import React from "react";
import {useSidebar} from "@/components/ui/sidebar";
import {Separator} from "@/components/ui/separator.tsx";
import {Button} from "@/components/ui/button.tsx";
import {Alert, AlertDescription, AlertTitle} from "@/components/ui/alert.tsx";
import {Checkbox} from "@/components/ui/checkbox.tsx";
import {Input} from "@/components/ui/input.tsx";
import {Label} from "@/components/ui/label.tsx";
import {Tabs, TabsContent, TabsList, TabsTrigger} from "@/components/ui/tabs.tsx";
import {
    Table,
    TableBody,
    TableCell,
    TableHead,
    TableHeader,
    TableRow,
} from "@/components/ui/table.tsx";
import {Shield, Trash2, Users} from "lucide-react";
import axios from "axios";

const apiBase = import.meta.env.DEV ? "http://localhost:8081/users" : "/users";
const API = axios.create({ baseURL: apiBase });

function getCookie(name: string) {
    return document.cookie.split('; ').reduce((r, v) => {
        const parts = v.split('=');
        return parts[0] === name ? decodeURIComponent(parts[1]) : r;
    }, "");
}

interface AdminSettingsProps {
    isTopbarOpen?: boolean;
}

export function AdminSettings({ isTopbarOpen = true }: AdminSettingsProps): React.ReactElement {
    const { state: sidebarState } = useSidebar();

    // Registration toggle
    const [allowRegistration, setAllowRegistration] = React.useState(true);
    const [regLoading, setRegLoading] = React.useState(false);

    // OIDC config
    const [oidcConfig, setOidcConfig] = React.useState({
        client_id: '',
        client_secret: '',
        issuer_url: '',
        authorization_url: '',
        token_url: '',
        identifier_path: 'sub',
        name_path: 'name',
        scopes: 'openid email profile'
    });
    const [oidcLoading, setOidcLoading] = React.useState(false);
    const [oidcError, setOidcError] = React.useState<string | null>(null);
    const [oidcSuccess, setOidcSuccess] = React.useState<string | null>(null);

    // Users/admins
    const [users, setUsers] = React.useState<Array<{ id: string; username: string; is_admin: boolean; is_oidc: boolean }>>([]);
    const [usersLoading, setUsersLoading] = React.useState(false);
    const [newAdminUsername, setNewAdminUsername] = React.useState("");
    const [makeAdminLoading, setMakeAdminLoading] = React.useState(false);
    const [makeAdminError, setMakeAdminError] = React.useState<string | null>(null);
    const [makeAdminSuccess, setMakeAdminSuccess] = React.useState<string | null>(null);

    React.useEffect(() => {
        const jwt = getCookie("jwt");
        if (!jwt) return;
        // Preload OIDC config and users
        API.get("/oidc-config", { headers: { Authorization: `Bearer ${jwt}` } })
            .then(res => { if (res.data) setOidcConfig(res.data); })
            .catch(() => {});
        fetchUsers();
        // eslint-disable-next-line react-hooks/exhaustive-deps
    }, []);

    // Load initial registration toggle status
    React.useEffect(() => {
        API.get("/registration-allowed")
            .then(res => {
                if (typeof res?.data?.allowed === 'boolean') {
                    setAllowRegistration(res.data.allowed);
                }
            })
            .catch(() => {});
    }, []);

    const fetchUsers = async () => {
        const jwt = getCookie("jwt");
        if (!jwt) return;
        setUsersLoading(true);
        try {
            const response = await API.get("/list", { headers: { Authorization: `Bearer ${jwt}` } });
            setUsers(response.data.users);
        } finally {
            setUsersLoading(false);
        }
    };

    const handleToggleRegistration = async (checked: boolean) => {
        setRegLoading(true);
        const jwt = getCookie("jwt");
        try {
            await API.patch("/registration-allowed", { allowed: checked }, { headers: { Authorization: `Bearer ${jwt}` } });
            setAllowRegistration(checked);
        } finally {
            setRegLoading(false);
        }
    };

    const handleOIDCConfigSubmit = async (e: React.FormEvent) => {
        e.preventDefault();
        setOidcLoading(true);
        setOidcError(null);
        setOidcSuccess(null);

