/*
 *  nextpnr -- Next Generation Place and Route
 *
 *  Copyright (C) 2018  David Shah <david@symbioticeda.com>
 *
 *  Permission to use, copy, modify, and/or distribute this software for any
 *  purpose with or without fee is hereby granted, provided that the above
 *  copyright notice and this permission notice appear in all copies.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

#include <algorithm>
#include <iterator>
#include <unordered_set>
#include "design_utils.h"
#include "log.h"
#include "util.h"

NEXTPNR_NAMESPACE_BEGIN

static bool is_nextpnr_iob(Context *ctx, CellInfo *cell)
{
    return cell->type == ctx->id("$nextpnr_ibuf") || cell->type == ctx->id("$nextpnr_obuf") ||
           cell->type == ctx->id("$nextpnr_iobuf");
}

static bool is_trellis_io(const Context *ctx, const CellInfo *cell) { return cell->type == ctx->id("TRELLIS_IO"); }

// Simple "packer" to remove nextpnr IOBUFs, this assumes IOBUFs are manually instantiated
void pack_io(Context *ctx)
{
    std::unordered_set<IdString> packed_cells;
    std::vector<std::unique_ptr<CellInfo>> new_cells;
    log_info("Packing IOs..\n");

    for (auto cell : sorted(ctx->cells)) {
        CellInfo *ci = cell.second;
        if (is_nextpnr_iob(ctx, ci)) {
            CellInfo *trio = nullptr;
            if (ci->type == ctx->id("$nextpnr_ibuf") || ci->type == ctx->id("$nextpnr_iobuf")) {
                trio = net_only_drives(ctx, ci->ports.at(ctx->id("O")).net, is_trellis_io, ctx->id("B"), true, ci);

            } else if (ci->type == ctx->id("$nextpnr_obuf")) {
                trio = net_only_drives(ctx, ci->ports.at(ctx->id("I")).net, is_trellis_io, ctx->id("B"), true, ci);
            }
            if (trio != nullptr) {
                // Trivial case, TRELLIS_IO used. Just destroy the net and the
                // iobuf
                log_info("%s feeds TRELLIS_IO %s, removing %s %s.\n", ci->name.c_str(ctx), trio->name.c_str(ctx),
                         ci->type.c_str(ctx), ci->name.c_str(ctx));
                NetInfo *net = trio->ports.at(ctx->id("B")).net;
                if (net != nullptr) {
                    ctx->nets.erase(net->name);
                    trio->ports.at(ctx->id("B")).net = nullptr;
                }
                if (ci->type == ctx->id("$nextpnr_iobuf")) {
                    NetInfo *net2 = ci->ports.at(ctx->id("I")).net;
                    if (net2 != nullptr) {
                        ctx->nets.erase(net2->name);
                    }
                }
            } else {
                log_error("TRELLIS_IO required on all top level IOs...\n");
            }
            packed_cells.insert(ci->name);
            std::copy(ci->attrs.begin(), ci->attrs.end(), std::inserter(trio->attrs, trio->attrs.begin()));
        }
    }
    for (auto pcell : packed_cells) {
        ctx->cells.erase(pcell);
    }
    for (auto &ncell : new_cells) {
        ctx->cells[ncell->name] = std::move(ncell);
    }
}

// Main pack function
bool Arch::pack()
{
    Context *ctx = getCtx();
    try {
        log_break();
        pack_io(ctx);
        log_info("Checksum: 0x%08x\n", ctx->checksum());
        return true;
    } catch (log_execution_error_exception) {
        return false;
    }
}

NEXTPNR_NAMESPACE_END