// Package theme turns config.Theme (the YAML-facing schema) into concrete
// lipgloss.Style values the TUI renders with.
package theme

import (
	"image/color"
	"os"

	"charm.land/bubbles/v2/help"
	"charm.land/bubbles/v2/list"
	"charm.land/bubbles/v2/textinput"
	"charm.land/lipgloss/v2"
	"github.com/charmbracelet/x/term"

	"git.morlana.online/f.weber/vault-tui/internal/config"
)

// Styles is the materialised set of lipgloss styles and colors the whole
// TUI renders with. Built once at startup from config.Theme plus a
// light/dark decision, and passed down by value (styles are cheap,
// immutable value types) to every screen.
type Styles struct {
	// Raw colors, exposed for the few call sites that need to compose a
	// style lipgloss.Style alone can't express (e.g. list.Styles).
	Bg            color.Color
	Surface       color.Color
	SurfaceRaised color.Color
	Overlay       color.Color
	Text          color.Color
	TextMuted     color.Color
	TextFaint     color.Color
	TextInverted  color.Color
	Border        color.Color
	BorderSubtle  color.Color
	BorderActive  color.Color
	Header        color.Color
	Selection     color.Color
	SelectionBg   color.Color
	Accent        color.Color
	Error         color.Color
	Warning       color.Color
	Success       color.Color
	Info          color.Color
	Muted         color.Color
	Masked        color.Color
	Directory     color.Color
	Leaf          color.Color

	MaskChar string
	Mono     bool // true when colors are suppressed (--no-color / NO_COLOR)

	// Chrome
	HeaderBar   lipgloss.Style
	AppBadge    lipgloss.Style
	Crumb       lipgloss.Style
	CrumbSep    lipgloss.Style
	CrumbActive lipgloss.Style
	Pill        lipgloss.Style
	PillOK      lipgloss.Style
	PillWarn    lipgloss.Style
	PillDanger  lipgloss.Style
	Footer      lipgloss.Style
	StatusBar   lipgloss.Style
	ReadOnly    lipgloss.Style

	// Panels
	Panel       lipgloss.Style
	PanelActive lipgloss.Style
	PanelTitle  lipgloss.Style
	PanelSubtle lipgloss.Style
	SidePanel   lipgloss.Style
	EmptyState  lipgloss.Style

	// Rows / tables
	Row         lipgloss.Style
	RowSelected lipgloss.Style
	RowDim      lipgloss.Style
	Badge       lipgloss.Style
	TableHeader lipgloss.Style
	KeyCell     lipgloss.Style
	ValueCell   lipgloss.Style

	// Text roles
	Title       lipgloss.Style
	Help        lipgloss.Style
	ErrorText   lipgloss.Style
	WarnText    lipgloss.Style
	SuccessText lipgloss.Style
	MaskedText  lipgloss.Style
	DirText     lipgloss.Style
	LeafText    lipgloss.Style
	Selected    lipgloss.Style

	// Overlays
	Modal       lipgloss.Style
	ModalDanger lipgloss.Style
	ModalTitle  lipgloss.Style
	Backdrop    lipgloss.Style

	// Toasts
	ToastInfo    lipgloss.Style
	ToastSuccess lipgloss.Style
	ToastWarn    lipgloss.Style
	ToastError   lipgloss.Style

