import { Angle, Color } from '../../numbers'
import { AgentSet, CellGrid } from '../../structures'
import { Agent, Cell } from '../../entities'
import { AgentStyle } from '../../entities/Agent'

export interface Render2DConstructor {
    root: HTMLElement
    renderWidth: number
    renderHeight: number
    worldWidth: number
    id?: string
    title?: string
    autoPlay?: boolean
    frameRate?: number
    onCellClick?: (position: [number, number], renderer: Render2D) => void
}

export type ColorFunction<U extends Agent|Cell> = (entity: U) => {
    fill: Color,
    stroke?: Color
}

export type StyleFunction<T extends Agent> = (entity: T) => AgentStyle

export class Render2D {
    renderWidth: number // in pixels
    renderHeight: number // in pixels
    ctx: CanvasRenderingContext2D
    frameRate: number

    cellWidth: number
    cellHeight: number

    constructor(opts: Render2DConstructor) {

        const {
            root,
            worldWidth,
            renderHeight,
            renderWidth,
            title,
            id,
            autoPlay,
            frameRate
        } = opts

        // create a draggable canvas element
        const draggable = document.createElement('drag-pane')

        draggable.style.zIndex = '1'
        draggable.id = 'canvas_main'
        draggable.setAttribute('heading', title )
        draggable.setAttribute('key', id)

        this.renderHeight = renderHeight
        this.renderWidth = renderWidth
        this.cellWidth = renderWidth / worldWidth
        this.cellHeight = renderHeight / worldWidth

        const canvas = document.createElement('canvas')
        this.ctx = canvas.getContext('2d')!
        canvas.width = renderWidth
        canvas.height = renderHeight

        // create a click event handler for the canvas
        canvas.addEventListener('click', (e) => {
            const rect = canvas.getBoundingClientRect()
            const x = e.clientX - rect.left
            const y = e.clientY - rect.top

            // dispatch a custom event with the clicked cell coordinates
            const event = new CustomEvent('inspectClick', {
                detail: [Math.floor(x / this.cellWidth),Math.floor(y / this.cellHeight)]
            })

            if (opts.onCellClick) {
                opts.onCellClick([Math.floor(x / this.cellWidth), Math.floor(y / this.cellHeight)], this)
            }

            window.dispatchEvent(event)
        })

        draggable.appendChild(canvas)


        const controlBar = document.createElement('animation-toolbar')
        controlBar.setAttribute('autoPlay', autoPlay.toString())
        controlBar.setAttribute('fps', frameRate.toString())
        draggable.appendChild(controlBar)

        root.appendChild(draggable)

    }


    clear() {
        this.ctx.clearRect(0, 0, this.renderWidth, this.renderHeight)
    }

    drawCellGrid<T extends Cell>(world: CellGrid<T>,
        opts:{
            colorFunction?: ColorFunction<T>
        } = {}
    ) {
        const { colorFunction } = opts

        for (let x = 0; x < world.width; x++) {
            for (let y = 0; y < world.height; y++) {
                const cell = world.getCell([x, y])

                const color = colorFunction
                    ? colorFunction(cell)
                    : {
                        fill: cell.color,
                        stroke: cell.strokeColor
                    }


                this.drawRectangle(
                    x,
                    y,
                    {
                        width: this.cellWidth,
                        height: this.cellHeight,
                        fill: color.fill,
                        stroke: color.stroke
                    }
                )
            }
        }
    }


    /**
     * Draws agents on the canvas
     * @param agents
     */
    drawAgentSet<T extends Agent>(
        agents: AgentSet<T>,
        opts: {
            colorFunction?: ColorFunction<T>,
            styleFunction?: StyleFunction<T>
        } = {}
    ) {
        const { colorFunction, styleFunction } = opts
        agents.forEach(agent => {
            this.drawAgent(agent, { colorFunction, styleFunction })
        })
    }

    drawAgent<T extends Agent>(
        agent: T,
        opts: {
            colorFunction?: ColorFunction<T>,
            styleFunction?: StyleFunction<T>
        } = {}
    ) {
        const { colorFunction, styleFunction } = opts

        const color = colorFunction
            ? colorFunction(agent)
            : {
                fill: agent.color,
                stroke: agent.strokeColor
            }

