// 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)
	}
}

// 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) {
	type caseState struct {
		oper    bool
		wallops bool
	}

	// Each case starts from initialState, calls
	// ApplyUserMode(modeStr), and verifies either the
	// returned mode string (wantModes) or an IRCError with
	// wantErrCode. After the call, the DB must match
	// wantState — proving that rejected input made no
	// change.
	cases := []struct {
		name         string
		initialState caseState
		modeStr      string
		wantModes    string
		wantErr      bool
		wantErrCode  irc.IRCMessageType
		wantState    caseState
	}{
		// Happy path: single-char operations.
		{
			name:      "+w from empty",
			modeStr:   "+w",
			wantModes: "+w",
			wantState: caseState{wallops: true},
		},
		{
			name:         "-w from +w",
			initialState: caseState{wallops: true},
			modeStr:      "-w",
			wantModes:    "+",
			wantState:    caseState{},
		},
		{
			name:         "-o from +o",
			initialState: caseState{oper: true},
			modeStr:      "-o",
			wantModes:    "+",
			wantState:    caseState{},
		},
		// Multi-char without sign transitions.
		{
			name:         "-wo from +ow",
			initialState: caseState{oper: true, wallops: true},
			modeStr:      "-wo",
			wantModes:    "+",
			wantState:    caseState{},
		},
		// Multi-char with sign transitions.
		{
			name:         "+w-o from +o",
			initialState: caseState{oper: true},
			modeStr:      "+w-o",
			wantModes:    "+w",
			wantState:    caseState{wallops: true},
		},
		{
			name:         "-w+o always rejects +o",
			initialState: caseState{wallops: true, oper: true},
			modeStr:      "-w+o",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			// +o is rejected before any op applies; wallops
			// stays set.
			wantState: caseState{wallops: true, oper: true},
		},
		{
			name:         "+o-w+w rejects because of +o",
			initialState: caseState{wallops: true, oper: true},
			modeStr:      "+o-w+w",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			// Wallops must NOT be cleared; oper must NOT be
			// cleared. Rejection is fully atomic.
			wantState: caseState{wallops: true, oper: true},
		},
		{
			name:        "-x+y rejects unknown -x",
			modeStr:     "-x+y",
			wantErr:     true,
			wantErrCode: irc.ErrUmodeUnknownFlag,
			wantState:   caseState{},
		},
		{
			name:        "+y-x rejects unknown +y",
			modeStr:     "+y-x",
			wantErr:     true,
			wantErrCode: irc.ErrUmodeUnknownFlag,
			wantState:   caseState{},
		},
		// Malformed prefix — must not silently treat as '-'.
		{
			name:        "w no prefix rejects",
			modeStr:     "w",
			wantErr:     true,
			wantErrCode: irc.ErrUmodeUnknownFlag,
			wantState:   caseState{},
		},
		{
			name: "xw no prefix rejects (would have been" +
				" silently -w before)",
			initialState: caseState{wallops: true},
			modeStr:      "xw",
			wantErr:      true,
			wantErrCode:  irc.ErrUmodeUnknownFlag,
			// Prove wallops is NOT cleared — the whole point
			// of sneak's review.
			wantState: caseState{wallops: true},
		},
		{
			name:        "empty string rejects",
			modeStr:     "",
			wantErr:     true,
			wantErrCode: irc.ErrUmodeUnknownFlag,
			wantState:   caseState{},
		},
		// Bare signs with no mode letters reject.
		{
			name:        "bare + rejects",
			modeStr:     "+",
			wantErr:     true,
			wantErrCode: irc.ErrUmodeUnknownFlag,
			wantState:   caseState{},
		},
		{
			name:        "bare - rejects",
			modeStr:     "-",
			wantErr:     true,
			wantErrCode: irc.ErrUmodeUnknownFlag,
			wantState:   caseState{},
		},
		{
			name:        "+-+ rejects (no mode letters)",
			modeStr:     "+-+",
			wantErr:     true,
			wantErrCode: irc.ErrUmodeUnknownFlag,
			wantState:   caseState{},
		},
		// Unknown mode letters reject whole string.
		{
			name:        "+z unknown mode rejects",
			modeStr:     "+z",
			wantErr:     true,
			wantErrCode: irc.ErrUmodeUnknownFlag,
			wantState:   caseState{},
		},
		{
			name: "+wz rejects whole thing; +w side effect" +
				" must NOT persist",
			modeStr:     "+wz",
			wantErr:     true,
			wantErrCode: irc.ErrUmodeUnknownFlag,
			// Wallops must NOT be set.
			wantState: caseState{},
		},
		{
			name: "+wo rejects whole thing; +w side effect" +
				" must NOT persist",
			modeStr:     "+wo",
			wantErr:     true,
			wantErrCode: irc.ErrUmodeUnknownFlag,
			wantState:   caseState{},
		},
	}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			env := newTestEnv(t)
			ctx := t.Context()
			sid := createSession(ctx, t, env.db, "alice")

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

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

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

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

				if ircErr.Code != tc.wantErrCode {
					t.Errorf(
						"code: want %d got %d",
						tc.wantErrCode, ircErr.Code,
					)
				}
			} else {
				if err != nil {
					t.Fatalf("unexpected error: %v", err)
				}

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

			// Whether or not the call errored, the persisted
			// state must match wantState — this is the
			// atomicity guarantee sneak demanded.
			gotOper, err := env.db.IsSessionOper(ctx, sid)
			if err != nil {
				t.Fatalf("read oper: %v", err)
			}

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

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

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