package dbx

import (
	"errors"
	"testing"

	"github.com/jackc/pgx/v5/pgconn"
)

func TestIsRetryable(t *testing.T) {
	tests := []struct {
		name string
		err  error
		want bool
	}{
		{"nil", nil, false},
		{"generic", errors.New("oops"), false},
		{"serialization_failure", &pgconn.PgError{Code: "40001"}, true},
		{"deadlock", &pgconn.PgError{Code: "40P01"}, true},
		{"too_many_connections", &pgconn.PgError{Code: "53300"}, true},
		{"connection_exception", &pgconn.PgError{Code: "08006"}, true},
		{"constraint_violation", &pgconn.PgError{Code: "23505"}, false},
		{"syntax_error", &pgconn.PgError{Code: "42601"}, false},
		{"connection_refused", errors.New("connection refused"), true},
		{"EOF", errors.New("unexpected EOF"), true},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if got := IsRetryable(tt.err); got != tt.want {
				t.Errorf("IsRetryable(%v) = %v, want %v", tt.err, got, tt.want)
			}
		})
	}
}

func TestIsConnectionError(t *testing.T) {
	tests := []struct {
		name string
		err  error
		want bool
	}{
		{"nil", nil, false},
		{"pg_class_08", &pgconn.PgError{Code: "08003"}, true},
		{"pg_class_23", &pgconn.PgError{Code: "23505"}, false},
		{"conn_refused", errors.New("connection refused"), true},
		{"broken_pipe", errors.New("write: broken pipe"), true},
		{"generic", errors.New("something else"), false},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if got := IsConnectionError(tt.err); got != tt.want {
				t.Errorf("IsConnectionError(%v) = %v, want %v", tt.err, got, tt.want)
			}
		})
	}
}

func TestIsConstraintViolation(t *testing.T) {
	if IsConstraintViolation(nil) {
		t.Error("expected false for nil")
	}
	if !IsConstraintViolation(&pgconn.PgError{Code: "23505"}) {
		t.Error("expected true for unique_violation")
	}
	if IsConstraintViolation(&pgconn.PgError{Code: "42601"}) {
		t.Error("expected false for syntax_error")
	}
}

func TestPgErrorCode(t *testing.T) {
	if code := PgErrorCode(errors.New("not pg")); code != "" {
		t.Errorf("expected empty, got %q", code)
	}
	if code := PgErrorCode(&pgconn.PgError{Code: "42P01"}); code != "42P01" {
		t.Errorf("expected 42P01, got %q", code)
	}
}

func TestRetryError(t *testing.T) {
	inner := errors.New("conn lost")
	err := newRetryError(3, inner)

	if !errors.Is(err, ErrRetryExhausted) {
		t.Error("should unwrap to ErrRetryExhausted")
	}
	if !errors.Is(err, inner) {
		t.Error("should unwrap to inner error")
	}
	if err.Error() == "" {
		t.Error("error string should not be empty")
	}
}