package objstore

import (
	"bytes"
	"context"
	"errors"
	"os"
	"testing"
	"time"

	"github.com/carlosframework/platform/internal/release"
)

func TestKey(t *testing.T) {
	if got := Key("bab", "titogo"); got != "apps/bab/titogo/store.json" {
		t.Fatalf("Key = %q", got)
	}
}

func TestValidEnvPrefix(t *testing.T) {
	for p, want := range map[string]bool{
		"TITO_S3": true, "CARLOS_STORE": true, "A": true,
		"tito": false, "1X": false, "": false, "_X": false,
		"TOO_LONG_" + string(make([]byte, 40)): false,
	} {
		if ValidEnvPrefix(p) != want {
			t.Errorf("ValidEnvPrefix(%q) != %v", p, want)
		}
	}
}

func TestEnvNames(t *testing.T) {
	b, r, e, ak, sk := EnvNames("TITO_S3")
	if b != "TITO_S3_BUCKET" || r != "TITO_S3_REGION" || e != "TITO_S3_ENDPOINT" ||
		ak != "TITO_S3_ACCESS_KEY" || sk != "TITO_S3_SECRET_KEY" {
		t.Fatalf("EnvNames = %q %q %q %q %q", b, r, e, ak, sk)
	}
}

func TestGetAbsentIsNilNil(t *testing.T) {
	s := release.NewDirStore(t.TempDir())
	rec, etag, err := Get(context.Background(), s, "bab", "titogo")
	if rec != nil || etag != "" || err != nil {
		t.Fatalf("absent: rec=%v etag=%q err=%v", rec, etag, err)
	}
}

func TestPutGetRoundTripAndCAS(t *testing.T) {
	ctx := context.Background()
	s := release.NewDirStore(t.TempDir())
	rec := &Record{App: "titogo", Declared: &Declared{EnvPrefix: "TITO_S3"}}
	etag, err := Put(ctx, s, "bab", "titogo", rec, "")
	if err != nil {
		t.Fatal(err)
	}
	got, gotTag, err := Get(ctx, s, "bab", "titogo")
	if err != nil || got == nil || got.Schema != Schema || got.Declared.EnvPrefix != "TITO_S3" {
		t.Fatalf("Get = %+v, %v", got, err)
	}
	if gotTag != etag {
		t.Fatalf("etag mismatch %q vs %q", gotTag, etag)
	}
	// create-only Put on an existing record loses
	if _, err := Put(ctx, s, "bab", "titogo", rec, ""); !errors.Is(err, release.ErrCASConflict) {
		t.Fatalf("create-only over existing: %v", err)
	}
	// stale etag loses
	rec.Grant = &GrantBlock{Backend: "aws"}
	if _, err := Put(ctx, s, "bab", "titogo", rec, etag); err != nil {
		t.Fatal(err)
	}
	if _, err := Put(ctx, s, "bab", "titogo", rec, etag); !errors.Is(err, release.ErrCASConflict) {
		t.Fatalf("stale etag: %v", err)
	}
}

// RevertIn undoes the caller's own write and nothing else: it deletes a
// record the caller created, restores the exact prior bytes of one it
// rewrote, and leaves a record that moved past the caller's etag.
func TestRevertIn(t *testing.T) {
	ctx := context.Background()
	s := release.NewDirStore(t.TempDir())
	key := KeyIn("bab", "shop", "canary")
	decl := func(by string) *Record {
		return &Record{Declared: &Declared{EnvPrefix: DefaultEnvPrefix, At: time.Now().UTC(), By: by}}
	}

	// Created by the caller: deleted.
	tag, err := PutIn(ctx, s, "bab", "shop", "canary", decl("seed"), "")
	if err != nil {
		t.Fatal(err)
	}
	if err := RevertIn(ctx, s, "bab", "shop", "canary", nil, tag); err != nil {
		t.Fatal(err)
	}
	if _, _, err := s.Get(ctx, key); !errors.Is(err, os.ErrNotExist) {
		t.Fatalf("after revert of a created record: %v, want it gone", err)
	}
	// Already gone: left gone.
	if err := RevertIn(ctx, s, "bab", "shop", "canary", nil, tag); err != nil {
		t.Fatalf("revert of a missing record = %v, want nil", err)
	}

	// Rewritten by the caller: the prior bytes, exactly.
	prior := []byte("{\"schema\":1,\"app\":\"shop\",\"environment\":\"canary\",\"declared\":{\"env_prefix\":\"SHOP_FILES\",\"at\":\"2026-10-01T00:00:00Z\",\"by\":\"alice@example.com\"}}\n")
	prevTag, err := s.Put(ctx, key, prior, "")
	if err != nil {
		t.Fatal(err)
	}
	tag, err = PutIn(ctx, s, "bab", "shop", "canary", decl("seed"), prevTag)
	if err != nil {
		t.Fatal(err)
	}
	if err := RevertIn(ctx, s, "bab", "shop", "canary", prior, tag); err != nil {
		t.Fatal(err)
	}
	if got, _, _ := s.Get(ctx, key); !bytes.Equal(got, prior) {
		t.Fatalf("after revert = %s, want %s", got, prior)
	}

	// Moved past the caller's write: left as it is.
	_, cur, _ := s.Get(ctx, key)
	tag, err = PutIn(ctx, s, "bab", "shop", "canary", decl("seed"), cur)
	if err != nil {
		t.Fatal(err)
	}
	if _, err := PutIn(ctx, s, "bab", "shop", "canary", decl("someone-else"), tag); err != nil {
		t.Fatal(err)
	}
	before, _, _ := s.Get(ctx, key)
	for _, prev := range [][]byte{nil, prior} {
		if err := RevertIn(ctx, s, "bab", "shop", "canary", prev, tag); !errors.Is(err, release.ErrCASConflict) {
			t.Fatalf("revert (prev %q) past another write = %v, want ErrCASConflict", prev, err)
		}
		if after, _, _ := s.Get(ctx, key); !bytes.Equal(after, before) {
			t.Fatalf("record after a refused revert = %s, want %s", after, before)
		}
	}
}