package ui

import (
	"strings"

	"github.com/charmbracelet/bubbles/spinner"
	"github.com/charmbracelet/bubbles/textinput"
	tea "github.com/charmbracelet/bubbletea"

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

// Update behandelt Fenstergröße, Ergebnisse der Hintergrundkommandos und
// Tastendrücke.
func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		m.width, m.height = msg.Width, msg.Height
		m.ready = true
		if w := m.width - 20; w > 10 {
			m.input.Width = w
		}
		if len(m.working) > 0 {
			return m, m.previewCmd() // Breite geändert → Preview neu rendern
		}
		return m, nil

	case spinner.TickMsg:
		var cmd tea.Cmd
		m.spinner, cmd = m.spinner.Update(msg)
		return m, cmd

	case discoverMsg:
		if msg.err != nil {
			m.err = msg.err
			m.current, m.working = nil, nil
			return m, nil
		}
		m.err = nil
		m.current = msg.scripts
		m.host = msg.host
		m.working = rowsFromCurrent(msg.scripts)
		if m.cursor >= len(m.working) {
			m.cursor = max(0, len(m.working)-1)
		}
		m.refreshPresetMatches()
		m.previewOff = 0
		return m, m.previewCmd()

	case presetsMsg:
		if msg.err == nil {
			m.presets = msg.presets
			if m.presetIdx >= len(m.presets) {
				m.presetIdx = max(0, len(m.presets)-1)
			}
			m.refreshPresetMatches()
		}
		return m, nil

	case previewMsg:
		if msg.version < m.previewVersion {
			return m, nil // veraltetes Ergebnis, neuere Preview läuft schon
		}
		m.previewBusy = false
		m.preview = msg.text
		m.previewOff = 0
		return m, nil

	case applyDoneMsg:
		m.applying = false
		if msg.err != nil {
			m.status = "Anwenden fehlgeschlagen: " + msg.err.Error()
		} else {
			m.status = "Angewendet: " + m.lastSummary
		}
		return m, discoverCmd(m.root)

	case tea.KeyMsg:
		return m.handleKey(msg)
	}
	return m, nil
}

func (m Model) handleKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
	switch m.mode {
	case modeHelp:
		m.mode = modeNormal
		return m, nil

	case modeSaveName:
		switch msg.String() {
		case "enter":
			name := strings.TrimSpace(m.input.Value())
			m.mode = modeNormal
			m.input.Blur()
			if name == "" {
				return m, nil
			}
			if _, err := preset.SaveUser(m.presetFromWorking(name)); err != nil {
				m.status = "Speichern fehlgeschlagen: " + err.Error()
			} else {
				m.status = "Preset \"" + name + "\" gespeichert"
			}
			return m, presetsCmd()
		case "esc", "ctrl+c":
			m.mode = modeNormal
			m.input.Blur()
			return m, nil
		}
		var cmd tea.Cmd
		m.input, cmd = m.input.Update(msg)
		return m, cmd
	}

	key := msg.String()
	switch key {
	case "q", "ctrl+c":
		return m, tea.Quit
	case "tab":
		m.focus = (m.focus + 1) % 3
		return m, nil
	case "shift+tab":
		m.focus = (m.focus + 2) % 3
	case "?":
		m.mode = modeHelp
		return m, nil
	case "r":
		m.status = ""
		return m, discoverCmd(m.root)
	case "esc":
		if m.err != nil {
			return m, tea.Quit
		}
		m.working = rowsFromCurrent(m.current)
		m.previewOff = 0
		m.status = "Änderungen verworfen"
		return m, m.previewCmd()
	case "s":
		if m.err != nil {
			return m, nil
		}
		m.mode = modeSaveName
		m.input.SetValue("")
		m.input.Focus()
		return m, textinput.Blink
	case "a":
		return m.applyWorking()
	case "D":
		if len(m.presets) == 0 {
			return m, nil
		}
		p := m.presets[m.presetIdx]
		if err := preset.DeleteUser(p.Name); err != nil {
			m.status = err.Error()
		} else {
			m.status = "Preset \"" + p.Name + "\" gelöscht"
		}
		return m, presetsCmd()
	}

	switch m.focus {
	case panePresets:
		switch key {
		case "j", "down":
			if m.presetIdx < len(m.presets)-1 {
				m.presetIdx++
			}
		case "k", "up":
			if m.presetIdx > 0 {
				m.presetIdx--
			}
		case "enter", " ":
			return m.loadPreset()
		}

	case paneScripts:
		switch key {
		case "j", "down":
			if m.cursor < len(m.working)-1 {
				m.cursor++
			}
		case "k", "up":
			if m.cursor > 0 {
				m.cursor--
			}
		case " ":
			if len(m.working) == 0 {
				return m, nil
			}
			r := &m.working[m.cursor]
			if r.Remove {
				return m, nil
			}
			r.Enabled = !r.Enabled
			return m, m.previewCmd()
		case "u":
			return m.moveRow(-1)
		case "d":
			return m.moveRow(1)
		}

	case panePreview:
		lines := strings.Count(m.preview, "\n") + 1
		switch key {
		case "j", "down":
			m.previewOff = min(m.previewOff+1, max(0, lines-1))
		case "k", "up":
			if m.previewOff > 0 {
				m.previewOff--
			}
		}
	}
	return m, nil
}

func (m Model) loadPreset() (tea.Model, tea.Cmd) {
	if len(m.presets) == 0 {
		return m, nil
	}
	p := m.presets[m.presetIdx]
	entries := make([]motd.DesiredEntry, 0, len(p.Scripts))
	for _, e := range p.Scripts {
		entries = append(entries, motd.DesiredEntry{Name: e.Name, Enabled: e.Enabled, Install: e.Install})
	}
	m.working = rowsFromDesired(motd.DesiredFromPreset(m.current, entries), m.current)
	m.cursor = 0
	m.previewOff = 0
	m.status = "Preset \"" + p.Name + "\" geladen – mit 'a' anwenden"
	return m, m.previewCmd()
}

func (m Model) moveRow(delta int) (tea.Model, tea.Cmd) {
	i, j := m.cursor, m.cursor+delta
	if i < 0 || i >= len(m.working) || j < 0 || j >= len(m.working) {
		return m, nil
	}
	m.working[i], m.working[j] = m.working[j], m.working[i]
	m.cursor = j
	return m, m.previewCmd()
}

func (m Model) applyWorking() (tea.Model, tea.Cmd) {
	if m.applying || m.err != nil {
		return m, nil
	}
	plan := m.currentPlan()
	if plan.Empty() {
		m.status = "Keine Änderungen zum Anwenden"
		return m, nil
	}
	// Vorlagen-Inhalte jetzt auflösen (User-Templates liegen im eigenen
	// $HOME); der sudo-Prozess kann sie später nicht mehr lesen.
	if err := plan.ResolveContents(); err != nil {
		m.status = err.Error()
		return m, nil
	}
	m.applying = true
	m.lastSummary = plan.Summary()
	return m, applyExec(plan)
}