        const required = ['client_id','client_secret','issuer_url','authorization_url','token_url'];
        const missing = required.filter(f => !oidcConfig[f as keyof typeof oidcConfig]);
        if (missing.length > 0) {
            setOidcError(`Missing required fields: ${missing.join(', ')}`);
            setOidcLoading(false);
            return;
        }

        const jwt = getCookie("jwt");
        try {
            await API.post("/oidc-config", oidcConfig, { headers: { Authorization: `Bearer ${jwt}` } });
            setOidcSuccess("OIDC configuration updated successfully!");
        } catch (err: any) {
            setOidcError(err?.response?.data?.error || "Failed to update OIDC configuration");
        } finally {
            setOidcLoading(false);
        }
    };

    const handleOIDCConfigChange = (field: string, value: string) => {
        setOidcConfig(prev => ({ ...prev, [field]: value }));
    };

    const makeUserAdmin = async (e: React.FormEvent) => {
        e.preventDefault();
        if (!newAdminUsername.trim()) return;
        setMakeAdminLoading(true);
        setMakeAdminError(null);
        setMakeAdminSuccess(null);
        const jwt = getCookie("jwt");
        try {
            await API.post("/make-admin", { username: newAdminUsername.trim() }, { headers: { Authorization: `Bearer ${jwt}` } });
            setMakeAdminSuccess(`User ${newAdminUsername} is now an admin`);
            setNewAdminUsername("");
            fetchUsers();
        } catch (err: any) {
            setMakeAdminError(err?.response?.data?.error || "Failed to make user admin");
        } finally {
            setMakeAdminLoading(false);
        }
    };

    const removeAdminStatus = async (username: string) => {
        if (!confirm(`Remove admin status from ${username}?`)) return;
        const jwt = getCookie("jwt");
        try {
            await API.post("/remove-admin", { username }, { headers: { Authorization: `Bearer ${jwt}` } });
            fetchUsers();
        } catch {}
    };

    const deleteUser = async (username: string) => {
        if (!confirm(`Delete user ${username}? This cannot be undone.`)) return;
        const jwt = getCookie("jwt");
        try {
            await API.delete("/delete-user", { headers: { Authorization: `Bearer ${jwt}` }, data: { username } });
            fetchUsers();
        } catch {}
    };

    const topMarginPx = isTopbarOpen ? 74 : 26;
    const leftMarginPx = sidebarState === 'collapsed' ? 26 : 8;
    const bottomMarginPx = 8;
    const wrapperStyle: React.CSSProperties = {
        marginLeft: leftMarginPx,
        marginRight: 17,
        marginTop: topMarginPx,
        marginBottom: bottomMarginPx,
        height: `calc(100vh - ${topMarginPx + bottomMarginPx}px)`
    };

    return (
        <div style={wrapperStyle} className="bg-[#18181b] text-white rounded-lg border-2 border-[#303032] overflow-hidden">
            <div className="h-full w-full flex flex-col">
                <div className="flex items-center justify-between px-3 pt-2 pb-2">
                    <h1 className="font-bold text-lg">Admin Settings</h1>
                </div>
                <Separator className="p-0.25 w-full"/>

                <div className="px-6 py-4 overflow-auto">
                    <Tabs defaultValue="registration" className="w-full">
                        <TabsList className="grid w-full grid-cols-4 mb-6">
                            <TabsTrigger value="registration" className="flex items-center gap-2">
                                <Users className="h-4 w-4"/>
                                General
                            </TabsTrigger>
                            <TabsTrigger value="oidc" className="flex items-center gap-2">
                                <Shield className="h-4 w-4"/>
                                OIDC
                            </TabsTrigger>
                            <TabsTrigger value="users" className="flex items-center gap-2">
                                <Users className="h-4 w-4"/>
                                Users
                            </TabsTrigger>
                            <TabsTrigger value="admins" className="flex items-center gap-2">
                                <Shield className="h-4 w-4"/>
                                Admins
                            </TabsTrigger>
                        </TabsList>

                        <TabsContent value="registration" className="space-y-6">
                            <div className="space-y-4">
                                <h3 className="text-lg font-semibold">User Registration</h3>
                                <label className="flex items-center gap-2">
                                    <Checkbox checked={allowRegistration} onCheckedChange={handleToggleRegistration} disabled={regLoading}/>
                                    Allow new account registration
                                </label>
                            </div>
                        </TabsContent>

