#!/usr/bin/env node

var arrayToTable = require('array-to-table')
var program = require('commander')
var breeze = require('breeze')
var github = require("github")
var semver = require('semver')
var moment = require('moment')
var pkg = require('../package.json')
var log = require('npmlog')
var file = require('easy-file')

// Directory Location
var configurationFileLocation = [__dirname, '.config'].join('/')

// Regex Helpers
var scopeRegex = /^\w+\s?\(([^\)]+)\)\:/
var shaRegex = /(\b[0-9a-f]{7,40})/img
var issueRegex = /\#([0-9]+)/ig

// Configure logger
log.heading = "niji"

program.version(pkg.version)
program.option('-o, --out [directory]', 'Location of the directory to output changelog')
program.option('-r, --repo [name]', 'Repository name')
program.option('-u, --user [name]', 'Repository username')
program.option('-h, --head [name]', 'Commit head')
program.option('-b, --base [name]', 'Commit base')
program.option('-f, --format [option]', 'Changelog Format Type (table (default), node, node+, angular)')
program.option('-s, --sort [option]', 'Sorting option (time (default), type, scope, author)')
program.option('-t, --token [token]', 'Github Token')
program.option('-c, --configure [token]', 'Configure github token for future reference')
program.parse(process.argv)

function getVersion (head) {
  if (!head) return 'Unknown'
  var parts = head.split('/')
  return head.indexOf('/') > -1 ? 'v' + semver.clean(parts[parts.length-1]) : head
}

function sort (fields) {
  return function (a, b) {
    return fields.map(function (o) {
      var dir = 1
      if (o[0] === '-') dir = -1, o=o.substring(1)
      return a[o] > b[o] ? dir : a[o] < b[o] ? -(dir) : 0
    }).reduce(function (p, n) { return p ? p : n }, 0)
  }
}

function determineType (message) {
  message = message ? message.toLowerCase() : ''
  switch (true) {
    case (message.indexOf('feat') === 0):
      return 'Feature'
    case (message.indexOf('docs') === 0):
      return 'Documentation'
    case (message.indexOf('style') === 0):
      return 'Style'
    case (message.indexOf('test') === 0):
      return 'Tests'
    case (message.indexOf('perf') === 0):
      return 'Performance'
    case (message.indexOf('chore') === 0):
      return 'Chore'
    case (message.indexOf('release') === 0):
      return 'Release'
    case (message.indexOf('misc') === 0):
      return 'Misc'
    case (message.indexOf('fix') !== -1):
      return 'Fixed'
    case (message.indexOf('revert') !== -1):
      return 'Reverted'
    case (message.indexOf('add') !== -1):
      return 'Added'
    case (message.indexOf('change') !== -1):
      return 'Changed'
    default:
      return 'Changed'
  }
}

function determineScope (message) {
  var matches = message.match(scopeRegex)
  return matches && matches.length ? matches[1] : ""
}

function determineReferences (message) {
  var repoUrl = [ 'https://github.com/', program.user, '/', program.repo, '/' ].join('')
  var issues = message.match(issueRegex)
  var output = ""

  ;(issues || []).forEach(function (id) {
    output += "[`" + id + "`](" + repoUrl + "commit/" + id + "), "
  })

  return output.length ? output.substr(0, output.length - 2) : output
}

function determineDescription (message) {
  var repoUrl = [ 'https://github.com/', program.user, '/', program.repo, '/' ].join('')
  var index

  // Get first entry
  message = message.split("\n")
  message = message.shift()

  // Remove type and scope.
  if (message.indexOf(':') > -1) {
    message = message.split(":")
    message.shift()
    message = message.join(":")
  }

  // Replace issues with link
  ;(message.match(issueRegex) || []).forEach(function (issueId) {
    var id = issueId.replace('#', '')
    message = message.replace(issueId, '[`' + issueId + '`](' + repoUrl + 'issues/' + id + ')')
  })

  // Replace sha with link
  ;(message.match(shaRegex) || []).forEach(function (sha) {
    message = message.replace(sha, '[`' + sha.substr(0, 7) + '`](' + repoUrl + 'commit/' + sha + ')')
  })

  // Return message
  return message
}

function generateAngularChangelog (commits) {
  var version = getVersion(program.head)
  let versionLink = ['[`', version, '`](https://github.com/', program.user, '/', program.repo, '/tree/', program.head, ')'].join('')
  let changelog = {}
  let output = []

  output.push(['## ', versionLink, ' ', `(${ moment().format('YYYY-MM-DD') })`].join(''))
  output.push('')

  commits.filter(commit => commit.Type && commit.Scope).sort((a, b) => {
    let aScope = a.Scope.toLowerCase()
    let bScope = b.Scope.toLowerCase()
    return aScope === bScope ? 0 : aScope < bScope ? -1 : 1
  }).forEach(commit => {
    if (!commit.Type || !commit.Scope) return
    if (!changelog[commit.Type]) {
      changelog[commit.Type] = []
    }

    changelog[commit.Type].push([
      '-', `**${commit.Scope}:**`, commit.Description, `(${commit.Link})`
    ].join(' '))
  })

