#include "ota_update.h"
#include "config.h"
#include <WiFi.h>
#include <WiFiClientSecure.h>
#include <HTTPClient.h>
#include <HTTPUpdate.h>
#include <ArduinoJson.h>
#include <cstdlib>
#include <cstdio>
#include <cstring>

namespace OtaUpdate {

namespace {
    // Gitea API URL constructed from config constants at runtime
    String releasesApiUrl() {
        return String("https://") + Config::GITEA_API_HOST + Config::GITEA_API_PATH;
    }

    bool parseVersion(const char* s, int& major, int& minor, int& patch) {
        major = minor = patch = 0;
        if (!s || !s[0]) return false;
        if (s[0] == 'v' || s[0] == 'V') s++;
        return sscanf(s, "%d.%d.%d", &major, &minor, &patch) == 3;
    }

    // Numeric version comparison (not string-based, so e.g. "3.10.0" > "3.9.0").
    int compareVersions(const char* a, const char* b) {
        int aMaj, aMin, aPat, bMaj, bMin, bPat;
        if (!parseVersion(a, aMaj, aMin, aPat) || !parseVersion(b, bMaj, bMin, bPat)) return 0;
        if (aMaj != bMaj) return aMaj - bMaj;
        if (aMin != bMin) return aMin - bMin;
        return aPat - bPat;
    }

    void addAuthHeader(HTTPClient& http) {
        http.addHeader("User-Agent", "EiswolfsFlightradarCYD-OTA/1.0");
        if (Config::GITEA_API_TOKEN[0]) {
            String auth = "token ";
            auth += Config::GITEA_API_TOKEN;
            http.addHeader("Authorization", auth);
        }
    }
}

CheckInfo checkForUpdate() {
    CheckInfo info;
    String url = releasesApiUrl();

    Serial.printf("[OTA] Checking for update: url=%s freeHeap=%u RSSI=%ddBm\n", url.c_str(),
                  (unsigned)ESP.getFreeHeap(), WiFi.RSSI());

    WiFiClientSecure client;
    client.setInsecure();
    client.setTimeout(8000);

    HTTPClient http;
    http.setTimeout(8000);
    if (!http.begin(client, url)) {
        Serial.println("[OTA] Check failed: http.begin() returned false.");
        return info;
    }
    addAuthHeader(http);

    int code = http.GET();
    if (code != HTTP_CODE_OK) {
        if (code < 0) {
            Serial.printf("[OTA] Check failed: HTTP error=%d (%s)\n", code,
                          HTTPClient::errorToString(code).c_str());
        } else {
            Serial.printf("[OTA] Check failed: HTTP status=%d\n", code);
        }
        http.end();
        return info;
    }
    String body = http.getString();
    http.end();

    JsonDocument doc;
    DeserializationError jsonErr = deserializeJson(doc, body);
    if (jsonErr) {
        Serial.printf("[OTA] Check failed: JSON error (%s)\n", jsonErr.c_str());
        return info;
    }

    const char* tag = doc["tag_name"] | "";
    if (!tag[0]) {
        Serial.println("[OTA] Check failed: no tag_name in release JSON.");
        return info;
    }

    strncpy(info.latestVersion, (tag[0] == 'v' || tag[0] == 'V') ? tag + 1 : tag,
            sizeof(info.latestVersion) - 1);

    // Construct download URL from the tag name using Gitea's standard
    // release asset pattern. browser_download_url from the API contains
    // the internal IP (http://192.168.0.37:3000/...) which the ESP32
    // cannot use — it needs the external proxy URL.
    String dlUrl = String("https://git.rasmusbendtsen.dk/rasmus/flyradar/releases/download/")
                 + String(tag) + "/firmware.bin";
    strncpy(info.downloadUrl, dlUrl.c_str(), sizeof(info.downloadUrl) - 1);

    Serial.printf("[OTA] Download URL: %s\n", info.downloadUrl);

    int cmp = compareVersions(info.latestVersion, Config::APP_VERSION);
    info.result = (cmp > 0) ? CheckResult::UpdateAvailable : CheckResult::UpToDate;
    Serial.printf("[OTA] Check successful: installed=v%s latest=v%s -> %s\n", Config::APP_VERSION,
                  info.latestVersion,
                  info.result == CheckResult::UpdateAvailable ? "Update available" : "already up-to-date");
    return info;
}

bool performUpdate(const char* url, void (*onProgress)(uint8_t percent)) {
    Serial.printf("[OTA] Starting: url=%s freeHeap=%u RSSI=%ddBm\n", url,
                  (unsigned)ESP.getFreeHeap(), WiFi.RSSI());

    WiFiClientSecure client;
    client.setInsecure();
    client.setTimeout(15000);

    // Use HTTPClient overload so we can add the Authorization header
    // (required for private repos even during download).
    HTTPClient http;
    if (!http.begin(client, url)) {
        Serial.println("[OTA] Failed: http.begin() returned false for download URL.");
        return false;
    }
    addAuthHeader(http);

    httpUpdate.rebootOnUpdate(false);
    httpUpdate.onProgress([onProgress](int cur, int total) {
        if (onProgress && total > 0) {
            onProgress((uint8_t)((cur * 100) / total));
        }
        static int8_t lastLoggedPercent = -1;
        if (total > 0) {
            int8_t pct = (int8_t)((cur * 100) / total);
            if (pct != lastLoggedPercent && pct % 10 == 0) {
                lastLoggedPercent = pct;
                Serial.printf("[OTA] Progress: %d%% (%d/%d bytes) freeHeap=%u\n", pct, cur, total,
                              (unsigned)ESP.getFreeHeap());
            }
        }
    });

    t_httpUpdate_return result = httpUpdate.update(http);
    http.end();

    if (result != HTTP_UPDATE_OK) {
        Serial.printf("[OTA] Failed: result=%d error=%d (%s) freeHeap=%u\n", (int)result,
                      httpUpdate.getLastError(), httpUpdate.getLastErrorString().c_str(),
                      (unsigned)ESP.getFreeHeap());
    } else {
        Serial.println("[OTA] Successfully downloaded and flashed.");
    }

    return result == HTTP_UPDATE_OK;
}

}