	// Inputs
	InputFocused lipgloss.Style
	InputBlurred lipgloss.Style

	isDark bool
}

// defaultPalette is the built-in fallback: an adaptive light/dark set for
// every named color config.Theme.Colors can override.
func defaultPalette(dark bool) map[string]string {
	if dark {
		return map[string]string{
			"bg": "#0E1015", "surface": "#151821", "surface_raised": "#1C2130", "overlay": "#20263A",
			"text": "#E4E7F1", "text_muted": "#9AA2B8", "text_faint": "#5B6272", "text_inverted": "#0E1015",
			"border": "#2A3040", "border_subtle": "#1C2130", "border_active": "#A78BFA", "header": "#9BA3C4",
			"selection": "#0E1015", "selection_bg": "#A78BFA", "accent": "#A78BFA",
			"error": "#F87171", "warning": "#FBBF24", "success": "#4ADE80", "info": "#6EC1FF",
			"muted": "#9AA2B8", "masked": "#5B6272", "directory": "#6EC1FF", "leaf": "#E4E7F1",
		}
	}
	return map[string]string{
		"bg": "#FFFFFF", "surface": "#F6F7FB", "surface_raised": "#EDEFF7", "overlay": "#E3E6F3",
		"text": "#1F2430", "text_muted": "#6C7086", "text_faint": "#9AA0AE", "text_inverted": "#FFFFFF",
		"border": "#C9CCD6", "border_subtle": "#DEE1EA", "border_active": "#5B34D6", "header": "#3A3F58",
		"selection": "#FFFFFF", "selection_bg": "#5B34D6", "accent": "#5B34D6",
		"error": "#B3261E", "warning": "#8A6100", "success": "#1B6B3A", "info": "#0B5FA5",
		"muted": "#6C7086", "masked": "#9AA0AE", "directory": "#0B5FA5", "leaf": "#1F2430",
	}
}

// IsDark decides light vs. dark once at startup, synchronously — a
// deliberate simplification versus wiring bubbletea's async
// BackgroundColorMsg round trip, since the terminal's background rarely
// changes mid-session. cfg.Appearance can force it.
func IsDark(cfg config.Theme, appearance string) bool {
	switch appearance {
	case "dark":
		return true
	case "light":
		return false
	default:
		return lipgloss.HasDarkBackground(term.File(os.Stdin), term.File(os.Stdout))
	}
}

// NoColor reports whether ANSI color should be suppressed: the NO_COLOR
// convention (https://no-color.org) or an explicit request.
func NoColor(explicit bool) bool {
	if explicit {
		return true
	}
	_, set := os.LookupEnv("NO_COLOR")
	return set
}

func colorOf(cfg config.Theme, defaults map[string]string, dark bool, key string) color.Color {
	if c, ok := cfg.Colors[key]; ok {
		if dark && c.Dark != "" {
			return lipgloss.Color(c.Dark)
		}
		if !dark && c.Light != "" {
			return lipgloss.Color(c.Light)
		}
	}
	return lipgloss.Color(defaults[key])
}

// Build materialises Styles from cfg and the light/dark decision. When mono
// is true (NO_COLOR / --no-color), every color collapses to the terminal's
// default foreground and hierarchy is carried by weight/reverse instead.
func Build(cfg config.Theme, dark bool, mono bool) *Styles {
	def := defaultPalette(dark)
	c := func(key string) color.Color { return colorOf(cfg, def, dark, key) }

	s := &Styles{isDark: dark, Mono: mono}
	s.Bg, s.Surface, s.SurfaceRaised, s.Overlay = c("bg"), c("surface"), c("surface_raised"), c("overlay")
	s.Text, s.TextMuted, s.TextFaint, s.TextInverted = c("text"), c("text_muted"), c("text_faint"), c("text_inverted")
	s.Border, s.BorderSubtle, s.BorderActive, s.Header = c("border"), c("border_subtle"), c("border_active"), c("header")
	s.Selection, s.SelectionBg, s.Accent = c("selection"), c("selection_bg"), c("accent")
	s.Error, s.Warning, s.Success, s.Info = c("error"), c("warning"), c("success"), c("info")
	s.Muted, s.Masked, s.Directory, s.Leaf = c("muted"), c("masked"), c("directory"), c("leaf")

