package engine

import (
	"testing"
	"time"

	"github.com/seaweedfs/seaweedfs/weed/pb/schema_pb"
)

func TestDateTimeFunctions(t *testing.T) {
	engine := NewTestSQLEngine()

	t.Run("CURRENT_DATE function tests", func(t *testing.T) {
		result, err := engine.CurrentDate()
		if err != nil {
			t.Errorf("CurrentDate failed: %v", err)
		}

		if result == nil {
			t.Errorf("CurrentDate returned nil result")
			return
		}

		stringVal, ok := result.Kind.(*schema_pb.Value_StringValue)
		if !ok {
			t.Errorf("CurrentDate should return string value, got %T", result.Kind)
			return
		}

		// Check format (YYYY-MM-DD)
		today := time.Now().Format("2006-01-02")
		if stringVal.StringValue != today {
			t.Errorf("Expected current date %s, got %s", today, stringVal.StringValue)
		}
	})

	t.Run("CURRENT_TIMESTAMP function tests", func(t *testing.T) {
		before := time.Now()
		result, err := engine.CurrentTimestamp()
		after := time.Now()

		if err != nil {
			t.Errorf("CurrentTimestamp failed: %v", err)
		}

		if result == nil {
			t.Errorf("CurrentTimestamp returned nil result")
			return
		}

		timestampVal, ok := result.Kind.(*schema_pb.Value_TimestampValue)
		if !ok {
			t.Errorf("CurrentTimestamp should return timestamp value, got %T", result.Kind)
			return
		}

		timestamp := time.UnixMicro(timestampVal.TimestampValue.TimestampMicros)

		// Check that timestamp is within reasonable range
		if timestamp.Before(before) || timestamp.After(after) {
			t.Errorf("Timestamp %v should be between %v and %v", timestamp, before, after)
		}
	})

	t.Run("NOW function tests", func(t *testing.T) {
		result, err := engine.Now()
		if err != nil {
			t.Errorf("Now failed: %v", err)
		}

		if result == nil {
			t.Errorf("Now returned nil result")
			return
		}

		// Should return same type as CurrentTimestamp
		_, ok := result.Kind.(*schema_pb.Value_TimestampValue)
		if !ok {
			t.Errorf("Now should return timestamp value, got %T", result.Kind)
		}
	})

	t.Run("CURRENT_TIME function tests", func(t *testing.T) {
		result, err := engine.CurrentTime()
		if err != nil {
			t.Errorf("CurrentTime failed: %v", err)
		}

		if result == nil {
			t.Errorf("CurrentTime returned nil result")
			return
		}

		stringVal, ok := result.Kind.(*schema_pb.Value_StringValue)
		if !ok {
			t.Errorf("CurrentTime should return string value, got %T", result.Kind)
			return
		}

		// Check format (HH:MM:SS)
		if len(stringVal.StringValue) != 8 || stringVal.StringValue[2] != ':' || stringVal.StringValue[5] != ':' {
			t.Errorf("CurrentTime should return HH:MM:SS format, got %s", stringVal.StringValue)
		}
	})
}

func TestExtractFunction(t *testing.T) {
	engine := NewTestSQLEngine()

	// Create a test timestamp: 2023-06-15 14:30:45
	// Use local time to avoid timezone conversion issues
	testTime := time.Date(2023, 6, 15, 14, 30, 45, 0, time.Local)
	testTimestamp := &schema_pb.Value{
		Kind: &schema_pb.Value_TimestampValue{
			TimestampValue: &schema_pb.TimestampValue{
				TimestampMicros: testTime.UnixMicro(),
			},
		},
	}

