document.addEventListener("DOMContentLoaded", function () {
    const apiBase = "/api";

    function isTokenExpired(token) {
        try {
            const payload = JSON.parse(atob(token.split('.')[1]));
            const now = Math.floor(Date.now() / 1000);
            return payload.exp ? now >= payload.exp : false;
        } catch {
            return true;
        }
    }

    function getTokenExpirySeconds(token) {
        try {
            const payload = JSON.parse(atob(token.split('.')[1]));
            const now = Math.floor(Date.now() / 1000);
            return payload.exp ? payload.exp - now : 0;
        } catch {
            return 0;
        }
    }

    function redirectToLogin() {
        localStorage.removeItem("token");
        localStorage.removeItem("user");
        if (!window.location.pathname.startsWith("/login")) {
            window.location.href = "/login?expired=1";
        }
    }

    async function apiFetch(endpoint, options = {}) {
        const token = localStorage.getItem("token");
        if (token && isTokenExpired(token)) {
            redirectToLogin();
            throw new Error("Session expired");
        }
        const headers = {
            "Content-Type": "application/json",
            ...options.headers,
        };
        if (token) {
            headers["Authorization"] = `Bearer ${token}`;
        }
        const response = await fetch(`${apiBase}${endpoint}`, {
            ...options,
            headers,
        });
        if (response.status === 401) {
            redirectToLogin();
            throw new Error("Authentication required");
        }
        if (!response.ok) {
            let errorMsg = `HTTP ${response.status}`;
            try {
                const error = await response.json();
                if (typeof error.detail === 'string') {
                    errorMsg = error.detail;
                } else if (Array.isArray(error.detail)) {
                    errorMsg = error.detail.map(d => d.msg || d).join(', ');
                } else if (error.detail && typeof error.detail === 'object') {
                    errorMsg = error.detail.detail || error.detail.msg || JSON.stringify(error.detail);
                }
            } catch {
                // ignore parse error, use default
            }
            throw new Error(errorMsg);
        }
        return response.json();
    }

    window.LinkSync = {
        apiFetch,
        isTokenExpired,
        getTokenExpirySeconds,
        async getLinks(params = {}) {
            const qs = new URLSearchParams(params).toString();
            return apiFetch(`/links/?${qs}`);
        },
        async createLink(data) {
            return apiFetch("/links/", {
                method: "POST",
                body: JSON.stringify(data),
            });
        },
        async updateLink(id, data) {
            return apiFetch(`/links/${id}`, {
                method: "PUT",
                body: JSON.stringify(data),
            });
        },
        async deleteLink(id) {
            return apiFetch(`/links/${id}`, { method: "DELETE" });
        },
        async getCollections() {
            return apiFetch("/collections/");
        },
        async createCollection(data) {
            return apiFetch("/collections/", {
                method: "POST",
                body: JSON.stringify(data),
            });
        },
        async updateCollection(id, data) {
            return apiFetch(`/collections/${id}`, {
                method: "PUT",
                body: JSON.stringify(data),
            });
        },
        async deleteCollection(id) {
            return apiFetch(`/collections/${id}`, { method: "DELETE" });
        },
        async previewQuery(expression) {
            return apiFetch(`/queries/preview?expression=${encodeURIComponent(expression)}`);
        },
        async executeQuery(expression, limit = 20) {
            return apiFetch(`/queries/execute?expression=${encodeURIComponent(expression)}&limit=${limit}`);
        },
        async login(username, password) {
            const formData = new URLSearchParams();
            formData.append("username", username);
            formData.append("password", password);
            const response = await fetch(`${apiBase}/auth/login`, {
                method: "POST",
                headers: { "Content-Type": "application/x-www-form-urlencoded" },
                body: formData.toString(),
            });
            if (!response.ok) throw new Error("Login failed");
            const data = await response.json();
            localStorage.setItem("token", data.access_token);
            return data;
        },
        async getMe() {
            return apiFetch("/auth/me");
        },
        logout() {
            localStorage.removeItem("token");
            localStorage.removeItem("user");
            window.location.href = "/login";
        },
        async getUsers() {
            return apiFetch("/admin/users");
        },
        async createUser(data) {
            return apiFetch("/admin/users", {
                method: "POST",
                body: JSON.stringify(data),
            });
        },
        async updateUser(id, data) {
            return apiFetch(`/admin/users/${id}`, {
                method: "PUT",
                body: JSON.stringify(data),
            });
        },
        async deleteUser(id) {
            return apiFetch(`/admin/users/${id}`, { method: "DELETE" });
        },
        async getApiKeys() {
            return apiFetch("/auth/api-keys");
        },
        async createApiKey(name) {
            return apiFetch(`/auth/api-key?name=${encodeURIComponent(name)}`, {
                method: "POST",
            });
        },
        async deleteApiKey(id) {
            return apiFetch(`/auth/api-key/${id}`, { method: "DELETE" });
        },
    };
});