import enquirer from "enquirer"
import {watch, constants as fsConstants} from "fs"
import {access, readFile, opendir, stat, writeFile} from "fs/promises"
import ini from "ini"
import envPaths from "env-paths"
import chalk from "chalk"
import {isAbsolute, join, normalize, basename, sep} from "path"
import {moveFile} from "move-file"
import isValidFilename from "valid-filename"
import makeDir from "make-dir"
import homeDir from "home-dir"
import "source-map-support/register"
import defaultData from "./default-data.json"
import packageData from "./package.json"
import buildTimestamp from "consts:buildTimestamp"
import configName from "consts:configName"

const {Toggle, Select, Input, AutoComplete} = enquirer
const {R_OK, W_OK} = fsConstants

function log(message) {
    process.stderr.write(message + "\n")
}

function validateFilenamePart(part, {allowEmpty = false} = {}) {
    if (typeof part !== "string") {
        return `must be a string, but was ${part === null ? "null" : typeof part}`
    }
    if (part.length === 0) {
        if (allowEmpty) {
            return true
        } else {
            return "must not be empty, but was empty"
        }
    }
    if (!isValidFilename(part + ".save")) {
        return `cannot contain any of the following characters: <>:"/\\|?*`
    }
    return true
}

const DIRECTORY_OK = "OK"
const DIRECTORY_EMPTY = "Path is empty"
const DIRECTORY_NOT_ABSOLUTE = "Path must be absolute"
const DIRECTORY_NOT_VALID = "Path must contain segments which are valid filenames"
const DIRECTORY_EXISTS_NOT_DIRECTORY = "Path exists, but is not a directory"
const DIRECTORY_NOT_EXISTS = "Path does not exist"
const DIRECTORY_NOT_ACCESSIBLE = "Path is a directory, but is not both readable and writable"

function validatePath(path) {
    if (typeof path !== "string" || path.length === 0) {
        return DIRECTORY_EMPTY
    } else if (!isAbsolute(path)) {
        return DIRECTORY_NOT_ABSOLUTE
    } else if (!path.split(sep).slice(1).every(isValidFilename)) {
        return DIRECTORY_NOT_VALID
    }
    return DIRECTORY_OK
}

async function validateDirectory(path) {
    const pathValidity = validatePath(path)
    if (pathValidity !== DIRECTORY_OK) {
        return pathValidity
    }
    try {
        const statResult = await stat(path)
        if (!statResult.isDirectory()) {
            return DIRECTORY_EXISTS_NOT_DIRECTORY
        }
        await access(path, R_OK | W_OK)
    } catch (ex) {
        if (ex.code === "ENOENT") {
            return DIRECTORY_NOT_EXISTS
        } else if (ex.code === "EACCES") {
            return DIRECTORY_NOT_ACCESSIBLE
        } else {
            throw ex
        }
    }
    return DIRECTORY_OK
}

function validateRegExp(text) {
    if (typeof text !== "string") {
        return `must be a string, but was ${text === null ? "null" : typeof text}`
    }
    try {
        new RegExp(text)
        return true
    } catch (ex) {
        return `must be a valid regular expression, but couldn't construct a RegExp with it: ${ex}`
    }
}

function validateFilenamePartList(list, {minLength = 0, allowMissing = false} = {}) {
    if (typeof list === "undefined") {
        if (allowMissing) {
            return true
        } else {
            return `must be present, but was absent`
        }
    }
    if (!Array.isArray(list)) {
        return `must be an array, but was ${list === null ? typeof list : "null"}`
    }
    if (list.length < minLength) {
        return `must have at least ${minLength} ${minLength === 1 ? "element" : "elements"}, but had ${list.length}`
    }
    const firstNonmatching = list.findIndex((item) => !(typeof item === "string" && item.length > 0 && validateFilenamePart(item) === true))
    if (firstNonmatching !== -1) {
        return `element at index ${firstNonmatching} ${validateFilenamePart(list[firstNonmatching])}`
    }
    return true
}

