// Author:  cirakg & claude ai
// Summary: Barcode symbology IDs, option bits, result types and the dispatcher to the encoders (README 12).
//
// A code entry stores its symbology in Entry.type and its options in
// Entry.options (bits below). encode() turns the payload text into either a
// LinearCode (one row of modules) or, from M6b, a matrix; validation errors
// come back as a CodeError with a message for the user, never an exception.

import Toybox.Lang;

module Codes {

    // Symbology IDs (Entry.type of code entries). Stored: never renumber.
    const QR = 0;
    const CODE128 = 1;
    const CODE39 = 2;
    const EAN13 = 3;
    const EAN8 = 4;
    const UPCA = 5;
    const UPCE = 6;
    const ITF = 7;
    const CODABAR = 8;
    const DATAMATRIX = 9;
    const PDF417 = 10;
    const AZTEC = 11;

    const NAMES = ["QR", "Code 128", "Code 39", "EAN-13", "EAN-8", "UPC-A", "UPC-E", "ITF", "Codabar", "Data Matrix",
        "PDF417", "Aztec"];

    // Entry.options bits.
    const OPT_EC_MASK = 0x3;         // error correction: 0 low, 1 medium, 2 quartile, 3 high
    const OPT_CHECK_SHIFT = 2;       // check digit: 0 add or verify, 1 fix if wrong, 2 off
    const OPT_CHECK_MASK = 0xC;
    const OPT_SHOW_TEXT = 0x10;      // human-readable text under linear codes
    const DEFAULT_OPTIONS = 0x11;    // medium, add or verify, text on

    const CHECK_ADD_VERIFY = 0;
    const CHECK_FIX = 1;
    const CHECK_OFF = 2;

    // A row of modules: modules[i] is 1 for a bar, 0 for a space. The quiet
    // zone is not included (the renderer adds it).
    class LinearCode {
        var modules as ByteArray;
        // The human-readable text (digits as encoded, check digit included).
        var text as String;
        // A remark for the user (check digit added or fixed), or null.
        var note as String? = null;

        function initialize(rowModules as ByteArray, readable as String) {
            modules = rowModules;
            text = readable;
        }
    }

    // Why a payload can't be encoded, in words for the user.
    class CodeError {
        var message as String;

        function initialize(msg as String) {
            message = msg;
        }
    }

    function checkMode(options as Number) as Number {
        return (options & OPT_CHECK_MASK) >> OPT_CHECK_SHIFT;
    }

    function name(symbology as Number) as String {
        return symbology >= 0 && symbology < NAMES.size() ? NAMES[symbology] as String : "Code";
    }

    function isLinear(symbology as Number) as Boolean {
        return symbology >= CODE128 && symbology <= CODABAR;
    }

    // Encode a payload; unsupported symbologies give a CodeError until
    // their milestone (README 16, M6b-M6d).
    function encode(symbology as Number, payload as String, options as Number) as LinearCode or CodeError {
        var check = checkMode(options);
        if (symbology == EAN13) {
            return Ean.ean13(payload, check, "EAN-13", false);
        }
        if (symbology == UPCA) {
            return Ean.ean13(payload, check, "UPC-A", true);
        }
        if (symbology == EAN8) {
            return Ean.ean8(payload, check);
        }
        if (symbology == UPCE) {
            return Ean.upce(payload, check);
        }
        if (symbology == CODE128) {
            return Code128.encode(payload);
        }
        if (symbology == CODE39) {
            return Code39.encode(payload, check != CHECK_OFF);
        }
        if (symbology == ITF) {
            return Itf.encode(payload, check != CHECK_OFF);
        }
        if (symbology == CODABAR) {
            return Codabar.encode(payload);
        }
        return new CodeError(name(symbology) + " is not supported yet");
    }

    // Append bar/space runs to modules: widths alternate bar, space, ...,
    // starting with a bar when startWithBar.
    function addRuns(modules as ByteArray, widths as Array<Number>, startWithBar as Boolean) as Void {
        var bar = startWithBar;
        for (var i = 0; i < widths.size(); i++) {
            var w = widths[i];
            for (var k = 0; k < w; k++) {
                modules.add(bar ? 1 : 0);
            }
            bar = !bar;
        }
    }

    // Append a bit pattern of `count` modules, most significant bit first.
    function addBits(modules as ByteArray, bits as Number, count as Number) as Void {
        for (var i = count - 1; i >= 0; i--) {
            modules.add((bits >> i) & 1);
        }
    }

    // The digit values of text, or null when it holds anything else.
    function digits(text as String) as Array<Number>? {
        var chars = text.toCharArray();
        var out = [] as Array<Number>;
        for (var i = 0; i < chars.size(); i++) {
            var c = chars[i];
            if (c < '0' || c > '9') {
                return null;
            }
            out.add(c.toNumber() - 48);
        }
        return out;
    }

    function digitsText(values as Array<Number>) as String {
        var s = "";
        for (var i = 0; i < values.size(); i++) {
            s += values[i].toString();
        }
        return s;
    }
}