// preset-manager.js - Verwaltung der Radio-Sender
window.PresetManager = {
    presets: [],

    // Lädt Presets aus LocalStorage oder der JSON-Datei
    async load(callback) {
        this.presets = JSON.parse(localStorage.getItem('presets')) || [];
        if (this.presets.length === 0) {
            try {
                const response = await fetch('webradio_presets.json');
                if (!response.ok) throw new Error('Datei konnte nicht geladen werden');
                this.presets = await response.json();
                this.save();
            } catch (error) {
                if (window.UI) window.UI.showAlert("Fehler", 'Fehler beim Laden der Presets: ' + error.message);
            }
        }
        if (callback) callback(this.presets);
    },

    save() {
        localStorage.setItem('presets', JSON.stringify(this.presets));
    },

    // --- EXPORT/IMPORT (Gzip/Base64) ---
    async generateExportCode() {
        try {
            if (!this.presets || this.presets.length === 0) return;
            const compactData = this.presets.map(p => [p.name, p.url]);
            const jsonString = JSON.stringify(compactData);

            const stream = new Blob([jsonString]).stream();
            const compressedStream = stream.pipeThrough(new CompressionStream('gzip'));
            const response = new Response(compressedStream);
            const buffer = await response.arrayBuffer();
            const base64String = btoa(String.fromCharCode(...new Uint8Array(buffer)));

            const exportField = document.getElementById('export-string-field');
            if (exportField) exportField.value = base64String;
        } catch (e) {
            console.error("Export-Fehler:", e);
        }
    },

    async importFromString(code) {
        try {
            const binary = atob(code);
            const bytes = Uint8Array.from(binary, c => c.charCodeAt(0));
            const stream = new Blob([bytes]).stream();
            const decompressedStream = stream.pipeThrough(new DecompressionStream('gzip'));
            const response = new Response(decompressedStream);
            const resultText = await response.text();

            const importedArray = JSON.parse(resultText);
            this.presets = importedArray.map(item => ({ name: item[0], url: item[1] }));
            this.save();
            location.reload();
        } catch (e) {
            console.error("Import-Fehler:", e);
            if (window.UI) window.UI.showAlert("Fehler", "Code ungültig oder beschädigt!");
        }
    },

    exportToFile() {
        const presetsJSON = JSON.stringify(this.presets, null, 2);
        const blob = new Blob([presetsJSON], { type: 'application/json' });
        const url = URL.createObjectURL(blob);
        const a = document.createElement('a');
        a.href = url;
        a.download = 'radio_presets.json';
        document.body.appendChild(a);
        a.click();
        document.body.removeChild(a);
        URL.revokeObjectURL(url);
    }
};