package ui

import (
	"strings"
	"testing"

	tea "github.com/charmbracelet/bubbletea"

	"github.com/gmgauthier/gralculator/internal/calc"
)

func TestNewApp(t *testing.T) {
	a := NewApp()
	if a == nil {
		t.Fatal("NewApp returned nil")
	}
	if a.engine == nil {
		t.Error("engine not initialized")
	}
	if a.engine.CurrentBase() != calc.BaseDEC {
		t.Error("default base should be DEC")
	}
}

func TestApp_Update_Quit(t *testing.T) {
	a := NewApp()
	_, cmd := a.Update(tea.KeyMsg{Type: tea.KeyCtrlC})
	if cmd == nil {
		t.Error("expected quit cmd for ctrl+c")
	}
	// Simulate the quit msg? But for now, check it returns quit-like
}

func TestApp_Update_DigitsAndDisplay(t *testing.T) {
	a := NewApp()
	a.width = 80
	a.height = 24

	// Type 1 2 3
	for _, d := range "123" {
		a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{d}})
	}

	view := a.View()
	if !contains(view, "123") {
		t.Errorf("expected 123 in view, got: %s", view)
	}
}

func TestApp_Update_Operators(t *testing.T) {
	a := NewApp()
	a.width = 80

	// 2 + 3 =
	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'2'}})
	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'+'}})
	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'3'}})
	a.Update(tea.KeyMsg{Type: tea.KeyEnter})

	view := a.View()
	if !contains(view, "5") {
		t.Errorf("expected result 5, got: %s", view)
	}
}

func TestApp_Update_Mod(t *testing.T) {
	a := NewApp()
	a.width = 80

	// 23 mod 6
	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'2'}})
	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'3'}})
	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'m'}})
	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'6'}})
	a.Update(tea.KeyMsg{Type: tea.KeyEnter})

	view := a.View()
	if !contains(view, "5") {
		t.Errorf("expected 23 mod 6 =5, got: %s", view)
	}
}

func TestApp_Update_BaseCycleAndCERR(t *testing.T) {
	a := NewApp()
	a.width = 80

	// 1 / 3 = (fraction)
	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'1'}})
	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'/'}})
	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'3'}})
	a.Update(tea.KeyMsg{Type: tea.KeyEnter})

	// Tab should CERR
	a.Update(tea.KeyMsg{Type: tea.KeyTab})

	view := a.View()
	if !contains(view, "CERR") {
		t.Errorf("expected CERR flash on fractional base switch, got: %s", view)
	}
}

func TestApp_Update_HEXEntry(t *testing.T) {
	a := NewApp()
	a.width = 80

	// Tab to HEX
	a.Update(tea.KeyMsg{Type: tea.KeyTab})

	// Type 1 A F (hex entry)
	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'1'}})
	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'a'}})
	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'f'}})

	view := a.View()
	if !contains(view, "1AF") {
		t.Errorf("expected raw HEX entry 1AF in display, got: %s", view)
	}
	if !contains(view, "[HEX]") {
		t.Error("expected HEX base indicator")
	}
}

func TestApp_Update_PressedFlash(t *testing.T) {
	a := NewApp()
	a.width = 80

	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'5'}})

	// After key, flash should be set (we can check internal or view for style, but simple state check)
	if a.flash == "" && a.pressedKey == "" {
		t.Error("expected flash or pressedKey after digit")
	}

	// Simulate time tick clear
	a.Update(clearFlashMsg{which: "key"})
	if a.flash != "" || a.pressedKey != "" {
		t.Error("flash should clear after msg")
	}
}

func TestApp_Update_ClearKeys(t *testing.T) {
	a := NewApp()
	a.width = 80

	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'1'}})
	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'2'}})

	// Backspace as C (clear entry)
	a.Update(tea.KeyMsg{Type: tea.KeyBackspace})
	view := a.View()
	if !contains(view, "0") || contains(view, "12") {
		t.Errorf("backspace/C should clear entry to 0, got: %s", view)
	}

	a.Update(tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'9'}})
	// Del as AC
	a.Update(tea.KeyMsg{Type: tea.KeyDelete})
	if a.engine.CurrentBase() != calc.BaseDEC {
		t.Error("Del/AC should reset base")
	}
}

func contains(s, substr string) bool {
	return strings.Contains(s, substr)
}

// Note: clearFlashMsg is defined in ui.go (same package), so we can send it directly in tests.
// The tick func is also package-private but we test via direct messages where possible.