function dspInput = loadDspInputFromFilePaths(run_id, options)
%LOADDSPINPUTFROMFILEPATHS Load explicit signal files and prepare DSP input.

arguments
    run_id
    options struct
end

Tx_bits = load(textScalar(options.load_file_path.tx_bits_path));
Symbols = load(textScalar(options.load_file_path.tx_symbols_path));
Scpe_sig_raw = load(textScalar(options.load_file_path.rx_raw_path));

Tx_bits = Tx_bits.Bits;
Symbols = Symbols.Symbols;
Scpe_sig_raw = Scpe_sig_raw.Scpe_sig_raw;

fsym = Symbols.fs;
M = Symbols.logbook.ModifierCopy{1}.M;
duob_mode = Symbols.logbook.ModifierCopy{1}.duobinary_mode;

Scpe_sig_resampled = Scpe_sig_raw.resample("fs_in", Scpe_sig_raw.fs, "fs_out", 2*fsym);
[~, Scpe_cell, ~, found_sync] = Scpe_sig_resampled.tsynch("reference", Symbols, ...
    "fs_ref", fsym, ...
    "debug_plots", 1);

if found_sync
    Scpe_cell = selectSyncedOccurrences(Scpe_cell, options);
else
    warning('Could not synchronize the received signal with the stored symbols!');
end

dspInput = struct();
dspInput.run_id = run_id;
dspInput.dataTable = table();
dspInput.Tx_bits = Tx_bits;
dspInput.Symbols = Symbols;
dspInput.Scpe_cell = Scpe_cell;
dspInput.found_sync = found_sync;
dspInput.fsym = fsym;
dspInput.M = M;
dspInput.duob_mode = duob_mode;
end

function value = textScalar(value)
value = firstValue(value);
value = char(string(value));
end

function value = firstValue(value)
if iscell(value)
    value = value{1};
elseif ~ischar(value) && ~isscalar(value)
    value = value(1);
end
end

function Scpe_cell = selectSyncedOccurrences(Scpe_cell, options)
available_occurences = length(Scpe_cell);
start_occurence = floor(getOption(options, 'start_occurence', 1));
max_occurences = floor(getOption(options, 'max_occurences', available_occurences));

if available_occurences < 1
    warning('loadDspInputFromFilePaths:NoSyncedOccurrences', ...
        'Synchronization reported success, but no synced occurrences are available.');
    return
end

if start_occurence < 1
    error('loadDspInputFromFilePaths:InvalidStartOccurrence', ...
        'start_occurence must be >= 1.');
end

if max_occurences < 1
    Scpe_cell = Scpe_cell(1:0);
    return
end

if start_occurence > available_occurences
    warning('loadDspInputFromFilePaths:StartOccurrenceTooHigh', ...
        ['Requested start_occurence %d, but only %d synced occurrences are available. ', ...
        'Processing the last occurrence only.'], ...
        start_occurence, available_occurences);
    Scpe_cell = Scpe_cell(available_occurences);
    return
end

stop_occurence = min(available_occurences, start_occurence + max_occurences - 1);
Scpe_cell = Scpe_cell(start_occurence:stop_occurence);
end

function value = getOption(options, name, defaultValue)
if isfield(options, name)
    value = options.(name);
else
    value = defaultValue;
end
end