"""Tests for built-in macro library (Phase 7).

Tests verify:
- dfasm-macros.AC8.1: Built-in macros available without explicit import
- dfasm-macros.AC8.2: User macro with same name shadows built-in
- dfasm-macros.AC8.3: #loop_counted expands to correct counted loop topology
- dfasm-macros.AC8.4: Program using built-in macros assembles and runs in emulator
"""

from pathlib import Path

import simpy
from lark import Lark

from asm import assemble, run_pipeline
from asm.expand import expand
from asm.ir import IRGraph
from asm.lower import lower
from emu import build_topology


def _get_parser():
    """Get the dfasm parser."""
    grammar_path = Path(__file__).parent.parent / "dfasm.lark"
    return Lark(
        grammar_path.read_text(),
        parser="earley",
        propagate_positions=True,
    )


def parse_and_lower(source: str) -> IRGraph:
    """Parse source and lower to IRGraph (before expansion)."""
    parser = _get_parser()
    tree = parser.parse(source)
    return lower(tree)


def parse_lower_expand(source: str) -> IRGraph:
    """Parse, lower, and expand WITHOUT built-in macros."""
    graph = parse_and_lower(source)
    return expand(graph)


def run_program_direct(source: str, until: int = 1000) -> dict:
    """Assemble source in direct mode, run through emulator.

    Args:
        source: dfasm source code as a string
        until: Simulation timeout in time units (default: 1000)

    Returns:
        Dict mapping PE ID to list of output tokens from that PE
    """
    result = assemble(source)
    env = simpy.Environment()
    sys = build_topology(env, result.pe_configs, result.sm_configs)

    # Inject setup tokens first (frame/IRAM initialization)
    for setup in result.setup_tokens:
        sys.inject(setup)

    # Then inject seed tokens
    for seed in result.seed_tokens:
        sys.inject(seed)

    env.run(until=until)

    # Collect output from each PE's output_log
    outputs = {}
    for pe_id, pe in sys.pes.items():
        outputs[pe_id] = list(pe.output_log)

    return outputs


class TestAC81_BuiltinAvailable:
    """AC8.1: Built-in macros available without explicit import."""

    def test_builtins_loaded_from_constant(self):
        """Verify that built-in macros are available as constant."""
        from asm.builtins import _BUILTIN_LINE_COUNT, BUILTIN_MACROS

        assert len(BUILTIN_MACROS) > 0
        assert _BUILTIN_LINE_COUNT > 0

        assert "#loop_counted" in BUILTIN_MACROS
        assert "#permit_inject" in BUILTIN_MACROS
        assert "#reduce_2 op" in BUILTIN_MACROS

    def test_builtins_prepended_to_pipeline(self):
        """Verify that built-in macros are prepended in run_pipeline."""
        source = """
        @system pe=1, sm=0
        &c <| const, 42
        """
        graph = run_pipeline(source)
        assert graph is not None
        assert len(graph.errors) == 0

    def test_builtin_line_offset_set(self):
        """Verify that builtin_line_offset is set on returned graph."""
        source = """
        @system pe=1, sm=0
        &c <| const, 42
        """
        graph = run_pipeline(source)
        assert graph.builtin_line_offset > 0, "builtin_line_offset should be set"

    def test_builtin_macro_invocation_expands(self):
        """Invoking a built-in macro through pipeline produces expanded nodes."""
        source = """
        @system pe=1, sm=0
        &source <| pass
        &sink <| pass
        #permit_inject &source |> &sink
        """
        graph = run_pipeline(source)
        assert len(graph.errors) == 0

        node_names = list(graph.nodes.keys())
        has_p = any("&p" in n and "permit_inject" in n for n in node_names)
        assert has_p, f"Expected &p node from #permit_inject expansion in {node_names}"

        p_node = next(
            n
            for n in graph.nodes.values()
            if "&p" in n.name and "permit_inject" in n.name
        )
        assert p_node.const == 1, "permit_inject &p should have const=1"


class TestAC82_UserMacroShadows:
    """AC8.2: User macro with same name shadows built-in."""

    def test_user_defined_macro_shadows_builtin(self):
        """User-defined macro with same name shadows built-in.

        Verifies that when a user defines #permit_inject with custom body,
        their definition is used instead of the built-in version.
        """
        source = """
        @system pe=1, sm=0

        ; User defines #permit_inject with a custom body
        #permit_inject *targets |> {
            &custom_node <| const, 99
        }

        ; Invoke the user-defined macro
        &sink <| pass
        #permit_inject &sink
        """
        graph = run_pipeline(source)

        node_names = list(graph.nodes.keys())
        has_custom_node = any("&custom_node" in n for n in node_names)

        assert has_custom_node, (
            f"Expected &custom_node from user macro shadowing built-in in {node_names}"
        )

        custom_node = next(n for n in graph.nodes.values() if "&custom_node" in n.name)
        assert custom_node.const == 99, "User's shadowing macro should use const=99"

    def test_builtin_available_when_not_shadowed(self):
        """Built-in macro is used when user doesn't define it."""
        source = """
        @system pe=1, sm=0
        &sink <| pass
        #reduce_2 add |> &sink
        """
        graph = run_pipeline(source)
        assert graph is not None
        assert len(graph.errors) == 0

        node_names = list(graph.nodes.keys())
        has_r = any("&r" in n for n in node_names)
        assert has_r, f"Expected &r node from #reduce_2 expansion in {node_names}"


class TestAC83_LoopCountedTopology:
    """AC8.3: #loop_counted macro defines correct loop topology."""

    def test_loop_counted_invoked_expands_with_required_opcodes(self):
        """#loop_counted invoked through pipeline expands with correct opcodes.

