"""Unit tests for the Plane-2 builders node (design §3.3.2, §7.1 P3).

Covers the two box-side halves of the §3.3.2 trust boundary this leaf owns:
the trust-control-surface denylist scan (boundary #2) and the diff integrity
hash (boundary #3), plus the LangGraph node's clean-vs-park state transitions.

The tests import the committed foundation contracts (``billing``,
``state_store``, ``task_model``) verbatim and assert the leaf builds on them
without redefining them.
"""

from __future__ import annotations

import pytest

from agent_team import billing
from agent_team.billing import BillingMode, ClaudeResult
from agent_team.nodes import builders
from agent_team.nodes.builders import (
    BuildError,
    TrustBoundaryViolation,
    build_candidate_diff,
    builders_node,
    default_diff_builder,
    iter_diff_target_paths,
    scan_trust_control_surface,
)
from agent_team.state_store import compute_content_hash
from agent_team.task_model import Phase, TaskStatus

# --------------------------------------------------------------------------- #
# Diff fixtures
# --------------------------------------------------------------------------- #

CLEAN_DIFF = """diff --git a/src/app.py b/src/app.py
--- a/src/app.py
+++ b/src/app.py
@@ -1,2 +1,2 @@
-old = 1
+new = 2
"""

NEW_FILE_DIFF = """diff --git a/src/util/helpers.py b/src/util/helpers.py
new file mode 100644
--- /dev/null
+++ b/src/util/helpers.py
@@ -0,0 +1 @@
+def f(): ...
"""

WORKFLOW_DIFF = """diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1 +1 @@
-on: push
+on: [push, pull_request_target]
"""


def _scope_plan(diff_builder, scope=("src",), **extra):
    """Build a plan dict whose declared scope is ``scope``."""
    plan = {"title": "t", "scope": list(scope), "phases": ["p1"]}
    plan.update(extra)
    return plan


@pytest.fixture(autouse=True)
def _restore_invoker():
    """Restore the billing invoker after each test (shared module state)."""
    original = billing._invoker
    yield
    billing._invoker = original


# --------------------------------------------------------------------------- #
# Foundation imports are used verbatim (no redefinition)
# --------------------------------------------------------------------------- #


def test_imports_foundation_contracts_verbatim() -> None:
    # The leaf imports, not redefines, the foundation symbols.
    assert builders.compute_content_hash is compute_content_hash
    assert builders.claude_invoke is billing.claude_invoke
    assert builders.Phase is Phase
    assert builders.TaskStatus is TaskStatus


# --------------------------------------------------------------------------- #
# default_diff_builder uses the §3.1 billing seam
# --------------------------------------------------------------------------- #


def test_default_diff_builder_calls_claude_invoke() -> None:
    seen: dict = {}

    def fake(prompt: str, *, mode: BillingMode, **kw):
        seen["prompt"] = prompt
        return ClaudeResult(text=CLEAN_DIFF, mode=mode)

    billing.set_invoker(fake)
    out = default_diff_builder(plan={"title": "x", "scope": ["src"]}, config=None)
    assert out == CLEAN_DIFF
    # The plan title and scope are surfaced into the build prompt.
    assert "x" in seen["prompt"]
    assert "src" in seen["prompt"]


def test_default_diff_builder_fails_loud_when_unwired() -> None:
    # Foundation contract: the seam raises until an invoker is bound.
    billing._invoker = billing._unconfigured_invoker
    with pytest.raises(RuntimeError):
        default_diff_builder(plan={"title": "x"}, config=None)


