import htmlparser, json, net, options, os, strscans, times, unicode, uri, xmltree
from strutils import ffDecimal, formatFloat, replace
import cligen, colorize, elvis
from bakalari as baka import Grade, newBakalari

type
  Config = object
    website: string
    username: string
    refreshToken: string

const
  defaultConfigFile = getConfigDir() / "bk.json"
  dayNames = [
    1: "Mon",
    2: "Tue",
    3: "Wed",
    4: "Thu",
    5: "Fri",
    6: "Sat",
    7: "Sun",
  ]

proc error(message: string) {.noReturn.} =
  stderr.writeLine("Error: " & message)
  quit QuitFailure

proc loadConfig(configFile = defaultConfigFile): Config =
  try:
    configFile.readFile.parseJson.to(Config)
  except IOError:
    error "Can't read the config file. Are you signed in?"
  except JsonParsingError, JsonKindError:
    error "Invalid config file. Make sure it's in JSON format."
  except KeyError:
    error "The config file doesn't contain all necessary fields."

proc saveConfig(configFile = defaultConfigFile, config: Config) =
  try:
    configFile.writeFile((%*config).pretty)
  except IOError:
    error "Can't write the config file."

template withBakalari(configFile: string, body: untyped): untyped =
  var config = configFile.loadConfig
  let bakalari {.inject.} = newBakalari(config.website.parseUri, config.refreshToken)
  try:
    body
  finally:
    config.refreshToken = bakalari.refreshToken
    configFile.saveConfig(config)

proc signin(
  website: string,
  username: string,
  password: string,
  configFile = defaultConfigFile,
  ) =
  ## sign in to Bakaláři and save the credentials
  let
    bakalari = newBakalari(website.parseUri, username, password)
    config = Config(
      website: website,
      username: username,
      refreshToken: bakalari.refreshToken,
    )
  configFile.saveConfig(config)

proc average(grades: seq[Grade]): float =
  var sum, weightSum: float
  for grade in grades:
    var value: int
    if scanf(grade.text, "$i-", value):
      sum += (value.float + 0.5) * grade.weight.float
      weightSum += grade.weight.float
    elif scanf(grade.text, "$i", value):
      sum += value.float * grade.weight.float
      weightSum += grade.weight.float
  return weightSum ? (sum / weightSum) ! 0.0

proc grades(
  configFile = defaultConfigFile,
  ) =
  ## display the list of grades and calculate averages
  withBakalari(configFile):
    for subject in baka.grades(bakalari):
      stdout.writeLine subject.name.fgLightYellow & " " & subject.grades.average.formatFloat(ffDecimal, 2)
      for grade in subject.grades:
        var line = ""
        line &= grade.text.align(2).fgLightMagenta
        line &= " "
        line &= ($grade.weight).align(2).fgLightCyan
        line &= " "
        line &= grade.caption
        stdout.writeLine line

proc homework(
  configFile = defaultConfigFile,
  ) =
  ## display the list of homework
  withBakalari(configFile):
    for homework in baka.homework(bakalari):
      stdout.writeLine "----------------------------------------------------------------".fgLightGray
      stdout.writeLine (homework.startTime.format("yyyy-MM-dd") & " / " & homework.endTime.format("yyyy-MM-dd")).fgLightCyan
      stdout.writeLine homework.subject.fgLightYellow
      stdout.writeLine homework.teacher.fgLightMagenta
      stdout.writeLine homework.content

proc messages(
  configFile = defaultConfigFile,
  ) =
  withBakalari(defaultConfigFile):
    for message in baka.messages(bakalari):
      stdout.writeLine "----------------------------------------------------------------".fgLightGray
      stdout.writeLine message.sentTime.format("yyyy-MM-dd") .fgLightCyan
      stdout.writeLine message.title.fgLightYellow
      stdout.writeLine message.sender.fgLightMagenta
      stdout.writeLine message.text.replace("<br />", "{{br}}").parseHtml.innerText.replace("{{br}}", "\n")

proc timetable(
  configFile = defaultConfigFile,
  date = "",
  nextWeek = false,
  oneDay = false,
  permanent = false,
  ) =
  ## display the timetable (for the current week by default)
  let date = if ?date:
    try:
      date.parse("yyyyMMdd")
    except TimeParseError:
      error "Can't parse the date. Make sure it's in YYYYMMDD format."
  else:
    nextWeek ? (now() + 1.weeks) ! now()
  withBakalari(configFile):
    let timetable = baka.timetable(bakalari, permanent, some(date))
    for day in timetable.days:
      if oneDay:
        if date.format("yyyyMMdd") != day.date.format("yyyyMMdd"):
          continue
      stdout.writeLine dayNames[day.dayOfWeek] & " " & day.date.format("yyyy-MM-dd")
      for lesson in day.lessons:
        var line = ""
        line &= lesson.hour.number
        line &= ". "
        line &= lesson.hour.beginTime.align(5, '0'.Rune).fgLightCyan
        line &= "-".fgLightCyan
        line &= lesson.hour.endTime.align(5, '0'.Rune).fgLightCyan
        line &= " "
        line &= lesson.subject.abbrev.align(4).fgLightYellow
        line &= " "
        line &= lesson.teacher.abbrev.align(4).fgLightMagenta
        line &= " "
        line &= lesson.room.abbrev.align(4).fgLightGreen
        stdout.writeLine line
        if lesson.change.isSome:
          stdout.writeLine ("^ " & lesson.change.unsafeGet.fgLightRed).fgLightRed

try:
  dispatchMulti(
    [signin, help = {
      "website": "the URL for Bakaláři (e.g. https://bakalari.myschool.cz)",
      "username": "your username",
      "password": "your password (will not be stored anywhere)",
      "config-file": "where to store the credentials",
    }],
    [grades, help = {
      "config-file": "where the credentials are stored",
    }],
    [homework, help = {
      "config-file": "where the credentials are stored",
    }],
    [messages, help = {
      "config-file": "where the credentials are stored",
    }],
    [timetable, help = {
      "config-file": "where the credentials are stored",
      "date": "any date inside the week you want to display, in YYYYMMDD format (defaults to today)",
      "nextWeek": "display the next week rather that the current week (overriden by --date)",
      "one-day": "display only the specified day",
      "permanent": "display the permanent timetable",
    }],
    )
except OSError:
  error "Generic OS error. Check your internet connection."
except SslError:
  error "Connection interrupted. Check your internet connection."