/*
 *  nextpnr -- Next Generation Place and Route
 *
 *  Copyright (C) 2018  gatecat <gatecat@ds0.me>
 *  Copyright (C) 2022  YRabbit <rabbit@yrabbit.cyou>
 *
 *  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 "globals.h"
#include <algorithm>
#include <iomanip>
#include <iostream>
#include <queue>
#include "cells.h"
#include "log.h"
#include "nextpnr.h"
#include "place_common.h"
#include "util.h"

NEXTPNR_NAMESPACE_BEGIN

class GowinGlobalRouter
{
  public:
    GowinGlobalRouter(Context *ctx) : ctx(ctx){};

  private:
    // wire -> clock#
    dict<WireId, int> used_wires;

    // ordered nets
    struct onet_t
    {
        IdString name;
        int clock_ports;
        WireId clock_io_wire; // IO wire if there is one

        onet_t() : name(IdString()), clock_ports(0), clock_io_wire(WireId()) {}
        onet_t(IdString _name) : name(_name), clock_ports(0), clock_io_wire(WireId()) {}

        // sort
        bool operator<(const onet_t &other) const
        {
            if ((clock_io_wire != WireId()) ^ (other.clock_io_wire != WireId())) {
                return !(clock_io_wire != WireId());
            }
            return clock_ports < other.clock_ports;
        }
        // search
        bool operator==(const onet_t &other) const { return name == other.name; }
    };

    bool is_clock_port(PortRef const &user)
    {
        if ((user.cell->type == id_SLICE || user.cell->type == id_ODDR || user.cell->type == id_ODDRC) && user.port == id_CLK) {
            return true;
        }
        return false;
    }

    WireId clock_io(PortRef const &driver)
    {
        // XXX normally all alternative functions of the pins should be passed
        // in the chip database, but at the moment we find them from aliases/pips
        // XXX check diff inputs too
        if (driver.cell == nullptr || driver.cell->bel == BelId()) {
            return WireId();
        }
        // clock IOs have pips output->SPINExx
        BelInfo &bel = ctx->bel_info(driver.cell->bel);
        if (bel.type != id_IOB) {
            return WireId();
        }
        WireId wire = bel.pins[id_O].wire;
        for (auto const pip : ctx->getPipsDownhill(wire)) {
            if (ctx->wire_info(ctx->getPipDstWire(pip)).type.str(ctx).rfind("SPINE", 0) == 0) {
                return wire;
            }
        }
        return WireId();
    }

    // gather the clock nets
    void gather_clock_nets(std::vector<onet_t> &clock_nets)
    {
        for (auto const &net : ctx->nets) {
            NetInfo const *ni = net.second.get();
            auto new_clock = clock_nets.end();
            WireId clock_wire = clock_io(ni->driver);
            if (clock_wire != WireId()) {
                clock_nets.emplace_back(net.first);
                new_clock = --clock_nets.end();
                new_clock->clock_io_wire = clock_wire;
            }
            for (auto const &user : ni->users) {
                if (is_clock_port(user)) {
                    if (new_clock == clock_nets.end()) {
                        clock_nets.emplace_back(net.first);
                        new_clock = --clock_nets.end();
                    }
                    ++(new_clock->clock_ports);
                }
            }
        }
        // need to prioritize the nets
        std::sort(clock_nets.begin(), clock_nets.end());

        if (ctx->verbose) {
            for (auto const &net : clock_nets) {
                log_info("  Net:%s, ports:%d, io:%s\n", net.name.c_str(ctx), net.clock_ports,
                         net.clock_io_wire == WireId() ? "No" : net.clock_io_wire.c_str(ctx));
            }
        }
    }