function validateGameData(data) {
    if (typeof data !== "object" || data === null) {
        return `must be an object, but was ${typeof data}`
    }
    const fileRegExpError = validateRegExp(data.fileRegExp)
    if (validateRegExp(data.fileRegExp) !== true) {
        return `fileRegExp ${fileRegExpError}`
    }
    const charactersError = validateFilenamePartList(data.characters, {allowMissing: true})
    if (charactersError !== true) {
        return `characters ${charactersError}`
    }
    const timesError = validateFilenamePartList(data.times, {minLength: 1})
    if (timesError !== true) {
        return `times ${timesError}`
    }
    const voreRolesError = validateFilenamePartList(data.voreRoles, {minLength: 1})
    if (voreRolesError !== true) {
        return `voreRoles ${voreRolesError}`
    }
    const voreTypesError = validateFilenamePartList(data.voreTypes, {minLength: 1})
    if (voreTypesError !== true) {
        return `voreTypes ${voreTypesError}`
    }
    const voreResultsError = validateFilenamePartList(data.voreResults, {minLength: 1})
    if (voreResultsError !== true) {
        return `voreResults ${voreResultsError}`
    }
    const characterSceneTypesError = validateFilenamePartList(data.characterSceneTypes, {allowMissing: true})
    if (characterSceneTypesError !== true) {
        return `characterSceneTypes ${characterSceneTypesError}`
    }
    const otherSceneTypesError = validateFilenamePartList(data.otherSceneTypes, {allowMissing: true})
    if (otherSceneTypesError !== true) {
        return `otherSceneTypes ${otherSceneTypesError}`
    }
    return true
}

async function getDirectoryFromUser(message, initial) {
    let dirState = null
    let newDir = initial
    while (dirState !== DIRECTORY_OK) {
        newDir = normalize(await new Input({
            message,
            initial: newDir,
            validate: (text) => {
                const pathErr = validatePath(text)
                if (pathErr === DIRECTORY_OK) {
                    return true
                } else {
                    return pathErr
                }
            }
        }).run())
        try {
            dirState = await validateDirectory(newDir)
        } catch (ex) {
            log(chalk.red(`Couldn't check on that folder: ${chalk.redBright.bold(ex)}. Try again.`))
            dirState = null
        }
        if (dirState === DIRECTORY_NOT_EXISTS) {
            const create = await new Toggle({
                message: "That folder doesn't exist. Want me to create it?",
                enabled: "Yes, create it",
                disabled: "No, I'll enter the path again",
            }).run()
            if (create) {
                try {
                    await makeDir(newDir)
                    try {
                        dirState = await validateDirectory(newDir)
                        if (dirState !== DIRECTORY_OK) {
                            log(chalk.red(`Creating the new folder led to an unusable directory: ${chalk.redBright.bold(dirState)}. Try again.`))
                        }
                    } catch (ex) {
                        log(chalk.red(`Couldn't check on the new folder: ${chalk.redBright.bold(ex)}. Try again.`))
                    }
                } catch (ex) {
                    log(chalk.red(`Couldn't create that folder: ${chalk.redBright.bold(ex)}. Try again.`))
                }
            }
        } else if (dirState !== null && dirState !== DIRECTORY_OK) {
            log(chalk.red(`Can't use that folder: ${dirState}. Try again.`))
        }
    }
    return newDir
}