	s.MaskChar = cfg.MaskChar
	if s.MaskChar == "" {
		s.MaskChar = "•"
	}

	if mono {
		s.flatten()
	}

	border := borderFor(cfg.BorderStyle)
	pillFG := s.TextInverted

	s.HeaderBar = lipgloss.NewStyle().Foreground(s.Text).Background(s.Surface).Padding(0, 1)
	s.AppBadge = lipgloss.NewStyle().Foreground(pillFG).Background(s.Accent).Bold(true).Padding(0, 1)
	s.Crumb = lipgloss.NewStyle().Foreground(s.TextMuted).Background(s.Surface)
	s.CrumbSep = lipgloss.NewStyle().Foreground(s.TextFaint).Background(s.Surface)
	s.CrumbActive = lipgloss.NewStyle().Foreground(s.Text).Background(s.Surface).Bold(true)
	s.Pill = lipgloss.NewStyle().Foreground(s.Text).Background(s.SurfaceRaised).Padding(0, 1)
	s.PillOK = s.Pill.Foreground(pillFG).Background(s.Success)
	s.PillWarn = s.Pill.Foreground(pillFG).Background(s.Warning)
	s.PillDanger = s.Pill.Foreground(pillFG).Background(s.Error)
	s.Footer = lipgloss.NewStyle().Foreground(s.TextMuted).Background(s.Surface).Padding(0, 1)
	s.StatusBar = lipgloss.NewStyle().Foreground(s.TextMuted).Background(s.Surface)
	s.ReadOnly = s.PillWarn.Bold(true)

	s.Panel = lipgloss.NewStyle().Border(border).BorderForeground(s.Border).Padding(0, 1)
	s.PanelActive = s.Panel.BorderForeground(s.BorderActive)
	s.PanelTitle = lipgloss.NewStyle().Foreground(s.Accent).Bold(true)
	s.PanelSubtle = lipgloss.NewStyle().Foreground(s.TextMuted)
	s.SidePanel = lipgloss.NewStyle().Border(border).BorderForeground(s.BorderSubtle).Padding(0, 1)
	s.EmptyState = lipgloss.NewStyle().Foreground(s.TextFaint).Italic(true)

	s.Row = lipgloss.NewStyle().Foreground(s.Text)
	s.RowSelected = lipgloss.NewStyle().Foreground(s.Selection).Background(s.SelectionBg).Bold(true)
	s.RowDim = lipgloss.NewStyle().Foreground(s.TextFaint)
	s.Badge = lipgloss.NewStyle().Foreground(s.TextMuted).Background(s.SurfaceRaised).Padding(0, 1)
	s.TableHeader = lipgloss.NewStyle().Foreground(s.TextMuted).Bold(true)
	s.KeyCell = lipgloss.NewStyle().Foreground(s.Text).Bold(true)
	s.ValueCell = lipgloss.NewStyle().Foreground(s.TextMuted)

	s.Title = lipgloss.NewStyle().Foreground(s.Accent).Bold(true)
	s.Help = lipgloss.NewStyle().Foreground(s.TextMuted)
	s.ErrorText = lipgloss.NewStyle().Foreground(s.Error).Bold(true)
	s.WarnText = lipgloss.NewStyle().Foreground(s.Warning)
	s.SuccessText = lipgloss.NewStyle().Foreground(s.Success)
	s.MaskedText = lipgloss.NewStyle().Foreground(s.Masked)
	s.DirText = lipgloss.NewStyle().Foreground(s.Directory)
	s.LeafText = lipgloss.NewStyle().Foreground(s.Leaf)
	s.Selected = s.RowSelected

	s.Modal = lipgloss.NewStyle().Border(lipgloss.RoundedBorder()).BorderForeground(s.Accent).
		Background(s.Overlay).Foreground(s.Text).Padding(1, 2)
	s.ModalDanger = s.Modal.BorderForeground(s.Error)
	s.ModalTitle = lipgloss.NewStyle().Foreground(s.Accent).Bold(true)
	s.Backdrop = lipgloss.NewStyle().Foreground(s.TextFaint)

	s.ToastInfo = lipgloss.NewStyle().Foreground(pillFG).Background(s.Info).Padding(0, 1)
	s.ToastSuccess = lipgloss.NewStyle().Foreground(pillFG).Background(s.Success).Padding(0, 1)
	s.ToastWarn = lipgloss.NewStyle().Foreground(pillFG).Background(s.Warning).Padding(0, 1)
	s.ToastError = lipgloss.NewStyle().Foreground(pillFG).Background(s.Error).Padding(0, 1)

