/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package mozilla.components.browser.toolbar.edit

import android.content.Context
import android.graphics.Typeface
import android.graphics.drawable.Drawable
import android.view.KeyEvent
import android.view.View
import android.widget.ImageView
import androidx.annotation.ColorInt
import androidx.annotation.VisibleForTesting
import androidx.annotation.VisibleForTesting.Companion.PRIVATE
import androidx.constraintlayout.widget.ConstraintLayout
import androidx.constraintlayout.widget.ConstraintSet
import androidx.core.content.ContextCompat
import androidx.core.view.inputmethod.EditorInfoCompat
import androidx.core.view.isVisible
import kotlinx.coroutines.CoroutineExceptionHandler
import kotlinx.coroutines.SupervisorJob
import kotlinx.coroutines.asCoroutineDispatcher
import mozilla.components.browser.toolbar.AsyncFilterListener
import mozilla.components.browser.toolbar.BrowserToolbar
import mozilla.components.browser.toolbar.R
import mozilla.components.browser.toolbar.facts.emitCommitFact
import mozilla.components.browser.toolbar.internal.ActionContainer
import mozilla.components.concept.toolbar.AutocompleteDelegate
import mozilla.components.concept.toolbar.Toolbar
import mozilla.components.support.base.log.logger.Logger
import mozilla.components.support.base.utils.NamedThreadFactory
import mozilla.components.support.ktx.android.view.showKeyboard
import mozilla.components.ui.autocomplete.InlineAutocompleteEditText
import java.util.concurrent.Executors
import mozilla.components.ui.colors.R as colorsR

private const val AUTOCOMPLETE_QUERY_THREADS = 3

/**
 * Sub-component of the browser toolbar responsible for allowing the user to edit the URL ("edit mode").
 *
 * Structure:
 * +------+--------------------+---------------------------+------------------+------+
 * | icon | edit actions start |           url             | edit actions end | exit |
 * +------+--------------------+---------------------------+------------------+------+
 *
 * - icon: Optional icon that will be shown in front of the URL.
 * - edit actions start: Optional action icons injected by other components in front of the URL
 * (e.g. search engines).
 * - url: Editable URL of the currently displayed website.
 * - edit actions end: Optional action icons injected by other components after the URL
 * (e.g. barcode scanner).
 * - exit: Button that switches back to display mode or invoke an app-defined callback.
 */
@Suppress("LargeClass")
class EditToolbar internal constructor(
    context: Context,
    private val toolbar: BrowserToolbar,
    internal val rootView: View,
) {
    private val logger = Logger("EditToolbar")

    /**
     * Data class holding the customizable colors in "edit mode".
     *
     * @property clear Color tint used for the "cancel" icon to leave "edit mode".
     * @property icon Color tint of the icon displayed in front of the URL.
     * @property hint Text color of the hint shown when the URL field is empty.
     * @property text Text color of the URL.
     * @property suggestionBackground The background color used for autocomplete suggestions.
     * @property suggestionForeground The foreground color used for autocomplete suggestions.
     */
    data class Colors(
        @ColorInt val clear: Int,
        @ColorInt val icon: Int?,
        @ColorInt val hint: Int,
        @ColorInt val text: Int,
        @ColorInt val suggestionBackground: Int,
        @ColorInt val suggestionForeground: Int?,
    )

    private val autocompleteDispatcher = SupervisorJob() +
        Executors.newFixedThreadPool(
            AUTOCOMPLETE_QUERY_THREADS,
            NamedThreadFactory("EditToolbar"),
        ).asCoroutineDispatcher() +
        CoroutineExceptionHandler { _, throwable ->
            logger.error("Error while processing autocomplete input", throwable)
        }

