/*
 * (C) Copyright 2013 ECMWF.
 *
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
 * In applying this licence, ECMWF does not waive the privileges and immunities
 * granted to it by virtue of its status as an intergovernmental organisation
 * nor does it submit to any jurisdiction.
 */

#include "atlas/functionspace/BlockStructuredColumns.h"

#include <fstream>
#include <iomanip>
#include <mutex>
#include <sstream>
#include <string>

#include "eckit/utils/MD5.h"

#include "atlas/array/Array.h"
#include "atlas/array/MakeView.h"
#include "atlas/domain.h"
#include "atlas/field/FieldSet.h"
#include "atlas/grid/Distribution.h"
#include "atlas/grid/Partitioner.h"
#include "atlas/grid/StructuredGrid.h"
#include "atlas/grid/StructuredPartitionPolygon.h"
#include "atlas/library/Library.h"
#include "atlas/mesh/Mesh.h"
#include "atlas/parallel/Checksum.h"
#include "atlas/parallel/mpi/mpi.h"
#include "atlas/parallel/omp/fill.h"
#include "atlas/parallel/omp/omp.h"
#include "atlas/runtime/Exception.h"
#include "atlas/runtime/Trace.h"
#include "atlas/util/Checksum.h"
#include "atlas/util/CoordinateEnums.h"
#include "atlas/util/detail/Cache.h"

namespace atlas {
namespace functionspace {
namespace detail {

namespace {

template <class ValueType>
void block_copy(const Field sloc, Field loc, const functionspace::detail::BlockStructuredColumns& fs) {
    if (sloc.variables() and sloc.levels()) {
        auto loc_v  = array::make_view<ValueType, 4>(loc);
        auto sloc_v = array::make_view<ValueType, 3>(sloc);
        for (idx_t jblk = 0; jblk < fs.nblks(); ++jblk) {
            const idx_t blk_size = fs.block_size(jblk);
            const idx_t blk_begin = fs.block_begin(jblk);
            for (idx_t jvar = 0; jvar < sloc.shape(2); ++jvar) {
                for (idx_t jlev = 0; jlev < sloc.shape(1); ++jlev) {
                    for (idx_t jrof = 0; jrof < blk_size; ++jrof) {
                        loc_v(jblk, jvar, jlev, jrof) = sloc_v(blk_begin+jrof, jlev, jvar);
                    }
                }
            }
        }
    }
    else if (not sloc.variables() and sloc.levels()) {
        auto loc_v  = array::make_view<ValueType, 3>(loc);
        auto sloc_v = array::make_view<ValueType, 2>(sloc);
        for (idx_t jblk = 0; jblk < fs.nblks(); ++jblk) {
            const idx_t blk_size = fs.block_size(jblk);
            const idx_t blk_begin = fs.block_begin(jblk);
            for (idx_t jlev = 0; jlev < sloc.shape(1); ++jlev) {
                for (idx_t jrof = 0; jrof < blk_size; ++jrof) {
                    loc_v(jblk, jlev, jrof) = sloc_v(blk_begin+jrof, jlev);
                }
            }
        }
    }
    else if (sloc.variables() and not sloc.levels()) {
        auto loc_v  = array::make_view<ValueType, 3>(loc);
        auto sloc_v = array::make_view<ValueType, 2>(sloc);
        for (idx_t jblk = 0; jblk < fs.nblks(); ++jblk) {
            const idx_t blk_size = fs.block_size(jblk);
            const idx_t blk_begin = fs.block_begin(jblk);
            for (idx_t jvar = 0; jvar < sloc.shape(1); ++jvar) {
                for (idx_t jrof = 0; jrof < blk_size; ++jrof) {
                    loc_v(jblk, jvar, jrof) = sloc_v(blk_begin+jrof, jvar);
                }
            }
        }
    }
    else {
        auto loc_v  = array::make_view<ValueType, 2>(loc);
        auto sloc_v = array::make_view<ValueType, 1>(sloc);
        for (idx_t jblk = 0; jblk < fs.nblks(); ++jblk) {
            const idx_t blk_size = fs.block_size(jblk);
            const idx_t blk_begin = fs.block_begin(jblk);
            for (idx_t jrof = 0; jrof < blk_size; ++jrof) {
                loc_v(jblk, jrof) = sloc_v(blk_begin+jrof);
            }
        }
    }
}

