package core

import "testing"

// --------------------------------------------------
// Window Tests (generated by ClaudeCode)
// --------------------------------------------------

func TestWindow_SetCursorLine(t *testing.T) {
	t.Run("clamps cursor below zero", func(t *testing.T) {
		buf := NewBufferBuilder().
			WithLines([]string{"line 1", "line 2", "line 3"}).
			Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			Build()

		win.SetCursorLine(-5)

		if win.Cursor.Line != 0 {
			t.Errorf("expected cursor at line 0, got %d", win.Cursor.Line)
		}
	})

	t.Run("clamps cursor past end", func(t *testing.T) {
		buf := NewBufferBuilder().
			WithLines([]string{"line 1", "line 2", "line 3"}).
			Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			Build()

		win.SetCursorLine(999)

		if win.Cursor.Line != 2 { // 3 lines, max index is 2
			t.Errorf("expected cursor at line 2, got %d", win.Cursor.Line)
		}
	})

	t.Run("allows valid position", func(t *testing.T) {
		buf := NewBufferBuilder().
			WithLines([]string{"line 1", "line 2", "line 3"}).
			Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			Build()

		win.SetCursorLine(1)

		if win.Cursor.Line != 1 {
			t.Errorf("expected cursor at line 1, got %d", win.Cursor.Line)
		}
	})

	t.Run("handles empty buffer", func(t *testing.T) {
		buf := NewBufferBuilder().Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			Build()

		win.SetCursorLine(5)

		if win.Cursor.Line != 0 {
			t.Errorf("expected cursor at line 0 for empty buffer, got %d", win.Cursor.Line)
		}
	})
}

func TestWindow_SetCursorCol(t *testing.T) {
	t.Run("clamps to line length", func(t *testing.T) {
		buf := NewBufferBuilder().
			WithLines([]string{"hello"}).
			Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			Build()

		win.SetCursorCol(999)

		// "hello" is 5 chars, max col should be 5 (after last char for insert mode)
		if win.Cursor.Col > 5 {
			t.Errorf("expected cursor col <= 5, got %d", win.Cursor.Col)
		}
	})

	t.Run("clamps below zero", func(t *testing.T) {
		buf := NewBufferBuilder().
			WithLines([]string{"hello"}).
			Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			Build()

		win.SetCursorCol(-10)

		if win.Cursor.Col != 0 {
			t.Errorf("expected cursor col 0, got %d", win.Cursor.Col)
		}
	})

	t.Run("handles empty line", func(t *testing.T) {
		buf := NewBufferBuilder().
			WithLines([]string{""}).
			Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			Build()

		win.SetCursorCol(5)

		if win.Cursor.Col != 0 {
			t.Errorf("expected cursor at col 0 on empty line, got %d", win.Cursor.Col)
		}
	})

	t.Run("allows cursor at end of line", func(t *testing.T) {
		buf := NewBufferBuilder().
			WithLines([]string{"hello"}).
			Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			Build()

		win.SetCursorCol(5) // After last char

		if win.Cursor.Col != 5 {
			t.Errorf("expected cursor at col 5, got %d", win.Cursor.Col)
		}
	})
}

func TestWindow_AdjustScroll(t *testing.T) {
	t.Run("scrolls down when cursor goes below viewport", func(t *testing.T) {
		// Create buffer with many lines
		lines := make([]string, 100)
		for i := range lines {
			lines[i] = "line"
		}
		buf := NewBufferBuilder().WithLines(lines).Build()

		win := NewWindowBuilder().
			WithBuffer(&buf).
			WithHeight(24).
			Build()

		// Start at top
		win.SetCursorLine(0)
		win.AdjustScroll()
		initialScroll := win.ScrollY

		// Move cursor way down
		win.SetCursorLine(50)
		win.AdjustScroll()

		// Scroll should have increased
		if win.ScrollY <= initialScroll {
			t.Errorf("expected scroll to increase, was %d, now %d", initialScroll, win.ScrollY)
		}

		// Cursor should be visible
		viewport := win.ViewportHeight()
		if win.Cursor.Line < win.ScrollY || win.Cursor.Line >= win.ScrollY+viewport {
			t.Errorf("cursor at %d not visible in scroll range [%d, %d)",
				win.Cursor.Line, win.ScrollY, win.ScrollY+viewport)
		}
	})

	t.Run("scrolls up when cursor goes above viewport", func(t *testing.T) {
		lines := make([]string, 100)
		for i := range lines {
			lines[i] = "line"
		}
		buf := NewBufferBuilder().WithLines(lines).Build()

		win := NewWindowBuilder().
			WithBuffer(&buf).
			WithHeight(24).
			Build()

