package pq

import (
	"context"
	"database/sql"
	"database/sql/driver"
	"errors"
	"fmt"
	"net"
	"os"
	"reflect"
	"slices"
	"strings"
	"testing"
	"time"

	"github.com/lib/pq/internal/pqtest"
	"github.com/lib/pq/internal/pqutil"
	"github.com/lib/pq/internal/proto"
)

func TestNewConnector(t *testing.T) {
	// database/sql might not call our Open at all unless we do something with
	// the connection
	useConn := func(t *testing.T, db any) {
		t.Helper()
		switch db := db.(type) {
		default:
			t.Fatalf("unknown type: %T", db)
		case *sql.DB:
			tx, err := db.Begin()
			if err != nil {
				t.Fatal(err)
			}
			tx.Rollback()
		case driver.Conn:
			tx, err := db.Begin() //lint:ignore SA1019 x
			if err != nil {
				t.Fatal(err)
			}
			tx.Rollback()
		}
	}

	t.Run("WorksWithOpenDB", func(t *testing.T) {
		c, err := NewConnector("")
		if err != nil {
			t.Fatal(err)
		}
		db := sql.OpenDB(c)
		defer db.Close()
		useConn(t, db)
	})
	t.Run("Connect", func(t *testing.T) {
		c, err := NewConnector("")
		if err != nil {
			t.Fatal(err)
		}
		db, err := c.Connect(context.Background())
		if err != nil {
			t.Fatal(err)
		}
		defer db.Close()
		useConn(t, db)
	})
	t.Run("Driver", func(t *testing.T) {
		c, err := NewConnector("")
		if err != nil {
			t.Fatal(err)
		}
		db, err := c.Driver().Open("")
		if err != nil {
			t.Fatal(err)
		}
		defer db.Close()
		useConn(t, db)
	})
	t.Run("Environ", func(t *testing.T) {
		os.Setenv("PGPASSFILE", "/tmp/.pgpass")
		defer os.Unsetenv("PGPASSFILE")
		c, err := NewConnector("")
		if err != nil {
			t.Fatal(err)
		}
		if have := c.cfg.Passfile; have != "/tmp/.pgpass" {
			t.Fatalf("wrong option for pgassfile: %q", have)
		}
	})

	t.Run("WithConfig", func(t *testing.T) {
		cfg, err := NewConfig("")
		if err != nil {
			t.Fatal(err)
		}
		cfg.SSLMode = SSLModeDisable
		cfg.Runtime = map[string]string{"search_path": "foo"}

		c, err := NewConnectorConfig(cfg)
		if err != nil {
			t.Fatal(err)
		}
		want := fmt.Sprintf(
			`map[client_encoding:UTF8 connect_timeout:20 datestyle:ISO, MDY dbname:pqgo host:localhost port:%d search_path:foo sslmode:disable sslsni:yes user:pqgo]`,
			cfg.Port)
		if have := fmt.Sprintf("%v", c.cfg.tomap()); have != want {
			t.Errorf("\nhave: %s\nwant: %s", have, want)
		}

		// pq: unsupported startup parameter: search_path (08P01)
		pqtest.SkipPgbouncer(t)

		db := sql.OpenDB(c)
		defer db.Close()
		useConn(t, db)
	})

	t.Run("database=", func(t *testing.T) {
		want1, want2 := `pq: database "err" does not exist (3D000)`,
			`pq: database "two" does not exist (3D000)`
		if pqtest.Pgbouncer() {
			want1, want2 = `pq: no such database: err (08P01)`, `pq: no such database: two (08P01)`
		}

		// Make sure database= consistently take precedence over dbname=
		for i := 0; i < 10; i++ {
			err := pqtest.MustDB(t, "database=err").Ping()
			if err == nil || err.Error() != want1 {
				t.Errorf("wrong error:\nhave: %s\nwant: %s", err, want1)
			}
			err = pqtest.MustDB(t, "dbname=one database=two").Ping()
			if err == nil || err.Error() != want2 {
				t.Errorf("wrong error:\nhave: %s\nwant: %s", err, want2)
			}
		}
	})
}