        Verifies expanded graph contains nodes with:
        - add (counter arithmetic)
        - brgt (greater-than comparison)
        - inc (increment)
        """
        source = """
        @system pe=1, sm=0
        &init <| const, 0
        &limit <| const, 10
        &body <| pass
        &exit <| pass
        #loop_counted &init, &limit |> body=&body, exit=&exit
        """
        graph = run_pipeline(source)
        assert len(graph.errors) == 0

        from cm_inst import ArithOp, RoutingOp

        opcode_names = set()
        for node in graph.nodes.values():
            if node.opcode is not None:
                if isinstance(node.opcode, ArithOp):
                    opcode_names.add(node.opcode.name.lower())
                elif isinstance(node.opcode, RoutingOp):
                    opcode_names.add(node.opcode.name.lower())

        assert "add" in opcode_names, f"Expected 'add' opcode, got: {opcode_names}"
        assert "brgt" in opcode_names, f"Expected 'brgt' opcode, got: {opcode_names}"
        assert "inc" in opcode_names, f"Expected 'inc' opcode, got: {opcode_names}"

    def test_loop_counted_invoked_creates_feedback_topology(self):
        """#loop_counted invoked creates feedback arc from increment to counter.

        Verifies the graph has correct loop feedback topology:
        counter -> compare, compare -> inc, inc -> counter (feedback).
        """
        source = """
        @system pe=1, sm=0
        &init <| const, 0
        &limit <| const, 10
        &body <| pass
        &exit <| pass
        #loop_counted &init, &limit |> body=&body, exit=&exit
        """
        graph = run_pipeline(source)

        from cm_inst import ArithOp

        add_nodes = [
            n
            for n, node in graph.nodes.items()
            if isinstance(node.opcode, ArithOp) and node.opcode == ArithOp.ADD
        ]
        inc_nodes = [
            n
            for n, node in graph.nodes.items()
            if isinstance(node.opcode, ArithOp) and node.opcode == ArithOp.INC
        ]

        assert len(add_nodes) >= 1, (
            f"Expected at least 1 'add' node, got {len(add_nodes)}"
        )
        assert len(inc_nodes) >= 1, (
            f"Expected at least 1 'inc' node, got {len(inc_nodes)}"
        )

        edge_pairs = [(edge.source, edge.dest, edge.port) for edge in graph.edges]

        add_node = add_nodes[0]
        inc_node = inc_nodes[0]
        has_feedback = any(
            src == inc_node
            and dst == add_node
            and (port.name == "R" if hasattr(port, "name") else port == "R")
            for src, dst, port in edge_pairs
        )
        assert has_feedback, (
            f"Expected feedback edge from inc to counter, edges: {edge_pairs}"
        )


class TestAC84_EndToEnd:
    """AC8.4: Program using built-in macros assembles and runs in emulator."""

    def test_builtin_reduce_2_invoked_assembles(self):
        """#reduce_2 add invocation assembles through the full pipeline."""
        source = """
        @system pe=1, sm=0
        &out <| pass
        #reduce_2 add |> &out
        """
        result = assemble(source)
        assert result is not None, "assemble() should succeed"
        assert len(result.pe_configs) > 0, "Should have PE configs"

    def test_builtin_reduce_2_runs_in_emulator(self):
        """#reduce_2 add runs through emulator without error."""
        source = """
        @system pe=1, sm=0
        &out <| pass
        #reduce_2 add |> &out
        """
        outputs = run_program_direct(source, until=500)
        assert 0 in outputs, "PE 0 should exist in outputs"

    def test_builtin_reduce_2_produces_output_when_wired(self):
        """#reduce_2 add produces correct sum when inputs and output are wired via @ret."""
        source = """
        @system pe=1, sm=0
        &a <| const, 3
        &b <| const, 4
        &out <| pass
        #reduce_2 add |> &out
        &a |> #reduce_2_0.&r:L
        &b |> #reduce_2_0.&r:R
        """
        outputs = run_program_direct(source, until=500)
        all_values = []
        for pe_outputs in outputs.values():
            all_values.extend([t.data for t in pe_outputs if hasattr(t, "data")])
        assert 7 in all_values, f"Expected 3+4=7 in outputs, got {all_values}"

