/* ----------------------------------------------------------------------------

 Question Server
 GitLab: <https://gitlab.com/MrFry/mrfrys-node-server>

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program. If not, see <https://www.gnu.org/licenses/>.

 ------------------------------------------------------------------------- */

const recDataFile = './stats/recdata'
const dataLockFile = './data/lockData'

import logger from '../utils/logger'
import {
    createQuestion,
    WorkerResult,
    SearchResultQuestion,
} from '../utils/classes'
import { doALongTask, msgAllWorker } from './workerPool'
import idStats from '../utils/ids'
import utils from '../utils/utils'
import { addQuestion, getSubjNameWithoutYear } from './classes'

// types
import {
    QuestionDb,
    Subject,
    Question,
    User,
    DataFile,
} from '../types/basicTypes'

// if a recievend question doesnt match at least this % to any other question in the db it gets
// added to db
const minMatchAmmountToAdd = 90

const writeAfter = 1 // write after # of adds FIXME: set reasonable save rate
let currWrites = 0

export interface RecievedData {
    quiz: Array<Question>
    subj: string
    id: string
    version: string
    location: string
}

export interface Result {
    qdbIndex: number
    qdbName: string
    subjName: string
    newQuestions: Array<Question>
}

export function logResult(
    recievedData: RecievedData,
    result: Array<Result>,
    userId: number,
    dryRun?: boolean
): void {
    logger.Log('\t' + recievedData.subj)

    if (dryRun) {
        logger.Log('\tDry run')
    }

    let idRow = '\t'
    if (recievedData.version) {
        idRow += 'Version: ' + logger.logHashed(recievedData.version)
    }
    if (recievedData.id) {
        idRow += ', CID: ' + logger.logHashed(recievedData.id)
    }
    idRow += `, User #${logger.logHashed(userId.toString())}`
    logger.Log(idRow)

    if (result.length > 0) {
        result.forEach((res: Result) => {
            const allQLength = recievedData.quiz.length
            let msg = `${res.qdbName}: `
            let color = logger.GetColor('green')
            if (res.newQuestions.length > 0) {
                color = logger.GetColor('blue')
                msg += `New questions: ${res.newQuestions.length} ( All: ${allQLength} )`
            } else {
                msg += `No new data ( ${allQLength} )`
            }
            logger.Log('\t' + msg, color)
        })
    } else {
        logger.Log('\tResults length is zero!', logger.GetColor('red'))
    }
}

export function processIncomingRequest(
    recievedData: RecievedData,
    questionDbs: Array<QuestionDb>,
    dryRun: boolean,
    user: User
): Promise<Array<Result>> {
    logger.DebugLog('Processing incoming request', 'isadding', 1)

    if (recievedData === undefined) {
        logger.Log('\tRecieved data is undefined!', logger.GetColor('redbg'))
        throw new Error('Recieved data is undefined!')
    }

    try {
        let towrite = utils.GetDateString() + '\n'
        towrite +=
            '------------------------------------------------------------------------------\n'
        if (typeof recievedData === 'object') {
            towrite += JSON.stringify(recievedData)
        } else {
            towrite += recievedData
        }
        towrite +=
            '\n------------------------------------------------------------------------------\n'
        utils.AppendToFile(towrite, recDataFile)
        logger.DebugLog('recDataFile written', 'isadding', 1)
    } catch (err) {
        logger.Log('Error writing recieved data.')
    }

    if (utils.FileExists(dataLockFile)) {
        logger.Log(
            'Data lock file exists, skipping recieved data processing',
            logger.GetColor('red')
        )
        return new Promise((resolve) => resolve([]))
    }

    // FIXME: this many promises and stuff might be unnecesarry
    const promises: Array<Promise<Result>> = questionDbs.reduce((acc, qdb) => {
        acc.push(processIncomingRequestUsingDb(recievedData, qdb, dryRun, user))
        return acc
    }, [])
    return Promise.all(promises)
}

function processIncomingRequestUsingDb(
    recievedData: RecievedData,
    qdb: QuestionDb,
    dryRun: boolean,
    user: User
): Promise<Result> {
    return new Promise((resolve, reject) => {
        try {
            const recievedQuestions: Question[] = []

