"""Unit tests for the cloning simulator (dee/core/cloning.py)."""
import pytest

from dee.core import cloning as C


# ── Gibson / overlap assembly ───────────────────────────────────────────────
def test_gibson_native_overlaps_circular():
    # three fragments sharing 20-bp overlaps, arranged head-to-tail in a circle.
    o1 = "ACGTACGTACGTACGTACGT"          # A↔B overlap
    o2 = "TTTTGGGGCCCCAAAATTTT"          # B↔C overlap
    o3 = "GGGGCCCCAAAATTTTGGGG"          # C↔A overlap
    A = o3 + "AAAAAAAAAAAA" + o1
    B = o1 + "CCCCCCCCCCCC" + o2
    Cc = o2 + "GGGGGGGGGGGG" + o3
    out = C.gibson([{"name": "A", "seq": A}, {"name": "B", "seq": B}, {"name": "C", "seq": Cc}])
    assert out["ok"] is True
    assert out["topology"] == "circular"
    assert all(j["kind"] == "native" for j in out["junctions"])
    assert out["length"] == len(A) + len(B) + len(Cc) - 60   # minus three 20-bp overlaps


def test_gibson_auto_orders_fragments():
    o1 = "ACGTACGTACGTACGTACGT"
    o2 = "TTTTGGGGCCCCAAAATTTT"
    A = "AAAAAAAA" + o1
    B = o1 + "CCCCCCCC" + o2
    Cc = o2 + "GGGGGGGG"
    out = C.gibson([{"name": "C", "seq": Cc}, {"name": "A", "seq": A}, {"name": "B", "seq": B}],
                   circular=False)
    assert out["ok"] is True
    assert out["order"] == ["A", "B", "C"]
    assert out["length"] == len(A) + len(B) + len(Cc) - 40


def test_gibson_designs_overlaps_and_primers_for_bare_fragments():
    A = "ATGGTGAGCAAGGGCGAGGAGCTGTTCACC"
    B = "GACGAGCTGTACAAGTAACTCGAGCTAGCAT"
    out = C.gibson([{"name": "A", "seq": A}, {"name": "B", "seq": B}], circular=False)
    assert out["ok"] is True
    assert any(j["kind"] == "designed" for j in out["junctions"])
    assert out["length"] == len(A) + len(B)
    prim = {p["fragment"]: p for p in out["primers"]}
    assert prim["B"]["forward_tail"] > 0
    assert prim["B"]["forward"].startswith(A[-25:])


def test_gibson_needs_two_fragments():
    assert C.gibson([{"name": "x", "seq": "ACGT"}])["ok"] is False


# ── Golden Gate ──────────────────────────────────────────────────────────────
def _bsa_part(left_oh, body, right_oh):
    return "GAATT" + "GGTCTC" + "T" + left_oh + body + right_oh + "T" + "GAGACC" + "TTAAG"


def test_excise_part_reads_overhangs():
    p = C._excise_part(_bsa_part("AAAA", "GCTAGCGGGG", "CCCC"), "BsaI")
    assert p["left_oh"] == "AAAA"
    assert p["right_oh"] == "CCCC"
    assert p["inner"] == "AAAA" + "GCTAGCGGGG" + "CCCC"


def test_golden_gate_assembles_circle():
    p1 = _bsa_part("AAAA", "GCTAGCAAAA", "CCCC")
    p2 = _bsa_part("CCCC", "TTGGCCAATT", "AAAA")
    out = C.golden_gate([{"name": "P1", "seq": p1}, {"name": "P2", "seq": p2}], enzyme="BsaI")
    assert out["ok"] is True
    assert out["topology"] == "circular"
    assert out["length"] == (4 + len("GCTAGCAAAA")) + (4 + len("TTGGCCAATT"))
    assert out["order"] == ["P1", "P2"]


def test_golden_gate_rejects_mismatched_overhangs():
    p1 = _bsa_part("AAAA", "GCTAGCAAAA", "CCCC")
    p2 = _bsa_part("GGGG", "TTGGCCAATT", "AAAA")
    out = C.golden_gate([{"name": "P1", "seq": p1}, {"name": "P2", "seq": p2}], enzyme="BsaI")
    assert out["ok"] is False


def test_golden_gate_rejects_non_cassette():
    out = C.golden_gate([{"name": "P1", "seq": "ACGTACGTACGT"}, {"name": "P2", "seq": "TTTTGGGG"}])
    assert out["ok"] is False


# ── restriction cut-and-ligate ──────────────────────────────────────────────
def test_restriction_clone_single_enzyme():
    vector = "AAAACCCC" + "GAATTC" + "TTTTGGGGCCCCAAAA"
    insert = "CC" + "GAATTC" + "ATGCATGCATGCATGC" + "GAATTC" + "GG"
    out = C.restriction_clone(vector, insert, "EcoRI", vector_topology="circular")
    assert out["ok"] is True
    assert out["topology"] == "circular"
    assert "ATGCATGCATGCATGC" in out["assembled"]
    assert out["length"] > len(vector)


def test_restriction_clone_requires_unique_vector_site():
    vector = "GAATTCAAAAGAATTC"
    insert = "GAATTCATGCGAATTC"
    out = C.restriction_clone(vector, insert, "EcoRI", vector_topology="linear")
    assert out["ok"] is False


def test_restriction_clone_requires_flanked_insert():
    vector = "AAAAGAATTCTTTT"
    insert = "ATGCATGCATGC"
    out = C.restriction_clone(vector, insert, "EcoRI")
    assert out["ok"] is False