"""
Unit tests for PEV Agent (TDD Approach - Tests Written First)

Pattern: "Plan, Execute, Verify, Refine" - Iterative improvement with verification

Test Coverage:
- 15 unit tests total
- Planning phase: 3 tests (initial plan, plan refinement, plan structure)
- Execution phase: 3 tests (successful execution, with errors, partial success)
- Verification phase: 4 tests (passed, failed, threshold tuning, edge cases)
- Iteration loop: 3 tests (convergence, max iterations, early exit)
- Configuration: 2 tests (defaults, custom values)

Test Structure (TDD):
1. Write ALL tests first (they should fail)
2. Implement minimal code to make tests pass
3. Refactor if needed
4. Verify all existing tests still pass

Expected test execution time: <1 second per test (Tier 1)
"""

import pytest

# Import agent components (will be implemented after tests)
try:
    from kaizen.agents.specialized.pev import PEVAgent, PEVAgentConfig
except ImportError:
    pytest.skip("PEV agent not yet implemented", allow_module_level=True)


# ============================================================================
# PLANNING PHASE TESTS (3 tests)
# ============================================================================


def test_initial_plan_creation():
    """Test initial plan creation from task"""
    config = PEVAgentConfig(
        llm_provider="mock",
        model="mock-model",
        max_iterations=5,
    )
    agent = PEVAgent(config=config)

    task = "Generate Python code to process CSV file"
    result = agent.run(task=task)

    # Verify initial plan created
    assert "plan" in result
    assert isinstance(result["plan"], dict) or isinstance(result["plan"], list)


def test_plan_refinement_based_on_feedback():
    """Test plan refinement when verification fails"""
    config = PEVAgentConfig(
        llm_provider="mock",
        model="mock-model",
        max_iterations=5,
    )
    agent = PEVAgent(config=config)

    task = "Task that requires refinement"
    result = agent.run(task=task)

    # Verify refinement tracking
    assert "refinements" in result
    assert isinstance(result["refinements"], list)


def test_plan_structure_consistency():
    """Test plan structure consistency across iterations"""
    config = PEVAgentConfig(llm_provider="mock", model="mock-model")
    agent = PEVAgent(config=config)

    result = agent.run(task="Test task")

    # Plan structure should be consistent
    assert "plan" in result
    if isinstance(result["plan"], dict):
        assert "steps" in result["plan"] or "actions" in result["plan"]


# ============================================================================
# EXECUTION PHASE TESTS (3 tests)
# ============================================================================


def test_successful_execution():
    """Test successful plan execution"""
    config = PEVAgentConfig(llm_provider="mock", model="mock-model")
    agent = PEVAgent(config=config)

    result = agent.run(task="Simple executable task")

    # Verify execution results
    assert "execution_result" in result
    assert isinstance(result["execution_result"], dict)


def test_execution_with_errors():
    """Test execution with errors (error recovery)"""
    config = PEVAgentConfig(
        llm_provider="mock",
        model="mock-model",
        enable_error_recovery=True,
    )
    agent = PEVAgent(config=config)

    result = agent.run(task="Task that may have errors")

    # Should handle errors and attempt recovery
    assert "execution_result" in result
    # May have error information but should continue


def test_partial_success_execution():
    """Test execution with partial success"""
    config = PEVAgentConfig(llm_provider="mock", model="mock-model")
    agent = PEVAgent(config=config)

    result = agent.run(task="Complex task with steps")

    # Should track partial success
    assert "execution_result" in result
    if "status" in result["execution_result"]:
        assert result["execution_result"]["status"] in [
            "success",
            "partial",
            "failed",
        ]


# ============================================================================
# VERIFICATION PHASE TESTS (4 tests)
# ============================================================================


def test_verification_passed():
    """Test verification when result passes criteria"""
    config = PEVAgentConfig(
        llm_provider="mock",
        model="mock-model",
        verification_strictness="medium",
    )
    agent = PEVAgent(config=config)

    result = agent.run(task="Task with passing criteria")

