"""Test pipeline functionality."""
from typing import Dict, List, Optional

import pytest

from langchain.callbacks.manager import CallbackManagerForChainRun
from langchain.chains.base import Chain
from langchain.chains.sequential import SequentialChain, SimpleSequentialChain
from langchain.memory import ConversationBufferMemory
from langchain.memory.simple import SimpleMemory


class FakeChain(Chain):
    """Fake Chain for testing purposes."""

    input_variables: List[str]
    output_variables: List[str]

    @property
    def input_keys(self) -> List[str]:
        """Input keys this chain returns."""
        return self.input_variables

    @property
    def output_keys(self) -> List[str]:
        """Input keys this chain returns."""
        return self.output_variables

    def _call(
        self,
        inputs: Dict[str, str],
        run_manager: Optional[CallbackManagerForChainRun] = None,
    ) -> Dict[str, str]:
        outputs = {}
        for var in self.output_variables:
            variables = [inputs[k] for k in self.input_variables]
            outputs[var] = f"{' '.join(variables)}foo"
        return outputs


def test_sequential_usage_single_inputs() -> None:
    """Test sequential on single input chains."""
    chain_1 = FakeChain(input_variables=["foo"], output_variables=["bar"])
    chain_2 = FakeChain(input_variables=["bar"], output_variables=["baz"])
    chain = SequentialChain(chains=[chain_1, chain_2], input_variables=["foo"])
    output = chain({"foo": "123"})
    expected_output = {"baz": "123foofoo", "foo": "123"}
    assert output == expected_output


def test_sequential_usage_multiple_inputs() -> None:
    """Test sequential on multiple input chains."""
    chain_1 = FakeChain(input_variables=["foo", "test"], output_variables=["bar"])
    chain_2 = FakeChain(input_variables=["bar", "foo"], output_variables=["baz"])
    chain = SequentialChain(chains=[chain_1, chain_2], input_variables=["foo", "test"])
    output = chain({"foo": "123", "test": "456"})
    expected_output = {
        "baz": "123 456foo 123foo",
        "foo": "123",
        "test": "456",
    }
    assert output == expected_output


def test_sequential_usage_memory() -> None:
    """Test sequential usage with memory."""
    memory = SimpleMemory(memories={"zab": "rab"})
    chain_1 = FakeChain(input_variables=["foo"], output_variables=["bar"])
    chain_2 = FakeChain(input_variables=["bar"], output_variables=["baz"])
    chain = SequentialChain(
        memory=memory, chains=[chain_1, chain_2], input_variables=["foo"]
    )
    output = chain({"foo": "123"})
    expected_output = {"baz": "123foofoo", "foo": "123", "zab": "rab"}
    assert output == expected_output
    memory = SimpleMemory(memories={"zab": "rab", "foo": "rab"})
    chain_1 = FakeChain(input_variables=["foo"], output_variables=["bar"])
    chain_2 = FakeChain(input_variables=["bar"], output_variables=["baz"])
    with pytest.raises(ValueError):
        SequentialChain(
            memory=memory, chains=[chain_1, chain_2], input_variables=["foo"]
        )


def test_sequential_internal_chain_use_memory() -> None:
    """Test sequential usage with memory for one of the internal chains."""
    memory = ConversationBufferMemory(memory_key="bla")
    memory.save_context({"input": "yo"}, {"output": "ya"})
    chain_1 = FakeChain(
        input_variables=["foo", "bla"], output_variables=["bar"], memory=memory
    )
    chain_2 = FakeChain(input_variables=["bar"], output_variables=["baz"])
    chain = SequentialChain(chains=[chain_1, chain_2], input_variables=["foo"])
    output = chain({"foo": "123"})
    print("HEYYY OUTPUT", output)
    expected_output = {"foo": "123", "baz": "123 Human: yo\nAI: yafoofoo"}
    assert output == expected_output


def test_sequential_usage_multiple_outputs() -> None:
    """Test sequential usage on multiple output chains."""
    chain_1 = FakeChain(input_variables=["foo"], output_variables=["bar", "test"])
    chain_2 = FakeChain(input_variables=["bar", "foo"], output_variables=["baz"])
    chain = SequentialChain(chains=[chain_1, chain_2], input_variables=["foo"])
    output = chain({"foo": "123"})
    expected_output = {
        "baz": "123foo 123foo",
        "foo": "123",
    }
    assert output == expected_output


def test_sequential_missing_inputs() -> None:
    """Test error is raised when input variables are missing."""
    chain_1 = FakeChain(input_variables=["foo"], output_variables=["bar"])
    chain_2 = FakeChain(input_variables=["bar", "test"], output_variables=["baz"])
    with pytest.raises(ValueError):
        # Also needs "test" as an input
        SequentialChain(chains=[chain_1, chain_2], input_variables=["foo"])


def test_sequential_bad_outputs() -> None:
    """Test error is raised when bad outputs are specified."""
    chain_1 = FakeChain(input_variables=["foo"], output_variables=["bar"])
    chain_2 = FakeChain(input_variables=["bar"], output_variables=["baz"])
    with pytest.raises(ValueError):
        # "test" is not present as an output variable.
        SequentialChain(
            chains=[chain_1, chain_2],
            input_variables=["foo"],
            output_variables=["test"],
        )


def test_sequential_valid_outputs() -> None:
    """Test chain runs when valid outputs are specified."""
    chain_1 = FakeChain(input_variables=["foo"], output_variables=["bar"])
    chain_2 = FakeChain(input_variables=["bar"], output_variables=["baz"])
    chain = SequentialChain(
        chains=[chain_1, chain_2],
        input_variables=["foo"],
        output_variables=["bar", "baz"],
    )
    output = chain({"foo": "123"}, return_only_outputs=True)
    expected_output = {"baz": "123foofoo", "bar": "123foo"}
    assert output == expected_output


def test_sequential_overlapping_inputs() -> None:
    """Test error is raised when input variables are overlapping."""
    chain_1 = FakeChain(input_variables=["foo"], output_variables=["bar", "test"])
    chain_2 = FakeChain(input_variables=["bar"], output_variables=["baz"])
    with pytest.raises(ValueError):
        # "test" is specified as an input, but also is an output of one step
        SequentialChain(chains=[chain_1, chain_2], input_variables=["foo", "test"])


def test_simple_sequential_functionality() -> None:
    """Test simple sequential functionality."""
    chain_1 = FakeChain(input_variables=["foo"], output_variables=["bar"])
    chain_2 = FakeChain(input_variables=["bar"], output_variables=["baz"])
    chain = SimpleSequentialChain(chains=[chain_1, chain_2])
    output = chain({"input": "123"})
    expected_output = {"output": "123foofoo", "input": "123"}
    assert output == expected_output


def test_multi_input_errors() -> None:
    """Test simple sequential errors if multiple input variables are expected."""
    chain_1 = FakeChain(input_variables=["foo"], output_variables=["bar"])
    chain_2 = FakeChain(input_variables=["bar", "foo"], output_variables=["baz"])
    with pytest.raises(ValueError):
        SimpleSequentialChain(chains=[chain_1, chain_2])


def test_multi_output_errors() -> None:
    """Test simple sequential errors if multiple output variables are expected."""
    chain_1 = FakeChain(input_variables=["foo"], output_variables=["bar", "grok"])
    chain_2 = FakeChain(input_variables=["bar"], output_variables=["baz"])
    with pytest.raises(ValueError):
        SimpleSequentialChain(chains=[chain_1, chain_2])