		// Start at bottom
		win.SetCursorLine(80)
		win.AdjustScroll()
		initialScroll := win.ScrollY

		// Move cursor to top
		win.SetCursorLine(5)
		win.AdjustScroll()

		// Scroll should have decreased
		if win.ScrollY >= initialScroll {
			t.Errorf("expected scroll to decrease, was %d, now %d", initialScroll, win.ScrollY)
		}

		// Cursor should be visible
		viewport := win.ViewportHeight()
		if win.Cursor.Line < win.ScrollY || win.Cursor.Line >= win.ScrollY+viewport {
			t.Errorf("cursor at %d not visible in scroll range [%d, %d)",
				win.Cursor.Line, win.ScrollY, win.ScrollY+viewport)
		}
	})

	t.Run("respects scrolloff margin", func(t *testing.T) {
		lines := make([]string, 100)
		for i := range lines {
			lines[i] = "line"
		}
		buf := NewBufferBuilder().WithLines(lines).Build()

		win := NewWindowBuilder().
			WithBuffer(&buf).
			WithHeight(24).
			Build()

		// Set scrolloff to 5
		opts := win.Options
		opts.ScrollOff = 5
		win.SetOptions(opts)

		// Move to line 20 and adjust
		win.SetCursorLine(20)
		win.AdjustScroll()

		viewport := win.ViewportHeight()
		distFromTop := win.Cursor.Line - win.ScrollY
		distFromBottom := (win.ScrollY + viewport - 1) - win.Cursor.Line

		// At least one should respect scrolloff
		if distFromTop < opts.ScrollOff && distFromBottom < opts.ScrollOff {
			t.Errorf("scrolloff %d not respected: top=%d, bottom=%d",
				opts.ScrollOff, distFromTop, distFromBottom)
		}
	})

	t.Run("handles scrolloff larger than half viewport", func(t *testing.T) {
		lines := make([]string, 100)
		for i := range lines {
			lines[i] = "line"
		}
		buf := NewBufferBuilder().WithLines(lines).Build()

		win := NewWindowBuilder().
			WithBuffer(&buf).
			WithHeight(24).
			Build()

		// Set scrolloff larger than half viewport
		opts := win.Options
		opts.ScrollOff = 999
		win.SetOptions(opts)

		win.SetCursorLine(50)
		win.AdjustScroll()

		// Should not panic or error
		viewport := win.ViewportHeight()
		if win.Cursor.Line < win.ScrollY || win.Cursor.Line >= win.ScrollY+viewport {
			t.Error("cursor should still be visible with large scrolloff")
		}
	})

	t.Run("handles small viewport", func(t *testing.T) {
		lines := make([]string, 100)
		for i := range lines {
			lines[i] = "line"
		}
		buf := NewBufferBuilder().WithLines(lines).Build()

		win := NewWindowBuilder().
			WithBuffer(&buf).
			WithHeight(5). // Very small
			Build()

		win.SetCursorLine(50)
		win.AdjustScroll()

		// Should not panic
		viewport := win.ViewportHeight()
		if viewport > 0 && (win.Cursor.Line < win.ScrollY || win.Cursor.Line >= win.ScrollY+viewport) {
			t.Error("cursor should be visible in small viewport")
		}
	})

	t.Run("scrolls right when cursor moves past visible width", func(t *testing.T) {
		buf := NewBufferBuilder().
			WithLines([]string{"0123456789abcdefghij"}).
			Build()

		win := NewWindowBuilder().
			WithBuffer(&buf).
			WithWidth(12).
			WithHeight(10).
			Build()

		win.SetCursorCol(10)
		win.AdjustScroll()

		if win.ScrollX == 0 {
			t.Fatal("expected horizontal scroll to move right")
		}

		viewport := win.ViewportWidth()
		if win.Cursor.Col < win.ScrollX || win.Cursor.Col >= win.ScrollX+viewport {
			t.Errorf("cursor at %d not visible in scroll range [%d, %d)",
				win.Cursor.Col, win.ScrollX, win.ScrollX+viewport)
		}
	})

