package buildstep

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"os"
	"path/filepath"
	"reflect"
	"strings"
	"testing"

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

func hexOf(s string) string { h := sha256.Sum256([]byte(s)); return hex.EncodeToString(h[:]) }

func writeTreeFile(t *testing.T, root, name, content string) {
	t.Helper()
	p := filepath.Join(root, filepath.FromSlash(name))
	if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(p, []byte(content), 0o644); err != nil {
		t.Fatal(err)
	}
}

// ModuleTrees answers, for each directory holding a module.json (the root as "."), the tree id git gives, the sha256 of
// module.json and of each lock file present, and reads them from the workspace.
func TestModuleTreesAnswersTreeManifestAndLocksPerModuleDirectory(t *testing.T) {
	root := t.TempDir()
	writeTreeFile(t, root, "module.json", `{"root":1}`)
	writeTreeFile(t, root, "go.sum", "rootsum")
	writeTreeFile(t, root, "modules/a/module.json", `{"a":1}`)
	writeTreeFile(t, root, "modules/a/go.sum", "asum")
	writeTreeFile(t, root, "modules/a/package-lock.json", "alock")
	writeTreeFile(t, root, "modules/b/module.json", `{"b":1}`)
	merge := strings.Repeat("c", 40)
	var calls []string
	var envs [][]string
	run := func(ctx context.Context, env []string, name string, args ...string) forgekey.Ran {
		calls = append(calls, name+" "+strings.Join(args[2:], " "))
		envs = append(envs, env)
		switch args[2] {
		case "ls-files":
			return forgekey.Ran{Stdout: "module.json\nmodules/a/module.json\nmodules/b/module.json\n"}
		case "rev-parse":
			return forgekey.Ran{Stdout: "tree-of-" + args[3] + "\n"}
		}
		return forgekey.Ran{Status: 1, Stderr: "unexpected"}
	}
	got, err := ModuleTrees(context.Background(), run, []string{"X=1"}, root, merge)
	if err != nil {
		t.Fatal(err)
	}
	want := map[string]ModuleTree{
		".":         {Tree: "tree-of-" + merge + "^{tree}", Manifest: hexOf(`{"root":1}`), Locks: map[string]string{"go.sum": hexOf("rootsum")}},
		"modules/a": {Tree: "tree-of-" + merge + ":modules/a", Manifest: hexOf(`{"a":1}`), Locks: map[string]string{"go.sum": hexOf("asum"), "package-lock.json": hexOf("alock")}},
		"modules/b": {Tree: "tree-of-" + merge + ":modules/b", Manifest: hexOf(`{"b":1}`)},
	}
	if !reflect.DeepEqual(got, want) {
		t.Errorf("trees = %+v\nwant %+v", got, want)
	}
	if got["modules/b"].Locks != nil {
		t.Error("a module with no lock file carries a lock map")
	}
	for _, e := range envs {
		if len(e) != 1 || e[0] != "X=1" {
			t.Errorf("git ran with env %v, want the one given", e)
		}
	}
}

func TestModuleTreesFailsNamingTheGitCommandOrTheUnreadableManifest(t *testing.T) {
	root := t.TempDir()
	fail := func(on string) forgekey.Runner {
		return func(ctx context.Context, env []string, name string, args ...string) forgekey.Ran {
			if args[2] == on {
				return forgekey.Ran{Status: 128, Stderr: "fatal: no\n"}
			}
			return forgekey.Ran{Stdout: "modules/a/module.json\n"}
		}
	}
	for _, on := range []string{"ls-files", "rev-parse"} {
		if _, err := ModuleTrees(context.Background(), fail(on), nil, root, sha); err == nil || !strings.Contains(err.Error(), on) || !strings.Contains(err.Error(), "fatal: no") {
			t.Errorf("%s failing: %v", on, err)
		}
	}
	if _, err := ModuleTrees(context.Background(), fail("none"), nil, root, sha); err == nil {
		t.Error("a module.json that is not in the workspace was read")
	}
}