package editor

import (
	"testing"

	"pad/internal/ui"
)

// TestCursorPositioning_Basic verifies cursor positioning via GlyphLayout.
func TestCursorPositioning_Basic(t *testing.T) {
TheState = NewState()
TheState.Editor.Buffer = "hello\nworld"

	// Two lines: "hello\n" (bytes 0-5) and "world" (bytes 6-10)
	// Line 0 glyphs at Y=70, Line 1 glyphs at Y=140
	TheState.Editor.GlyphLayout = ui.GlyphLayout{
		ByteOffsets: []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10},
		X:           []ui.Dp{10, 20, 30, 40, 50, 10, 20, 30, 40, 50, 60},
		Y:           []ui.Dp{70, 70, 70, 70, 70, 70, 140, 140, 140, 140, 140},
		Advance:     []ui.Dp{10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10},
	}

	// Test tapping on first line near X=30 (glyph index 2, byteOffset 2)
	SetCursorFromPoint(25, 70)
	if TheState.Editor.CursorPosition < 0 || TheState.Editor.CursorPosition > len(TheState.Editor.Buffer) {
		t.Errorf("cursor position %d out of bounds after first tap", TheState.Editor.CursorPosition)
	}

	// Test tapping on second line
	SetCursorFromPoint(35, 140)
	if TheState.Editor.CursorPosition < 0 || TheState.Editor.CursorPosition > len(TheState.Editor.Buffer) {
		t.Errorf("cursor position %d out of bounds after second tap", TheState.Editor.CursorPosition)
	}
}

// TestCursorPositioning_EmptyDocument verifies cursor positioning handles empty documents.
func TestCursorPositioning_EmptyDocument(t *testing.T) {
TheState = NewState()
TheState.Editor.Buffer = ""
TheState.Editor.GlyphLayout = ui.GlyphLayout{}

	// Should not panic on empty layout
	SetCursorFromPoint(50, 50)

	if TheState.Editor.CursorPosition != 0 {
		t.Errorf("expected cursor at 0 for empty document, got %d", TheState.Editor.CursorPosition)
	}
}

// TestCursorPositioning_IncompleteLayout verifies cursor positioning handles missing layout slices.
func TestCursorPositioning_IncompleteLayout(t *testing.T) {
TheState = NewState()
TheState.Editor.Buffer = "test"
	// GlyphLayout with ByteOffsets and X but no Advance (partial data)
	TheState.Editor.GlyphLayout = ui.GlyphLayout{
		ByteOffsets: []int{0, 1, 2, 3},
		X:           []ui.Dp{10, 20, 30, 40},
		Y:           []ui.Dp{70, 70, 70, 70},
		// Advance intentionally omitted
	}

	// Should not panic when Advance is missing
	SetCursorFromPoint(25, 70)
}

// TestHandleCursorMove_Bounds verifies cursor movement stays within buffer bounds.
func TestHandleCursorMove_Bounds(t *testing.T) {
TheState = NewState()
TheState.Editor.Buffer = "hello"
TheState.Editor.CursorPosition = 0

	// Move right 3 times
	HandleCursorMove(1)
	HandleCursorMove(1)
	HandleCursorMove(1)
	if TheState.Editor.CursorPosition != 3 {
		t.Errorf("expected cursor at 3, got %d", TheState.Editor.CursorPosition)
	}

	// Move right past end — should clamp to buffer length
	HandleCursorMove(10)
	if TheState.Editor.CursorPosition != len(TheState.Editor.Buffer) {
		t.Errorf("expected cursor at %d (end of buffer), got %d", len(TheState.Editor.Buffer), TheState.Editor.CursorPosition)
	}

	// Move left past start — should clamp to 0
	HandleCursorMove(-100)
	if TheState.Editor.CursorPosition != 0 {
		t.Errorf("expected cursor at 0, got %d", TheState.Editor.CursorPosition)
	}
}