async function loadPaths(config, home) {
    let sourceDir = process.env.SMVA_SOURCE_DIR || null
    let destDir = process.env.SMVA_DEST_DIR || null
    const configPath = join(config, "smva-indexer.ini")
    if (!(sourceDir && destDir)) {
        try {
            const configText = await readFile(configPath, {encoding: "utf-8"})
            log(chalk.cyan(`Read configuration from ${chalk.cyanBright.bold(configPath)}`))
            const configIni = ini.parse(configText)
            if (!sourceDir && configIni.paths && configIni.paths.source) {
                sourceDir = configIni.paths.source
            }
            if (!destDir && configIni.paths && configIni.paths.dest) {
                destDir = configIni.paths.dest
            }
        } catch (ex) {
            if (ex.code !== "ENOENT") {
                log(chalk.red(`Failed to read configuration from ${chalk.redBright.bold(configPath)}: ${chalk.redBright.bold(ex)}`))
            }
        }
    }
    const sourceDirOK = (await validateDirectory(sourceDir)) === DIRECTORY_OK
    const destDirOK = (await validateDirectory(destDir)) === DIRECTORY_OK
    if (!(sourceDirOK && destDirOK)) {
        log(chalk.yellow(`Configuration at ${chalk.yellowBright.bold(configPath)} is missing, incomplete, or damaged. Configuring now.`))
        if (!sourceDirOK) {
            sourceDir = await getDirectoryFromUser(
                "Where are SMVA saves downloaded to? (e.g., your Downloads folder)",
                sourceDir || join(home, "Downloads"))
        }
        if (!destDirOK) {
            destDir = await getDirectoryFromUser(
                "Where do you want to store your organized SMVA saves? (e.g., your Documents folder)",
                destDir || join(home, "Documents", "SMVA Saves")
            )
        }
        try {
            await makeDir(config)
            await writeFile(configPath, ini.encode({paths: {source: sourceDir, dest: destDir}}), {encoding: "utf-8"})
            log(chalk.cyan(`Wrote configuration to ${chalk.cyanBright.bold(configPath)}`))
        } catch (ex) {
            log(chalk.red(`Could not write configuration to ${chalk.redBright.bold(configPath)}`))
        }
    }
    const dataPath = join(config, "game-data.json")
    let data = defaultData
    try {
        data = JSON.parse(await readFile(dataPath, {encoding: "utf-8"}))
        const err = validateGameData(data)
        if (err === true) {
            log(chalk.cyan(`Read game data from ${chalk.cyanBright.bold(dataPath)}`))
        } else {
            log(chalk.red(`${chalk.redBright.bold(dataPath)} had a problem: ${chalk.redBright.bold(err)}`))
            log(chalk.yellow(`Using default game data.`))
            data = defaultData
        }
    } catch (ex) {
        switch (ex.code) {
            case "ENOENT":
                log(chalk.yellow(`${chalk.yellowBright.bold(dataPath)} not found. Using default game data.`))
                try {
                    await writeFile(dataPath, JSON.stringify(defaultData, null, 4), {encoding: "utf-8"})
                    log(chalk.cyan(`Wrote default game data to ${chalk.cyanBright.bold(dataPath)}`))
                } catch (ex) {
                    log(chalk.red(`Could not write default game data to ${chalk.redBright.bold(dataPath)}: ${chalk.redBright.bold(ex)}`))
                }
                break
            default:
                log(chalk.red(`Could not read game data from ${chalk.redBright.bold(dataPath)}: ${chalk.redBright.bold(ex)}`))
                log(chalk.yellow(`Using default game data.`))
        }
    }
    return {sourceDir, destDir, data}
}

async function* watchNewSaves(sourceDir, sourceRegexpString) {
    const sourceRe = new RegExp(`^${sourceRegexpString}\$`)
    let resolveNext
    let nextPromise
    let active = true

    function makeNewPromise() {
        nextPromise = new Promise((resolve) => {
            resolveNext = (...args) => {
                makeNewPromise()
                resolve(...args)
            }
        })
    }

    makeNewPromise()

    watch(sourceDir, {}, (eventType, filename) => {
        if (eventType === "rename" && sourceRe.test(filename)) {
            resolveNext(filename)
        }
    })

    log(chalk.green(`Waiting for new saves with filenames like ${chalk.greenBright.bold(`/${sourceRegexpString}/`)} to appear in ${chalk.greenBright.bold(sourceDir)}`))

    while (true) {
        const next = await nextPromise
        if (next && active) {
            yield next
        }
    }
}

async function* findExistingSaves(sourceDir, sourceRegexpString) {
    const sourceRe = new RegExp(`^${sourceRegexpString}\$`)
    log(chalk.green(`Scanning for existing saves with filenames like ${chalk.greenBright.bold(`/${sourceRegexpString}/`)} in ${chalk.greenBright.bold(sourceDir)}`))
    const dir = await opendir(sourceDir)
    for await (const dirent of dir) {
        if (dirent.isFile() && sourceRe.test(dirent.name)) {
            yield dirent.name
        }
    }
    log(chalk.cyan(`Finished scanning for existing saves`))
}