# --------------------------------------------------------------------------- #
# Diff parsing / canonicalization
# --------------------------------------------------------------------------- #


def test_iter_targets_reads_plus_header() -> None:
    targets = iter_diff_target_paths(CLEAN_DIFF)
    assert [t.path for t in targets] == ["src/app.py"]


def test_iter_targets_ignores_dev_null_source() -> None:
    targets = iter_diff_target_paths(NEW_FILE_DIFF)
    assert [t.path for t in targets] == ["src/util/helpers.py"]


def test_iter_targets_canonicalizes_dot_segments() -> None:
    diff = "+++ b/src/./sub/../app.py\n"
    targets = iter_diff_target_paths(diff)
    assert [t.path for t in targets] == ["src/app.py"]


def test_iter_targets_dedupes() -> None:
    diff = "+++ b/src/app.py\n+++ b/src/app.py\n"
    assert len(iter_diff_target_paths(diff)) == 1


# --------------------------------------------------------------------------- #
# Denylist: each surface (§3.3.2 boundary #2)
# --------------------------------------------------------------------------- #


def test_scan_clean_diff_is_empty() -> None:
    assert scan_trust_control_surface(CLEAN_DIFF, scope=["src"]) == []


def test_scan_flags_github_workflow() -> None:
    v = scan_trust_control_surface(WORKFLOW_DIFF, scope=["src", ".github"])
    assert len(v) == 1
    assert ".github/workflows" in v[0].reason


@pytest.mark.parametrize(
    "path",
    [
        "infra/template.yaml",
        "samconfig.toml".replace("toml", "yaml"),
        "service/serverless.yml",
        "cdk.json",
        "iam/read-policy.json",
        "policies/deploy.policy.yaml",
        "CODEOWNERS",
        ".github/CODEOWNERS",
        ".github/dependabot.yml",
        ".github/settings.yml",
    ],
)
def test_scan_flags_trust_control_surface(path: str) -> None:
    diff = f"+++ b/{path}\n"
    # Declare a wide scope so the only possible failure is the denylist itself.
    v = scan_trust_control_surface(diff, scope=[path.split("/")[0], "."])
    assert v, f"expected {path} to be denied"
    assert v[0].path == path


def test_scan_denylist_beats_scope() -> None:
    # A workflow file inside the declared scope is still denied.
    v = scan_trust_control_surface(WORKFLOW_DIFF, scope=[".github"])
    assert len(v) == 1
    assert "workflow" in v[0].reason


# --------------------------------------------------------------------------- #
# Scope enforcement
# --------------------------------------------------------------------------- #


def test_scan_flags_out_of_scope_path() -> None:
    diff = "+++ b/other/module.py\n"
    v = scan_trust_control_surface(diff, scope=["src"])
    assert len(v) == 1
    assert "declared scope" in v[0].reason


def test_empty_scope_rejects_everything() -> None:
    # An undeclared scope is a hard stop, not a wildcard.
    v = scan_trust_control_surface(CLEAN_DIFF, scope=[])
    assert len(v) == 1
    assert "declared scope" in v[0].reason


def test_scope_prefix_match_is_boundary_safe() -> None:
    # "src" must not accidentally allow "srcfoo/...".
    diff = "+++ b/srcfoo/app.py\n"
    v = scan_trust_control_surface(diff, scope=["src"])
    assert len(v) == 1
    assert "declared scope" in v[0].reason


# --------------------------------------------------------------------------- #
# Renames cannot launder a forbidden destination
# --------------------------------------------------------------------------- #


def test_rename_into_denied_path_is_flagged() -> None:
    diff = (
        "diff --git a/src/app.py b/.github/workflows/evil.yml\n"
        "similarity index 100%\n"
        "rename from src/app.py\n"
        "rename to .github/workflows/evil.yml\n"
    )
    v = scan_trust_control_surface(diff, scope=["src", ".github"])
    assert len(v) == 1
    assert v[0].path == ".github/workflows/evil.yml"
    assert v[0].rename_from == "src/app.py"


def test_rename_into_out_of_scope_is_flagged() -> None:
    diff = "rename from src/app.py\nrename to other/app.py\n"
    v = scan_trust_control_surface(diff, scope=["src"])
    assert len(v) == 1
    assert v[0].path == "other/app.py"
    assert v[0].rename_from == "src/app.py"