	s.InputFocused = lipgloss.NewStyle().Foreground(s.Accent)
	s.InputBlurred = lipgloss.NewStyle().Foreground(s.TextMuted)

	return s
}

// flatten drops every color to the terminal's default foreground (mono
// mode). Called before styles are built so every lipgloss.Style below
// inherits plain colors and relies on Bold/Italic/Reverse for hierarchy.
func (s *Styles) flatten() {
	none := lipgloss.Color("")
	*s = Styles{
		isDark: s.isDark, Mono: true, MaskChar: s.MaskChar,
		Bg: none, Surface: none, SurfaceRaised: none, Overlay: none,
		Text: none, TextMuted: none, TextFaint: none, TextInverted: none,
		Border: none, BorderSubtle: none, BorderActive: none, Header: none,
		Selection: none, SelectionBg: none, Accent: none,
		Error: none, Warning: none, Success: none, Info: none,
		Muted: none, Masked: none, Directory: none, Leaf: none,
	}
}

func borderFor(style string) lipgloss.Border {
	switch style {
	case "normal":
		return lipgloss.NormalBorder()
	case "thick":
		return lipgloss.ThickBorder()
	case "double":
		return lipgloss.DoubleBorder()
	case "hidden":
		return lipgloss.HiddenBorder()
	case "ascii":
		return lipgloss.Border{Top: "-", Bottom: "-", Left: "|", Right: "|", TopLeft: "+", TopRight: "+", BottomLeft: "+", BottomRight: "+"}
	default:
		return lipgloss.RoundedBorder()
	}
}

// HelpStyles adapts bubbles/help's palette to the theme.
func (s *Styles) HelpStyles() help.Styles {
	hs := help.DefaultStyles(s.isDark)
	hs.ShortKey = lipgloss.NewStyle().Foreground(s.Accent)
	hs.ShortDesc = lipgloss.NewStyle().Foreground(s.TextMuted)
	hs.ShortSeparator = lipgloss.NewStyle().Foreground(s.TextFaint)
	hs.FullKey = hs.ShortKey
	hs.FullDesc = hs.ShortDesc
	hs.FullSeparator = hs.ShortSeparator
	hs.Ellipsis = lipgloss.NewStyle().Foreground(s.TextFaint)
	return hs
}

// TextInputStyles adapts bubbles/textinput's palette to the theme.
func (s *Styles) TextInputStyles() textinput.Styles {
	ti := textinput.DefaultStyles(s.isDark)
	ti.Focused.Text = lipgloss.NewStyle().Foreground(s.Text)
	ti.Focused.Prompt = lipgloss.NewStyle().Foreground(s.Accent)
	ti.Focused.Placeholder = lipgloss.NewStyle().Foreground(s.TextFaint)
	ti.Blurred.Text = lipgloss.NewStyle().Foreground(s.TextMuted)
	ti.Blurred.Prompt = lipgloss.NewStyle().Foreground(s.TextFaint)
	ti.Blurred.Placeholder = lipgloss.NewStyle().Foreground(s.TextFaint)
	ti.Cursor.Color = s.Accent
	return ti
}

// ListStyles adapts bubbles/list's chrome (filter prompt/cursor, "no
// items", help line) to the theme. The list's per-row rendering is handled
// entirely by our own list.ItemDelegate, not by this.
func (s *Styles) ListStyles() list.Styles {
	ls := list.DefaultStyles(s.isDark)
	ls.Filter = s.TextInputStyles()
	ls.NoItems = s.EmptyState
	ls.StatusEmpty = s.EmptyState
	ls.HelpStyle = s.Help
	ls.StatusBarActiveFilter = lipgloss.NewStyle().Foreground(s.Text)
	ls.StatusBarFilterCount = lipgloss.NewStyle().Foreground(s.TextFaint)
	ls.PaginationStyle = lipgloss.NewStyle().Foreground(s.TextFaint)
	ls.DefaultFilterCharacterMatch = lipgloss.NewStyle().Foreground(s.Accent).Underline(true)
	return ls
}