package org.openrndr.extra.composition

import org.openrndr.collections.pflatMap
import org.openrndr.collections.pforEach
import org.openrndr.color.ColorRGBa
import org.openrndr.draw.ColorBuffer
import org.openrndr.draw.LineCap
import org.openrndr.draw.LineJoin
import org.openrndr.math.Matrix44
import org.openrndr.math.Vector2
import org.openrndr.math.Vector3
import org.openrndr.math.YPolarity
import org.openrndr.math.transforms.*
import org.openrndr.shape.*

/**
 * Used internally to define [ClipMode]s.
 */
enum class ClipOp {
    DISABLED,
    DIFFERENCE,
    REVERSE_DIFFERENCE,
    INTERSECT,
    UNION
}

/**
 * Specifies if transformations should be kept separate
 * or applied to the clipped object and reset to identity.
 */
enum class TransformMode {
    KEEP,
    APPLY
}

/**
 * Specifies in which way to combine [Shape]s
 * to form a [Composition]
 */
enum class ClipMode(val grouped: Boolean, val op: ClipOp) {
    DISABLED(false, ClipOp.DISABLED),
    DIFFERENCE(false, ClipOp.DIFFERENCE),
    DIFFERENCE_GROUP(true, ClipOp.DIFFERENCE),
    REVERSE_DIFFERENCE(false, ClipOp.REVERSE_DIFFERENCE),
    REVERSE_DIFFERENCE_GROUP(true, ClipOp.REVERSE_DIFFERENCE),
    INTERSECT(false, ClipOp.INTERSECT),
    INTERSECT_GROUP(true, ClipOp.INTERSECT),
    UNION(false, ClipOp.UNION),
    UNION_GROUP(true, ClipOp.UNION)
}

/**
 * The set of draw style properties used for rendering a [Composition]
 */
private data class CompositionDrawStyle(
    var fill: ColorRGBa? = null,
    var fillOpacity: Double = 1.0,
    var stroke: ColorRGBa? = ColorRGBa.BLACK,
    var strokeOpacity: Double = 1.0,
    var strokeWeight: Double = 1.0,
    var opacity: Double = 1.0,
    var clipMode: ClipMode = ClipMode.DISABLED,
    var mask: Shape? = null,
    var transformMode: TransformMode = TransformMode.APPLY,
    var lineCap: LineCap = LineCap.BUTT,
    var lineJoin: LineJoin = LineJoin.MITER,
    var miterlimit: Double = 4.0,
    var visibility: Visibility = Visibility.Visible
)

/**
 * Data structure containing intersection information.
 */
data class ShapeNodeIntersection(val node: ShapeNode, val intersection: ContourIntersection)

/**
 * Data structure containing information about a point
 * in a [ShapeContour] closest to some other 2D point.
 */
data class ShapeNodeNearestContour(val node: ShapeNode, val point: ContourPoint, val distanceDirection: Vector2, val distance: Double)

/**
 * Merges two lists of [ShapeNodeIntersection] removing duplicates under the
 * given [threshold]. Used internally by [intersections].
 */
fun List<ShapeNodeIntersection>.merge(threshold: Double = 0.5): List<ShapeNodeIntersection> {
    val result = mutableListOf<ShapeNodeIntersection>()
    for (i in this) {
        val nearest = result.minByOrNull { it.intersection.position.squaredDistanceTo(i.intersection.position) }
        if (nearest == null) {
            result.add(i)
        } else if (nearest.intersection.position.squaredDistanceTo(i.intersection.position) >= threshold * threshold) {
            result.add(i)
        }
    }
    return result
}


