path: root/android-app/app/src/main/kotlin/org/terst/nav/PolarDiagramView.kt

package org.terst.nav

import android.content.Context
import android.graphics.Canvas
import android.graphics.Color
import android.graphics.Paint
import android.graphics.RectF
import android.util.AttributeSet
import android.view.View
import kotlin.math.cos
import kotlin.math.min
import kotlin.math.sin

class PolarDiagramView @JvmOverloads constructor(
    context: Context,
    attrs: AttributeSet? = null,
    defStyleAttr: Int = 0
) : View(context, attrs, defStyleAttr) {

    private val gridPaint = Paint().apply {
        color = Color.parseColor("#404040") // Dark gray for grid lines
        style = Paint.Style.STROKE
        strokeWidth = 1f
        isAntiAlias = true
    }

    private val textPaint = Paint().apply {
        color = Color.WHITE
        textSize = 24f
        isAntiAlias = true
        textAlign = Paint.Align.CENTER
    }

    private val polarCurvePaint = Paint().apply {
        color = Color.CYAN // Bright color for the polar curve
        style = Paint.Style.STROKE
        strokeWidth = 3f
        isAntiAlias = true
    }

    private val currentPerformancePaint = Paint().apply {
        color = Color.RED // Red dot for current performance
        style = Paint.Style.FILL
        isAntiAlias = true
    }

    private val noSailZonePaint = Paint().apply {
        color = Color.parseColor("#80FF0000") // Semi-transparent red for no-sail zone
        style = Paint.Style.FILL
        isAntiAlias = true
    }

    private val optimalVmgPaint = Paint().apply {
        color = Color.GREEN // Green for optimal VMG angles
        style = Paint.Style.STROKE
        strokeWidth = 4f
        isAntiAlias = true
    }

    private var viewCenterX: Float = 0f
    private var viewCenterY: Float = 0f
    private var radius: Float = 0f

    // Data for rendering
    private var polarTable: PolarTable? = null
    private var currentTws: Double = 0.0
    private var currentTwa: Double = 0.0
    private var currentBsp: Double = 0.0

    // Configuration for the diagram
    private val maxSpeedKnots = 10.0 // Max speed for the outermost circle in knots
    private val speedCircleInterval = 2.0 // Interval between speed circles in knots
    private val twaInterval = 30 // Interval between TWA radial lines in degrees
    private val noSailZoneAngle = 20.0 // Angle +/- from 0 degrees for no-sail zone

    override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {
        super.onSizeChanged(w, h, oldw, oldh)
        viewCenterX = w / 2f
        viewCenterY = h / 2f
        radius = min(w, h) / 2f * 0.9f // Use 90% of the minimum dimension for radius
    }

    override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)

        // Draw basic diagram elements
        drawGrid(canvas)
        drawTwaLabels(canvas)
        drawNoSailZone(canvas)

        // Draw polar curve if data is available
        polarTable?.let {
            drawPolarCurve(canvas, it, currentTws)
            drawOptimalVmgAngles(canvas, it, currentTws) // Draw optimal VMG angles
        }

        // Draw current performance if data is available and not zero
        if (currentTws > 0 && currentTwa > 0 && currentBsp > 0) {
            drawCurrentPerformance(canvas, currentTwa, currentBsp)
        }
    }

    private fun drawGrid(canvas: Canvas) {
        // Draw TWA radial lines (0 to 360 degrees)
        for (i in 0 until 360 step twaInterval) {
            val angleRad = Math.toRadians(i.toDouble())
            val x = viewCenterX + radius * cos(angleRad).toFloat()
            val y = viewCenterY + radius * sin(angleRad).toFloat()
            canvas.drawLine(viewCenterX, viewCenterY, x, y, gridPaint)
        }

