package utils

import (
	"fmt"
	"strconv"
	"strings"
	"time"
)

// Type Conversion Utilities
// These functions provide safe type conversion from interface{} to common types

// ToBool converts various types to boolean
// Supports: bool, int, int64, float64, string
// String values: "true", "false", "1", "0", "enabled", "disabled", "yes", "no", "on", "off"
// Returns false for nil or unsupported types
func ToBool(v interface{}) bool {
	if v == nil {
		return false
	}

	switch val := v.(type) {
	case bool:
		return val
	case int:
		return val != 0
	case int64:
		return val != 0
	case float64:
		return val != 0
	case string:
		// Normalize string to lowercase for case-insensitive comparison
		normalized := strings.ToLower(strings.TrimSpace(val))
		switch normalized {
		case "true", "1", "enabled", "yes", "on":
			return true
		case "false", "0", "disabled", "no", "off", "":
			return false
		default:
			return false
		}
	default:
		return false
	}
}

// ToString converts various types to string
// Supports: string, int, int64, float64, bool, time.Time, *time.Time
// time.Time is formatted using the optional timeFormat parameter
// If timeFormat is not provided, defaults to "2006-01-02 15:04:05"
// Returns empty string for nil or unsupported types
func ToString(v interface{}, timeFormat ...string) string {
	if v == nil {
		return ""
	}

	// Get time format (default or provided)
	format := "2006-01-02 15:04:05"
	if len(timeFormat) > 0 && timeFormat[0] != "" {
		format = timeFormat[0]
	}

	switch val := v.(type) {
	case string:
		return val
	case int:
		return fmt.Sprintf("%d", val)
	case int64:
		return fmt.Sprintf("%d", val)
	case float64:
		return fmt.Sprintf("%.0f", val)
	case bool:
		if val {
			return "true"
		}
		return "false"
	case time.Time:
		return val.Format(format)
	case *time.Time:
		if val != nil {
			return val.Format(format)
		}
		return ""
	default:
		return ""
	}
}

// ToInt64 converts various types to int64
// Supports: int, int64, float64, string
// Returns 0 for nil or unsupported types
func ToInt64(v interface{}) int64 {
	if v == nil {
		return 0
	}

	switch val := v.(type) {
	case int64:
		return val
	case int:
		return int64(val)
	case float64:
		return int64(val)
	case string:
		if parsed, err := strconv.ParseInt(val, 10, 64); err == nil {
			return parsed
		}
		return 0
	default:
		return 0
	}
}

// ToInt converts various types to int
// Supports: int, int64, float64, string
// Returns 0 for nil or unsupported types
func ToInt(v interface{}) int {
	if v == nil {
		return 0
	}

	switch val := v.(type) {
	case int:
		return val
	case int64:
		return int(val)
	case float64:
		return int(val)
	case string:
		if parsed, err := strconv.Atoi(val); err == nil {
			return parsed
		}
		return 0
	default:
		return 0
	}
}

// ToFloat64 converts various types to float64
// Supports: float64, int, int64, string
// Returns 0.0 for nil or unsupported types
func ToFloat64(v interface{}) float64 {
	if v == nil {
		return 0.0
	}

	switch val := v.(type) {
	case float64:
		return val
	case float32:
		return float64(val)
	case int:
		return float64(val)
	case int64:
		return float64(val)
	case string:
		if parsed, err := strconv.ParseFloat(val, 64); err == nil {
			return parsed
		}
		return 0.0
	default:
		return 0.0
	}
}

// ToTimeString converts various time types to RFC3339 string
// Supports: time.Time, string, int64 (unix timestamp)
// Returns empty string for nil or unsupported types
func ToTimeString(v interface{}) string {
	if v == nil {
		return ""
	}

	switch val := v.(type) {
	case time.Time:
		if val.IsZero() {
			return ""
		}
		return val.Format(time.RFC3339)
	case string:
		for _, format := range DBTimeFormats {
			if t, err := time.Parse(format, val); err == nil {
				return t.Format(time.RFC3339)
			}
		}
		return val
	case int64:
		// Assume unix timestamp
		if val > 0 {
			return time.Unix(val, 0).Format(time.RFC3339)
		}
		return ""
	default:
		return ""
	}
}

// GetTimeFormat returns the appropriate time format string for the given locale
// Returns format suitable for time.Format()
func GetTimeFormat(locale string) string {
	// Normalize locale to lowercase
	locale = strings.ToLower(strings.TrimSpace(locale))

	switch locale {
	case "zh-cn", "zh":
		// Chinese format: 2025年10月30日 08:57:51
		return "2006年01月02日 15:04:05"
	case "en", "en-us", "":
		// English format: October 30, 2025 08:57:51
		return "January 02, 2006 15:04:05"
	default:
		// Default ISO format
		return "2006-01-02 15:04:05"
	}
}