    def test_builtin_permit_inject_assembles_and_runs(self):
        """#permit_inject assembles and expands to const nodes."""
        source = """
        @system pe=1, sm=0
        &source <| pass
        &sink <| pass
        #permit_inject &source |> &sink
        """
        result = assemble(source)
        assert result is not None
        assert len(result.pe_configs) > 0

        outputs = run_program_direct(source, until=500)
        assert 0 in outputs, "PE 0 should exist in outputs"

    def test_builtin_reduce_3_assembles(self):
        """#reduce_3 add invocation assembles through the full pipeline."""
        source = """
        @system pe=1, sm=0
        &out <| pass
        #reduce_3 add |> &out
        """
        result = assemble(source)
        assert result is not None, "assemble() should succeed"
        assert len(result.pe_configs) > 0, "Should have PE configs"

    def test_builtin_reduce_3_runs_in_emulator(self):
        """#reduce_3 add runs through emulator without error."""
        source = """
        @system pe=1, sm=0
        &out <| pass
        #reduce_3 add |> &out
        """
        outputs = run_program_direct(source, until=500)
        assert 0 in outputs, "PE 0 should exist in outputs"


class TestBuiltinSyntaxValidation:
    """Verify that all built-in macros have valid syntax."""

    def test_all_builtins_parse(self):
        """All built-in macros parse without syntax errors."""
        from asm.builtins import BUILTIN_MACROS

        parser = _get_parser()
        tree = parser.parse(BUILTIN_MACROS)
        assert tree is not None

    def test_permit_inject_defined_in_builtins(self):
        """#permit_inject variadic macro is defined."""
        from asm.builtins import BUILTIN_MACROS

        assert "#permit_inject *targets" in BUILTIN_MACROS, (
            "Expected variadic #permit_inject definition in BUILTIN_MACROS"
        )

    def test_reduce_variants_defined_in_builtins(self):
        """All #reduce_2 through #reduce_4 are defined with op parameter."""
        from asm.builtins import BUILTIN_MACROS

        for i in range(2, 5):
            macro_name = f"#reduce_{i}"
            assert f"{macro_name} op" in BUILTIN_MACROS, (
                f"Expected '{macro_name} op' definition in BUILTIN_MACROS"
            )

            start = BUILTIN_MACROS.find(f"{macro_name} op")
            end = BUILTIN_MACROS.find("\n#", start + 1)
            if end == -1:
                end = len(BUILTIN_MACROS)
            macro_body = BUILTIN_MACROS[start:end]

            assert "${op}" in macro_body, (
                f"{macro_name} should use '${{op}}' parameter for opcode"
            )


class TestBuiltinComposition:
    """Test composition of built-in macros with user-defined code."""

    def test_builtins_dont_interfere_with_user_code(self):
        """Built-in macros don't cause errors in simple user code."""
        source = """
        @system pe=1, sm=0
        &a <| const, 10
        &b <| const, 20
        &sum <| add
        &a |> &sum:L
        &b |> &sum:R
        &out <| pass
        &sum |> &out:L
        """
        graph = run_pipeline(source)
        assert len(graph.errors) == 0, f"Unexpected errors: {graph.errors}"

    def test_user_macros_work_alongside_builtins(self):
        """User-defined macros work in same program as built-ins."""
        source = """
        @system pe=1, sm=0

        #helper |> {
            &internal <| pass
        }

        #helper
        """
        graph = parse_lower_expand(source)

        node_names = list(graph.nodes.keys())
        has_helper = any("#helper_0" in n for n in node_names)
        assert has_helper, f"Expected helper_0 nodes in {node_names}"

    def test_builtin_and_user_macros_in_same_program(self):
        """A program using both built-in and user macros works correctly."""
        source = """
        @system pe=1, sm=0

        #my_const |> {
            &val <| const, 77
        }

        &sink <| pass
        &source <| add, #my_const

        #permit_inject &source |> &sink
        """
        graph = run_pipeline(source)
        assert len(graph.errors) == 0

        node_names = list(graph.nodes.keys())
        has_val = any("&source" in n for n in node_names)
        has_p = any("&p" in n and "permit_inject" in n for n in node_names)
        assert has_val, f"Expected user macro &source in {node_names}"
        assert has_p, f"Expected builtin &p in {node_names}"


class TestLineNumberOffset:
    """Test that line numbers in user code are correct despite built-in prepending."""

    def test_builtin_line_offset_is_tracked(self):
        """Verify that builtin_line_offset is tracked on IRGraph."""
        source = """
        @system pe=1, sm=0
        &const|pe0 <| const, 42
        """
        graph = run_pipeline(source)
        assert graph.builtin_line_offset > 0, "builtin_line_offset should be > 0"

    def test_builtin_offset_allows_error_line_adjustment(self):
        """Verify builtin_line_offset is available for error message adjustment."""
        source = """
        @system pe=1, sm=0
        &c <| const, 42
        """
        graph = run_pipeline(source)

        assert hasattr(graph, "builtin_line_offset")
        assert isinstance(graph.builtin_line_offset, int)