    // non clock port
    // returns GB pip
    IdString route_to_non_clock_port(WireId const dstWire, int clock, pool<IdString> &used_pips,
                                     pool<IdString> &undo_wires)
    {
        static std::vector<IdString> one_hop = {id_S111, id_S121, id_N111, id_N121, id_W111, id_W121, id_E111, id_E121};
        char buf[40];
        // uphill pips
        for (auto const uphill : ctx->getPipsUphill(dstWire)) {
            WireId srcWire = ctx->getPipSrcWire(uphill);
            if (find(one_hop.begin(), one_hop.end(), ctx->wire_info(ctx->getPipSrcWire(uphill)).type) !=
                one_hop.end()) {
                // found one hop pip
                if (used_wires.count(srcWire)) {
                    if (used_wires[srcWire] != clock) {
                        continue;
                    }
                }
                WireInfo wi = ctx->wire_info(srcWire);
                std::string wire_alias = srcWire.str(ctx).substr(srcWire.str(ctx).rfind("_") + 1);
                snprintf(buf, sizeof(buf), "R%dC%d_GB%d0_%s", wi.y + 1, wi.x + 1, clock, wire_alias.c_str());
                IdString gb = ctx->id(buf);
                auto up_pips = ctx->getPipsUphill(srcWire);
                if (find(up_pips.begin(), up_pips.end(), gb) != up_pips.end()) {
                    if (!used_wires.count(srcWire)) {
                        used_wires.insert(std::make_pair(srcWire, clock));
                        undo_wires.insert(srcWire);
                    }
                    used_pips.insert(uphill);
                    if (ctx->verbose) {
                        log_info("    1-hop Pip:%s\n", uphill.c_str(ctx));
                    }
                    return gb;
                }
            }
        }
        return IdString();
    }

    // route one net
    void route_net(onet_t const &net, int clock)
    {
        // For failed routing undo
        pool<IdString> used_pips;
        pool<IdString> undo_wires;

        log_info("  Route net %s, use clock #%d.\n", net.name.c_str(ctx), clock);
        for (auto const &user : ctx->net_info(net.name).users) {
            // >>> port <- GB<clock>0
            WireId dstWire = ctx->getNetinfoSinkWire(&ctx->net_info(net.name), user, 0);
            if (ctx->verbose) {
                log_info("   Cell:%s, port:%s, wire:%s\n", user.cell->name.c_str(ctx), user.port.c_str(ctx),
                         dstWire.c_str(ctx));
            }

            char buf[30];
            PipId gb_pip_id;
            if (user.port == id_CLK) {
                WireInfo const wi = ctx->wire_info(dstWire);
                snprintf(buf, sizeof(buf), "R%dC%d_GB%d0_%s", wi.y + 1, wi.x + 1, clock,
                         ctx->wire_info(dstWire).type.c_str(ctx));
                gb_pip_id = ctx->id(buf);
                // sanity
                NPNR_ASSERT(find(ctx->getPipsUphill(dstWire).begin(), ctx->getPipsUphill(dstWire).end(), gb_pip_id) !=
                            ctx->getPipsUphill(dstWire).end());
            } else {
                // Non clock port
                gb_pip_id = route_to_non_clock_port(dstWire, clock, used_pips, undo_wires);
                if (gb_pip_id == IdString()) {
                    if (ctx->verbose) {
                        log_info("  Can't find route to %s, net %s will be routed in a standard way.\n",
                                 dstWire.c_str(ctx), net.name.c_str(ctx));
                    }
                    for (IdString const undo : undo_wires) {
                        used_wires.erase(undo);
                    }
                    return;
                }
            }
            if (ctx->verbose) {
                log_info("    GB Pip:%s\n", gb_pip_id.c_str(ctx));
            }

            if (used_pips.count(gb_pip_id)) {
                if (ctx->verbose) {
                    log_info("    ^routed already^\n");
                }
                continue;
            }
            used_pips.insert(gb_pip_id);

            // >>> GBOx <- GTx0
            dstWire = ctx->getPipSrcWire(gb_pip_id);
            WireInfo dstWireInfo = ctx->wire_info(dstWire);
            int branch_tap_idx = clock > 3 ? 1 : 0;
            snprintf(buf, sizeof(buf), "R%dC%d_GT%d0_GBO%d", dstWireInfo.y + 1, dstWireInfo.x + 1, branch_tap_idx,
                     branch_tap_idx);
            PipId gt_pip_id = ctx->id(buf);
            if (ctx->verbose) {
                log_info("     GT Pip:%s\n", buf);
            }
            // sanity
            NPNR_ASSERT(find(ctx->getPipsUphill(dstWire).begin(), ctx->getPipsUphill(dstWire).end(), gt_pip_id) !=
                        ctx->getPipsUphill(dstWire).end());
            // if already routed
            if (used_pips.count(gt_pip_id)) {
                if (ctx->verbose) {
                    log_info("     ^routed already^\n");
                }
                continue;
            }
            used_pips.insert(gt_pip_id);

