/* 
 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
 * Click nbfs://nbhost/SystemFileSystem/Templates/ClientSide/javascript.js to edit this template
 */

/**
 * instrucoes iniciais para criacao da maquina de estado EVM
 * */


//instrucoes das operacoes a ser realizadas pelo smart contract
const STOP = "STOP",
      ADD  = "ADD",
      PUSH = "PUSH",
      SUB  = "SUB",
      MULT = "MULT",
      DIV  = "DIV",
      LT   = "LT",
      GT   = "GT",
      EQ   = "EQ",
      AND  = "AND",
      OR   = "OR",
      JUMP = "JUMP",
      JUMPI = "JUMPI",
      EXECUTION_COMPLETE = "execution_complete",
      EXECUTION_LIMIT = 10000;

class Interpreter {
    
    constructor() {
        this.state = {
            programCounter : 0,
            stack: [],
            code : [],
            executionCount: 0
        };
    }


    jump() {
        const destination = this.state.stack.pop();
        if(destination < 0 || destination > this.state.code.length) {
            throw new Error(`invalid destination: ${destination}`);
        }
        this.state.programCounter = destination;
        this.state.programCounter--;
    }

    runCode(code) {
        var a = 0,
            b = 0,
            c = 0,
            value = 0,
            opcode = null;
        this.state.code = code;
        
        console.log("\n\ndbg-iniciando runCode();");
        console.log("dbg-param-code=>" + code);
        console.log("dbg-param-length=>" + this.state.code.length);
        
        while(this.state.programCounter < this.state.code.length) {
            this.state.executionCount++;
            if(this.state.executionCount > EXECUTION_LIMIT) {
                throw new Error(`check for an infinite loop; Execution limit of ${EXECUTION_LIMIT}`);
            }
            const opcode = this.state.code[this.state.programCounter];
            console.log("dbg-while");
            console.log("dbg-programcounter=>"+this.state.programCounter);
            console.log("dbg-opcode=>"+opcode);
            
            try {
                switch (opcode) {

                    case PUSH:
                        console.log("dbg-case-push");
                        this.state.programCounter++;
                        if(this.state.programCounter === this.state.code.length) {
                            throw new Error("the push instruction canneot be least");
                        }
                        console.log("dbg-programcounter");
                        value = this.state.code[this.state.programCounter];
                        console.log("dbg-value=>"+value);
                        this.state.stack.push(value);
                    break;

                    case ADD:
                    case SUB:
                    case MULT:
                    case DIV:
                    case LT:
                    case GT:
                    case EQ:
                    case AND:
                    case OR:
                        console.log("dbg-case-multicase");
                        console.log("dbg-case-name=>" + opcode);
                        a = this.state.stack.pop();
                        b = this.state.stack.pop();

                        console.log("dbg-value-a=>" + a);
                        console.log("dbg-value-b=>" + b);
                        console.log("dbg-value-c=>" + c);

                        if(opcode === ADD) { 
                            c = (a + b); 
                            console.log("dbg-if-soma=>" + c);
                        };

                        if(opcode === SUB) { 
                            c = (a - b); 
                            console.log("dbg-if-subt5racao=>" + c);
                        };

                        if(opcode === MULT){ 
                            c = (a * b); 
                            console.log("dbg-if-multiplicacao=>" + c);
                        };

                        if(opcode === DIV) { 
                            c = (a / b); 
                            console.log("dbg-if-divisao=>" + c);
                        };

                        if(opcode === LT) { 
                            c = ((a < b) ? (1) : (0)); 
                            console.log("dbg-if-LT=>" + c);
                        };

                        if(opcode === GT) { 
                            c = ((a > b) ? (1) : (0)); 
                            console.log("dbg-if-GT=>" + c);
                        };

                        if(opcode === EQ) { 
                            c = ((a === b) ? (1) : (0)); 
                            console.log("dbg-if-EQ=>" + c);
                        };

                        if(opcode === AND) { 
                            c = (a && b); 
                            console.log("dbg-if-divisao=>" + c);
                        };

                        if(opcode === OR) { 
                            c = (a || b); 
                            console.log("dbg-if-divisao=>" + c);
                        };

                        this.state.stack.push(c);
                    break;

                    case JUMP:
                        this.jump();
                    break;

                    case JUMPI:
                        const condition = this.state.stack.pop();
                        if(condition) {
                            this.jump();
                        }
                    break;

                    case STOP:
                        console.log("dbg-case-stop");
                    throw new Error(EXECUTION_COMPLETE);
                    
                    default:
                        console.log("dbg-case-default");
                    break;
                }

            } catch (error) {
                if(error.message === EXECUTION_COMPLETE) {
                    return {
                        result: this.state.stack[this.state.stack.length-1]
                    }
                }
                console.log("dbg-catch-msg" + this.state.stack[this.state.stack.length - 1]);
                console.log("dbg-catch-err" + error);
                throw error;
//                return this.state.stack[this.state.stack.length - 1];
            }

            this.state.programCounter++;
        }
    }
    
}

console.log("resultado da soma", new Interpreter().runCode([PUSH, 10,PUSH, 5, ADD, STOP]));
console.log("resultado da SUBTRACAO", new Interpreter().runCode([PUSH, 1, PUSH, 5, SUB, STOP]));
console.log("resultado da DIVISAO", new Interpreter().runCode([PUSH, 2, PUSH, 3, DIV, STOP]));
console.log("resultado da MULTIPLICACAO", new Interpreter().runCode([PUSH, 2, PUSH, 3, MULT, STOP]));
console.log("resultado da LT", new Interpreter().runCode([PUSH, 2, PUSH, 3, LT, STOP]));
console.log("resultado da GT", new Interpreter().runCode([PUSH, 2, PUSH, 3, GT, STOP]));
console.log("resultado da EQ", new Interpreter().runCode([PUSH, 2, PUSH, 3, EQ, STOP]));
console.log("resultado da AND", new Interpreter().runCode([PUSH, 1, PUSH, 0, AND, STOP]));
console.log("resultado da OR", new Interpreter().runCode([PUSH, 1, PUSH, 0, OR, STOP]));
console.log("resultado da JUMP", new Interpreter().runCode([PUSH, 6,JUMP, PUSH, 0, "Jump successful", STOP]));
console.log("resultado da JUMPI", new Interpreter().runCode([PUSH, 8,PUSH, 1, JUMPI, PUSH, 0, "JumpI successful", STOP]));

try {
    new Interpreter().runCode([PUSH, 99, JUMP, PUSH, 0, JUMP, PUSH, "jump sucessful", STOP]);
} catch(error) {
    console.log("invalid destination error =>", error.message);
}

try {
    new Interpreter().runCode([PUSH, 0, PUSH]);
} catch (error) {
    console.log("expected invalid push error:", error.message);
}


try {
    new Interpreter().runCode([PUSH, 0, JUMP, STOP]);
} catch (error) {
    console.log("expected invalid execution error:", error.message);
}