import pytest

from SYS import pipeline as ctx


def test_new_pipeline_state_isolation():
    # Ensure we start with a clean baseline
    ctx.reset()
    ctx.set_last_items(["global"])
    assert ctx.get_last_items() == ["global"]

    with ctx.new_pipeline_state():
        # New state should be fresh
        assert ctx.get_last_items() == []
        ctx.set_last_items(["inner1"])
        assert ctx.get_last_items() == ["inner1"]

        with ctx.new_pipeline_state():
            # Nested fresh state
            assert ctx.get_last_items() == []
            ctx.set_last_items(["inner2"])
            assert ctx.get_last_items() == ["inner2"]

        # After exiting inner, outer new state should still have its values
        assert ctx.get_last_items() == ["inner1"]

    # After all contexts exit, global state remains unchanged
    assert ctx.get_last_items() == ["global"]


def test_display_overlay_priority_and_restore():
    ctx.reset()

    # Set a base last result table and items
    ctx.set_last_result_table("table-a", ["a1", "a2"], subject="sub-a")
    assert ctx.get_last_result_items() == ["a1", "a2"]

    # Overlay should take precedence for selection
    ctx.set_last_result_table_overlay("table-b", ["b1"], subject="sub-b")
    assert ctx.get_last_result_items() == ["b1"]
    assert ctx.get_last_result_subject() == "sub-b"

    # Restoring previous should revert to base
    assert ctx.restore_previous_result_table() is True
    assert ctx.get_last_result_items() == ["a1", "a2"]
    assert ctx.get_last_result_subject() == "sub-a"


def test_pipeline_runner_snapshot_restore():
    from TUI.pipeline_runner import PipelineRunner

    runner = PipelineRunner()
    ctx.reset()

    # Seed state with a few values
    ctx.set_last_result_table("table-x", ["x1", "x2"], subject="sx")
    ctx.set_last_items(["L1"]) 
    ctx.set_current_cmdlet_name("cmd-name")
    ctx.set_pending_pipeline_tail([["stage1"], ["stage2"]], source_command="source")

    snap = runner._snapshot_ctx_state()

    # Mutate state
    ctx.clear_last_result()
    ctx.set_last_items([])
    ctx.set_current_cmdlet_name("other")
    ctx.clear_pending_pipeline_tail()

    # Restore and verify
    runner._restore_ctx_state(snap)
    assert ctx.get_last_result_items() == ["x1", "x2"]
    assert ctx.get_last_items() == ["L1"]
    assert ctx.get_current_cmdlet_name() == "cmd-name"
    assert ctx.get_pending_pipeline_tail() == [["stage1"], ["stage2"]]


def test_preserve_history_no_push():
    ctx.reset()

    ctx.set_last_result_table("t1", ["a"], subject="s1")
    # Push second table
    ctx.set_last_result_table("t2", ["b"], subject="s2")
    state = ctx.get_pipeline_state()
    assert len(state.result_table_history) == 1

    # Preserve history update should NOT push a new history entry
    ctx.set_last_result_table_preserve_history("t2b", ["c"], subject="s2b")
    assert len(state.result_table_history) == 1
    assert ctx.get_last_result_items() == ["c"]


def test_forward_and_restore():
    ctx.reset()

    ctx.set_last_result_table("t1", ["a"], subject="s1")
    ctx.set_last_result_table("t2", ["b"], subject="s2")

    assert ctx.restore_previous_result_table() is True
    assert ctx.get_last_result_items() == ["a"]

    assert ctx.restore_next_result_table() is True
    assert ctx.get_last_result_items() == ["b"]


def test_display_items_priority():
    ctx.reset()

    ctx.set_last_result_table("base", ["x1", "x2"]) 
    ctx.set_last_result_items_only(["d1", "d2"])

    # display items take priority for selection
    assert ctx.get_last_result_items() == ["d1", "d2"]
    # but selectable items should ignore display-only items
    assert ctx.get_last_selectable_result_items() == ["x1", "x2"]