// Tests use a global viper instance for configuration,
// making parallel execution unsafe.
//
//nolint:paralleltest
package service_test

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"testing"

	"go.uber.org/fx"
	"go.uber.org/fx/fxtest"
	"golang.org/x/crypto/bcrypt"
	"sneak.berlin/go/neoirc/internal/broker"
	"sneak.berlin/go/neoirc/internal/config"
	"sneak.berlin/go/neoirc/internal/db"
	"sneak.berlin/go/neoirc/internal/globals"
	"sneak.berlin/go/neoirc/internal/logger"
	"sneak.berlin/go/neoirc/internal/service"
	"sneak.berlin/go/neoirc/pkg/irc"
)

func TestMain(m *testing.M) {
	db.SetBcryptCost(bcrypt.MinCost)
	os.Exit(m.Run())
}

// testEnv holds all dependencies for a service test.
type testEnv struct {
	svc    *service.Service
	db     *db.Database
	broker *broker.Broker
	app    *fxtest.App
}

func newTestEnv(t *testing.T) *testEnv {
	t.Helper()

	dbURL := fmt.Sprintf(
		"file:svc_test_%p?mode=memory&cache=shared",
		t,
	)

	var (
		database *db.Database
		svc      *service.Service
	)

	brk := broker.New()

	app := fxtest.New(t,
		fx.Provide(
			func() *globals.Globals {
				return &globals.Globals{ //nolint:exhaustruct
					Appname: "neoirc-test",
					Version: "test",
				}
			},
			logger.New,
			func(
				lifecycle fx.Lifecycle,
				globs *globals.Globals,
				log *logger.Logger,
			) (*config.Config, error) {
				cfg, err := config.New(
					lifecycle, config.Params{ //nolint:exhaustruct
						Globals: globs, Logger: log,
					},
				)
				if err != nil {
					return nil, fmt.Errorf(
						"test config: %w", err,
					)
				}

				cfg.DBURL = dbURL
				cfg.Port = 0
				cfg.OperName = "admin"
				cfg.OperPassword = "secret"

				return cfg, nil
			},
			func(
				lifecycle fx.Lifecycle,
				log *logger.Logger,
				cfg *config.Config,
			) (*db.Database, error) {
				return db.New(lifecycle, db.Params{ //nolint:exhaustruct
					Logger: log, Config: cfg,
				})
			},
			func() *broker.Broker { return brk },
			service.New,
		),
		fx.Populate(&database, &svc),
	)

	app.RequireStart()

	t.Cleanup(func() {
		app.RequireStop()
	})

	return &testEnv{
		svc:    svc,
		db:     database,
		broker: brk,
		app:    app,
	}
}

// createSession is a test helper that creates a session
// and returns the session ID.
func createSession(
	ctx context.Context,
	t *testing.T,
	database *db.Database,
	nick string,
) int64 {
	t.Helper()

	sessionID, _, _, err := database.CreateSession(
		ctx, nick, nick, "localhost", "127.0.0.1",
	)
	if err != nil {
		t.Fatalf("create session %s: %v", nick, err)
	}

	return sessionID
}

func TestFanOut(t *testing.T) {
	env := newTestEnv(t)
	ctx := t.Context()

	sid1 := createSession(ctx, t, env.db, "alice")
	sid2 := createSession(ctx, t, env.db, "bob")

	body, _ := json.Marshal([]string{"hello"}) //nolint:errchkjson

	dbID, uuid, err := env.svc.FanOut(
		ctx, irc.CmdPrivmsg, "alice", "#test",
		nil, body, nil,
		[]int64{sid1, sid2},
	)
	if err != nil {
		t.Fatalf("FanOut: %v", err)
	}

	if dbID == 0 {
		t.Error("expected non-zero dbID")
	}

	if uuid == "" {
		t.Error("expected non-empty UUID")
	}
}

func TestJoinChannel(t *testing.T) {
	env := newTestEnv(t)
	ctx := t.Context()

	sid := createSession(ctx, t, env.db, "alice")

	result, err := env.svc.JoinChannel(
		ctx, sid, "alice", "#general", "",
	)
	if err != nil {
		t.Fatalf("JoinChannel: %v", err)
	}

	if result.ChannelID == 0 {
		t.Error("expected non-zero channel ID")
	}

	if !result.IsCreator {
		t.Error("first joiner should be creator")
	}

	// Second user joins — not creator.
	sid2 := createSession(ctx, t, env.db, "bob")

	result2, err := env.svc.JoinChannel(
		ctx, sid2, "bob", "#general", "",
	)
	if err != nil {
		t.Fatalf("JoinChannel bob: %v", err)
	}

	if result2.IsCreator {
		t.Error("second joiner should not be creator")
	}

	if result2.ChannelID != result.ChannelID {
		t.Error("both should join the same channel")
	}
}

func TestPartChannel(t *testing.T) {
	env := newTestEnv(t)
	ctx := t.Context()

	sid := createSession(ctx, t, env.db, "alice")