                        <TabsContent value="oidc" className="space-y-6">
                            <div className="space-y-4">
                                <h3 className="text-lg font-semibold">External Authentication (OIDC)</h3>
                                <p className="text-sm text-muted-foreground">Configure external identity provider for OIDC/OAuth2 authentication.</p>

                                {oidcError && (
                                    <Alert variant="destructive">
                                        <AlertTitle>Error</AlertTitle>
                                        <AlertDescription>{oidcError}</AlertDescription>
                                    </Alert>
                                )}

                                <form onSubmit={handleOIDCConfigSubmit} className="space-y-4">
                                    <div className="space-y-2">
                                        <Label htmlFor="client_id">Client ID</Label>
                                        <Input id="client_id" value={oidcConfig.client_id} onChange={(e) => handleOIDCConfigChange('client_id', e.target.value)} placeholder="your-client-id" required />
                                    </div>
                                    <div className="space-y-2">
                                        <Label htmlFor="client_secret">Client Secret</Label>
                                        <Input id="client_secret" type="password" value={oidcConfig.client_secret} onChange={(e) => handleOIDCConfigChange('client_secret', e.target.value)} placeholder="your-client-secret" required />
                                    </div>
                                    <div className="space-y-2">
                                        <Label htmlFor="authorization_url">Authorization URL</Label>
                                        <Input id="authorization_url" value={oidcConfig.authorization_url} onChange={(e) => handleOIDCConfigChange('authorization_url', e.target.value)} placeholder="https://your-provider.com/application/o/authorize/" required />
                                    </div>
                                    <div className="space-y-2">
                                        <Label htmlFor="issuer_url">Issuer URL</Label>
                                        <Input id="issuer_url" value={oidcConfig.issuer_url} onChange={(e) => handleOIDCConfigChange('issuer_url', e.target.value)} placeholder="https://your-provider.com/application/o/termix/" required />
                                    </div>
                                    <div className="space-y-2">
                                        <Label htmlFor="token_url">Token URL</Label>
                                        <Input id="token_url" value={oidcConfig.token_url} onChange={(e) => handleOIDCConfigChange('token_url', e.target.value)} placeholder="https://your-provider.com/application/o/token/" required />
                                    </div>
                                    <div className="space-y-2">
                                        <Label htmlFor="identifier_path">User Identifier Path</Label>
                                        <Input id="identifier_path" value={oidcConfig.identifier_path} onChange={(e) => handleOIDCConfigChange('identifier_path', e.target.value)} placeholder="sub" required />
                                    </div>
                                    <div className="space-y-2">
                                        <Label htmlFor="name_path">Display Name Path</Label>
                                        <Input id="name_path" value={oidcConfig.name_path} onChange={(e) => handleOIDCConfigChange('name_path', e.target.value)} placeholder="name" required />
                                    </div>
                                    <div className="space-y-2">
                                        <Label htmlFor="scopes">Scopes</Label>
                                        <Input id="scopes" value={oidcConfig.scopes} onChange={(e) => handleOIDCConfigChange('scopes', (e.target as HTMLInputElement).value)} placeholder="openid email profile" required />
                                    </div>
                                    <div className="flex gap-2 pt-2">
                                        <Button type="submit" className="flex-1" disabled={oidcLoading}>{oidcLoading ? "Saving..." : "Save Configuration"}</Button>
                                        <Button type="button" variant="outline" onClick={() => setOidcConfig({ client_id: '', client_secret: '', issuer_url: '', authorization_url: '', token_url: '', identifier_path: 'sub', name_path: 'name', scopes: 'openid email profile' })}>Reset</Button>
                                    </div>

                                    {oidcSuccess && (
                                        <Alert>
                                            <AlertTitle>Success</AlertTitle>
                                            <AlertDescription>{oidcSuccess}</AlertDescription>
                                        </Alert>
                                    )}
                                </form>
                            </div>
                        </TabsContent>

