package blog_test

import (
	"io/fs"
	"os"
	"path/filepath"
	"regexp"
	"slices"
	"strings"
	"testing"

	"git.golem15.com/golem15/summercms/internal/build"
)

// TestScaffoldLayout pins the walkthrough to the scaffolder: running the
// make commands the porting page lists for acme.blog, in its order, in a
// copy of the examples/hello application, must produce exactly the files of
// this plugin (without its tests, and with migration timestamps normalised). The
// in-repository copy has no go.mod or go.sum because it lives in the
// framework module; those two are left out of the scaffolder's set.
func TestScaffoldLayout(t *testing.T) {
	// The make commands run go mod tidy; keep it on the module cache.
	t.Setenv("GOPROXY", "off")
	root, err := filepath.Abs(filepath.Join("..", "..", ".."))
	if err != nil {
		t.Fatal(err)
	}
	app := copyApp(t, filepath.Join(root, "examples", "hello"), root)

	ctx := t.Context()
	if _, err := build.MakePlugin(ctx, app, "acme.blog"); err != nil {
		t.Fatalf("MakePlugin: %v", err)
	}
	if _, err := build.MakeModel(ctx, app, "acme.blog", "Post", false); err != nil {
		t.Fatalf("MakeModel: %v", err)
	}
	if _, err := build.MakeMigration(ctx, app, "acme.blog", "AddPublishedAt"); err != nil {
		t.Fatalf("MakeMigration: %v", err)
	}
	if _, err := build.MakeAdminController(ctx, app, "acme.blog", "Posts"); err != nil {
		t.Fatalf("MakeAdminController: %v", err)
	}
	if _, err := build.MakeCommand(ctx, app, "acme.blog", "Publish"); err != nil {
		t.Fatalf("MakeCommand: %v", err)
	}

	scaffolded := fileSet(t, filepath.Join(app, "plugins", "blog"), func(rel string) bool {
		return rel != "go.mod" && rel != "go.sum"
	})
	walkthrough := fileSet(t, ".", func(rel string) bool {
		return !strings.HasSuffix(rel, "_test.go")
	})
	var missing, extra []string
	for _, f := range scaffolded {
		if !slices.Contains(walkthrough, f) {
			missing = append(missing, f)
		}
	}
	for _, f := range walkthrough {
		if !slices.Contains(scaffolded, f) {
			extra = append(extra, f)
		}
	}
	if len(missing) > 0 || len(extra) > 0 {
		t.Errorf("docs/examples/blog differs from the scaffolder output\nscaffolded but missing here: %v\nhere but not scaffolded: %v", missing, extra)
	}
}

var migrationStamp = regexp.MustCompile(`^updates/\d{14}_`)

// fileSet returns the sorted relative paths of the files under dir that keep
// accepts, with a leading 14-digit migration timestamp replaced by a token.
func fileSet(t *testing.T, dir string, keep func(rel string) bool) []string {
	t.Helper()
	var out []string
	err := filepath.WalkDir(dir, func(p string, d fs.DirEntry, err error) error {
		if err != nil || d.IsDir() {
			return err
		}
		rel, err := filepath.Rel(dir, p)
		if err != nil {
			return err
		}
		rel = filepath.ToSlash(rel)
		if keep(rel) {
			out = append(out, migrationStamp.ReplaceAllString(rel, "updates/TIMESTAMP_"))
		}
		return nil
	})
	if err != nil {
		t.Fatal(err)
	}
	slices.Sort(out)
	return out
}

// copyApp copies the application at src into a temporary directory, without
// its bin/ directory, and points every go.mod replace of the framework
// module at framework.
func copyApp(t *testing.T, src, framework string) string {
	t.Helper()
	const module = "git.golem15.com/golem15/summercms"
	dst := t.TempDir()
	err := filepath.WalkDir(src, func(p string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		rel, err := filepath.Rel(src, p)
		if err != nil {
			return err
		}
		if d.IsDir() {
			if rel == "bin" {
				return filepath.SkipDir
			}
			return os.MkdirAll(filepath.Join(dst, rel), 0o755)
		}
		data, err := os.ReadFile(p)
		if err != nil {
			return err
		}
		if d.Name() == "go.mod" {
			lines := strings.Split(string(data), "\n")
			for i, line := range lines {
				trimmed := strings.TrimSpace(strings.TrimPrefix(strings.TrimSpace(line), "replace "))
				if strings.HasPrefix(trimmed, module+" =>") {
					indent := line[:len(line)-len(strings.TrimLeft(line, " \t"))]
					prefix := ""
					if strings.HasPrefix(strings.TrimSpace(line), "replace ") {
						prefix = "replace "
					}
					lines[i] = indent + prefix + module + " => " + framework
				}
			}
			data = []byte(strings.Join(lines, "\n"))
		}
		return os.WriteFile(filepath.Join(dst, rel), data, 0o644)
	})
	if err != nil {
		t.Fatal(err)
	}
	return dst
}