/* 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.display

import android.content.Context
import android.graphics.Color
import android.graphics.Typeface
import android.graphics.drawable.Drawable
import android.util.TypedValue
import android.view.View
import android.view.accessibility.AccessibilityEvent
import android.widget.ImageView
import android.widget.ProgressBar
import androidx.annotation.ColorInt
import androidx.annotation.VisibleForTesting
import androidx.appcompat.content.res.AppCompatResources.getDrawable
import androidx.constraintlayout.widget.ConstraintLayout
import androidx.constraintlayout.widget.ConstraintSet
import androidx.core.content.ContextCompat
import androidx.core.view.isVisible
import mozilla.components.browser.menu.BrowserMenuBuilder
import mozilla.components.browser.toolbar.BrowserToolbar
import mozilla.components.browser.toolbar.R
import mozilla.components.browser.toolbar.internal.ActionContainer
import mozilla.components.concept.menu.MenuController
import mozilla.components.concept.toolbar.Toolbar

/**
 * Sub-component of the browser toolbar responsible for displaying the URL and related controls ("display mode").
 *
 * Structure:
 * ```
 *   +-------------+------------+-----------------------+----------+------+
 *   | navigation  | indicators | url       [ page    ] | browser  | menu |
 *   |   actions   |            |           [ actions ] | actions  |      |
 *   +-------------+------------+-----------------------+----------+------+
 *   +------------------------progress------------------------------------+
 * ```
 *
 * Navigation actions (optional):
 *     A dynamic list of clickable icons usually used for navigation on larger devices
 *     (e.g. “back”/”forward” buttons.)
 *
 * Indicators (optional):
 *     Tracking protection indicator icon (e.g. “shield” icon) that may show a doorhanger when clicked.
 *     Separator icon: a vertical line that separate the above and below icons.
 *     Site security indicator icon (e.g. “Lock” icon) that may show a doorhanger when clicked.
 *     Empty indicator: Icon that will be displayed if the URL is empty.
 *
 * URL:
 *     Section that displays the current URL (read-only)
 *
 * Page actions (optional):
 *     A dynamic list of clickable icons inside the URL section (e.g. “reader mode” icon)
 *
 * Browser actions (optional):
 *     A list of dynamic clickable icons on the toolbar (e.g. tabs tray button)
 *
 * Menu (optional):
 *     A button that shows an overflow menu when clicked (constructed using the browser-menu
 *     component)
 *
 * Progress (optional):
 *     A horizontal progress bar showing the loading progress (at the top or bottom of the toolbar).
 */
@Suppress("LargeClass", "TooManyFunctions")
class DisplayToolbar internal constructor(
    private val context: Context,
    private val toolbar: BrowserToolbar,
    internal val rootView: View
) {
    /**
     * Enum of indicators that can be displayed in the toolbar.
     */
    enum class Indicators {
        SECURITY,
        TRACKING_PROTECTION,
        EMPTY
    }

    /**
     * Data class holding the customizable colors in "display mode".
     *
     * @property securityIconSecure Color tint for the "secure connection" icon (lock).
     * @property securityIconInsecure Color tint for the "insecure connection" icon (broken lock).
     * @property emptyIcon Color tint for the icon shown when the URL is empty.
     * @property menu Color tint for the menu icon.
     * @property hint Text color of the hint shown when the URL is empty.
     * @property title Text color of the website title.
     * @property text Text color of the URL.
     * @property trackingProtection Color tint for the tracking protection icons.
     * @property separator Color tint for the separator shown between indicators.
     *
     * Set/Get the site security icon colours. It uses a pair of color integers which represent the
     * insecure and secure colours respectively.
     */
    data class Colors(
        @ColorInt val securityIconSecure: Int,
        @ColorInt val securityIconInsecure: Int,
        @ColorInt val emptyIcon: Int,
        @ColorInt val menu: Int,
        @ColorInt val hint: Int,
        @ColorInt val title: Int,
        @ColorInt val text: Int,
        @ColorInt val trackingProtection: Int?,
        @ColorInt val separator: Int
    )

