package com.android.trisolarisserver.component

import com.fasterxml.jackson.databind.JsonNode
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 PostalPincodeClient(
    private val restTemplate: RestTemplate,
    private val objectMapper: ObjectMapper,
    @Value("\${pincode.postal.baseUrl:https://api.postalpincode.in}")
    private val baseUrl: String
) {
    private val logger = LoggerFactory.getLogger(PostalPincodeClient::class.java)

    fun resolve(pinCode: String): PincodeLookupResult {
        return try {
            val first = fetch(baseUrl, pinCode)
            if (first.resolvedCityState != null) return first
            if (first.status == "ERROR" && baseUrl.startsWith("https://")) {
                val httpUrl = baseUrl.replaceFirst("https://", "http://")
                val second = fetch(httpUrl, pinCode)
                if (second.resolvedCityState != null) return second
                return second
            }
            first
        } catch (ex: Exception) {
            logger.warn("Postalpincode lookup failed: {}", ex.message)
            PincodeLookupResult(null, null, "ERROR", "postalpincode.in", ex.message)
        }
    }

    private fun fetch(base: String, pinCode: String): PincodeLookupResult {
        val url = UriComponentsBuilder.fromUriString(base)
            .path("/pincode/{pin}")
            .buildAndExpand(pinCode)
            .toUriString()
        val response = restTemplate.getForEntity(url, String::class.java)
        val body = response.body ?: return PincodeLookupResult(null, null, "EMPTY_BODY", "postalpincode.in")
        val resolved = parseCityState(body)
        val status = if (resolved == null) "ZERO_RESULTS" else "OK"
        return PincodeLookupResult(resolved, body, status, "postalpincode.in")
    }

    private fun parseCityState(body: String): String? {
        val root = objectMapper.readTree(body)
        if (!root.isArray || root.isEmpty) return null
        val first = root.first()
        val status = first.path("Status").asText(null)
        if (!status.equals("Success", true)) return null
        val offices = first.path("PostOffice")
        if (!offices.isArray || offices.isEmpty) return null
        val office = chooseOffice(offices) ?: return null
        val district = office.path("District").asText(null)
        val state = office.path("State").asText(null)
        if (district.isNullOrBlank() && state.isNullOrBlank()) return null
        return listOfNotNull(district?.ifBlank { null }, state?.ifBlank { null }).joinToString(", ")
    }

    private fun chooseOffice(offices: JsonNode): JsonNode? {
        val delivery = offices.firstOrNull { it.path("DeliveryStatus").asText("").equals("Delivery", true) }
        return delivery ?: offices.firstOrNull()
    }
}