async function promptForFilename({
                                     times,
                                     voreTypes,
                                     voreRoles,
                                     voreResults,
                                     characterSceneTypes,
                                     otherSceneTypes,
                                     characters
                                 }) {
    const saveType = await new AutoComplete({
        message: "What type of save is this?",
        limit: 10,
        choices: ["Useful Save", "Vore Scene", ...(Array.isArray(characterSceneTypes) && characterSceneTypes.length > 0 ? characterSceneTypes.map((item) => `${item} (Character Scene)`) : []), ...(Array.isArray(otherSceneTypes) && otherSceneTypes.length > 0 ? otherSceneTypes.map((item) => `${item} (Other Scene)`) : []), "Skip This Save"],
    }).run()
    const timePrompt = times.length > 1 ? new AutoComplete({
        message: "When is this save from?",
        limit: 10,
        choices: times
    }) : {
        async run() {
            return times[0]
        }
    }
    if (saveType === "Vore Scene") {
        const voreType = voreTypes.length > 1 ? await new AutoComplete({
            message: "What type of vore is involved in this save?",
            limit: 10,
            choices: voreTypes
        }).run() : voreTypes[0]
        const voreRole = voreRoles.length > 1 ? await new AutoComplete({
            message: "What role does the player play in this scene?",
            limit: 10,
            choices: voreRoles
        }).run() : voreRoles[0]
        const voreResult = voreResults.length > 1 ? await new AutoComplete({
            message: "What is the result of the vore?",
            limit: 10,
            choices: voreResults,
        }).run() : voreResults[0]
        const time = await timePrompt.run()
        const vorePartners = Array.isArray(characters) && characters.length > 0 ? await new AutoComplete({
            message: "Who is/are the partner(s) the player is with in this scene?",
            limit: 10,
            choices: characters,
            multiple: true,
        }).run() : []
        const voreVariant = await new Input({
            message: `What is the variant name/comment for this scene?${vorePartners.length > 0 ? " (leave blank to skip)" : ""}`,
            validate: (filename) => validateFilenamePart(filename, {allowEmpty: vorePartners.length > 0})
        }).run()
        return `${voreType} ${voreRole} - ${voreResult} - ${time} ${vorePartners.join(" + ")}${voreVariant ? vorePartners.length > 0 ? ` (${voreVariant})` : voreVariant : ""}.save`
    } else if (saveType === "Useful Save") {
        const time = await timePrompt.run()
        const title = await new Input({
            message: "What is the title of this useful save?",
            validate: validateFilenamePart
        }).run()
        return `Useful Saves - ${time} - ${title}.save`
    } else if (saveType.endsWith(" (Character Scene)")) {
        const sceneType = saveType.substring(0, saveType.length - " (Character Scene)".length)
        const time = await timePrompt.run()
        const scenePartners = Array.isArray(characters) && characters.length > 0 ? await new AutoComplete({
            message: "Who is/are the partner(s) the player is with in this scene?",
            limit: 10,
            choices: characters,
            multiple: true,
            validate: (list) => list.length > 0,
        }).run() : []
        const title = await new Input({
            message: `What is the comment for this ${sceneType} scene?`,
            validate: validateFilenamePart
        }).run()
        return `${sceneType} with ${scenePartners.join("+")} - ${time} - ${title}.save`
    } else if (saveType.endsWith(" (Other Scene)")) {
        const sceneType = saveType.substring(0, saveType.length - " (Other Scene)".length)
        const time = await timePrompt.run()
        const title = await new Input({
            message: `What is the comment for this ${sceneType} scene?`,
            validate: validateFilenamePart
        }).run()
        return `${sceneType} - ${time} - ${title}.save`
    } else {
        return null
    }
}

async function askIfOverwrite(destPath) {
    console.log(chalk.yellow(`A file named ${chalk.yellowBright.bold(destPath)} already exists.`))
    const result = await new Select({
        message: "What should we do?",
        choices: ["Skip it", "Rename it", "Overwrite it"]
    }).run()
    switch (result) {
        case "Skip it":
            return false
        case "Overwrite it":
            return true
        case "Rename it":
            return (await new Input({
                message: "What would you like to name the file?",
                initial: basename(destPath, ".save"),
                validate: (name) => name.length > 0 && isValidFilename(name) ? true : "must be a nonempty string not ending in trailing periods or containing any of the characters <>:\"/\\|?*"
            }).run()) + ".save"
    }
}