# --------------------------------------------------------------------------- #
# Deletes / mode-changes / copies cannot bypass the scan
# (regression: header-only sections carry their path in ``diff --git``, not the
# ``+++ b/`` body line, so a ``+++``-only scan missed all four of these)
# --------------------------------------------------------------------------- #


def test_delete_of_denied_path_is_flagged() -> None:
    diff = (
        "diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml\n"
        "deleted file mode 100644\n"
        "--- a/.github/workflows/ci.yml\n"
        "+++ /dev/null\n"
        "@@ -1 +0,0 @@\n"
        "-on: push\n"
    )
    v = scan_trust_control_surface(diff, scope=["src", ".github"])
    assert len(v) == 1
    assert v[0].path == ".github/workflows/ci.yml"
    assert "workflow" in v[0].reason


def test_mode_change_only_on_denied_path_is_flagged() -> None:
    # A chmod with no +++ line at all — only the diff --git header exists.
    diff = (
        "diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml\n"
        "old mode 100644\n"
        "new mode 100755\n"
    )
    v = scan_trust_control_surface(diff, scope=["src", ".github"])
    assert len(v) == 1
    assert v[0].path == ".github/workflows/ci.yml"
    assert "workflow" in v[0].reason


def test_copy_into_denied_path_is_flagged() -> None:
    # git ``copy to`` (not ``rename to``) must not launder a forbidden dest.
    diff = (
        "diff --git a/src/x.py b/.github/workflows/evil.yml\n"
        "similarity index 100%\n"
        "copy from src/x.py\n"
        "copy to .github/workflows/evil.yml\n"
    )
    v = scan_trust_control_surface(diff, scope=["src", ".github"])
    assert [x.path for x in v] == [".github/workflows/evil.yml"]
    assert v[0].rename_from == "src/x.py"
    assert "workflow" in v[0].reason


def test_out_of_scope_delete_is_flagged() -> None:
    diff = (
        "diff --git a/secret/key.py b/secret/key.py\n"
        "deleted file mode 100644\n"
        "--- a/secret/key.py\n"
        "+++ /dev/null\n"
        "@@ -1 +0,0 @@\n"
        "-KEY = 1\n"
    )
    v = scan_trust_control_surface(diff, scope=["src"])
    assert len(v) == 1
    assert v[0].path == "secret/key.py"
    assert "scope" in v[0].reason


# --------------------------------------------------------------------------- #
# Unsafe paths (absolute / parent-escaping / indirection)
# --------------------------------------------------------------------------- #


@pytest.mark.parametrize(
    "raw",
    [
        "/etc/passwd",
        "../../../etc/passwd",
        "..",
        "src/../../escape.py",
        "c:/windows/system32",  # absolute-ish via backslash normalization below
    ],
)
def test_scan_flags_unsafe_paths(raw: str) -> None:
    diff = f"+++ b/{raw}\n"
    v = scan_trust_control_surface(diff, scope=["src", "."])
    assert v, f"expected {raw} to be flagged"
    assert any("unsafe" in x.reason or "scope" in x.reason for x in v)


def test_backslash_separator_is_normalized() -> None:
    # A Windows separator must not smuggle a denied path past the POSIX matcher.
    diff = "+++ b/.github\\workflows\\ci.yml\n"
    v = scan_trust_control_surface(diff, scope=[".github"])
    assert len(v) == 1
    assert "workflow" in v[0].reason


