package ui

import (
	"strings"

	"github.com/charmbracelet/lipgloss"
)

type helpEntry struct {
	key  string
	desc string
}

func (m Model) helpEntries() []helpEntry {
	switch m.mode {
	case ModeCreate:
		entries := []helpEntry{
			{"enter", "save"},
			{"esc", "cancel"},
		}
		if !m.creatingProject {
			entries = append([]helpEntry{{"ctrl+e", "editor"}}, entries...)
		}
		return entries
	case ModeSearch:
		return []helpEntry{
			{"enter", "apply"},
			{"esc", "cancel"},
		}
	case ModeProjects:
		return []helpEntry{
			{"j/k", "navigate"},
			{"a-z", "jump"},
			{"enter", "select"},
			{"n", "new project"},
			{"e", "edit"},
			{"Y", "Sync"},
			{"x", "delete"},
			{"X", "force delete"},
			{"esc", "cancel"},
		}
	case ModeEditProject:
		return []helpEntry{
			{"tab/↑↓", "fields"},
			{"enter", "save"},
			{"esc", "cancel"},
		}
	case ModeMoveTicket:
		return []helpEntry{
			{"j/k", "navigate"},
			{"a-z", "jump"},
			{"enter", "move here"},
			{"esc", "cancel"},
		}
	case ModeStatus:
		return []helpEntry{
			{"j/k", "select"},
			{"o/w/d", "jump"},
			{"enter", "apply"},
			{"esc", "cancel"},
		}
	case ModeSync:
		return []helpEntry{
			{"j/k", "select"},
			{"p/u", "jump"},
			{"enter", "run"},
			{"esc", "cancel"},
		}
	case ModeBoard:
		return []helpEntry{
			{"j/k", "navigate"},
			{"a/b/i/d", "jump"},
			{"space", "toggle"},
			{"enter", "apply"},
			{"esc", "cancel"},
		}
	case ModeConfirmDelete:
		return []helpEntry{
			{"y/enter", "confirm"},
			{"esc", "cancel"},
		}
	case ModeTimeManual:
		return []helpEntry{
			{"enter", "save"},
			{"esc", "cancel"},
		}
	case ModeTimeEntries:
		return []helpEntry{
			{"j/k", "navigate"},
			{"e", "edit times"},
			{"x", "delete"},
			{"u/U", "undo/redo"},
			{"esc", "back"},
		}
	case ModeTimeEdit:
		return []helpEntry{
			{"tab/↑↓", "fields"},
			{"enter", "save"},
			{"esc", "cancel"},
		}
	case ModeReport:
		return []helpEntry{
			{"g", "group"},
			{"j/k", "scroll"},
			{"esc", "back"},
		}
	case ModeReportGroup:
		return []helpEntry{
			{"j/k", "select"},
			{"p/s/t/d", "jump"},
			{"enter", "apply"},
			{"esc", "cancel"},
		}
	default:
		return []helpEntry{
			{"j/k", "navigate"},
			{"J/K", "checklist"},
			{"S-↑/↓", "checklist"},
			{"space", "check"},
			{"n", "new"},
			{"e", "edit"},
			{"t/T", "timer/log"},
			{"m", "entries"},
			{"r", "report"},
			{"Y", "Sync"},
			{"u/U", "undo/redo"},
			{"/", "search"},
			{"p", "project"},
			{"P", "move"},
			{"l", "list"},
			{"s", "status"},
			{"x", "delete"},
			{"X", "force delete"},
			{"q", "quit"},
		}
	}
}

func (m Model) helpParts() []string {
	parts := make([]string, 0, len(m.helpEntries()))
	for _, e := range m.helpEntries() {
		parts = append(parts, m.styles.HelpKey.Render(e.key)+" "+m.styles.HelpDesc.Render(e.desc))
	}
	return parts
}

func (m Model) helpSep() string {
	sep := m.styles.HelpSep.String()
	if sep == "" {
		return "  "
	}
	return sep
}

// padHelpCell pads a styled help snippet to cellW visible columns.
func padHelpCell(part string, cellW int) string {
	pad := cellW - lipgloss.Width(part)
	if pad < 0 {
		pad = 0
	}
	return part + strings.Repeat(" ", pad)
}

// tableHelpParts lays out styled help snippets as a fixed-width column grid.
func tableHelpParts(parts []string, width int, sep string) []string {
	if len(parts) == 0 {
		return []string{""}
	}
	if width < 1 {
		width = 1
	}

	cellW := 0
	for _, p := range parts {
		if w := lipgloss.Width(p); w > cellW {
			cellW = w
		}
	}
	if cellW < 1 {
		cellW = 1
	}

	sepW := lipgloss.Width(sep)
	cols := 1
	if cellW <= width {
		cols = (width + sepW) / (cellW + sepW)
		if cols < 1 {
			cols = 1
		}
	}

	var lines []string
	for i := 0; i < len(parts); i += cols {
		end := i + cols
		if end > len(parts) {
			end = len(parts)
		}
		row := parts[i:end]
		cells := make([]string, len(row))
		for j, p := range row {
			// Pad every cell except a lone oversized entry on its own row.
			if len(row) == 1 && lipgloss.Width(p) > width {
				cells[j] = p
			} else {
				cells[j] = padHelpCell(p, cellW)
			}
		}
		lines = append(lines, strings.Join(cells, sep))
	}
	return lines
}

func (m Model) renderFooter() string {
	width := m.width
	if width <= 0 {
		width = 80
	}

	ver := m.styles.Version.Render(m.version)
	verW := lipgloss.Width(ver)
	sep := m.helpSep()
	parts := m.helpParts()

	// Table layout so key/desc columns stay aligned across rows.
	lines := tableHelpParts(parts, width, sep)

	// Place version on the last line to the right when it fits; otherwise
	// put it on an extra right-aligned line.
	last := lines[len(lines)-1]
	gap := width - lipgloss.Width(last) - verW
	if gap >= 1 {
		lines[len(lines)-1] = last + strings.Repeat(" ", gap) + ver
	} else {
		pad := width - verW
		if pad < 0 {
			pad = 0
		}
		lines = append(lines, strings.Repeat(" ", pad)+ver)
	}

	return strings.Join(lines, "\n")
}