var stringify  = require('json-stringify-safe')
  , format     = require('util').format
  , is         = require('core-util-is')
  , individual = require('individual')('$$bole', { })
  , levels     = 'debug info warn error'.split(' ')
  , hostname   = require('os').hostname()
  , pid        = process.pid


function stackToString (e) {
  var s = e.stack
    , ce

  if (is.isFunction(e.cause) && (ce = e.cause()))
    s += '\nCaused by: ' + stackToString(ce)

  return s
}


function levelLogger (level, name) {
  return function (inp) {
    var outputs = individual[level]

    if (!outputs)
      return // no outputs for this level

    var out = {
            time     : new Date().toISOString()
          , hostname : hostname
          , pid      : pid
          , level    : level
          , name     : name
        }
      , k
      , i = 0
      , stringified

    if (is.isError(inp)) {
      if (arguments.length > 1)
        out.message = format.apply(null, Array.prototype.slice.call(arguments, 1))

      out.err = {
          name    : inp.name
        , message : inp.message
        , code    : inp.code // perhaps
        , stack   : stackToString(inp)
      }
    } else if (is.isObject(inp) && inp.method && inp.url && inp.headers && inp.socket) {
      if (arguments.length > 1)
        out.message = format.apply(null, Array.prototype.slice.call(arguments, 1))

      out.req = {
          method        : inp.method
        , url           : inp.url
        , headers       : inp.headers
        , remoteAddress : inp.connection.remoteAddress
        , remotePort    : inp.connection.remotePort
      }
    } else if (is.isObject(inp)) {
      if (arguments.length > 1)
        out.message = format.apply(null, Array.prototype.slice.call(arguments, 1))

      for (k in inp) {
        if (Object.prototype.hasOwnProperty.call(inp, k))
          out[k] = inp[k]
      }
    } else if (!is.isUndefined(inp)) {
      out.message = format.apply(null, arguments)
    }


    for (; i < outputs.length; i++) {
      if (outputs[i]._writableState && outputs[i]._writableState.objectMode === true) {
        outputs[i].write(out)
      } else {
        if (!stringified) // lazy stringify
          stringified = stringify(out) + '\n'
        outputs[i].write(stringified)
      }
    }
  }
}


function bole (name) {
  function boleLogger (subname) {
    return bole(name + ':' + subname)
  }

  function makeLogger (p, level) {
    p[level] = levelLogger(level, name)
    return p
  }

  return levels.reduce(makeLogger, boleLogger)
}


bole.output = function (opt) {
  if (Array.isArray(opt))
    return opt.forEach(bole.output)

  var i = 0
    , b = false

  for (; i < levels.length; i++) {
    if (levels[i] === opt.level)
      b = true

    if (b) {
      if (!individual[levels[i]])
        individual[levels[i]] = []
      individual[levels[i]].push(opt.stream)
    }
  }
}


bole.reset = function () {
  for (var k in individual)
    delete individual[k]
}


module.exports = bole