from __future__ import annotations
from tvm import tir, IRModule
from tvm.target import Target
import tilelang
from tilelang.transform import PassContext
from tilelang.contrib.nvcc import have_tma, is_hopper


def allow_warp_specialized(pass_ctx: PassContext | None = None,
                           target: Target | None = None) -> bool:
    # avoid circular import
    from tilelang.jit.adapter.utils import is_cuda_target

    if pass_ctx is None:
        pass_ctx = tilelang.transform.get_pass_context()
    if (not is_cuda_target(target)) or (not have_tma(target)):
        return False
    disable_warp_specialized = pass_ctx.config.get("tl.disable_warp_specialized", False)
    return not disable_warp_specialized


def allow_tma_and_warp_specialized(pass_ctx: PassContext | None = None,
                                   target: Target | None = None) -> bool:
    if pass_ctx is None:
        pass_ctx = tilelang.transform.get_pass_context()
    if not have_tma(target):
        return False
    disable_tma_lower = pass_ctx.config.get("tl.disable_tma_lower", False)
    return not disable_tma_lower and allow_warp_specialized(pass_ctx=pass_ctx, target=target)


def allow_fence_proxy(target: Target | None = None) -> bool:
    return have_tma(target)


def allow_vectorize(pass_ctx: PassContext | None = None) -> bool:
    if pass_ctx is None:
        pass_ctx = tilelang.transform.get_pass_context()
    disable_vectorize = pass_ctx.config.get("tir.disable_vectorize", False)
    return not disable_vectorize


def allow_global_thread_synchronization(pass_ctx: PassContext | None = None) -> bool:
    if pass_ctx is None:
        pass_ctx = tilelang.transform.get_pass_context()
    enable_global_thread_sync = pass_ctx.config.get("tir.detect_global_barrier", False)
    return enable_global_thread_sync


def should_enable_aggressive_merge(pass_ctx: PassContext | None = None,
                                   target: Target | None = None) -> bool:
    if pass_ctx is None:
        pass_ctx = tilelang.transform.get_pass_context()
    enable_aggressive_merge = bool(
        pass_ctx.config.get(tilelang.PassConfigKey.TL_ENABLE_AGGRESSIVE_SHARED_MEMORY_MERGE, False))
    if allow_warp_specialized(pass_ctx=pass_ctx, target=target):
        # This is a workaround to avoid the bug in the MergeSharedMemoryAllocations pass
        # when warp specialization is enabled, as different warp threads may access different
        # buffers, but the liveness analysis is hard because we need to do pipeline.
        enable_aggressive_merge = False
    return enable_aggressive_merge


def should_force_let_inline(pass_ctx: PassContext | None = None) -> bool:
    if pass_ctx is None:
        pass_ctx = tilelang.transform.get_pass_context()
    return bool(pass_ctx and pass_ctx.config.get(tilelang.PassConfigKey.TL_FORCE_LET_INLINE, False))


def LowerAndLegalize(mod: IRModule, target: Target) -> IRModule:
    # Bind the target device information to the module
    """
    Bind target information and progressively legalize and lower frontend Tile IR into a form suitable for downstream optimization and codegen.

    This pass pipeline:
    - Binds the provided target to the module.
    - Legalizes frontend Tile IR into TVM-compatible constructs.
    - Simplifies expressions.
    - Configures reducer layouts and performs layout inference for fragments and shared memory.
    - Lowers high-level tile operations and L2 persistent maps.
    - Legalizes vectorized loops and inserts safety checks for memory accesses.
    - Re-simplifies to remove redundancies introduced by safety checks.
    - Attempts loop vectorization for dynamic-shaped loops.

    Parameters:
        mod (IRModule): The input IR module containing frontend Tile IR.
        target (Target): Target device information to bind into the module.

    Returns:
        IRModule: The transformed module, ready for target-specific optimization passes.
    """
    mod = tir.transform.BindTarget(target)(mod)

    if should_force_let_inline():
        # Force-let inline whenever the pass config requests it.
        mod = tilelang.transform.LetInline()(mod)
    # Add wrapper for single buf store
    mod = tilelang.transform.AddWrapperForSingleBufStore()(mod)
    # Inject assumes to speedup tvm prover
    mod = tilelang.transform.InjectAssumes()(mod)
    # Simplify the IR expressions
    mod = tilelang.transform.Simplify()(mod)
    # Set layouts for reducers
    mod = tilelang.transform.LayoutReducer()(mod)
    # Infer memory layouts for fragments and shared memory
    mod = tilelang.transform.LayoutInference()(mod)
    # Lower high-level tile operations to low-level operations
    mod = tilelang.transform.LowerTileOp()(mod)
    # Lower l2 persistent map
    mod = tilelang.transform.LowerL2Persistent()(mod)
    # Legalize vectorized loops to ensure they are valid
    mod = tilelang.transform.LegalizeVectorizedLoop()(mod)
    # Add safety checks for memory accesses
    mod = tilelang.transform.LegalizeSafeMemoryAccess()(mod)
    # Simplify again to clean up any duplicated conditions
    # that may have been introduced by safety checks
    # use an enhanced pass to simplify the dynamic symbolics
    # TODO(lei): return to tir pass when kSymbolicBound simplification
    # is merged into tvm.
    mod = tilelang.transform.Simplify()(mod)
    # Try to vectorize loop with dynamic shape
    mod = tilelang.transform.LoopVectorizeDynamic()(mod)
    return mod


