package session

import (
	"github.com/charmbracelet/x/ansi"

	"termd/internal/api"
)

// modeState mirrors the DEC private modes we care about. Fields are written
// from the emulator's mode callbacks, which fire synchronously inside
// em.Write while the session mutex is already held — so plain fields, no
// locking of their own.
type modeState struct {
	mouseX10    bool // ?9
	mouseNormal bool // ?1000
	mouseButton bool // ?1002
	mouseAny    bool // ?1003
	sgrExt      bool // ?1006

	appCursorKeys  bool // ?1 DECCKM
	bracketedPaste bool // ?2004

	altScreen     bool
	cursorVisible bool
	title         string
}

func (m *modeState) set(mode ansi.Mode, on bool) {
	switch mode {
	case ansi.ModeMouseX10:
		m.mouseX10 = on
	case ansi.ModeMouseNormal:
		m.mouseNormal = on
	case ansi.ModeMouseButtonEvent:
		m.mouseButton = on
	case ansi.ModeMouseAnyEvent:
		m.mouseAny = on
	case ansi.ModeMouseExtSgr:
		m.sgrExt = on
	case ansi.ModeCursorKeys:
		m.appCursorKeys = on
	case ansi.ModeBracketedPaste:
		m.bracketedPaste = on
	}
}

// mouseMode reports the effective tracking mode — the highest one set, which
// is also the one the emulator's SendMouse picks.
func (m *modeState) mouseMode() string {
	switch {
	case m.mouseAny:
		return "any_event"
	case m.mouseButton:
		return "button_event"
	case m.mouseNormal:
		return "normal"
	case m.mouseX10:
		return "x10"
	default:
		return "off"
	}
}

func (m *modeState) api() api.Modes {
	enc := "default"
	if m.sgrExt {
		enc = "sgr"
	}
	return api.Modes{
		Mouse:          m.mouseMode(),
		MouseEncoding:  enc,
		AppCursorKeys:  m.appCursorKeys,
		BracketedPaste: m.bracketedPaste,
	}
}