# --------------------------------------------------------------------------- #
# build_candidate_diff: hashing (§3.3.2 boundary #3) + errors
# --------------------------------------------------------------------------- #


def _stub_builder(diff: str):
    def _b(*, plan, config):
        return diff

    return _b


def test_build_hash_matches_foundation_primitive() -> None:
    plan = _scope_plan(None)
    outcome = build_candidate_diff(plan, builder=_stub_builder(CLEAN_DIFF))
    assert outcome.diff == CLEAN_DIFF
    assert outcome.diff_hash == compute_content_hash(CLEAN_DIFF.encode("utf-8"))
    assert outcome.clean is True


def test_build_clean_outcome_has_no_violations() -> None:
    plan = _scope_plan(None)
    outcome = build_candidate_diff(plan, builder=_stub_builder(NEW_FILE_DIFF))
    assert outcome.violations == []
    assert outcome.clean is True


def test_build_violation_still_hashes() -> None:
    plan = _scope_plan(None, scope=("src", ".github"))
    outcome = build_candidate_diff(plan, builder=_stub_builder(WORKFLOW_DIFF))
    # Hash recorded for provenance even though the diff is rejected.
    assert outcome.diff_hash == compute_content_hash(WORKFLOW_DIFF.encode("utf-8"))
    assert outcome.clean is False


def test_build_rejects_non_mapping_plan() -> None:
    with pytest.raises(BuildError):
        build_candidate_diff(["not", "a", "mapping"], builder=_stub_builder(CLEAN_DIFF))


def test_build_rejects_empty_diff() -> None:
    plan = _scope_plan(None)
    with pytest.raises(BuildError):
        build_candidate_diff(plan, builder=_stub_builder("   \n  "))


def test_build_uses_default_builder_when_none() -> None:
    billing.set_invoker(
        lambda prompt, *, mode, **kw: ClaudeResult(text=CLEAN_DIFF, mode=mode)
    )
    outcome = build_candidate_diff(_scope_plan(None))
    assert outcome.diff == CLEAN_DIFF
    assert outcome.clean is True


# --------------------------------------------------------------------------- #
# builders_node: state transitions
# --------------------------------------------------------------------------- #


def test_node_clean_advances_to_verify() -> None:
    state = {"plan": _scope_plan(None)}
    update = builders_node(state, builder=_stub_builder(CLEAN_DIFF))
    assert update["candidate_diff"] == CLEAN_DIFF
    assert update["diff_hash"] == compute_content_hash(CLEAN_DIFF.encode("utf-8"))
    assert update["current_phase"] == Phase.VERIFY.value
    assert update["status"] == TaskStatus.ACTIVE.value
    assert "park_reason" not in update


def test_node_violation_parks_for_human_review() -> None:
    state = {"plan": _scope_plan(None, scope=("src", ".github"))}
    update = builders_node(state, builder=_stub_builder(WORKFLOW_DIFF))
    # Diff + hash recorded for provenance/ALARM, but parked — never auto-built.
    assert update["candidate_diff"] == WORKFLOW_DIFF
    assert update["current_phase"] == Phase.PARKED.value
    assert update["status"] == TaskStatus.PARKED.value
    assert "cross-review" in update["park_reason"]
    assert "workflow" in update["park_reason"]


def test_node_out_of_scope_parks() -> None:
    diff = "+++ b/other/x.py\n"
    state = {"plan": _scope_plan(None, scope=("src",))}
    update = builders_node(state, builder=_stub_builder(diff))
    assert update["status"] == TaskStatus.PARKED.value
    assert "declared scope" in update["park_reason"]


def test_node_requires_plan() -> None:
    with pytest.raises(BuildError):
        builders_node({}, builder=_stub_builder(CLEAN_DIFF))


def test_node_uses_default_builder_and_config() -> None:
    captured: dict = {}

    def fake(prompt: str, *, mode: BillingMode, **kw):
        captured["mode"] = mode
        return ClaudeResult(text=CLEAN_DIFF, mode=mode)

    billing.set_invoker(fake)
    state = {"plan": _scope_plan(None)}
    update = builders_node(state, config={"billing_mode": "api"})
    assert update["current_phase"] == Phase.VERIFY.value
    # The config-selected billing mode reached the seam.
    assert captured["mode"] is BillingMode.API


def test_violation_dataclass_shape() -> None:
    v = TrustBoundaryViolation(path="a", reason="b", rename_from="c")
    assert (v.path, v.reason, v.rename_from) == ("a", "b", "c")