// Package tui is the interactive Bubble Tea configurator. It is meant to be
// run over SSH on the headless Pi: browse cameras, assign them to layout
// slots, pick the active layout, discover cameras from UniFi Protect, and save
// — signalling the running daemon to reload on save.
package tui

import (
	"context"
	"fmt"

	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"
	"github.com/lwoodard/rtsp-streamer/internal/config"
	"github.com/lwoodard/rtsp-streamer/internal/ipc"
	"github.com/lwoodard/rtsp-streamer/internal/protect"
)

type screen int

const (
	screenMenu screen = iota
	screenCameras
	screenLayouts
	screenLayoutEdit
	screenCameraPicker
	screenSetActive
)

var (
	titleStyle  = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("62")).Padding(0, 1)
	cursorStyle = lipgloss.NewStyle().Foreground(lipgloss.Color("205"))
	dimStyle    = lipgloss.NewStyle().Foreground(lipgloss.Color("240"))
	okStyle     = lipgloss.NewStyle().Foreground(lipgloss.Color("35"))
	errStyle    = lipgloss.NewStyle().Foreground(lipgloss.Color("203"))
	// helpStyle adapts to light/dark terminals so it stays legible on both.
	helpStyle = lipgloss.NewStyle().
			Foreground(lipgloss.AdaptiveColor{Light: "238", Dark: "251"}).MarginTop(1)
	// keyStyle accents the key names inside help lines.
	keyStyle = lipgloss.NewStyle().Bold(true).
			Foreground(lipgloss.AdaptiveColor{Light: "26", Dark: "81"})
	// usedStyle marks cameras already placed in the current layout.
	usedStyle = lipgloss.NewStyle().Foreground(lipgloss.Color("35"))
	// cursorCellStyle highlights the selected grid cell in the layout editor.
	cursorCellStyle = lipgloss.NewStyle().Foreground(lipgloss.Color("0")).Background(lipgloss.Color("205"))
)

// hkey formats "<key> <desc>" with the key accented, for help lines.
func hkey(key, desc string) string {
	return keyStyle.Render(key) + " " + desc
}

type model struct {
	cfgPath string
	cfg     *config.Config
	dirty   bool

	screen screen
	cursor int

	editLayout   int // index into cfg.Layouts for edit/picker screens
	edCol, edRow int // grid-editor cursor position

	status  string
	isError bool
}

// Run loads the config and starts the TUI event loop.
func Run(cfgPath string) error {
	cfg, err := config.Load(cfgPath)
	if err != nil {
		return err
	}
	m := &model{cfgPath: cfgPath, cfg: cfg, screen: screenMenu}
	_, err = tea.NewProgram(m, tea.WithAltScreen()).Run()
	return err
}

func (m *model) Init() tea.Cmd { return nil }

// ---- messages ----

type discoverMsg struct {
	cams    []protect.Camera
	enabled int // count of cameras we turned RTSP on for
	err     error
}

type savedMsg struct {
	err      error
	reloaded bool
}

// discoverCmd fetches cameras. When enable is non-empty (e.g. "high"), it also
// turns on RTSP in Protect for any camera that lacks an enabled channel.
func (m *model) discoverCmd(enable string) tea.Cmd {
	cfg := m.cfg
	return func() tea.Msg {
		if cfg.Controller.Host == "" {
			return discoverMsg{err: fmt.Errorf("controller.host is not set")}
		}
		pw := cfg.Controller.ResolvePassword()
		if pw == "" {
			return discoverMsg{err: fmt.Errorf("no controller password available")}
		}
		cl, err := protect.New(cfg.Controller.Host, cfg.Controller.RTSPPort, cfg.Controller.VerifyTLS)
		if err != nil {
			return discoverMsg{err: err}
		}
		ctx := context.Background()
		if err := cl.Login(ctx, cfg.Controller.Username, pw); err != nil {
			return discoverMsg{err: err}
		}
		cams, err := cl.Cameras(ctx)
		if err != nil {
			return discoverMsg{err: err}
		}
		enabled := 0
		if enable != "" {
			names, _ := cl.EnableMissing(ctx, cams, enable)
			enabled = len(names)
		}
		return discoverMsg{cams: cams, enabled: enabled}
	}
}

