async function loadData (block) {
    const source = block.dataset.source;
    block.classList.remove ("loaded");
    try {
        const response = await fetch (source);
        if (response.ok) {
            const items = await response.json();

            if (Array.isArray (items)) {
                const template = block.querySelector ("template");
                const tableBody = block.querySelector ("table tbody");
                tableBody.innerHTML = "";
                items.forEach (item => {
                    const clone = template.content.cloneNode (true);
                    window["populate" + block.dataset.item] (clone, item);
                    tableBody.appendChild (clone);
                    tableBody.lastElementChild.dataset.itemid = item.id;
                });
            } else {
                window["populate" + block.dataset.item] (block, items);
            }

            block.classList.add ("loaded");
        } else {
            if ((response.status == 401) || (response.status == 403)) {
                document.location.href = document.body.dataset.baseurl;
            } else {
                block.classList.add ("failed");
            }
        }
    } catch (error) {
        block.classList.add ("failed");
    }
}

function populateUser (row, user) {
    row.querySelector (".email").innerText = user.email;
    row.querySelector (".fullname").innerText = user.fullName;
    row.querySelector (".roles").innerText = user.roles.join (", ");
    row.querySelector (".active").innerText = user.isActive ? "✓" : "";
}

async function displayUser (container, dialog, userUrl) {
    dialog.querySelectorAll (".error")
        .forEach (element => {
            element.hidden = true;
        });
    const response = await fetch (userUrl);
    if (response.ok) {
        const user = await response.json();
        dialog.querySelector ("input[name=userid]").value = user.id;
        dialog.querySelector ("input[name=email]").value = user.email;
        dialog.querySelector ("input[name=fullname]").value = user.fullName;
        dialog.querySelector ("input[name=active]").checked = user.isActive;
        dialog.querySelectorAll ("input.role")
            .forEach (checkbox => {
                checkbox.checked = user.roles.includes (checkbox.value);
            });

        container.classList.add ("loaded");
    } else {
        if ((response.status == 401) || (response.status == 403)) {
            document.location.href = document.body.dataset.baseurl;
        } else {
            container.classList.add ("failed");
        }
    }
}

function emptyUser (dialog) {
    dialog.querySelector ("input[name=email]").value = null;
    dialog.querySelector ("input[name=fullname]").value = null;
    dialog.querySelectorAll ("input[name=role]")
        .forEach (checkbox => {
            checkbox.checked = false;
        });
    dialog.querySelectorAll (".error")
        .forEach (element => {
            element.hidden = true;
        });
    dialog.querySelector ("button.invite").disabled = false;
}

function selectUser (event) {
    const row = event.target.closest ("tbody tr");

    if (row && this.contains (row)) {
        const dialog = document.querySelector (this.dataset.dialog);

        window["display" + this.dataset.item] (this, dialog, this.dataset.source + "/" + row.dataset.itemid);
        dialog.showModal();
        dialog.querySelector ("input[name=email]").focus();
    } else if (event.target.classList.contains ("new")) {
        const dialog = document.querySelector (event.target.dataset.dialog);

        window["empty" + this.dataset.item] (dialog);
        dialog.showModal();
        dialog.querySelector ("input[name=email]").focus();
    }
}

async function saveUser (event) {
    event.preventDefault();

    const dialog = event.target.closest ("dialog");

    if (event.submitter.classList.contains ("save")) {
        const userId = event.target.querySelector ("input[name=userid]").value;
        const email = event.target.querySelector ("input[name=email]").value;
        const fullname = event.target.querySelector ("input[name=fullname]").value;
        const isActive = event.target.querySelector ("input[name=active]").checked;
        const roles = Array.from (event.target.querySelectorAll ("input[name=role]:checked")).map (checkbox => { return checkbox.value });
        let valid = true;

        if (email) {
            dialog.querySelector (".error[for=email]").hidden = true;
        } else {
            dialog.querySelector (".error[for=email]").hidden = false;
            valid = false;
        }
        if (fullname) {
            dialog.querySelector (".error[for=fullname]").hidden = true;
        } else {
            dialog.querySelector (".error[for=fullname]").hidden = false;
            valid = false;
        }