// TODO: this can be merged with TestNewConfig, I think?
func TestParseOpts(t *testing.T) {
	tests := []struct {
		in      string
		want    map[string]string
		wantErr string
	}{
		{"dbname=hello user=goodbye", map[string]string{"dbname": "hello", "user": "goodbye"}, ""},
		{"dbname=hello user=goodbye  ", map[string]string{"dbname": "hello", "user": "goodbye"}, ""},
		{"dbname = hello user=goodbye", map[string]string{"dbname": "hello", "user": "goodbye"}, ""},
		{"dbname=hello user =goodbye", map[string]string{"dbname": "hello", "user": "goodbye"}, ""},
		{"dbname=hello user= goodbye", map[string]string{"dbname": "hello", "user": "goodbye"}, ""},
		{"host=localhost password='correct horse battery staple'", map[string]string{"host": "localhost", "password": "correct horse battery staple"}, ""},
		{"dbname=データベース password=パスワード", map[string]string{"dbname": "データベース", "password": "パスワード"}, ""},
		{"dbname=hello user=''", map[string]string{"dbname": "hello", "user": ""}, ""},
		{"user='' dbname=hello", map[string]string{"dbname": "hello", "user": ""}, ""},

		// The last option value is an empty string if there's no non-whitespace after its =
		{"dbname=hello user=   ", map[string]string{"dbname": "hello", "user": ""}, ""},

		// The parser ignores spaces after = and interprets the next set of non-whitespace characters as the value.
		{"user= password=foo", map[string]string{"user": "password=foo"}, ""},

		// Backslash escapes next char
		{`user=a\ \'\\b`, map[string]string{"user": `a '\b`}, ""},
		{`user='a \'b'`, map[string]string{"user": `a 'b`}, ""},

		// Incomplete escape
		{`user=x\`, map[string]string{}, "missing character after backslash"},

		// No '=' after the key
		{"postgre://marko@internet", map[string]string{}, `missing "="`},
		{"dbname user=goodbye", map[string]string{}, `missing "="`},
		{"user=foo blah", map[string]string{}, `missing "="`},
		{"user=foo blah   ", map[string]string{}, `missing "="`},

		// Unterminated quoted value
		{"dbname=hello user='unterminated", map[string]string{}, `unterminated quoted string`},
	}

	t.Parallel()
	for _, tt := range tests {
		t.Run("", func(t *testing.T) {
			var cfg Config
			err := cfg.fromDSN(tt.in)
			if !pqtest.ErrorContains(err, tt.wantErr) {
				t.Fatalf("wrong error\nhave: %v\nwant: %v", err, tt.wantErr)
			}
			if have := cfg.tomap(); !reflect.DeepEqual(have, tt.want) {
				t.Errorf("\nhave: %#v\nwant: %#v", have, tt.want)
			}
		})
	}
}

func TestRuntimeParameters(t *testing.T) {
	tests := []struct {
		conninfo      string
		param         string
		want          string
		wantErr       string
		skipPgbouncer bool
	}{
		{"DOESNOTEXIST=foo", "", "", "unrecognized configuration parameter", false},

		// we can only work with a specific value for these two
		{"client_encoding=SQL_ASCII", "", "", `unsupported client_encoding "SQL_ASCII": must be absent or "UTF8"`, false},
		{"datestyle='ISO, YDM'", "", "", `unsupported datestyle "ISO, YDM": must be absent or "ISO, MDY"`, false},

		// "options" should work exactly as it does in libpq
		// Skipped on pgbouncer as it errors with:
		//   pq: unsupported startup parameter in options: search_path
		{"options='-c search_path=pqgotest'", "search_path", "pqgotest", "", true},

		// pq should override client_encoding in this case
		// TODO: not set consistently with pgbouncer
		{"options='-c client_encoding=SQL_ASCII'", "client_encoding", "UTF8", "", true},

		// allow client_encoding to be set explicitly
		{"client_encoding=UTF8", "client_encoding", "UTF8", "", false},