template <class ValueType>
void rev_block_copy(const Field loc, Field sloc, const functionspace::detail::BlockStructuredColumns& fs) {
    if (loc.variables() and loc.levels()) {
        auto loc_v  = array::make_view<ValueType, 4>(loc);
        auto sloc_v = array::make_view<ValueType, 3>(sloc);
        for (idx_t jblk = 0; jblk < fs.nblks(); ++jblk) {
            const idx_t blk_size = fs.block_size(jblk);
            const idx_t blk_begin = fs.block_begin(jblk);
            for (idx_t jvar = 0; jvar < sloc.shape(2); ++jvar) {
                for (idx_t jlev = 0; jlev < sloc.shape(1); ++jlev) {
                    for (idx_t jrof = 0; jrof < blk_size; ++jrof) {
                        sloc_v(blk_begin+jrof, jlev, jvar) = loc_v(jblk, jvar, jlev, jrof);
                    }
                }
            }
        }
    }
    else if (not loc.variables() and loc.levels()) {
        auto loc_v  = array::make_view<ValueType, 3>(loc);
        auto sloc_v = array::make_view<ValueType, 2>(sloc);
        for (idx_t jblk = 0; jblk < fs.nblks(); ++jblk) {
            const idx_t blk_size = fs.block_size(jblk);
            const idx_t blk_begin = fs.block_begin(jblk);
            for (idx_t jlev = 0; jlev < sloc.shape(1); ++jlev) {
                for (idx_t jrof = 0; jrof < blk_size; ++jrof) {
                    sloc_v(blk_begin+jrof, jlev) = loc_v(jblk, jlev, jrof);
                }
            }
        }
    }
    else if (loc.variables() and not loc.levels()) {
        auto loc_v  = array::make_view<ValueType, 3>(loc);
        auto sloc_v = array::make_view<ValueType, 2>(sloc);
        for (idx_t jblk = 0; jblk < fs.nblks(); ++jblk) {
            const idx_t blk_size = fs.block_size(jblk);
            const idx_t blk_begin = fs.block_begin(jblk);
            for (idx_t jvar = 0; jvar < sloc.shape(1); ++jvar) {
                for (idx_t jrof = 0; jrof < blk_size; ++jrof) {
                    sloc_v(blk_begin+jrof, jvar) = loc_v(jblk, jvar, jrof);
                }
            }
        }
    }
    else {
        auto loc_v  = array::make_view<ValueType, 2>(loc);
        auto sloc_v = array::make_view<ValueType, 1>(sloc);
        for (idx_t jblk = 0; jblk < fs.nblks(); ++jblk) {
            const idx_t blk_size = fs.block_size(jblk);
            const idx_t blk_begin = fs.block_begin(jblk);
            for (idx_t jrof = 0; jrof < blk_size; ++jrof) {
                sloc_v(blk_begin+jrof) = loc_v(jblk, jrof);
            }
        }
    }
}


void transpose_nonblocked_to_blocked(const Field& nonblocked, Field& blocked, const functionspace::detail::BlockStructuredColumns& fs) {
    auto kind = nonblocked.datatype().kind();
    if (kind == array::DataType::kind<int>()) {
        block_copy<int>(nonblocked, blocked, fs);
    }
    else if (kind == array::DataType::kind<long>()) {
        block_copy<long>(nonblocked, blocked, fs);
    }
    else if (kind == array::DataType::kind<float>()) {
        block_copy<float>(nonblocked, blocked, fs);
    }
    else if (kind == array::DataType::kind<double>()) {
        block_copy<double>(nonblocked, blocked, fs);
    }
    else {
        throw_Exception("datatype not supported", Here());
    }
}

void transpose_blocked_to_nonblocked(const Field& blocked, Field& nonblocked, const functionspace::detail::BlockStructuredColumns& fs) {
    auto kind = blocked.datatype().kind();
    if (kind == array::DataType::kind<int>()) {
        rev_block_copy<int>(blocked, nonblocked, fs);
    }
    else if (kind == array::DataType::kind<long>()) {
        rev_block_copy<long>(blocked, nonblocked, fs);
    }
    else if (kind == array::DataType::kind<float>()) {
        rev_block_copy<float>(blocked, nonblocked, fs);
    }
    else if (kind == array::DataType::kind<double>()) {
        rev_block_copy<double>(blocked, nonblocked, fs);
    }
    else {
        throw_Exception("datatype not supported", Here());
    }
}


}// namespace

array::ArrayShape BlockStructuredColumns::config_shape(const eckit::Configuration& config) const {
    array::ArrayShape shape;

    bool global = false;
    config.get("global", global);
    if (global) {
        return structuredcolumns_->config_shape(config);
    }
    else {
        shape.emplace_back(nblks_);
        idx_t variables(0);
        config.get("variables", variables);
        if (variables > 0) {
            shape.emplace_back(variables);
        }
        idx_t levels(structuredcolumns_->levels());
        config.get("levels", levels);
        if (levels > 0) {
            shape.emplace_back(levels);
        }
        shape.emplace_back(nproma_);
    }
    return shape;
}

array::ArraySpec BlockStructuredColumns::config_spec(const eckit::Configuration& config) const {
    return array::ArraySpec(config_shape(config), structuredcolumns_->config_alignment(config));
}

// ----------------------------------------------------------------------------
// Constructor
// ----------------------------------------------------------------------------
BlockStructuredColumns::BlockStructuredColumns(const Grid& grid, const eckit::Configuration& config):
    BlockStructuredColumns::BlockStructuredColumns(grid, grid::Partitioner(), config) {}

BlockStructuredColumns::BlockStructuredColumns(const Grid& grid, const grid::Partitioner& p, const eckit::Configuration& config):
    BlockStructuredColumns(grid, Vertical(config), p, config) {}