	tests := []struct {
		name     string
		part     DatePart
		value    *schema_pb.Value
		expected int64
		expectErr bool
	}{
		{
			name: "Extract YEAR",
			part: PartYear,
			value: testTimestamp,
			expected: 2023,
			expectErr: false,
		},
		{
			name: "Extract MONTH",
			part: PartMonth,
			value: testTimestamp,
			expected: 6,
			expectErr: false,
		},
		{
			name: "Extract DAY",
			part: PartDay,
			value: testTimestamp,
			expected: 15,
			expectErr: false,
		},
		{
			name: "Extract HOUR",
			part: PartHour,
			value: testTimestamp,
			expected: 14,
			expectErr: false,
		},
		{
			name: "Extract MINUTE",
			part: PartMinute,
			value: testTimestamp,
			expected: 30,
			expectErr: false,
		},
		{
			name: "Extract SECOND",
			part: PartSecond,
			value: testTimestamp,
			expected: 45,
			expectErr: false,
		},
		{
			name: "Extract QUARTER from June",
			part: PartQuarter,
			value: testTimestamp,
			expected: 2, // June is in Q2
			expectErr: false,
		},
		{
			name: "Extract from string date",
			part: PartYear,
			value: &schema_pb.Value{Kind: &schema_pb.Value_StringValue{StringValue: "2023-06-15"}},
			expected: 2023,
			expectErr: false,
		},
		{
			name: "Extract from Unix timestamp",
			part: PartYear,
			value: &schema_pb.Value{Kind: &schema_pb.Value_Int64Value{Int64Value: testTime.Unix()}},
			expected: 2023,
			expectErr: false,
		},
		{
			name: "Extract from null value",
			part: PartYear,
			value: nil,
			expected: 0,
			expectErr: true,
		},
		{
			name: "Extract invalid part",
			part: DatePart("INVALID"),
			value: testTimestamp,
			expected: 0,
			expectErr: true,
		},
		{
			name: "Extract from invalid string",
			part: PartYear,
			value: &schema_pb.Value{Kind: &schema_pb.Value_StringValue{StringValue: "invalid-date"}},
			expected: 0,
			expectErr: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			result, err := engine.Extract(tt.part, tt.value)

			if tt.expectErr {
				if err == nil {
					t.Errorf("Expected error but got none")
				}
				return
			}

			if err != nil {
				t.Errorf("Unexpected error: %v", err)
				return
			}

			if result == nil {
				t.Errorf("Extract returned nil result")
				return
			}

			intVal, ok := result.Kind.(*schema_pb.Value_Int64Value)
			if !ok {
				t.Errorf("Extract should return int64 value, got %T", result.Kind)
				return
			}

			if intVal.Int64Value != tt.expected {
				t.Errorf("Expected %d, got %d", tt.expected, intVal.Int64Value)
			}
		})
	}
}

func TestDateTruncFunction(t *testing.T) {
	engine := NewTestSQLEngine()

	// Create a test timestamp: 2023-06-15 14:30:45.123456
	testTime := time.Date(2023, 6, 15, 14, 30, 45, 123456000, time.Local) // nanoseconds
	testTimestamp := &schema_pb.Value{
		Kind: &schema_pb.Value_TimestampValue{
			TimestampValue: &schema_pb.TimestampValue{
				TimestampMicros: testTime.UnixMicro(),
			},
		},
	}