  Object.keys(changelog).forEach(type => {
    output.push([
      `### ${type}`, changelog[type].join('\r\n')
    ].join('\r\n'))
    output.push('')
  })

  return output.join('\r\n')
}

function generateNodeChangelogResult (commits) {
  var output = []
  var version = getVersion(program.head)

  output.push(['## ', moment().format('YYYY-MM-DD'), ', Version ', version].join(''))
  output.push('### Notable Changes')
  output.push('')
  output.push('- Enter Notable Changes Here')
  output.push('')
  output.push('### Commits')

  commits.forEach(function (commit) {
    output.push(['- [', commit.Link, '] ' + (commit.Scope ? ('**' + commit.Type + '(' + commit.Scope + ')' + ':** ') : ''), commit.Description, ' (', commit.Author, ')'].join(''))
  })

  return output.join("\r\n")
}

function generateDefaultChangelogResult (commits) {
  var output = []
  var version = getVersion(program.head)

  output.push(['## [', version, '] | ', moment().format('YYYY-MM-DD')].join(''))
  output.push(['*branch:', '[`', program.head, '`](https://github.com/', program.user, '/', program.repo, '/tree/', program.head, ')*'].join(''))
  output.push('')

  try {
    output.push(arrayToTable(commits))
  } catch (e) {
    console.log(e)
  }

  output.push(['[', version, ']: ', 'https://github.com/', program.user, '/', program.repo, '/compare/', program.base, '...', program.head].join(''))

  return output.join("\r\n")
}

function compareCommits (gh) {
  return function (next) {
    gh.repos.compareCommits({
      user: program.user,
      repo: program.repo,
      base: program.base,
      head: program.head
    }, next)
  }
}

function transformCommits (next, results) {
  var commits = []

  results.commits.forEach(function (entry) {
    var message = entry.commit.message.toLowerCase()
    var uri = entry.html_url.split('/')

    if (message.indexOf('merge') === 0 || message.indexOf(':') === -1) {
      return
    }

    commits.push({
      "Type": determineType(entry.commit.message),
      "Scope": determineScope(entry.commit.message),
      "Link": ['[`', uri[uri.length - 1].substring(0, 10) ,'`](', entry.html_url, ')'].join(''),
      "Description": determineDescription(entry.commit.message),
      "References": determineReferences(entry.commit.message),
      "Author": entry.commit.author.name
    })
  })

  if (program.sort === 'type,scope') {
    commits = commits.sort(sort(['Type', 'Scope']))
  }

  if (program.sort === 'scope,type') {
    commits = commits.sort(sort(['Scope', 'Type']))
  }

  if (program.sort === 'scope') {
    commits = commits.sort(sort(['Scope']))
  }

  if (program.sort === 'type') {
    commits = commits.sort(sort(['Type']))
  }

  if (program.sort === 'author') {
    commits = commits.sort(sort(['Author']))
  }

  next(null, commits)
}

function outputReleaseResultsFile (next, commits) {
  console.info('coming soon...')
}

function consoleLogReleaseResults (next, commits) {
  console.log(
      program.format === 'node' 
    ? generateNodeChangelogResult(commits)
    : program.format === 'angular'
    ? generateAngularChangelog(commits)
    : generateDefaultChangelogResult(commits)
  )
}

if (program.configure) {
  log.info('setting', 'configuration file: %s', configurationFileLocation)
  log.info('config', 'set "token" "%s"', program.configure)

  try {
    file.write(configurationFileLocation, JSON.stringify({ token: program.configure }, null, 2))
  } catch (e) {
    log.error('config', e.message)
    process.exit(1)
  } finally {
    log.info('ok')
    process.exit(0)
  }
}

file.read(configurationFileLocation, function (config) {
  var flow = breeze()
  var gh = new github({
    version: "3.0.0",
    headers: {
      "user-agent": "changelog-generator"
    }
  })

  if (!program.token && config) {
    config = JSON.parse(config)
    program.token = config.token
  }

  gh.authenticate({
    type: "token",
    token: program.token
  })

  flow.then(compareCommits(gh))
  flow.then(transformCommits)
  flow.some(program.out, outputReleaseResultsFile)
  flow.none(consoleLogReleaseResults)

  flow.catch(function onError (err) {
    console.error('Unable to generate release results:', err.message)
    console.error(err.stack)
  })
})