#include <cstdio>
#include <cstring>
#include <unordered_set>
#include <unordered_map>
#include <fstream>
#include <stdlib.h>
using namespace std;

#include "vtr_assert.h"
#include "vtr_log.h"
#include "vtr_math.h"

#include "vpr_error.h"
#include "vpr_types.h"

#include "read_xml_arch_file.h"
#include "globals.h"
#include "atom_netlist.h"
#include "prepack.h"
#include "pack_types.h"
#include "pack.h"
#include "read_blif.h"
#include "cluster.h"
#include "SetupGrid.h"

#ifdef USE_HMETIS
#include "hmetis_graph_writer.h"
static vtr::vector<AtomBlockId, int> read_hmetis_graph(string &hmetis_output_file_name, const int num_parts);
//TODO: CHANGE THIS HARDCODING
static string hmetis("/cygdrive/c/Source/Repos/vtr-verilog-to-routing/vpr/hmetis-1.5-WIN32/shmetis.exe ");
#endif

/* #define DUMP_PB_GRAPH 1 */
/* #define DUMP_BLIF_INPUT 1 */

static std::unordered_set<AtomNetId> alloc_and_load_is_clock(bool global_clocks);
static bool try_size_device_grid(const t_arch& arch, const std::map<t_type_ptr,size_t>& num_type_instances, float target_device_utilization, std::string device_layout_name);
static t_ext_pin_util_targets parse_target_external_pin_util(std::vector<std::string> specs);
static std::string target_external_pin_util_to_string(const t_ext_pin_util_targets& ext_pin_utils);

bool try_pack(t_packer_opts *packer_opts,
        const t_arch * arch,
		const t_model *user_models,
        const t_model *library_models,
        float interc_delay,
        vector<t_lb_type_rr_node> *lb_type_rr_graphs
#ifdef ENABLE_CLASSIC_VPR_STA
        , t_timing_inf timing_inf
#endif
        ) {
    std::unordered_set<AtomNetId> is_clock;
    std::multimap<AtomBlockId,t_pack_molecule*> atom_molecules; //The molecules associated with each atom block
    std::unordered_map<AtomBlockId,t_pb_graph_node*> expected_lowest_cost_pb_gnode; //The molecules associated with each atom block
	const t_model *cur_model;
	int num_models;
	t_pack_patterns *list_of_packing_patterns;
	int num_packing_patterns;
	t_pack_molecule *list_of_pack_molecules, * cur_pack_molecule;
#ifdef USE_HMETIS
	vtr::vector<AtomBlockId,int> partitions;
#endif
	VTR_LOG("Begin packing '%s'.\n", packer_opts->blif_file_name.c_str());

	/* determine number of models in the architecture */
	num_models = 0;
	cur_model = user_models;
	while (cur_model) {
		num_models++;
		cur_model = cur_model->next;
	}
	cur_model = library_models;
	while (cur_model) {
		num_models++;
		cur_model = cur_model->next;
	}


	is_clock = alloc_and_load_is_clock(packer_opts->global_clocks);

    auto& atom_ctx = g_vpr_ctx.atom();

    size_t num_p_inputs = 0;
    size_t num_p_outputs = 0;
    for(auto blk_id : atom_ctx.nlist.blocks()) {
        auto type = atom_ctx.nlist.block_type(blk_id);
        if(type == AtomBlockType::INPAD) {
            ++num_p_inputs;
        } else if(type == AtomBlockType::OUTPAD) {
            ++num_p_outputs;
        }
    }

	VTR_LOG("\n");
	VTR_LOG("After removing unused inputs...\n");
	VTR_LOG("\ttotal blocks: %zu, total nets: %zu, total inputs: %zu, total outputs: %zu\n",
		atom_ctx.nlist.blocks().size(), atom_ctx.nlist.nets().size(), num_p_inputs, num_p_outputs);

	VTR_LOG("Begin prepacking.\n");
	list_of_packing_patterns = alloc_and_load_pack_patterns(&num_packing_patterns);
    list_of_pack_molecules = alloc_and_load_pack_molecules(list_of_packing_patterns,
                                atom_molecules,
                                expected_lowest_cost_pb_gnode,
                                num_packing_patterns);
	VTR_LOG("Finish prepacking.\n");

	if(packer_opts->auto_compute_inter_cluster_net_delay) {
		packer_opts->inter_cluster_net_delay = interc_delay;
		VTR_LOG("Using inter-cluster delay: %g\n", packer_opts->inter_cluster_net_delay);
	}