		// test a runtime parameter not supported by libpq
		// Skipped on pgbouncer as it errors with:
		//   pq: unsupported startup parameter: work_mem
		{"work_mem='139kB'", "work_mem", "139kB", "", true},

		// test fallback_application_name
		{"application_name=foo fallback_application_name=bar", "application_name", "foo", "", false},
		{"application_name='' fallback_application_name=bar", "application_name", "", "", false},
		{"fallback_application_name=bar", "application_name", "bar", "", false},
	}

	t.Parallel()
	for _, tt := range tests {
		t.Run("", func(t *testing.T) {
			if tt.skipPgbouncer {
				pqtest.SkipPgbouncer(t)
			}
			if pqtest.Pgbouncer() && tt.wantErr == "unrecognized configuration parameter" {
				tt.wantErr = `unsupported startup parameter`
			}

			db := pqtest.MustDB(t, tt.conninfo)

			var have string
			row := db.QueryRow("select current_setting($1)", tt.param)
			err := row.Scan(&have)
			if !pqtest.ErrorContains(err, tt.wantErr) {
				t.Fatalf("wrong error\nhave: %v\nwant: %v", err, tt.wantErr)
			}
			if have != tt.want {
				t.Fatalf("\nhave: %v\nwant: %v", have, tt.want)
			}
		})
	}
}

// TODO: this can be merged with TestNewConfig, I think?
func TestParseEnviron(t *testing.T) {
	tests := []struct {
		in   []string
		want map[string]string
	}{
		{[]string{"PGDATABASE=hello", "PGUSER=goodbye"},
			map[string]string{"dbname": "hello", "user": "goodbye"}},
		{[]string{"PGDATESTYLE=ISO, MDY"},
			map[string]string{"datestyle": "ISO, MDY"}},
		{[]string{"PGCONNECT_TIMEOUT=30"},
			map[string]string{"connect_timeout": "30"}},
	}

	t.Parallel()
	for _, tt := range tests {
		t.Run("", func(t *testing.T) {
			var cfg Config
			err := cfg.fromEnv(tt.in)
			if err != nil {
				t.Fatal(err)
			}
			have := cfg.tomap()
			if !reflect.DeepEqual(tt.want, have) {
				t.Errorf("\nwant: %#v\nhave: %#v", tt.want, have)
			}
		})
	}
}

func TestIsUTF8(t *testing.T) {
	tests := []struct {
		name string
		want bool
	}{
		{"unicode", true},
		{"utf-8", true},
		{"utf_8", true},
		{"UTF-8", true},
		{"UTF8", true},
		{"utf8", true},
		{"u n ic_ode", true},
		{"ut_f%8", true},
		{"ubf8", false},
		{"punycode", false},
	}

	t.Parallel()
	for _, tt := range tests {
		t.Run("", func(t *testing.T) {
			have := isUTF8(tt.name)
			if have != tt.want {
				t.Errorf("\nhave: %v\nwant: %v", have, tt.want)
			}
		})
	}
}

func TestParseURL(t *testing.T) {
	tests := []struct {
		in, want, wantErr string
	}{
		{"postgres://", "", ""},
		{"postgres://hostname.remote", "host='hostname.remote'", ""},
		{"postgres://[::1]:1234", "host='::1' port='1234'", ""},
		{"postgres://username:top%20secret@hostname.remote:1234/database",
			`dbname='database' host='hostname.remote' password='top secret' port='1234' user='username'`, ""},
		{"postgres://localhost/a%2Fb", "dbname='a/b' host='localhost'", ""},

		{"", "", "invalid connection protocol:"},
		{"http://hostname.remote", "", "invalid connection protocol: http"},