/**
 * A Drawer-like interface for the creation of Compositions
 * This should be easier than creating Compositions manually
 */
class CompositionDrawer(documentBounds: CompositionDimensions = defaultCompositionDimensions,
                        composition: Composition? = null,
                        cursor: GroupNode? = composition?.root as? GroupNode
) {
    val root = (composition?.root as? GroupNode) ?: GroupNode()
    val composition = composition ?: Composition(root, documentBounds)

    var cursor = cursor ?: root
        private set

    private val modelStack = ArrayDeque<Matrix44>()
    private val styleStack = ArrayDeque<CompositionDrawStyle>().apply { }
    private var drawStyle = CompositionDrawStyle()

    var model = Matrix44.IDENTITY

    var fill
        get() = drawStyle.fill?.opacify(drawStyle.fillOpacity)?.opacify(drawStyle.opacity)
        set(value) = run {
            drawStyle.fill = value?.copy(alpha = 1.0)
            drawStyle.fillOpacity = value?.alpha ?: 1.0
        }

    var fillOpacity
        get() = drawStyle.fillOpacity
        set(value) = run { drawStyle.fillOpacity = value }

    var stroke
        get() = drawStyle.stroke?.opacify(drawStyle.strokeOpacity)?.opacify(drawStyle.opacity)
        set(value) = run {
            drawStyle.stroke = value?.copy(alpha = 1.0)
            drawStyle.strokeOpacity = value?.alpha ?: 1.0
        }

    var strokeOpacity
        get() = drawStyle.strokeOpacity
        set(value) = run { drawStyle.strokeOpacity = value }

    var strokeWeight
        get() = drawStyle.strokeWeight
        set(value) = run { drawStyle.strokeWeight = value }

    var miterlimit
        get() = drawStyle.miterlimit
        set(value) = run { drawStyle.miterlimit = value }

    var lineCap
        get() = drawStyle.lineCap
        set(value) = run { drawStyle.lineCap = value }

    var lineJoin
        get() = drawStyle.lineJoin
        set(value) = run { drawStyle.lineJoin = value }

    var opacity
        get() = drawStyle.opacity
        set(value) = run { drawStyle.opacity = value }

    var visibility
        get() = drawStyle.visibility
        set(value) = run { drawStyle.visibility = value }

    var clipMode
        get() = drawStyle.clipMode
        set(value) = run { drawStyle.clipMode = value }

    var mask: Shape?
        get() = drawStyle.mask
        set(value) = run { drawStyle.mask = value }

    var transformMode
        get() = drawStyle.transformMode
        set(value) = run { drawStyle.transformMode = value }

    fun pushModel() {
        modelStack.addLast(model)
    }

    fun popModel() {
        model = modelStack.removeLast()
    }

    fun pushStyle() {
        styleStack.addLast(drawStyle.copy())
    }

    fun popStyle() {
        drawStyle = styleStack.removeLast()
    }

    fun isolated(draw: CompositionDrawer.() -> Unit) {
        pushModel()
        pushStyle()
        draw()
        popModel()
        popStyle()
    }

    fun GroupNode.with(builder: CompositionDrawer.() -> Unit): GroupNode {
        val oldCursor = cursor
        cursor = this
        builder()
        cursor = oldCursor
        return this
    }

    /**
     * Create a group node and run `builder` inside its context
     * @param insert if true the created group will be inserted at [cursor]
     * @param id an optional identifier
     * @param builder the function that is executed inside the group context
     */
    fun group(insert: Boolean = true, id: String? = null, builder: CompositionDrawer.() -> Unit): GroupNode {
        val group = GroupNode()
        group.id = id
        val oldCursor = cursor

        if (insert) {
            cursor.children.add(group)
            group.parent = cursor
        }
        cursor = group
        builder()

        cursor = oldCursor
        return group
    }

    fun translate(x: Double, y: Double) = translate(Vector2(x, y))

    fun rotate(rotationInDegrees: Double) {
        model *= Matrix44.rotateZ(rotationInDegrees)
    }

    fun scale(s: Double) {
        model *= Matrix44.scale(s, s, s)
    }

    fun scale(x: Double, y: Double) {
        model *= Matrix44.scale(x, y, 1.0)
    }

    fun translate(t: Vector2) {
        model *= Matrix44.translate(t.vector3())
    }

    fun contour(contour: ShapeContour, insert: Boolean = true): ShapeNode? {
        if (contour.empty) {
            return null
        }
        val shape = Shape(listOf(contour))
        return shape(shape, insert)
    }

    fun contours(contours: List<ShapeContour>, insert: Boolean = true) = contours.map { contour(it, insert) }

