// ================================================================================== tests for gbld (mwx'2026)
package main

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"
)

func inTempDir(t *testing.T) { // ------------------------------------- run a test in an empty working directory
  t.Helper()
  old, err := os.Getwd()
  if err != nil {
    t.Fatal(err)
  }
  dir := t.TempDir()
  if err := os.Chdir(dir); err != nil {
    t.Fatal(err)
  }
  t.Cleanup(func() { os.Chdir(old) })
}

func write(t *testing.T, name, content string) { // ------------------------------------------ write a test file
  t.Helper()
  if err := os.WriteFile(name, []byte(content), 0644); err != nil {
    t.Fatal(err)
  }
}

func TestGettargetversion(t *testing.T) { // ------------------------------------------- find 'var version = ..'
  inTempDir(t)

  if _, err := gettargetversion(); err == nil {
    t.Error("expected an error when no version is defined")
  }

  write(t, "other.go", "package main\n\n"+`var tbversion = "0.1.0"`+"\n")
  if _, err := gettargetversion(); err == nil {
    t.Error("tbversion must not be taken for the target version")
  }

  write(t, "app.go", "package main\n\n"+`var version = "2.3.0" // release`+"\n")
  v, err := gettargetversion()
  if err != nil {
    t.Fatal(err)
  }
  if v != "2.3.0" {
    t.Errorf("got %q, want 2.3.0 (a trailing comment must not break the match)", v)
  }
}

func TestBumpbuild(t *testing.T) { // ------------------------------------- counter increases, comment survives
  inTempDir(t)

  write(t, "build.go", "package main\n\n"+`var build = "41" // counter`+"\n")
  bumpbuild()

  c, err := os.ReadFile("build.go")
  if err != nil {
    t.Fatal(err)
  }
  want := "package main\n\n" + `var build = "42" // counter` + "\n"
  if string(c) != want {
    t.Errorf("got %q, want %q", string(c), want)
  }

  files, _ := filepath.Glob("tmp/build.go.*") // the backup is what protects the users file
  if len(files) != 1 {
    t.Errorf("expected exactly one backup in tmp/, got %v", files)
  }
}

func TestBackupPruning(t *testing.T) { // ---------------------------------- tmp/ must not grow without bounds
  inTempDir(t)

  write(t, "build.go", "package main\n\n"+`var build = "1"`+"\n")
  for i := 0; i < KEEPBACKUPS+5; i++ { // same second: force distinct names to test the pruning itself
    if err := backup("build.go"); err != nil {
      t.Fatal(err)
    }
    write(t, SF("tmp/build.go.2026010112000%02d", i), "old backup")
    prunebackups("build.go", KEEPBACKUPS)
  }

  files, _ := filepath.Glob("tmp/build.go.*")
  if len(files) > KEEPBACKUPS {
    t.Errorf("got %d backups, want at most %d", len(files), KEEPBACKUPS)
  }
}

func TestBumpbuildKeepsLongLines(t *testing.T) { // -------------- a >64k line must not truncate the file anymore
  inTempDir(t)

  long := strings.Repeat("x", 100*1024)
  write(t, "build.go", "package main\n\n"+`var build = "1"`+"\n\nvar long = \""+long+"\"\n")
  bumpbuild()

  c, err := os.ReadFile("build.go")
  if err != nil {
    t.Fatal(err)
  }
  if !strings.Contains(string(c), `var build = "2"`) {
    t.Error("counter was not increased")
  }
  if !strings.Contains(string(c), long) {
    t.Error("long line was lost - the file got truncated")
  }
}

func TestArtifact(t *testing.T) { // --------------------------------------------- windows artifacts need '.exe'
  if got := artifact("gbld", "1.2.3", "linux", "amd64"); got != "gbld_1.2.3_linux_amd64" {
    t.Errorf("got %q", got)
  }
  if got := artifact("gbld", "1.2.3", "windows", "amd64"); got != "gbld_1.2.3_windows_amd64.exe" {
    t.Errorf("got %q", got)
  }
}

func TestFileExists(t *testing.T) { // --------------------------------- must not panic on unreadable entries
  inTempDir(t)

  write(t, "there.go", "package main\n")
  if !fileExists("there.go") {
    t.Error("existing file not found")
  }
  if fileExists("missing.go") {
    t.Error("missing file reported as existing")
  }
  os.Mkdir("adir", 0755)
  if fileExists("adir") {
    t.Error("a directory is not a file")
  }

  os.Mkdir("locked", 0000) // no permission: os.Stat fails with something other than IsNotExist
  defer os.Chmod("locked", 0755)
  if fileExists("locked/x.go") {
    t.Error("unreadable path reported as existing")
  }
}

func TestUpdateFindSum(t *testing.T) { // ----------------------------------- checksums are read and validated
  good := strings.Repeat("ab", 32) // 32 bytes, as a sha256 has
  body := []byte(good + "  gbld-linux-amd64\n" +
    good + " *gbld-windows-amd64.exe\n" + // binary mode marks the name with '*'
    "zzzz  broken_sum\n")

  sum, err := updateFindSum(body, "gbld-linux-amd64")
  if err != nil {
    t.Fatal(err)
  }
  if hex.EncodeToString(sum) != good {
    t.Errorf("wrong checksum decoded: %x", sum)
  }