		{"postgresql://%2Fvar%2Flib%2Fpostgresql/dbname", "", `invalid URL escape "%2F"`},
	}

	t.Parallel()
	for _, tt := range tests {
		t.Run("", func(t *testing.T) {
			have, err := ParseURL(tt.in)
			if !pqtest.ErrorContains(err, tt.wantErr) {
				t.Fatal(err)
			}
			if have != tt.want {
				t.Errorf("\nhave: %q\nwant: %q", have, tt.want)
			}
		})
	}
}

func TestNewConfig(t *testing.T) {
	tests := []struct {
		inDSN   string
		inEnv   []string
		want    string
		wantErr string
	}{
		// Override defaults
		{"", nil, "", ""},
		{"user=u port=1 host=example.com", nil,
			"host=example.com port=1 user=u", ""},
		{"", []string{"PGUSER=u", "PGPORT=1", "PGHOST=example.com"},
			"host=example.com port=1 user=u", ""},

		// Socket
		{"host=/var/run/psql", nil, "host=/var/run/psql sslmode=disable", ""},
		{"host=@/var/run/psql", nil, "host=@/var/run/psql sslmode=disable", ""},
		{"host=/var/run/psql sslmode=require", nil, "host=/var/run/psql sslmode=disable", ""},

		// Empty value, value with space, and value with escaped \'
		{"user=''", nil, "user=''", ""},
		{`user='with\' space'`, nil, `user='with\' space'`, ""},

		// Bool
		{"sslsni=0", nil, "sslsni=no", ""},
		{"sslsni=1", nil, "sslsni=yes", ""},
		{"sslinline=yes", nil, "sslinline=yes", ""},
		{"sslinline=no", nil, "sslinline=no", ""},
		{"sslinline=lol", nil, "", `pq: wrong value for "sslinline": strconv.ParseBool: parsing "lol": invalid syntax`},

		// application_name and fallback_application_name
		{"application_name=acme", nil, "application_name=acme", ""},
		{"application_name=acme fallback_application_name=roadrunner", nil, "application_name=acme fallback_application_name=roadrunner", ""},
		{"fallback_application_name=roadrunner", []string{"PGAPPNAME=acme"}, "application_name=acme fallback_application_name=roadrunner", ""},
		{"fallback_application_name=roadrunner", nil, "application_name=roadrunner fallback_application_name=roadrunner", ""},

		// Timeout and port
		{"connect_timeout=5", nil, "connect_timeout=5", ""},
		{"", []string{"PGCONNECT_TIMEOUT=5"}, "connect_timeout=5", ""},
		{"connect_timeout=5s", nil, "", `pq: wrong value for "connect_timeout": strconv.ParseInt: parsing "5s": invalid syntax`},
		{"", []string{"PGCONNECT_TIMEOUT=5s"}, "", `pq: wrong value for $PGCONNECT_TIMEOUT: strconv.ParseInt: parsing "5s": invalid syntax`},
		{"port=5s", nil, "", `pq: wrong value for "port": strconv.ParseUint: parsing "5s": invalid syntax`},
		{"", []string{"PGPORT=5s"}, "", `pq: wrong value for $PGPORT: strconv.ParseUint: parsing "5s": invalid syntax`},
		{"host=a,b port=1,a", nil, "", `strconv.ParseUint: parsing "a": invalid syntax`},

		// hostaddr
		{"hostaddr=127.1.2.3", nil, "hostaddr=127.1.2.3", ""},
		{"hostaddr=::1", nil, "hostaddr=::1", ""},
		{"", []string{"PGHOSTADDR=2a01:4f9:3081:5413::2"}, "hostaddr=2a01:4f9:3081:5413::2", ""},
		{"", []string{"PGHOSTADDR=lol"}, "", "unable to parse IP"},
		{"hostaddr=1.1.1.1,lol", nil, "", "unable to parse IP"},

		// Runtime
		{"user=u search_path=abc", nil, "search_path=abc user=u", ""},
		{"database=db", nil, "dbname=db", ``},

		// URL
		{"postgres://u@example.com:1/db", nil,
			"dbname=db host=example.com port=1 user=u", ""},
		{"postgres://u:pw@example.com:1/db?opt=val&sslmode=require", nil,
			"dbname=db host=example.com opt=val password=pw port=1 sslmode=require user=u", ""},
		{"postgres://pqgo@localhost/pqgo?hostaddr=1.1.1.1", nil, "dbname=pqgo host=localhost hostaddr=1.1.1.1 user=pqgo", ""},

