reddit-reader/internal/tui/views.go

package tui

import (
	"fmt"
	"strings"
	"time"

	"github.com/charmbracelet/lipgloss"
	"somegit.dev/vikingowl/reddit-reader/internal/domain"
)

var (
	titleStyle   = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("39"))
	tabStyle     = lipgloss.NewStyle().Padding(0, 2)
	activeTab    = tabStyle.Copy().Foreground(lipgloss.Color("39")).Bold(true).Underline(true)
	dimStyle     = lipgloss.NewStyle().Foreground(lipgloss.Color("240"))
	scoreStyle   = lipgloss.NewStyle().Foreground(lipgloss.Color("220"))
	cursorStyle  = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("212"))
	summaryStyle = lipgloss.NewStyle().Padding(0, 2).Foreground(lipgloss.Color("252"))
	helpStyle    = dimStyle.Copy().Padding(1, 0)
	errorStyle   = lipgloss.NewStyle().Foreground(lipgloss.Color("196"))
)

const (
	headerLines = 2 // tab bar + blank line
	helpLines   = 2 // blank line + help bar
	detailLines = 8 // approximate lines for expanded detail pane
)

// renderView is the top-level renderer called by Model.View().
func renderView(m Model) string {
	if m.err != nil {
		return errorStyle.Render(fmt.Sprintf("error: %v", m.err)) + "\n" +
			helpStyle.Render("q quit")
	}

	var b strings.Builder

	b.WriteString(renderTabs(m.view))
	b.WriteString("\n")

	if m.view == viewSettings {
		b.WriteString(summaryStyle.Render("Settings — edit ~/.config/reddit-reader/config.toml"))
		b.WriteString("\n")
		b.WriteString(helpStyle.Render("tab next view  •  q quit"))
		return b.String()
	}

	visible := filterForView(m.posts, m.view)

	if len(visible) == 0 {
		b.WriteString(dimStyle.Render("  (empty)"))
		b.WriteString("\n")
	} else {
		// Calculate how many list rows fit given terminal height.
		listHeight := m.height - headerLines - helpLines
		if m.expanded {
			listHeight -= detailLines
		}
		if listHeight < 1 {
			listHeight = 1
		}

		// Scroll window: keep cursor visible.
		start := 0
		if m.cursor >= listHeight {
			start = m.cursor - listHeight + 1
		}
		end := start + listHeight
		if end > len(visible) {
			end = len(visible)
		}

		for i := start; i < end; i++ {
			selected := i == m.cursor
			b.WriteString(renderPostLine(visible[i], selected))
			b.WriteString("\n")
		}

		// Expanded detail pane for the selected post.
		if m.expanded && m.cursor < len(visible) {
			b.WriteString(renderDetail(visible[m.cursor]))
			b.WriteString("\n")
		}
	}

	b.WriteString(helpStyle.Render(
		"j/k navigate  •  enter expand  •  s star  •  d dismiss  •  o open  •  +/- vote  •  tab view  •  q quit",
	))

	return b.String()
}

// renderTabs renders the tab bar.
func renderTabs(current view) string {
	var parts []string
	for i, name := range viewNames {
		if view(i) == current {
			parts = append(parts, activeTab.Render(name))
		} else {
			parts = append(parts, tabStyle.Render(name))
		}
	}
	return titleStyle.Render("reddit-reader") + "  " + strings.Join(parts, dimStyle.Render("│"))
}

// renderPostLine renders a single post as a compact one-liner.
// Format: ● r/golang  0.87  2m ago  Title here
func renderPostLine(p domain.Post, selected bool) string {
	bullet := dimStyle.Render("  ·")
	if selected {
		bullet = cursorStyle.Render("  ●")
	}

	subreddit := dimStyle.Render(fmt.Sprintf("r/%-12s", p.Subreddit))

	var relevance string
	if p.Relevance != nil {
		relevance = scoreStyle.Render(fmt.Sprintf("%.2f", *p.Relevance))
	} else {
		relevance = dimStyle.Render("    ")
	}

	age := dimStyle.Render(fmt.Sprintf("%-6s", relativeTime(p.CreatedUTC)))

	title := p.Title
	if p.Starred {
		title = "★ " + title
	}
	if selected {
		title = cursorStyle.Render(title)
	}

	return fmt.Sprintf("%s %s  %s  %s  %s", bullet, subreddit, relevance, age, title)
}

// renderDetail renders the expanded detail pane for a post.
func renderDetail(p domain.Post) string {
	var b strings.Builder

	b.WriteString(summaryStyle.Render(strings.Repeat("─", 60)))
	b.WriteString("\n")
	b.WriteString(summaryStyle.Render(p.Title))
	b.WriteString("\n")
	b.WriteString(summaryStyle.Render(
		fmt.Sprintf("r/%s  •  by u/%s  •  score %d  •  %s", p.Subreddit, p.Author, p.Score, relativeTime(p.CreatedUTC)),
	))
	b.WriteString("\n")
	b.WriteString(summaryStyle.Render(p.URL))
	b.WriteString("\n")

	if p.Summary != nil && *p.Summary != "" {
		b.WriteString("\n")
		for _, line := range strings.Split(*p.Summary, "\n") {
			b.WriteString(summaryStyle.Render("  " + line))
			b.WriteString("\n")
		}
	}

	b.WriteString(summaryStyle.Render(strings.Repeat("─", 60)))

	return b.String()
}

// relativeTime formats a time as a short human-readable age string.
func relativeTime(t time.Time) string {
	if t.IsZero() {
		return "?"
	}
	d := time.Since(t)
	switch {
	case d < time.Minute:
		return "just now"
	case d < time.Hour:
		return fmt.Sprintf("%dm ago", int(d.Minutes()))
	case d < 24*time.Hour:
		return fmt.Sprintf("%dh ago", int(d.Hours()))
	default:
		return fmt.Sprintf("%dd ago", int(d.Hours()/24))
	}
}