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

package asm

import (
	"testing"

	"sourcedock.dev/petrbalvin/gasm-sdk/parser"
)

// TestRISCVFrameSpadjAndLines checks that a framed function records its
// stack-adjustment boundaries and source-line table, the inputs the GOOBJ
// emitter turns into the pcsp/pcfile/pcline tables.
func TestRISCVFrameSpadjAndLines(t *testing.T) {
	f, errs := parser.Parse("frame_riscv64.s", `#include "textflag.h"

TEXT ·framed(SB), NOSPLIT, $16-16
	MOV a+0(FP), X10
	MOV b+8(FP), X11
	ADD X11, X10, X10
	MOV X10, ret+16(FP)
	RET
`)
	if len(errs) > 0 {
		t.Fatalf("parse: %v", errs)
	}
	img, err := AssembleFileRISCV(f)
	if err != nil {
		t.Fatalf("AssembleFileRISCV: %v", err)
	}
	fn := img.Funcs[0]
	if fn.Size != 24 {
		t.Fatalf("size = %d, want 24", fn.Size)
	}

	// autosize = 16 + 8 = 24; the prologue boundary is just past its C.ADDI
	// (SD 4 + C.ADDI 2 = 6), and the RET restores SP just past its C.ADDI
	// (RET starts at 16; C.LDSP 2 + C.ADDI 2 = 20).
	wantSpadj := []SpadjStep{{PC: 6, Value: 24}, {PC: 20, Value: 0}}
	if len(fn.Spadj) != len(wantSpadj) {
		t.Fatalf("spadj = %v, want %v", fn.Spadj, wantSpadj)
	}
	for i := range wantSpadj {
		if fn.Spadj[i] != wantSpadj[i] {
			t.Errorf("spadj[%d] = %v, want %v", i, fn.Spadj[i], wantSpadj[i])
		}
	}

	// One line entry per instruction, in emission order.
	wantLines := []LineEntry{
		{Offset: 8, Line: 4},
		{Offset: 10, Line: 5},
		{Offset: 12, Line: 6},
		{Offset: 14, Line: 7},
		{Offset: 16, Line: 8},
	}
	if len(fn.Lines) != len(wantLines) {
		t.Fatalf("lines = %v, want %v", fn.Lines, wantLines)
	}
	for i := range wantLines {
		if fn.Lines[i] != wantLines[i] {
			t.Errorf("lines[%d] = %v, want %v", i, fn.Lines[i], wantLines[i])
		}
	}
}

// TestRISCVFrameSpadjLargeFrame checks the stack-adjustment boundaries of a
// frame past the imm12 range: the prologue materialises the LR-store address
// and the SP adjustment through X31 (C.LUI + C.ADD + SD, then C.LUI + ADDIW +
// C.ADD), so the SP boundary lands at PC 16, and the RET closes with
// C.LDSP plus the same X31 adjustment, 10 bytes.  Regression: both helpers
// assumed the small-frame prologue and reported 8 and 6.
func TestRISCVFrameSpadjLargeFrame(t *testing.T) {
	f, errs := parser.Parse("bigframe_riscv64.s", `#include "textflag.h"

TEXT ·big(SB), NOSPLIT, $9000-8
	MOV a+0(FP), X10
	RET
`)
	if len(errs) > 0 {
		t.Fatalf("parse: %v", errs)
	}
	img, err := AssembleFileRISCV(f)
	if err != nil {
		t.Fatalf("AssembleFileRISCV: %v", err)
	}
	fn := img.Funcs[0]

	// autosize = 9008.  Prologue: C.LUI X31 + C.ADD X31,SP (4) + SD (4) +
	// C.LUI X31 + ADDIW X31 + C.ADD SP,X31 (8) = 16 bytes to the SP boundary;
	// C.SDSP X1 (2) follows, so the body starts at 18.
	wantSpadj := []SpadjStep{{PC: 16, Value: 9008}, {PC: 36, Value: 0}}
	if len(fn.Spadj) != len(wantSpadj) {
		t.Fatalf("spadj = %v, want %v", fn.Spadj, wantSpadj)
	}
	for i := range wantSpadj {
		if fn.Spadj[i] != wantSpadj[i] {
			t.Errorf("spadj[%d] = %v, want %v", i, fn.Spadj[i], wantSpadj[i])
		}
	}
	// The FP load materialises its 9016-byte offset through X31 as well
	// (8 bytes), then RET's epilogue (C.LDSP + X31 adjust = 10) plus JALR.
	if fn.Size != 18+8+14 {
		t.Errorf("size = %d, want %d", fn.Size, 18+8+14)
	}
}

// TestRISCVRegAliases checks the Go ABI register aliases that the toolchain
// defines: LR is the link register (X1) and TMP is the assembler scratch
// register (X31/T6).
func TestRISCVRegAliases(t *testing.T) {
	for name, want := range map[string]int{
		"X1": 1, "RA": 1, "LR": 1,
		"X31": 31, "T6": 31, "TMP": 31,
		"X2": 2, "SP": 2,
	} {
		if got := riscvRegNum(name); got != want {
			t.Errorf("riscvRegNum(%q) = %d, want %d", name, got, want)
		}
	}
}