package dal

import (
	"context"
	"database/sql"
	"time"
)

type ChamberState int

const (
	ChamberStateIdle = iota
	ChamberStateCooling
	ChamberStateHeating
)

type TemperatureReadingDto struct {
	Time   time.Time
	Sensor string
	Value  int
}

type ChamberStateChangeDto struct {
	Time  time.Time
	State ChamberState
}

func LoadTemperatureReadingsSince(ctx context.Context, tx *sql.Tx, since time.Time) ([]TemperatureReadingDto, error) {
	q := `
	SELECT
		c_time,
		sensor,
		value
	FROM temperature_reading
	WHERE
		c_time > ?
	ORDER BY c_time
	`
	r, err := tx.QueryContext(ctx, q, since)
	if err != nil {
		return nil, err
	}
	defer r.Close()

	readings := make([]TemperatureReadingDto, 0)
	var reading TemperatureReadingDto
	for r.Next() {
		err = r.Scan(&reading.Time, &reading.Sensor, &reading.Value)
		if err != nil {
			return nil, err
		}

		readings = append(readings, reading)
	}

	return readings, nil
}

func SaveTemperatureReading(ctx context.Context, tx *sql.Tx, sensor string, value int64) error {
	q := "INSERT INTO temperature_reading (sensor, value) VALUES (?, ?)"
	_, err := tx.ExecContext(ctx, q, sensor, value)
	return err
}

func SaveChamberState(ctx context.Context, tx *sql.Tx, state ChamberState) error {
	q := "INSERT INTO state_log (state) VALUES (?)"
	_, err := tx.ExecContext(ctx, q, state)
	return err
}

func LoadLastChamberStateChange(ctx context.Context, tx *sql.Tx) (t time.Time, err error) {
	q := "SELECT c_time FROM state_log ORDER BY c_time DESC LIMIT 1"
	err = tx.QueryRowContext(ctx, q).Scan(&t)
	return
}

func LoadChamberStateChangesSince(ctx context.Context, tx *sql.Tx, since time.Time) ([]ChamberStateChangeDto, error) {
	q := "SELECT c_time, state FROM state_log WHERE c_time > ? ORDER BY c_time"

	r, err := tx.QueryContext(ctx, q, since)
	if err != nil {
		return nil, err
	}
	defer r.Close()

	readings := make([]ChamberStateChangeDto, 0)
	var reading ChamberStateChangeDto
	for r.Next() {
		err = r.Scan(&reading.Time, &reading.Time, &reading.State)
		if err != nil {
			return nil, err
		}

		readings = append(readings, reading)
	}

	return readings, nil
}