#include "circuit.h"

#include <queue>
#include <unordered_map>


void Circuit::init_stems() {
    for(auto& gate: gates) {
        if(gate->outputs.size() >= 2) {
            stems.push_back(gate);
        }
    }
    for(auto &gate :  PIs) {
        stems.push_back(gate);
    }
}

void Circuit::init_topo_index() {
    int topo = 1;
    std::queue<Gate*> q;

    std::unordered_map<Gate*, int> ins;
    for(Gate* gate : gates) {
        ins[gate] = gate->inputs.size();
    }

    for(auto in : PIs) {
        in->topo = topo++;
        q.push(in);
    }

    while(!q.empty()) {
        Gate* g = q.front(); q.pop();
        for(Gate* out : g->outputs) {
            ins[out]--;
            if(ins[out] == 0) {
                out->topo = topo++;
                q.push(out);
            }
        }
    }
}

int Circuit::cal_gate_value(const Gate* &gate) {
    int res;

    switch(gate->type) {
        case Gate::NOT:
            res = !gate->inputs[0]->value;
            break;
        case Gate::BUF:
            res = gate->inputs[0]->value;
            break;
        case Gate::AND:
            res = gate->inputs[0]->value;
            for(int i=1; i<gate->inputs.size(); i++) {
                res &= gate->inputs[i]->value;
            }
            break;
        case Gate::NAND:
            res = gate->inputs[0]->value;
            for(int i=1; i<gate->inputs.size(); i++) {
                res &= gate->inputs[i]->value;
            }
            res = !res;
            break;
        case Gate::OR:
            res = gate->inputs[0]->value;
            for(int i=1; i<gate->inputs.size(); i++) {
                res |= gate->inputs[i]->value;
            }
            break;
        case Gate::NOR:
            res = gate->inputs[0]->value;
            for(int i=1; i<gate->inputs.size(); i++) {
                res |= gate->inputs[i]->value;
            }
            res = !res;
            break;
        case Gate::XOR:
            res = gate->inputs[0]->value;
            for(int i=1; i<gate->inputs.size(); i++) {
                res ^= gate->inputs[i]->value;
            }
            break;
        case Gate::XNOR:
            res = gate->inputs[0]->value;
            for(int i=1; i<gate->inputs.size(); i++) {
                res ^= gate->inputs[i]->value;
            }
            res = !res;
            break;
    }
    return res;
}