    /**
     * Search for a point on a contour in the composition tree that's nearest to `point`
     * @param point the query point
     * @param searchFrom a node from which the search starts, defaults to composition root
     * @return an optional org.openrndr.shape.ShapeNodeNearestContour instance
     */
    fun nearest(
            point: Vector2,
            searchFrom: CompositionNode = composition.root as GroupNode
    ): ShapeNodeNearestContour? {
        return distances(point, searchFrom).firstOrNull()
    }

    fun CompositionNode.nearest(point: Vector2) = nearest(point, searchFrom = this)

    fun difference(
        shape: Shape,
        searchFrom: CompositionNode = composition.root as GroupNode
    ): Shape {
        val shapes = searchFrom.findShapes()
        var from = shape

        for (subtract in shapes) {
            if (shape.bounds.intersects(subtract.shape.bounds)) {
                from = difference(from, subtract.shape)
            }
        }
        return from
    }

    /**
     * Find distances to each contour in the composition tree (or starting node)
     * @param point the query point
     * @param searchFrom a node from which the search starts, defaults to composition root
     * @return a sorted list of [ShapeNodeNearestContour] describing distance to every contour
     */
    fun distances(
            point: Vector2,
            searchFrom: CompositionNode = composition.root as GroupNode
    ): List<ShapeNodeNearestContour> {
        return searchFrom.findShapes().flatMap { node ->
            node.shape.contours.filter { !it.empty }
                    .map { it.nearest(point) }
                    .map { ShapeNodeNearestContour(node, it, point - it.position, it.position.distanceTo(point)) }
        }.sortedBy { it.distance }
    }

    fun CompositionNode.distances(point: Vector2): List<ShapeNodeNearestContour> = distances(point, searchFrom = this)

    /**
     * Test a given `contour` against org.openrndr.shape.contours in the composition tree
     * @param contour the query contour
     * @param searchFrom a node from which the search starts, defaults to composition root
     * @param mergeThreshold minimum distance between intersections before they are merged together,
     * 0.0 or lower means no org.openrndr.shape.merge
     * @return a list of `org.openrndr.shape.ShapeNodeIntersection`
     */
    fun intersections(
        contour: ShapeContour,
        searchFrom: CompositionNode = composition.root as GroupNode,
        mergeThreshold: Double = 0.5
    ): List<ShapeNodeIntersection> {
        return searchFrom.findShapes().pflatMap { node ->
            if (node.bounds.intersects(contour.bounds)) {
                node.shape.contours.flatMap { nodeContour ->
                    intersections(contour, nodeContour).map {
                        ShapeNodeIntersection(node, it)
                    }
                }
            } else {
                emptyList()
            }
        }.let {
            if (mergeThreshold > 0.0) {
                it.merge(mergeThreshold)
            } else {
                it
            }
        }
    }

    fun CompositionNode.intersections(contour: ShapeContour, mergeThreshold: Double = 0.5) =
            intersections(contour, this, mergeThreshold)

    /**
     * Test a given `shape` against org.openrndr.shape.contours in the composition tree
     * @param shape the query shape
     * @param searchFrom a node from which the search starts, defaults to composition root
     * @return a list of `org.openrndr.shape.ShapeNodeIntersection`
     */
    fun intersections(
        shape: Shape,
        searchFrom: CompositionNode = composition.root as GroupNode,
        mergeThreshold: Double = 0.5
    ): List<ShapeNodeIntersection> {
        return shape.contours.flatMap {
            intersections(it, searchFrom, mergeThreshold)
        }
    }

    fun CompositionNode.intersections(shape: Shape, mergeThreshold: Double = 0.5) =
            intersections(shape, this, mergeThreshold)


    fun shape(shape: Shape, insert: Boolean = true): ShapeNode? {
        if (shape.empty) {
            return null
        }

