var RELEASE_CACHE = {};
var RELEASE_REQUESTS = {};
var RELEASE_CACHE_TTL = 15 * 60 * 1000;
var RELEASE_BACKOFF = {};
var RELEASE_MAX_RETRIES = 3;

function fetchProjectReleases(project) {
    var now = Date.now();
    var cached = RELEASE_CACHE[project];

    if (cached && now - cached.timestamp < RELEASE_CACHE_TTL) {
        return Promise.resolve(cached.data);
    }

    if (RELEASE_REQUESTS[project]) {
        return RELEASE_REQUESTS[project];
    }

    var backoff = RELEASE_BACKOFF[project];

    if (backoff && now < backoff.until) {
        return Promise.resolve(cached ? cached.data : []);
    }

    var url = "https://gitlab.com/api/v4/projects/vyla-entertainment%2F" +
        encodeURIComponent(project) + "/releases";

    var request = function (attempt) {
        return fetch(url)
            .then(function (res) {
                if (res.status === 429) {
                    var retryAfter = Number(res.headers.get("Retry-After"));
                    var delay = retryAfter > 0
                        ? retryAfter * 1000
                        : Math.min(5000 * Math.pow(2, attempt), 60000);

                    RELEASE_BACKOFF[project] = {
                        until: Date.now() + delay
                    };

                    if (attempt < RELEASE_MAX_RETRIES) {
                        return new Promise(function (resolve) {
                            setTimeout(resolve, delay);
                        }).then(function () {
                            return request(attempt + 1);
                        });
                    }

                    throw new Error("GitLab rate limit exceeded");
                }

                if (!res.ok) {
                    throw new Error("GitLab API returned " + res.status);
                }

                return res.json();
            })
            .then(function (data) {
                if (!Array.isArray(data)) {
                    throw new Error("Invalid GitLab releases response");
                }

                RELEASE_CACHE[project] = {
                    data: data,
                    timestamp: Date.now()
                };

                delete RELEASE_BACKOFF[project];

                return data;
            });
    };

    RELEASE_REQUESTS[project] = request(0)
        .catch(function () {
            return cached ? cached.data : [];
        })
        .finally(function () {
            delete RELEASE_REQUESTS[project];
        });

    return RELEASE_REQUESTS[project];
}

function findAssetInReleases(releases, ext) {
    for (var r = 0; r < releases.length; r++) {
        var rel = releases[r];
        var tag = rel.tag_name || "";
        var links = (rel.assets && rel.assets.links) || [];

        for (var i = 0; i < links.length; i++) {
            var l = links[i];
            var name = (l.name || "").toLowerCase();
            var url = (l.url || "").toLowerCase();

            if (name.indexOf(ext.toLowerCase()) !== -1 ||
                url.indexOf(ext.toLowerCase()) !== -1) {
                return {
                    tag: tag,
                    url: l.direct_asset_url || l.url
                };
            }
        }

        if (rel.description) {
            var escapedExt = ext.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");

            var reg = new RegExp(
                "\\[([^\\]]+)\\]\\((https?:[^)]+\\." + escapedExt + "[^)]*)\\)",
                "i"
            );

            var match = rel.description.match(reg);

            if (match) {
                return { tag: tag, url: match[2] };
            }

            var rawMatch = rel.description.match(
                new RegExp("(https?:\\S+\\." + escapedExt + ")", "i")
            );

            if (rawMatch) {
                return { tag: tag, url: rawMatch[1] };
            }
        }
    }

    return null;
}

function findAssetInReleases(releases, ext) {
    for (var r = 0; r < releases.length; r++) {
        var rel = releases[r];
        var tag = rel.tag_name || "";
        var links = (rel.assets && rel.assets.links) || [];
        for (var i = 0; i < links.length; i++) {
            var l = links[i];
            var name = (l.name || "").toLowerCase();
            var url = (l.url || "").toLowerCase();
            if (name.indexOf(ext) !== -1 || url.indexOf(ext) !== -1) {
                return { tag: tag, url: l.direct_asset_url || l.url };
            }
        }
        if (rel.description) {
            var reg = new RegExp("\\[([^\\]]+)\\]\\((https?:[^)]+\\." + ext + "[^)]*)\\)", "i");
            var match = rel.description.match(reg);
            if (match) return { tag: tag, url: match[2] };
            var rawMatch = rel.description.match(new RegExp("(https?:\\S+\\." + ext + ")", "i"));
            if (rawMatch) return { tag: tag, url: rawMatch[1] };
        }
    }
    return null;
}