            logger.DebugLog('recievedData JSON  parsed', 'isadding', 1)
            logger.DebugLog(recievedData, 'isadding', 3)
            const allQLength = recievedData.quiz.length
            const questionSearchPromises: Promise<WorkerResult>[] = []
            recievedData.quiz.forEach((question) => {
                logger.DebugLog('Question:', 'isadding', 2)
                logger.DebugLog(question, 'isadding', 2)
                const currentQuestion = createQuestion(
                    question.Q,
                    question.A,
                    question.data
                )
                logger.DebugLog(
                    'Searching for question in subj ' + recievedData.subj,
                    'isadding',
                    3
                )
                logger.DebugLog(currentQuestion, 'isadding', 3)
                if (isQuestionValid(currentQuestion)) {
                    recievedQuestions.push(currentQuestion)
                    // This here searches only in relevant subjects, and not all subjects
                    questionSearchPromises.push(
                        doALongTask({
                            type: 'work',
                            data: {
                                searchIn: [qdb.index],
                                question: currentQuestion,
                                subjName: recievedData.subj,
                                searchTillMatchPercent: minMatchAmmountToAdd,
                            },
                        })
                    )
                } else {
                    logger.DebugLog('Question isnt valid', 'isadding', 1)
                    logger.DebugLog(currentQuestion, 'isadding', 1)
                }
            })

            Promise.all(questionSearchPromises)
                .then((results: Array<WorkerResult>) => {
                    const allQuestions: Question[] = [] // all new questions here that do not have result
                    results.forEach((result: WorkerResult, i) => {
                        const add = (
                            result.result as SearchResultQuestion[]
                        ).every((res: SearchResultQuestion) => {
                            return res.match < minMatchAmmountToAdd
                        })
                        if (add && !result.error) {
                            allQuestions.push(recievedQuestions[i])
                        }
                    })

                    try {
                        const subjName = getSubjNameWithoutYear(
                            recievedData.subj
                        )
                        if (allQuestions.length > 0) {
                            addQuestionsToDb(allQuestions, subjName, qdb)

                            currWrites++
                            logger.DebugLog(
                                'currWrites for data.json: ' + currWrites,
                                'isadding',
                                1
                            )
                            if (currWrites >= writeAfter && !dryRun) {
                                currWrites = 0
                                logger.DebugLog(
                                    'Writing data.json',
                                    'isadding',
                                    1
                                )
                                writeData(qdb.data, qdb.path)
                            }
                        }

                        idStats.LogId(
                            user.id,
                            recievedData.subj,
                            allQuestions.length,
                            allQLength
                        )

                        logger.DebugLog('New Questions:', 'isadding', 2)
                        logger.DebugLog(allQuestions, 'isadding', 2)

                        logger.DebugLog(
                            'ProcessIncomingRequest done',
                            'isadding',
                            1
                        )
                        resolve({
                            newQuestions: allQuestions,
                            subjName: recievedData.subj,
                            qdbIndex: qdb.index,
                            qdbName: qdb.name,
                        })
                        runCleanWorker(recievedData.quiz, subjName, qdb)
                    } catch (error) {
                        console.error(error)
                        logger.Log(
                            'Error while processing processData worker result!',
                            logger.GetColor('redbg')
                        )
                        reject(
                            new Error(
                                'Error while processing processData worker result!'
                            )
                        )
                    }
                })
                .catch((err) => {
                    logger.Log(
                        'Error while searching for questions in ProcessIncomingRequest!',
                        logger.GetColor('redbg')
                    )
                    console.error(err)
                })
        } catch (err) {
            console.error(err)
            logger.Log(
                'There was en error handling incoming quiz data, see stderr',
                logger.GetColor('redbg')
            )
            reject(new Error('Couldnt parse JSON data'))
        }
    })
}

function addQuestionsToDb(
    allQuestions: Question[],
    subjName: string,
    qdb: QuestionDb
) {
    allQuestions.forEach((currentQuestion) => {
        logger.DebugLog(
            'Adding question with subjName: ' + subjName + ' :',
            'isadding',
            3
        )
        logger.DebugLog(currentQuestion, 'isadding', 3)
        addQuestion(qdb.data, subjName, {
            ...currentQuestion,
            data: {
                ...currentQuestion.data,
                date: new Date().getTime(),
            },
        })
    })
}

function runCleanWorker(
    recievedQuesitons: Question[],
    subjName: string,
    qdb: QuestionDb
) {
    if (qdb.overwrites && qdb.overwrites.length) {
        // check if subject needs to be updated, and qdb has overwriteFromDate
        const overwrite = qdb.overwrites.find((x) => {
            return subjName.toLowerCase().includes(x.subjName.toLowerCase())
        })