        const style = styleFunction
            ? styleFunction(agent)
            : agent.style

        const [x, y] = agent.position.components

        const options = {
            width: agent.radius,
            height: agent.radius,
            radius: agent.radius,
            rotation: agent.rotation,
            fill: color.fill,
            stroke: color.stroke
        }

        if (style === AgentStyle.CIRCLE) {
            this.drawCircle(
                x,
                y,
                options
            )
        }

        if (style === AgentStyle.TRIANGLE) {
            this.drawTriangle(
                x,
                y,
                options
            )
        }

        if (style === AgentStyle.SQUARE) {
            this.drawRectangle(
                x,
                y,
                options
            )
        }
    }

    public drawCircle(
        x: number,
        y: number,
        options?: {
            radius?: number,
            rotation?: Angle,
            fill?: Color,
            stroke?: Color
            lineWidth?: number
            showRotation?: boolean
        }
    ) {
        const {
            radius = 1,
            rotation = new Angle(0, 'rad'),
            fill = Color.fromName('blue'),
            stroke = undefined,
            showRotation = true,
            lineWidth = 1
        } = options ?? {}

        const _x = x * this.cellWidth
        const _y = y * this.cellHeight
        const _radius = radius * (this.cellWidth / 2)

        this.ctx.fillStyle = fill.toRGB()
        this.ctx.beginPath()
        this.ctx.arc(_x, _y, _radius, 0, 2 * Math.PI)
        this.ctx.fill()
        if (stroke) {
            this.ctx.strokeStyle = stroke.toRGB()
            this.ctx.stroke()
        }

        // draw a line from the center of the circle to the edge to show rotation
        if (rotation && showRotation) {
            this.ctx.beginPath()
            this.ctx.moveTo(_x, _y)
            this.ctx.lineTo(_x + _radius * Math.cos(rotation.asRadians()), _y + _radius * Math.sin(rotation.asRadians()))

        }
        if (stroke) {
            this.ctx.strokeStyle = stroke.toRGB()
            this.ctx.lineWidth = lineWidth
            this.ctx.stroke()
        }
    }

    /**
     * Draws a unit rectangle centered at x,y
     */
    public drawRectangle(
        x: number,
        y: number,
        options?: {
            width?: number,
            height?: number,
            rotation?: Angle,
            fill?: Color,
            stroke?: Color
            lineWidth?: number
        }
    ) {
        const {
            width = 1,
            height = 1,
            rotation = new Angle(0, 'rad'),
            fill = Color.fromName('blue'),
            stroke = undefined,
            lineWidth = 1
        } = options ?? {}

        const _x = x * this.cellWidth
        const _y = y * this.cellHeight
        const _width = width * this.cellWidth
        const _height = height * this.cellHeight


        this.ctx.fillStyle = fill.toRGB()
        this.ctx.fillRect(_x, _y, _width, _height)
        if (stroke) {
            this.ctx.strokeStyle = stroke.toRGB()
            this.ctx.strokeRect(_x, _y, _width, _height)
        }

        // draw a line from the center of the rectangle to the edge to show rotation
        if (rotation) {
            this.ctx.beginPath()
            this.ctx.moveTo(_x + _width / 2, _y + _height / 2)
            this.ctx.lineTo(_x + _width / 2 + _width / 2 * Math.cos(rotation.asRadians()), _y + _height / 2 + _height / 2 * Math.sin(rotation.asRadians()))

            if (stroke) {
                this.ctx.strokeStyle = stroke.toRGB()
                this.ctx.lineWidth = lineWidth
                this.ctx.stroke()
            }
        }
    }

    public drawLine(
        x1: number,
        y1: number,
        x2: number,
        y2: number,
        stroke: Color,
        options?: {
            lineWidth?: number
        }
    ) {
        this.ctx.beginPath()
        this.ctx.moveTo(x1 * this.cellWidth, y1 * this.cellHeight)
        this.ctx.lineTo(x2 * this.cellWidth, y2 * this.cellHeight)
        this.ctx.strokeStyle = stroke.toRGB()
        this.ctx.lineWidth = options?.lineWidth ?? 1
        this.ctx.stroke()
    }


    public drawTriangle(
        x: number,
        y: number,
        options?: {
            width?: number,
            rotation?: Angle,
            fill?: Color
            stroke?: Color,
            lineWidth?: number
        }
    ) {

        const {
            width = 1,
            rotation = new Angle(0, 'rad'),
            fill = Color.fromName('blue'),
            stroke = undefined,
        } = options

        const _width = width * this.cellWidth
        const _x = x * this.cellWidth
        const _y = y * this.cellHeight


