/*

 * AboutOss is an utility library to retrieve and display

 * opensource licenses in Android applications.

 *

 * Copyright (C) 2023 by Frederic-Charles Barthelery.

 *

 * This file is part of AboutOss.

 *

 * AboutOss 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.

 *

 * AboutOss 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 AboutOss.  If not, see <http://www.gnu.org/licenses/>.

 */

package com.geekorum.aboutoss.core.licenseplist

import kotlinx.cinterop.BetaInteropApi

import kotlinx.cinterop.ExperimentalForeignApi

import kotlinx.cinterop.ObjCObjectVar

import kotlinx.cinterop.alloc

import kotlinx.cinterop.memScoped

import kotlinx.cinterop.ptr

import kotlinx.cinterop.value

import platform.Foundation.NSBundle

import platform.Foundation.NSData

import platform.Foundation.NSError

import platform.Foundation.NSPropertyListMutableContainers

import platform.Foundation.NSPropertyListSerialization

import platform.Foundation.NSURL

import platform.Foundation.dataWithContentsOfURL

import kotlin.coroutines.resume

import kotlin.coroutines.resumeWithException

import kotlin.coroutines.suspendCoroutine

class LicensePlistParser {

    @Suppress("UNCHECKED_CAST")

    suspend fun parseLicenses(

        licensePlistInput: NSURL

    ): Map<String, String> {

        val fileContent = getContent(licensePlistInput)

        val plist = fileContent.toPropertyList() as Map<String, List<Map<String, String>>>

        val paneLists = plist["PreferenceSpecifiers"]!!

            .filter {

                it["Type"] == "PSChildPaneSpecifier"

            }

        val directoryUrl = licensePlistInput.URLByDeletingLastPathComponent()!!

        return paneLists.associate { pane ->

            val paneFile = pane["File"]!!

            val libraryName = pane["Title"]!!

            val paneUrl = buildPaneUrl(directoryUrl, paneFile)

            val paneFileContent =  getContent(paneUrl)

            val paneFilePlist = paneFileContent.toPropertyList() as Map<String, List<Map<String, String>>>

            val license = getLicenseFromPaneFilePlist(paneFilePlist)

            libraryName to license

        }

    }

    private fun buildPaneUrl(directoryUrl: NSURL, paneName: String) = directoryUrl.URLByAppendingPathComponent(paneName)!!.URLByAppendingPathExtension("plist")!!

    private fun getLicenseFromPaneFilePlist(paneFilePList: Map<String, List<Map<String, String>>>): String {

        val specifiers = paneFilePList["PreferenceSpecifiers"]!!

        val licenses = specifiers.map {

            it["FooterText"]!!

        }

        return licenses.joinToString("\n\n")

    }

    private fun getContent(url: NSURL): NSData {

        return checkNotNull(NSData.dataWithContentsOfURL(url))

    }

    @OptIn(ExperimentalForeignApi::class, BetaInteropApi::class)

    private suspend fun NSData.toPropertyList(): Any? = suspendCoroutine { cont ->

        val parsed = memScoped {

            val error: ObjCObjectVar<NSError?> = alloc()

            val result = NSPropertyListSerialization.propertyListWithData(this@toPropertyList,

                options = NSPropertyListMutableContainers,

                format = null,

                error.ptr

            )

            if (error.value != null) {

                cont.resumeWithException(Exception(error.value!!.description))

            }

            result

        }

        cont.resume(parsed!!)

    }

    companion object {

        fun getDefaultLicensePlistUrl(): NSURL {

            val path = NSBundle.mainBundle.pathForResource(

                "com.mono0926.LicensePlist",

                ofType = "plist",

                inDirectory = "licenseplist"

            )

            return NSURL.fileURLWithPath(path!!)

        }

    }

}