        if (!overwrite) {
            return
        }
        // logger.Log(
        //   `\tStarting cleaning in subject "${logger.C(
        //     'green'
        //   )}${subjName}${logger.C('')}" (matched: "${logger.C('green')}${
        //     overwrite.subjName
        //   }${logger.C('')}")`
        // )
        // pass recieved questions to a worker
        doALongTask({
            type: 'dbClean',
            data: {
                questions: recievedQuesitons,
                subjToClean: subjName,
                overwriteFromDate: overwrite.overwriteFromDate,
                qdbIndex: qdb.index,
            },
        }).then(({ result: questionIndexesToRemove }) => {
            const subjIndex = qdb.data.findIndex((x) => {
                return x.Name.toLowerCase().includes(subjName.toLowerCase())
            })
            //   sends msgs to all workers to remove it too

            msgAllWorker({
                type: 'rmQuestions',
                data: {
                    questionIndexesToRemove:
                        questionIndexesToRemove as number[][],
                    subjIndex: subjIndex,
                    qdbIndex: qdb.index,
                    recievedQuestions: recievedQuesitons,
                },
            })

            //   it adds the recieved question WITH DATE!
            //     recievedQuestions doesnt have date-s
            qdb.data[subjIndex].Questions = updateQuestionsInArray(
                questionIndexesToRemove as number[][],
                qdb.data[subjIndex].Questions,
                recievedQuesitons
            )

            //   saves the file
            writeData(qdb.data, qdb.path)
            logger.Log(
                `\tRemoved ${logger.C('green')}${
                    (questionIndexesToRemove as number[][]).filter(
                        (x: number[]) => x.length > 1
                    ).length
                }${logger.C()} old questions from ${logger.C(
                    'green'
                )}${subjName}${logger.C()}`
            )
        })
    }
}

export function updateQuestionsInArray(
    questionIndexesToRemove: number[][],
    questions: Question[],
    newQuestions: Question[]
): Question[] {
    const indexesToRemove = questionIndexesToRemove.reduce((acc, x) => {
        if (x.length > 1) {
            return [...acc, ...x]
        }
        return acc
    }, [])

    const newQuestionsToAdd: Question[] = newQuestions.filter((_q, i) => {
        return questionIndexesToRemove[i].length > 1
    })

    return [
        ...questions.filter((_x, i) => {
            return !indexesToRemove.includes(i)
        }),
        ...newQuestionsToAdd.map((x) => {
            x.data.date = new Date()
            return x
        }),
    ]
}

export function isQuestionValid(question: Question): boolean {
    if (!question.Q) {
        return false
    }
    if (!question.A && question.data.type === 'simple') {
        return false
    }
    return true
}

export function shouldSearchDataFile(
    df: DataFile,
    testUrl: string,
    trueIfAlways?: boolean
): boolean {
    if (
        typeof df.shouldSearch === 'string' &&
        df.shouldSearch === 'always' &&
        trueIfAlways
    ) {
        return true
    }

    if (typeof df.shouldSearch === 'object') {
        if (df.shouldSearch.location) {
            const { val } = df.shouldSearch.location
            return testUrl.includes(val)
        }
    }

    logger.DebugLog(`no suitable dbs for ${testUrl}`, 'shouldSearchDataFile', 1)
    return false
}

export function shouldSaveDataFile(
    df: DataFile,
    recievedData: RecievedData
): boolean {
    if (df.locked) {
        return false
    }

    if (df.shouldSave.version) {
        const { compare, val } = df.shouldSave.version
        if (compare === 'equals') {
            return recievedData.version === val
        } else if (compare === 'startsWith') {
            return recievedData.version.startsWith(val)
        }
    }

    if (df.shouldSave.version) {
        const { compare, val } = df.shouldSave.version
        if (compare === 'equals') {
            return recievedData.version === val
        } else if (compare === 'startsWith') {
            return recievedData.version.startsWith(val)
        }
    }

    if (df.shouldSave.location) {
        const { val } = df.shouldSave.location
        return recievedData.location.includes(val)
    }

    return false
}

export function loadData(path: string): Array<Subject> {
    return JSON.parse(utils.ReadFile(path)).map((subj: Subject) => {
        return {
            Name: subj.Name,
            Questions: subj.Questions.map((question: Question) => {
                return createQuestion(question)
            }),
        }
    })
}

export function loadJSON(
    dataFiles: Array<DataFile>,
    dataDir: string
): Array<QuestionDb> {
    const res: Array<QuestionDb> = dataFiles.reduce((acc, dataFile, index) => {
        const dataPath = dataDir + dataFile.path