	t.Run("scrolls left when cursor moves back into hidden content", func(t *testing.T) {
		buf := NewBufferBuilder().
			WithLines([]string{"0123456789abcdefghij"}).
			Build()

		win := NewWindowBuilder().
			WithBuffer(&buf).
			WithWidth(12).
			WithHeight(10).
			Build()

		win.SetCursorCol(14)
		win.AdjustScroll()
		if win.ScrollX == 0 {
			t.Fatal("expected initial horizontal scroll to move right")
		}

		win.SetCursorCol(2)
		win.AdjustScroll()

		if win.ScrollX != 2 {
			t.Errorf("expected horizontal scroll to follow cursor left, got %d", win.ScrollX)
		}
	})
}

func TestWindow_AdjustScrollHorizontalRuneAware(t *testing.T) {
	tests := []struct {
		name          string
		line          string
		width         int
		cursorCol     int
		initialScroll int
		expected      int
	}{
		{
			name:      "ascii line scrolls using visible columns",
			line:      "0123456789abcdef",
			width:     12,
			cursorCol: 10,
			expected:  4,
		},
		{
			name:      "multibyte rune line uses rune length not bytes",
			line:      "abécdefghij",
			width:     10,
			cursorCol: 10,
			expected:  6,
		},
		{
			name:          "moving left pulls scroll back toward cursor",
			line:          "abécdefghij",
			width:         10,
			cursorCol:     2,
			initialScroll: 6,
			expected:      2,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			buf := NewBufferBuilder().WithLines([]string{tt.line}).Build()
			win := NewWindowBuilder().
				WithBuffer(&buf).
				WithWidth(tt.width).
				WithHeight(10).
				Build()

			win.ScrollX = tt.initialScroll
			win.SetCursorCol(tt.cursorCol)
			win.AdjustScroll()

			if win.ScrollX != tt.expected {
				t.Errorf("ScrollX() = %d, want %d", win.ScrollX, tt.expected)
			}

			viewport := win.ViewportWidth()
			if viewport > 0 && (win.Cursor.Col < win.ScrollX || win.Cursor.Col >= win.ScrollX+viewport) {
				t.Errorf("cursor at %d not visible in scroll range [%d, %d)",
					win.Cursor.Col, win.ScrollX, win.ScrollX+viewport)
			}
		})
	}
}

func TestWindow_ViewportHeight(t *testing.T) {
	t.Run("calculates viewport height correctly", func(t *testing.T) {
		buf := NewBufferBuilder().Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			WithHeight(24).
			Build()

		// Height - 2 (status bar + command bar)
		expected := 22
		if win.ViewportHeight() != expected {
			t.Errorf("expected viewport height %d, got %d", expected, win.ViewportHeight())
		}
	})

	t.Run("handles small window", func(t *testing.T) {
		buf := NewBufferBuilder().Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			WithHeight(3).
			Build()

		// 3 - 2 = 1
		expected := 1
		if win.ViewportHeight() != expected {
			t.Errorf("expected viewport height %d, got %d", expected, win.ViewportHeight())
		}
	})

	t.Run("handles zero height", func(t *testing.T) {
		buf := NewBufferBuilder().Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			WithHeight(0).
			Build()

		// With height 0, viewport is 0 - 2 (status + command bars) = -2
		// This is an edge case that shouldn't occur in practice, but shouldn't panic
		result := win.ViewportHeight()
		expected := -2
		if result != expected {
			t.Errorf("expected viewport height %d for zero height window, got %d", expected, result)
		}
	})
}

func TestWindow_ViewportWidth(t *testing.T) {
	t.Run("subtracts gutter width", func(t *testing.T) {
		buf := NewBufferBuilder().WithLines([]string{"line"}).Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			WithWidth(20).
			Build()

		expected := 15
		if win.ViewportWidth() != expected {
			t.Errorf("expected viewport width %d, got %d", expected, win.ViewportWidth())
		}
	})

	t.Run("returns full width when gutter disabled", func(t *testing.T) {
		buf := NewBufferBuilder().WithLines([]string{"line"}).Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			WithWidth(20).
			WithOptions(WinOptions{Number: false, RelativeNumber: false, GutterSize: 5, ScrollOff: 8}).
			Build()

		if win.ViewportWidth() != 20 {
			t.Errorf("expected viewport width 20, got %d", win.ViewportWidth())
		}
	})
}

