// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: BSD-3-Clause

//go:build linux

package debug

// Architecture-neutral tests: label and line tables, and the breakpoint
// manager against the mock tracer.  These do not launch a debuggee, so they
// build on every supported linux architecture.

import (
	"strings"
	"testing"
)

func TestLineAt(t *testing.T) {
	lines := []SourceLine{
		{Offset: 0, Line: 5},
		{Offset: 5, Line: 6},
		{Offset: 10, Line: 7},
		{Offset: 15, Line: 8},
	}

	tests := []struct {
		offset int
		want   int
	}{
		{0, 5},
		{1, 5},
		{4, 5},
		{5, 6},
		{7, 6},
		{10, 7},
		{12, 7},
		{15, 8},
		{20, 8},
	}

	for _, tt := range tests {
		got := lineAt(lines, tt.offset)
		if got != tt.want {
			t.Errorf("lineAt(lines, %d) = %d, want %d", tt.offset, got, tt.want)
		}
	}

	// Empty table.
	if lineAt(nil, 5) != 0 {
		t.Error("lineAt(nil, 5) should return 0")
	}
}

func TestOffsetForLine(t *testing.T) {
	lines := []SourceLine{
		{Offset: 0, Line: 5},
		{Offset: 5, Line: 6},
		{Offset: 10, Line: 7},
	}

	tests := []struct {
		line int
		want int
	}{
		{5, 0},
		{6, 5},
		{7, 10},
		{99, -1}, // not found
		{0, -1},  // not found
	}

	for _, tt := range tests {
		got := offsetForLine(lines, tt.line)
		if got != tt.want {
			t.Errorf("offsetForLine(lines, %d) = %d, want %d", tt.line, got, tt.want)
		}
	}
}

func TestNearestLabel(t *testing.T) {
	labels := []Label{
		{Name: "start", Offset: 0},
		{Name: "loop", Offset: 10},
		{Name: "done", Offset: 20},
	}

	tests := []struct {
		offset int
		want   string
	}{
		{0, "start"},
		{5, "start"},
		{10, "loop"},
		{15, "loop"},
		{20, "done"},
		{25, "done"},
	}

	for _, tt := range tests {
		got := nearestLabel(labels, tt.offset)
		if got != tt.want {
			t.Errorf("nearestLabel(labels, %d) = %q, want %q", tt.offset, got, tt.want)
		}
	}
}

func TestBreakpointsSetAndClear(t *testing.T) {
	tr := newMockTracer()
	bm := NewBreakpoints(tr)

	// Set a breakpoint at address 0x1000.
	bp, err := bm.Set(0x1000, "test")
	if err != nil {
		t.Fatalf("Set: %v", err)
	}
	if !bp.Enabled {
		t.Error("breakpoint not enabled")
	}
	if bp.Label != "test" {
		t.Errorf("label = %q, want test", bp.Label)
	}

	// Verify Peek was called.
	if len(tr.peeks) != 1 || tr.peeks[0] != 0x1000 {
		t.Errorf("peeks = %v, want [0x1000]", tr.peeks)
	}

	// Verify Poke wrote the breakpoint instruction's bytes.
	if len(tr.pokes) != 1 || tr.pokes[0].addr != 0x1000 {
		t.Errorf("pokes = %v", tr.pokes)
	}
	if got := tr.pokes[0].val & breakpointMask(); got != breakpointWord(breakpointInsn) {
		t.Errorf("patched bytes %#x, want %#x", got, breakpointWord(breakpointInsn))
	}

	// At should find it.
	if bm.At(0x1000) == nil {
		t.Error("At(0x1000) returned nil")
	}

	// All should return it.
	all := bm.All()
	if len(all) != 1 {
		t.Errorf("All() = %d breakpoints, want 1", len(all))
	}

	// Clear it.
	if err := bm.Clear(0x1000); err != nil {
		t.Fatalf("Clear: %v", err)
	}
	if bm.At(0x1000) != nil {
		t.Error("At(0x1000) after Clear should be nil")
	}
}

