package main

import (
	"fmt"
	"os/exec"
	"strings"
)

// tmuxCmd runs a tmux command and returns its stdout.
func tmuxCmd(args ...string) (string, error) {
	out, err := exec.Command("tmux", args...).CombinedOutput()
	if err != nil {
		return "", fmt.Errorf("tmux %s: %v: %s", strings.Join(args, " "), err, strings.TrimSpace(string(out)))
	}
	return string(out), nil
}

func tmuxHasSession(name string) bool {
	err := exec.Command("tmux", "has-session", "-t", "="+name).Run()
	return err == nil
}

func tmuxListSessions() []string {
	out, err := tmuxCmd("list-sessions", "-F", "#{session_name}")
	if err != nil {
		return nil // no tmux server running = no sessions
	}
	var names []string
	for _, l := range strings.Split(strings.TrimSpace(out), "\n") {
		if l != "" {
			names = append(names, l)
		}
	}
	return names
}

func tmuxNewSession(name, cwd string, width, height int, cmdline string) error {
	args := []string{"new-session", "-d", "-s", name,
		"-x", fmt.Sprint(width), "-y", fmt.Sprint(height)}
	if cwd != "" {
		args = append(args, "-c", cwd)
	}
	if cmdline != "" {
		args = append(args, cmdline)
	}
	_, err := tmuxCmd(args...)
	return err
}

func tmuxKillSession(name string) error {
	_, err := tmuxCmd("kill-session", "-t", "="+name)
	return err
}

// tmuxCapture returns the visible pane content. ansi keeps escape
// sequences (for terminal-faithful rendering in clients).
func tmuxCapture(name string, ansi bool, history int) (string, error) {
	args := []string{"capture-pane", "-p", "-t", "=" + name + ":"}
	if ansi {
		args = append(args, "-e")
	}
	if history > 0 {
		args = append(args, "-S", fmt.Sprintf("-%d", history))
	}
	return tmuxCmd(args...)
}

// tmuxSendKeys sends key names (Enter, Up, Down, BTab, C-c, ...).
func tmuxSendKeys(name string, keys ...string) error {
	args := append([]string{"send-keys", "-t", "=" + name + ":"}, keys...)
	_, err := tmuxCmd(args...)
	return err
}

// tmuxPasteText inserts literal text (multi-line safe) via a paste
// buffer, without submitting it.
func tmuxPasteText(name, text string) error {
	cmd := exec.Command("tmux", "load-buffer", "-b", "helmd", "-")
	cmd.Stdin = strings.NewReader(text)
	if out, err := cmd.CombinedOutput(); err != nil {
		return fmt.Errorf("tmux load-buffer: %v: %s", err, strings.TrimSpace(string(out)))
	}
	_, err := tmuxCmd("paste-buffer", "-d", "-b", "helmd", "-t", "="+name+":")
	return err
}

func tmuxSessionAlive(name string) bool {
	out, err := tmuxCmd("list-panes", "-t", "="+name+":", "-F", "#{pane_dead}")
	if err != nil {
		return false
	}
	return strings.TrimSpace(out) == "0"
}