	_, err := env.svc.JoinChannel(
		ctx, sid, "alice", "#general", "",
	)
	if err != nil {
		t.Fatalf("JoinChannel: %v", err)
	}

	err = env.svc.PartChannel(
		ctx, sid, "alice", "#general", "bye",
	)
	if err != nil {
		t.Fatalf("PartChannel: %v", err)
	}

	// Parting a non-existent channel returns error.
	err = env.svc.PartChannel(
		ctx, sid, "alice", "#nonexistent", "",
	)
	if err == nil {
		t.Error("expected error for non-existent channel")
	}

	var ircErr *service.IRCError
	if !errors.As(err, &ircErr) {
		t.Errorf("expected IRCError, got %T", err)
	}
}

func TestSendChannelMessage(t *testing.T) {
	env := newTestEnv(t)
	ctx := t.Context()

	sid1 := createSession(ctx, t, env.db, "alice")
	sid2 := createSession(ctx, t, env.db, "bob")

	_, err := env.svc.JoinChannel(
		ctx, sid1, "alice", "#chat", "",
	)
	if err != nil {
		t.Fatalf("join alice: %v", err)
	}

	_, err = env.svc.JoinChannel(
		ctx, sid2, "bob", "#chat", "",
	)
	if err != nil {
		t.Fatalf("join bob: %v", err)
	}

	body, _ := json.Marshal([]string{"hello world"}) //nolint:errchkjson

	dbID, uuid, err := env.svc.SendChannelMessage(
		ctx, sid1, "alice",
		irc.CmdPrivmsg, "#chat", body, nil,
	)
	if err != nil {
		t.Fatalf("SendChannelMessage: %v", err)
	}

	if dbID == 0 {
		t.Error("expected non-zero dbID")
	}

	if uuid == "" {
		t.Error("expected non-empty UUID")
	}

	// Non-member cannot send.
	sid3 := createSession(ctx, t, env.db, "charlie")

	_, _, err = env.svc.SendChannelMessage(
		ctx, sid3, "charlie",
		irc.CmdPrivmsg, "#chat", body, nil,
	)
	if err == nil {
		t.Error("expected error for non-member send")
	}
}

func TestBroadcastQuit(t *testing.T) {
	env := newTestEnv(t)
	ctx := t.Context()

	sid1 := createSession(ctx, t, env.db, "alice")
	sid2 := createSession(ctx, t, env.db, "bob")

	_, err := env.svc.JoinChannel(
		ctx, sid1, "alice", "#room", "",
	)
	if err != nil {
		t.Fatalf("join alice: %v", err)
	}

	_, err = env.svc.JoinChannel(
		ctx, sid2, "bob", "#room", "",
	)
	if err != nil {
		t.Fatalf("join bob: %v", err)
	}

	// BroadcastQuit should not panic and should clean up.
	env.svc.BroadcastQuit(
		ctx, sid1, "alice", "Goodbye",
	)

	// Session should be deleted.
	_, lookupErr := env.db.GetSessionByNick(ctx, "alice")
	if lookupErr == nil {
		t.Error("expected session to be deleted after quit")
	}
}

func TestSendChannelMessage_Moderated(t *testing.T) {
	env := newTestEnv(t)
	ctx := t.Context()

	sid1 := createSession(ctx, t, env.db, "alice")
	sid2 := createSession(ctx, t, env.db, "bob")

	result, err := env.svc.JoinChannel(
		ctx, sid1, "alice", "#modchat", "",
	)
	if err != nil {
		t.Fatalf("join alice: %v", err)
	}

	_, err = env.svc.JoinChannel(
		ctx, sid2, "bob", "#modchat", "",
	)
	if err != nil {
		t.Fatalf("join bob: %v", err)
	}