// NanoToTime converts a UnixNano int64 to UTC time.Time.
// Returns zero time for zero input.
func NanoToTime(ns int64) time.Time {
	if ns == 0 {
		return time.Time{}
	}
	return time.Unix(ns/1e9, ns%1e9).UTC()
}

// TimeToNano converts time.Time to UnixNano int64.
// Returns 0 for zero time.
func TimeToNano(t time.Time) int64 {
	if t.IsZero() {
		return 0
	}
	return t.UnixNano()
}

// DBTimeFormats contains all time formats recognized by database drivers (MySQL, PostgreSQL, SQLite).
// Ordered from most specific to least specific for efficient parsing.
var DBTimeFormats = []string{
	"2006-01-02 15:04:05",
	"2006-01-02 15:04:05.999999",
	"2006-01-02 15:04:05.999999-07",
	"2006-01-02 15:04:05.999999+00",
	"2006-01-02T15:04:05Z",
	"2006-01-02T15:04:05",
	"2006-01-02T15:04:05.000Z",
	time.RFC3339,
	time.RFC3339Nano,
}

// DBTimestampToUnix converts a database timestamp string (interface{}) to a Unix timestamp (int64).
// Supports MySQL DATETIME, PostgreSQL timestamptz (fractional seconds, timezone offsets),
// ISO 8601, RFC3339, and RFC3339Nano. Returns nil for nil, empty, or unparseable input.
func DBTimestampToUnix(val interface{}) interface{} {
	if val == nil {
		return nil
	}

	var dateTime string
	switch v := val.(type) {
	case string:
		dateTime = v
	case *string:
		if v == nil {
			return nil
		}
		dateTime = *v
	default:
		return nil
	}

	if dateTime == "" {
		return nil
	}

	for _, format := range DBTimeFormats {
		if t, err := time.Parse(format, dateTime); err == nil {
			return t.Unix()
		}
	}
	return nil
}

// UnixToDBTimestamp converts a Unix timestamp (int64, *int64, int, float64) to a standard
// DATETIME string "2006-01-02 15:04:05" in UTC. Compatible with MySQL, PostgreSQL, and SQLite.
// Returns nil for nil or unsupported types.
func UnixToDBTimestamp(val interface{}) interface{} {
	if val == nil {
		return nil
	}

	var unixTime int64
	switch v := val.(type) {
	case int64:
		unixTime = v
	case *int64:
		if v == nil {
			return nil
		}
		unixTime = *v
	case int:
		unixTime = int64(v)
	case float64:
		unixTime = int64(v)
	default:
		return nil
	}

	return time.Unix(unixTime, 0).UTC().Format("2006-01-02 15:04:05")
}

// ToUnixTimestamp converts any interface{} value to a Unix timestamp (int64).
// Handles numeric types directly and parses string/DB timestamp formats via DBTimestampToUnix.
// Returns nil for nil or unsupported types.
func ToUnixTimestamp(val interface{}) interface{} {
	if val == nil {
		return nil
	}

	switch v := val.(type) {
	case int64:
		return v
	case *int64:
		if v == nil {
			return nil
		}
		return *v
	case int:
		return int64(v)
	case float64:
		return int64(v)
	case string:
		return DBTimestampToUnix(v)
	case *string:
		if v == nil {
			return nil
		}
		return DBTimestampToUnix(*v)
	default:
		return nil
	}
}

// FormatTimeWithLocale formats a time value (time.Time, *time.Time, or string) using the specified format
// If the input is already a string, it will parse it first and then reformat it
// Returns empty string if the value cannot be parsed
func FormatTimeWithLocale(v interface{}, targetFormat string) string {
	if v == nil {
		return ""
	}

	var t time.Time
	var err error

	switch val := v.(type) {
	case time.Time:
		t = val
	case *time.Time:
		if val != nil {
			t = *val
		} else {
			return ""
		}
	case string:
		for _, format := range DBTimeFormats {
			t, err = time.Parse(format, val)
			if err == nil {
				break
			}
		}
		if err != nil {
			return val
		}
	default:
		// For unsupported types, try ToString first
		str := ToString(v)
		if str == "" {
			return ""
		}
		// Try parsing the string
		return FormatTimeWithLocale(str, targetFormat)
	}

	// Format with target format
	return t.Format(targetFormat)
}