		{"postgres://pqgo@a,,b:1/pqgo?hostaddr=1.1.1.1,,2.2.2.2", nil,
			"dbname=pqgo host=a,localhost,b hostaddr=1.1.1.1,,2.2.2.2 port=1 user=pqgo", ""},
		// net/url doesn't support multiple ports, but can use ?port= (libpq
		// also supports this).
		{"postgres://pqgo@a,b:1,2/pqgo", nil, "", "invalid port"},
		{"postgres://pqgo@a,b/pqgo?port=1,2", nil, "dbname=pqgo host=a,b port=1,2 user=pqgo", ""},

		// Unsupported env vars
		{"", []string{"PGREALM=abc"}, "", `pq: environment variable $PGREALM is not supported`},
		{"", []string{"PGKRBSRVNAME=abc"}, "", `pq: environment variable $PGKRBSRVNAME is not supported`},

		// Unsupported enums
		{"sslmode=sslmeharder", nil, "", `pq: wrong value for "sslmode"`},
		{"postgres://u:pw@example.com:1/db?sslmode=sslmeharder", nil, "", `pq: wrong value for "sslmode"`},
		{"", []string{"PGSSLMODE=sslmeharder"}, "", `pq: wrong value for $PGSSLMODE`},
		{"sslnegotiation=sslmeharder", nil, "", `pq: wrong value for "sslnegotiation"`},
		{"postgres://u:pw@example.com:1/db?sslnegotiation=sslmeharder", nil, "", `pq: wrong value for "sslnegotiation"`},
		{"", []string{"PGSSLNEGOTIATION=sslmeharder"}, "", `pq: wrong value for $PGSSLNEGOTIATION`},

		// multihost
		{"host=a,b", nil, "host=a,b", ""},
		{"host=a,b port=1,2", nil, "host=a,b port=1,2", ""},
		{"", []string{"PGHOST=a,b"}, "host=a,b", ""},
		{"hostaddr=127.2.2.2,127.3.3.3", nil, "hostaddr=127.2.2.2,127.3.3.3", ""},
		// Fill in defaults
		{"host=a,,b port=1,,2", nil, "host=a,localhost,b port=1,5432,2", ""},
		{"host=a,,c hostaddr=1.1.1.1,,2.2.2.2", nil, "host=a,localhost,c hostaddr=1.1.1.1,,2.2.2.2", ""},
		// Must have either one port or match number of hosts
		{"host=a,,b port=1", nil, "host=a,localhost,b port=1", ""},
		{"host=a,,b port=1,2", nil, "", "could not match 2 port numbers to 3 hosts"},
		{"host=a,,b port=1,2,,4", nil, "", "could not match 4 port numbers to 3 hosts"},
		// host and hostaddr must match
		{"host=a,b,c hostaddr=1.1.1.1,2.2.2.2", nil, "", "could not match 3 host names to 2 hostaddr values"},
		{"host=a hostaddr=1.1.1.1,2.2.2.2", nil, "", "could not match 1 host names to 2 hostaddr values"},
		{"", []string{"PGHOST=a,,b", "PGHOSTADDR=1.1.1.1,,2.2.2.2", "PGPORT=3,,4"}, "host=a,localhost,b hostaddr=1.1.1.1,,2.2.2.2 port=3,5432,4", ""},
	}

	t.Parallel()
	for _, tt := range tests {
		t.Run("", func(t *testing.T) {
			have, err := newConfig(tt.inDSN, tt.inEnv)
			if !pqtest.ErrorContains(err, tt.wantErr) {
				t.Fatalf("wrong error\nhave: %v\nwant: %v", err, tt.wantErr)
			}
			if have.string() != tt.want {
				t.Errorf("\nhave: %q\nwant: %q", have.string(), tt.want)
			}
		})
	}

