package store

import (
	"encoding/json"
	"io/ioutil"
	"os"
	"path/filepath"
	"testing"
	"time"
)

type mockSnapshotSink struct {
	*os.File
}

func (m *mockSnapshotSink) ID() string {
	return "1"
}

func (m *mockSnapshotSink) Cancel() error {
	return nil
}

func Test_OpenStoreSingleNode(t *testing.T) {
	s := mustNewStore(true)
	defer os.RemoveAll(s.Path())

	if err := s.Open(true); err != nil {
		t.Fatalf("failed to open single-node store: %s", err.Error())
	}
}

func Test_OpenStoreCloseSingleNode(t *testing.T) {
	s := mustNewStore(true)
	defer os.RemoveAll(s.Path())

	if err := s.Open(true); err != nil {
		t.Fatalf("failed to open single-node store: %s", err.Error())
	}
	if err := s.Close(true); err != nil {
		t.Fatalf("failed to close single-node store: %s", err.Error())
	}
}

func Test_SingleNodeInMemExecuteQuery(t *testing.T) {
	s := mustNewStore(true)
	defer os.RemoveAll(s.Path())

	if err := s.Open(true); err != nil {
		t.Fatalf("failed to open single-node store: %s", err.Error())
	}
	defer s.Close(true)
	s.WaitForLeader(10 * time.Second)

	queries := []string{
		`CREATE TABLE foo (id INTEGER NOT NULL PRIMARY KEY, name TEXT)`,
		`INSERT INTO foo(id, name) VALUES(1, "fiona")`,
	}
	_, err := s.Execute(queries, false, false)
	if err != nil {
		t.Fatalf("failed to execute on single node: %s", err.Error())
	}
	r, err := s.Query([]string{`SELECT * FROM foo`}, false, false, None)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}
	r, err = s.Query([]string{`SELECT * FROM foo`}, false, false, None)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}
	r, err = s.Query([]string{`SELECT * FROM foo`}, false, false, None)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}
	if exp, got := `["id","name"]`, asJSON(r[0].Columns); exp != got {
		t.Fatalf("unexpected results for query\nexp: %s\ngot: %s", exp, got)
	}
	if exp, got := `[[1,"fiona"]]`, asJSON(r[0].Values); exp != got {
		t.Fatalf("unexpected results for query\nexp: %s\ngot: %s", exp, got)
	}
}

func Test_SingleNodeFileExecuteQuery(t *testing.T) {
	s := mustNewStore(false)
	defer os.RemoveAll(s.Path())

	if err := s.Open(true); err != nil {
		t.Fatalf("failed to open single-node store: %s", err.Error())
	}
	defer s.Close(true)
	s.WaitForLeader(10 * time.Second)

	queries := []string{
		`CREATE TABLE foo (id INTEGER NOT NULL PRIMARY KEY, name TEXT)`,
		`INSERT INTO foo(id, name) VALUES(1, "fiona")`,
	}
	_, err := s.Execute(queries, false, false)
	if err != nil {
		t.Fatalf("failed to execute on single node: %s", err.Error())
	}
	r, err := s.Query([]string{`SELECT * FROM foo`}, false, false, None)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}
	r, err = s.Query([]string{`SELECT * FROM foo`}, false, false, None)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}
	r, err = s.Query([]string{`SELECT * FROM foo`}, false, false, None)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}
	if exp, got := `["id","name"]`, asJSON(r[0].Columns); exp != got {
		t.Fatalf("unexpected results for query\nexp: %s\ngot: %s", exp, got)
	}
	if exp, got := `[[1,"fiona"]]`, asJSON(r[0].Values); exp != got {
		t.Fatalf("unexpected results for query\nexp: %s\ngot: %s", exp, got)
	}
}

func Test_SingleNodeExecuteQueryTx(t *testing.T) {
	s := mustNewStore(true)
	defer os.RemoveAll(s.Path())

	if err := s.Open(true); err != nil {
		t.Fatalf("failed to open single-node store: %s", err.Error())
	}
	defer s.Close(true)
	s.WaitForLeader(10 * time.Second)

