from src.cpg.context_extractor import DEFAULT_TOKEN_BUDGET, build_context, render_context


def test_no_context_available_returns_has_context_false():
    ctx = build_context({}, {}, [])
    assert ctx.has_context is False
    assert render_context(ctx) == ""


def test_context_fits_under_budget_keeps_everything():
    ctx = build_context(
        callee_bodies={"foo": "int foo() { return 1; }"},
        callee_signatures={"bar": "int bar(int);"},
        global_decls=["#define MAX 10"],
    )
    assert ctx.has_context is True
    assert ctx.truncated is False
    assert "foo" in ctx.callee_bodies
    assert "bar" in ctx.callee_signatures
    assert ctx.global_decls == ["#define MAX 10"]


def test_truncates_callee_bodies_before_dropping_whole_function():
    big_body = "x " * 10_000  # ~10000 tokens, way over budget
    small_body = "int small() { return 0; }"
    ctx = build_context(
        callee_bodies={"big": big_body, "small": small_body},
        callee_signatures={},
        global_decls=[],
        token_budget=100,
    )
    assert ctx.truncated is True
    assert "big" not in ctx.callee_bodies  # dropped entirely, not mid-body
    assert "small" in ctx.callee_bodies


def test_drops_2hop_signatures_after_bodies_exhaust_budget():
    body = "x " * 90  # exactly 90 whitespace-split tokens
    sig = "int sig(int);"  # 2 tokens
    ctx = build_context(
        callee_bodies={"body_fn": body},
        callee_signatures={"sig_fn": sig},
        global_decls=[],
        token_budget=90,  # leaves 0 remaining after the body, so sig must drop
    )
    assert "body_fn" in ctx.callee_bodies
    assert "sig_fn" not in ctx.callee_signatures
    assert ctx.truncated is True


def test_global_decls_prioritized_over_callee_bodies():
    decl = "typedef struct { int x; } Point;"
    body = "y " * 10_000
    ctx = build_context(
        callee_bodies={"big": body},
        callee_signatures={},
        global_decls=[decl],
        token_budget=50,
    )
    assert ctx.global_decls == [decl]
    assert "big" not in ctx.callee_bodies


def test_default_budget_is_4096():
    assert DEFAULT_TOKEN_BUDGET == 4096


def test_render_context_includes_all_kept_parts():
    ctx = build_context(
        callee_bodies={"foo": "int foo() {}"},
        callee_signatures={"bar": "int bar(int);"},
        global_decls=["#define X 1"],
    )
    rendered = render_context(ctx)
    assert "#define X 1" in rendered
    assert "foo" in rendered
    assert "bar" in rendered