package io.flamenet.e2e

import java.awt.image.BufferedImage
import java.io.File
import javax.imageio.ImageIO
import kotlin.test.Test

/**
 * Renders QR codes to PNG so an INDEPENDENT decoder can read them back.
 */
class QrCodeRenderForDecodingTest {
    @Test
    fun `render the corpus`() {
        val out = File(System.getProperty("fnmsg.qr.out") ?: "build/qr-corpus")
        out.mkdirs()
        CORPUS.forEachIndexed { index, text ->
            ImageIO.write(render(text, scale = 8, quiet = 4), "png", File(out, "qr-$index.png"))
            File(out, "qr-$index.txt").writeText(text)
        }
        println("wrote ${CORPUS.size} QR images to ${out.absolutePath}")
    }

    private fun render(
        text: String,
        scale: Int,
        quiet: Int,
    ): BufferedImage {
        val m = QrCode.encode(text)
        val side = (m.size + quiet * 2) * scale
        val image = BufferedImage(side, side, BufferedImage.TYPE_INT_RGB)
        val g = image.createGraphics()
        g.color = java.awt.Color.WHITE
        g.fillRect(0, 0, side, side)
        g.color = java.awt.Color.BLACK
        for (r in 0 until m.size) {
            for (c in 0 until m.size) {
                if (m[r, c]) g.fillRect((c + quiet) * scale, (r + quiet) * scale, scale, scale)
            }
        }
        g.dispose()
        return image
    }

    companion object {
        /**
         * Chosen to cross every version boundary the encoder supports, because
         * the block layout, the alignment patterns and the version-information
         * block all change with version and each is its own chance to be wrong.
         */
        val CORPUS: List<String> =
            listOf(
                "flamenet:fnid:kx7q2m", // v1
                "flamenet:fnid:" + "a".repeat(52) + "@relay1.flamenet.io", // a real address
                "flamenet:fnid:" + "b".repeat(52) + "@" + "long".repeat(8) + ".example.com",
                // Exactly full, version by version: data codewords minus the mode
                // nibble and character count.
                "x".repeat(14), // v1
                "x".repeat(26), // v2
                "x".repeat(42), // v3
                "x".repeat(62), // v4
                "x".repeat(84), // v5
                "x".repeat(106), // v6
                "x".repeat(122), // v7, first version with a version-information block
                "x".repeat(152), // v8, two block groups of different sizes
                "x".repeat(180), // v9
                "x".repeat(213), // v10, the largest this encoder makes
            )
    }
}