"""
Builds c utility routines
"""

from . import utility


def write_license(cg):

    license_text = """BSD 3-Clause License

    Copyright (c) 2017, Daniel Smith
    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice, this
      list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above copyright notice,
      this list of conditions and the following disclaimer in the documentation
      and/or other materials provided with the distribution.

    * Neither the name of the copyright holder nor the names of its
      contributors may be used to endorse or promote products derived from
      this software without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."""

    # Write out header
    cg.write("/*", endl="")
    for line in license_text.splitlines():
        line = line.strip()
        cg.write(" * " + line, endl="")

    cg.write(" */", endl="")
    cg.blankline()


### Pybind11 binders


def pybind11_func(cg, name, grad, call_name, max_L):
    """
    A function that builds the PyBind11 wrappers for the different pybind11 funcs.
    """

    # Figure out what we need to add per deriv
    deriv_indices = utility.get_deriv_indices(grad)

    # Write out wrapper functions
    sig = """void %s(int L, py::array_t<double> arr_xyz, py::array_t<double> arr_coeffs,
py::array_t<double> arr_exponents, py::array_t<double> arr_center, bool spherical,
py::array_t<double> arr_out""" % name

    # Pad out deriv outputs
    for cart in deriv_indices:
        sig += ", py::array_t<double> arr_%s_out" % cart

    sig += ")"
    cg.start_c_block(sig)
    cg.blankline()

    # Grab the pointers
    cg.write('// Grab array pointers')
    cg.write('auto xyz = arr_xyz.unchecked<2>()')
    cg.write('auto coeffs = arr_coeffs.unchecked<1>()')
    cg.write('auto exponents = arr_exponents.unchecked<1>()')
    cg.write('auto center = arr_center.unchecked<1>()')
    cg.write('auto out = arr_out.mutable_unchecked<2>()')

    # Pad out deriv pointers
    for cart in deriv_indices:
        cg.write("auto out_%s = arr_%s_out.mutable_unchecked<2>()" % (cart, cart))

    cg.blankline()

    # Run through checks
    cg.write('// XYZ is of size 3')
    cg.start_c_block('if (L > %d)' % max_L)
    cg.write(
        '    throw std::invalid_argument("Exceeded compiled angular momentum of %d. Please recompile with a higher angular momentum.\\n")'
        % max_L)
    cg.close_c_block()

    cg.write('// XYZ is of size 3')
    cg.start_c_block('if (arr_xyz.shape(0) != 3)')
    cg.write('    throw std::length_error("Length of XYZ array must be (3, n).\\n")')
    cg.close_c_block()
    cg.blankline()

    cg.write('// Coeff matches exponent shape')
    cg.start_c_block('if (coeffs.shape(0) != exponents.shape(0))')
    cg.write('    throw std::length_error("Length of coefficients and exponents must match.\\n")')
    cg.close_c_block()
    cg.blankline()

    cg.write('// Center is of size 3')
    cg.start_c_block('if (center.shape(0) != 3)')
    cg.write('    throw std::length_error("Length of center vector must be 3 (X, Y, Z).\\n")')
    cg.close_c_block()
    cg.blankline()

    cg.write('// Make sure output length matches')
    cg.write('unsigned long nsize')
    cg.start_c_block('if (spherical)')
    cg.write('    nsize = 2 * L + 1')
    cg.write('} else {', endl="")
    cg.write('    nsize = ((L + 2) * (L + 1)) / 2')
    cg.close_c_block()
    cg.blankline()

    cg.start_c_block('if (out.shape(0) != nsize)')
    cg.write('    throw std::length_error("Size of the output array does not match the angular momentum.\\n")')
    cg.close_c_block()

    for cart in deriv_indices:
        cg.start_c_block('if (out_%s.shape(0) != nsize)' % cart)
        cg.write('    throw std::length_error("Size of the output %s array does not match the angular momentum.\\n")' %
                 cart.upper())
        cg.close_c_block()
    cg.blankline()

    cg.write('// Ensure lengths match')
    cg.start_c_block('if (out.shape(1) != arr_xyz.shape(1))')
    cg.write('    throw std::length_error("Size of the output array and XYZ array must be the same.\\n")')
    cg.close_c_block()

