package weather

import (
	"regexp"
	"strings"
)

// NormalizeCondition converts Environment Canada’s verbose condition text
// into a consistent, title-cased string suitable for display or icon mapping.
func NormalizeCondition(raw string) string {
	raw = strings.TrimSpace(strings.ToLower(raw))
	if raw == "" {
		return "Unknown"
	}

	// Common regex cleanup patterns
	replacements := map[*regexp.Regexp]string{
		regexp.MustCompile(`(?i)snowshower|snow showers?`):           "Snow",
		regexp.MustCompile(`(?i)rainshower|rain showers?`):           "Rain",
		regexp.MustCompile(`(?i)freezing rain|ice pellets|sleet`):    "Freezing Rain",
		regexp.MustCompile(`(?i)flurries?`):                          "Light Snow",
		regexp.MustCompile(`(?i)thunderstorms?|tstorms?`):            "Thunderstorm",
		regexp.MustCompile(`(?i)drizzle`):                            "Drizzle",
		regexp.MustCompile(`(?i)fog patches?|mist|haze|smoke|ash`):   "Fog",
		regexp.MustCompile(`(?i)blowing snow|drifting snow`):         "Blowing Snow",
		regexp.MustCompile(`(?i)freezing drizzle`):                   "Freezing Drizzle",
		regexp.MustCompile(`(?i)showers? mixed with flurries?`):      "Mixed Rain/Snow",
		regexp.MustCompile(`(?i)snow mixed with rain`):               "Mixed Rain/Snow",
		regexp.MustCompile(`(?i)mainly cloudy|mostly cloudy`):        "Cloudy",
		regexp.MustCompile(`(?i)mainly sunny|mostly sunny|sunny`):    "Sunny",
		regexp.MustCompile(`(?i)partly cloudy|a few clouds`):         "Partly Cloudy",
		regexp.MustCompile(`(?i)clear|fair`):                         "Clear",
		regexp.MustCompile(`(?i)rain and snow|rain/snow`):            "Mixed Rain/Snow",
		regexp.MustCompile(`(?i)light rain`):                         "Light Rain",
		regexp.MustCompile(`(?i)heavy rain`):                         "Heavy Rain",
		regexp.MustCompile(`(?i)light snow`):                         "Light Snow",
		regexp.MustCompile(`(?i)heavy snow`):                         "Heavy Snow",
	}

	for pattern, replacement := range replacements {
		if pattern.MatchString(raw) {
			raw = pattern.ReplaceAllString(raw, replacement)
		}
	}

	// Collapse multiple spaces and ensure proper capitalization
	raw = strings.Join(strings.Fields(raw), " ")
	raw = strings.Title(raw)

	// Final normalization
	switch raw {
	case "Cloudy Periods":
		raw = "Cloudy"
	case "Mostly Cloudy":
		raw = "Cloudy"
	case "Mostly Sunny":
		raw = "Sunny"
	}

	return raw
}

// NormalizeWeatherData standardizes the Condition field in WeatherData.
func NormalizeWeatherData(data WeatherData) WeatherData {
	data.Condition = NormalizeCondition(data.Condition)
	return data
}