#pragma once

/**
 * Reads the battery level via the ADC voltage divider
 * (CONFIG_FRAME_BATTERY_ADC_GPIO -- see Kconfig for the expected XIAO
 * ESP32-C6 wiring). Returns 0-100, or -1 for any of:
 *   - feature disabled (CONFIG_FRAME_BATTERY_ADC_GPIO < 0),
 *   - running on mains (CONFIG_FRAME_VBUS_SENSE_GPIO reads high),
 *   - reading outside the plausible LiPo range (catches "no battery
 *     attached" and a button held on a shared pin, which reads ~0V),
 *   - any ADC setup/read error.
 *
 * The battery pin is expected to be shared with a button (the settled
 * XIAO design shares the back button's GPIO0/A0): call this AFTER the
 * button checks at boot, since the ADC read temporarily reconfigures
 * the pin. On return the pin is always restored to button duty (input +
 * pull-up + deep-sleep wake armed).
 */
int battery_read_percent(void);