	// Make sure connect_timeout is parsed as seconds.
	t.Run("connect_timeout", func(t *testing.T) {
		{
			have, err := newConfig("connect_timeout=3", []string{})
			if err != nil {
				t.Fatal(err)
			}
			if have.ConnectTimeout != 3*time.Second {
				t.Errorf("\nhave: %q\nwant: %q", have.ConnectTimeout, 3*time.Second)
			}
		}
		{
			have, err := newConfig("", []string{"PGCONNECT_TIMEOUT=4"})
			if err != nil {
				t.Fatal(err)
			}
			if have.ConnectTimeout != 4*time.Second {
				t.Errorf("\nhave: %q\nwant: %q", have.ConnectTimeout, 4*time.Second)
			}
		}
	})
}

func TestConfigClone(t *testing.T) {
	c := Config{
		Host:    "abc",
		Port:    5432,
		Runtime: map[string]string{"search_path": "def"},
		set:     []string{"host", "search_path", "port"},
	}
	cc := c.Clone()
	c.Host = "NEW"
	c.Runtime["search_path"] = "NEW"
	c.set[2] = "NEW"

	{
		want := `host=NEW search_path=NEW`
		if have := c.string(); have != want {
			t.Errorf("\nhave: %q\nwant: %q", have, want)
		}
	}
	{
		want := `host=abc port=5432 search_path=def`
		if have := cc.string(); have != want {
			t.Errorf("\nhave: %q\nwant: %q", have, want)
		}
	}
}

func TestConnectMulti(t *testing.T) {
	var (
		connectedTo [3]bool
		accept      = func(n int) func(pqtest.Fake, net.Conn) {
			return func(f pqtest.Fake, cn net.Conn) {
				clientParams, ok := f.ReadStartup(cn)
				if !ok {
					return
				}
				if clientParams["database"] != "pqgo" {
					f.WriteMsg(cn, proto.ErrorResponse, fmt.Sprintf(
						"SFATAL\x00VFATAL\x00C3D000\x00Mdatabase %q does not exist\x00Fpostinit.c\x00L1014\x00RInitPostgres\x00\x00",
						clientParams["database"]))
					return
				}
				f.WriteMsg(cn, proto.AuthenticationRequest, "\x00\x00\x00\x00")
				serverParams := map[string]string{
					"default_transaction_read_only": "off",
					"in_hot_standby":                "off",
				}
				if n == 2 {
					serverParams["default_transaction_read_only"] = "on"
					serverParams["in_hot_standby"] = "on"
				}
				f.WriteStartup(cn, serverParams)

				f.WriteMsg(cn, proto.ReadyForQuery, "I")
				for {
					code, _, ok := f.ReadMsg(cn)
					if !ok {
						return
					}
					switch code {
					case proto.Query:
						connectedTo[n] = true
						f.WriteMsg(cn, proto.EmptyQueryResponse, "")
						f.WriteMsg(cn, proto.ReadyForQuery, "I")
					case proto.Terminate:
						cn.Close()
						return
					}
				}
			}
		}
		f1 = pqtest.NewFake(t, accept(0))
		f2 = pqtest.NewFake(t, accept(1))
		f3 = pqtest.NewFake(t, accept(2))
	)
	defer f1.Close()
	defer f2.Close()
	defer f3.Close()

	// The host from the test servers is always 127.0.0.1. Can't reliably use
	// anything else AFAIK, as macOS only routes 127.0.0.1 instead of 127/8 like
	// it should so then the tests will work on Linux but not macOS. One of many
	// reasons macOS is wank. At any rate, make sure to add the port or you'll
	// accidentally connect to the Docker container.
	//
	// TestNewConfig() already test if everything is parsed correctly, so don't
	// need to extensively test that here.
	tests := []struct {
		dsn     string
		want    [3]bool
		wantErr []string
	}{
		{fmt.Sprintf(`host=%s,%s port=%s`, f1.Host(), f2.Host(), f1.Port()), [3]bool{true, false, false}, nil},
		{fmt.Sprintf(`host=255.255.255.255,%s port=%s`, f2.Host(), f2.Port()), [3]bool{false, true, false}, nil},
		{fmt.Sprintf(`host=wrong,wrong hostaddr=255.255.255.255,%s port=%s`, f2.Host(), f2.Port()), [3]bool{false, true, false}, nil},

