package domain

import (
	"time"

	"github.com/bnema/vev/internal/domain/terminalcap"
)

// MinBarInterval is the minimum supported bar refresh interval.
const MinBarInterval = time.Second

// DefaultWordSeparators matches tmux's practical shell-oriented word boundaries.
const DefaultWordSeparators = " -_@"

// ThemeMode selects how vev derives its color scheme.
type ThemeMode int

const (
	// ThemeAuto follows the attached client's reported color scheme.
	ThemeAuto ThemeMode = iota
	// ThemeDark forces vev's built-in dark palette.
	ThemeDark
	// ThemeLight forces vev's built-in light palette.
	ThemeLight
)

// ConfigEntry preserves one parsed config key/value in file order.
type ConfigEntry struct {
	Key   string
	Value string
}

// SnapshotConfig contains user-configurable snapshot restore settings.
type SnapshotConfig struct {
	RestoreProcesses    []string
	RestoreProcessesSet bool
}

// defaultSnapshotRestoreProcesses is the default allowlist for process restore.
var defaultSnapshotRestoreProcesses = []string{
	"vi", "vim", "nvim", "emacs", "man", "less", "more", "tail", "top", "htop", "btop",
	"claude", "codex", "pi", "opencode",
}

// DefaultSnapshotRestoreProcesses returns a copy of the default process restore allowlist.
func DefaultSnapshotRestoreProcesses() []string {
	return append([]string(nil), defaultSnapshotRestoreProcesses...)
}

// BarConfig contains user-configurable bar right-anchor settings.
type BarConfig struct {
	TopRight    string
	BottomRight string
	Interval    time.Duration
}

// CopyConfig contains copy-mode selection and mouse motion settings.
type CopyConfig struct {
	WordSeparators string
	ReduceMotion   bool
}

// PaletteConfig contains palette placement settings. A false AnchorSet uses the
// adaptive automatic placement.
type PaletteConfig struct {
	Anchor    Anchor
	AnchorSet bool
}

// FloatingConfig contains launch and sizing settings for per-tab floating panes.
type FloatingConfig struct {
	Command string
	Width   int
	Height  int
}

// NavConfig contains directional navigation overflow settings.
type NavConfig struct {
	OverflowTabs     bool
	OverflowSessions bool
}

// TabsConfig contains tab label display settings.
type TabsConfig struct {
	// TerminalTitle includes the focused pane's OSC terminal title in tab
	// labels (top bar and session picker). The process name always shows.
	TerminalTitle bool
}

// EphemeralConfig contains numbered-session lifetime settings.
type EphemeralConfig struct {
	// CloseOnExit removes an ephemeral session once its last attachment ends
	// definitively: a closed client process (Detach{Closed}), or an expired
	// park or suspension. A user detach keeps it.
	CloseOnExit bool
}

// KeyboardConfig contains outer-terminal keyboard settings.
type KeyboardConfig struct {
	// KittyProtocol enables the kitty keyboard protocol on outer terminals
	// that support it, which makes Ctrl+1..9 recent-session switching work.
	KittyProtocol bool
}

// EchoPredictMode selects when a remote attachment shows predicted local echo.
type EchoPredictMode uint8

const (
	// EchoPredictNever disables prediction. It is the zero value, so a
	// client composed without the user's config (virtual terminals, UI
	// drivers) never predicts.
	EchoPredictNever EchoPredictMode = iota
	// EchoPredictAdaptive shows predictions only on a slow or glitchy link.
	EchoPredictAdaptive
	// EchoPredictAlways shows predictions whatever the link latency.
	EchoPredictAlways
)

// EchoConfig contains client-side predictive echo settings.
type EchoConfig struct {
	// Predict selects when remote attachments draw typed characters before
	// the daemon echoes them.
	Predict EchoPredictMode
}

// TerminalConfig contains client-side outer-terminal settings. It is read by
// each client at startup and never applied by the daemon, so a change takes
// effect on the next client process.
type TerminalConfig struct {
	// Colors is the forced color mode when ColorsSet is true. A false
	// ColorsSet (terminal.colors = auto, the default) uses detection.
	Colors    terminalcap.ColorMode
	ColorsSet bool
}

// ScrollbackConfig is vev's per-pane retention policy. The terminal library
// only enforces these application-selected limits. Zero megabytes disables
// history; zero lines removes the additional line ceiling.
type ScrollbackConfig struct {
	Megabytes uint64
	Lines     int
}

const DefaultScrollbackMegabytes uint64 = 50
const DefaultScrollbackLines = 10_000
const MaxScrollbackMegabytes uint64 = 4096
const MaxScrollbackLines = 1_000_000

func DefaultScrollbackConfig() ScrollbackConfig {
	return ScrollbackConfig{Megabytes: DefaultScrollbackMegabytes, Lines: DefaultScrollbackLines}
}

func (c ScrollbackConfig) Valid() bool {
	return c.Megabytes <= MaxScrollbackMegabytes && c.Lines >= 0 && c.Lines <= MaxScrollbackLines
}

// Config is the user-editable vev configuration after parsing. Unknown binding
// keys are preserved here (in BindingEntries, in file order) so the usecase
// layer can decide which actions it understands.
type Config struct {
	WebListen      string
	WebOrigin      string
	Theme          ThemeMode
	ThemePalette   bool
	ThemeAccent    ThemeAccent
	Bar            BarConfig
	BindingEntries []ConfigEntry
	Codes          map[string]string
	Snapshot       SnapshotConfig
	Copy           CopyConfig
	Palette        PaletteConfig
	Floating       FloatingConfig
	Nav            NavConfig
	Tabs           TabsConfig
	Ephemeral      EphemeralConfig
	Keyboard       KeyboardConfig
	Echo           EchoConfig
	Terminal       TerminalConfig
	Scrollback     ScrollbackConfig
}

// Warning describes a non-fatal config problem. Parsers and reloaders should
// warn and continue with defaults rather than aborting startup.
type Warning struct {
	Line int
	Msg  string
}

// Defaults returns vev's default configuration.
func Defaults() Config {
	return Config{
		Theme:        ThemeAuto,
		ThemePalette: true,
		ThemeAccent:  ThemeAccent{Mode: ThemeAccentAuto},
		Bar: BarConfig{
			Interval: 5 * time.Second,
		},
		BindingEntries: []ConfigEntry{},
		Codes:          map[string]string{},
		Snapshot: SnapshotConfig{
			RestoreProcesses: DefaultSnapshotRestoreProcesses(),
		},
		Copy: CopyConfig{
			WordSeparators: DefaultWordSeparators,
		},
		Palette: PaletteConfig{
			Anchor:    AnchorCenter,
			AnchorSet: true,
		},
		Floating: FloatingConfig{
			Width:  80,
			Height: 80,
		},
		Tabs: TabsConfig{
			TerminalTitle: true,
		},
		Ephemeral: EphemeralConfig{
			CloseOnExit: true,
		},
		Keyboard: KeyboardConfig{
			KittyProtocol: true,
		},
		Echo: EchoConfig{
			Predict: EchoPredictAdaptive,
		},
		Scrollback: DefaultScrollbackConfig(),
	}
}