	// Set channel to moderated.
	chID := result.ChannelID
	_ = env.svc.SetChannelFlag(ctx, chID, 'm', true)

	body, _ := json.Marshal([]string{"test"}) //nolint:errchkjson

	// Bob (non-op, non-voiced) should fail to send.
	_, _, err = env.svc.SendChannelMessage(
		ctx, sid2, "bob",
		irc.CmdPrivmsg, "#modchat", body, nil,
	)
	if err == nil {
		t.Error("expected error for non-voiced user in moderated channel")
	}

	// Alice (operator) should succeed.
	_, _, err = env.svc.SendChannelMessage(
		ctx, sid1, "alice",
		irc.CmdPrivmsg, "#modchat", body, nil,
	)
	if err != nil {
		t.Errorf("operator should be able to send in moderated channel: %v", err)
	}
}

func TestQueryUserMode(t *testing.T) {
	env := newTestEnv(t)
	ctx := t.Context()

	sid := createSession(ctx, t, env.db, "alice")

	// Fresh session has no modes.
	modes := env.svc.QueryUserMode(ctx, sid)
	if modes != "+" {
		t.Errorf("expected +, got %s", modes)
	}

	// Set wallops.
	_ = env.db.SetSessionWallops(ctx, sid, true)

	modes = env.svc.QueryUserMode(ctx, sid)
	if modes != "+w" {
		t.Errorf("expected +w, got %s", modes)
	}

	// Set oper.
	_ = env.db.SetSessionOper(ctx, sid, true)

	modes = env.svc.QueryUserMode(ctx, sid)
	if modes != "+ow" {
		t.Errorf("expected +ow, got %s", modes)
	}
}

// applyUserModeCaseState is the subset of session user-mode
// state the rigorous TestApplyUserMode suite asserts on. It
// mirrors the columns (oper, wallops) that the parser is
// permitted to mutate.
type applyUserModeCaseState struct {
	oper    bool
	wallops bool
}

// applyUserModeCase describes one rigor-suite case for
// Service.ApplyUserMode: the pre-call DB state, the mode
// string input, and the expected post-call observable state
// (mode string on success, IRC error code on rejection, and
// persisted session state either way).
type applyUserModeCase struct {
	name         string
	initialState applyUserModeCaseState
	modeStr      string
	wantModes    string
	wantErr      bool
	wantErrCode  irc.IRCMessageType
	wantState    applyUserModeCaseState
}

// applyUserModeCases returns every case listed in sneak's
// review of PR #96 plus a few adjacent ones. Split across
// helpers by category so each stays under funlen.
func applyUserModeCases() []applyUserModeCase {
	cases := applyUserModeHappyPathCases()
	cases = append(cases, applyUserModeSignTransitionCases()...)
	cases = append(cases, applyUserModeMalformedCases()...)
	cases = append(cases, applyUserModeUnknownLetterCases()...)

	return cases
}

// applyUserModeHappyPathCases covers valid single-char and
// multi-char-without-sign-transition mode operations.
func applyUserModeHappyPathCases() []applyUserModeCase {
	return []applyUserModeCase{
		{
			name:         "+w from empty",
			initialState: applyUserModeCaseState{oper: false, wallops: false},
			modeStr:      "+w",
			wantModes:    "+w",
			wantErr:      false,
			wantErrCode:  0,
			wantState:    applyUserModeCaseState{oper: false, wallops: true},
		},
		{
			name:         "-w from +w",
			initialState: applyUserModeCaseState{oper: false, wallops: true},
			modeStr:      "-w",
			wantModes:    "+",
			wantErr:      false,
			wantErrCode:  0,
			wantState:    applyUserModeCaseState{oper: false, wallops: false},
		},
		{
			name:         "-o from +o",
			initialState: applyUserModeCaseState{oper: true, wallops: false},
			modeStr:      "-o",
			wantModes:    "+",
			wantErr:      false,
			wantErrCode:  0,
			wantState:    applyUserModeCaseState{oper: false, wallops: false},
		},
		{
			name:         "-wo from +ow",
			initialState: applyUserModeCaseState{oper: true, wallops: true},
			modeStr:      "-wo",
			wantModes:    "+",
			wantErr:      false,
			wantErrCode:  0,
			wantState:    applyUserModeCaseState{oper: false, wallops: false},
		},
	}
}