        if (!utils.FileExists(dataPath)) {
            utils.WriteFile(JSON.stringify([]), dataPath)
        }

        try {
            acc.push({
                ...dataFile,
                path: dataPath,
                index: index,
                data: loadData(dataPath),
            })
        } catch (err) {
            console.error(err)
            logger.Log(
                "data is undefined! Couldn't load data!",
                logger.GetColor('redbg')
            )
        }
        return acc
    }, [])

    let subjCount = 0
    let questionCount = 0
    res.forEach((qdb) => {
        subjCount += qdb.data.length
        qdb.data.forEach((subj) => {
            questionCount += subj.Questions.length
        })
    })
    logger.Log(
        `Loaded ${subjCount} subjects with ${questionCount} questions from ${res.length} question db-s`,
        logger.GetColor('green')
    )

    return res
}

export function writeData(data: Array<Subject>, path: string): void {
    utils.WriteFile(
        JSON.stringify(
            data.map((subj) => {
                return {
                    Name: subj.Name,
                    Questions: subj.Questions.map((question) => {
                        return {
                            Q: question.Q,
                            A: question.A,
                            data: question.data,
                        }
                    }),
                }
            })
        ),
        path
    )
}

export function backupData(questionDbs: Array<QuestionDb>): void {
    questionDbs.forEach((data) => {
        const path = './publicDirs/qminingPublic/backs/'
        utils.CreatePath(path)
        try {
            // logger.Log(`Backing up ${data.name}...`)
            writeData(
                data.data,
                `${path}${data.name}_${utils.GetDateString(
                    undefined,
                    true
                )}.json`
            )
            // logger.Log('Done')
        } catch (err) {
            logger.Log(
                `Error backing up data file ${data.name}!`,
                logger.GetColor('redbg')
            )
            console.error(err)
        }
    })
}

function deleteFromDb(
    questionDb: QuestionDb,
    edits: {
        index: number
        subjName: string
        type: string
        selectedDb: { path: string; name: string }
    }
): {
    success: boolean
    msg: string
    deletedQuestion?: Question
    resultDb?: QuestionDb
} {
    // {
    //   "index": 0,
    //   "subjName": "VHDL programozás",
    //   "type": "delete",
    //   "selectedDb": {
    //     "path": "questionDbs/elearning.uni-obuda.hu.json",
    //     "name": "elearning.uni-obuda.hu"
    //   }
    // }
    const { index, subjName } = edits
    let deletedQuestion: Question
    if (isNaN(index) || !subjName) {
        return {
            success: false,
            msg: 'No .index or .subjName !',
        }
    }

    questionDb.data = questionDb.data.map((subj) => {
        if (subj.Name !== subjName) {
            return subj
        } else {
            return {
                ...subj,
                Questions: subj.Questions.filter((question, i) => {
                    if (index === i) {
                        deletedQuestion = question
                        return false
                    } else {
                        return true
                    }
                }),
            }
        }
    })

    return {
        success: true,
        msg: 'Delete successfull',
        deletedQuestion: deletedQuestion,
        resultDb: questionDb,
    }
}

function editQuestionInDb(
    questionDb: QuestionDb,
    edits: {
        index: number
        subjName: string
        type: string
        selectedDb: { path: string; name: string }
        newVal: Question
    }
): {
    success: boolean
    msg: string
    newVal?: Question
    oldVal?: Question
    resultDb?: QuestionDb
} {
    // {
    //   "index": 0,
    //   "subjName": "Elektronika",
    //   "type": "edit",
    //   "newVal": {
    //     "Q": "Analóg műszer esetén az érzékenység az a legkisebb mennyiség, amely a műszer kijelzőjén meghatározott mértékű változást okoz.",
    //     "A": "Igaz",
    //     "data": {
    //       "type": "simple",
    //       "possibleAnswers": [
    //         "Igaz"
    //       ]
    //     },
    //     "possibleAnswers": [
    //       "Igaz"
    //     ]
    //   },
    //   "selectedDb": {
    //     "path": "questionDbs/elearning.uni-obuda.hu.json",
    //     "name": "elearning.uni-obuda.hu"
    //   }
    // }
    const { index, subjName, newVal } = edits

    let oldVal: Question
    if (isNaN(index) || !subjName) {
        return {
            success: false,
            msg: 'No .index or .subjName !',
        }
    }
    if (!isQuestionValid(newVal)) {
        return {
            success: false,
            msg: 'edited question is not valid',
        }
    }