		// Make sure it returns both errors.
		{fmt.Sprintf(`host=255.255.255.255,%s port=%s dbname=wrong`, f1.Host(), f1.Port()),
			[3]bool{false, false, false}, []string{"dial tcp", `database "wrong" does not exist`}},

		// Test target_session_attrs; f3 is a read-only standby server

		// any: just connect to the first one.
		{fmt.Sprintf("host=%s,%s port=%s,%s", f3.Host(), f1.Host(), f3.Port(), f1.Port()),
			[3]bool{false, false, true}, nil},
		// read-only, and standby: skip f1 and select f3
		{fmt.Sprintf("host=%s,%s port=%s,%s target_session_attrs=read-only", f1.Host(), f3.Host(), f1.Port(), f3.Port()),
			[3]bool{false, false, true}, nil},
		{fmt.Sprintf("host=%s,%s port=%s,%s target_session_attrs=standby", f1.Host(), f3.Host(), f1.Port(), f3.Port()),
			[3]bool{false, false, true}, nil},
		// read-write and primary: skip f3 and select f1
		{fmt.Sprintf("host=%s,%s port=%s,%s target_session_attrs=read-write", f3.Host(), f1.Host(), f3.Port(), f1.Port()),
			[3]bool{true, false, false}, nil},
		{fmt.Sprintf("host=%s,%s port=%s,%s target_session_attrs=primary", f3.Host(), f1.Host(), f3.Port(), f1.Port()),
			[3]bool{true, false, false}, nil},
		// prefer-standby
		{fmt.Sprintf("host=%s,%s port=%s,%s target_session_attrs=standby", f3.Host(), f3.Host(), f3.Port(), f3.Port()),
			[3]bool{false, false, true}, nil},
	}

	t.Parallel()
	for _, tt := range tests {
		t.Run("", func(t *testing.T) {
			connectedTo = [3]bool{}

			db := pqtest.MustDB(t, "connect_timeout=1 "+tt.dsn)
			err := db.Ping()
			if err != nil {
				if tt.wantErr == nil {
					t.Fatal(err)
				}

				jerr, ok := errors.Unwrap(err).(interface {
					Unwrap() []error
				})
				if !ok {
					t.Fatalf("Unwrap() []error missing on %T: %[1]s", err)
				}
				errs := jerr.Unwrap()
				if len(errs) != len(tt.wantErr) {
					t.Fatalf("wrong number of errors: %d", len(errs))
				}
				for i, e := range errs {
					if !pqtest.ErrorContains(e, tt.wantErr[i]) {
						t.Errorf("error %d wrong\nhave: %v\nwant: %v", i+1, e, tt.wantErr[i])
					}
				}
				if t.Failed() {
					t.FailNow()
				}
			}

			if !reflect.DeepEqual(connectedTo, tt.want) {
				t.Errorf("\nhave: %v\nwant: %v", connectedTo, tt.want)
			}
		})
	}

	t.Run("load_balance_hosts=random", func(t *testing.T) {
		hosts := [3]int{}
		for i := 0; i < 25; i++ {
			connectedTo = [3]bool{}
			db := pqtest.MustDB(t, fmt.Sprintf(
				"host=%s,%s,%s port=%s,%s,%s load_balance_hosts=random", f1.Host(), f2.Host(), f3.Host(), f1.Port(), f2.Port(), f3.Port(),
			))
			err := db.Ping()
			if err != nil {
				t.Fatal(err)
			}
			if n := strings.Count(fmt.Sprintf("%v", connectedTo), "true"); n != 1 {
				t.Fatal(connectedTo)
			}

			hosts[slices.Index(connectedTo[:], true)]++
		}
		if slices.Index(hosts[:], 0) != -1 {
			t.Fatal(hosts)
		}
	})
}

func TestConnectionTargetSessionAttrs(t *testing.T) {
	tests := []struct {
		dsn     string
		wantErr string
		params  map[string]string
	}{
		// read-only/read-write from server params
		{"target_session_attrs=read-only", "", map[string]string{"default_transaction_read_only": "on"}},
		{"target_session_attrs=read-write", "", map[string]string{"default_transaction_read_only": "off", "in_hot_standby": "off"}},
		{"target_session_attrs=read-only", "session is not read-only", map[string]string{"default_transaction_read_only": "off"}},
		{"target_session_attrs=read-write", "session is read-only", map[string]string{"default_transaction_read_only": "on"}},
		{"target_session_attrs=read-write", "server is in hot standby mode", map[string]string{"default_transaction_read_only": "off", "in_hot_standby": "on"}},