        if (valid) {
            event.target.querySelector ("button.save").disabled = true;

            try {
                const url = dialog.dataset.saveUrl + "/" + userId;
                const response = await fetch (url,
                                              {
                                                  method: "POST",
                                                  headers: { "Content-Type": "application/json" },
                                                  body: JSON.stringify ({email: email, fullname: fullname, isActive: isActive, roles: roles})
                                              });
                if (response.ok) {
                    dialog.close();
                    event.target.querySelector ("button.save").disabled = false;
                    loadData (document.querySelector (".users.loading"));

                    return true;
                } else {
                    console.error (url + " returned " + response.status);
                    dialog.querySelector (".error#failure").hidden = false;
                    dialog.querySelector ("button.save").disabled = false;

                    if ((response.status == 401) || (response.status == 403)) {
                        document.location.href = document.body.dataset.baseurl;
                    }

                    return true;
                }
            } catch (error) {
                console.error (error);
                dialog.querySelector (".error#failure").hidden = false;
                dialog.querySelector ("button.save").disabled = false;
            }
        } else {
            return false;
        }
    } else {
        dialog.close();
    }
}

async function inviteUser (event) {
    event.preventDefault();

    const dialog = event.target.closest ("dialog");

    if (event.submitter.classList.contains ("invite")) {
        const email = event.target.querySelector ("input[name=email]").value;
        const fullname = event.target.querySelector ("input[name=fullname").value;
        const roles = Array.from (event.target.querySelectorAll ("input[name=role]:checked")).map (checkbox => { return checkbox.value });
        let valid = true;

        if (email) {
            dialog.querySelector (".error[for=email]").hidden = true;
        } else {
            dialog.querySelector (".error[for=email]").hidden = false;
            valid = false;
        }
        if (fullname) {
            dialog.querySelector (".error[for=fullname]").hidden = true;
        } else {
            dialog.querySelector (".error[for=fullname]").hidden = false;
            valid = false;
        }

        if (valid) {
            event.target.querySelector ("button.invite").disabled = true;

            try {
                const url = dialog.dataset.inviteUrl;
                const response = await fetch (url,
                                              {
                                                  method: "PUT",
                                                  headers: { "Content-Type": "application/json" },
                                                  body: JSON.stringify ({email: email, fullname: fullname, roles: roles})
                                              });
                if (response.ok) {
                    dialog.close();
                    event.target.querySelector ("button.invite").disabled = false;
                    loadData (document.querySelector (".users.loading"));

                    return true;
                } else {
                    console.error (url + " returned " + response.status);
                    dialog.querySelector (".error#failure").hidden = false;
                    dialog.querySelector ("button.invite").disabled = false;

                    if ((response.status == 401) || (response.status == 403)) {
                        document.location.href = document.body.dataset.baseurl;
                    }

                    return true;
                }
            } catch (error) {
                console.error (error);
                dialog.querySelector (".error#failure").hidden = false;
                dialog.querySelector ("button.invite").disabled = false;
            }
        } else {
            return false;
        }
    } else {
        dialog.close();
    }
}

function populatePassword (container, token) {
    container.querySelector (".email").innerText = token.email;
    container.querySelector ("button.save").disabled = false;
    container.querySelector (".invalidPassword").hidden = true;
}

async function savePassword (event) {
    event.preventDefault();

    if (event.submitter.classList.contains ("save")) {
        const password = event.target.querySelector ("input[name=password]").value;
        const saveUrl = event.target.dataset.saveUrl;
        const loginUrl = event.target.dataset.loginUrl;

        if (password && (password.length >= 12)) {
            try {
                event.target.querySelector ("button.save").disabled = true;
                event.target.querySelector (".invalidPassword").hidden = true;
                const response = await fetch (saveUrl,
                                              {
                                                  method: "POST",
                                                  headers: { "Content-Type": "application/json" },
                                                  body: JSON.stringify ({password: password})
                                              });
                if (response.ok) {
                    document.location.href = loginUrl;

