package com.hubilon.handler;

import com.hubilon.config.ConfigService;
import com.hubilon.util.DebugState;
import com.hubilon.util.HttpResponses;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;

import java.io.IOException;
import java.net.URLDecoder;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

public final class ConfigHandler implements HttpHandler {

    private final ConfigService configService;
    private final String preferredConfig;
    private final DebugState debugState;

    public ConfigHandler(ConfigService configService, String preferredConfig, DebugState debugState) {
        this.configService = configService;
        this.preferredConfig = preferredConfig;
        this.debugState = debugState;
    }

    @Override
    public void handle(HttpExchange exchange) throws IOException {
        List<String> available = configService.listConfigFiles();
        String requested = queryParam(exchange, "file");
        if (requested == null || requested.isBlank()) {
            requested = configService.resolveDefaultConfig(preferredConfig, available);
        }

        if (requested == null) {
            HttpResponses.sendJson(exchange, 500, Map.of("error", "No *.json config file found next to the jar"));
            return;
        }
        if (!available.contains(requested)) {
            Map<String, Object> payload = new LinkedHashMap<>();
            payload.put("error", "Unknown config file");
            payload.put("files", available);
            HttpResponses.sendJson(exchange, 400, payload);
            return;
        }

        try {
            Map<String, Object> doc = configService.assemble(requested);
            debugState.updateFromConfig(Boolean.TRUE.equals(doc.get("debug")), extractSecrets(doc));
            HttpResponses.sendJson(exchange, 200, doc);
        } catch (Exception e) {
            HttpResponses.sendJson(exchange, 500, Map.of("error", String.valueOf(e.getMessage())));
        }
    }

    @SuppressWarnings("unchecked")
    private static List<String> extractSecrets(Map<String, Object> doc) {
        List<String> secrets = new ArrayList<>();
        collectSecretsFromVariables(doc.get("variables"), secrets);

        Object groups = doc.get("variableGroups");
        if (groups instanceof List<?> groupList) {
            for (Object g : groupList) {
                if (g instanceof Map<?, ?> group) {
                    collectSecretsFromVariables(group.get("variables"), secrets);
                }
            }
        }
        return secrets;
    }

    private static void collectSecretsFromVariables(Object variables, List<String> secrets) {
        if (!(variables instanceof Map<?, ?> varMap)) {
            return;
        }
        for (Object v : varMap.values()) {
            if (v instanceof Map<?, ?> varDef) {
                Object isSecret = varDef.get("secret");
                Object def = varDef.get("default");
                if (Boolean.TRUE.equals(isSecret) && def != null) {
                    secrets.add(String.valueOf(def));
                }
            }
        }
    }

    private static String queryParam(HttpExchange exchange, String name) {
        String query = exchange.getRequestURI().getRawQuery();
        if (query == null) {
            return null;
        }
        for (String pair : query.split("&")) {
            int eq = pair.indexOf('=');
            String key = eq >= 0 ? pair.substring(0, eq) : pair;
            if (!key.equals(name)) {
                continue;
            }
            String value = eq >= 0 ? pair.substring(eq + 1) : "";
            try {
                return URLDecoder.decode(value, StandardCharsets.UTF_8);
            } catch (Exception e) {
                return value;
            }
        }
        return null;
    }
}