    # Verify verification status
    assert "verification" in result
    assert isinstance(result["verification"], dict)
    assert "passed" in result["verification"] or "status" in result["verification"]


def test_verification_failed():
    """Test verification when result fails criteria"""
    config = PEVAgentConfig(
        llm_provider="mock",
        model="mock-model",
        verification_strictness="strict",
    )
    agent = PEVAgent(config=config)

    result = agent.run(task="Task with strict criteria")

    # Should detect verification failure
    assert "verification" in result
    if not result["verification"].get("passed"):
        assert (
            "issues" in result["verification"] or "feedback" in result["verification"]
        )


def test_verification_strictness_levels():
    """Test different verification strictness levels"""
    strictness_levels = ["strict", "medium", "lenient"]

    for strictness in strictness_levels:
        config = PEVAgentConfig(
            llm_provider="mock",
            model="mock-model",
            verification_strictness=strictness,
        )
        agent = PEVAgent(config=config)
        result = agent.run(task="Test task")

        # Should have verification result
        assert "verification" in result


def test_verification_edge_cases():
    """Test verification with edge cases (empty result, malformed data)"""
    config = PEVAgentConfig(llm_provider="mock", model="mock-model")
    agent = PEVAgent(config=config)

    # Empty task
    result = agent.run(task="")
    assert "error" in result or "verification" in result

    # Very short task
    result = agent.run(task="a")
    assert "verification" in result or "error" in result


# ============================================================================
# ITERATION LOOP TESTS (3 tests)
# ============================================================================


def test_iteration_convergence():
    """Test iteration loop converges when verification passes"""
    config = PEVAgentConfig(
        llm_provider="mock",
        model="mock-model",
        max_iterations=5,
    )
    agent = PEVAgent(config=config)

    result = agent.run(task="Task that should converge")

    # Should converge before max iterations
    assert "refinements" in result
    # If converged, should have fewer iterations than max
    if result["verification"].get("passed"):
        assert len(result["refinements"]) < config.max_iterations


def test_max_iterations_limit():
    """Test that iteration loop respects max_iterations limit"""
    config = PEVAgentConfig(
        llm_provider="mock",
        model="mock-model",
        max_iterations=3,
    )
    agent = PEVAgent(config=config)

    result = agent.run(task="Task that may not converge")

    # Should not exceed max_iterations
    assert "refinements" in result
    assert len(result["refinements"]) <= 3


def test_early_exit_on_verification_success():
    """Test early exit when verification passes (no unnecessary iterations)"""
    config = PEVAgentConfig(
        llm_provider="mock",
        model="mock-model",
        max_iterations=10,
    )
    agent = PEVAgent(config=config)

    result = agent.run(task="Simple task")

    # Should exit early if verification passes
    assert "verification" in result
    if result["verification"].get("passed"):
        # Should use fewer than max iterations
        assert len(result.get("refinements", [])) < 10


# ============================================================================
# CONFIGURATION TESTS (2 tests)
# ============================================================================


def test_pev_config_defaults():
    """Test PEVAgentConfig default values"""
    config = PEVAgentConfig()

    # Verify default values
    assert config.llm_provider == "openai"
    assert config.model == "gpt-4"
    assert config.temperature == 0.7
    assert config.max_iterations == 5
    assert config.verification_strictness == "medium"
    assert config.enable_error_recovery is True


def test_pev_config_custom_values():
    """Test PEVAgentConfig with custom values"""
    config = PEVAgentConfig(
        llm_provider="anthropic",
        model="claude-3-opus",
        temperature=0.5,
        max_iterations=10,
        verification_strictness="strict",
        enable_error_recovery=False,
    )

    # Verify custom values
    assert config.llm_provider == "anthropic"
    assert config.model == "claude-3-opus"
    assert config.temperature == 0.5
    assert config.max_iterations == 10
    assert config.verification_strictness == "strict"
    assert config.enable_error_recovery is False
