package com.hyperling.weather

import io.ktor.client.HttpClient
import io.ktor.client.call.body
import io.ktor.client.engine.HttpClientEngine
import io.ktor.client.plugins.contentnegotiation.ContentNegotiation
import io.ktor.http.encodeURLParameter
import io.ktor.serialization.kotlinx.json.json
import kotlinx.serialization.json.Json

/**
 * Repository for fetching weather data from OpenMeteo API.
 * OpenMeteo is free and does not require an API key for basic usage.
 */
object WeatherRepository {

    private const val OPEN_METEO_URL = "https://api.open-meteo.com/v1/forecast"

    private val json = Json {
        ignoreUnknownKeys = true
        prettyPrint = false
    }

    private lateinit var httpClient: HttpClient

    fun init(engine: HttpClientEngine) {
        httpClient = HttpClient(engine) {
            install(ContentNegotiation) {
                json(json)
            }
        }
    }

    /**
     * Fetch weather data for a location by coordinates.
     * Returns the parsed OpenMeteo daily forecast response.
     */
    suspend fun fetchWeather(latitude: Double, longitude: Double): OpenMeteoResponse {
        return httpClient.get(OPEN_METEO_URL) {
            url {
                parameters.append("latitude", latitude.toString())
                parameters.append("longitude", longitude.toString())
                parameters.append("daily", "temperature_2m_max,temperature_2m_min")
                parameters.append("forecast_days", "7")
                parameters.append("timezone", "auto")
            }
        }.body()
    }

    /**
     * Parse the raw API response into our domain models.
     */
    fun parseDailyWeather(response: OpenMeteoResponse): List<DailyWeather> {
        val dates = response.daily.time ?: emptyList()
        val highs = response.daily.temperature_2m_max ?: emptyList()
        val lows = response.daily.temperature_2m_min ?: emptyList()

        return dates.mapIndexed { index, date ->
            DailyWeather(
                date = date,
                tempMaxCelsius = if (index < highs.size) highs[index] else null,
                tempMinCelsius = if (index < lows.size) lows[index] else null,
            )
        }
    }

    /**
     * Convert a location entry to weather data.
     */
    suspend fun getWeatherForLocation(location: LocationEntry): Result<LocationWeather> {
        return try {
            val response = if (location.zipCode.isNotBlank()) {
                // OpenMeteo doesn't support zip code lookup directly,
                // but we can use the lat/long which should be populated
                fetchWeather(location.latitude, location.longitude)
            } else {
                fetchWeather(location.latitude, location.longitude)
            }

            val daily = parseDailyWeather(response)

            Result.success(
                LocationWeather(
                    locationId = location.id,
                    zipCode = location.zipCode,
                    nickname = location.nickname,
                    latitude = location.latitude,
                    longitude = location.longitude,
                    dailyWeather = daily,
                    lastUpdatedMillis = System.currentTimeMillis(),
                )
            )
        } catch (e: Exception) {
            Result.failure(e)
        }
    }
}