from unittest.mock import patch, MagicMock

from scripts.git_diff import (
    resolve_default_branch, resolve_base_ref, changed_files_with_ranges,
)


_DIFF = """\
diff --git a/src/api.py b/src/api.py
index 1..2 100644
--- a/src/api.py
+++ b/src/api.py
@@ -12 +12,2 @@
-old line
+new line one
+new line two
diff --git a/src/utils/helpers.ts b/src/utils/helpers.ts
index 3..4 100644
--- a/src/utils/helpers.ts
+++ b/src/utils/helpers.ts
@@ -5,0 +6,1 @@
+  added line
"""


def test_resolve_default_branch_uses_symbolic_ref():
    fake = MagicMock(returncode=0, stdout="refs/remotes/origin/main\n", stderr="")
    with patch("subprocess.run", return_value=fake):
        assert resolve_default_branch("/repo") == "main"


def test_resolve_default_branch_falls_back_to_master():
    def _fake(cmd, **kw):
        if "symbolic-ref" in cmd:
            return MagicMock(returncode=1, stdout="", stderr="")
        if "rev-parse" in cmd and "origin/main" in cmd:
            return MagicMock(returncode=1, stdout="", stderr="")
        if "rev-parse" in cmd and "origin/master" in cmd:
            return MagicMock(returncode=0, stdout="abc\n", stderr="")
        return MagicMock(returncode=1, stdout="", stderr="")
    with patch("subprocess.run", side_effect=_fake):
        assert resolve_default_branch("/repo") == "master"


def test_resolve_base_ref_uses_origin_when_available():
    def _fake(cmd, **kw):
        if "fetch" in cmd:
            return MagicMock(returncode=0, stdout="", stderr="")
        if "rev-parse" in cmd and "--verify" in cmd:
            return MagicMock(returncode=0, stdout="def\n", stderr="")
        return MagicMock(returncode=0, stdout="", stderr="")
    with patch("subprocess.run", side_effect=_fake):
        assert resolve_base_ref("/repo", "main") == "origin/main"


def test_resolve_base_ref_falls_back_when_origin_missing():
    def _fake(cmd, **kw):
        if "fetch" in cmd:
            return MagicMock(returncode=1, stdout="", stderr="no remote\n")
        if "rev-parse" in cmd and "--verify" in cmd:
            return MagicMock(returncode=1, stdout="", stderr="")
        return MagicMock(returncode=0, stdout="", stderr="")
    with patch("subprocess.run", side_effect=_fake):
        assert resolve_base_ref("/repo", "main") == "main"


def test_changed_files_with_ranges_parses_unified0_diff():
    fake = MagicMock(returncode=0, stdout=_DIFF, stderr="")
    with patch("subprocess.run", return_value=fake):
        out = changed_files_with_ranges("/repo", "origin/main", "HEAD")
    paths = {p: ranges for p, ranges in out}
    assert "src/api.py" in paths
    assert paths["src/api.py"] == [(12, 13)]
    assert "src/utils/helpers.ts" in paths
    assert paths["src/utils/helpers.ts"] == [(6, 6)]


def test_changed_files_passes_no_ext_diff_flag():
    fake = MagicMock(returncode=0, stdout="", stderr="")
    with patch("subprocess.run", return_value=fake) as p:
        changed_files_with_ranges("/repo", "origin/main", "HEAD")
    args = p.call_args[0][0]
    assert "--no-ext-diff" in args
    assert "--unified=0" in args
    assert "diff.noprefix=false" in " ".join(args)