                    return true;
                } else {
                    console.error (saveUrl + " returned " + response.status);
                    event.target.querySelector (".error#failure").hidden = false;
                    event.target.querySelector ("button.save").disabled = false;

                    return false;
                }
            } catch (error) {
                console.error (saveUrl + " returned " + error);
                event.target.querySelector (".error#failure").hidden = false;
                event.target.querySelector ("button.save").disabled = false;
            }
        } else {
            event.target.querySelector (".invalidPassword").hidden = false;
            return false;
        }
    } else {
        dialog.close();
    }
}

async function login (event) {
    event.preventDefault();

    const email = event.target.querySelector ("input[name=email]").value;
    const password = event.target.querySelector ("input[name=password]").value;
    const loginUrl = event.target.dataset.loginUrl;

    if (email && password) {
        try {
            event.target.querySelector ("button#login").disabled = true;
            event.target.querySelector (".error#failure").hidden = true;
            event.target.querySelector (".invalidEmail").hidden = true;
            event.target.querySelector (".invalidPassword").hidden = true;

            const response = await fetch (loginUrl,
                                          {
                                              method: "POST",
                                              headers: { "Content-Type": "application/json" },
                                              body: JSON.stringify ({email: email, password: password})
                                          });
            if (response.ok) {
                event.target.querySelector ("button#login").disabled = false;

                document.location.href = document.body.dataset.baseurl;

                return true;
            } else {
                console.error (loginUrl + " returned " + response.status);
                event.target.querySelector (".error#failure").hidden = false;
                event.target.querySelector ("button#login").disabled = false;

                return false;
            }
        } catch (error) {
            console.error (loginUrl + " returned " + error);
            event.target.querySelector (".error#failure").hidden = false;
            event.target.querySelector ("button#login").disabled = false;
        }

        return true;
    } else {
        event.target.querySelector (".invalidEmail").hidden = email;
        event.target.querySelector (".invalidPassword").hidden = password;
        return false;
    }
}

function showForgotPassword (event) {
    event.preventDefault();

    document.querySelector ("form#login").hidden = true;
    document.querySelector ("form#forgot").hidden = false;
}

async function submitForgotPassword (event) {
    event.preventDefault();

    const email = event.target.querySelector ("input[name=email]").value;
    const resetUrl = event.target.dataset.resetUrl;

    if (email) {
        try {
            event.target.querySelector ("button#reset-password").disabled = true;
            const response = await fetch (resetUrl,
                                          {
                                              method: "POST",
                                              headers: { "Content-Type": "application/json" },
                                              body: JSON.stringify ({email: email})
                                          });
            if (response.ok) {
                document.querySelector ("form#forgot").hidden = true;
                document.querySelector ("div#reset-info").hidden = false;

                return true;
            } else {
                console.error (saveUrl + " returned " + response.status);
                event.target.querySelector (".error#failure").hidden = false;
                event.target.querySelector ("button#reset-password").disabled = false;

                return false;
            }
        } catch (error) {
            console.error (saveUrl + " returned " + error);
            event.target.querySelector (".error#failure").hidden = false;
            event.target.querySelector ("button#reset-password").disabled = false;
        }
    } else {
        event.target.querySelector (".invalidEmail").hidden = false;
        return false;
    }
}

function setupGlobalEnvironment() {
    document.querySelectorAll (".loading")
        .forEach (function (block) {
                      loadData (block);
                      block.addEventListener ("click", window["select" + block.dataset.item]);
                  });
    document.querySelectorAll ("form#login")
        .forEach (function (form) {
                      form.addEventListener ("submit", login);
                  });
    document.querySelectorAll ("button#forgot-password")
        .forEach (function (button) {
                      button.addEventListener ("click", showForgotPassword);
                  });
    document.querySelectorAll ("form#forgot")
        .forEach (function (form) {
                      form.addEventListener ("submit", submitForgotPassword);
                  });
}

document.addEventListener ("DOMContentLoaded", setupGlobalEnvironment);