// ---- update ----

func (m *model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case discoverMsg:
		return m.handleDiscover(msg)
	case savedMsg:
		if msg.err != nil {
			m.setStatus("save failed: "+msg.err.Error(), true)
			return m, nil
		}
		m.dirty = false
		if msg.reloaded {
			m.setStatus("saved and reloaded the running daemon", false)
		} else {
			m.setStatus("saved to "+m.cfgPath, false)
		}
		return m, nil
	case tea.KeyMsg:
		return m.handleKey(msg)
	}
	return m, nil
}

func (m *model) handleDiscover(msg discoverMsg) (tea.Model, tea.Cmd) {
	if msg.err != nil {
		m.setStatus("discover failed: "+msg.err.Error(), true)
		return m, nil
	}
	cl, _ := protect.New(m.cfg.Controller.Host, m.cfg.Controller.RTSPPort, m.cfg.Controller.VerifyTLS)
	added, updated, skipped := 0, 0, 0
	for _, cam := range msg.cams {
		ch := cam.BestEnabledChannel()
		if ch == nil {
			skipped++
			continue
		}
		url := cl.StreamURL(ch.RTSPAlias)
		if ex := m.cameraByID(cam.ID); ex != nil {
			ex.Name, ex.RTSP = cam.Name, url
			updated++
		} else if ex := m.cfg.CameraByName(cam.Name); ex != nil {
			ex.ID, ex.RTSP = cam.ID, url
			updated++
		} else {
			m.cfg.Cameras = append(m.cfg.Cameras, config.Camera{ID: cam.ID, Name: cam.Name, RTSP: url})
			added++
		}
	}
	m.dirty = true
	enabledNote := ""
	if msg.enabled > 0 {
		enabledNote = fmt.Sprintf(", enabled RTSP on %d", msg.enabled)
	}
	m.setStatus(fmt.Sprintf("discovered %d (%d new, %d updated, %d without RTSP%s)", len(msg.cams), added, updated, skipped, enabledNote), false)
	m.screen = screenCameras
	m.cursor = 0
	return m, nil
}

func (m *model) handleKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
	switch msg.String() {
	case "ctrl+c":
		return m, tea.Quit
	}
	switch m.screen {
	case screenMenu:
		return m.updateMenu(msg)
	case screenCameras:
		return m.updateCameras(msg)
	case screenLayouts:
		return m.updateLayouts(msg)
	case screenLayoutEdit:
		return m.updateLayoutEdit(msg)
	case screenCameraPicker:
		return m.updateCameraPicker(msg)
	case screenSetActive:
		return m.updateSetActive(msg)
	}
	return m, nil
}

// menu -------------------------------------------------------------

const (
	menuCameras = iota
	menuLayouts
	menuSetActive
	menuDiscover
	menuDiscoverEnable
	menuSave
	menuQuit
)

var menuItems = []string{
	menuCameras:        "Cameras",
	menuLayouts:        "Layouts",
	menuSetActive:      "Set active layout",
	menuDiscover:       "Discover from UniFi Protect",
	menuDiscoverEnable: "Discover + enable RTSP (high)",
	menuSave:           "Save",
	menuQuit:           "Quit",
}

func (m *model) updateMenu(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
	switch msg.String() {
	case "up", "k":
		m.moveCursor(-1, len(menuItems))
	case "down", "j":
		m.moveCursor(1, len(menuItems))
	case "enter", "l", " ":
		switch m.cursor {
		case menuCameras:
			m.screen, m.cursor = screenCameras, 0
		case menuLayouts:
			m.screen, m.cursor = screenLayouts, 0
		case menuSetActive:
			m.screen, m.cursor = screenSetActive, 0
		case menuDiscover:
			m.setStatus("discovering…", false)
			return m, m.discoverCmd("")
		case menuDiscoverEnable:
			m.setStatus("discovering and enabling RTSP…", false)
			return m, m.discoverCmd("high")
		case menuSave:
			return m, m.save()
		case menuQuit:
			return m, m.quit()
		}
	case "q":
		return m, m.quit()
	}
	return m, nil
}