    questionDb.data = questionDb.data.map((subj) => {
        if (subj.Name !== subjName) {
            return subj
        } else {
            return {
                ...subj,
                Questions: subj.Questions.map((question, i) => {
                    if (index === i) {
                        oldVal = question
                        return createQuestion(newVal)
                    } else {
                        return question
                    }
                }),
            }
        }
    })

    return {
        success: true,
        msg: 'Edit successfull',
        oldVal: oldVal,
        newVal: newVal,
        resultDb: questionDb,
    }
}

function editSubjInDb(
    questionDb: QuestionDb,
    edits: {
        index: number
        subjName: string
        type: string
        selectedDb: { path: string; name: string }
        deletedQuestions?: Array<number>
        changedQuestions?: Array<{
            index: number
            value: Question
        }>
    }
): {
    success: boolean
    msg: string
    deletedQuestions?: Array<Question>
    changedQuestions?: { oldVal: Question; newVal: Question }[]
    resultDb?: QuestionDb
} {
    // {
    //   "subjName": "Elektronika",
    //   "changedQuestions": [
    //     {
    //       "index": 1,
    //       "value": {
    //         "Q": "A műszer pontosságát a hibájával fejezzük ki, melyet az osztályjel (osztálypontosság ) mutat meg.",
    //         "A": "Hamis",
    //         "data": {
    //           "type": "simple",
    //           "possibleAnswers": [
    //             "Igaz",
    //             "Hamis"
    //           ]
    //         }
    //       }
    //     }
    //   ],
    //   "deletedQuestions": [
    //     0
    //   ],
    //   "type": "subjEdit",
    //   "selectedDb": {
    //     "path": "questionDbs/elearning.uni-obuda.hu.json",
    //     "name": "elearning.uni-obuda.hu"
    //   }
    // }
    const { subjName, changedQuestions, deletedQuestions } = edits
    const deletedQuestionsToWrite: Question[] = []
    const changedQuestionsToWrite: { oldVal: Question; newVal: Question }[] = []
    if (!Array.isArray(changedQuestions) || !Array.isArray(deletedQuestions)) {
        return {
            success: false,
            msg: 'no changedQuestions or deletedQuestions!',
        }
    }

    // processing changed questions
    questionDb.data = questionDb.data.map((subj) => {
        if (subj.Name !== subjName) {
            return subj
        } else {
            return {
                ...subj,
                Questions: subj.Questions.map((question, i) => {
                    const changedTo = changedQuestions.find((cq) => {
                        return cq.index === i
                    })
                    if (changedTo) {
                        changedQuestionsToWrite.push({
                            oldVal: question,
                            newVal: changedTo.value,
                        })
                        return createQuestion(changedTo.value)
                    } else {
                        return question
                    }
                }),
            }
        }
    })

    // processing deletedQuestions
    questionDb.data = questionDb.data.map((subj) => {
        if (subj.Name !== subjName) {
            return subj
        } else {
            return {
                ...subj,
                Questions: subj.Questions.filter((question, i) => {
                    const isDeleted = deletedQuestions.includes(i)
                    if (isDeleted) {
                        deletedQuestionsToWrite.push(question)
                        return false
                    } else {
                        return true
                    }
                }),
            }
        }
    })

    return {
        success: true,
        msg: 'subj edit successfull',
        deletedQuestions: deletedQuestionsToWrite,
        changedQuestions: changedQuestionsToWrite,
        resultDb: questionDb,
    }
}

// FIXME: newVal is optional in some places but not in others
export interface Edits {
    index: number
    subjName: string
    selectedDb: { path: string; name: string }
    type: string
    newVal: Question
    deletedQuestion?: Array<number>
    changedQuestions?: Array<{
        index: number
        value: Question
    }>
}

export function editDb(
    questionDb: QuestionDb,
    edits: Edits
): {
    success: boolean
    msg: string
    resultDb?: QuestionDb
    deletedQuestion?: Question
    newVal?: Question
    oldVal?: Question
    deletedQuestions?: Array<Question>
    changedQuestions?: { oldVal: Question; newVal: Question }[]
} {
    if (edits.type === 'delete') {
        return deleteFromDb(questionDb, edits)
    }
    if (edits.type === 'edit') {
        return editQuestionInDb(questionDb, edits)
    }

    if (edits.type === 'subjEdit') {
        return editSubjInDb(questionDb, edits)
    }

    return {
        success: false,
        msg: 'DB edit error, no matched type',
    }
}