package git

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

// TestWriteFileCommit creates files (including nested paths) directly on a
// bare repository through git plumbing, without a working tree.
func TestWriteFileCommit(t *testing.T) {
	ctx := context.Background()
	tmp := t.TempDir()

	repoPath := filepath.Join(tmp, "repo.git")
	if err := InitBare(ctx, repoPath, "main"); err != nil {
		t.Fatalf("InitBare: %v", err)
	}

	work := filepath.Join(tmp, "work")
	if err := os.MkdirAll(work, 0o755); err != nil {
		t.Fatalf("mkdir: %v", err)
	}
	run := func(dir string, args ...string) {
		t.Helper()
		cmd := exec.CommandContext(ctx, "git", args...)
		cmd.Dir = dir
		if out, err := cmd.CombinedOutput(); err != nil {
			t.Fatalf("git %v: %v (%s)", args, err, string(out))
		}
	}
	run(work, "init", "-b", "main")
	run(work, "config", "user.name", "Alice")
	run(work, "config", "user.email", "alice@example.com")
	if err := os.WriteFile(filepath.Join(work, "README.md"), []byte("# Repo\n"), 0o644); err != nil {
		t.Fatalf("write: %v", err)
	}
	run(work, "add", ".")
	run(work, "commit", "-m", "initial")
	run(work, "push", repoPath, "main")

	hash, err := WriteFileCommit(ctx, repoPath, "main", "docs/guide.md", []byte("hello\n"), "Add docs/guide.md", "Alice", "alice@example.com")
	if err != nil {
		t.Fatalf("WriteFileCommit: %v", err)
	}
	if hash == "" {
		t.Fatalf("expected commit hash")
	}

	blob, err := ReadBlob(ctx, repoPath, "main", "docs/guide.md")
	if err != nil {
		t.Fatalf("ReadBlob: %v", err)
	}
	if string(blob.Data) != "hello\n" {
		t.Fatalf("unexpected blob content: %q", string(blob.Data))
	}

	out, err := runGit(ctx, repoPath, 10_000_000_000, "log", "-1", "--format=%s|%an|%ae", "main")
	if err != nil {
		t.Fatalf("log: %v", err)
	}
	line := strings.TrimSpace(string(out))
	if line != "Add docs/guide.md|Alice|alice@example.com" {
		t.Fatalf("unexpected commit metadata: %s", line)
	}

	// A second write replaces the file and keeps history.
	if _, err := WriteFileCommit(ctx, repoPath, "main", "docs/guide.md", []byte("hello v2\n"), "Update docs/guide.md", "Bob", "bob@example.com"); err != nil {
		t.Fatalf("second WriteFileCommit: %v", err)
	}
	if n := CountCommits(ctx, repoPath, "main"); n != 3 {
		t.Fatalf("expected 3 commits, got %d", n)
	}
	blob, err = ReadBlob(ctx, repoPath, "main", "docs/guide.md")
	if err != nil {
		t.Fatalf("ReadBlob v2: %v", err)
	}
	if string(blob.Data) != "hello v2\n" {
		t.Fatalf("unexpected blob content: %q", string(blob.Data))
	}

	// Invalid paths and refs must be rejected.
	if _, err := WriteFileCommit(ctx, repoPath, "main", "../evil.txt", []byte("x"), "", "Alice", "alice@example.com"); err == nil {
		t.Fatalf("expected invalid path to be rejected")
	}
	if _, err := WriteFileCommit(ctx, repoPath, "main", ".git/config", []byte("x"), "", "Alice", "alice@example.com"); err == nil {
		t.Fatalf("expected .git path to be rejected")
	}
	if _, err := WriteFileCommit(ctx, repoPath, "no-such-branch", "file.txt", []byte("x"), "", "Alice", "alice@example.com"); err == nil {
		t.Fatalf("expected missing branch to be rejected")
	}
}