cli

type App interface {
	// MutateState mutates the state of the app.
	MutateState(f func(*State))
	// CopyState returns a copy of the a state.
	CopyState() State
	// CodeArea returns the codearea widget of the app.
	CodeArea() CodeArea
	// ReadCode requests the App to read code from the terminal by running an
	// event loop. This function is not re-entrant.
	ReadCode() (string, error)
	// Redraw requests a redraw. It never blocks and can be called regardless of
	// whether the App is active or not.
	Redraw()
	// RedrawFull requests a full redraw. It never blocks and can be called
	// regardless of whether the App is active or not.
	RedrawFull()
	// CommitEOF causes the main loop to exit with EOF. If this method is called
	// when an event is being handled, the main loop will exit after the handler
	// returns.
	CommitEOF()
	// CommitCode causes the main loop to exit with the current code content. If
	// this method is called when an event is being handled, the main loop will
	// exit after the handler returns.
	CommitCode()
	// Notify adds a note and requests a redraw.
	Notify(note string)
}

type AppSpec struct {
	TTY               TTY
	MaxHeight         func() int
	RPromptPersistent func() bool
	BeforeReadline    []func()
	AfterReadline     []func(string)

	Highlighter Highlighter
	Prompt      Prompt
	RPrompt     Prompt

	OverlayHandler Handler
	Abbreviations  func(f func(abbr, full string))
	QuotePaste     func() bool

	SmallWordAbbreviations func(f func(abbr, full string))

	CodeAreaState CodeAreaState
	State         State
}

type CodeArea interface {
	Widget
	// CopyState returns a copy of the state.
	CopyState() CodeAreaState
	// MutateState calls the given the function while locking StateMutex.
	MutateState(f func(*CodeAreaState))
	// Submit triggers the OnSubmit callback.
	Submit()
}

type CodeAreaSpec struct {
	// A Handler that takes precedence over the default handling of events.
	OverlayHandler Handler
	// A function that highlights the given code and returns any errors it has
	// found when highlighting. If this function is not given, the Widget does
	// not highlight the code nor show any errors.
	Highlighter func(code string) (ui.Text, []error)
	// Prompt callback.
	Prompt func() ui.Text
	// Right-prompt callback.
	RPrompt func() ui.Text
	// A function that calls the callback with string pairs for abbreviations
	// and their expansions. If this function is not given, the Widget does not
	// expand any abbreviations.
	Abbreviations          func(f func(abbr, full string))
	SmallWordAbbreviations func(f func(abbr, full string))
	// A function that returns whether pasted texts (from bracketed pastes)
	// should be quoted. If this function is not given, the Widget defaults to
	// not quoting pasted texts.
	QuotePaste func() bool
	// A function that is called on the submit event.
	OnSubmit func()

	// State. When used in New, this field specifies the initial state.
	State CodeAreaState
}

type CodeAreaState struct {
	Buffer      CodeBuffer
	Pending     PendingCode
	HideRPrompt bool
}

type CodeBuffer struct {
	// Content of the buffer.
	Content string
	// Position of the dot (more commonly known as the cursor), as a byte index
	// into Content.
	Dot int
}

type ColView interface {
	Widget
	// MutateState mutates the state.
	MutateState(f func(*ColViewState))
	// CopyState returns a copy of the state.
	CopyState() ColViewState
	// Left triggers the OnLeft callback.
	Left()
	// Right triggers the OnRight callback.
	Right()
}

type ColViewSpec struct {
	// An overlay handler.
	OverlayHandler Handler
	// A function that takes the number of columns and return weights for the
	// widths of the columns. The returned slice must have a size of n. If this
	// function is nil, all the columns will have the same weight.
	Weights func(n int) []int
	// A function called when the Left method of Widget is called, or when Left
	// is pressed and unhandled.
	OnLeft func(w ColView)
	// A function called when the Right method of Widget is called, or when
	// Right is pressed and unhandled.
	OnRight func(w ColView)

	// State. Specifies the initial state when used in New.
	State ColViewState
}

type ColViewState struct {
	Columns     []Widget
	FocusColumn int
}

type ComboBox interface {
	Widget
	// Returns the embedded codearea widget.
	CodeArea() CodeArea
	// Returns the embedded listbox widget.
	ListBox() ListBox
	// Forces the filtering to rerun.
	Refilter()
}

type ComboBoxSpec struct {
	CodeArea CodeAreaSpec
	ListBox  ListBoxSpec
	OnFilter func(ComboBox, string)
}

type DummyHandler struct{}

type Empty struct{}

type Focuser interface {
	Focus() bool
}

type FuncHandler func(term.Event) bool

type HScrollbar struct {
	Total int
	Low   int
	High  int
}

type HandleTest struct {
	Name   string
	Given  Handler
	Event  term.Event
	Events []term.Event

