/*
streamer-tools OBS Camera Plugin - streamer-tools API client
Copyright (C) 2026 CyberCoveLLC <jknapp85@gmail.com>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License along
with this program. If not, see <https://www.gnu.org/licenses/>
*/

#include "stplugin/api_client.h"

#include "stplugin/json.h"

#include <utility>

namespace stplugin {

namespace {

std::string trim(const std::string &s)
{
    std::size_t begin = 0;
    std::size_t end = s.size();
    auto is_space = [](char c) { return c == ' ' || c == '\t' || c == '\r' || c == '\n'; };
    while (begin < end && is_space(s[begin]))
        ++begin;
    while (end > begin && is_space(s[end - 1]))
        --end;
    return s.substr(begin, end - begin);
}

/// Map a completed HTTP response onto the shared status codes. Returns
/// ApiStatus::Ok when the caller should go on to parse the body.
ApiStatus classify(const HttpResponse &response, std::string &message)
{
    if (!response.ok()) {
        message = response.network_error;
        return ApiStatus::NetworkError;
    }
    if (response.status >= 200 && response.status < 300)
        return ApiStatus::Ok;
    if (response.status == 404) {
        message = "unknown room slug, or the read key is wrong or has been rotated";
        return ApiStatus::NotFound;
    }
    if (response.status == 503) {
        message = "the streamer-tools server has no LiveKit credentials configured";
        return ApiStatus::Unavailable;
    }
    message = "HTTP " + std::to_string(response.status);
    return ApiStatus::HttpError;
}

std::string buildUrl(const ConnectionConfig &config, const char *suffix)
{
    return ApiClient::normalizeServerUrl(config.server_url) + "/api/obs/" +
           urlEncode(trim(config.room_slug)) + suffix + "?key=" + urlEncode(trim(config.read_key));
}

} // namespace

const char *describeApiStatus(ApiStatus status)
{
    switch (status) {
    case ApiStatus::Ok: return "ok";
    case ApiStatus::InvalidConfig: return "server URL, room slug and read key are all required";
    case ApiStatus::NetworkError: return "could not reach the streamer-tools server";
    case ApiStatus::NotFound: return "room not found, or the read key is wrong";
    case ApiStatus::Unavailable: return "server has no LiveKit configured";
    case ApiStatus::HttpError: return "unexpected response from the streamer-tools server";
    case ApiStatus::MalformedResponse: return "unreadable response from the streamer-tools server";
    }
    return "unknown error";
}

ApiClient::ApiClient(std::shared_ptr<HttpClient> http) : http_(std::move(http)) {}

std::string ApiClient::normalizeServerUrl(const std::string &raw)
{
    std::string url = trim(raw);
    if (url.empty())
        return url;

    // A bare "streamers.example.com" is what an operator will paste half the
    // time. Defaulting to https (never http) keeps the read key off the wire
    // in the clear.
    const bool has_scheme = url.compare(0, 7, "http://") == 0 || url.compare(0, 8, "https://") == 0;
    if (!has_scheme)
        url = "https://" + url;

    while (!url.empty() && url.back() == '/')
        url.pop_back();

    // "https://" with nothing after it is not a server.
    if (url == "https:/" || url == "https:" || url == "http:/" || url == "http:" ||
        url == "https://" || url == "http://")
        return std::string();

    return url;
}

std::string ApiClient::redactedUrl(const std::string &url)
{
    const std::size_t at = url.find("key=");
    if (at == std::string::npos)
        return url;
    const std::size_t value = at + 4;
    std::size_t end = url.find('&', value);
    if (end == std::string::npos)
        end = url.size();
    return url.substr(0, value) + "***" + url.substr(end);
}

SlotsResult ApiClient::fetchSlots(const ConnectionConfig &config) const
{
    SlotsResult result;
    if (!config.is_valid() || normalizeServerUrl(config.server_url).empty() || !http_) {
        result.status = ApiStatus::InvalidConfig;
        result.message = describeApiStatus(ApiStatus::InvalidConfig);
        return result;
    }

    HttpRequest request;
    request.method = "GET";
    request.url = buildUrl(config, "/slots");

    const HttpResponse response = http_->send(request);
    const ApiStatus status = classify(response, result.message);
    if (status != ApiStatus::Ok) {
        result.status = status;
        return result;
    }

    const json::Value root = json::parse(response.body);
    const json::Value &slots = root["slots"];
    if (!root.isObject() || !slots.isArray()) {
        result.status = ApiStatus::MalformedResponse;
        result.message = "expected a JSON object with a \"slots\" array";
        return result;
    }

    for (const json::Value &entry : slots.elements()) {
        // A slot without an identity is unusable -- it is what the session
        // wrapper subscribes by -- so skip it rather than surfacing a
        // dropdown row that can never connect. Anything else is best-effort:
        // a missing displayName falls back to the identity exactly as the
        // server itself does.
        const std::string identity = entry["identity"].asString();
        if (identity.empty())
            continue;
        SlotInfo slot;
        slot.identity = identity;
        slot.display_name = entry["displayName"].asString(identity);
        if (slot.display_name.empty())
            slot.display_name = identity;
        slot.live = entry["live"].asBool(false);
        result.slots.push_back(std::move(slot));
    }

    result.status = ApiStatus::Ok;
    return result;
}

TokenResult ApiClient::requestToken(const ConnectionConfig &config) const
{
    TokenResult result;
    if (!config.is_valid() || normalizeServerUrl(config.server_url).empty() || !http_) {
        result.status = ApiStatus::InvalidConfig;
        result.message = describeApiStatus(ApiStatus::InvalidConfig);
        return result;
    }

    HttpRequest request;
    request.method = "POST";
    request.url = buildUrl(config, "/token");
    request.content_type = "application/json";
    request.body = "{}";

    const HttpResponse response = http_->send(request);
    const ApiStatus status = classify(response, result.message);
    if (status != ApiStatus::Ok) {
        result.status = status;
        return result;
    }

    const json::Value root = json::parse(response.body);
    const std::string token = root["lkToken"].asString();
    const std::string ws_url = root["wsUrl"].asString();
    if (!root.isObject() || token.empty() || ws_url.empty()) {
        result.status = ApiStatus::MalformedResponse;
        result.message = "expected a JSON object with non-empty \"lkToken\" and \"wsUrl\"";
        return result;
    }

    result.lk_token = token;
    result.ws_url = ws_url;
    result.identity = root["identity"].asString();
    result.status = ApiStatus::Ok;
    return result;
}

} // namespace stplugin