        val inverseModel = model.inversed
        val postShape = mask?.let { intersection(shape, it.transform(inverseModel)) } ?: shape

        if (postShape.empty) {
            return null
        }

        // only use clipping for open shapes
        val clipMode = if (postShape.topology == ShapeTopology.CLOSED) clipMode else ClipMode.DISABLED

        return when (clipMode.op) {
            ClipOp.DISABLED, ClipOp.REVERSE_DIFFERENCE -> {
                val shapeNode = ShapeNode(postShape)

                val shapeTransform: Matrix44 = when (transformMode) {
                    TransformMode.KEEP -> {
                        shapeNode.transform = model
                        Matrix44.IDENTITY
                    }
                    TransformMode.APPLY -> {
                        shapeNode.transform = Matrix44.IDENTITY
                        model
                    }
                }
                shapeNode.shape = when (clipMode.op) {
                    ClipOp.DISABLED -> postShape.transform(shapeTransform)
                    ClipOp.REVERSE_DIFFERENCE -> {
                        val shapeNodes = (if (!clipMode.grouped) composition.findShapes() else cursor.findShapes())
                        var toInsert = shape
                        val inverse = model.inversed
                        for (node in shapeNodes) {
                            if (toInsert.empty) {
                                break
                            } else {
                                toInsert = difference(toInsert, node.effectiveShape.transform(inverse))
                            }
                        }
                        toInsert
                    }
                    else -> error("unreachable")
                }
                shapeNode.stroke = stroke
                shapeNode.strokeOpacity = strokeOpacity
                shapeNode.strokeWeight = strokeWeight
                shapeNode.miterLimit = miterlimit
                shapeNode.lineCap = lineCap
                shapeNode.lineJoin = lineJoin
                shapeNode.fill = fill
                shapeNode.fillOpacity = fillOpacity

                if (insert) {
                    cursor.children.add(shapeNode)
                    shapeNode.parent = cursor
                }
                shapeNode
            }
            else -> {
                val shapeNodes = (if (!clipMode.grouped) composition.findShapes() else cursor.findShapes())
                val toRemove = mutableListOf<CompositionNode>()
                shapeNodes.pforEach { shapeNode ->
                    val inverse = shapeNode.effectiveTransform.inversed
                    val transformedShape = postShape.transform(inverse * model)
                    val operated =
                            when (clipMode.op) {
                                ClipOp.INTERSECT -> intersection(shapeNode.shape, transformedShape)
                                ClipOp.UNION -> union(shapeNode.shape, transformedShape)
                                ClipOp.DIFFERENCE -> difference(shapeNode.shape, transformedShape)
                                else -> error("unsupported base op ${clipMode.op}")
                            }
                    if (!operated.empty) {
                        shapeNode.shape = operated
                    } else {
                        //synchronized(toRemove) {
                            toRemove.add(shapeNode)
                        //}
                    }
                }
                for (node in toRemove) {
                    node.remove()
                }
                null
            }
        }
    }

    fun shapes(shapes: List<Shape>, insert: Boolean = true) = shapes.map { shape(it, insert) }

    fun rectangle(rectangle: Rectangle, closed: Boolean = true, insert: Boolean = true) = contour(rectangle.contour.let {
        if (closed) {
            it
        } else {
            it.open
        }
    }, insert = insert)

    fun rectangle(x: Double, y: Double, width: Double, height: Double, closed: Boolean = true, insert: Boolean = true) = rectangle(
        Rectangle(x, y, width, height), closed, insert)

    fun rectangles(rectangles: List<Rectangle>, insert: Boolean = true) = rectangles.map { rectangle(it, insert) }

    fun rectangles(positions: List<Vector2>, width: Double, height: Double, insert: Boolean = true) = rectangles(positions.map {
        Rectangle(it, width, height)
    }, insert)

    fun rectangles(positions: List<Vector2>, dimensions: List<Vector2>, insert: Boolean) = rectangles((positions zip dimensions).map {
        Rectangle(it.first, it.second.x, it.second.y)
    }, insert)