BlockStructuredColumns::BlockStructuredColumns(const Grid& grid, const grid::Distribution& distribution,
                                     const eckit::Configuration& config):
    BlockStructuredColumns(grid, distribution, Vertical(config), config) {}

BlockStructuredColumns::BlockStructuredColumns(const Grid& grid, const grid::Distribution& distribution, const Vertical& vertical,
                                     const eckit::Configuration& config):
    structuredcolumns_(new StructuredColumns(grid, distribution, vertical, config)),
    structuredcolumns_handle_(structuredcolumns_){
    setup(config);
}

BlockStructuredColumns::BlockStructuredColumns(const Grid& grid, const Vertical& vertical, const eckit::Configuration& config):
    BlockStructuredColumns(grid, vertical, grid::Partitioner(), config) {}

BlockStructuredColumns::BlockStructuredColumns(const Grid& grid, const Vertical& vertical, const grid::Partitioner& p,
                                     const eckit::Configuration& config):
    structuredcolumns_(new StructuredColumns(grid, vertical, p, config)),
    structuredcolumns_handle_(structuredcolumns_){
    setup(config);
}

// ----------------------------------------------------------------------------
// Create Field
// ----------------------------------------------------------------------------
Field BlockStructuredColumns::createField(const eckit::Configuration& options) const {
    Field field(structuredcolumns_->config_name(options), structuredcolumns_->config_datatype(options), config_spec(options));
    structuredcolumns_->set_field_metadata(options, field);
    field.set_functionspace(this);
    return field;
}

Field BlockStructuredColumns::createField(const Field& other, const eckit::Configuration& config) const {
    return createField(option::name(other.name()) | option::datatype(other.datatype()) |
                       option::levels(other.levels()) |option::variables(other.variables()) |
                       option::type(other.metadata().getString("type", "scalar")) | config);
}
// ----------------------------------------------------------------------------

// ----------------------------------------------------------------------------
// Scatter FieldSet
// ----------------------------------------------------------------------------
void BlockStructuredColumns::scatter(const FieldSet& global_fieldset, FieldSet& local_fieldset) const {
    ATLAS_ASSERT(local_fieldset.size() == global_fieldset.size());
    for (idx_t f = 0; f < local_fieldset.size(); ++f) {
        const Field& glb  = global_fieldset[f];
        Field& loc        = local_fieldset[f];
        auto sloc         = structuredcolumns_->createField(glb, util::Config("global",false));
        structuredcolumns_->scatter(glb, sloc);
        loc.metadata() = sloc.metadata();
        transpose_nonblocked_to_blocked(sloc, loc, *this);
    }
}

// ----------------------------------------------------------------------------
// Scatter Field
// ----------------------------------------------------------------------------
void BlockStructuredColumns::scatter(const Field& global, Field& local) const {
    FieldSet global_fields;
    FieldSet local_fields;
    global_fields.add(global);
    local_fields.add(local);
    scatter(global_fields, local_fields);
}

// ----------------------------------------------------------------------------
// Gather FieldSet
// ----------------------------------------------------------------------------
void BlockStructuredColumns::gather(const FieldSet& local_fieldset, FieldSet& global_fieldset) const {
    ATLAS_ASSERT(local_fieldset.size() == global_fieldset.size());
    for (idx_t f = 0; f < local_fieldset.size(); ++f) {
        const Field& loc = local_fieldset[f];
        Field& glb       = global_fieldset[f];
        auto sloc = structuredcolumns_->createField(loc, util::Config("global",false));
        transpose_blocked_to_nonblocked(loc, sloc, *this);
        structuredcolumns_->gather(sloc, glb);
        glb.metadata() = loc.metadata();
        glb.metadata().set("global", false);
    }
}
// ----------------------------------------------------------------------------

void BlockStructuredColumns::setup(const eckit::Configuration &config) {
    nproma_ = 1;
    idx_t tmp_nproma;
    if (config.get("nproma", tmp_nproma)) {
        ATLAS_ASSERT(tmp_nproma > 0);
        nproma_ = tmp_nproma;
    }

    nblks_ = std::floor( structuredcolumns_->size() / nproma_ );
    endblk_size_ = nproma_;
    if (structuredcolumns_->size() % nproma_ > 0) {
        endblk_size_ = structuredcolumns_->size() - nblks_ * nproma_;
        nblks_++;
    }
}

// ----------------------------------------------------------------------------
// Gather Field
// ----------------------------------------------------------------------------
void BlockStructuredColumns::gather(const Field& local, Field& global) const {
    FieldSet local_fields;
    FieldSet global_fields;
    local_fields.add(local);
    global_fields.add(global);
    gather(local_fields, global_fields);
}

// ----------------------------------------------------------------------------
// Checksum Field
// ----------------------------------------------------------------------------

std::string BlockStructuredColumns::checksum(const Field&) const {
    ATLAS_NOTIMPLEMENTED;
}

std::string BlockStructuredColumns::checksum(const FieldSet&) const {
    ATLAS_NOTIMPLEMENTED;
}


// ----------------------------------------------------------------------------


}  // namespace detail
}  // namespace functionspace
}  // namespace atlas