def OptimizeForTarget(mod: IRModule, target: Target) -> IRModule:
    pass_ctx = tilelang.transform.get_pass_context()
    # Lower the barrier.arrive into specific initialization slot
    mod = tilelang.transform.LowerSharedBarrier()(mod)
    # Lower the shared.tmem into specific initialization slot
    mod = tilelang.transform.LowerSharedTmem()(mod)
    # which may be introduced by the LegalizeSafeMemoryAccess
    if allow_tma_and_warp_specialized(pass_ctx=pass_ctx, target=target):
        mod = tilelang.transform.IfStmtBinding()(mod)
        mod = tilelang.transform.MultiVersionBuffer()(mod)
        mod = tilelang.transform.WarpSpecialized()(mod)
        mod = tilelang.transform.InjectTmaBarrier()(mod)
        # if tma is not enabled, we can also do pipeline planning
        # to get better performance with async copy
        mod = tilelang.transform.PipelinePlanning()(mod)
        mod = tilelang.transform.InjectSoftwarePipeline()(mod)
        # warp_specialized pass will pack the if stmt into the block
        # so we need to lower the opaque block first
        mod = tilelang.transform.LowerOpaqueBlock()(mod)
        mod = tilelang.transform.MergeIfStmt()(mod)
        if is_hopper(target):
            mod = tilelang.transform.RewriteWgmmaSync()(mod)
        mod = tilelang.transform.InjectFenceProxy()(mod)
    else:
        mod = tilelang.transform.IfStmtBinding()(mod)
        mod = tir.transform.PlanAndUpdateBufferAllocationLocation()(mod)
        mod = tilelang.transform.PipelinePlanning()(mod)
        mod = tilelang.transform.InjectSoftwarePipeline()(mod)
        mod = tilelang.transform.MergeIfStmt()(mod)
        if allow_fence_proxy(target=target):
            # in hopper device, wgmma is an async proxy
            # so we need to inject a fence proxy before it
            mod = tilelang.transform.InjectFenceProxy()(mod)

    mod = tilelang.transform.LowerOpaqueBlock()(mod)
    mod = tir.transform.NarrowDataType(32)(mod)
    mod = tilelang.transform.FlattenBuffer()(mod)
    # ConfigIndexBitwidth must be applied after FlattenBuffer
    # as it will flatten index computing
    mod = tilelang.transform.ConfigIndexBitwidth()(mod)
    mod = tir.transform.Simplify()(mod)
    mod = tilelang.transform.VectorizeLoop(enable_vectorize=allow_vectorize(pass_ctx=pass_ctx))(mod)
    mod = tilelang.transform.StorageRewrite()(mod)
    mod = tir.transform.UnrollLoop()(mod)
    mod = tir.transform.RenormalizeSplitPattern()(mod)
    mod = tir.transform.Simplify()(mod)
    mod = tir.transform.RemoveNoOp()(mod)
    mod = tir.transform.RewriteUnsafeSelect()(mod)
    mod = tir.transform.HoistIfThenElse()(mod)

    mod = tir.transform.VerifyMemory()(mod)
    mod = tir.transform.AnnotateEntryFunc()(mod)
    # TODO(lei): This is a hack to make sure the
    # thread level allreduce pass can be applied
    # in TL. As Tl only use one thread dimension
    # the var binding information will be lost
    # in the lowering process with Legalization
    # and Simplify pass.
    # We can find a way better to create var instead
    # of putting the LowerThreadAllreduce before
    # the Legalization.
    mod = tir.transform.InferFragment()(mod)
    mod = tilelang.transform.LowerThreadAllreduce()(mod)

    mod = tilelang.transform.LowerHopperIntrin()(mod)
    # Global Barrier Synchronization must be applied before
    # SplitHostDevice pass, as the global barrier
    if allow_global_thread_synchronization():
        mod = tilelang.transform.ThreadSync("global")(mod)
    mod = tilelang.transform.AnnotateDeviceRegions()(mod)
    mod = tilelang.transform.SplitHostDevice()(mod)
    # MergeSharedMemoryAllocations must be applied after SplitHostDevice
    # because the merged allocation site is at the beginning of each device function
    enable_aggressive_merge = should_enable_aggressive_merge(pass_ctx=pass_ctx, target=target)
    mod = tilelang.transform.MergeSharedMemoryAllocations(
        enable_aggressive_merge=enable_aggressive_merge)(
            mod)
    mod = tilelang.transform.ThreadSync("shared")(mod)
    mod = tilelang.transform.ThreadSync("shared.dyn")(mod)
    # Inject PTX async copy must behind the thread sync pass
    # as ptx async copy won't be recognized as a valid buffer load
    mod = tilelang.transform.InjectPTXAsyncCopy()(mod)
    if allow_tma_and_warp_specialized(pass_ctx=pass_ctx, target=target):
        mod = tilelang.transform.AnnotateWarpGroupRegAlloc()(mod)
    mod = tilelang.transform.MakePackedAPI()(mod)
    mod = tilelang.transform.LowerDeviceKernelLaunch()(mod)

    # Transform threadblock to persistent threadblock
    mod = tilelang.transform.PersistThreadblock()(mod)

    return mod
