/*
 * Copyright (C) 2025 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.eyedropper.ui.utils

import androidx.compose.runtime.Composable
import androidx.compose.runtime.remember
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.geometry.Rect
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.ImageBitmap
import androidx.compose.ui.res.colorResource
import androidx.compose.ui.res.dimensionResource
import androidx.compose.ui.res.integerResource
import androidx.compose.ui.unit.Density
import androidx.compose.ui.unit.Dp
import com.android.eyedropper.R
import com.android.eyedropper.ui.utils.ComposableDrawableLoader.drawableToBitmap

const val ARROW_PADDING_PX = 20f // Distance from inner circle edge to arrow center
const val ARROW_TOUCH_SLOP_PX = 12f // Expand touch target for easier tapping
const val LONG_PRESS_MOVE_PX = 10

enum class ReticleDirectionButton {
    UP, DOWN, LEFT, RIGHT
}

// Data class to hold pre-loaded resources and pixel dimensions
data class ReticleProps(
    val reticleBackgroundBitmap: ImageBitmap,
    val reticleOutlineBitmap: ImageBitmap,
    val handleBitmap: ImageBitmap,
    val arrowUpBitmap: ImageBitmap,
    val arrowDownBitmap: ImageBitmap,
    val arrowLeftBitmap: ImageBitmap,
    val arrowRightBitmap: ImageBitmap,
    val reticleBackgroundWidthPx: Float,
    val reticleBackgroundHeightPx: Float,
    val reticleInnerCircleSizePx: Float,
    val reticleRingWidthPx: Float,
    val handleMarginTopPx: Float,
    val handleMarginBottomPx: Float,
    val handleWidthPx: Float,
    val handleHeightPx: Float,
    val googleGrey400: Color,
    val containerColor: Color,
    val reticleInnerOutlineStrokeWidthPx: Float,
    val reticleToScreenBorderMinPadding: Float,
    val magnifiedPatchNumPx: Int,
    val keyMoveAmountPx: Int,
)

// Composable to load and remember ReticleDrawData
@Composable
fun getReticleDrawProps(density: Density): ReticleProps {
    // Load bitmaps
    val reticleBackgroundBitmap = drawableToBitmap(R.drawable.magnify_background)
    val reticleOutlineBitmap = drawableToBitmap(R.drawable.magnify_background_outline)
    val handleBitmap = drawableToBitmap(R.drawable.reticle_handle)
    val arrowUpBitmap = drawableToBitmap(R.drawable.reticle_up_arrow)
    val arrowDownBitmap = drawableToBitmap(R.drawable.reticle_down_arrow)
    val arrowLeftBitmap = drawableToBitmap(R.drawable.reticle_left_arrow)
    val arrowRightBitmap = drawableToBitmap(R.drawable.reticle_right_arrow)

    val reticleBackgroundWidthPx = dimensionResource(
        R.dimen.reticle_magnify_view_background_width
    ).toPx(density)
    val reticleBackgroundHeightPx = dimensionResource(
        R.dimen.reticle_magnify_view_background_height
    ).toPx(density)

    val reticleInnerCircleSizePx = dimensionResource(
        R.dimen.reticle_magnify_view_inner_circle_size
    ).toPx(density)
    val reticleRingWidthPx = dimensionResource(
        R.dimen.reticle_magnify_view_outer_ring_width
    ).toPx(density)

    val handleMarginTopPx = dimensionResource(R.dimen.reticle_handle_view_margin_top).toPx(density)
    val handleMarginBottomPx = dimensionResource(
        R.dimen.reticle_handle_view_margin_bottom
    ).toPx(density)

    val handleWidthPx = handleBitmap.width.toFloat()
    val handleHeightPx = handleBitmap.height.toFloat()

    val googleGrey400 = colorResource(R.color.google_grey400)
    val containerColor = colorResource(R.color.screenshot_image_view_container_bg_color)
    val reticleInnerOutlineStrokeWidthPx = dimensionResource(
        R.dimen.reticle_handle_view_inner_outline_stroke_width
    ).toPx(density)

