package I2C

import (
    "time"
    "fmt"
)

func NewMonitor(b int) *I2CMonitor{
    m := new(I2CMonitor)
    m.Devices = make(map[int]I2Cdev)
    m.Bus = b
    m.Update() //ensure that devices get updated before it gets locked by connected
    return m
}

func (m *I2CMonitor) Update() {
    /*
    gets newly connected sensors and updates any currently dead sensors
    */
    m.mu.Lock()
    defer m.mu.Unlock()
    // locking right away should be fine
    fmt.Printf("Getting devices on bus %v\n",m.Bus)
    connected := I2Cconnected(m.Bus)
    // m.mu.Lock()
    // defer m.mu.Unlock()
    now := time.Now()
    for k,v := range connected {
        if _, ok := m.Devices[k]; ok {   // if address existed
            entry := m.Devices[k]
            entry.Active = v             // update the value
            if v {
                entry.LastSeen = now     // if its active, update last seen time
            }
            m.Devices[k] = entry
        } else if v {                           // else theres a chance its new
            fmt.Printf("adding device %v\n",k)
            m.Devices[k] = I2Cdev{Active:true, LastSeen:now} // add new sensors
        }
    }
}

func (m *I2CMonitor) Remove(addr int) {
    m.mu.Lock()
    defer m.mu.Unlock()
    delete(m.Devices, addr)
}

func (m *I2CMonitor) Connected() []int {
    // returns list of addresses of connected devices
    m.mu.Lock()
    defer m.mu.Unlock()
    connected := []int{}
    for a,_ := range m.Devices {
        connected = append(connected, a)
    }
    return connected