	tests := []struct {
		name       string
		precision  string
		value      *schema_pb.Value
		expectErr  bool
		expectedCheck func(result time.Time) bool // Custom check function
	}{
		{
			name: "Truncate to second",
			precision: "second",
			value: testTimestamp,
			expectErr: false,
			expectedCheck: func(result time.Time) bool {
				return result.Year() == 2023 && result.Month() == 6 && result.Day() == 15 &&
					result.Hour() == 14 && result.Minute() == 30 && result.Second() == 45 &&
					result.Nanosecond() == 0
			},
		},
		{
			name: "Truncate to minute",
			precision: "minute",
			value: testTimestamp,
			expectErr: false,
			expectedCheck: func(result time.Time) bool {
				return result.Year() == 2023 && result.Month() == 6 && result.Day() == 15 &&
					result.Hour() == 14 && result.Minute() == 30 && result.Second() == 0 &&
					result.Nanosecond() == 0
			},
		},
		{
			name: "Truncate to hour",
			precision: "hour",
			value: testTimestamp,
			expectErr: false,
			expectedCheck: func(result time.Time) bool {
				return result.Year() == 2023 && result.Month() == 6 && result.Day() == 15 &&
					result.Hour() == 14 && result.Minute() == 0 && result.Second() == 0 &&
					result.Nanosecond() == 0
			},
		},
		{
			name: "Truncate to day",
			precision: "day",
			value: testTimestamp,
			expectErr: false,
			expectedCheck: func(result time.Time) bool {
				return result.Year() == 2023 && result.Month() == 6 && result.Day() == 15 &&
					result.Hour() == 0 && result.Minute() == 0 && result.Second() == 0 &&
					result.Nanosecond() == 0
			},
		},
		{
			name: "Truncate to month",
			precision: "month",
			value: testTimestamp,
			expectErr: false,
			expectedCheck: func(result time.Time) bool {
				return result.Year() == 2023 && result.Month() == 6 && result.Day() == 1 &&
					result.Hour() == 0 && result.Minute() == 0 && result.Second() == 0 &&
					result.Nanosecond() == 0
			},
		},
		{
			name: "Truncate to quarter",
			precision: "quarter",
			value: testTimestamp,
			expectErr: false,
			expectedCheck: func(result time.Time) bool {
				// June (month 6) should truncate to April (month 4) - start of Q2
				return result.Year() == 2023 && result.Month() == 4 && result.Day() == 1 &&
					result.Hour() == 0 && result.Minute() == 0 && result.Second() == 0 &&
					result.Nanosecond() == 0
			},
		},
		{
			name: "Truncate to year",
			precision: "year",
			value: testTimestamp,
			expectErr: false,
			expectedCheck: func(result time.Time) bool {
				return result.Year() == 2023 && result.Month() == 1 && result.Day() == 1 &&
					result.Hour() == 0 && result.Minute() == 0 && result.Second() == 0 &&
					result.Nanosecond() == 0
			},
		},
		{
			name: "Truncate with plural precision",
			precision: "minutes", // Test plural form
			value: testTimestamp,
			expectErr: false,
			expectedCheck: func(result time.Time) bool {
				return result.Year() == 2023 && result.Month() == 6 && result.Day() == 15 &&
					result.Hour() == 14 && result.Minute() == 30 && result.Second() == 0 &&
					result.Nanosecond() == 0
			},
		},
		{
			name: "Truncate from string date",
			precision: "day",
			value: &schema_pb.Value{Kind: &schema_pb.Value_StringValue{StringValue: "2023-06-15 14:30:45"}},
			expectErr: false,
			expectedCheck: func(result time.Time) bool {
				// The result should be the start of day 2023-06-15 in local timezone
				expectedDay := time.Date(2023, 6, 15, 0, 0, 0, 0, result.Location())
				return result.Equal(expectedDay)
			},
		},
		{
			name: "Truncate null value",
			precision: "day",
			value: nil,
			expectErr: true,
			expectedCheck: nil,
		},
		{
			name: "Invalid precision",
			precision: "invalid",
			value: testTimestamp,
			expectErr: true,
			expectedCheck: nil,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			result, err := engine.DateTrunc(tt.precision, tt.value)

			if tt.expectErr {
				if err == nil {
					t.Errorf("Expected error but got none")
				}
				return
			}

			if err != nil {
				t.Errorf("Unexpected error: %v", err)
				return
			}

			if result == nil {
				t.Errorf("DateTrunc returned nil result")
				return
			}

			timestampVal, ok := result.Kind.(*schema_pb.Value_TimestampValue)
			if !ok {
				t.Errorf("DateTrunc should return timestamp value, got %T", result.Kind)
				return
			}

			resultTime := time.UnixMicro(timestampVal.TimestampValue.TimestampMicros)

			if !tt.expectedCheck(resultTime) {
				t.Errorf("DateTrunc result check failed for precision %s, got time: %v", tt.precision, resultTime)
			}
		})
	}
}