import { useCallback, useEffect, useState } from "react";
import { useNavigate } from "react-router-dom";
import { Icon } from "./icon";
import type { ToolInstance } from "../types/tool-instance";
import type { ToolType } from "../types/tool-type";
import {
	checkInstanceHealth,
	createInstance,
	deleteInstance,
	listInstances,
	recreateInstanceTunnel,
	restartInstance,
	startInstance,
	stopInstance,
} from "../api/sessions";
import styles from "./features/session/InstanceList.module.css";

const API_BASE_URL =
	import.meta.env.VITE_API_BASE_URL ?? "http://localhost:8000";

interface InstanceListProps {
	projectId: string;
	repoId: string;
	toolTypes: ToolType[];
}

export const InstanceList = ({
	projectId,
	repoId,
	toolTypes,
}: InstanceListProps) => {
	const navigate = useNavigate();
	const [instances, setInstances] = useState<ToolInstance[]>([]);
	const [loading, setLoading] = useState(false);
	const [showCreate, setShowCreate] = useState(false);
	const [selectedToolType, setSelectedToolType] = useState("");
	const [displayName, setDisplayName] = useState("");
	const [error, setError] = useState<string | null>(null);

	// Stop confirmation
	const [stopConfirmId, setStopConfirmId] = useState<string | null>(null);

	// Health check state
	const [healthStatus, setHealthStatus] = useState<
		Record<string, { healthy: boolean; lastCheck: number }>
	>({});

	const loadInstances = useCallback(async () => {
		setLoading(true);
		try {
			const data = await listInstances(projectId, repoId);
			setInstances(data);
		} catch {
			setError("Failed to load instances");
		} finally {
			setLoading(false);
		}
	}, [projectId, repoId]);

	useEffect(() => {
		void loadInstances();
	}, [loadInstances]);

	// Health check polling
	useEffect(() => {
		const runningInstances = instances.filter(
			(i) => i.status === "running" && i.url?.startsWith("http"),
		);
		if (runningInstances.length === 0) return;

		const checkHealth = async () => {
			for (const instance of runningInstances) {
				try {
					const health = await checkInstanceHealth(
						projectId,
						repoId,
						instance.id,
					);
					setHealthStatus((prev) => ({
						...prev,
						[instance.id]: { healthy: health.healthy, lastCheck: Date.now() },
					}));
				} catch {
					setHealthStatus((prev) => ({
						...prev,
						[instance.id]: { healthy: false, lastCheck: Date.now() },
					}));
				}
			}
		};

		// Check immediately
		void checkHealth();

		// Then every 30 seconds
		const interval = setInterval(() => void checkHealth(), 30000);
		return () => clearInterval(interval);
	}, [instances, projectId, repoId]);

	const handleCreate = async () => {
		if (!selectedToolType) return;
		setError(null);
		try {
			await createInstance(
				projectId,
				repoId,
				selectedToolType,
				displayName || undefined,
			);
			setShowCreate(false);
			setSelectedToolType("");
			setDisplayName("");
			await loadInstances();
		} catch {
			setError("Failed to create instance");
		}
	};

	const handleStart = async (instanceId: string) => {
		try {
			await startInstance(projectId, repoId, instanceId);
			await loadInstances();
		} catch {
			setError("Failed to start instance");
		}
	};

	const handleStop = async (instanceId: string) => {
		try {
			await stopInstance(projectId, repoId, instanceId);
			setStopConfirmId(null);
			await loadInstances();
		} catch {
			setError("Failed to stop instance");
		}
	};

	const handleRestart = async (instanceId: string) => {
		try {
			await restartInstance(projectId, repoId, instanceId);
			await loadInstances();
		} catch {
			setError("Failed to restart instance");
		}
	};

	const handleDelete = async (instanceId: string) => {
		if (!confirm("Are you sure you want to delete this instance?")) return;
		try {
			await deleteInstance(projectId, repoId, instanceId);
			// Update state immediately instead of reloading
			setInstances((prev) => prev.filter((i) => i.id !== instanceId));
		} catch {
			setError("Failed to delete instance");
		}
	};

	const handleRecreateTunnel = async (instanceId: string) => {
		try {
			await recreateInstanceTunnel(projectId, repoId, instanceId);
			await loadInstances();
		} catch {
			setError("Failed to recreate tunnel");
		}
	};

	const getStatusColor = (status: string) => {
		switch (status) {
			case "running":
				return "var(--success)";
			case "error":
				return "var(--danger)";
			case "pending":
			case "building":
				return "var(--warning)";
			default:
				return "var(--muted)";
		}
	};

	const isTunnelUnhealthy = (instance: ToolInstance) => {
		if (instance.status !== "running") return false;
		if (!instance.url?.startsWith("http")) return false;
		const health = healthStatus[instance.id];
		if (!health) return false;
		return !health.healthy;
	};

	return (
		<div className={styles.instanceList}>
			<div className={styles.instanceListHeader}>
				<h3>Tool Instances</h3>
				<button
					className="secondary-button small"
					onClick={() => setShowCreate(true)}
					type="button"
				>
					<Icon name="add" size="sm" />
					Launch Tool
				</button>
			</div>