                        <TabsContent value="users" className="space-y-6">
                            <div className="space-y-4">
                                <div className="flex items-center justify-between">
                                    <h3 className="text-lg font-semibold">User Management</h3>
                                    <Button onClick={fetchUsers} disabled={usersLoading} variant="outline" size="sm">{usersLoading ? "Loading..." : "Refresh"}</Button>
                                </div>
                                {usersLoading ? (
                                    <div className="text-center py-8 text-muted-foreground">Loading users...</div>
                                ) : (
                                    <div className="border rounded-md overflow-hidden">
                                        <Table>
                                            <TableHeader>
                                                <TableRow>
                                                    <TableHead className="px-4">Username</TableHead>
                                                    <TableHead className="px-4">Type</TableHead>
                                                    <TableHead className="px-4">Actions</TableHead>
                                                </TableRow>
                                            </TableHeader>
                                            <TableBody>
                                                {users.map((user) => (
                                                    <TableRow key={user.id}>
                                                        <TableCell className="px-4 font-medium">
                                                            {user.username}
                                                            {user.is_admin && (
                                                                <span className="ml-2 inline-flex items-center px-2 py-1 rounded-full text-xs font-medium bg-muted/50 text-muted-foreground border border-border">Admin</span>
                                                            )}
                                                        </TableCell>
                                                        <TableCell className="px-4">{user.is_oidc ? "External" : "Local"}</TableCell>
                                                        <TableCell className="px-4">
                                                            <Button variant="ghost" size="sm" onClick={() => deleteUser(user.username)} className="text-red-600 hover:text-red-700 hover:bg-red-50" disabled={user.is_admin}>
                                                                <Trash2 className="h-4 w-4"/>
                                                            </Button>
                                                        </TableCell>
                                                    </TableRow>
                                                ))}
                                            </TableBody>
                                        </Table>
                                    </div>
                                )}
                            </div>
                        </TabsContent>

                        <TabsContent value="admins" className="space-y-6">
                            <div className="space-y-6">
                                <h3 className="text-lg font-semibold">Admin Management</h3>
                                <div className="space-y-4 p-6 border rounded-md bg-muted/50">
                                    <h4 className="font-medium">Make User Admin</h4>
                                    <form onSubmit={makeUserAdmin} className="space-y-4">
                                        <div className="space-y-2">
                                            <Label htmlFor="new-admin-username">Username</Label>
                                            <div className="flex gap-2">
                                                <Input id="new-admin-username" value={newAdminUsername} onChange={(e) => setNewAdminUsername(e.target.value)} placeholder="Enter username to make admin" required />
                                                <Button type="submit" disabled={makeAdminLoading || !newAdminUsername.trim()}>{makeAdminLoading ? "Adding..." : "Make Admin"}</Button>
                                            </div>
                                        </div>
                                        {makeAdminError && (
                                            <Alert variant="destructive">
                                                <AlertTitle>Error</AlertTitle>
                                                <AlertDescription>{makeAdminError}</AlertDescription>
                                            </Alert>
                                        )}
                                        {makeAdminSuccess && (
                                            <Alert>
                                                <AlertTitle>Success</AlertTitle>
                                                <AlertDescription>{makeAdminSuccess}</AlertDescription>
                                            </Alert>
                                        )}
                                    </form>
                                </div>

                                <div className="space-y-4">
                                    <h4 className="font-medium">Current Admins</h4>
                                    <div className="border rounded-md overflow-hidden">
                                        <Table>
                                            <TableHeader>
                                                <TableRow>
                                                    <TableHead className="px-4">Username</TableHead>
                                                    <TableHead className="px-4">Type</TableHead>
                                                    <TableHead className="px-4">Actions</TableHead>
                                                </TableRow>
                                            </TableHeader>
                                            <TableBody>
                                                {users.filter(u => u.is_admin).map((admin) => (
                                                    <TableRow key={admin.id}>
                                                        <TableCell className="px-4 font-medium">
                                                            {admin.username}
                                                            <span className="ml-2 inline-flex items-center px-2 py-1 rounded-full text-xs font-medium bg-muted/50 text-muted-foreground border border-border">Admin</span>
                                                        </TableCell>
                                                        <TableCell className="px-4">{admin.is_oidc ? "External" : "Local"}</TableCell>
                                                        <TableCell className="px-4">
                                                            <Button variant="ghost" size="sm" onClick={() => removeAdminStatus(admin.username)} className="text-orange-600 hover:text-orange-700 hover:bg-orange-50">
                                                                <Shield className="h-4 w-4"/>
                                                                Remove Admin
                                                            </Button>
                                                        </TableCell>
                                                    </TableRow>
                                                ))}
                                            </TableBody>
                                        </Table>
                                    </div>
                                </div>
                            </div>
                        </TabsContent>
                    </Tabs>
                </div>
            </div>
        </div>
    );
}

export default AdminSettings;