    /**
     * Data class holding the customizable icons in "display mode".
     *
     * @property emptyIcon An icon that is shown in front of the URL if the URL is empty.
     * @property trackingProtectionTrackersBlocked An icon that is shown if tracking protection is
     * enabled and trackers have been blocked.
     * @property trackingProtectionNothingBlocked An icon that is shown if tracking protection is
     * enabled and no trackers have been blocked.
     * @property trackingProtectionException An icon that is shown if tracking protection is enabled
     * but the current page is in the "exception list".
     */
    data class Icons(
        val emptyIcon: Drawable?,
        val trackingProtectionTrackersBlocked: Drawable,
        val trackingProtectionNothingBlocked: Drawable,
        val trackingProtectionException: Drawable
    )

    /**
     * Gravity enum for positioning the progress bar.
     */
    enum class Gravity {
        TOP,
        BOTTOM
    }

    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
    internal val views = DisplayToolbarViews(
        browserActions = rootView.findViewById(R.id.mozac_browser_toolbar_browser_actions),
        pageActions = rootView.findViewById(R.id.mozac_browser_toolbar_page_actions),
        navigationActions = rootView.findViewById(R.id.mozac_browser_toolbar_navigation_actions),
        background = rootView.findViewById(R.id.mozac_browser_toolbar_background),
        separator = rootView.findViewById(R.id.mozac_browser_toolbar_separator),
        emptyIndicator = rootView.findViewById(R.id.mozac_browser_toolbar_empty_indicator),
        menu = MenuButton(rootView.findViewById(R.id.mozac_browser_toolbar_menu)),
        securityIndicator = rootView.findViewById(R.id.mozac_browser_toolbar_security_indicator),
        trackingProtectionIndicator = rootView.findViewById(
            R.id.mozac_browser_toolbar_tracking_protection_indicator
        ),
        origin = rootView.findViewById<OriginView>(R.id.mozac_browser_toolbar_origin_view).also {
            it.toolbar = toolbar
        },
        progress = rootView.findViewById<ProgressBar>(R.id.mozac_browser_toolbar_progress).apply {
            accessibilityDelegate = object : View.AccessibilityDelegate() {
                override fun onInitializeAccessibilityEvent(host: View?, event: AccessibilityEvent?) {
                    super.onInitializeAccessibilityEvent(host, event)
                    if (event?.eventType == AccessibilityEvent.TYPE_VIEW_SCROLLED) {
                        // Populate the scroll event with the current progress.
                        // See accessibility note in `updateProgress()`.
                        event.scrollY = progress
                        event.maxScrollY = max
                    }
                }
            }
        }
    )

    /**
     * Customizable colors in "display mode".
     */
    var colors: Colors = Colors(
        securityIconSecure = ContextCompat.getColor(context, R.color.photonWhite),
        securityIconInsecure = ContextCompat.getColor(context, R.color.photonWhite),
        emptyIcon = ContextCompat.getColor(context, R.color.photonWhite),
        menu = ContextCompat.getColor(context, R.color.photonWhite),
        hint = views.origin.hintColor,
        title = views.origin.titleColor,
        text = views.origin.textColor,
        trackingProtection = null,
        separator = ContextCompat.getColor(context, R.color.photonGrey80)
    )
    set(value) {
        field = value

        updateSiteSecurityIcon()
        views.emptyIndicator.setColorFilter(value.emptyIcon)
        views.menu.setColorFilter(value.menu)
        views.origin.hintColor = value.hint
        views.origin.titleColor = value.title
        views.origin.textColor = value.text
        views.separator.setColorFilter(value.separator)

        if (value.trackingProtection != null) {
            views.trackingProtectionIndicator.setTint(value.trackingProtection)
            views.trackingProtectionIndicator.setColorFilter(value.trackingProtection)
        }
    }