    val magnifiedPatchNumPx = integerResource(R.integer.touchscreen_magnified_patch_num_px)
    val reticleToScreenBorderMinPadding = dimensionResource(
        R.dimen.reticle_to_screen_border_min_padding
    ).toPx(density)
    val keyMoveAmountPx = integerResource(R.integer.key_move_amount_px)

    return remember(density) {
        ReticleProps(
            reticleBackgroundBitmap = reticleBackgroundBitmap,
            reticleOutlineBitmap = reticleOutlineBitmap,
            handleBitmap = handleBitmap,
            arrowUpBitmap = arrowUpBitmap,
            arrowDownBitmap = arrowDownBitmap,
            arrowLeftBitmap = arrowLeftBitmap,
            arrowRightBitmap = arrowRightBitmap,

            reticleBackgroundWidthPx = reticleBackgroundWidthPx,
            reticleBackgroundHeightPx = reticleBackgroundHeightPx,

            reticleInnerCircleSizePx = reticleInnerCircleSizePx,
            reticleInnerOutlineStrokeWidthPx = reticleInnerOutlineStrokeWidthPx,
            reticleRingWidthPx = reticleRingWidthPx,
            magnifiedPatchNumPx = magnifiedPatchNumPx,

            handleMarginTopPx = handleMarginTopPx,
            handleMarginBottomPx = handleMarginBottomPx,
            handleWidthPx = handleWidthPx,
            handleHeightPx = handleHeightPx,

            googleGrey400 = googleGrey400,
            containerColor = containerColor,

            reticleToScreenBorderMinPadding = reticleToScreenBorderMinPadding,
            keyMoveAmountPx = keyMoveAmountPx,
        )
    }
}

/**
 * Get coordinates for the rectangular bounding box around the reticle at [displayedPointerPosition]
 */
fun getReticleTotalBounds(displayedPointerPosition: Offset, drawProps: ReticleProps): Rect {
    val handleTopY = displayedPointerPosition.y - drawProps.handleHeightPx / 2f
    val reticleBackgroundTopY = handleTopY - drawProps.handleMarginBottomPx -
            drawProps.handleMarginTopPx - drawProps.reticleBackgroundHeightPx

    val left = displayedPointerPosition.x - drawProps.reticleBackgroundWidthPx / 2f
    val right = displayedPointerPosition.x + drawProps.reticleBackgroundWidthPx / 2f
    val top = reticleBackgroundTopY
    val bottom = displayedPointerPosition.y + drawProps.handleHeightPx / 2f

    return Rect(left, top, right, bottom)
}

/**
 * Check if the tap at [this] is within the touch target region for the [direction] arrow.
 */
fun Offset.isWithinArrow(
    direction: ReticleDirectionButton,
    bitmap: ImageBitmap,
    innerCircleCenter: Offset,
    placementRadius: Int,
): Boolean {
    val width = bitmap.width
    val height = bitmap.height
    val topLeft = innerCircleCenter.getArrowPositionAroundCenter(
        direction,
        width / 2,
        placementRadius
    )
    val touchArea = Rect(
        topLeft.x - ARROW_TOUCH_SLOP_PX,
        topLeft.y - ARROW_TOUCH_SLOP_PX,
        topLeft.x + width + ARROW_TOUCH_SLOP_PX,
        topLeft.y + height + ARROW_TOUCH_SLOP_PX
    )
    return touchArea.contains(this)
}

/**
 * Get the top left position the [direction] arrow should be placed
 */
fun Offset.getArrowPositionAroundCenter(
    direction: ReticleDirectionButton,
    itemRadius: Int,
    arcRadius: Int
): Offset {
    val topLeftPos = when (direction) {
        ReticleDirectionButton.UP -> this.copy(y = this.y - arcRadius)
        ReticleDirectionButton.DOWN -> this.copy(y = this.y + arcRadius)
        ReticleDirectionButton.LEFT -> this.copy(x = this.x - arcRadius)
        ReticleDirectionButton.RIGHT -> this.copy(x = this.x + arcRadius)
    }
    return Offset(topLeftPos.x - itemRadius, topLeftPos.y - itemRadius)
}

fun Dp.toPx(density: Density): Float = with(density) { this@toPx.toPx() }