, fn _conn, ["MGET", "key"], _opts ->
        {:error, :connection_lost}
      end)

      assert Valkey.mget(["key"]) == {:error, :connection_lost}
    end
  end

  describe "set/3" do
    test "returns :ok on success" do
      expect(MockAdapter, :command, fn _conn, ["SET", "k", _, "EX", "3600"], _opts ->
        {:ok, "OK"}
      end)

      assert Valkey.set("k", "value", 3600) == :ok
    end

    test "propagates error" do
      expect(MockAdapter, :command, fn _conn, ["SET", "k", _, "EX", "3600"], _opts ->
        {:error, :connection_lost}
      end)

      assert Valkey.set("k", "value", 3600) == {:error, :connection_lost}
    end

    test "handles unexpected response" do
      expect(MockAdapter, :command, fn _conn, ["SET", "k", _, "EX", "3600"], _opts ->
        {:ok, "QUEUED"}
      end)

      assert Valkey.set("k", "value", 3600) == {:error, {:ok, "QUEUED"}}
    end
  end

  describe "mset_with_ttl/2" do
    test "empty list returns :ok" do
      assert Valkey.mset_with_ttl([], 3600) == :ok
    end

    test "returns :ok when all SETs succeed" do
      expect(MockAdapter, :pipeline, fn _conn, cmds, _opts ->
        assert length(cmds) == 2
        assert cmds |> hd() |> List.first() == "SET"
        {:ok, ["OK", "OK"]}
      end)

      assert Valkey.mset_with_ttl([{"a", 1}, {"b", 2}], 3600) == :ok
    end

    test "returns {:error, {:partial, _}} when some SETs fail" do
      expect(MockAdapter, :pipeline, fn _conn, _cmds, _opts ->
        {:ok, ["OK", "ERROR"]}
      end)

      assert {:error, {:partial, _}} = Valkey.mset_with_ttl([{"a", 1}, {"b", 2}], 3600)
    end

    test "propagates pipeline error" do
      expect(MockAdapter, :pipeline, fn _conn, _cmds, _opts ->
        {:error, :connection_lost}
      end)

      assert Valkey.mset_with_ttl([{"a", 1}], 3600) == {:error, :connection_lost}
    end
  end

  describe "zadd/3" do
    test "returns :ok on success" do
      expect(MockAdapter, :command, fn _conn, ["ZADD", "zset", "1.5", "mem"], _opts ->
        {:ok, 1}
      end)

      assert Valkey.zadd("zset", 1.5, "mem") == :ok
    end

    test "propagates error" do
      expect(MockAdapter, :command, fn _conn, ["ZADD", "zset", "1.0", "mem"], _opts ->
        {:error, :connection_lost}
      end)

      assert Valkey.zadd("zset", 1.0, "mem") == {:error, :connection_lost}
    end
  end

  describe "zrevrange/3" do
    test "returns members list" do
      expect(MockAdapter, :command, fn _conn, ["ZREVRANGE", "zset", "0", "10"], _opts ->
        {:ok, ["a", "b"]}
      end)

      assert Valkey.zrevrange("zset", 0, 10) == {:ok, ["a", "b"]}
    end

    test "propagates error" do
      expect(MockAdapter, :command, fn _conn, _, _opts ->
        {:error, :connection_lost}
      end)

      assert Valkey.zrevrange("zset", 0, 10) == {:error, :connection_lost}
    end
  end

  describe "zrangebyscore/3" do
    test "returns members list" do
      expect(MockAdapter, :command, fn _conn, ["ZRANGEBYSCORE", "zset", "0", "100"], _opts ->
        {:ok, ["a", "b"]}
      end)

      assert Valkey.zrangebyscore("zset", "0", "100") == {:ok, ["a", "b"]}
    end
  end

  describe "zrem/2" do
    test "empty list returns :ok" do
      assert Valkey.zrem("zset", []) == :ok
    end

    test "removes members" do
      expect(MockAdapter, :command, fn _conn, ["ZREM", "zset", "a", "b"], _opts ->
        {:ok, 2}
      end)

      assert Valkey.zrem("zset", ["a", "b"]) == :ok
    end
  end

  describe "del/1" do
    test "empty list returns :ok" do
      assert Valkey.del([]) == :ok
    end

    test "deletes keys" do
      expect(MockAdapter, :command, fn _conn, ["DEL", "k1", "k2"], _opts ->
        {:ok, 2}
      end)

      assert Valkey.del(["k1", "k2"]) == :ok
    end
  end

  describe "scan_match/1" do
    test "returns all matching keys from single pass" do
      expect(MockAdapter, :command, fn _conn, ["SCAN", "0", "MATCH", "pfx:*", "COUNT", "500"], _opts ->
        {:ok, ["0", ["pfx:a", "pfx:b"]]}
      end)

      assert Valkey.scan_match("pfx:*") == {:ok, ["pfx:a", "pfx:b"]}
    end

    test "follows cursor across multiple passes" do
      MockAdapter
      |> expect(:command, fn _conn, ["SCAN", "0", "MATCH", "pfx:*", "COUNT", "500"], _opts ->
        {:ok, ["3", ["pfx:a"]]}
      end)
      |> expect(:command, fn _conn, ["SCAN", "3", "MATCH", "pfx:*", "COUNT", "500"], _opts ->
        {:ok, ["0", ["pfx:b"]]}
      end)

      assert Valkey.scan_match("pfx:*") == {:ok, ["pfx:a", "pfx:b"]}
    end

    test "propagates error" do
      expect(MockAdapter, :command, fn _conn, _, _opts ->
        {:error, :connection_lost}
      end)

      assert Valkey.scan_match("pfx:*") == {:error, :connection_lost}
    end
  end
end