    /**
     * Customizable icons in "edit mode".
     */
    var icons: Icons = Icons(
        emptyIcon = null,
        trackingProtectionTrackersBlocked = requireNotNull(
            getDrawable(context, TrackingProtectionIconView.DEFAULT_ICON_ON_TRACKERS_BLOCKED)
        ),
        trackingProtectionNothingBlocked = requireNotNull(
            getDrawable(context, TrackingProtectionIconView.DEFAULT_ICON_ON_NO_TRACKERS_BLOCKED)
        ),
        trackingProtectionException = requireNotNull(
            getDrawable(context, TrackingProtectionIconView.DEFAULT_ICON_OFF_FOR_A_SITE)
        )
    )
    set(value) {
        field = value

        views.emptyIndicator.setImageDrawable(value.emptyIcon)

        views.trackingProtectionIndicator.setIcons(
            value.trackingProtectionNothingBlocked,
            value.trackingProtectionTrackersBlocked,
            value.trackingProtectionException
        )
    }

    /**
    * Allows customization of URL for display purposes.
    */
    var urlFormatter: ((CharSequence) -> CharSequence)? = null

    /**
     * Sets a listener to be invoked when the site security indicator icon is clicked.
     */
    fun setOnSiteSecurityClickedListener(listener: (() -> Unit)?) {
        if (listener == null) {
            views.securityIndicator.setOnClickListener(null)
            views.securityIndicator.background = null
        } else {
            views.securityIndicator.setOnClickListener {
                listener.invoke()
            }

            val outValue = TypedValue()
            context.theme.resolveAttribute(
                android.R.attr.selectableItemBackgroundBorderless,
                outValue,
                true
            )

            views.securityIndicator.setBackgroundResource(outValue.resourceId)
        }
    }

    /**
     * Sets a listener to be invoked when the site tracking protection indicator icon is clicked.
     */
    fun setOnTrackingProtectionClickedListener(listener: (() -> Unit)?) {
        if (listener == null) {
            views.trackingProtectionIndicator.setOnClickListener(null)
            views.trackingProtectionIndicator.background = null
        } else {
            views.trackingProtectionIndicator.setOnClickListener {
                listener.invoke()
            }

            val outValue = TypedValue()
            context.theme.resolveAttribute(
                android.R.attr.selectableItemBackgroundBorderless,
                outValue,
                true
            )

            views.trackingProtectionIndicator.setBackgroundResource(outValue.resourceId)
        }
    }

    /**
     *  Sets a lambda to be invoked when the menu is dismissed
     */
    fun setMenuDismissAction(onDismiss: () -> Unit) {
        views.menu.setMenuDismissAction(onDismiss)
    }

    /**
     * List of indicators that should be displayed next to the URL.
     */
    var indicators: List<Indicators> = listOf(Indicators.SECURITY)
        set(value) {
            field = value

            updateIndicatorVisibility()
        }

    var displayIndicatorSeparator: Boolean = true
        set(value) {
            field = value
            updateIndicatorVisibility()
        }

    /**
     * Sets the background that should be drawn behind the URL, page actions an indicators.
     */
    fun setUrlBackground(background: Drawable?) {
        views.background.setImageDrawable(background)
    }

    /**
     * Whether the progress bar should be drawn at the top or bottom of the toolbar.
     */
    var progressGravity: Gravity = Gravity.BOTTOM
        set(value) {
            field = value

            val layout = rootView as ConstraintLayout
            layout.hashCode()

            val constraintSet = ConstraintSet()
            constraintSet.clone(layout)
            constraintSet.clear(views.progress.id, ConstraintSet.TOP)
            constraintSet.clear(views.progress.id, ConstraintSet.BOTTOM)
            constraintSet.connect(
                views.progress.id,
                if (value == Gravity.TOP) ConstraintSet.TOP else ConstraintSet.BOTTOM,
                ConstraintSet.PARENT_ID,
                if (value == Gravity.TOP) ConstraintSet.TOP else ConstraintSet.BOTTOM
            )
            constraintSet.applyTo(layout)
        }

    /**
     * Sets a lambda that will be invoked whenever the URL in display mode was clicked. Only if this
     * lambda returns <code>true</code> the toolbar will switch to editing mode. Return
     * <code>false</code> to not switch to editing mode and handle the click manually.
     */
    var onUrlClicked: () -> Boolean
        get() = views.origin.onUrlClicked
        set(value) {
            views.origin.onUrlClicked = value
        }

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

    /**
     * Sets the size of the text for the title displayed in the toolbar.
     */
    var titleTextSize: Float
        get() = views.origin.titleTextSize
        set(value) {
            views.origin.titleTextSize = value
        }

