package service

import (
	"context"
	"io"
	"log/slog"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"gitmanager/internal/activity"
	"gitmanager/internal/git"
	"gitmanager/internal/repos"
)

// TestGitActions exercises the mutating commands (commit, discard) on a throwaway
// temp repo — never a real one.
func TestGitActions(t *testing.T) {
	root := t.TempDir()
	repoPath := filepath.Join(root, "r")
	mustMkdir(t, repoPath)
	runGit(t, repoPath, "init", "-b", "main")
	runGit(t, repoPath, "config", "user.email", "t@e.com")
	runGit(t, repoPath, "config", "user.name", "T")
	writeFile(t, filepath.Join(repoPath, "a.txt"), "one\n")
	runGit(t, repoPath, "add", "-A")
	runGit(t, repoPath, "commit", "-m", "init")

	log := slog.New(slog.NewTextHandler(io.Discard, nil))
	g := git.New("git")
	scanner := repos.NewScanner(g, log, []string{root}, 3, nil, time.Minute, false)
	scanner.Refresh(context.Background())
	feed := activity.New(log, 200)
	svc := New(g, scanner.Index, feed, nil, scanner.RefreshRepo)
	ctx := context.Background()

	// Commit a new file, then the repo should be clean in the index.
	writeFile(t, filepath.Join(repoPath, "b.txt"), "two\n")
	if _, err := svc.GitCommit(ctx, activity.ActorUser, repoPath, "add b"); err != nil {
		t.Fatalf("GitCommit: %v", err)
	}
	if st, _ := svc.GetRepo(repoPath); st.Dirty {
		t.Fatalf("expected clean repo after commit, got dirty")
	}

	// Commit with a blank message is rejected.
	if _, err := svc.GitCommit(ctx, activity.ActorUser, repoPath, "   "); err == nil {
		t.Fatalf("expected error committing with blank message")
	}

	// Modify a tracked file, then discard resets it. (We check the file itself
	// rather than index dirtiness, since the index only updates on a refresh.)
	writeFile(t, filepath.Join(repoPath, "a.txt"), "CHANGED\n")
	if _, err := svc.GitDiscard(ctx, activity.ActorUser, repoPath); err != nil {
		t.Fatalf("GitDiscard: %v", err)
	}
	if st, _ := svc.GetRepo(repoPath); st.Dirty {
		t.Fatalf("expected clean repo after discard")
	}
	// Trim to ignore autocrlf line-ending normalization on Windows.
	if got := strings.TrimSpace(readFile(t, filepath.Join(repoPath, "a.txt"))); got != "one" {
		t.Fatalf("a.txt = %q, want restored to \"one\"", got)
	}

	// The feed recorded the successful actions.
	kinds := map[string]bool{}
	for _, e := range feed.Events(0) {
		if e.Detail == "ok" {
			kinds[e.Kind] = true
		}
	}
	if !kinds["git-commit"] || !kinds["git-discard"] {
		t.Fatalf("expected git-commit and git-discard ok events, got %v", kinds)
	}
}

func mustMkdir(t *testing.T, p string) {
	t.Helper()
	if err := os.Mkdir(p, 0o755); err != nil {
		t.Fatal(err)
	}
}

func writeFile(t *testing.T, p, s string) {
	t.Helper()
	if err := os.WriteFile(p, []byte(s), 0o644); err != nil {
		t.Fatal(err)
	}
}

func readFile(t *testing.T, p string) string {
	t.Helper()
	b, err := os.ReadFile(p)
	if err != nil {
		t.Fatal(err)
	}
	return string(b)
}

func runGit(t *testing.T, dir string, args ...string) {
	t.Helper()
	cmd := exec.Command("git", args...)
	cmd.Dir = dir
	if out, err := cmd.CombinedOutput(); err != nil {
		t.Fatalf("git %v: %v\n%s", args, err, out)
	}
}