    @VisibleForTesting(otherwise = PRIVATE)
    internal val views = EditToolbarViews(
        background = rootView.findViewById(R.id.mozac_browser_toolbar_background),
        icon = rootView.findViewById(R.id.mozac_browser_toolbar_edit_icon),
        editActionsStart = rootView.findViewById(R.id.mozac_browser_toolbar_edit_actions_start),
        editActionsEnd = rootView.findViewById(R.id.mozac_browser_toolbar_edit_actions_end),
        clear = rootView.findViewById<ImageView>(R.id.mozac_browser_toolbar_clear_view).apply {
            setOnClickListener {
                onClear()
            }
        },
        url = rootView.findViewById<InlineAutocompleteEditText>(
            R.id.mozac_browser_toolbar_edit_url_view,
        ).apply {
            setOnCommitListener {
                // We emit the fact before notifying the listener because otherwise the listener may cause a focus
                // change which may reset the autocomplete state that we want to report here.
                emitCommitFact(autocompleteResult)

                toolbar.onUrlEntered(text.toString())
            }

            setOnTextChangeListener { text, _ ->
                onTextChanged(text)
            }

            setUrlGoneMargin(
                ConstraintSet.END,
                context.resources.getDimensionPixelSize(R.dimen.mozac_browser_toolbar_url_gone_margin_end),
            )

            setOnDispatchKeyEventPreImeListener { event ->
                if (event?.keyCode == KeyEvent.KEYCODE_BACK && editListener?.onCancelEditing() != false) {
                    toolbar.displayMode()
                }
                false
            }
        },
    )

    /**
     * Customizable colors in "edit mode".
     */
    var colors: Colors = Colors(
        clear = ContextCompat.getColor(context, colorsR.color.photonWhite),
        icon = null,
        hint = views.url.currentHintTextColor,
        text = views.url.currentTextColor,
        suggestionBackground = views.url.autoCompleteBackgroundColor,
        suggestionForeground = views.url.autoCompleteForegroundColor,
    )
        set(value) {
            field = value

            views.clear.setColorFilter(value.clear)

            if (value.icon != null) {
                views.icon.setColorFilter(value.icon)
            }

            views.url.setHintTextColor(value.hint)
            views.url.setTextColor(value.text)
            views.url.autoCompleteBackgroundColor = value.suggestionBackground
            views.url.autoCompleteForegroundColor = value.suggestionForeground
        }

    /**
     * Sets the background that will be drawn behind the URL, icon and edit actions.
     */
    fun setUrlBackground(background: Drawable?) {
        views.background.setImageDrawable(background)
    }

    /**
     * Sets an icon that will be drawn in front of the URL.
     */
    fun setIcon(icon: Drawable, contentDescription: String) {
        views.icon.setImageDrawable(icon)
        views.icon.contentDescription = contentDescription
        views.icon.visibility = View.VISIBLE
    }

    /**
     * Sets a click listener on the icon view
     */
    fun setIconClickListener(listener: ((View) -> Unit)?) {
        views.icon.setOnClickListener(listener)
    }

    /**
     * Sets the text to be displayed when the URL of the toolbar is empty.
     */
    var hint: String
        get() = views.url.hint.toString()
        set(value) { views.url.hint = value }

    /**
     * Sets the size of the text for the URL/search term displayed in the toolbar.
     */
    var textSize: Float
        get() = views.url.textSize
        set(value) {
            views.url.textSize = value
        }

    /**
     * Sets the typeface of the text for the URL/search term displayed in the toolbar.
     */
    var typeface: Typeface
        get() = views.url.typeface
        set(value) { views.url.typeface = value }

    /**
     * Sets a listener to be invoked when focus of the URL input view (in edit mode) changed.
     */
    fun setOnEditFocusChangeListener(listener: (Boolean) -> Unit) {
        views.url.onFocusChangeListener = View.OnFocusChangeListener { _, hasFocus ->
            listener.invoke(hasFocus)
        }
    }

    /**
     * Focuses the url input field and shows the virtual keyboard if needed.
     */
    fun focus() {
        views.url.run {
            showKeyboard()
            requestFocus()
        }
    }

    internal fun stopEditing() {
        editListener?.onStopEditing()
    }

    internal fun startEditing() {
        editListener?.onStartEditing()
    }

    internal var editListener: Toolbar.OnEditListener? = null

    internal fun setAutocompleteListener(filter: suspend (String, AutocompleteDelegate) -> Unit) {
        views.url.setOnFilterListener(
            AsyncFilterListener(views.url, autocompleteDispatcher, filter),
        )
    }

