/* Copyright 2017 Andrew Dawson
 *
 * This file is a part of Tusky.
 *
 * 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.
 *
 * Tusky 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 Tusky; if not,
 * see <http://www.gnu.org/licenses>. */

package com.keylesspalace.tusky.pager

import android.util.SparseArray
import android.view.ViewGroup
import androidx.fragment.app.Fragment
import androidx.fragment.app.FragmentManager
import androidx.fragment.app.FragmentPagerAdapter
import androidx.viewpager.widget.PagerAdapter
import com.keylesspalace.tusky.TabData

class MainPagerAdapter(val tabs: List<TabData>, manager: FragmentManager) : FragmentPagerAdapter(manager) {
    private val fragments = SparseArray<Fragment>(tabs.size)

    override fun getItem(position: Int): Fragment {
        val tab = tabs[position]
        return tab.fragment(tab.arguments)
    }

    override fun getCount(): Int {
        return tabs.size
    }

    override fun getPageTitle(position: Int): CharSequence? {
        return null
    }

    override fun getItemId(position: Int): Long {
        return tabs[position].hashCode() + position.toLong()
    }

    override fun getItemPosition(item: Any): Int {
        return PagerAdapter.POSITION_NONE
    }

    override fun instantiateItem(container: ViewGroup, position: Int): Any {
        val fragment = super.instantiateItem(container, position)
        if (fragment is Fragment)
            fragments.put(position, fragment)
        return fragment
    }

    override fun destroyItem(container: ViewGroup, position: Int, `object`: Any) {
        super.destroyItem(container, position, `object`)
        fragments.remove(position)
    }

    fun getFragment(position: Int): Fragment? = fragments[position]
}