        // Define the triangle's vertices relative to the origin
        const halfWidth = _width / 2
        const height = (Math.sqrt(3) / 2) * _width + _width / 2 // Height of an equilateral triangle

        const vertices = [
            { x: 0, y: -height / 2 }, // Top vertex
            { x: -halfWidth, y: height / 2 }, // Bottom-left vertex
            { x: halfWidth, y: height / 2 } // Bottom-right vertex
        ]

        // Save the current state of the canvas
        this.ctx.save()

        // Translate to the origin
        this.ctx.translate(_x, _y)

        // Rotate by R radians
        this.ctx.rotate(rotation.asDegrees())

        // Begin drawing the triangle
        this.ctx.beginPath()

        this.ctx.moveTo(vertices[0].x, vertices[0].y) // Move to the first vertex
        for (let i = 1; i < vertices.length; i++) {
            this.ctx.lineTo(vertices[i].x, vertices[i].y)
        }

        this.ctx.closePath()

        // Fill and stroke the triangle
        this.ctx.fillStyle = fill.toRGB()
        this.ctx.fill()
        this.ctx.strokeStyle = stroke.toRGB()
        this.ctx.lineWidth = options?.lineWidth ?? 1
        this.ctx.stroke()

        // Restore the canvas to its original state
        this.ctx.restore()
    }


    public drawPolygon(
        points: [number, number][],
        options?: {
            fill?: Color
            stroke?: Color,
            lineWidth?: number
        }
    ): void {
        const {
            fill = Color.fromName('blue'),
            stroke = undefined
        } = options ?? {}

        if (points.length < 3) {
            throw new Error('A polygon must have at least 3 vertices')
        }

        // Begin the path
        this.ctx.beginPath()

        // Move to the first point
        const firstPoint = points[0]
        const x0 = firstPoint[0] * this.cellWidth
        const y0 = firstPoint[1] * this.cellHeight
        this.ctx.moveTo(x0, y0)

        // Draw lines to the remaining points
        for (let i = 1; i < points.length; i++) {
            const point = points[i]
            const x = point[0] * this.cellWidth
            const y = point[1] * this.cellHeight
            this.ctx.lineTo(x, y)
        }

        // Close the path
        this.ctx.closePath()

        // Fill the polygon
        if (fill) {
            this.ctx.fillStyle = fill.toRGB()
            this.ctx.fill()
        }

        // Stroke the polygon
        if (stroke) {
            this.ctx.strokeStyle = stroke.toRGB()
            this.ctx.lineWidth = options?.lineWidth ?? 1
            this.ctx.stroke()
        }

        // Restore the context
        this.ctx.restore()
    }

    public drawPolyline(
        points: [number, number][],
        stroke: Color,
        options?: {
            lineWidth?: number
        }
    ): void {
        if (points.length < 2) {
            throw new Error('A polyline must have at least 2 vertices')
        }

        // Begin the path
        this.ctx.beginPath()

        // Move to the first point
        const firstPoint = points[0]
        const x0 = firstPoint[0] * this.cellWidth
        const y0 = firstPoint[1] * this.cellHeight
        this.ctx.moveTo(x0, y0)

        // Draw lines to the remaining points
        for (let i = 1; i < points.length; i++) {
            const point = points[i]
            const x = point[0] * this.cellWidth
            const y = point[1] * this.cellHeight
            this.ctx.lineTo(x, y)
        }

        // Stroke the polyline
        this.ctx.lineWidth = options?.lineWidth ?? 1
        this.ctx.strokeStyle = stroke.toRGB()
        this.ctx.stroke()

        // Restore the context
        this.ctx.restore()
    }


}

export default Render2D