// applyUserModeSignTransitionCases covers multi-char mode
// strings where '+' and '-' flip partway through. +o is
// never legal via MODE, so strings containing it must be
// rejected atomically.
func applyUserModeSignTransitionCases() []applyUserModeCase {
	return []applyUserModeCase{
		{
			name:         "+w-o from +o",
			initialState: applyUserModeCaseState{oper: true, wallops: false},
			modeStr:      "+w-o",
			wantModes:    "+w",
			wantErr:      false,
			wantErrCode:  0,
			wantState:    applyUserModeCaseState{oper: false, wallops: true},
		},
		{
			// +o is rejected before any op applies; wallops
			// stays set.
			name:         "-w+o always rejects +o",
			initialState: applyUserModeCaseState{oper: true, wallops: true},
			modeStr:      "-w+o",
			wantModes:    "",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			wantState:    applyUserModeCaseState{oper: true, wallops: true},
		},
		{
			// Wallops must NOT be cleared; oper must NOT be
			// cleared. Rejection is fully atomic.
			name:         "+o-w+w rejects because of +o",
			initialState: applyUserModeCaseState{oper: true, wallops: true},
			modeStr:      "+o-w+w",
			wantModes:    "",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			wantState:    applyUserModeCaseState{oper: true, wallops: true},
		},
	}
}

// applyUserModeMalformedCases covers inputs that lack a
// leading '+' or '-' and inputs that consist of bare signs
// without mode letters. All must be rejected with no side
// effects.
func applyUserModeMalformedCases() []applyUserModeCase {
	return []applyUserModeCase{
		{
			name:         "w no prefix rejects",
			initialState: applyUserModeCaseState{oper: false, wallops: false},
			modeStr:      "w",
			wantModes:    "",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			wantState:    applyUserModeCaseState{oper: false, wallops: false},
		},
		{
			// Prove wallops is NOT cleared — the whole point
			// of sneak's review.
			name: "xw no prefix rejects (would have been" +
				" silently -w before)",
			initialState: applyUserModeCaseState{oper: false, wallops: true},
			modeStr:      "xw",
			wantModes:    "",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			wantState:    applyUserModeCaseState{oper: false, wallops: true},
		},
		{
			name:         "empty string rejects",
			initialState: applyUserModeCaseState{oper: false, wallops: false},
			modeStr:      "",
			wantModes:    "",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			wantState:    applyUserModeCaseState{oper: false, wallops: false},
		},
		{
			name:         "bare + rejects",
			initialState: applyUserModeCaseState{oper: false, wallops: false},
			modeStr:      "+",
			wantModes:    "",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			wantState:    applyUserModeCaseState{oper: false, wallops: false},
		},
		{
			name:         "bare - rejects",
			initialState: applyUserModeCaseState{oper: false, wallops: false},
			modeStr:      "-",
			wantModes:    "",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			wantState:    applyUserModeCaseState{oper: false, wallops: false},
		},
		{
			name:         "+-+ rejects (no mode letters)",
			initialState: applyUserModeCaseState{oper: false, wallops: false},
			modeStr:      "+-+",
			wantModes:    "",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			wantState:    applyUserModeCaseState{oper: false, wallops: false},
		},
	}
}

// applyUserModeUnknownLetterCases covers well-formed prefix
// strings that contain unknown mode letters. Rejection must
// be atomic: any valid letters before the invalid one must
// not persist.
func applyUserModeUnknownLetterCases() []applyUserModeCase {
	return []applyUserModeCase{
		{
			name:         "-x+y rejects unknown -x",
			initialState: applyUserModeCaseState{oper: false, wallops: false},
			modeStr:      "-x+y",
			wantModes:    "",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			wantState:    applyUserModeCaseState{oper: false, wallops: false},
		},
		{
			name:         "+y-x rejects unknown +y",
			initialState: applyUserModeCaseState{oper: false, wallops: false},
			modeStr:      "+y-x",
			wantModes:    "",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			wantState:    applyUserModeCaseState{oper: false, wallops: false},
		},
		{
			name:         "+z unknown mode rejects",
			initialState: applyUserModeCaseState{oper: false, wallops: false},
			modeStr:      "+z",
			wantModes:    "",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			wantState:    applyUserModeCaseState{oper: false, wallops: false},
		},
		{
			// Wallops must NOT be set.
			name: "+wz rejects whole thing; +w side effect" +
				" must NOT persist",
			initialState: applyUserModeCaseState{oper: false, wallops: false},
			modeStr:      "+wz",
			wantModes:    "",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			wantState:    applyUserModeCaseState{oper: false, wallops: false},
		},
		{
			name: "+wo rejects whole thing; +w side effect" +
				" must NOT persist",
			initialState: applyUserModeCaseState{oper: false, wallops: false},
			modeStr:      "+wo",
			wantModes:    "",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			wantState:    applyUserModeCaseState{oper: false, wallops: false},
		},
	}
}

