package ui

import (
	"os"
	"os/exec"
	"path/filepath"

	tea "github.com/charmbracelet/bubbletea"

	"motd-assist/internal/motd"
	"motd-assist/internal/preset"
)

type discoverMsg struct {
	scripts []motd.Script
	host    motd.HostInfo
	err     error
}

type presetsMsg struct {
	presets []preset.Preset
	err     error
}

type previewMsg struct {
	version int
	text    string
}

type applyDoneMsg struct{ err error }

func discoverCmd(root string) tea.Cmd {
	return func() tea.Msg {
		scripts, err := motd.Discover(root)
		return discoverMsg{scripts: scripts, host: motd.DetectHost(root), err: err}
	}
}

func presetsCmd() tea.Cmd {
	return func() tea.Msg {
		presets, err := preset.LoadAll()
		return presetsMsg{presets: presets, err: err}
	}
}

// previewCmd rendert die Arbeitskopie als Live-Vorschau (asynchron, damit
// langsame Scripte die TUI nicht blockieren).
func (m *Model) previewCmd() tea.Cmd {
	m.previewBusy = true
	m.previewVersion++
	version := m.previewVersion
	width := m.previewWidth()
	scripts := make([]motd.PreviewScript, 0, len(m.working))
	for _, r := range m.working {
		if r.Remove {
			continue
		}
		ps := motd.PreviewScript{Name: r.Name, Enabled: r.Enabled}
		if r.Exists {
			ps.Path = filepath.Join(motd.MotdDir(m.root), r.Name)
		} else {
			ps.Source = r.Install
		}
		scripts = append(scripts, ps)
	}
	return func() tea.Msg {
		return previewMsg{version: version, text: motd.Render(scripts, width)}
	}
}

// previewWidth ist die nutzbare Breite innerhalb der Preview-Umrandung.
func (m *Model) previewWidth() int {
	w := m.width - 4 // Rahmen (2) + Padding (2)
	if w < 40 {
		w = 40
	}
	if w > 100 {
		w = 100
	}
	return w
}

// applyExec handelt das Terminal an sudo weiter (interaktive
// Passwortabfrage) und startet danach die TUI weiter.
func applyExec(plan motd.Plan) tea.Cmd {
	planFile, err := plan.WriteFile()
	if err != nil {
		return func() tea.Msg { return applyDoneMsg{err: err} }
	}
	self, err := os.Executable()
	if err != nil {
		os.Remove(planFile)
		return func() tea.Msg { return applyDoneMsg{err: err} }
	}
	var cmd *exec.Cmd
	if motd.IsRoot() {
		cmd = exec.Command(self, "apply-state", planFile)
	} else {
		sudo, err := exec.LookPath("sudo")
		if err != nil {
			os.Remove(planFile)
			return func() tea.Msg { return applyDoneMsg{err: err} }
		}
		cmd = exec.Command(sudo, "-p", "[motd-assist] Passwort für %p: ", self, "apply-state", planFile)
	}
	return tea.ExecProcess(cmd, func(err error) tea.Msg {
		os.Remove(planFile)
		return applyDoneMsg{err: err}
	})
}