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

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

    /**
     * Sets a [BrowserMenuBuilder] that will be used to create a menu when the menu button is clicked.
     * The menu button will only be visible if a builder or controller has been set.
     */
    var menuBuilder: BrowserMenuBuilder?
        get() = views.menu.menuBuilder
        set(value) {
            views.menu.menuBuilder = value
        }

    /**
     * Sets a [MenuController] that will be used to create a menu when the menu button is clicked.
     * The menu button will only be visible if a builder or controller has been set.
     * If both a [menuBuilder] and controller are present, only the controller will be used.
     */
    var menuController: MenuController?
        get() = views.menu.menuController
        set(value) {
            views.menu.menuController = value
        }

    /**
     * Set a LongClickListener to the urlView of the toolbar.
     */
    fun setOnUrlLongClickListener(handler: ((View) -> Boolean)?) = views.origin.setOnUrlLongClickListener(handler)

    private fun updateIndicatorVisibility() {
        val urlEmpty = url.isEmpty()

        views.securityIndicator.visibility = if (!urlEmpty && indicators.contains(Indicators.SECURITY)) {
            View.VISIBLE
        } else {
            View.GONE
        }

        views.trackingProtectionIndicator.visibility = if (
            !urlEmpty && indicators.contains(Indicators.TRACKING_PROTECTION)
        ) {
            View.VISIBLE
        } else {
            View.GONE
        }

        views.emptyIndicator.visibility = if (urlEmpty && indicators.contains(Indicators.EMPTY)) {
            View.VISIBLE
        } else {
            View.GONE
        }

        updateSeparatorVisibility()
    }

    private fun updateSeparatorVisibility() {
        views.separator.visibility = if (
            displayIndicatorSeparator &&
            views.trackingProtectionIndicator.isVisible &&
            views.securityIndicator.isVisible
        ) {
            View.VISIBLE
        } else {
            View.GONE
        }

        // In Fenix (which is using a beta release of ConstraintLayout) we are seeing issues after
        // early visibility changes. Children of the ConstraintLayout are not visible and have a
        // size of 0x0 (even though they have a fixed size in the layout XML). Explicitly requesting
        // to layout the ConstraintLayout fixes that issue. This may be a bug in the beta of
        // ConstraintLayout and in the future we may be able to just remove this call.
        rootView.requestLayout()
    }

    /**
     * Updates the title to be displayed.
     */
    internal var title: String
        get() = views.origin.title
        set(value) {
            views.origin.title = value
        }

    /**
     * Updates the URL to be displayed.
     */
    internal var url: CharSequence = ""
        set(value) {
            field = value
            views.origin.url = urlFormatter?.invoke(value) ?: value
            updateIndicatorVisibility()
        }

    /**
     * Sets the site's security icon as secure if true, else the regular globe.
     */
    internal var siteSecurity: Toolbar.SiteSecurity = Toolbar.SiteSecurity.INSECURE
        set(value) {
            field = value
            updateSiteSecurityIcon()
        }

    private fun updateSiteSecurityIcon() {
        @ColorInt val color = when (siteSecurity) {
            Toolbar.SiteSecurity.INSECURE -> colors.securityIconInsecure
            Toolbar.SiteSecurity.SECURE -> colors.securityIconSecure
            Toolbar.SiteSecurity.ONION -> colors.securityIconSecure
        }
        if (color == Color.TRANSPARENT) {
            views.securityIndicator.clearColorFilter()
        } else {
            views.securityIndicator.setColorFilter(color)
        }

        views.securityIndicator.siteSecurity = siteSecurity
    }

    internal fun setTrackingProtectionState(state: Toolbar.SiteTrackingProtection) {
        if (!indicators.contains(Indicators.TRACKING_PROTECTION)) {
            return
        }

        views.trackingProtectionIndicator.siteTrackingProtection = state
        updateSeparatorVisibility()
    }