#ifdef USE_HMETIS
	if (!packer_opts->hmetis_input_file.empty()) {
		/*	hmetis.exe <GraphFile>			 <Nparts> <UBfactor> <Nruns> <Ctype> <RType> <VCycle> <Reconst> <dbglvl>
			  or
			hmetis.exe <GraphFile> <FixFile> <Nparts> <UBfactor> <Nruns> <Ctype> <RType> <VCycle> <Reconst> <dbglvl>
			 GraphFile: name of the hypergraph file
			 FixFile  : name of the file containing pre-assignment of vertices to partitions
			 Nparts   : number of partitions desired
			 UBfactor : balance between the partitions (e.g., use 5 for a 45-55 bisection balance)
			 Nruns    : Number of Iterations (shmetis defaults to 10)
			 CType    : HFC(1), FC(2), GFC(3), HEDGE(4), EDGE(5)
			 RType    : FM(1), 1WayFM(2), EEFM(3)
			 VCycle   : No(0), @End(1), ForMin(2), All(3)
			 Reconst  : NoReconstruct_HE(0), Reconstruct_HE (1)
			 dbglvl   : debug level*/

		VTR_LOG("Writing hmetis hypergraph to %s\n", packer_opts->hmetis_input_file);

		// Write AtomNetlist into hGraph format
		write_hmetis_graph(packer_opts->hmetis_input_file);

		// Set the rest of the arguments
		// For a reference to what the string arguments mean, refer to the manual

		// The number of partitions is determined in one of two methods:
		// 1. Partition tree would result in the size of subcircuits ~= 4 (Elias Vansteenkiste, et al.)
		// 2. Partition depth = 5, i.e. num_parts = 32 (Doris Chen, et al.)
		//int num_parts = atom_ctx.nlist.blocks().size() / 4; // Method 1.
		//TODO: Find an appropriate value (may be from packer_opts) for num_parts
		int num_parts = 32; //Method 2.

		string run_hmetis = hmetis + packer_opts->hmetis_input_file + " " + to_string(num_parts) + " 5";

		// Check if OS is Windows or Linux and run hMetis accordingly
		//TODO: USE HMETIS WITH ALL ARGUMENTS INSTEAD FOR FURTHER REFINEMENT
		//Using shmetis (standard hmetis) to simplify
		system(run_hmetis.c_str());

		/* Parse the output file from hMetis, contains |V| lines, ith line = partition of V_i.
		*  Store the results into a vector.
		*/
		string hmetis_output_file(packer_opts->hmetis_input_file + ".part." + to_string(num_parts));

		partitions = read_hmetis_graph(hmetis_output_file, num_parts);

		// Print each block's partition
		VTR_LOG("Partitioning complete\n");

		vector<vector<AtomBlockId>> print_partitions(num_parts);
		for (auto blk_id : atom_ctx.nlist.blocks()) {
			print_partitions[partitions[blk_id]].push_back(blk_id);
		}
		for (int i = 0; i < (int)print_partitions.size(); i++) {
			VTR_LOG("Blocks in partition %zu:\n\t", i);
			for (int j = 0; j < (int)print_partitions[i].size(); j++)
				VTR_LOG("%zu ", size_t(print_partitions[i][j]));
			VTR_LOG("\n");
		}
	}
#endif

    t_ext_pin_util_targets target_external_pin_util = parse_target_external_pin_util(packer_opts->target_external_pin_util);

    VTR_LOG("Packing with pin utilization targets: %s\n", target_external_pin_util_to_string(target_external_pin_util).c_str());


    bool allow_unrelated_clustering = false;
    if (packer_opts->allow_unrelated_clustering == e_unrelated_clustering::ON) {
        allow_unrelated_clustering = true;
    } else if (packer_opts->allow_unrelated_clustering == e_unrelated_clustering::OFF) {
        allow_unrelated_clustering = false;
    }
    int pack_iteration = 1;

    while (true) {

        //Cluster the netlist
        auto num_type_instances = do_clustering(*packer_opts, arch, list_of_pack_molecules, num_models,
                                    is_clock,
                                    atom_molecules,
                                    expected_lowest_cost_pb_gnode,
                                    allow_unrelated_clustering,
                                    lb_type_rr_graphs,
                                    target_external_pin_util
#ifdef USE_HMETIS
                                    , partitions
#endif
#ifdef ENABLE_CLASSIC_VPR_STA
                                    , timing_inf
#endif
                                    );