function queueMovingTo(destDir, filenameData) {
    let resolvePromise, rejectPromise
    const completionPromise = new Promise((resolve, reject) => {
        resolvePromise = resolve
        rejectPromise = reject
    })
    const filequeue = []
    let processingFiles = false
    let endAfterCompleting = false

    async function processFiles() {
        if (processingFiles) {
            return
        }
        processingFiles = true
        while (filequeue.length > 0) {
            const nextFile = filequeue[0]
            try {
                await access(nextFile)
            } catch (ex) {
                if (ex.code !== "ENOENT") {
                    log(chalk.red(`failed accessing ${chalk.redBright.bold(nextFile)}: ${chalk.redBright.bold(ex)}`))
                }
                filequeue.shift()
                continue
            }
            log(chalk.green(`For save ${chalk.greenBright.bold(nextFile)}:`))
            const destFilename = await promptForFilename(filenameData)
            if (!destFilename) {
                log(chalk.yellow("Skipped."))
                filequeue.shift()
                continue
            }
            let destPath = join(destDir, destFilename)
            let overwrite = false
            while (true) {
                try {
                    await moveFile(nextFile, destPath, {overwrite})
                    log(chalk.cyan(`Moved to ${chalk.cyanBright.bold(destPath)}`))
                    break
                } catch (ex) {
                    if (ex.message.startsWith("The destination file exists:")) {
                        const promptResult = await askIfOverwrite(destPath)
                        if (typeof promptResult === "string") {
                            destPath = join(destDir, promptResult)
                        } else if (promptResult === true) {
                            overwrite = true
                        } else {
                            break
                        }
                    } else {
                        log(chalk.red(`Something went wrong: ${chalk.redBright.bold(ex)}`))
                        const giveUp = await new Toggle({
                            message: "Want to keep trying?",
                            disabled: "Yes, try again",
                            enabled: "No, skip this save"
                        }).run()
                        if (giveUp) {
                            break
                        }
                    }
                }
            }
            filequeue.shift()
        }
        processingFiles = false
        if (endAfterCompleting) {
            resolvePromise()
        }
    }

    log(chalk.green(`Ready to move renamed saves to ${chalk.greenBright.bold(destDir)}`))

    return {
        push(...files) {
            if (!rejectPromise) {
                throw Error("Already stopped the queue")
            }
            for (const file of files) {
                if (!filequeue.includes(file)) {
                    filequeue.push(file)
                }
            }
            processFiles().catch((err) => {
                if (!rejectPromise) {
                    return
                }
                rejectPromise(err)
                resolvePromise = null
                rejectPromise = null
            })
        },
        shutDown() {
            if (!resolvePromise) {
                return
            }
            if (processingFiles) {
                endAfterCompleting = true
            } else {
                resolvePromise()
            }
        },
        completionPromise
    }
}

export async function main() {
    log(chalk.green(`${packageData.name} ${chalk.greenBright.bold(`v${packageData.version}`)} - built at ${chalk.greenBright.bold(new Date(buildTimestamp).toISOString())}`))
    const {config} = envPaths(configName)
    const home = homeDir()
    const {
        sourceDir,
        destDir,
        data: {fileRegExp, ...filenameData}
    } = await loadPaths(config, home)
    const queue = queueMovingTo(destDir, filenameData)

    const existingSavesPromise = (async () => {
        try {
            for await (const oldSave of findExistingSaves(sourceDir, fileRegExp)) {
                queue.push(join(sourceDir, oldSave))
            }
        } catch (ex) {
            log(chalk.red(`failed searching for existing saves: ${chalk.redBright.bold(ex)}`))
        }
    })()

    const newSavesPromise = (async () => {
        try {
            for await (const newSave of watchNewSaves(sourceDir, fileRegExp)) {
                queue.push(join(sourceDir, newSave))
            }
        } catch (ex) {
            log(chalk.red(`failed waiting for new saves: ${chalk.redBright.bold(ex)}`))
        }
    })()
    Promise.allSettled([newSavesPromise, existingSavesPromise]).finally(() => queue.shutDown())
    try {
        await queue.completionPromise
    } catch (err) {
        console.log(chalk.redBright.bold(err))
        process.exit(1)
    }
    process.exit(0)
}

main.packageName = packageData.name
main.version = packageData.version
main.buildTimestamp = packageData.buildTimestamp