    internal fun onStop() {
        views.menu.dismissMenu()
    }

    /**
     * Updates the progress to be displayed.
     *
     * Accessibility note:
     *     ProgressBars can be made accessible to TalkBack by setting `android:accessibilityLiveRegion`.
     *     They will emit TYPE_VIEW_SELECTED events. TalkBack will format those events into percentage
     *     announcements along with a pitch-change earcon. We are not using that feature here for
     *     several reasons:
     *     1. They are dispatched via a 200ms timeout. Since loading a page can be a short process,
     *        and since we only update the bar a handful of times, these events often never fire and
     *        they don't give the user a true sense of the progress.
     *     2. The last 100% event is dispatched after the view is hidden. This prevents the event
     *        from being fired, so the user never gets a "complete" event.
     *     3. Live regions in TalkBack have their role announced, so the user will hear
     *        "Progress bar, 25%". For a common feature like page load this is very chatty and unintuitive.
     *     4. We can provide custom strings instead of the less useful percentage utterance, but
     *        TalkBack will not play an earcon if an event has its own text.
     *
     *     For all those reasons, we are going another route here with a "loading" announcement
     *     when the progress bar first appears along with scroll events that have the same
     *     pitch-change earcon in TalkBack (although they are a bit louder). This gives a concise and
     *     consistent feedback to the user that they can depend on.
     *
     */
    internal fun updateProgress(progress: Int) {
        if (!views.progress.isVisible && progress > 0) {
            // Loading has just started, make visible and announce "loading" for accessibility.
            views.progress.visibility = View.VISIBLE
            views.progress.announceForAccessibility(
                context.getString(R.string.mozac_browser_toolbar_progress_loading))
        }

        views.progress.progress = progress
        views.progress.sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_SCROLLED)

        if (progress >= views.progress.max) {
            // Loading is done, hide progress bar.
            views.progress.visibility = View.GONE
        }
    }

    /**
     * Declare that the actions (navigation actions, browser actions, page actions) have changed and
     * should be updated if needed.
     */
    internal fun invalidateActions() {
        views.menu.invalidateMenu()

        views.browserActions.invalidateActions()
        views.pageActions.invalidateActions()
        views.navigationActions.invalidateActions()
    }

    /**
     * Adds an action to be displayed on the right side of the toolbar (outside of the URL bounding
     * box) in display mode.
     *
     * If there is not enough room to show all icons then some icons may be moved to an overflow
     * menu.
     *
     * Related:
     * https://developer.mozilla.org/en-US/Add-ons/WebExtensions/user_interface/Browser_action
     */
    internal fun addBrowserAction(action: Toolbar.Action) {
        views.browserActions.addAction(action)
    }

    /**
     * Removes a previously added browser action (see [addBrowserAction]). If the provided
     * action was never added, this method has no effect.
     *
     * @param action the action to remove.
     */
    internal fun removeBrowserAction(action: Toolbar.Action) {
        views.browserActions.removeAction(action)
    }

    /**
     * Removes a previously added page action (see [addBrowserAction]). If the provided
     * action was never added, this method has no effect.
     *
     * @param action the action to remove.
     */
    internal fun removePageAction(action: Toolbar.Action) {
        views.pageActions.removeAction(action)
    }

    /**
     * Adds an action to be displayed on the right side of the URL in display mode.
     *
     * Related:
     * https://developer.mozilla.org/en-US/Add-ons/WebExtensions/user_interface/Page_actions
     */
    internal fun addPageAction(action: Toolbar.Action) {
        views.pageActions.addAction(action)
    }

    /**
     * Adds an action to be display on the far left side of the toolbar. This area is usually used
     * on larger devices for navigation actions like "back" and "forward".
     */
    internal fun addNavigationAction(action: Toolbar.Action) {
        views.navigationActions.addAction(action)
    }
}

/**
 * Internal holder for view references.
 */
internal class DisplayToolbarViews(
    val browserActions: ActionContainer,
    val pageActions: ActionContainer,
    val navigationActions: ActionContainer,
    val background: ImageView,
    val separator: ImageView,
    val emptyIndicator: ImageView,
    val menu: MenuButton,
    val securityIndicator: SiteSecurityIconView,
    val trackingProtectionIndicator: TrackingProtectionIconView,
    val origin: OriginView,
    val progress: ProgressBar
)