        //Try to size/find a device
        bool fits_on_device = try_size_device_grid(*arch, num_type_instances, packer_opts->target_device_utilization, packer_opts->device_layout);

        if (fits_on_device) {
            break; //Done
        } else if (pack_iteration == 1 && packer_opts->allow_unrelated_clustering == e_unrelated_clustering::AUTO) {
            //1st pack attempt was unsucessful (i.e. not dense enough) and we have control of unrelated clustering
            //
            //Turn it on to increase packing density
            VTR_ASSERT(allow_unrelated_clustering == false);
            allow_unrelated_clustering = true;
            VTR_LOG("Packing failed to fit on device. Re-packing with: unrelated_logic_clustering=%s\n", (allow_unrelated_clustering ? "true" : "false"));
        } else {
            //Unable to pack densely enough: Give Up


            //No suitable device found
            std::string resource_reqs;
            std::string resource_avail;
            auto& grid = g_vpr_ctx.device().grid;
            for (auto iter = num_type_instances.begin(); iter != num_type_instances.end(); ++iter) {
                if (iter != num_type_instances.begin()) {
                    resource_reqs += ", ";
                    resource_avail += ", ";
                }

                resource_reqs += std::string(iter->first->name) + ": " + std::to_string(iter->second);
                resource_avail += std::string(iter->first->name) + ": " + std::to_string(grid.num_instances(iter->first));
            }

            VPR_THROW(VPR_ERROR_OTHER, "Failed to find device which satisifies resource requirements required: %s (available %s)", resource_reqs.c_str(), resource_avail.c_str());
        }

        //Reset clustering for re-packing
        g_vpr_ctx.mutable_clustering().clb_nlist = ClusteredNetlist();
        for (auto blk : g_vpr_ctx.atom().nlist.blocks()) {
            g_vpr_ctx.mutable_atom().lookup.set_atom_clb(blk, ClusterBlockId::INVALID());
            g_vpr_ctx.mutable_atom().lookup.set_atom_pb(blk, nullptr);
        }
        for (auto net : g_vpr_ctx.atom().nlist.nets()) {
            g_vpr_ctx.mutable_atom().lookup.set_atom_clb_net(net, ClusterNetId::INVALID());
        }

        ++pack_iteration;
    }

	/*free list_of_pack_molecules*/
	free_list_of_pack_patterns(list_of_packing_patterns, num_packing_patterns);

	cur_pack_molecule = list_of_pack_molecules;
	while (cur_pack_molecule != nullptr){
		cur_pack_molecule = list_of_pack_molecules->next;
		delete list_of_pack_molecules;
		list_of_pack_molecules = cur_pack_molecule;
	}

	VTR_LOG("\n");
	VTR_LOG("Netlist conversion complete.\n");
	VTR_LOG("\n");

    return true;
}

float get_arch_switch_info(short switch_index, int switch_fanin, float &Tdel_switch, float &R_switch, float &Cout_switch){
	/* Fetches delay, resistance and output capacitance of the architecture switch at switch_index.
	Returns the total delay through the switch. Used to calculate inter-cluster net delay. */

	/* The intrinsic delay may depend on fanin to the switch. If the delay map of a
	   switch from the architecture file has multiple (#inputs, delay) entries, we
	   interpolate/extrapolate to get the delay at 'switch_fanin'. */
    auto& device_ctx = g_vpr_ctx.device();

    Tdel_switch = device_ctx.arch_switch_inf[switch_index].Tdel(switch_fanin);
	R_switch = device_ctx.arch_switch_inf[switch_index].R;
	Cout_switch = device_ctx.arch_switch_inf[switch_index].Cout;

	/* The delay through a loaded switch is its intrinsic (unloaded)
	delay plus the product of its resistance and output capacitance. */
	return Tdel_switch + R_switch * Cout_switch;
}

std::unordered_set<AtomNetId> alloc_and_load_is_clock(bool global_clocks) {

	/* Looks through all the atom blocks to find and mark all the clocks, by setting
	 * the corresponding entry by adding the clock to is_clock.
     * global_clocks is used
	 * only for an error check.                                                */

	int num_clocks = 0;
    std::unordered_set<AtomNetId> is_clock;

