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

//go:build linux && amd64

package debug

import "testing"

func TestConditionEval(t *testing.T) {
	regs := &Regs{
		RAX: 42,
		RBX: 0,
		RCX: 100,
		RIP: 0x1000,
		RSP: 0x2000,
		R8:  8,
		R15: 15,
	}

	tests := []struct {
		cond Condition
		want bool
	}{
		{Condition{Reg: "rax", Op: "==", Value: 42}, true},
		{Condition{Reg: "rax", Op: "==", Value: 43}, false},
		{Condition{Reg: "rax", Op: "!=", Value: 43}, true},
		{Condition{Reg: "rax", Op: "!=", Value: 42}, false},
		{Condition{Reg: "rax", Op: "<", Value: 50}, true},
		{Condition{Reg: "rax", Op: "<", Value: 40}, false},
		{Condition{Reg: "rax", Op: ">", Value: 40}, true},
		{Condition{Reg: "rax", Op: ">", Value: 50}, false},
		{Condition{Reg: "rax", Op: "<=", Value: 42}, true},
		{Condition{Reg: "rax", Op: ">=", Value: 42}, true},
		{Condition{Reg: "rbx", Op: "==", Value: 0}, true},
		{Condition{Reg: "rcx", Op: ">", Value: 50}, true},
		{Condition{Reg: "rip", Op: "==", Value: 0x1000}, true},
		{Condition{Reg: "rsp", Op: ">", Value: 0x1000}, true},
		{Condition{Reg: "r8", Op: "==", Value: 8}, true},
		{Condition{Reg: "r15", Op: "==", Value: 15}, true},
		{Condition{Reg: "eax", Op: "==", Value: 42}, true},    // 32-bit alias
		{Condition{Reg: "ax", Op: "==", Value: 42}, true},     // 16-bit alias
		{Condition{Reg: "unknown", Op: "==", Value: 0}, true}, // unknown reg → don't block
		{Condition{Reg: "rax", Op: "??", Value: 0}, true},     // unknown op → don't block
	}

	for _, tt := range tests {
		got := tt.cond.Eval(regs)
		if got != tt.want {
			t.Errorf("Condition{%q %q %d}.Eval() = %v, want %v",
				tt.cond.Reg, tt.cond.Op, tt.cond.Value, got, tt.want)
		}
	}
}

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 TestDecodeRflags(t *testing.T) {
	tests := []struct {
		flags uint64
		want  string
	}{
		{0x202, "IF"},                   // only IF set (bit 9)
		{0x246, "PF ZF IF"},             // PF(2) + ZF(6) + IF(9)
		{0x001, "CF"},                   // carry flag
		{0x080, "SF"},                   // sign flag
		{0x800, "OF"},                   // overflow flag
		{0x000, "none"},                 // no flags
		{0x202 | 0x001, "CF IF"},        // CF + IF
		{0x3F7, "CF PF AF ZF SF TF IF"}, // all arithmetic flags
	}

	for _, tt := range tests {
		got := decodeRflags(tt.flags)
		if got != tt.want {
			t.Errorf("decodeRflags(%#x) = %q, want %q", tt.flags, 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)
		}
	}
}