package dockerexec

import (
	"context"
	"os"
	"path/filepath"
	"regexp"
	"strconv"
	"strings"
	"testing"
)

// TestR650_RealDockerIsRefusedUnderGoTest is the decoy: a harmless-looking `docker ps` with the
// real PATH must NOT run. The consequence asserted is that Run returns the refusal, naming the
// command — and that nothing was started (ProcessState stays nil).
func TestR650_RealDockerIsRefusedUnderGoTest(t *testing.T) {
	t.Setenv(OptInEnv, "")
	for _, name := range []string{"docker", "docker-compose", "/usr/bin/docker"} {
		cmd := Command(name, "ps", "-a")
		err := cmd.Run()
		if err == nil || !strings.Contains(err.Error(), "R-650") || !strings.Contains(err.Error(), "ps -a") {
			t.Fatalf("%s: want an R-650 refusal naming the command, got %v", name, err)
		}
		if cmd.ProcessState != nil {
			t.Fatalf("%s: a process was started", name)
		}
		c2 := CommandContext(context.Background(), name, "volume", "create", "r650-decoy")
		if _, err := c2.CombinedOutput(); err == nil || !strings.Contains(err.Error(), "volume create r650-decoy") {
			t.Fatalf("%s: CommandContext not refused: %v", name, err)
		}
	}
}

// TestR650_StubOnPathIsAllowed — a test's own fake in t.TempDir() is a seam, not Docker.
func TestR650_StubOnPathIsAllowed(t *testing.T) {
	bin := t.TempDir()
	if err := os.WriteFile(filepath.Join(bin, "docker"), []byte("#!/bin/sh\necho stub:$*\n"), 0o755); err != nil {
		t.Fatal(err)
	}
	t.Setenv("PATH", bin)
	out, err := Command("docker", "ps").CombinedOutput()
	if err != nil || strings.TrimSpace(string(out)) != "stub:ps" {
		t.Fatalf("stub should run: out=%q err=%v", out, err)
	}
}

// TestR650_OptInAndProductionAndNonDockerPassThrough — the guard refuses nothing else.
func TestR650_OptInAndProductionAndNonDockerPassThrough(t *testing.T) {
	t.Setenv(OptInEnv, "1")
	if err := refusal("docker", []string{"ps"}); err != nil {
		t.Fatalf("opt-in must allow: %v", err)
	}
	t.Setenv(OptInEnv, "")
	if err := refusal("du", []string{"-sb", "/"}); err != nil {
		t.Fatalf("a non-docker command must pass: %v", err)
	}
	old := underTest
	underTest = func() bool { return false }
	defer func() { underTest = old }()
	if err := refusal("docker", []string{"ps"}); err != nil {
		t.Fatalf("the production binary must never refuse: %v", err)
	}
	if Command("docker", "ps").Err != nil {
		t.Fatal("production Command carried an error")
	}
}

// TestR650_NoBareDockerExec pins the invariant the package doc states: every production path that
// builds a docker process goes through this package. A new `exec.Command("docker", …)` in
// non-test code fails here, naming the file and line.
func TestR650_NoBareDockerExec(t *testing.T) {
	root := filepath.Join("..", "..")
	bare := regexp.MustCompile(`\bexec\.Command(Context)?\(([^,()]+, )?"docker`)
	var hits []string
	n := 0
	err := filepath.Walk(root, func(p string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if info.IsDir() || !strings.HasSuffix(p, ".go") || strings.HasSuffix(p, "_test.go") {
			return nil
		}
		b, err := os.ReadFile(p)
		if err != nil {
			return err
		}
		n++
		for i, line := range strings.Split(string(b), "\n") {
			if bare.MatchString(line) {
				hits = append(hits, p+":"+strconv.Itoa(i+1)+": "+strings.TrimSpace(line))
			}
		}
		return nil
	})
	if err != nil {
		t.Fatal(err)
	}
	if n < 100 {
		t.Fatalf("scope: only %d Go files walked — the sweep is not looking at the tree", n)
	}
	if len(hits) > 0 {
		t.Fatalf("bare docker exec outside dockerexec (R-650):\n%s", strings.Join(hits, "\n"))
	}
}