	/* Want to identify all the clock nets.  */
    auto& atom_ctx = g_vpr_ctx.atom();

    for(auto blk_id : atom_ctx.nlist.blocks()) {
        for(auto pin_id : atom_ctx.nlist.block_clock_pins(blk_id)) {
            auto net_id = atom_ctx.nlist.pin_net(pin_id);
            if (!is_clock.count(net_id)) {
                is_clock.insert(net_id);
                num_clocks++;
            }
        }
	}

	/* If we have multiple clocks and we're supposed to declare them global, *
	 * print a warning message, since it looks like this circuit may have    *
	 * locally generated clocks.                                             */

	if (num_clocks > 1 && global_clocks) {
		VTR_LOG_WARN(
				"All %d clocks will be treated as global.\n", num_clocks);
	}

	return (is_clock);
}

#ifdef USE_HMETIS
/* Reads in the output of the hMetis partitioner and returns
*  A 2-D vector that contains all the blocks in each partition
*/
static vtr::vector<AtomBlockId, int> read_hmetis_graph(string &hmetis_output_file, const int num_parts) {
	ifstream fp(hmetis_output_file.c_str());
	vtr::vector<AtomBlockId, int> partitions;
	string line;
	int block_num = 0; //Indexing for CLB's start at 0

	// Check that # of lines in output file matches # of blocks/vertices
	auto& atom_ctx = g_vpr_ctx.atom();
	VTR_ASSERT((int)atom_ctx.nlist.blocks().size() == count(istreambuf_iterator<char>(fp), istreambuf_iterator<char>(), '\n'));

	partitions.resize(atom_ctx.nlist.blocks().size());

	// Reset the filestream to the beginning and reread
	fp.clear();
	fp.seekg(0, fp.beg);

	while (getline(fp, line)) {
		if (stoi(line) >= num_parts) {
			vpr_throw(VPR_ERROR_OTHER, __FILE__, __LINE__,
				"Partition for line '%s' exceeds the set number of partitions %d" , line, num_parts);
		}

		partitions[AtomBlockId(block_num)] = stoi(line);
		block_num++;
	}

	fp.close();

	return partitions;
}
#endif

static bool try_size_device_grid(const t_arch& arch, const std::map<t_type_ptr,size_t>& num_type_instances, float target_device_utilization, std::string device_layout_name) {
    auto& device_ctx = g_vpr_ctx.mutable_device();

    //Build the device
    auto grid = create_device_grid(device_layout_name, arch.grid_layouts, num_type_instances, target_device_utilization);

    /*
     *Report on the device
     */
    VTR_LOG("FPGA sized to %zu x %zu (%s)\n", grid.width(), grid.height(), grid.name().c_str());

    bool fits_on_device = true;

    float device_utilization = calculate_device_utilization(grid, num_type_instances);
    VTR_LOG("Device Utilization: %.2f (target %.2f)\n", device_utilization, target_device_utilization);
    std::map<t_type_ptr,float> type_util;
    for (int i = 0; i < device_ctx.num_block_types; ++i) {
        auto type = &device_ctx.block_types[i];
        auto itr = num_type_instances.find(type);
        if (itr == num_type_instances.end()) continue;

        float num_instances = itr->second;
        float util = 0.;
        if (num_instances != 0) {
            util = num_instances / device_ctx.grid.num_instances(type);
        }
        type_util[type] = util;

        if (util > 1.) {
            fits_on_device = false;
        }
        VTR_LOG("\tBlock Utilization: %.2f Type: %s\n", util, type->name);
    }
    VTR_LOG("\n");

    return fits_on_device;
}

static t_ext_pin_util_targets parse_target_external_pin_util(std::vector<std::string> specs) {

    t_ext_pin_util_targets targets (1., 1.);

    if (specs.size() == 1 && specs[0] == "auto") {
        //No user-specified pin utilizations, infer them automatically.
        //
        //We set a pin utilization target based on the block type, with
        //the logic block having a lower utilization target and other blocks
        //(e.g. hard blocks) having no limit.

        auto& device_ctx = g_vpr_ctx.device();
        auto& grid = device_ctx.grid;
        t_type_ptr logic_block_type = infer_logic_block_type(grid);