    # Pad out deriv length checkers
    for cart in deriv_indices:
        cg.start_c_block('if (out_%s.shape(1) != arr_xyz.shape(1))' % cart)
        cg.write('    throw std::length_error("Size of the output %s array and XYZ array must be the same.\\n")' %
                 cart.upper())
        cg.close_c_block()
    cg.blankline()

    cg.write("// Call the GG helper function")
    call_func = call_name + "(L, xyz.shape(1)"
    call_func += ", xyz.data(0, 0), xyz.data(1, 0), xyz.data(2, 0)"
    call_func += ", coeffs.shape(0), coeffs.data(0), exponents.data(0)"
    call_func += ", center.data(0)"
    call_func += ", spherical"
    call_func += ", out.mutable_data(0, 0)"
    for cart in deriv_indices:
        call_func += ", out_%s.mutable_data(0, 0)" % cart
    call_func += ")"

    cg.write(call_func)

    cg.close_c_block()


def pybind11_transpose(cg, func_name, wrapper_name):
    """
    Wraps the transpose functions in pybind11
    """

    sig = "void %s(py::array_t<double> arr_input" % wrapper_name
    sig += ", py::array_t<double> arr_output)"

    cg.start_c_block(sig)
    cg.write("auto input = arr_input.unchecked<2>()")
    cg.write("auto output = arr_output.mutable_unchecked<2>()")
    cg.write("unsigned long n = input.shape(0)")
    cg.write("unsigned long m = input.shape(1)")
    cg.blankline()

    cg.write('// Check shapes')
    cg.start_c_block('if (input.shape(0) != output.shape(1))')
    cg.write('    throw std::length_error("Input tranpose shape 0 does not match output transpose shape 1.\\n")')
    cg.close_c_block()
    cg.blankline()

    cg.start_c_block('if (input.shape(1) != output.shape(0))')
    cg.write('    throw std::length_error("Input tranpose shape 1 does not match output transpose shape 0.\\n")')
    cg.close_c_block()
    cg.blankline()

    cg.write("%s(n, m, input.data(0, 0), output.mutable_data(0, 0))" % func_name)

    cg.close_c_block()


### Tranposers


def naive_transpose(cg):
    """
    A completely naive tranpose to swap data
    """

    sig = "void gg_naive_transpose(unsigned long n, unsigned long m, const double* __restrict__ input, double* __restrict__ output)"
    cg.start_c_block(sig)

    cg.start_c_block("for (unsigned long i = 0; i < n; i++)")

    # Inner block
    cg.start_c_block("for (unsigned long j = 0; j < m; j++)")
    cg.write("output[j * n + i] = input[i * m + j]")
    cg.close_c_block()

    # Outer block
    cg.close_c_block()

    cg.close_c_block()
    return sig


def fast_transpose(cg, inner_block):
    """
    Builds a fast transpose using an internal blocking scheme in an attempt to vectorize IO from/to DRAM
    """

    sig = "void gg_fast_transpose(unsigned long n, unsigned long m, const double* __restrict__ input, double* __restrict__ output)"
    cg.start_c_block(sig)
    cg.blankline()

    cg.write("// Temps")
    cg.write("double tmp[%d]  __attribute__((aligned(64)))" % (inner_block * inner_block))

    cg.write("// Sizing")
    cg.write("unsigned long nblocks = n / %d" % inner_block)
    cg.write("nblocks += (n %% %d) ? 1 : 0" % inner_block)

    cg.write("unsigned long mblocks = m / %d" % inner_block)
    cg.write("mblocks += (m %% %d) ? 1 : 0" % inner_block)
    # cg.write('printf("Blocks: %ld %ld\\n", nblocks, mblocks)')

    cg.write("// Outer blocks")
    cg.start_c_block("for (unsigned long nb = 0; nb < nblocks; nb++)")
    cg.write("const unsigned long nstart = nb * %d" % inner_block)
    cg.write("unsigned long nremain = ((nstart + %d) > n) ? (n - nstart) : %d" % (inner_block, inner_block))

    cg.start_c_block("for (unsigned long mb = 0; mb < mblocks; mb++)")
    cg.write("const unsigned long mstart = mb * %d" % inner_block)
    cg.write("unsigned long mremain = ((mstart + %d) > m) ? (m - mstart) : %d" % (inner_block, inner_block))

    # cg.start_c_block("if ((nremain == 0) & (mremain > 0))")
    # cg.write("nremain++;")
    # cg.close_c_block()

    # cg.start_c_block("if ((mremain == 0) & (nremain > 0))")
    # cg.write("mremain++;")
    # cg.close_c_block()
    # cg.write('printf("(n,m)%ld %ld | %ld %ld\\n", nb, mb, nremain, mremain)')

