var log = require('bole')('budo')
var onResHeaders = require('on-headers')
var onResFinished = require('on-finished')

module.exports = simpleHttpLoggerMiddleware
function simpleHttpLoggerMiddleware (opts) {
  opts = opts || {}

  var httpLogger = function simpleHttpLogger (req, res, next) {
    if (httpLogger.ignores.indexOf(req.url) >= 0) return next()
    if (!req.url) return next()

    // request data
    req._startAt = undefined

    // response data
    res._startAt = undefined

    // record request start
    recordStartTime.call(req)

    var byteLength = 0
    var logRequest = function () {
      if (!req._startAt || !res._startAt) {
        // missing request and/or response start time
        return
      }

      // calculate diff
      var ms = (res._startAt[0] - req._startAt[0]) * 1000 +
        (res._startAt[1] - req._startAt[1]) * 1e-6

      log.info({
        elapsed: ms,
        contentLength: byteLength,
        method: (req.method || 'GET').toUpperCase(),
        url: req.url,
        statusCode: res.statusCode,
        type: httpLogger.type === 'static' ? undefined : httpLogger.type,
        colors: {
          elapsed: ms > 1000 ? 'yellow' : 'dim'
        }
      })
    }

    var isAlreadyLogging = res._simpleHttpLogger
    res._simpleHttpLogger = true

    if (!isAlreadyLogging) {
      // record response start
      onResHeaders(res, recordStartTime)

      // log when response finished
      onResFinished(res, logRequest)

      var writeFn = res.write

      // catch content-length of payload
      res.write = function (payload) {
        if (payload) byteLength += payload.length
        return writeFn.apply(res, arguments)
      }
    }

    next()
  }

  httpLogger.ignores = [].concat(opts.ignores).filter(Boolean)
  httpLogger.type = 'static'
  return httpLogger
}

function recordStartTime () {
  this._startAt = process.hrtime()
}