        //Allowing 100% pin utilization of the logic block type can harm
        //routability, since it may allow a few (typically outlier) clusters to
        //use a very large number of pins -- causing routability issues. These
        //clusters can cause failed routings where only a handful of routing
        //resource nodes remain overused (and do not resolve) These can be
        //avoided by putting a (soft) limit on the number of input pins which
        //can be used, effectively clipping off the most egregeous outliers.
        //
        //Experiments show that limiting input utilization produces better quality 
        //than limiting output utilization (limiting input utilization implicitly 
        //also limits output utilization).
        //
        //For relatively high pin utilizations (e.g. > 70%) this has little-to-no
        //impact on the number of clusters required. As a result we set a default 
        //input pin utilization target which is high, but less than 100%.
        constexpr float LOGIC_BLOCK_TYPE_AUTO_INPUT_UTIL = 0.8;
        constexpr float LOGIC_BLOCK_TYPE_AUTO_OUTPUT_UTIL = 1.0;

        t_ext_pin_util logic_block_ext_pin_util(LOGIC_BLOCK_TYPE_AUTO_INPUT_UTIL , LOGIC_BLOCK_TYPE_AUTO_OUTPUT_UTIL);

        targets.set_block_pin_util(logic_block_type->name, logic_block_ext_pin_util);

    } else {
        //Process user specified overrides

        bool default_set = false;
        std::set<std::string> seen_block_types;

        for (auto spec : specs) {
            t_ext_pin_util target_ext_pin_util(1., 1.);

            auto block_values = vtr::split(spec, ":");
            std::string block_type;
            std::string values;
            if (block_values.size() == 2) {
                block_type = block_values[0];
                values = block_values[1];
            } else if (block_values.size() == 1) {
                values = block_values[0];
            } else {
                std::stringstream msg;
                msg << "In valid block pin utilization specification '" << spec << "' (expected at most one ':' between block name and values";
                VPR_THROW(VPR_ERROR_PACK, msg.str().c_str());
            }

            auto elements = vtr::split(values, ",");
            if (elements.size() == 1) {
                target_ext_pin_util.input_pin_util = vtr::atof(elements[0]);
            } else if (elements.size() == 2) {
                target_ext_pin_util.input_pin_util = vtr::atof(elements[0]);
                target_ext_pin_util.output_pin_util = vtr::atof(elements[1]);
            } else {
                std::stringstream msg;
                msg << "Invalid conversion from '" << spec << "' to external pin util (expected either a single float value, or two float values separted by a comma)";
                VPR_THROW(VPR_ERROR_PACK, msg.str().c_str());
            }

            if (target_ext_pin_util.input_pin_util < 0. || target_ext_pin_util.input_pin_util > 1.) {
                std::stringstream msg;
                msg << "Out of range target input pin utilization '" << target_ext_pin_util.input_pin_util << "' (expected within range [0.0, 1.0])";
                VPR_THROW(VPR_ERROR_PACK, msg.str().c_str());
            }
            if (target_ext_pin_util.output_pin_util < 0. || target_ext_pin_util.output_pin_util > 1.) {
                std::stringstream msg;
                msg << "Out of range target output pin utilization '" << target_ext_pin_util.output_pin_util << "' (expected within range [0.0, 1.0])";
                VPR_THROW(VPR_ERROR_PACK, msg.str().c_str());
            }

            if (block_type.empty()) {
                //Default value
                if (default_set) {
                    std::stringstream msg;
                    msg << "Only one default pin utilization should be specified";
                    VPR_THROW(VPR_ERROR_PACK, msg.str().c_str());
                }
                targets.set_default_pin_util(target_ext_pin_util);
                default_set = true;
            } else {
                if (seen_block_types.count(block_type)) {
                    std::stringstream msg;
                    msg << "Only one pin utilization should be specified for block type '" << block_type << "'";
                    VPR_THROW(VPR_ERROR_PACK, msg.str().c_str());
                }

                targets.set_block_pin_util(block_type, target_ext_pin_util);
                seen_block_types.insert(block_type);
            }
        }
    }

    return targets;
}

static std::string target_external_pin_util_to_string(const t_ext_pin_util_targets& ext_pin_utils) {
    std::stringstream ss;

    auto& device_ctx = g_vpr_ctx.device();

    for (int itype = 0; itype < device_ctx.num_block_types; ++itype) {

        if (is_empty_type(&device_ctx.block_types[itype])) continue;

        auto blk_name = device_ctx.block_types[itype].name;

        ss << blk_name << ":";

        auto pin_util = ext_pin_utils.get_pin_util(blk_name);
        ss << pin_util.input_pin_util << ',' << pin_util.output_pin_util;

        if (itype != device_ctx.num_block_types - 1) {
            ss << " ";
        }
    }

    return ss.str();
}