        // Draw speed circles
        for (i in 0..maxSpeedKnots.toInt() step speedCircleInterval.toInt()) {
            val currentRadius = (i / maxSpeedKnots * radius).toFloat()
            canvas.drawCircle(viewCenterX, viewCenterY, currentRadius, gridPaint)
        }
    }

    private fun drawTwaLabels(canvas: Canvas) {
        // Draw TWA labels around the perimeter
        for (i in 0 until 360 step twaInterval) {
            val displayAngleRad = Math.toRadians(i.toDouble())
            // Position the text slightly outside the outermost circle
            val textX = viewCenterX + (radius + 40) * cos(displayAngleRad).toFloat()
            // Adjust textY to account for text height, so it's centered vertically on the arc
            val textY = viewCenterY + (radius + 40) * sin(displayAngleRad).toFloat() + (textPaint.textSize / 3)

            // Map canvas angle (0=right, 90=down) to polar diagram angle (0=up, 90=right)
            // Example: canvas 270 is polar 0, canvas 0 is polar 90, canvas 90 is polar 180, canvas 180 is polar 270
            val polarAngle = ( (i + 90) % 360 )
            canvas.drawText(polarAngle.toString(), textX, textY, textPaint)
        }

        // Draw speed labels on the horizontal axis
        for (i in 0..maxSpeedKnots.toInt() step speedCircleInterval.toInt()) {
            if (i > 0) {
                val currentRadius = (i / maxSpeedKnots * radius).toFloat()
                // Left side
                canvas.drawText(i.toString(), viewCenterX - currentRadius - 10, viewCenterY + (textPaint.textSize / 3), textPaint)
                // Right side
                canvas.drawText(i.toString(), viewCenterX + currentRadius + 10, viewCenterY + (textPaint.textSize / 3), textPaint)
            }
        }
    }

    private fun drawNoSailZone(canvas: Canvas) {
        // The no-sail zone is typically symmetric around the wind direction (0 TWA, which is 'up' on our diagram)
        // In canvas coordinates, 'up' is -90 degrees or 270 degrees.
        // So the arc will be centered around 270 degrees.
        val startAngle = (270 - noSailZoneAngle).toFloat()
        val sweepAngle = (2 * noSailZoneAngle).toFloat()

        val oval = RectF(viewCenterX - radius, viewCenterY - radius, viewCenterX + radius, viewCenterY + radius)
        canvas.drawArc(oval, startAngle, sweepAngle, true, noSailZonePaint)
    }

    private fun drawPolarCurve(canvas: Canvas, polarTable: PolarTable, tws: Double) {
        val path = android.graphics.Path()
        var firstPoint = true

        // Generate points for 0 to 180 TWA (starboard side)
        for (twa in 0..180) {
            val bsp = polarTable.interpolateBsp(tws, twa.toDouble())
            if (bsp > 0) {
                // Map TWA to canvas angle for the starboard side (0 TWA at 270, 90 TWA at 0, 180 TWA at 90)
                val canvasAngle = (270 + twa).toDouble() % 360
                val currentRadius = (bsp / maxSpeedKnots * radius).toFloat()
                val x = viewCenterX + currentRadius * cos(Math.toRadians(canvasAngle)).toFloat()
                val y = viewCenterY + currentRadius * sin(Math.toRadians(canvasAngle)).toFloat()

                if (firstPoint) {
                    path.moveTo(x, y)
                    firstPoint = false
                } else {
                    path.lineTo(x, y)
                }
            }
        }

        // Generate points for 0 to -180 TWA (port side) by mirroring
        // Start from 180 back to 0 to connect the curve
        for (twa in 180 downTo 0) {
            val bsp = polarTable.interpolateBsp(tws, twa.toDouble())
            if (bsp > 0) {
                // Map negative TWA to canvas angle for the port side (0 TWA at 270, -90 TWA at 180, -180 TWA at 90)
                val canvasAngle = (270 - twa).toDouble() // This maps TWA 0 to 270, TWA 90 to 180, TWA 180 to 90
                val currentRadius = (bsp / maxSpeedKnots * radius).toFloat()
                val x = viewCenterX + currentRadius * cos(Math.toRadians(canvasAngle)).toFloat()
                val y = viewCenterY + currentRadius * sin(Math.toRadians(canvasAngle)).toFloat()