		// primary / standby / prefer-standby from server params
		{"target_session_attrs=primary", "", map[string]string{"in_hot_standby": "off"}},
		{"target_session_attrs=standby", "", map[string]string{"in_hot_standby": "on"}},
		{"target_session_attrs=primary", "server is in hot standby mode", map[string]string{"in_hot_standby": "on"}},
		{"target_session_attrs=standby", "server is not in hot standby mode", map[string]string{"in_hot_standby": "off"}},
		{"target_session_attrs=prefer-standby", "", map[string]string{"in_hot_standby": "on"}},
		{"target_session_attrs=prefer-standby", "", map[string]string{"in_hot_standby": "off"}},

		// read-only/read-write from SHOW
		{"target_session_attrs=read-only", "", map[string]string{"default_transaction_read_only": "show-on"}},
		{"target_session_attrs=read-write", "", map[string]string{"default_transaction_read_only": "show-off"}},
		{"target_session_attrs=read-only", "session is not read-only", map[string]string{"default_transaction_read_only": "show-off"}},
		{"target_session_attrs=read-write", "session is read-only", map[string]string{"default_transaction_read_only": "show-on"}},

		// primary / standby / prefer-standby from pg_is_in_recovery()
		{"target_session_attrs=primary", "", map[string]string{"in_hot_standby": "select-off"}},
		{"target_session_attrs=standby", "", map[string]string{"in_hot_standby": "select-on"}},
		{"target_session_attrs=primary", "server is in hot standby mode", map[string]string{"in_hot_standby": "select-on"}},
		{"target_session_attrs=standby", "server is not in hot standby mode", map[string]string{"in_hot_standby": "select-off"}},
		{"target_session_attrs=prefer-standby", "", map[string]string{"in_hot_standby": "select-on"}},
		{"target_session_attrs=prefer-standby", "", map[string]string{"in_hot_standby": "select-off"}},
	}

	for _, tt := range tests {
		tt := tt
		t.Run("", func(t *testing.T) {
			t.Parallel()

			var (
				show  string
				inrec *bool
			)
			if v := tt.params["default_transaction_read_only"]; strings.HasPrefix(v, "show-") {
				delete(tt.params, "default_transaction_read_only")
				show = v[5:]
			}
			if v := tt.params["in_hot_standby"]; strings.HasPrefix(v, "select-") {
				delete(tt.params, "in_hot_standby")
				b, err := pqutil.ParseBool(v[7:])
				if err != nil {
					t.Fatal(err)
				}
				inrec = &b
			}

			f := pqtest.NewFake(t, func(f pqtest.Fake, cn net.Conn) {
				f.Startup(cn, tt.params)
				for {
					code, _, ok := f.ReadMsg(cn)
					if !ok {
						return
					}
					switch code {
					case proto.Query:
						if show != "" {
							f.SimpleQuery(cn, "SHOW", "transaction_read_only", show)
						} else if inrec != nil {
							f.SimpleQuery(cn, "SELECT", "pg_is_in_recovery", *inrec)
						}
						f.WriteMsg(cn, proto.ReadyForQuery, "I")
					case proto.Terminate:
						cn.Close()
						return
					}
				}
			})
			defer f.Close()

			db := pqtest.MustDB(t, f.DSN()+" "+tt.dsn)

			err := db.Ping()
			if !pqtest.ErrorContains(err, tt.wantErr) {
				t.Errorf("\nhave: %v\nwant: %v", err, tt.wantErr)
			}
		})
	}
}