const opcodes = require('./opcodes.js')

/**
 * Debug Interface
 * This expose some functions that can help with debugging wast
 */

module.exports = class DebugInterface {
  constructor (environment) {
    this.environment = environment
  }

  setModule (mod) {
    this.module = mod
  }

  get exportTable () {
    return {
      'print': function (a) {
        console.log(a)
      },
      'printMem': function (offset, length) {
        console.log(`<DEBUG(str): ${this.getMemoryBuffer(offset, length).toString()}>`)
      }.bind(this),

      'printMemHex': function (offset, length) {
        console.log(`<DEBUG(hex): ${this.getMemoryBuffer(offset, length).toString('hex')}>`)
      }.bind(this),

      'evmStackTrace': function (sp, op) {
        const opcode = opcodes(op)
        if (opcode.number) {
          opcode.name += opcode.number
        }
        console.error(`op: ${opcode.name} gas: ${this.environment.gasLeft}`)
        console.log('-------------stack--------------')
        for (let i = sp; i >= 0; i -= 32) {
          console.log(`${(sp - i) / 32} ${this.getMemoryBuffer(i).toString('hex')}`)
        }
        return sp
      }.bind(this)
    }
  }

  getMemoryBuffer (offset) {
    return new Buffer(this.module.exports.memory.slice(offset, offset + 32)).reverse()
  }
}