package buildstep

import (
	"context"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"git.novox.be/novox/mesh-sdk/go/forgekey"
)

// Issue 890 C1 (ADR 0536 §2): a fetch through a bare mirror names the mirror in .git/objects/info/alternates, a
// plain file, and never links it.
func TestFetchCommitWithMirrorWritesAlternates(t *testing.T) {
	mirror := t.TempDir()
	ws := t.TempDir()
	f := &fakeGit{}
	// the fake's init does not create .git; make the objects directory as git init would.
	if err := os.MkdirAll(filepath.Join(ws, ".git", "objects", "info"), 0o755); err != nil {
		t.Fatal(err)
	}
	err := FetchCommit(context.Background(), f.run, ws, "ssh://mesh-forge/novox/mesh-sdk.git", sha, "", WithMirror(mirror))
	if err != nil {
		t.Fatal(err)
	}
	p := filepath.Join(ws, ".git", "objects", "info", "alternates")
	b, err := os.ReadFile(p)
	if err != nil {
		t.Fatal(err)
	}
	if got, want := strings.TrimSpace(string(b)), filepath.Join(mirror, "objects"); got != want {
		t.Errorf("alternates %q, want %q", got, want)
	}
	if fi, err := os.Lstat(p); err != nil || !fi.Mode().IsRegular() {
		t.Errorf("alternates is not a plain file: %v %v", fi, err)
	}
	// the alternates exist before the fetch runs
	if len(f.calls) < 3 || !strings.Contains(f.calls[2], "fetch") {
		t.Errorf("calls %v", f.calls)
	}
}

func TestWithMirrorRefusesARelativeOrMissingMirror(t *testing.T) {
	for _, m := range []string{"rel/mirror", filepath.Join(t.TempDir(), "absent")} {
		f := &fakeGit{}
		err := FetchCommit(context.Background(), f.run, t.TempDir(), "ssh://mesh-forge/novox/x.git", sha, "", WithMirror(m))
		if err == nil || len(f.calls) != 0 {
			t.Errorf("mirror %q: err %v, calls %v", m, err, f.calls)
		}
	}
}

func TestUpdateMirrorInitsBareThenFetches(t *testing.T) {
	mirror := filepath.Join(t.TempDir(), "mirror.git")
	f := &fakeGit{}
	if err := UpdateMirror(context.Background(), f.run, mirror, "ssh://mesh-forge/novox/x.git", sha, ""); err != nil {
		t.Fatal(err)
	}
	pm := "git -c credential.helper= -C " + mirror + " "
	want := []string{
		"git -c credential.helper= init -q --bare " + mirror,
		pm + "remote add origin ssh://mesh-forge/novox/x.git",
		pm + "fetch --no-tags origin " + sha,
		pm + "cat-file -e " + sha + "^{commit}",
	}
	if strings.Join(f.calls, "\n") != strings.Join(want, "\n") {
		t.Errorf("commands:\n%s\nwant:\n%s", strings.Join(f.calls, "\n"), strings.Join(want, "\n"))
	}
}

func TestUpdateMirrorKeepsAnExistingMirrorAndFallsBackToTheRef(t *testing.T) {
	mirror := t.TempDir() // exists: no init
	if err := os.WriteFile(filepath.Join(mirror, "HEAD"), []byte("ref: refs/heads/main\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	f := &fakeGit{}
	f.rule = func(args string) (r forgekey.Ran) {
		if strings.HasSuffix(args, "origin "+sha) {
			r.Status = 1
			r.Stderr = "not our ref"
		}
		return
	}
	if err := UpdateMirror(context.Background(), f.run, mirror, "ssh://mesh-forge/novox/x.git", sha, "refs/pull/3/head"); err != nil {
		t.Fatal(err)
	}
	all := strings.Join(f.calls, "\n")
	if strings.Contains(all, "init") || strings.Contains(all, "remote add") || !strings.Contains(all, "fetch --no-tags origin refs/pull/3/head") {
		t.Errorf("commands:\n%s", all)
	}
}

func TestUpdateMirrorRefusesBeforeRunning(t *testing.T) {
	f := &fakeGit{}
	for _, c := range []struct{ remote, commit string }{
		{"https://x/y.git", sha}, {"ssh://u@h/o/r.git", sha}, {"ssh://h/o/r.git", "abc"},
	} {
		if err := UpdateMirror(context.Background(), f.run, t.TempDir(), c.remote, c.commit, ""); err == nil {
			t.Errorf("%v accepted", c)
		}
	}
	if len(f.calls) != 0 {
		t.Errorf("ran %v", f.calls)
	}
}