package com.android.trisolarisserver.component

import com.fasterxml.jackson.databind.ObjectMapper
import org.slf4j.LoggerFactory
import org.springframework.beans.factory.annotation.Value
import org.springframework.stereotype.Component
import org.springframework.web.client.RestTemplate
import org.springframework.web.util.UriComponentsBuilder

@Component
class GoogleGeocodingClient(
    private val restTemplate: RestTemplate,
    private val objectMapper: ObjectMapper,
    @Value("\${google.maps.apiKey:}")
    private val apiKey: String,
    @Value("\${google.maps.geocode.baseUrl:https://maps.googleapis.com/maps/api/geocode/json}")
    private val baseUrl: String
) {
    private val logger = LoggerFactory.getLogger(GoogleGeocodingClient::class.java)

    fun resolveCityState(pinCode: String): GeocodeResult {
        if (apiKey.isBlank()) {
            return GeocodeResult(null, null, "NO_API_KEY")
        }
        return try {
            val url = UriComponentsBuilder.fromUriString(baseUrl)
                .queryParam("components", "postal_code:$pinCode|country:IN")
                .queryParam("region", "IN")
                .queryParam("key", apiKey)
                .toUriString()
            val primary = fetch(url)
            if (primary.status == "OK") {
                return primary
            }
            if (primary.status == "ZERO_RESULTS") {
                val fallbackUrl = UriComponentsBuilder.fromUriString(baseUrl)
                    .queryParam("address", "$pinCode India")
                    .queryParam("region", "IN")
                    .queryParam("key", apiKey)
                    .toUriString()
                val fallback = fetch(fallbackUrl)
                if (fallback.resolvedCityState != null) return fallback
                return primary
            }
            primary
        } catch (ex: Exception) {
            logger.warn("Geocoding failed: {}", ex.message)
            GeocodeResult(null, null, "ERROR")
        }
    }

    private fun fetch(url: String): GeocodeResult {
        val response = restTemplate.getForEntity(url, String::class.java)
        val body = response.body ?: return GeocodeResult(null, null, "EMPTY_BODY")
        val status = parseStatus(body)
        val parsed = if (status == "OK") parseCityState(body) else null
        return GeocodeResult(parsed, body, status ?: "UNKNOWN_STATUS")
    }

    private fun parseStatus(body: String): String? {
        return objectMapper.readTree(body).path("status").asText(null)
    }

    private fun parseCityState(body: String): String? {
        val root = objectMapper.readTree(body)
        val results = root.path("results")
        if (!results.isArray || results.isEmpty) return null
        val resultNode = results.firstOrNull { node ->
            node.path("types").any { it.asText(null) == "postal_code" }
        } ?: results.first()
        val components = resultNode.path("address_components")
        if (!components.isArray) return null

        var city: String? = null
        var admin2: String? = null
        var state: String? = null
        for (comp in components) {
            val types = comp.path("types").mapNotNull { it.asText(null) }.toSet()
            when {
                "locality" in types -> city = comp.path("long_name").asText(null) ?: city
                "postal_town" in types -> if (city == null) {
                    city = comp.path("long_name").asText(null)
                }
                "sublocality" in types -> if (city == null) {
                    city = comp.path("long_name").asText(null)
                }
                "administrative_area_level_2" in types -> admin2 = comp.path("long_name").asText(null) ?: admin2
                "administrative_area_level_1" in types -> state = comp.path("long_name").asText(null) ?: state
            }
        }
        val preferredCity = admin2?.trim()?.ifBlank { null } ?: city?.trim()?.ifBlank { null }
        if (preferredCity == null && state.isNullOrBlank()) return null
        return listOfNotNull(preferredCity, state?.trim()?.ifBlank { null }).joinToString(", ")
    }
}

data class GeocodeResult(
    val resolvedCityState: String?,
    val rawResponse: String?,
    val status: String?
)

data class PincodeLookupResult(
    val resolvedCityState: String?,
    val rawResponse: String?,
    val status: String?,
    val source: String,
    val errorMessage: String? = null,
    val requestUrl: String? = null
)