func TestWindow_SetOptions(t *testing.T) {
	t.Run("updates options", func(t *testing.T) {
		buf := NewBufferBuilder().Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			Build()

		newOpts := WinOptions{
			Number:         false,
			RelativeNumber: false,
			GutterSize:     10,
			ScrollOff:      3,
		}

		win.SetOptions(newOpts)

		if win.Options.Number != false {
			t.Error("expected Number to be false")
		}
		if win.Options.RelativeNumber != false {
			t.Error("expected RelativeNumber to be false")
		}
		if win.Options.GutterSize != 10 {
			t.Errorf("expected GutterSize 10, got %d", win.Options.GutterSize)
		}
		if win.Options.ScrollOff != 3 {
			t.Errorf("expected ScrollOff 3, got %d", win.Options.ScrollOff)
		}
	})

	t.Run("can toggle individual options", func(t *testing.T) {
		buf := NewBufferBuilder().Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			Build()

		// Get current options
		opts := win.Options
		originalNumber := opts.Number

		// Toggle number
		opts.Number = !opts.Number
		win.SetOptions(opts)

		if win.Options.Number == originalNumber {
			t.Error("Number option should have toggled")
		}
	})
}

func TestWindow_SetAnchor(t *testing.T) {
	t.Run("sets anchor line", func(t *testing.T) {
		buf := NewBufferBuilder().
			WithLines([]string{"a", "b", "c"}).
			Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			Build()

		win.SetAnchorLine(2)

		if win.Anchor.Line != 2 {
			t.Errorf("expected anchor line 2, got %d", win.Anchor.Line)
		}
	})

	t.Run("sets anchor col", func(t *testing.T) {
		buf := NewBufferBuilder().
			WithLines([]string{"hello world"}).
			Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			Build()

		win.SetAnchorCol(5)

		if win.Anchor.Col != 5 {
			t.Errorf("expected anchor col 5, got %d", win.Anchor.Col)
		}
	})
}

func TestWindow_SetDimensions(t *testing.T) {
	t.Run("updates width and height", func(t *testing.T) {
		buf := NewBufferBuilder().Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			Build()

		win.SetDimensions(100, 50)

		if win.Width != 100 {
			t.Errorf("expected width 100, got %d", win.Width)
		}
		if win.Height != 50 {
			t.Errorf("expected height 50, got %d", win.Height)
		}
	})
}

func TestWindowBuilder(t *testing.T) {
	t.Run("builds with defaults", func(t *testing.T) {
		buf := NewBufferBuilder().Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			Build()

		// Should have default options
		if win.Options.Number != true {
			t.Error("expected default Number to be true")
		}
		if win.Options.RelativeNumber != true {
			t.Error("expected default RelativeNumber to be true")
		}
		if win.Options.ScrollOff != 8 {
			t.Errorf("expected default ScrollOff 8, got %d", win.Options.ScrollOff)
		}
		if win.Options.GutterSize != 5 {
			t.Errorf("expected default GutterSize 5, got %d", win.Options.GutterSize)
		}
	})

	t.Run("builds with custom cursor position", func(t *testing.T) {
		buf := NewBufferBuilder().
			WithLines([]string{"a", "b", "c"}).
			Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			WithCursorPos(2, 0).
			Build()

		if win.Cursor.Line != 2 {
			t.Errorf("expected cursor line 2, got %d", win.Cursor.Line)
		}
		if win.Cursor.Col != 0 {
			t.Errorf("expected cursor col 0, got %d", win.Cursor.Col)
		}
	})

	t.Run("builds with custom dimensions", func(t *testing.T) {
		buf := NewBufferBuilder().Build()
		win := NewWindowBuilder().
			WithBuffer(&buf).
			WithDimensions(120, 40).
			Build()

		if win.Width != 120 {
			t.Errorf("expected width 120, got %d", win.Width)
		}
		if win.Height != 40 {
			t.Errorf("expected height 40, got %d", win.Height)
		}
	})

	t.Run("assigns unique IDs", func(t *testing.T) {
		buf := NewBufferBuilder().Build()
		win1 := NewWindowBuilder().WithBuffer(&buf).Build()
		win2 := NewWindowBuilder().WithBuffer(&buf).Build()

		if win1.Id == win2.Id {
			t.Errorf("expected unique IDs, both were %d", win1.Id)
		}
	})
}