'use strict'

const { SourceMapConsumer } = require('source-map')

module.exports = function stackTraceMapper (stack, map) {
  if (!(map instanceof SourceMapConsumer)) {
    throw new Error('map is not a consumer')
  }

  const setups = [
    {
      // settings for Chrome, Edge and IE (Plus?)
      regex: /\s+at(?:\s+([^\s]+))?\s\(?([/a-z0-9:.-]+):([0-9]+):([0-9]+)/,
      // regex: /\s+at(?:\s+([^)]+))?\s\(?([/a-z0-9:.-]+):([0-9]+):([0-9]+)/,
      skip: 1,
      split: /\n?(?= at )/,
    },

    {
      // settings for Firefox and Safari
      regex: /([a-zA-Z0-9]*)@(.*):([0-9]+):([0-9]+)/,
      skip: 0,
      split: /\s+/,
    },
  ]

  const setup = setups.find((setup) => {
    return setup.regex.test(stack)
  })

  if (!setup) {
    throw new Error('Stack trace is not recognised')
  }

  const split = stack.trim().split(setup.split)
  // TODO whether the error name and similar preludes the stack varies between browsers perhaps we should create one
  const pre = split.slice(0, setup.skip)
  console.log('split', split)
  console.log('pre', pre)

  const lines = split.slice(setup.skip).map((source) => {
    // TODO handle lines that have not matched
    const match = source.match(setup.regex)

    if (!match) {
      return { source }
    }

    const [ , fnc, file, line, column ] = match

    return { fnc, file, line: parseInt(line), column: parseInt(column), source }
  })

  const originalLines = lines.map((obj) => {
    if (obj.line) {
      return map.originalPositionFor({ line: obj.line, column: obj.column })
    }

    return obj
  })

  // need to do research as to why, but the original line objects returned
  // contain the function call names are shifted one line compared with
  // the sourcemapped stack printed in chrome dev tools
  const adjustedLines = originalLines.map((obj, index, arr) => {
    if (obj.line) {
      const prev = arr[index + 1]

      obj.name = (prev && prev.name) || undefined
    }

    return obj
  })

  return pre.concat(adjustedLines.map(formatLine))
}

function formatLine ({ source, line, column, name = '(unknown)' }) {
  if (!line || !column) {
    return `   ${source}`
  }

  return `    at ${name} (${source}:${line}:${column})`
}