// TestApplyUserMode is the rigorous table-driven suite for
// the shared user-mode parser. It covers every case listed
// in sneak's review of PR #96 plus a few adjacent ones.
// Each case asserts the resulting mode string AND the
// persisted session state, to prove that rejected input
// leaves no side effects.
func TestApplyUserMode(t *testing.T) {
	for _, testCase := range applyUserModeCases() {
		t.Run(testCase.name, func(t *testing.T) {
			runApplyUserModeCase(t, testCase)
		})
	}
}

// runApplyUserModeCase executes one applyUserModeCase: seed
// the session state, invoke ApplyUserMode, and verify both
// the returned value and the post-call persisted state.
func runApplyUserModeCase(
	t *testing.T, testCase applyUserModeCase,
) {
	t.Helper()

	env := newTestEnv(t)
	ctx := t.Context()
	sid := createSession(ctx, t, env.db, "alice")

	seedApplyUserModeState(ctx, t, env.db, sid, testCase.initialState)

	result, err := env.svc.ApplyUserMode(
		ctx, sid, testCase.modeStr,
	)

	verifyApplyUserModeOutcome(t, testCase, result, err)
	verifyApplyUserModeState(ctx, t, env.db, sid, testCase.wantState)
}

// seedApplyUserModeState installs the pre-call session
// state described by initialState.
func seedApplyUserModeState(
	ctx context.Context,
	t *testing.T,
	database *db.Database,
	sid int64,
	initialState applyUserModeCaseState,
) {
	t.Helper()

	if initialState.oper {
		if err := database.SetSessionOper(
			ctx, sid, true,
		); err != nil {
			t.Fatalf("init oper: %v", err)
		}
	}

	if initialState.wallops {
		if err := database.SetSessionWallops(
			ctx, sid, true,
		); err != nil {
			t.Fatalf("init wallops: %v", err)
		}
	}
}

// verifyApplyUserModeOutcome asserts the direct return
// value of ApplyUserMode. It dispatches to the error- or
// success-specific verifier based on wantErr.
func verifyApplyUserModeOutcome(
	t *testing.T,
	testCase applyUserModeCase,
	result string,
	err error,
) {
	t.Helper()

	if testCase.wantErr {
		verifyApplyUserModeError(t, testCase, err)

		return
	}

	verifyApplyUserModeSuccess(t, testCase, result, err)
}

// verifyApplyUserModeError checks that err is a
// *service.IRCError whose code matches wantErrCode.
func verifyApplyUserModeError(
	t *testing.T, testCase applyUserModeCase, err error,
) {
	t.Helper()

	var ircErr *service.IRCError
	if !errors.As(err, &ircErr) {
		t.Fatalf("expected IRCError, got %v", err)
	}

	if ircErr.Code != testCase.wantErrCode {
		t.Errorf(
			"code: want %d got %d",
			testCase.wantErrCode, ircErr.Code,
		)
	}
}

// verifyApplyUserModeSuccess checks that err is nil and the
// returned mode string matches wantModes.
func verifyApplyUserModeSuccess(
	t *testing.T,
	testCase applyUserModeCase,
	result string,
	err error,
) {
	t.Helper()

	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	if result != testCase.wantModes {
		t.Errorf(
			"modes: want %q got %q",
			testCase.wantModes, result,
		)
	}
}

// verifyApplyUserModeState asserts the post-call persisted
// session state. This is the atomicity guarantee sneak
// demanded: whether the call succeeded or was rejected, the
// DB must match wantState exactly.
func verifyApplyUserModeState(
	ctx context.Context,
	t *testing.T,
	database *db.Database,
	sid int64,
	wantState applyUserModeCaseState,
) {
	t.Helper()

	gotOper, err := database.IsSessionOper(ctx, sid)
	if err != nil {
		t.Fatalf("read oper: %v", err)
	}

	gotWallops, err := database.IsSessionWallops(ctx, sid)
	if err != nil {
		t.Fatalf("read wallops: %v", err)
	}

	if gotOper != wantState.oper {
		t.Errorf(
			"oper: want %v got %v",
			wantState.oper, gotOper,
		)
	}

	if gotWallops != wantState.wallops {
		t.Errorf(
			"wallops: want %v got %v",
			wantState.wallops, gotWallops,
		)
	}
}