// TestBreakpointRestoreWidth proves the restore path writes back every
// byte of the breakpoint instruction's width, not just the first byte: on
// arm64, riscv64 and loong64 the instruction is four bytes, and restoring
// one byte would leave three bytes of the trap instruction in place.
func TestBreakpointRestoreWidth(t *testing.T) {
	tr := newMockTracer()
	bm := NewBreakpoints(tr)
	tr.mem[0x3000] = 0x11
	tr.mem[0x3001] = 0x22
	tr.mem[0x3002] = 0x33
	tr.mem[0x3003] = 0x44

	if _, err := bm.Set(0x3000, "width"); err != nil {
		t.Fatalf("Set: %v", err)
	}
	for i, b := range breakpointInsn {
		if tr.mem[0x3000+uint64(i)] != b {
			t.Fatalf("byte %d after Set = %#x, want the breakpoint byte %#x", i, tr.mem[0x3000+uint64(i)], b)
		}
	}
	if len(bm.At(0x3000).Orig) != len(breakpointInsn) {
		t.Fatalf("Orig holds %d bytes, want %d", len(bm.At(0x3000).Orig), len(breakpointInsn))
	}

	if err := bm.Clear(0x3000); err != nil {
		t.Fatalf("Clear: %v", err)
	}
	want := []byte{0x11, 0x22, 0x33, 0x44}
	for i, b := range want {
		if tr.mem[0x3000+uint64(i)] != b {
			t.Errorf("byte %d after Clear = %#x, want %#x (restore must cover the full instruction width)", i, tr.mem[0x3000+uint64(i)], b)
		}
	}
}

func TestBreakpointsSetWithCond(t *testing.T) {
	tr := newMockTracer()
	bm := NewBreakpoints(tr)

	cond := &Condition{Reg: "rax", Op: "==", Value: 42}
	bp, err := bm.SetWithCond(0x2000, "cond_test", cond)
	if err != nil {
		t.Fatalf("SetWithCond: %v", err)
	}
	if bp.Cond == nil || bp.Cond.Value != 42 {
		t.Error("condition not set")
	}

	// Re-setting the same address should update the condition.
	cond2 := &Condition{Reg: "rbx", Op: "<", Value: 100}
	bp2, err := bm.SetWithCond(0x2000, "cond_test2", cond2)
	if err != nil {
		t.Fatalf("SetWithCond (update): %v", err)
	}
	if bp2.Cond.Value != 100 {
		t.Error("condition not updated")
	}
	// Should have only 1 Peek (first Set), second is update (no Peek needed).
	if len(tr.peeks) != 1 {
		t.Errorf("expected 1 Peek, got %d", len(tr.peeks))
	}
}

func TestBreakpointsClearAll(t *testing.T) {
	tr := newMockTracer()
	bm := NewBreakpoints(tr)

	bm.Set(0x1000, "a")
	bm.Set(0x2000, "b")
	bm.Set(0x3000, "c")

	if len(bm.All()) != 3 {
		t.Fatalf("expected 3 breakpoints, got %d", len(bm.All()))
	}

	bm.ClearAll()
	if len(bm.All()) != 0 {
		t.Errorf("ClearAll: expected 0 breakpoints, got %d", len(bm.All()))
	}
}

func TestBreakpointInfo(t *testing.T) {
	tr := newMockTracer()
	bm := NewBreakpoints(tr)
	bm.Set(0x4000, "info_test")

	info := bm.Info()
	if info == "" {
		t.Error("Info returned empty string")
	}
	if !strings.Contains(info, "info_test") {
		t.Errorf("Info %q does not contain label", info)
	}
}

// TestConditionString covers the display of all three condition forms.
func TestConditionString(t *testing.T) {
	tests := []struct {
		cond Condition
		want string
	}{
		{Condition{Reg: "rax", Op: "==", Value: 42}, "rax == 0x2a"},
		{Condition{Reg: "rax", Op: "!=", Reg2: "rbx"}, "rax != rbx"},
		{Condition{Reg: "rax", Op: "<", MemAddr: 0x5000}, "rax < *0x5000"},
	}
	for _, tt := range tests {
		if got := tt.cond.String(); got != tt.want {
			t.Errorf("Condition.String() = %q, want %q", got, tt.want)
		}
	}
}