    # Pull block
    cg.write("// Copy data to inner block")
    # cg.write('printf("%ld %ld | %ld\\n ", mstart, nstart, start)')
    cg.start_c_block("for (unsigned long l = 0; l < nremain; l++)")
    cg.write("const unsigned long start = (nstart + l) * m + mstart")
    # cg.write("PRAGMA_VECTORIZE", endl="")
    cg.start_c_block("for (unsigned long k = 0; k < mremain; k++)")

    # cg.write("tmp[l * %d + k] = input[start + k]" % inner_block)
    cg.write("tmp[k * %d + l] = input[start + k]" % inner_block)

    # cg.write('printf("(%ld %ld %lf) ", l * 2+ k, start +k, input[start + k])')
    # cg.write('printf("%%lf ", tmp[k * %d + l])' % inner_block)
    cg.close_c_block()
    cg.close_c_block()
    # cg.write('printf("\\n--\\n")')
    # cg.start_c_block("for (unsigned long k = 0; k < 4; k++)")
    # cg.write('printf("%lf ", tmp[k])')
    # cg.close_c_block()
    # cg.write('printf("\\n--\\n")')

    # Tranpose block
    # cg.write("// Transpose inner block")
    # cg.start_c_block("for (unsigned long k = 0; k < %d; k++)" % inner_block)
    # cg.start_c_block("for (unsigned long l = k; l < %d; l++)" % inner_block)
    # # cg.write('printf("%ld %ld \\n", k, l)')
    # cg.write("const double itmp = tmp[l * %d + k]" % inner_block)
    # cg.write("tmp[l * %d + k] = tmp[k * %d + l]" % (inner_block, inner_block))
    # cg.write("tmp[k * %d + l] = itmp" % (inner_block))
    # cg.close_c_block()
    # cg.close_c_block()
    # cg.write('printf("--\\n")')
    # cg.start_c_block("for (unsigned long k = 0; k < 4; k++)")
    # cg.write('printf("%lf ", tmp[k])')
    # cg.close_c_block()
    # cg.write('printf("\\n--\\n")')

    # Push block
    cg.write("// Copy data to inner block")
    cg.start_c_block("for (unsigned long k = 0; k < mremain; k++)")
    cg.write("const unsigned long start = (mstart + k) * n + nstart")
    # cg.write("PRAGMA_VECTORIZE", endl="")
    cg.start_c_block("for (unsigned long l = 0; l < nremain; l++)")
    # cg.write('printf("(k,l) %ld %ld | %ld\\n", k, l, start+l)')

    cg.write("output[start + l] = tmp[k * %d + l]" % inner_block)
    cg.close_c_block()
    cg.close_c_block()
    # cg.write('printf("--------\\n")')

    # cg.start_c_block("for (unsigned long k = 0; k < %d; k++)" % inner_block)
    # cg.start_c_block("for (unsigned long l = 0; l < %d; l++)" % inner_block)
    # cg.write("tmp[k * %d + l] = 0.0" % inner_block)
    # cg.close_c_block()
    # cg.close_c_block()

    # Outer block
    cg.close_c_block()
    cg.close_c_block()

    cg.close_c_block()

    return sig


### Data copiers


def block_copy(cg):
    """
    Copies a small block of data back to a larger array.
    """

    sig = "void block_copy(unsigned long n, unsigned long m, const double* __restrict__ input, unsigned long is, double* __restrict__ output, unsigned long os, const int trans)"
    # nout, nremain

    cg.start_c_block(sig)
    cg.blankline()
    cg.start_c_block("for (unsigned long i = 0; i < n; i++)")
    cg.write("const unsigned long out_shift = i * os")
    cg.write("const unsigned long inp_shift = i * is")

    # Inner copy over block
    cg.blankline()
    # cg.write("PRAGMA_VECTORIZE", endl="")
    cg.start_c_block("for (unsigned long j = 0; j < m; j++)")
    # cg.write("output[is * j + i] = input[i * is + j]")
    cg.write("output[out_shift + j] = input[inp_shift + j]")
    cg.close_c_block()

    # Close i loop
    cg.close_c_block()

    # Close func
    cg.close_c_block()
    return sig
