package ui

import (
	"strings"

	"github.com/gdamore/tcell/v2"
	"github.com/rivo/tview"
)

// helpItem is one line of the key reference: the keys and what they do.
type helpItem struct{ keys, desc string }

// helpSection is a titled group of items, with an optional note above them.
type helpSection struct {
	title string
	note  string
	items []helpItem
}

var helpSections = []helpSection{
	{title: "Global", items: []helpItem{
		{"F1-F7", "switch view (also from the release and episode lists)"},
		{"Tab, Shift+Tab", "switch panel within a view"},
		{"F9", "this help (works everywhere, also while typing)"},
		{"Ctrl+C", "quit"},
		{"Esc", "close a dialog / go back"},
	}},
	{title: "Movies and Series", items: []helpItem{
		{"/", "focus the search box"},
		{"Enter, a", "add the selected title (dialog: ↑↓ move, ←→ change a dropdown, Space toggles, Enter/Space opens a list)"},
		{"i", "interactive release search (library titles)"},
	}},
	{title: "Library", items: []helpItem{
		{"Tab", "switch between the movies and series lists"},
		{"f", "cycle the status filter (all, missing, downloaded, monitored, unmonitored); every list has its own filters"},
		{"F", "filter by file properties: quality, codec (x265, x264, AV1), HDR / DV / SDR, audio (Atmos, TrueHD, DTS, DD+ ...), language. Changes apply live behind the dialog, also while you move through an open list; Esc undoes them. Options that would leave no results are not offered. Series files are read on demand."},
		{"/", "text filter for the focused list only; each list keeps its own text (Enter or Esc returns to the list)"},
		{"t", "toggle monitored"},
		{"d", "remove from the library (files are kept unless you tick \"Delete files\")"},
		{"s", "automatic search (series: all missing, asks first)"},
		{"i, Enter", "movie: release search; series: seasons and episodes"},
		{"r", "reload"},
	}},
	{title: "Calendar (F5)", items: []helpItem{
		{"[  ]", "move the two-week window back / forward by a week"},
		{"t", "back to today"},
		{"u", "include unmonitored items"},
		{"Enter, i", "release search for the selected movie / episode"},
		{"s", "automatic search"},
		{"r", "reload"},
	}},
	{title: "Seasons and episodes", items: []helpItem{
		{"Enter", "season: expand / collapse; episode: release search"},
		{"i, s, t", "release search, automatic search, toggle monitored (on a season they apply to the whole season)"},
	}},
	{title: "Release list", items: []helpItem{
		{"Enter, g", "grab the selected release"},
		{"s", "cycle the sort (best, size, age)"},
		{"f", "hide rejected releases"},
		{"F", "filter by quality, codec, HDR / DV, audio, language (read from the release title, quality and custom formats)"},
	}},
	{title: "Downloads", items: []helpItem{
		{"p", "pause / resume the SABnzbd queue"},
		{"d", "delete the selected job or entry"},
		{"b", "remove from the Radarr/Sonarr queue and blocklist"},
		{"t", "retry a failed download (history)"},
		{"r", "refresh now"},
	}},
	{title: "Config (F6)", note: "Edit the settings of the config file: service addresses and API keys, add-form defaults, refresh interval, posters, theme, notifications.", items: []helpItem{
		{"↑↓", "move through all fields, one below the other, in the sections Radarr, Sonarr, SABnzbd and Interface; ↓ after the last field reaches Save and Revert"},
		{"Tab", "jump between the fields and Save / Revert"},
		{"Space", "toggle a checkbox; press a button"},
		{"Test", "(button below the SABnzbd settings) checks the three services with the values typed in"},
		{"Save, Revert", "(at the bottom) Save writes the file and applies everything at once (the theme at the next start); Revert discards edits"},
	}},
	{title: "Log (F7)", note: "Popups fade away by themselves; everything they said is kept here.", items: []helpItem{
		{"↑↓, PgUp, PgDn", "scroll"},
		{"G", "follow new entries"},
		{"c", "clear the log"},
	}},
}

const helpKeyWidth = 16 // columns for the keys, before the descriptions

// renderHelp lays the key reference out for a text area of the given width:
// descriptions that do not fit wrap under themselves, not under the keys.
func renderHelp(width int) string {
	var b strings.Builder
	descWidth := max(width-2-helpKeyWidth, 20)
	for i, sec := range helpSections {
		if i > 0 {
			b.WriteByte('\n')
		}
		b.WriteString("[yellow]" + sec.title + "[-]\n")
		if sec.note != "" {
			for _, l := range flowWrap(tview.Escape(sec.note), width-2, width-2, 0) {
				b.WriteString("  " + l + "\n")
			}
		}
		for _, it := range sec.items {
			keys := tview.Escape(it.keys)
			pad := strings.Repeat(" ", max(helpKeyWidth-tview.TaggedStringWidth(keys), 1))
			lines := flowWrap(tview.Escape(it.desc), descWidth, descWidth, 0)
			for j, l := range lines {
				if j == 0 {
					b.WriteString("  " + keys + pad + l + "\n")
				} else {
					b.WriteString(strings.Repeat(" ", 2+helpKeyWidth) + l + "\n")
				}
			}
		}
	}
	return b.String()
}

// showHelp opens the key reference together with the connection state.
func (a *App) showHelp() {
	screenW, screenH := 100, 40
	if a.screen != nil {
		screenW, screenH = a.screen.Size()
	}
	width := min(100, screenW-4)
	textWidth := width - 3 // border and a column of air
	text := renderHelp(textWidth) + "\n[yellow]Connections[-]\n"
	for _, l := range strings.Split(strings.TrimRight(a.serviceSummary(), "\n"), "\n") {
		for j, w := range flowWrap(l, textWidth-2, textWidth-2, 0) {
			if j == 0 {
				text += "  " + w + "\n"
			} else {
				text += "    " + w + "\n"
			}
		}
	}

	tv := tview.NewTextView().SetDynamicColors(true).SetScrollable(true).SetWrap(false)
	tv.SetBorder(true).SetTitle(" Help — Esc to close ")
	tv.SetBorderPadding(0, 0, 1, 0)
	tv.SetText(text)
	tv.SetInputCapture(func(ev *tcell.EventKey) *tcell.EventKey {
		if ev.Key() == tcell.KeyEsc {
			a.closeModal()
			return nil
		}
		return ev
	})
	height := min(screenH-2, strings.Count(text, "\n")+2)
	a.openModalHints(tv, width, height, "↑↓ PgUp PgDn scroll · Esc close")
}