    /**
     * Attempt to restart the autocomplete functionality with the current user input.
     */
    internal fun refreshAutocompleteSuggestion() {
        views.url.refreshAutocompleteSuggestions()
    }

    internal fun invalidateActions() {
        views.editActionsStart.invalidateActions()
        views.editActionsEnd.invalidateActions()
    }

    internal fun addEditActionStart(action: Toolbar.Action) {
        views.editActionsStart.addAction(action)
    }

    internal fun addEditActionEnd(action: Toolbar.Action) {
        views.editActionsEnd.addAction(action)
    }

    internal fun removeEditActionEnd(action: Toolbar.Action) {
        views.editActionsEnd.removeAction(action)
    }

    /**
     * Updates the text of the URL input field. Note: this does *not* affect the value of url itself
     * and is only a visual change
     */
    fun updateUrl(
        url: String,
        shouldAutoComplete: Boolean = false,
        shouldHighlight: Boolean = false,
        shouldAppend: Boolean = false,
    ): String {
        if (shouldAppend) {
            views.url.appendText(url, shouldAutoComplete)
        } else {
            views.url.setText(url, shouldAutoComplete)
        }
        views.clear.isVisible = url.isNotBlank()

        if (shouldHighlight) {
            views.url.setSelection(views.url.text.length - url.length, views.url.text.length)
        }
        return views.url.text.toString()
    }

    /**
     * Select the entire text in the URL input field.
     */
    internal fun selectAll() {
        views.url.selectAll()
    }

    /**
     * Places the cursor at the end of the URL input field.
     */
    internal fun selectEnd() {
        views.url.setSelection(views.url.text.length)
    }

    /**
     * Applies the given search terms for further editing, requesting new suggestions along the way.
     */
    internal fun editSuggestion(searchTerms: String) {
        updateUrl(searchTerms)
        views.url.setSelection(views.url.text.length)
        focus()

        editListener?.onTextChanged(searchTerms)
    }

    /**
     * Sets/gets private mode.
     *
     * In private mode the IME should not update any personalized data such as typing history and personalized language
     * model based on what the user typed.
     */
    internal var private: Boolean
        get() = (views.url.imeOptions and EditorInfoCompat.IME_FLAG_NO_PERSONALIZED_LEARNING) != 0
        set(value) {
            views.url.imeOptions = if (value) {
                views.url.imeOptions or EditorInfoCompat.IME_FLAG_NO_PERSONALIZED_LEARNING
            } else {
                views.url.imeOptions and (EditorInfoCompat.IME_FLAG_NO_PERSONALIZED_LEARNING.inv())
            }
        }

    private fun onClear() {
        // We set text to an empty string instead of using clear to avoid #3612.
        views.url.setText("")
    }

    private fun setUrlGoneMargin(anchor: Int, dimen: Int) {
        val set = ConstraintSet()
        val container = rootView.findViewById<ConstraintLayout>(
            R.id.mozac_browser_toolbar_container,
        )
        set.clone(container)
        set.setGoneMargin(R.id.mozac_browser_toolbar_edit_url_view, anchor, dimen)
        set.applyTo(container)
    }

    private fun onTextChanged(text: String) {
        views.clear.isVisible = text.isNotBlank()
        views.editActionsEnd.autoHideAction(text.isEmpty())

        /*
        We use margin_gone instead of margin to take into account both the actionContainer(which in
        most cases is gone) and the clear button.
         */
        if (text.isNotBlank()) {
            setUrlGoneMargin(ConstraintSet.END, 0)
        } else {
            setUrlGoneMargin(
                ConstraintSet.END,
                rootView.resources.getDimensionPixelSize(
                    R.dimen.mozac_browser_toolbar_url_gone_margin_end,
                ),
            )
        }
        editListener?.onTextChanged(text)
    }
}

/**
 * Internal holder for view references.
 */
internal class EditToolbarViews(
    val background: ImageView,
    val icon: ImageView,
    val editActionsStart: ActionContainer,
    val editActionsEnd: ActionContainer,
    val clear: ImageView,
    val url: InlineAutocompleteEditText,
)