// cameras ----------------------------------------------------------

func (m *model) updateCameras(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
	n := len(m.cfg.Cameras)
	switch msg.String() {
	case "esc", "backspace", "h":
		m.screen, m.cursor = screenMenu, 0
	case "up", "k":
		m.moveCursor(-1, n)
	case "down", "j":
		m.moveCursor(1, n)
	case "d":
		if n > 0 {
			m.cfg.Cameras[m.cursor].Disabled = !m.cfg.Cameras[m.cursor].Disabled
			m.dirty = true
		}
	case "x":
		if n > 0 {
			m.cfg.Cameras = append(m.cfg.Cameras[:m.cursor], m.cfg.Cameras[m.cursor+1:]...)
			if m.cursor >= len(m.cfg.Cameras) && m.cursor > 0 {
				m.cursor--
			}
			m.dirty = true
		}
	}
	return m, nil
}

// layouts ----------------------------------------------------------

func (m *model) updateLayouts(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
	n := len(m.cfg.Layouts)
	switch msg.String() {
	case "esc", "backspace", "h":
		m.screen, m.cursor = screenMenu, 0
	case "up", "k":
		m.moveCursor(-1, n)
	case "down", "j":
		m.moveCursor(1, n)
	case "enter", "l":
		if n > 0 {
			m.editLayout = m.cursor
			m.migrateToTiles(m.editLayout)
			m.edCol, m.edRow = 0, 0
			m.screen, m.cursor = screenLayoutEdit, 0
		}
	}
	return m, nil
}

// (grid-editor update logic lives in gridedit.go)

// camera picker ----------------------------------------------------

// pickerOptions is "(empty)" followed by enabled camera names.
func (m *model) pickerOptions() []string {
	opts := []string{"(empty)"}
	for _, c := range m.cfg.Cameras {
		if c.Disabled {
			continue
		}
		opts = append(opts, c.Name)
	}
	return opts
}

func (m *model) updateCameraPicker(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
	opts := m.pickerOptions()
	switch msg.String() {
	case "esc", "backspace", "h":
		m.screen, m.cursor = screenLayoutEdit, 0
	case "up", "k":
		m.moveCursor(-1, len(opts))
	case "down", "j":
		m.moveCursor(1, len(opts))
	case "enter", "l":
		choice := ""
		if m.cursor > 0 {
			choice = opts[m.cursor]
		}
		m.assignCamera(choice)
		m.screen, m.cursor = screenLayoutEdit, 0
	}
	return m, nil
}

// set active -------------------------------------------------------

func (m *model) updateSetActive(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
	n := len(m.cfg.Layouts)
	switch msg.String() {
	case "esc", "backspace", "h":
		m.screen, m.cursor = screenMenu, 0
	case "up", "k":
		m.moveCursor(-1, n)
	case "down", "j":
		m.moveCursor(1, n)
	case "enter", "l":
		if n > 0 {
			m.cfg.ActiveLayout = m.cfg.Layouts[m.cursor].Name
			m.dirty = true
			m.setStatus("active layout set to "+m.cfg.ActiveLayout, false)
			m.screen, m.cursor = screenMenu, 0
		}
	}
	return m, nil
}

// helpers ----------------------------------------------------------

func (m *model) moveCursor(delta, n int) {
	if n == 0 {
		m.cursor = 0
		return
	}
	m.cursor = (m.cursor + delta + n) % n
}

func (m *model) cameraByID(id string) *config.Camera {
	if id == "" {
		return nil
	}
	for i := range m.cfg.Cameras {
		if m.cfg.Cameras[i].ID == id {
			return &m.cfg.Cameras[i]
		}
	}
	return nil
}

func (m *model) setStatus(s string, isErr bool) {
	m.status, m.isError = s, isErr
}

func (m *model) save() tea.Cmd {
	cfgPath, cfg := m.cfgPath, m.cfg
	return func() tea.Msg {
		if err := config.Save(cfgPath, cfg); err != nil {
			return savedMsg{err: err}
		}
		// Best-effort: tell a running daemon to reload.
		_, err := ipc.Send(ipc.Request{Cmd: "reload"})
		return savedMsg{reloaded: err == nil}
	}
}

func (m *model) quit() tea.Cmd {
	return tea.Quit
}