	WantNewState  interface{}
	WantUnhandled bool
}

type Handler interface {
	// Try to handle a terminal event and returns whether the event has been
	// handled.
	Handle(event term.Event) bool
}

type Highlighter interface {
	// Get returns the highlighted code and any static errors.
	Get(code string) (ui.Text, []error)
	// LateUpdates returns a channel for delivering late updates.
	LateUpdates() <-chan struct{}
}

type Items interface {
	// Show renders the item at the given zero-based index.
	Show(i int) ui.Text
	// Len returns the number of items.
	Len() int
}

type Label struct {
	Content ui.Text
}

type ListBox interface {
	Widget
	// CopyState returns a copy of the state.
	CopyState() ListBoxState
	// Reset resets the state of the widget with the given items and index of
	// the selected item. It triggers the OnSelect callback if the index is
	// valid.
	Reset(it Items, selected int)
	// Select changes the selection by calling f with the current state, and
	// using the return value as the new selection index. It triggers the
	// OnSelect callback if the selected index has changed and is valid.
	Select(f func(ListBoxState) int)
	// Accept accepts the currently selected item.
	Accept()
}

type ListBoxSpec struct {
	// A Handler that takes precedence over the default handling of events.
	OverlayHandler Handler
	// A placeholder to show when there are no items.
	Placeholder ui.Text
	// A function to call when the selected item has changed.
	OnSelect func(it Items, i int)
	// A function called on the accept event.
	OnAccept func(it Items, i int)
	// Whether the listbox should be rendered in a horizontal  Note that
	// in the horizontal layout, items must have only one line.
	Horizontal bool
	// The minimal amount of space to reserve for left and right sides of each
	// entry.
	Padding int
	// If true, the left padding of each item will be styled the same as the
	// first segment of the item, and the right spacing and padding will be
	// styled the same as the last segment of the item.
	ExtendStyle bool

	// State. When used in New, this field specifies the initial state.
	State ListBoxState
}

type ListBoxState struct {
	Items    Items
	Selected int
	First    int
	Height   int
}

type MapHandler map[term.Event]func()

type PendingCode struct {
	// Beginning index of the text area that the pending code replaces, as a
	// byte index into RawState.Code.
	From int
	// End index of the text area that the pending code replaces, as a byte
	// index into RawState.Code.
	To int
	// The content of the pending code.
	Content string
}

type Prompt interface {
	// Trigger requests a re-computation of the prompt. The force flag is set
	// when triggered for the first time during a ReadCode session or after a
	// SIGINT that resets the editor.
	Trigger(force bool)
	// Get returns the current prompt.
	Get() ui.Text
	// LastUpdates returns a channel for notifying late updates.
	LateUpdates() <-chan struct{}
}

type RenderTest struct {
	Name   string
	Given  Renderer
	Width  int
	Height int
	Want   interface{ Buffer() *term.Buffer }
}

type Renderer interface {
	// Render onto a region of bound width and height.
	Render(width, height int) *term.Buffer
}

type State struct {
	// Notes that have been added since the last redraw.
	Notes []string
	// An addon widget. When non-nil, it is shown under the codearea widget and
	// terminal events are handled by it.
	//
	// The addon widget may implement the Focuser interface, in which case the
	// Focus method is used to determine whether the cursor should be placed on
	// the addon widget during each render. If the widget does not implement the
	// Focuser interface, the cursor is always placed on the addon widget.
	Addon Widget
}

type TTY interface {
	// Setup sets up the terminal for the CLI app.
	//
	// This method returns a restore function that undoes the setup, and any
	// error during setup. It only returns fatal errors that make the terminal
	// unsuitable for later operations; non-fatal errors may be reported by
	// showing a warning message, but not returned.
	//
	// This method should be called before any other method is called.
	Setup() (restore func(), err error)

	// ReadEvent reads a terminal event.
	ReadEvent() (term.Event, error)
	// SetRawInput requests the next n ReadEvent calls to read raw events. It
	// is applicable to environments where events are represented as a special
	// sequences, such as VT100. It is a no-op if events are delivered as whole
	// units by the terminal, such as Windows consoles.
	SetRawInput(n int)

	// StopInput causes input delivery to be stopped. When this function
	// returns, the channel previously returned by StartInput will no longer
	// deliver input events.
	StopInput()

	// NotifySignals start relaying signals and returns a channel on which
	// signals are delivered.
	NotifySignals() <-chan os.Signal
	// StopSignals stops the relaying of signals. After this function returns,
	// the channel returned by NotifySignals will no longer deliver signals.
	StopSignals()

	// Size returns the height and width of the terminal.
	Size() (h, w int)

	// Buffer returns the current buffer. The initial value of the current
	// buffer is nil.
	Buffer() *term.Buffer
	// ResetBuffer resets the current buffer to nil without actuating any redraw.
	ResetBuffer()
	// UpdateBuffer updates the current buffer and draw it to the terminal.
	UpdateBuffer(bufNotes, bufMain *term.Buffer, full bool) error
}

type TestItems struct {
	Prefix string
	Style  ui.Styling
	NItems int
}

type TextView interface {
	Widget
	// ScrollBy scrolls the widget by the given delta. Positive values scroll
	// down, and negative values scroll up.
	ScrollBy(delta int)
	// MutateState mutates the state.
	MutateState(f func(*TextViewState))
	// CopyState returns a copy of the State.
	CopyState() TextViewState
}

type TextViewSpec struct {
	// A Handler that takes precedence over the default handling of events.
	OverlayHandler Handler
	// If true, a vertical scrollbar will be shown when there are more lines
	// that can be displayed, and the widget responds to Up and Down keys.
	Scrollable bool
	// State. Specifies the initial state if used in New.
	State TextViewState
}

type TextViewState struct {
	Lines []string
	First int
}

type VScrollbar struct {
	Total int
	Low   int
	High  int
}

type VScrollbarContainer struct {
	Content   Renderer
	Scrollbar VScrollbar
}

type Widget interface {
	Renderer
	Handler
}