package clocktime

import (
	"database/sql/driver"
	"encoding/json"
	"fmt"
	"io"
	"time"
)

func marshalJSONString(s string) ([]byte, error) {
	return json.Marshal(s)
}

func unmarshalJSONString(data []byte) (string, error) {
	var s string
	if err := json.Unmarshal(data, &s); err != nil {
		return "", err
	}
	return s, nil
}

// MarshalJSON encodes ClockTime as a JSON string HH:MM:SS.
func (t ClockTime) MarshalJSON() ([]byte, error) {
	return marshalJSONString(t.String())
}

// UnmarshalJSON decodes a JSON string into ClockTime.
func (t *ClockTime) UnmarshalJSON(data []byte) error {
	if string(data) == "null" {
		*t = ClockTime{}
		return nil
	}
	s, err := unmarshalJSONString(data)
	if err != nil {
		return err
	}
	parsed, err := ParseClockTime(s)
	if err != nil {
		return err
	}
	*t = parsed
	return nil
}

// MarshalText implements encoding.TextMarshaler.
func (t ClockTime) MarshalText() ([]byte, error) {
	return []byte(t.String()), nil
}

// UnmarshalText implements encoding.TextUnmarshaler.
func (t *ClockTime) UnmarshalText(text []byte) error {
	parsed, err := ParseClockTime(string(text))
	if err != nil {
		return err
	}
	*t = parsed
	return nil
}

// MarshalGQL implements gqlgen's Marshaler interface.
func (t ClockTime) MarshalGQL(w io.Writer) {
	fmt.Fprint(w, "\""+t.String()+"\"")
}

// UnmarshalGQL implements gqlgen's Unmarshaler interface.
func (t *ClockTime) UnmarshalGQL(value any) error {
	if value == nil {
		*t = ClockTime{}
		return nil
	}
	str, ok := value.(string)
	if !ok {
		return fmt.Errorf("ClockTime must be a string, got %T", value)
	}
	parsed, err := ParseClockTime(str)
	if err != nil {
		return err
	}
	*t = parsed
	return nil
}

// Value implements driver.Valuer for SQL TIME columns as HH:MM:SS bytes.
func (t ClockTime) Value() (driver.Value, error) {
	return []byte(t.String()), nil
}

// Scan implements sql.Scanner for time.Time, []byte, and string.
func (t *ClockTime) Scan(value any) error {
	if value == nil {
		*t = ClockTime{}
		return nil
	}

	switch v := value.(type) {
	case time.Time:
		*t = ClockTimeFromTime(v)
	case []byte:
		parsed, err := ParseClockTime(string(v))
		if err != nil {
			return fmt.Errorf("failed to parse ClockTime: %w", err)
		}
		*t = parsed
	case string:
		parsed, err := ParseClockTime(v)
		if err != nil {
			return fmt.Errorf("failed to parse ClockTime: %w", err)
		}
		*t = parsed
	default:
		return fmt.Errorf("ClockTime.Scan: unsupported type %T", value)
	}

	return nil
}

// MarshalJSON encodes ISODuration as a JSON ISO 8601 string.
func (d ISODuration) MarshalJSON() ([]byte, error) {
	return marshalJSONString(d.String())
}

// UnmarshalJSON decodes a JSON ISO 8601 duration string.
func (d *ISODuration) UnmarshalJSON(data []byte) error {
	if string(data) == "null" {
		*d = ISODuration(0)
		return nil
	}
	s, err := unmarshalJSONString(data)
	if err != nil {
		return err
	}
	parsed, err := ParseISODuration(s)
	if err != nil {
		return err
	}
	*d = parsed
	return nil
}

// MarshalText implements encoding.TextMarshaler.
func (d ISODuration) MarshalText() ([]byte, error) {
	return []byte(d.String()), nil
}

// UnmarshalText implements encoding.TextUnmarshaler.
func (d *ISODuration) UnmarshalText(text []byte) error {
	parsed, err := ParseISODuration(string(text))
	if err != nil {
		return err
	}
	*d = parsed
	return nil
}

// MarshalGQL implements gqlgen's Marshaler interface.
func (d ISODuration) MarshalGQL(w io.Writer) {
	fmt.Fprint(w, "\""+d.String()+"\"")
}

// UnmarshalGQL implements gqlgen's Unmarshaler interface.
func (d *ISODuration) UnmarshalGQL(value any) error {
	if value == nil {
		*d = ISODuration(0)
		return nil
	}
	s, ok := value.(string)
	if !ok {
		return fmt.Errorf("ISODuration must be a string, got %T", value)
	}
	parsed, err := ParseISODuration(s)
	if err != nil {
		return err
	}
	*d = parsed
	return nil
}

// Value stores ISODuration as nanoseconds in the database.
func (d ISODuration) Value() (driver.Value, error) {
	return int64(d), nil
}

// Scan reads ISODuration from int64 nanoseconds or an ISO 8601 string.
func (d *ISODuration) Scan(value any) error {
	if value == nil {
		*d = ISODuration(0)
		return nil
	}

	switch v := value.(type) {
	case int64:
		*d = ISODuration(v)
	case []byte:
		parsed, err := ParseISODuration(string(v))
		if err != nil {
			return err
		}
		*d = parsed
	case string:
		parsed, err := ParseISODuration(v)
		if err != nil {
			return err
		}
		*d = parsed
	default:
		return fmt.Errorf("ISODuration.Scan: unsupported type %T", value)
	}
	return nil
}