package com.peachpasswords.codex

import android.graphics.Bitmap
import com.google.zxing.BinaryBitmap
import com.google.zxing.DecodeHintType
import com.google.zxing.LuminanceSource
import com.google.zxing.RGBLuminanceSource
import com.google.zxing.aztec.AztecReader
import com.google.zxing.aztec.encoder.Encoder
import com.google.zxing.common.BitMatrix
import com.google.zxing.common.GlobalHistogramBinarizer
import com.google.zxing.common.HybridBinarizer

/** Aztec encode/decode for one Codex chunk, via ZXing. */
object CodexAztec {

    /**
     * The native, unscaled per-module bit matrix (no ZXing quiet-zone padding
     * or upscaling) — for drawing the code as PDF vector rectangles rather
     * than an embedded raster image. See [CodexPdf] for why: PdfDocument's
     * raster image embedding was found to corrupt crisp module boundaries
     * (confirmed via a direct in-memory encode-then-decode round trip, which
     * succeeds 100% of the time, vs. decoding the same code back out of a
     * generated-then-rendered PDF, which failed almost entirely). Same ECC
     * percent and (absent) charset/layers hints ZXing's AztecWriter would use
     * by default — this is byte-for-byte the same code, just the raw module
     * grid instead of a padded/scaled bitmap.
     */
    fun encodeMatrix(content: String): BitMatrix =
        Encoder.encode(content, AZTEC_ECC_PERCENT, 0, null).matrix

    /**
     * Decode an Aztec code from a tightly-cropped [Bitmap]. A rendered,
     * cropped single code decodes most reliably with PURE_BARCODE (skip the
     * locate-in-scene search); fall back to the full detector for codes that
     * carry surrounding bleed. Null if neither reads.
     */
    fun decode(bitmap: Bitmap): String? {
        val w = bitmap.width
        val h = bitmap.height
        val pixels = IntArray(w * h)
        bitmap.getPixels(pixels, 0, w, 0, 0, w, h)
        val source: LuminanceSource = RGBLuminanceSource(w, h, pixels)
        val pure = mapOf(DecodeHintType.PURE_BARCODE to true, DecodeHintType.TRY_HARDER to true)
        val scene = mapOf(DecodeHintType.TRY_HARDER to true)
        // Cross both binarizers (Hybrid is adaptive; Global handles flat,
        // evenly-lit renders) with both detector modes — marginal codes that
        // miss one combination usually read on another.
        val attempts = listOf(
            BinaryBitmap(HybridBinarizer(source)) to pure,
            BinaryBitmap(HybridBinarizer(source)) to scene,
            BinaryBitmap(GlobalHistogramBinarizer(source)) to pure,
        )
        for ((binarizer, hints) in attempts) {
            try {
                return AztecReader().decode(binarizer, hints).text
            } catch (_: Exception) {
                // try next strategy
            }
        }
        return null
    }
}