path: root/ui/ui.go

package ui

import (
	"errors"
	"fmt"
	"log"
	"os"
	"strings"

	"github.com/charmbracelet/bubbles/spinner"
	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/charm"
	"github.com/charmbracelet/charm/ui/common"
	"github.com/muesli/gitcha"
	te "github.com/muesli/termenv"
)

const (
	noteCharacterLimit = 256 // should match server
)

// UIConfig contains flags for debugging the TUI.
type UIConfig struct {
	Logfile              string `env:"GLOW_UI_LOGFILE"`
	HighPerformancePager bool   `env:"GLOW_UI_HIGH_PERFORMANCE_PAGER" default:"true"`
	GlamourEnabled       bool   `env:"GLOW_UI_ENABLE_GLAMOUR" default:"true"`
}

var (
	config            UIConfig
	glowLogoTextColor = common.Color("#ECFD65")
)

// NewProgram returns a new Tea program
func NewProgram(style string, cfg UIConfig) *tea.Program {
	config = cfg
	if config.Logfile != "" {
		log.Println("-- Starting Glow ----------------")
		log.Printf("High performance pager: %v", cfg.HighPerformancePager)
		log.Printf("Glamour rendering: %v", cfg.GlamourEnabled)
		log.Println("Bubble Tea now initializing...")
	}
	return tea.NewProgram(initialize(style), update, view)
}

// MESSAGES

type errMsg error
type newCharmClientMsg *charm.Client
type sshAuthErrMsg struct{}
type keygenFailedMsg struct{}
type keygenSuccessMsg struct{}
type initLocalFileSearchMsg struct {
	cwd string
	ch  chan string
}
type foundLocalFileMsg string
type localFileSearchFinished struct{}
type gotStashMsg []*charm.Markdown
type stashLoadErrMsg struct{ err error }
type gotNewsMsg []*charm.Markdown
type newsLoadErrMsg struct{ err error }

// MODEL

type state int

const (
	stateShowStash state = iota
	stateShowDocument
)

type keygenState int

const (
	keygenUnstarted keygenState = iota
	keygenRunning
	keygenFinished
)

// String translates the staus to a human-readable string. This is just for
// debugging.
func (s state) String() string {
	return [...]string{
		"initializing",
		"running keygen",
		"keygen finished",
		"showing stash",
		"showing document",
	}[s]
}

type model struct {
	cc             *charm.Client
	user           *charm.User
	keygenState    keygenState
	state          state
	fatalErr       error
	stash          stashModel
	pager          pagerModel
	terminalWidth  int
	terminalHeight int
	cwd            string // directory from which we're running Glow

	// Channel that receives paths to local markdown files
	// (via the github.com/muesli/gitcha package)
	localFileFinder chan string
}

func (m *model) unloadDocument() {
	m.state = stateShowStash
	m.stash.state = stashStateReady
	m.pager.unload()
	m.pager.showHelp = false
}

// INIT

func initialize(style string) func() (tea.Model, tea.Cmd) {
	return func() (tea.Model, tea.Cmd) {
		if style == "auto" {
			dbg := te.HasDarkBackground()
			if dbg == true {
				style = "dark"
			} else {
				style = "light"
			}
		}

		m := model{
			stash:       newStashModel(),
			pager:       newPagerModel(style),
			state:       stateShowStash,
			keygenState: keygenUnstarted,
		}

		return m, tea.Batch(
			findLocalFiles,
			newCharmClient,
			spinner.Tick(m.stash.spinner),
		)
	}
}

// UPDATE

func update(msg tea.Msg, mdl tea.Model) (tea.Model, tea.Cmd) {
	m, ok := mdl.(model)
	if !ok {
		return model{
			fatalErr: errors.New("could not perform assertion on model in update"),
		}, tea.Quit
	}

	// If there's been an error, any key exits
	if m.fatalErr != nil {
		if _, ok := msg.(tea.KeyMsg); ok {
			return m, tea.Quit
		}
	}

	var cmds []tea.Cmd

	switch msg := msg.(type) {
	case tea.KeyMsg:
		switch msg.String() {
		case "q":
			fallthrough
		case "esc":
			var cmd tea.Cmd

			// Send these keys through to stash
			switch m.state {
			case stateShowStash:

				switch m.stash.state {
				case stashStateSettingNote, stashStatePromptDelete, stashStateShowingError:
					m.stash, cmd = stashUpdate(msg, m.stash)
					return m, cmd
				}

			// Special cases for the pager
			case stateShowDocument:
				var batch []tea.Cmd
				if m.pager.state == pagerStateBrowse {
					// If the user is just browing a document, exit the pager.
					m.unloadDocument()
					if m.pager.viewport.HighPerformanceRendering {
						batch = append(batch, tea.ClearScrollArea)
					}
					if !m.stash.loaded.done() || m.stash.loadingFromNetwork {
						batch = append(batch, spinner.Tick(m.stash.spinner))
					}
				} else {
					// Otherwise send these key messages through to pager for
					// processing
					newPagerModel, cmd := pagerUpdate(msg, m.pager)
					m.pager = newPagerModel
					cmds = append(batch, cmd)
				}
				return m, tea.Batch(batch...)
			}

			return m, tea.Quit

		// Ctrl+C always quits no matter where in the application you are.
		case "ctrl+c":
			return m, tea.Quit

		// Repaint
		case "ctrl+l":
			// TODO
			return m, nil
		}

	// Window size is received when starting up and on every resize
	case tea.WindowSizeMsg:
		m.terminalWidth = msg.Width
		m.terminalHeight = msg.Height
		m.stash.setSize(msg.Width, msg.Height)
		m.pager.setSize(msg.Width, msg.Height)

		// TODO: load more stash pages if we've resized, are on the last page,
		// and haven't loaded more pages yet.

	// We've started looking for local files
	case initLocalFileSearchMsg:
		m.localFileFinder = msg.ch
		m.cwd = msg.cwd
		cmds = append(cmds, findNextLocalFile(m))

	// We found a local file
	case foundLocalFileMsg:
		pathStr, err := localFileToMarkdown(m.cwd, string(msg))
		if err == nil {
			m.stash.addMarkdowns(pathStr)
		}
		cmds = append(cmds, findNextLocalFile(m))

	case sshAuthErrMsg:
		// If we haven't run the keygen yet, do that
		if m.keygenState != keygenFinished {
			m.keygenState = keygenRunning
			cmds = append(cmds, generateSSHKeys)
		} else {
			// The keygen ran but things still didn't work and we can't auth
			m.stash.err = errors.New("SSH authentication failed; we tried ssh-agent, loading keys from disk, and generating SSH keys")

			// Even though it failed, news/stash loading is finished
			m.stash.loaded |= loadedStash | loadedNews
			m.stash.loadingFromNetwork = false
		}

	case keygenFailedMsg:
		// Keygen failed. That sucks.
		m.stash.err = errors.New("could not authenticate; could not generate SSH keys")
		m.keygenState = keygenFinished

		// Even though it failed, news/stash loading is finished
		m.stash.loaded |= loadedStash | loadedNews