package main

import (
	"os/exec"
	"strconv"

	"github.com/zyedidia/tcell"
	"github.com/zyedidia/terminal"
)

const (
	VTIdle    = iota // Waiting for a new command
	VTRunning        // Currently running a command
	VTDone           // Finished running a command
)

// A Terminal holds information for the terminal emulator
type Terminal struct {
	state  terminal.State
	term   *terminal.VT
	title  string
	status int
}

// Start begins a new command in this terminal with a given view
func (t *Terminal) Start(execCmd []string, view *View) error {
	if len(execCmd) <= 0 {
		return nil
	}

	cmd := exec.Command(execCmd[0], execCmd[1:]...)
	term, _, err := terminal.Start(&t.state, cmd)
	if err != nil {
		return err
	}
	t.term = term
	t.status = VTRunning
	t.title = execCmd[0] + ":" + strconv.Itoa(cmd.Process.Pid)

	go func() {
		for {
			err := term.Parse()
			if err != nil {
				break
			}
			updateterm <- true
		}
		closeterm <- view.Num
	}()

	return nil
}

// Resize informs the terminal of a resize event
func (t *Terminal) Resize(width, height int) {
	t.term.Resize(width, height)
}

// Stop stops execution of the terminal and sets the status
// to VTDone
func (t *Terminal) Stop() {
	t.term.File().Close()
	t.term.Close()
	t.status = VTDone
}

// Close sets the status to VTIdle indicating that the terminal
// is ready for a new command to execute
func (t *Terminal) Close() {
	t.status = VTIdle
}

// WriteString writes a given string to this terminal's pty
func (t *Terminal) WriteString(str string) {
	t.term.File().WriteString(str)
}

// Display displays this terminal in a view
func (t *Terminal) Display(v *View) {
	divider := 0
	if v.x != 0 {
		divider = 1
		dividerStyle := defStyle
		if style, ok := colorscheme["divider"]; ok {
			dividerStyle = style
		}
		for i := 0; i < v.Height; i++ {
			screen.SetContent(v.x, v.y+i, '|', nil, dividerStyle.Reverse(true))
		}
	}
	t.state.Lock()
	defer t.state.Unlock()

	for y := 0; y < v.Height; y++ {
		for x := 0; x < v.Width; x++ {

			c, f, b := t.state.Cell(x, y)

			fg, bg := int(f), int(b)
			if f == terminal.DefaultFG {
				fg = int(tcell.ColorDefault)
			}
			if b == terminal.DefaultBG {
				bg = int(tcell.ColorDefault)
			}
			st := tcell.StyleDefault.Foreground(GetColor256(int(fg))).Background(GetColor256(int(bg)))

			screen.SetContent(v.x+x+divider, v.y+y, c, nil, st)
		}
	}
	if t.state.CursorVisible() && tabs[curTab].CurView == v.Num {
		curx, cury := t.state.Cursor()
		screen.ShowCursor(curx+v.x+divider, cury+v.y)
	}
}