    fun circle(x: Double, y: Double, radius: Double, closed: Boolean = true, insert: Boolean = true) = circle(
        Circle(
            Vector2(x, y),
            radius
        ), closed, insert)

    fun circle(position: Vector2, radius: Double, closed: Boolean = true, insert: Boolean = true) = circle(
        Circle(
            position,
            radius
        ), closed, insert)

    fun circle(circle: Circle, closed: Boolean = true, insert: Boolean = true) = contour(circle.contour.let {
        if (closed) {
            it
        } else {
            it.open
        }
    }, insert)

    fun circles(circles: List<Circle>, insert: Boolean = true) = circles.map { circle(it, insert) }

    fun circles(positions: List<Vector2>, radius: Double, insert: Boolean = true) = circles(positions.map {
        Circle(
            it,
            radius
        )
    }, insert)

    fun circles(positions: List<Vector2>, radii: List<Double>, insert: Boolean = true) = circles((positions zip radii).map {
        Circle(
            it.first,
            it.second
        )
    }, insert)

    /*
    fun ellipse(
            x: Double,
            y: Double,
            xRadius: Double,
            yRadius: Double,
            rotationInDegrees: Double = 0.0,
            closed: Boolean = true,
            insert: Boolean = true
    ) = ellipse(Vector2(x, y), xRadius, yRadius, rotationInDegrees, closed, insert)

    fun ellipse(
            center: Vector2,
            xRadius: Double,
            yRadius: Double,
            rotationInDegrees: Double,
            closed: Boolean = true,
            insert: Boolean = true
    ) = contour(OrientedEllipse(center, xRadius, yRadius, rotationInDegrees).contour.let {
        if (closed) {
            it
        } else {
            it.open
        }
    }, insert)
    */


    fun lineSegment(
            startX: Double,
            startY: Double,
            endX: Double,
            endY: Double,
            insert: Boolean = true
    ) = lineSegment(LineSegment(startX, startY, endX, endY), insert)

    fun lineSegment(
            start: Vector2,
            end: Vector2,
            insert: Boolean = true
    ) = lineSegment(LineSegment(start, end), insert)

    fun lineSegment(
        lineSegment: LineSegment,
        insert: Boolean = true
    ) = contour(lineSegment.contour, insert)

    fun lineSegments(
        lineSegments: List<LineSegment>,
        insert: Boolean = true
    ) = lineSegments.map {
        lineSegment(it, insert)
    }

    fun segment(
        start: Vector2,
        c0: Vector2,
        c1: Vector2,
        end: Vector2,
        insert: Boolean = true
    ) = segment(Segment(start, c0, c1, end), insert)

    fun segment(
        start: Vector2,
        c0: Vector2,
        end: Vector2,
        insert: Boolean = true
    ) = segment(Segment(start, c0, end), insert)

    fun segment(
        start: Vector2,
        end: Vector2,
        insert: Boolean = true
    ) = segment(Segment(start, end), insert)

    fun segment(
        segment: Segment,
        insert: Boolean = true
    ) = contour(segment.contour, insert)

    fun segments(
        segments: List<Segment>,
        insert: Boolean = true
    ) = segments.map {
        segment(it, insert)
    }

    fun lineStrip(
            points: List<Vector2>,
            insert: Boolean = true
    ) = contour(ShapeContour.fromPoints(points, false, YPolarity.CW_NEGATIVE_Y), insert)

    fun lineLoop(
            points: List<Vector2>,
            insert: Boolean = true
    ) = contour(ShapeContour.fromPoints(points, true, YPolarity.CW_NEGATIVE_Y), insert)

    fun text(
            text: String,
            position: Vector2,
            insert: Boolean = true
    ): TextNode {
        val g = GroupNode()
        g.style.transform = Transform.Matrix(transform { translate(position.xy0) })
        val textNode = TextNode(text, null).apply {
            this.style.fill = when (val f = this@CompositionDrawer.fill) {
                is ColorRGBa -> Paint.RGB(f)
                else -> Paint.None
            }