  if _, err := updateFindSum(body, "gbld-windows-amd64.exe"); err != nil {
    t.Errorf("the '*' of binary mode belongs to the format, not to the name: %v", err)
  }
  if _, err := updateFindSum(body, "gbld-darwin-arm64"); err == nil {
    t.Error("a missing entry must be an error - never update without a checksum")
  }
  if _, err := updateFindSum(body, "broken_sum"); err == nil {
    t.Error("a malformed checksum must be an error")
  }
  if _, err := updateFindSum([]byte(strings.Repeat("ab", 16)+"  gbld-linux-amd64\n"), "gbld-linux-amd64"); err == nil {
    t.Error("a hash of the wrong length must be an error")
  }
}

func TestUpdateChecksum(t *testing.T) { // ------------------------- the checksum comes out of the release itself
  want := strings.Repeat("cd", 32)
  srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte(want + "  gbld-linux-amd64\n"))
  }))
  defer srv.Close()

  rel := updateRelease{TagName: "v1.2.3", Assets: []updateAsset{
    {Name: "gbld-linux-amd64", URL: srv.URL + "/gbld-linux-amd64"},
    {Name: updateChecksums, URL: srv.URL + "/" + updateChecksums},
  }}

  sum, err := selfUpdate.checksum(rel, "gbld-linux-amd64")
  if err != nil {
    t.Fatal(err)
  }
  if hex.EncodeToString(sum) != want {
    t.Errorf("wrong checksum: %x", sum)
  }

  bare := updateRelease{TagName: "v1.2.3", Assets: rel.Assets[:1]} // no checksums.txt published
  if _, err := selfUpdate.checksum(bare, "gbld-linux-amd64"); err == nil {
    t.Error("a release without checksums must be refused")
  }
}

func TestUpdateDownloadRejectsWrongChecksum(t *testing.T) { // ------ a manipulated download is never installed
  body := []byte("this is not the binary you asked for")
  srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    w.Write(body)
  }))
  defer srv.Close()

  dir := t.TempDir()
  exe := filepath.Join(dir, "gbld")
  a := &updateAsset{Name: "gbld-linux-amd64", Size: int64(len(body)), URL: srv.URL + "/gbld-linux-amd64"}

  _, err := selfUpdate.download(a, exe, 0755, []byte{0xde, 0xad, 0xbe, 0xef})
  if err == nil {
    t.Fatal("a download with a wrong checksum was accepted")
  }
  if !strings.Contains(strings.ToLower(err.Error()), "checksum") {
    t.Errorf("expected a checksum error, got: %v", err)
  }

  left, _ := filepath.Glob(filepath.Join(dir, "*"))
  if len(left) != 0 {
    t.Errorf("the rejected download was left behind: %v", left)
  }

  sum := sha256.Sum256(body) // the same bytes, now with the checksum that fits
  tmp, err := selfUpdate.download(a, exe, 0755, sum[:])
  if err != nil {
    t.Fatalf("a matching checksum was refused: %v", err)
  }
  os.Remove(tmp)
}

func TestUpdateGetStatus(t *testing.T) { // ---------------------------------- http errors must not be swallowed
  srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    http.Error(w, "nope", http.StatusInternalServerError)
  }))
  defer srv.Close()

  ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
  defer cancel()

  if _, err := updateGet(ctx, srv.URL); err == nil {
    t.Error("http 500 was reported as success")
  }
}

func TestUpdateCompare(t *testing.T) { // ------------------- versions are numbers, not strings: 1.21.10 > 1.21.9
  for _, c := range []struct {
    a, b string
    want int
  }{
    {"1.21.10", "1.21.9", 1},
    {"v1.21.0", "1.21.0", 0},
    {"1.21", "1.21.0", 0},
    {"1.21.0-rc1", "1.21.0", -1}, // not finished yet
    {"1.9.0", "1.10.0", -1},
  } {
    if got := updateCompare(c.a, c.b); got != c.want {
      t.Errorf("updateCompare(%q,%q) = %d, want %d", c.a, c.b, got, c.want)
    }
    if got := updateCompare(c.b, c.a); got != -c.want {
      t.Errorf("updateCompare(%q,%q) = %d, want %d", c.b, c.a, got, -c.want)
    }
  }
}

func TestToolbox(t *testing.T) { // ------------------------------------------------ toolbox edge cases
  if got := Shortstr("abcdef", 4); got != "ab.." {
    t.Errorf("Shortstr: got %q", got)
  }
  if got := Shortstr("abcdef", 1); got != ".." { // must not panic
    t.Errorf("Shortstr with a tiny length: got %q", got)
  }
  if got := Dec("!!!not valid!!!"); got != "" { // must not panic
    t.Errorf("Dec of garbage: got %q", got)
  }
  if got := Dec(Enc("secret")); got != "secret" {
    t.Errorf("Enc/Dec roundtrip: got %q", got)
  }

  in := []string{"a", "b", "a", "c"}
  out := RemoveAllMatches(in, "a")
  if strings.Join(out, "") != "bc" {
    t.Errorf("RemoveAllMatches: got %v", out)
  }
  if strings.Join(in, "") != "abac" {
    t.Errorf("RemoveAllMatches modified the callers slice: %v", in)
  }

  if !Checkip("10.0.0.0/8", "10.1.2.3") || Checkip("10.0.0.0/8", "192.168.0.1") {
    t.Error("Checkip cidr")
  }
  if Checkip("10.0.0.0/8", "not an ip") {
    t.Error("Checkip accepted an invalid address")
  }
}

// ========================================================================================================= END