#include <stdbool.h>
#include <stdint.h>
#include <string.h>

#include <app_event_manager.h>

#define MODULE battery_module
#include <caf/events/module_state_event.h>
#include <caf/events/power_manager_event.h>
#include <caf/events/power_event.h>

#include <drivers/pmic/ip5306.h>
#include <zephyr/device.h>
#include <zephyr/devicetree.h>
#include <zephyr/drivers/sensor.h>
#include <zephyr/kernel.h>
#include <zephyr/logging/log.h>
#include <zephyr/pm/device.h>

#include "bat_state_event.h"
#include "module_lifecycle.h"

LOG_MODULE_REGISTER(MODULE, LOG_LEVEL_INF);

#define VBATT_NODE DT_PATH(vbatt)
#define IP5306_NODE DT_NODELABEL(ip5306)
#define BATTERY_SAMPLE_INTERVAL K_SECONDS(1)
#define BATTERY_SOC_MIN_MV 3300
#define BATTERY_SOC_MAX_MV 4200

BUILD_ASSERT(DT_NODE_HAS_STATUS(VBATT_NODE, okay),
	     "Missing /vbatt voltage-divider node in devicetree");
BUILD_ASSERT(DT_NODE_HAS_STATUS(IP5306_NODE, okay),
	     "Missing ip5306 node in devicetree");

struct battery_module_ctx {
	struct module_lifecycle_ctx lc;
	const struct device *vbatt_dev;
	const struct device *ip5306_dev;
	struct k_work_delayable battery_sample_work;
	struct {
		bool valid;
		uint8_t soc;
		bool charging;
		bool full;
	} last_bat_state;
};

static int do_init(void);
static int do_start(void);
static int do_stop(void);

static const struct module_lifecycle_cfg lifecycle_cfg = {
	.mode = ML_MODE_POWER,
	.stopped_state = MODULE_STATE_STANDBY,
};

static const struct module_lifecycle_ops lifecycle_ops = {
	.do_init = do_init,
	.do_start = do_start,
	.do_stop = do_stop,
};

static struct battery_module_ctx ctx = {
	.lc = {
		.state = LC_UNINIT,
		.cfg = &lifecycle_cfg,
		.ops = &lifecycle_ops,
	},
	.vbatt_dev = DEVICE_DT_GET(VBATT_NODE),
	.ip5306_dev = DEVICE_DT_GET(IP5306_NODE),
};

static int sensor_value_to_mv(const struct sensor_value *value)
{
	return (value->val1 * 1000) + (value->val2 / 1000);
}

static int measurement_enable(bool enable)
{
	enum pm_device_action action = enable ? PM_DEVICE_ACTION_RESUME
					      : PM_DEVICE_ACTION_SUSPEND;
	int err = pm_device_action_run(ctx.vbatt_dev, action);

	if (err && (err != -EALREADY) && (err != -ENOTSUP)) {
		LOG_ERR("Cannot %s vbatt sensor (%d)", enable ? "resume" : "suspend", err);
		return err;
	}

	return 0;
}

static uint8_t battery_soc_from_mv(int voltage_mv)
{
	const int span_mv = BATTERY_SOC_MAX_MV - BATTERY_SOC_MIN_MV;
	int bucket;

	if (voltage_mv <= BATTERY_SOC_MIN_MV) {
		return 0U;
	}

	if (voltage_mv >= BATTERY_SOC_MAX_MV) {
		return 100U;
	}

	bucket = ((voltage_mv - BATTERY_SOC_MIN_MV) * 10 + (span_mv / 2)) / span_mv;

	return (uint8_t)(bucket * 10);
}

static void battery_sample_fn(struct k_work *work)
{
	struct ip5306_status pmic_status;
	struct sensor_value voltage;
	int voltage_mv;
	int err;