                path.lineTo(x, y) // Continue drawing the path
            }
        }
        canvas.drawPath(path, polarCurvePaint)
    }

    private fun drawCurrentPerformance(canvas: Canvas, twa: Double, bsp: Double) {
        val canvasAngle = if (twa >= 0) {
            (270 + twa).toDouble() % 360 // Starboard side
        } else {
            (270 + twa).toDouble() // Port side (e.g., -30 TWA is 240 canvas angle)
        }

        val currentRadius = (bsp / maxSpeedKnots * radius).toFloat()
        val x = viewCenterX + currentRadius * cos(Math.toRadians(canvasAngle)).toFloat()
        val y = viewCenterY + currentRadius * sin(Math.toRadians(canvasAngle)).toFloat()

        canvas.drawCircle(x, y, 10f, currentPerformancePaint) // Draw a small circle for current performance
    }

    private fun drawOptimalVmgAngles(canvas: Canvas, polarTable: PolarTable, tws: Double) {
        // Find optimal upwind TWA
        val optimalUpwindTwa = polarTable.findOptimalUpwindTwa(tws)
        if (optimalUpwindTwa > 0) {
            // Draw a line indicating the optimal upwind TWA (both port and starboard)
            val upwindBsp = polarTable.interpolateBsp(tws, optimalUpwindTwa)
            val currentRadius = (upwindBsp / maxSpeedKnots * radius).toFloat() * 1.05f // Slightly longer

            // Starboard side
            var canvasAngle = (270 + optimalUpwindTwa).toDouble() % 360
            var x = viewCenterX + currentRadius * cos(Math.toRadians(canvasAngle)).toFloat()
            var y = viewCenterY + currentRadius * sin(Math.toRadians(canvasAngle)).toFloat()
            canvas.drawLine(viewCenterX, viewCenterY, x, y, optimalVmgPaint)

            // Port side
            canvasAngle = (270 - optimalUpwindTwa).toDouble() // Use negative TWA for port side
            x = viewCenterX + currentRadius * cos(Math.toRadians(canvasAngle)).toFloat()
            y = viewCenterY + currentRadius * sin(Math.toRadians(canvasAngle)).toFloat()
            canvas.drawLine(viewCenterX, viewCenterY, x, y, optimalVmgPaint)
        }

        // Find optimal downwind TWA
        val optimalDownwindTwa = polarTable.findOptimalDownwindTwa(tws)
        if (optimalDownwindTwa > 0) {
            // Draw a line indicating the optimal downwind TWA (both port and starboard)
            val downwindBsp = polarTable.interpolateBsp(tws, optimalDownwindTwa)
            val currentRadius = (downwindBsp / maxSpeedKnots * radius).toFloat() * 1.05f // Slightly longer

            // Starboard side
            var canvasAngle = (270 + optimalDownwindTwa).toDouble() % 360
            var x = viewCenterX + currentRadius * cos(Math.toRadians(canvasAngle)).toFloat()
            var y = viewCenterY + currentRadius * sin(Math.toRadians(canvasAngle)).toFloat()
            canvas.drawLine(viewCenterX, viewCenterY, x, y, optimalVmgPaint)

            // Port side
            canvasAngle = (270 - optimalDownwindTwa).toDouble() // Use negative TWA for port side
            x = viewCenterX + currentRadius * cos(Math.toRadians(canvasAngle)).toFloat()
            y = viewCenterY + currentRadius * sin(Math.toRadians(canvasAngle)).toFloat()
            canvas.drawLine(viewCenterX, viewCenterY, x, y, optimalVmgPaint)
        }
    }

    /**
     * Sets the polar table data for the view.
     */
    fun setPolarTable(table: PolarTable) {
        this.polarTable = table
        invalidate() // Redraw the view
    }

    /**
     * Sets the current true wind speed, true wind angle, and boat speed.
     */
    fun setCurrentPerformance(tws: Double, twa: Double, bsp: Double) {
        this.currentTws = tws
        this.currentTwa = twa
        this.currentBsp = bsp
        invalidate() // Redraw the view
    }
}