import { History, Send, Settings, Square } from 'lucide-react'
import { useCallback, useEffect, useRef, useState } from 'react'

import { Button } from '@/components/ui/button'
import {
	InputGroup,
	InputGroupAddon,
	InputGroupButton,
	InputGroupTextarea,
} from '@/components/ui/input-group'
import { saveSession } from '@/lib/db'

import { useAgent } from '../../agent/useAgent'
import { ConfigPanel } from './components/ConfigPanel'
import { HistoryDetail } from './components/HistoryDetail'
import { HistoryList } from './components/HistoryList'
import { ActivityCard, EventCard } from './components/cards'
import { EmptyState, Logo, MotionOverlay, StatusDot } from './components/misc'

type View =
	| { name: 'chat' }
	| { name: 'config' }
	| { name: 'history' }
	| { name: 'history-detail'; sessionId: string }

export default function App() {
	const [view, setView] = useState<View>({ name: 'chat' })
	const [inputValue, setInputValue] = useState('')
	const historyRef = useRef<HTMLDivElement>(null)
	const textareaRef = useRef<HTMLTextAreaElement>(null)

	const { status, history, activity, currentTask, config, execute, stop, configure } = useAgent()

	// Persist session when task finishes
	const prevStatusRef = useRef(status)
	useEffect(() => {
		const prev = prevStatusRef.current
		prevStatusRef.current = status

		if (
			prev === 'running' &&
			(status === 'completed' || status === 'error') &&
			history.length > 0 &&
			currentTask
		) {
			saveSession({ task: currentTask, history, status }).catch((err) =>
				console.error('[SidePanel] Failed to save session:', err)
			)
		}
	}, [status, history, currentTask])

	// Auto-scroll to bottom on new events
	useEffect(() => {
		if (historyRef.current) {
			historyRef.current.scrollTop = historyRef.current.scrollHeight
		}
	}, [history, activity])

	const handleSubmit = useCallback(
		(e?: React.SyntheticEvent) => {
			e?.preventDefault()
			if (!inputValue.trim() || status === 'running') return

			const taskToExecute = inputValue.trim()
			setInputValue('')

			execute(taskToExecute).catch((error) => {
				console.error('[SidePanel] Failed to execute task:', error)
			})
		},
		[inputValue, status, execute]
	)

	const handleStop = useCallback(() => {
		console.log('[SidePanel] Stopping task...')
		stop()
	}, [stop])

	const handleKeyDown = (e: React.KeyboardEvent) => {
		if (e.key === 'Enter' && !e.shiftKey && !e.nativeEvent.isComposing) {
			e.preventDefault()
			handleSubmit()
		}
	}

	// --- View routing ---

	if (view.name === 'config') {
		return (
			<ConfigPanel
				config={config}
				onSave={async (newConfig) => {
					await configure(newConfig)
					setView({ name: 'chat' })
				}}
				onClose={() => setView({ name: 'chat' })}
			/>
		)
	}

	if (view.name === 'history') {
		return (
			<HistoryList
				onSelect={(id) => setView({ name: 'history-detail', sessionId: id })}
				onBack={() => setView({ name: 'chat' })}
			/>
		)
	}

	if (view.name === 'history-detail') {
		return <HistoryDetail sessionId={view.sessionId} onBack={() => setView({ name: 'history' })} />
	}

	// --- Chat view ---

	const isRunning = status === 'running'
	const showEmptyState = !currentTask && history.length === 0 && !isRunning

	return (
		<div className="relative flex flex-col h-screen bg-background">
			<MotionOverlay active={isRunning} />
			{/* Header */}
			<header className="flex items-center justify-between border-b px-3 py-2">
				<div className="flex items-center gap-2">
					<Logo className="size-5" />
					<span className="text-sm font-medium">Page Agent Ext</span>
				</div>
				<div className="flex items-center gap-1">
					<StatusDot status={status} />
					<Button
						variant="ghost"
						size="icon-sm"
						onClick={() => setView({ name: 'history' })}
						className="cursor-pointer"
					>
						<History className="size-3.5" />
					</Button>
					<Button
						variant="ghost"
						size="icon-sm"
						onClick={() => setView({ name: 'config' })}
						className="cursor-pointer"
					>
						<Settings className="size-3.5" />
					</Button>
				</div>
			</header>

			{/* Content */}
			<main className="flex-1 overflow-hidden flex flex-col">
				{/* Current task */}
				{currentTask && (
					<div className="border-b px-3 py-2 bg-muted/30">
						<div className="text-[10px] text-muted-foreground uppercase tracking-wide">Task</div>
						<div className="text-xs font-medium truncate" title={currentTask}>
							{currentTask}
						</div>
					</div>
				)}

				{/* History */}
				<div ref={historyRef} className="flex-1 overflow-y-auto p-3 space-y-2">
					{showEmptyState && <EmptyState />}

					{history.map((event, index) => (
						// eslint-disable-next-line react-x/no-array-index-key
						<EventCard key={index} event={event} />
					))}

					{/* Activity indicator at bottom */}
					{activity && <ActivityCard activity={activity} />}
				</div>
			</main>

			{/* Input */}
			<footer className="border-t p-3">
				<InputGroup className="relative rounded-lg">
					<InputGroupTextarea
						ref={textareaRef}
						placeholder="Describe your task... (Enter to send)"
						value={inputValue}
						onChange={(e) => setInputValue(e.target.value)}
						onKeyDown={handleKeyDown}
						disabled={isRunning}
						className="text-xs pr-12 min-h-10"
					/>
					<InputGroupAddon align="inline-end" className="absolute bottom-0 right-0">
						{isRunning ? (
							<InputGroupButton
								size="icon-sm"
								variant="destructive"
								onClick={handleStop}
								className="size-7"
							>
								<Square className="size-3" />
							</InputGroupButton>
						) : (
							<InputGroupButton
								size="icon-sm"
								variant="default"
								onClick={() => handleSubmit()}
								disabled={!inputValue.trim()}
								className="size-7 cursor-pointer"
							>
								<Send className="size-3" />
							</InputGroupButton>
						)}
					</InputGroupAddon>
				</InputGroup>
			</footer>
		</div>
	)
}