/**
 * API layer for Calendink Provider ESP32-S3 dashboard.
 *
 * VITE_API_BASE controls the backend URL:
 * - Development (PC): "http://<ESP32_IP>" (set in .env.development)
 * - Production (ESP32): "" (empty = relative URLs, same origin)
 */

const API_BASE = import.meta.env.VITE_API_BASE || '';

/**
 * Fetch system information from the ESP32.
 * @returns {Promise<{chip: string, freeHeap: number, uptime: number, firmware: string, connection: string}>}
 */
export async function getSystemInfo() {
    const res = await fetch(`${API_BASE}/api/system/info`);
    if (!res.ok) {
        throw new Error(`HTTP ${res.status}: ${res.statusText}`);
    }
    const data = await res.json();
    return {
        ...data,
        freeHeap: data.free_heap
    };
}

/**
 * Send a reboot command to the ESP32.
 * @returns {Promise<{message: string}>}
 */
export async function reboot() {
    const res = await fetch(`${API_BASE}/api/system/reboot`, {
        method: 'POST',
    });
    if (!res.ok) {
        throw new Error(`HTTP ${res.status}: ${res.statusText}`);
    }
    return res.json();
}

/**
 * Fetch OTA status from the ESP32.
 * @returns {Promise<{active_slot: number, active_partition: string, target_partition: string}>}
 */
export async function getOTAStatus() {
    const res = await fetch(`${API_BASE}/api/ota/status`);
    if (!res.ok) {
        throw new Error(`HTTP ${res.status}: ${res.statusText}`);
    }
    return res.json();
}

/**
 * Upload a new frontend binary image.
 * @param {File} file The binary file to upload.
 * @returns {Promise<{status: string, message: string}>}
 */
export async function uploadOTAFrontend(file) {
    const res = await fetch(`${API_BASE}/api/ota/frontend`, {
        method: 'POST',
        body: file, // Send the raw file Blob/Buffer
        headers: {
            // Let the browser set Content-Type for the binary payload, 
            // or we could force application/octet-stream.
            'Content-Type': 'application/octet-stream'
        }
    });
    
    if (!res.ok) {
        const errorText = await res.text();
        throw new Error(`Upload failed (${res.status}): ${errorText || res.statusText}`);
    }
    
    return res.json();
}