	queries := []string{
		`CREATE TABLE foo (id INTEGER NOT NULL PRIMARY KEY, name TEXT)`,
		`INSERT INTO foo(id, name) VALUES(1, "fiona")`,
	}
	_, err := s.Execute(queries, false, true)
	if err != nil {
		t.Fatalf("failed to execute on single node: %s", err.Error())
	}
	r, err := s.Query([]string{`SELECT * FROM foo`}, false, true, None)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}
	r, err = s.Query([]string{`SELECT * FROM foo`}, false, true, Weak)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}
	r, err = s.Query([]string{`SELECT * FROM foo`}, false, true, Strong)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}
	if exp, got := `["id","name"]`, asJSON(r[0].Columns); exp != got {
		t.Fatalf("unexpected results for query\nexp: %s\ngot: %s", exp, got)
	}
	if exp, got := `[[1,"fiona"]]`, asJSON(r[0].Values); exp != got {
		t.Fatalf("unexpected results for query\nexp: %s\ngot: %s", exp, got)
	}
	_, err = s.Execute(queries, false, true)
	if err != nil {
		t.Fatalf("failed to execute on single node: %s", err.Error())
	}
}

func Test_MultiNodeExecuteQuery(t *testing.T) {
	s0 := mustNewStore(true)
	defer os.RemoveAll(s0.Path())
	if err := s0.Open(true); err != nil {
		t.Fatalf("failed to open node for multi-node test: %s", err.Error())
	}
	defer s0.Close(true)
	s0.WaitForLeader(10 * time.Second)

	s1 := mustNewStore(true)
	defer os.RemoveAll(s1.Path())
	if err := s1.Open(false); err != nil {
		t.Fatalf("failed to open node for multi-node test: %s", err.Error())
	}
	defer s1.Close(true)

	// Join the second node to the first.
	if err := s0.Join(s1.Addr().String()); err != nil {
		t.Fatalf("failed to join to node at %s: %s", s0.Addr().String(), err.Error())
	}

	queries := []string{
		`CREATE TABLE foo (id INTEGER NOT NULL PRIMARY KEY, name TEXT)`,
		`INSERT INTO foo(id, name) VALUES(1, "fiona")`,
	}
	_, err := s0.Execute(queries, false, false)
	if err != nil {
		t.Fatalf("failed to execute on single node: %s", err.Error())
	}
	r, err := s0.Query([]string{`SELECT * FROM foo`}, false, false, None)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}
	if exp, got := `["id","name"]`, asJSON(r[0].Columns); exp != got {
		t.Fatalf("unexpected results for query\nexp: %s\ngot: %s", exp, got)
	}
	if exp, got := `[[1,"fiona"]]`, asJSON(r[0].Values); exp != got {
		t.Fatalf("unexpected results for query\nexp: %s\ngot: %s", exp, got)
	}

	// Wait until the 3 log entries have been applied to the follower,
	// and then query.
	if err := s1.WaitForAppliedIndex(3, 5*time.Second); err != nil {
		t.Fatalf("error waiting for follower to apply index: %s:", err.Error())
	}
	r, err = s1.Query([]string{`SELECT * FROM foo`}, false, false, Weak)
	if err == nil {
		t.Fatalf("successfully queried non-leader node")
	}
	r, err = s1.Query([]string{`SELECT * FROM foo`}, false, false, Strong)
	if err == nil {
		t.Fatalf("successfully queried non-leader node")
	}
	r, err = s1.Query([]string{`SELECT * FROM foo`}, false, false, None)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}
	if exp, got := `["id","name"]`, asJSON(r[0].Columns); exp != got {
		t.Fatalf("unexpected results for query\nexp: %s\ngot: %s", exp, got)
	}
	if exp, got := `[[1,"fiona"]]`, asJSON(r[0].Values); exp != got {
		t.Fatalf("unexpected results for query\nexp: %s\ngot: %s", exp, got)
	}
}

func Test_SingleNodeSnapshotOnDisk(t *testing.T) {
	s := mustNewStore(false)
	defer os.RemoveAll(s.Path())

	if err := s.Open(true); err != nil {
		t.Fatalf("failed to open single-node store: %s", err.Error())
	}
	defer s.Close(true)
	s.WaitForLeader(10 * time.Second)

	queries := []string{
		`CREATE TABLE foo (id INTEGER NOT NULL PRIMARY KEY, name TEXT)`,
		`INSERT INTO foo(id, name) VALUES(1, "fiona")`,
	}
	_, err := s.Execute(queries, false, false)
	if err != nil {
		t.Fatalf("failed to execute on single node: %s", err.Error())
	}
	_, err = s.Query([]string{`SELECT * FROM foo`}, false, false, None)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}