        }
        g.children.add(textNode)
        if (insert) {
            cursor.children.add(g)
        }
        return textNode
    }

    fun textOnContour(
        text: String,
        contour: ShapeContour,
        insert: Boolean = true
    ): TextNode {
        val textNode = TextNode(text, contour)
        if (insert) {
            cursor.children.add(textNode)
        }
        return textNode
    }

    fun texts(text: List<String>, positions: List<Vector2>) =
            (text zip positions).map {
                text(it.first, it.second)
            }

    /**
     * Adds an image to the composition tree
     */
    fun image(
            image: ColorBuffer,
            x: Double = 0.0,
            y: Double = 0.0,
            insert: Boolean = true
    ): ImageNode {
        val node = ImageNode(image, x, y, width = image.width.toDouble(), height = image.height.toDouble())
        node.style.transform = Transform.Matrix(this.model)
        if (insert) {
            cursor.children.add(node)
        }
        return node
    }

    fun composition(composition: Composition): CompositionNode {
        val rootContainer = GroupNode()
        val newRoot = composition.root.duplicate(insert = false)
        newRoot.parent = rootContainer
        rootContainer.children.add(newRoot)
        rootContainer.transform *= model
        rootContainer.parent = cursor
        cursor.children.add(rootContainer)

        return rootContainer
    }

    fun CompositionNode.translate(x: Double, y: Double, z: Double = 0.0) {
        transform = transform.transform {
            translate(x, y, z)
        }
    }

    fun CompositionNode.rotate(angleInDegrees: Double, pivot: Vector2 = Vector2.ZERO) {
        transform = transform.transform {
            translate(pivot.xy0)
            rotate(Vector3.UNIT_Z, angleInDegrees)
            translate(-pivot.xy0)
        }
    }

    fun CompositionNode.scale(scale: Double, pivot: Vector2 = Vector2.ZERO) {
        transform = transform.transform {
            translate(pivot.xy0)
            scale(scale, scale, scale)
            translate(-pivot.xy0)
        }
    }

    fun CompositionNode.transform(builder: TransformBuilder.() -> Unit) {
        return this.transform(builder)
    }

    /**
     * Returns a deep copy of a [CompositionNode].
     * If [insert] is true the copy is inserted at [cursor].
     * @return a deep copy of the node
     */
    // TODO: Include new features
    fun CompositionNode.duplicate(insert: Boolean = true): CompositionNode {
        fun nodeCopy(node: CompositionNode): CompositionNode {
            val copy = when (node) {
                is ImageNode -> {
                    ImageNode(node.image, node.x, node.y, node.width, node.height)
                }
                is ShapeNode -> {
                    ShapeNode(node.shape)
                }
                is TextNode -> {
                    TextNode(node.text, node.contour)
                }
                is GroupNode -> {
                    val children = node.children.map { nodeCopy(it) }.toMutableList()
                    val groupNode = GroupNode(children)
                    groupNode.children.forEach {
                        it.parent = groupNode
                    }
                    groupNode
                }
            }
            copy.style = node.style
            return copy
        }

        val copy = nodeCopy(this)
        if (insert) {
            this@CompositionDrawer.cursor.children.add(copy)
            copy.parent = cursor
        }
        return copy
    }
}

/**
 * Creates a [Composition]. The draw operations contained inside
 * the [drawFunction] do not render graphics to the screen,
 * but populate the Composition instead.
 */
fun drawComposition(
    documentBounds: CompositionDimensions = defaultCompositionDimensions,
    composition: Composition? = null,
    cursor: GroupNode? = composition?.root as? GroupNode,
    drawFunction: CompositionDrawer.() -> Unit
): Composition = CompositionDrawer(documentBounds, composition, cursor).apply { drawFunction() }.composition

/**
 * Draw into an existing [Composition].
 */
fun Composition.draw(drawFunction: CompositionDrawer.() -> Unit) {
    drawComposition(composition = this, drawFunction = drawFunction)
}