// The UI driver.  This is used to interact with the terminal drawing routines.

package ui

// The set of attributes a specific cell can have
type Attribute  uint16

const (
    // Can have only one of these
    ColorDefault Attribute = iota
    ColorBlack
    ColorRed
    ColorGreen
    ColorYellow
    ColorBlue
    ColorMagenta
    ColorCyan
    ColorWhite
)

// and zero or more of these (combined using OR '|')
const (
    AttrBold Attribute = 1 << (iota + 9)
    AttrUnderline
    AttrReverse
)


// Special keys
const (
    KeyF1           rune = 0x8000 + iota
    KeyF2
    KeyF3
    KeyF4
    KeyF5
    KeyF6
    KeyF7
    KeyF8
    KeyF9
    KeyF10
    KeyF11
    KeyF12
    KeyInsert
    KeyDelete
    KeyHome
    KeyEnd
    KeyPgup
    KeyPgdn
    KeyArrowUp
    KeyArrowDown
    KeyArrowLeft
    KeyArrowRight

    KeyCtrlSpace
    KeyCtrlA
    KeyCtrlB
    KeyCtrlC
    KeyCtrlD
    KeyCtrlE
    KeyCtrlF
    KeyCtrlG
    KeyCtrlH
    KeyCtrlI
    KeyCtrlJ
    KeyCtrlK
    KeyCtrlL
    KeyCtrlM
    KeyCtrlN
    KeyCtrlO
    KeyCtrlP
    KeyCtrlQ
    KeyCtrlR
    KeyCtrlS
    KeyCtrlT
    KeyCtrlU
    KeyCtrlV
    KeyCtrlW
    KeyCtrlX
    KeyCtrlY
    KeyCtrlZ
    KeyCtrl3
    KeyCtrl4
    KeyCtrl5
    KeyCtrl6
    KeyCtrl7
    KeyCtrl8
    KeySpace
)

// The type of events supported by the driver
type    EventType   int

const (
    EventNone       EventType   =   iota

    // Event when the window is resized
    EventResize
    
    // Event indicating a key press.  The key is set in Ch
    EventKeyPress
)

// Data from an event callback.
type Event struct {
    Type            EventType
    Ch              rune
}


// The terminal driver interface.
type Driver interface {

    // Initializes the driver.  Returns an error if there was an error
    Init() error

    // Closes the driver
    Close()

    // Returns the size of the window.
    Size() (int, int)

    // Sets the value of a specific cell
    SetCell(x, y int, ch rune, fg, bg Attribute)

    // Synchronizes the internal buffer with the real buffer
    Sync()

    // Wait for an event
    WaitForEvent() Event
}

//