            // >>> GTx0 <- SPINExx
            // XXX no optimization here, we need to store
            // the SPINE <-> clock# correspondence in the database. In the
            // meantime, we define in run-time in a completely suboptimal way.
            std::vector<std::string> clock_spine;
            dstWire = ctx->getPipSrcWire(gt_pip_id);
            for (auto const uphill_pip : ctx->getPipsUphill(dstWire)) {
                std::string name = ctx->wire_info(ctx->getPipSrcWire(uphill_pip)).type.str(ctx);
                if (name.rfind("SPINE", 0) == 0) {
                    clock_spine.push_back(name);
                }
            }
            sort(clock_spine.begin(), clock_spine.end(), [](const std::string &a, const std::string &b) -> bool {
                return (a.size() < b.size()) || (a.size() == b.size() && a < b);
            });
            dstWireInfo = ctx->wire_info(dstWire);
            snprintf(buf, sizeof(buf), "R%dC%d_%s_GT%d0", dstWireInfo.y + 1, dstWireInfo.x + 1,
                     clock_spine[clock - branch_tap_idx * 4].c_str(), branch_tap_idx);
            PipId spine_pip_id = ctx->id(buf);
            if (ctx->verbose) {
                log_info("      Spine Pip:%s\n", buf);
            }
            // sanity
            NPNR_ASSERT(find(ctx->getPipsUphill(dstWire).begin(), ctx->getPipsUphill(dstWire).end(), spine_pip_id) !=
                        ctx->getPipsUphill(dstWire).end());
            // if already routed
            if (used_pips.count(spine_pip_id)) {
                if (ctx->verbose) {
                    log_info("      ^routed already^\n");
                }
                continue;
            }
            used_pips.insert(spine_pip_id);

            // >>> SPINExx <- IO
            dstWire = ctx->getPipSrcWire(spine_pip_id);
            dstWireInfo = ctx->wire_info(dstWire);
            PipId io_pip_id = PipId();
            for (auto const uphill_pip : ctx->getPipsUphill(dstWire)) {
                if (ctx->getPipSrcWire(uphill_pip) == net.clock_io_wire) {
                    io_pip_id = uphill_pip;
                }
            }
            NPNR_ASSERT(io_pip_id != PipId());
            if (ctx->verbose) {
                log_info("       IO Pip:%s\n", io_pip_id.c_str(ctx));
            }
            // if already routed
            if (used_pips.count(io_pip_id)) {
                if (ctx->verbose) {
                    log_info("      ^routed already^\n");
                }
                continue;
            }
            used_pips.insert(io_pip_id);
        }
        log_info("  Net %s is routed.\n", net.name.c_str(ctx));
        for (auto const pip : used_pips) {
            ctx->bindPip(pip, &ctx->net_info(net.name), STRENGTH_LOCKED);
        }
        ctx->bindWire(net.clock_io_wire, &ctx->net_info(net.name), STRENGTH_LOCKED);
    }

  public:
    Context *ctx;
    void route_globals()
    {
        log_info("Routing globals...\n");

        std::vector<onet_t> clock_nets;
        gather_clock_nets(clock_nets);
        // XXX we need to use the list of indexes of clocks from the database
        // use 6 clocks (XXX 3 for GW1NZ-1)
        int max_clock = 3, cur_clock = -1;
        for (auto const &net : clock_nets) {
            // XXX only IO clock for now
            if (net.clock_io_wire == WireId()) {
                log_info(" Non IO clock, skip %s.\n", net.name.c_str(ctx));
                continue;
            }
            if (++cur_clock >= max_clock) {
                log_info(" No more clock wires left, skip the remaining nets.\n");
                break;
            }
            route_net(net, cur_clock);
        }
    }
};

void route_gowin_globals(Context *ctx)
{
    GowinGlobalRouter router(ctx);
    router.route_globals();
}

NEXTPNR_NAMESPACE_END