const Viz = require('viz.js');
const fs = require('fs');

class GraphGenerator {
    constructor(engine) {
        this.engine = engine;
    }

    generate() {
        let id = 0;
        let contractString = "";
        let relationshipString = "";
        let idMapping = {};
        let contractInheritance = {};

        
        for (let contract in this.engine.contractsManager.contracts) {
            id++;

            idMapping[contract] = id;

            let contractLabel = "";

            contractLabel += `${contract}`;

            if(this.engine.contractsManager.contracts[contract].instanceOf !== undefined &&
               this.engine.contractsManager.contracts[this.engine.contractsManager.contracts[contract].instanceOf] !== undefined){
                contractInheritance[contract] = this.engine.contractsManager.contracts[contract].instanceOf;
            }

            contractLabel += "|";

            for(let i = 0; i < this.engine.contractsManager.contracts[contract].abiDefinition.length; i++){
                switch(this.engine.contractsManager.contracts[contract].abiDefinition[i].type){
                    case 'fallback': 
                        contractLabel += "«fallback»()" + '\\l';
                        break;
                    case 'constructor':
                        contractLabel += "«constructor»(";
                        for(let j = 0; j < this.engine.contractsManager.contracts[contract].abiDefinition[i].inputs.length; j++){
                            contractLabel += (j == 0 ? "" : ", ") + this.engine.contractsManager.contracts[contract].abiDefinition[i].inputs[j].type;
                        }
                        contractLabel += ")\\l";
                        break;
                    default: break;
                }       
            }

            let fHashes = this.engine.contractsManager.contracts[contract].functionHashes;
            if(fHashes != {} && fHashes != undefined){
                for(let method in this.engine.contractsManager.contracts[contract].functionHashes){
                    contractLabel += method + '\\l';
                }
            }
          

            contractString += `${id}[label = "{${contractLabel}}"]`
            contractString += "\n";
        }

        for (let c in this.engine.contractsManager.contractDependencies){
            let contractDependencies = Array.from(new Set(this.engine.contractsManager.contractDependencies[c]));
            contractDependencies.forEach(function(d){
                if(idMapping[c] !== undefined && idMapping[d] !== undefined){
                    relationshipString += `${idMapping[d]}->${idMapping[c]}[constraint=true, arrowtail=diamond]`
                    relationshipString += "\n";
                }
            });
        }

        for (let c in contractInheritance){
            relationshipString += `${idMapping[contractInheritance[c]]}->${idMapping[c]}`
            relationshipString += "\n";
        }


        let dot = `
        digraph hierarchy {
        node[shape=record,style=filled,fillcolor=gray95]
        edge[dir=back, arrowtail=empty]
            ${contractString}
            ${relationshipString}
        }`;

        let svg = Viz(dot);
        
        let filename = "diagram.svg";

        fs.writeFileSync(filename, svg, (err) => {
            if (err) throw err;
        });


    }
}

module.exports = GraphGenerator;