	// Snap the node and write to disk.
	f, err := s.Snapshot()
	if err != nil {
		t.Fatalf("failed to snapshot node: %s", err.Error())
	}

	snapDir := mustTempDir()
	defer os.RemoveAll(snapDir)
	snapFile, err := os.Create(filepath.Join(snapDir, "snapshot"))
	if err != nil {
		t.Fatalf("failed to create snapshot file: %s", err.Error())
	}
	sink := &mockSnapshotSink{snapFile}
	if err := f.Persist(sink); err != nil {
		t.Fatalf("failed to persist snapshot to disk: %s", err.Error())
	}

	// Check restoration.
	snapFile, err = os.Open(filepath.Join(snapDir, "snapshot"))
	if err != nil {
		t.Fatalf("failed to open snapshot file: %s", err.Error())
	}
	if err := s.Restore(snapFile); err != nil {
		t.Fatalf("failed to restore snapshot from disk: %s", err.Error())
	}

	// Ensure database is back in the correct state.
	r, err := s.Query([]string{`SELECT * FROM foo`}, false, false, None)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}
	if exp, got := `["id","name"]`, asJSON(r[0].Columns); exp != got {
		t.Fatalf("unexpected results for query\nexp: %s\ngot: %s", exp, got)
	}
	if exp, got := `[[1,"fiona"]]`, asJSON(r[0].Values); exp != got {
		t.Fatalf("unexpected results for query\nexp: %s\ngot: %s", exp, got)
	}
}

func Test_SingleNodeSnapshotInMem(t *testing.T) {
	s := mustNewStore(true)
	defer os.RemoveAll(s.Path())

	if err := s.Open(true); err != nil {
		t.Fatalf("failed to open single-node store: %s", err.Error())
	}
	defer s.Close(true)
	s.WaitForLeader(10 * time.Second)

	queries := []string{
		`CREATE TABLE foo (id INTEGER NOT NULL PRIMARY KEY, name TEXT)`,
		`INSERT INTO foo(id, name) VALUES(1, "fiona")`,
	}
	_, err := s.Execute(queries, false, false)
	if err != nil {
		t.Fatalf("failed to execute on single node: %s", err.Error())
	}
	_, err = s.Query([]string{`SELECT * FROM foo`}, false, false, None)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}

	// Snap the node and write to disk.
	f, err := s.Snapshot()
	if err != nil {
		t.Fatalf("failed to snapshot node: %s", err.Error())
	}

	snapDir := mustTempDir()
	defer os.RemoveAll(snapDir)
	snapFile, err := os.Create(filepath.Join(snapDir, "snapshot"))
	if err != nil {
		t.Fatalf("failed to create snapshot file: %s", err.Error())
	}
	sink := &mockSnapshotSink{snapFile}
	if err := f.Persist(sink); err != nil {
		t.Fatalf("failed to persist snapshot to disk: %s", err.Error())
	}

	// Check restoration.
	snapFile, err = os.Open(filepath.Join(snapDir, "snapshot"))
	if err != nil {
		t.Fatalf("failed to open snapshot file: %s", err.Error())
	}
	if err := s.Restore(snapFile); err != nil {
		t.Fatalf("failed to restore snapshot from disk: %s", err.Error())
	}

	// Ensure database is back in the correct state.
	r, err := s.Query([]string{`SELECT * FROM foo`}, false, false, None)
	if err != nil {
		t.Fatalf("failed to query single node: %s", err.Error())
	}
	if exp, got := `["id","name"]`, asJSON(r[0].Columns); exp != got {
		t.Fatalf("unexpected results for query\nexp: %s\ngot: %s", exp, got)
	}
	if exp, got := `[[1,"fiona"]]`, asJSON(r[0].Values); exp != got {
		t.Fatalf("unexpected results for query\nexp: %s\ngot: %s", exp, got)
	}
}

func mustNewStore(inmem bool) *Store {
	path := mustTempDir()
	defer os.RemoveAll(path)

	cfg := NewDBConfig("", inmem)
	s := New(cfg, path, "localhost:0")
	if s == nil {
		panic("failed to create new store")
	}
	return s
}

func mustTempDir() string {
	var err error
	path, err := ioutil.TempDir("", "rqlilte-test-")
	if err != nil {
		panic("failed to create temp dir")
	}
	return path
}

func asJSON(v interface{}) string {
	b, err := json.Marshal(v)
	if err != nil {
		panic("failed to JSON marshal value")
	}
	return string(b)
}