			{error && <div className="error-message">{error}</div>}

			{loading ? (
				<p className="muted">Loading instances...</p>
			) : instances.length === 0 ? (
				<p className="muted">No instances yet. Launch a tool to get started.</p>
			) : (
				<div className={styles.instanceGrid}>
					{instances.map((instance) => (
						<div key={instance.id} className={styles.instanceCard}>
							<div className={styles.instanceInfo}>
								<div className={styles.instanceName}>
									{instance.display_name ||
										instance.tool_type_name ||
										"Unnamed Instance"}
								</div>
								<div className={styles.instanceMeta}>
									<span
										className={styles.statusDot}
										style={{ backgroundColor: getStatusColor(instance.status) }}
									/>
									{instance.status}
									{isTunnelUnhealthy(instance) && (
										<span className={styles.errorBadge} title="Tunnel unreachable">
											<Icon name="warning" size="sm" />
											tunnel error
										</span>
									)}
								</div>
							</div>
							<div className={styles.instanceActions}>
								{instance.status === "running" &&
									instance.url &&
									instance.tool_type_interfaces.includes("web") && (
										<>
											<a
												href={
													instance.url.startsWith("http")
														? instance.url
														: `${API_BASE_URL}${instance.url}`
												}
												target="_blank"
												rel="noopener noreferrer"
												className="secondary-button small"
											>
												<Icon name="external" size="sm" />
												Open
											</a>
											{isTunnelUnhealthy(instance) && (
												<button
													className="secondary-button small warning"
													onClick={() => void handleRecreateTunnel(instance.id)}
													type="button"
													title="Recreate tunnel"
												>
													<Icon name="refresh" size="sm" />
													Fix Tunnel
												</button>
											)}
										</>
									)}
								{instance.status === "running" &&
									instance.tool_type_interfaces.includes("terminal") && (
										<button
											className="secondary-button small"
											onClick={() =>
												navigate(`/instances/${instance.id}/terminal`)
											}
											type="button"
										>
											<Icon name="terminal" size="sm" />
											Terminal
										</button>
									)}
								{instance.status !== "running" && (
									<button
										className="secondary-button small"
										onClick={() => void handleStart(instance.id)}
										type="button"
									>
										<Icon name="play" size="sm" />
										Start
									</button>
								)}
								{instance.status === "running" && (
									<>
										{stopConfirmId === instance.id ? (
											<div className={styles.inlineConfirm}>
												<span>Stop?</span>
												<button
													className="ghost-button small danger-text"
													onClick={() => void handleStop(instance.id)}
													type="button"
												>
													Yes
												</button>
												<button
													className="ghost-button small"
													onClick={() => setStopConfirmId(null)}
													type="button"
												>
													No
												</button>
											</div>
										) : (
											<button
												className="ghost-button small"
												onClick={() => setStopConfirmId(instance.id)}
												type="button"
											>
												<Icon name="stop" size="sm" />
											</button>
										)}
										<button
											className="ghost-button small"
											onClick={() => void handleRestart(instance.id)}
											type="button"
										>
											<Icon name="refresh" size="sm" />
										</button>
									</>
								)}
								<button
									className="ghost-button small danger-text"
									onClick={() => void handleDelete(instance.id)}
									type="button"
								>
									<Icon name="delete" size="sm" />
								</button>
							</div>
						</div>
					))}
				</div>
			)}

			{showCreate && (
				<div className="dialog-overlay" role="dialog" aria-modal="true">
					<div className="dialog">
						<h2>Launch Tool</h2>
						<div className="stack">
							<label className="form-field">
								Tool Type
								<select
									value={selectedToolType}
									onChange={(e) => setSelectedToolType(e.target.value)}
								>
									<option value="">Select a tool...</option>
									{toolTypes.map((tool) => (
										<option key={tool.id} value={tool.id}>
											{tool.display_name}
										</option>
									))}
								</select>
							</label>
							<label className="form-field">
								Display Name (optional)
								<input
									type="text"
									value={displayName}
									onChange={(e) => setDisplayName(e.target.value)}
									placeholder="My Development Environment"
								/>
							</label>
							<div className="dialog-actions">
								<button
									className="secondary-button"
									onClick={() => setShowCreate(false)}
									type="button"
								>
									Cancel
								</button>
								<button
									className="primary-button"
									onClick={() => void handleCreate()}
									disabled={!selectedToolType}
									type="button"
								>
									Launch
								</button>
							</div>
						</div>
					</div>
				</div>
			)}
		</div>
	);
};