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"""Group conv2D operator declaration and schedule registration for VTA."""

import numpy as np

import tvm
from tvm import te
from tvm import autotvm
import topi

from ..environment import get_env

@autotvm.register_topi_compute("group_conv2d_packed.vta")
def group_conv2d_packed(cfg,
                        data,
                        kernel,
                        strides,
                        padding,
                        dilation,
                        group,
                        out_dtype):
    """ Packed group conv2d nchw function."""
    assert dilation == (1, 1)

    if padding[0]:
        pad_data = topi.nn.pad(data, [0, 0, padding[0], padding[1], 0, 0], name="pad_data")
    else:
        pad_data = data
    assert len(data.shape) == 6
    assert len(kernel.shape) == 6
    assert data.dtype == "int8", data.dtype
    assert kernel.dtype == "int8", kernel.dtype
    assert out_dtype == "int32", out_dtype

    oheight = topi.util.get_const_int((pad_data.shape[2] - kernel.shape[2]) // strides[0] + 1)
    owidth = topi.util.get_const_int((pad_data.shape[3] - kernel.shape[3]) // strides[1] + 1)
    oshape = (data.shape[0], kernel.shape[0], oheight, owidth, data.shape[4], kernel.shape[4])

    ishape = topi.util.get_const_tuple(data.shape)
    kshape = topi.util.get_const_tuple(kernel.shape)
    assert group * kshape[1] == ishape[1]
    assert kshape[0] % group == 0
    d_i = te.reduce_axis((0, kshape[2]), name='d_i')
    d_j = te.reduce_axis((0, kshape[3]), name='d_j')
    k_o = te.reduce_axis((0, kshape[1]), name='k_o')
    k_i = te.reduce_axis((0, kshape[-1]), name='k_i')
    hstride, wstride = strides
    out = te.compute(
        oshape,
        lambda b_o, c_o, i, j, b_i, c_i: te.sum(
            pad_data[b_o, c_o // (kshape[0] // group) * kshape[1] + k_o, i * hstride + d_i,
                     j * wstride + d_j, b_i, k_i].astype(out_dtype) *
            kernel[c_o, k_o, d_i, d_j, c_i, k_i].astype(out_dtype),
            axis=[k_o, d_i, d_j, k_i]),
        name="res", tag="packed_group_conv2d")

    cfg.add_flop(2 * np.prod(topi.util.get_const_tuple(oshape)) *
                 kshape[2] * kshape[3] * ishape[1] * kshape[-1])

    return out


@autotvm.register_topi_schedule("group_conv2d_packed.vta")
def schedule_group_conv2d_packed(cfg, outs):
    """ Schedule the packed conv2d.
    """
    assert len(outs) == 1
    output = outs[0]
    const_ops = []
    ewise_inputs = []
    ewise_ops = []
    conv2d_res = []
    assert output.dtype == "int8"
    assert output.op.input_tensors[0].dtype == "int32"

    def _traverse(op):
        if topi.tag.is_broadcast(op.tag):
            if not op.same_as(output.op):
                if not op.axis:
                    const_ops.append(op)
                else:
                    ewise_ops.append(op)
            for tensor in op.input_tensors:
                if isinstance(tensor.op, tvm.te.PlaceholderOp):
                    ewise_inputs.append((op, tensor))
                else:
                    _traverse(tensor.op)
        else:
            assert op.tag == "packed_group_conv2d"
            conv2d_res.append(op)

    _traverse(output.op)
    assert len(conv2d_res) == 1
    conv2d_stage = conv2d_res[0].output(0)
    s = te.create_schedule(output.op)

    ##### space definition begin #####
    b, c_o, x_i, x_j, _, _ = s[conv2d_stage].op.axis
    c_i, _, _, _ = s[conv2d_stage].op.reduce_axis
    cfg.define_split('tile_b', b, num_outputs=2)
    cfg.define_split('tile_h', x_i, num_outputs=2)
    cfg.define_split('tile_w', x_j, num_outputs=2)
    cfg.define_split('tile_ci', c_i, num_outputs=2)
    cfg.define_split('tile_co', c_o, num_outputs=2)
    cfg.define_knob('oc_nthread', [1, 2])
    cfg.define_knob('h_nthread', [1, 2])
    ###### space definition end ######

    data, kernel = conv2d_stage.op.input_tensors
    if isinstance(data.op, tvm.te.ComputeOp) and "pad" in data.op.tag:
        temp = data.op.input_tensors[0]
        pad_data = data
        data = temp
    else:
        pad_data = None

    env = get_env()

    # setup pad
    if pad_data is not None:
        cdata = pad_data
        s[pad_data].set_scope(env.inp_scope)
    else:
        cdata = s.cache_read(data, env.inp_scope, [conv2d_stage])
    ckernel = s.cache_read(kernel, env.wgt_scope, [conv2d_stage])
    s[conv2d_stage].set_scope(env.acc_scope)

    # cache read input
    cache_read_ewise = []
    for consumer, tensor in ewise_inputs:
        cache_read_ewise.append(
            s.cache_read(tensor, env.acc_scope, [consumer]))

    # set ewise scope
    for op in ewise_ops:
        s[op].set_scope(env.acc_scope)
        s[op].pragma(s[op].op.axis[0], env.alu)

    for op in const_ops:
        s[op].compute_inline()

    # tile
    x_bo, x_co, x_i, x_j, x_bi, x_ci = s[output].op.axis
    x_co0, x_co1 = cfg['tile_co'].apply(s, output, x_co)
    x_i0, x_i1 = cfg['tile_h'].apply(s, output, x_i)
    x_j0, x_j1 = cfg['tile_w'].apply(s, output, x_j)
    s[output].reorder(x_bo, x_i0, x_co0, x_j0, x_co1, x_i1, x_j1, x_bi, x_ci)
    store_pt = x_j0

    # set all compute scopes
    s[conv2d_stage].compute_at(s[output], store_pt)
    for op in ewise_ops:
        s[op].compute_at(s[output], store_pt)

    for tensor in cache_read_ewise:
        s[tensor].compute_at(s[output], store_pt)
        s[tensor].pragma(s[tensor].op.axis[0], env.dma_copy)

    # virtual threading along output channel axes
    if cfg['oc_nthread'].val > 1:
        _, v_t = s[output].split(x_co0, factor=cfg['oc_nthread'].val)
        s[output].reorder(v_t, x_bo)
        s[output].bind(v_t, te.thread_axis("cthread"))

    # virtual threading along spatial rows
    if cfg['h_nthread'].val > 1:
        _, v_t = s[output].split(x_i0, factor=cfg['h_nthread'].val)
        s[output].reorder(v_t, x_bo)
        s[output].bind(v_t, te.thread_axis("cthread"))

    x_bo, x_co, x_i, x_j, x_bi, x_ci = s[conv2d_stage].op.axis
    k_o, d_i, d_j, k_i = s[conv2d_stage].op.reduce_axis
    s[conv2d_stage].reorder(x_bo, k_o, x_j, d_j, d_i, x_co, x_i, x_bi, x_ci, k_i)

    k_o, _ = cfg['tile_ci'].apply(s, conv2d_stage, k_o)
    s[cdata].compute_at(s[conv2d_stage], k_o)
    s[ckernel].compute_at(s[conv2d_stage], k_o)

    # Use VTA instructions
    s[cdata].pragma(s[cdata].op.axis[0], env.dma_copy)
    s[ckernel].pragma(s[ckernel].op.axis[0], env.dma_copy)
    s[conv2d_stage].tensorize(x_bi, env.gemm)
    s[output].pragma(x_co1, env.dma_copy)

    return s