	ARG_UNUSED(work);

	if (!module_lifecycle_is_running(&ctx.lc)) {
		return;
	}

	err = sensor_sample_fetch(ctx.vbatt_dev);
	if (err) {
		LOG_WRN("Battery sample fetch failed (%d)", err);
		goto reschedule;
	}

	err = sensor_channel_get(ctx.vbatt_dev, SENSOR_CHAN_VOLTAGE, &voltage);
	if (err) {
		LOG_WRN("Battery channel get failed (%d)", err);
		goto reschedule;
	}

	err = ip5306_get_status(ctx.ip5306_dev, &pmic_status);
	if (err) {
		LOG_WRN("IP5306 status read failed (%d)", err);
		goto reschedule;
	}

	voltage_mv = sensor_value_to_mv(&voltage);
	uint8_t soc = battery_soc_from_mv(voltage_mv);

	if (!ctx.last_bat_state.valid ||
	    (ctx.last_bat_state.soc != soc) ||
	    (ctx.last_bat_state.charging != pmic_status.charging) ||
	    (ctx.last_bat_state.full != pmic_status.full)) {
		ctx.last_bat_state.valid = true;
		ctx.last_bat_state.soc = soc;
		ctx.last_bat_state.charging = pmic_status.charging;
		ctx.last_bat_state.full = pmic_status.full;
		submit_bat_state_event(soc, pmic_status.charging, pmic_status.full);
	}

reschedule:
	if (module_lifecycle_is_running(&ctx.lc)) {
		k_work_reschedule(&ctx.battery_sample_work, BATTERY_SAMPLE_INTERVAL);
	}
}

static int do_init(void)
{
	if (!device_is_ready(ctx.vbatt_dev)) {
		LOG_ERR("vbatt device not ready");
		return -ENODEV;
	}

	if (!device_is_ready(ctx.ip5306_dev)) {
		LOG_ERR("ip5306 device not ready");
		return -ENODEV;
	}

	int err = ip5306_init(ctx.ip5306_dev);
	if (err) {
		LOG_ERR("ip5306 init failed (%d)", err);
		return err;
	}

	k_work_init_delayable(&ctx.battery_sample_work, battery_sample_fn);
	memset(&ctx.last_bat_state, 0, sizeof(ctx.last_bat_state));
	power_manager_restrict(MODULE_IDX(MODULE), POWER_MANAGER_LEVEL_SUSPENDED);

	return 0;
}

static int do_start(void)
{
	int err;

	if (module_lifecycle_is_running(&ctx.lc)) {
		return 0;
	}

	err = measurement_enable(true);
	if (err) {
		return err;
	}

	k_work_reschedule(&ctx.battery_sample_work, K_NO_WAIT);

	return 0;
}

static int do_stop(void)
{
	if (!module_lifecycle_is_running(&ctx.lc)) {
		return 0;
	}

	(void)k_work_cancel_delayable(&ctx.battery_sample_work);
	(void)measurement_enable(false);

	return 0;
}

static bool app_event_handler(const struct app_event_header *aeh)
{
	if (is_module_state_event(aeh)) {
		const struct module_state_event *event = cast_module_state_event(aeh);

		if (check_state(event, MODULE_ID(main), MODULE_STATE_READY)) {
			(void)module_set_lifecycle(&ctx.lc, LC_RUNNING);
		}

		return false;
	}

	if (is_power_down_event(aeh)) {
		if (module_lifecycle_is_initialized(&ctx.lc)) {
			(void)module_set_lifecycle(&ctx.lc, LC_STOPPED);
		}

		return false;
	}

	if (is_wake_up_event(aeh)) {
		if (module_lifecycle_is_initialized(&ctx.lc)) {
			(void)module_set_lifecycle(&ctx.lc, LC_RUNNING);
		}

		return false;
	}

	__ASSERT_NO_MSG(false);
	return false;
}

APP_EVENT_LISTENER(MODULE, app_event_handler);
APP_EVENT_SUBSCRIBE(MODULE, module_state_event);
APP_EVENT_SUBSCRIBE_EARLY(MODULE, power_down_event);
APP_EVENT_SUBSCRIBE(MODULE, wake_up_event);