'use client'

import {FormEvent, useState} from 'react'
import {ArrowUpRight, Check, Copy, FileCode2, Loader2, Send, Terminal, X} from 'lucide-react'
import {languageLabel, rawSnippetUrl, SnippetEditor, snippetUrl} from '@/components/snippet-editor'

const API_BASE = 'http://127.0.0.1:6868'

async function copyToClipboard(text: string) {
    if (navigator.clipboard && window.isSecureContext) {
        try {
            await navigator.clipboard.writeText(text);
            return true;
        } catch (err) {
        }
    }

    try {
        const textArea = document.createElement('textarea');
        textArea.value = text;

        textArea.style.position = 'fixed';
        textArea.style.left = '-999999px';
        textArea.style.top = '-999999px';
        document.body.appendChild(textArea);

        textArea.focus();
        textArea.select();

        const successful = document.execCommand('copy');
        document.body.removeChild(textArea);

        if (!successful) throw new Error('execCommand copy failed');
        return true;
    } catch (err) {
        return false;
    }
}

export default function Page() {
    const [content, setContent] = useState('')
    const [filename, setFilename] = useState('untitled.txt')
    const [snippetId, setSnippetId] = useState('')
    const [status, setStatus] = useState<'idle' | 'loading' | 'error'>('idle')
    const [error, setError] = useState('')
    const [copied, setCopied] = useState(false)

    async function submit(event: FormEvent) {
        event.preventDefault()
        if (!content.trim()) {
            setError('Add some content before publishing.');
            setStatus('error');
            return
        }
        setStatus('loading');
        setError('');
        setSnippetId('')
        try {
            const response = await fetch(`${API_BASE}/api/v1/snippets`, {
                method: 'POST',
                headers: {'Content-Type': 'application/json'},
                body: JSON.stringify({content, filename})
            })
            if (!response.ok) throw new Error(`Request failed with ${response.status}`)
            const data = await response.json()
            if (!data.snippet_id) throw new Error('The server did not return a snippet_id.')
            setSnippetId(data.snippet_id);
            setStatus('idle')
        } catch (caught) {
            setStatus('error');
            setError(caught instanceof Error ? caught.message : 'Could not reach the snippet server.')
        }
    }

    async function copyLink() {
        if (!snippetId) return
        await copyToClipboard(snippetUrl(snippetId));
        setCopied(true);
        window.setTimeout(() => setCopied(false), 1600)
    }

    function reset() {
        setContent('');
        setFilename('untitled.txt');
        setSnippetId('');
        setError('');
        setStatus('idle')
    }

    return (
        <main className="min-h-screen bg-background text-foreground">
            <header className="border-b border-border">
                <div className="mx-auto flex max-w-6xl items-center justify-between px-5 py-4 lg:px-8">
                    <a href="/" className="flex items-center gap-3 font-mono text-sm font-semibold tracking-tight"><span
                        className="grid size-8 place-items-center rounded-lg bg-primary text-primary-foreground"><Terminal
                        size={16}/></span>KSnippets</a>
                </div>
            </header>

            <div className="mx-auto max-w-6xl px-5 py-10 lg:px-8 lg:py-16">
                <form onSubmit={submit}>
                    <div className="mb-3 flex flex-wrap items-center justify-between gap-3">
                        <div className="flex items-center gap-2 text-sm font-medium"><FileCode2 size={16}
                                                                                                className="text-brand"/> New
                            snippet
                        </div>
                        <div className="flex items-center gap-2"><span
                            className="rounded-md bg-muted px-2.5 py-1 font-mono text-[11px] text-muted-foreground">{languageLabel(filename)}</span>
                            <button type="button" onClick={reset}
                                    className="rounded-md p-1.5 text-muted-foreground hover:bg-muted hover:text-foreground"
                                    aria-label="Clear editor"><X size={15}/></button>
                        </div>
                    </div>
                    <SnippetEditor value={content} filename={filename} onChange={setContent}/>
                    <div className="mt-4 flex flex-col gap-3 sm:flex-row sm:items-center sm:justify-between"><label
                        className="flex items-center gap-3 text-sm text-muted-foreground"><span
                        className="font-mono text-xs">filename</span><input value={filename}
                                                                            onChange={(event) => setFilename(event.target.value || 'untitled.txt')}
                                                                            className="w-44 border-b border-border bg-transparent py-1 text-foreground outline-none focus:border-brand"/></label>
                        <button disabled={status === 'loading'}
                                className="inline-flex items-center justify-center gap-2 rounded-lg bg-primary px-5 py-2.5 text-sm font-medium text-primary-foreground transition hover:bg-primary/90 disabled:cursor-wait disabled:opacity-70">{status === 'loading' ?
                            <Loader2 size={16} className="animate-spin"/> : <Send size={16}/>} Publish snippet
                        </button>
                    </div>
                </form>

                {status === 'error' && <div role="alert"
                                            className="mt-5 rounded-lg border border-destructive/30 bg-destructive/10 px-4 py-3 text-sm text-destructive">{error}</div>}
                {snippetId && <section className="mt-8 rounded-xl border border-brand/30 bg-brand/5 p-5">
                    <div className="flex flex-col gap-4 sm:flex-row sm:items-center sm:justify-between">
                        <div><p className="mb-1 text-xs font-medium uppercase tracking-widest text-brand">published
                            successfully</p><a href={`/${snippetId}`}
                                               className="font-mono text-sm text-foreground underline decoration-brand underline-offset-4">/{snippetId}</a>
                        </div>
                        <div className="flex flex-wrap gap-2">
                            <button type="button" onClick={copyLink}
                                    className="inline-flex items-center gap-2 rounded-lg border border-border bg-background px-3 py-2 text-xs font-medium hover:bg-muted">{copied ?
                                <Check size={14}/> : <Copy size={14}/>}{copied ? 'Copied' : 'Copy link'}</button>
                            <a href={rawSnippetUrl(snippetId)} target="_blank" rel="noreferrer"
                               className="inline-flex items-center gap-2 rounded-lg bg-primary px-3 py-2 text-xs font-medium text-primary-foreground">Raw <ArrowUpRight
                                size={14}/></a></div>
                    </div>
                </section>}
            </div>
        </main>
    )
}