from moe import MOELayer, MOELayer_raw
import torch
from torch import nn
import time
import sys


dev_name = 'cuda:1'


def perf():
    torch.manual_seed(42 + torch.distributed.get_rank())
    torch.cuda.manual_seed(42 + torch.distributed.get_rank())
    
    batch_size = int(sys.argv[1])
    in_feat = int(sys.argv[2])
    out_feat = int(sys.argv[3])
    num_expert = int(sys.argv[4])

    inp = torch.rand(batch_size, in_feat).cuda(dev_name)
    gate = torch.randint(low=0, 
            high=num_expert * torch.distributed.get_world_size(), 
            size=(batch_size, ), requires_grad=False).int().cuda(dev_name)

    moe = MOELayer(num_expert, in_feat, out_feat).cuda(dev_name)
    moe.train()

    o = moe(inp, gate)

    o = moe(inp, gate)
    o = moe(inp, gate)
    o = moe(inp, gate)

    n_runs = 16
    tott = 0.
    backt = 0.
    maxt = 0.
    sqtot = 0.
    for i in range(n_runs):
        gate = torch.randint(low=0, 
                high=num_expert * torch.distributed.get_world_size(), 
                size=(batch_size, ), requires_grad=False).int().cuda(dev_name)
        ts = time.time()
        o = moe(inp, gate)
        te = time.time()

        loss = o.sum()

        bts = time.time()
        loss.backward()
        bte = time.time()

        tott += te - ts
        sqtot += (te - ts)**2
        maxt = max(maxt, te - ts)
        backt = bte - bts

    gflops = 2e-9 * n_runs * in_feat * out_feat * batch_size / tott
    print('Time mean/max/stdev/back {:.3f} {:.3f} {:.3f} {:.3f} ms, {:.3f} GFLOPs'.format(
        tott * 1e3 / n_runs, maxt * 1e3, 
        (sqtot / n_runs - (tott / n_runs)**2) * 1e3 / n_runs, 
        backt * 1e3 / n_runs, gflops))


def test_module(moe, linear, inp, gate):
    linear.zero_grad()
    moe.zero_grad()
    x = (linear(inp))
    output = moe(x, gate)
    y = output.mean()
    y.backward()
    return output, moe.weight.grad, linear.weight.grad, linear.bias.grad


def test():
    torch.manual_seed(42)
    torch.cuda.manual_seed(42)
    batch_size = 4
    num_expert = 2
    in_feat = 6
    out_feat = 7

    linear = nn.Linear(in_feat, in_feat).cuda()

    if world_size > 1:
        moe = MOELayer(num_expert, in_feat, out_feat, world_size).cuda()
    else:
        moe = MOELayer(num_expert, in_feat, out_feat).cuda()
    moe_raw = MOELayer_raw(num_expert, in_feat, out_feat).cuda()
    moe_raw.weight.data = moe.weight.data.clone()

    inp = torch.rand(batch_size, in_feat).cuda()
    gate = torch.randint(low=0, 
            high=num_expert * world_size, 
            size=(batch_size,), 
            requires_grad=False).int().cuda()
    # gate = torch.Tensor([0, 1, 0, 1]).int().cuda()

    moe_out = test_module(moe, linear, inp.clone(), gate.clone())
    print('hhh')
    return
    raw_out = test_module(moe_raw, linear, inp.clone(), gate.clone())

    names = ['Out', 'Moe wei', 'Linear wei', 'Linear bias']
    for name, mo, ro in zip(names, moe_out, raw_out):
        err = (mo - ro).abs().sum()
        print('{} abs err {}'.format(name, err))


def test_dp():
    torch.manual_seed(42)
    torch.cuda.manual_seed(42)
    batch_size = 6
    num_expert = 4
    in_feat = 2
    out_feat = 3

    inp = torch.rand(batch_size, in_feat).cuda()
    gate = torch.randint(low=0, high=num_expert, size=(batch_size, ), requires_grad=False).int().cuda()

    print("data parallel of a nn.Linear model")
    linear = nn.Linear(in_feat, in_feat).cuda()
    linear_dp = torch.nn.DataParallel(linear, device_ids=[0,1,2])
    output = linear_dp(inp)
    print("successful!")

    print("data parallel of our MoE model")
    moe = MOELayer(num_expert, in_feat, out_feat).cuda()
    moe_dp = torch.nn.DataParallel(moe, device_ids=[0,1,2])
    for i in range(5):
        output = moe_dp(inp, gate)


if __name__ == '__main__':
    torch.distributed.init_process_group(backend='mpi')
    world_size = torch.distributed.get_world_size()
    if world_size == 1:
        world_size = None
    test()
    # print('{} / {}'.format(torch.distributed.get_rank(), torch.distributed.get_world_size()))
    # perf()