"use client";

import * as TabsPrimitive from "@radix-ui/react-tabs";
import {
	Activity,
	AlertCircle,
	AlertTriangle,
	ArrowRight,
	BarChart3,
	Bot,
	CheckCircle2,
	ChevronRight,
	Circle,
	Clock,
	Download,
	FileJson,
	FileText,
	GitBranch,
	Layers,
	Loader2,
	Play,
	RotateCcw,
} from "lucide-react";
import { useCallback, useEffect, useState } from "react";
import { authFetch } from "@/lib/auth";
import { buildProjectUrl, useSFWorkspaceState } from "@/lib/sf-workspace-store";
import { cn } from "@/lib/utils";
import type {
	ProjectTotals,
	VisualizerData,
	VisualizerSlice,
	VisualizerTask,
} from "@/lib/visualizer-types";
import {
	formatCost,
	formatDuration,
	formatTokenCount,
} from "@/lib/visualizer-types";

// ─── Design Tokens ────────────────────────────────────────────────────────────

// Tab definitions — single source of truth
const TABS = [
	{ value: "progress", label: "Progress", Icon: Layers },
	{ value: "deps", label: "Dependencies", Icon: GitBranch },
	{ value: "metrics", label: "Metrics", Icon: BarChart3 },
	{ value: "timeline", label: "Timeline", Icon: Clock },
	{ value: "agent", label: "Agent", Icon: Bot },
	{ value: "changes", label: "Changes", Icon: Activity },
	{ value: "export", label: "Export", Icon: Download },
] as const;

type TabValue = (typeof TABS)[number]["value"];

// ─── Shared Primitives ────────────────────────────────────────────────────────

function statusIcon(status: "complete" | "active" | "pending" | "done") {
	switch (status) {
		case "complete":
		case "done":
			return <CheckCircle2 className="h-4 w-4 shrink-0 text-success" />;
		case "active":
			return <Play className="h-4 w-4 shrink-0 text-info" />;
		case "pending":
			return <Circle className="h-4 w-4 shrink-0 text-muted-foreground/50" />;
	}
}

function taskStatusIcon(task: VisualizerTask) {
	if (task.done) return statusIcon("done");
	if (task.active) return statusIcon("active");
	return statusIcon("pending");
}

function RiskBadge({ risk }: { risk: string }) {
	const color =
		risk === "high"
			? "bg-destructive/15 text-destructive border-destructive/25 ring-destructive/10"
			: risk === "medium"
				? "bg-warning/15 text-warning border-warning/25 ring-warning/10"
				: "bg-success/15 text-success border-success/25 ring-success/10";
	return (
		<span
			className={cn(
				"inline-flex items-center rounded border px-2 py-0.5 text-[11px] font-semibold uppercase tracking-widest",
				color,
			)}
		>
			{risk}
		</span>
	);
}

function formatRelative(isoDate: string): string {
	const diff = Date.now() - new Date(isoDate).getTime();
	if (diff < 60_000) return "just now";
	const min = Math.floor(diff / 60_000);
	if (min < 60) return `${min}m ago`;
	const hr = Math.floor(min / 60);
	if (hr < 24) return `${hr}h ago`;
	return `${Math.floor(hr / 24)}d ago`;
}

function formatTime(ts: number): string {
	const d = new Date(ts);
	return `${String(d.getHours()).padStart(2, "0")}:${String(d.getMinutes()).padStart(2, "0")}`;
}

/** Prominent section label with left accent bar */
function SectionLabel({ children }: { children: React.ReactNode }) {
	return (
		<div className="flex items-center gap-2.5">
			<div className="h-3.5 w-0.5 rounded-full bg-foreground/25" />
			<h3 className="text-xs font-semibold uppercase tracking-widest text-muted-foreground">
				{children}
			</h3>
		</div>
	);
}

/** Large empty state with icon */
function EmptyState({
	message,
	icon: Icon = AlertCircle,
}: {
	message: string;
	icon?: React.ComponentType<{ className?: string }>;
}) {
	return (
		<div className="flex flex-col items-center justify-center gap-4 rounded-xl border border-dashed border-border py-16 text-center">
			<div className="rounded-full border border-border bg-muted/50 p-4">
				<Icon className="h-6 w-6 text-muted-foreground" />
			</div>
			<p className="text-sm font-medium text-muted-foreground">{message}</p>
		</div>
	);
}

/** Metric card — key number with label */
function StatCard({
	label,
	value,
	sub,
	accent,
}: {
	label: string;
	value: string;
	sub?: string;
	accent?: "sky" | "emerald" | "amber" | "default";
}) {
	const accentClasses = {
		sky: "from-info/8 border-info/20",
		emerald: "from-success/8 border-success/20",
		amber: "from-warning/8 border-warning/20",
		default: "from-transparent border-border",
	}[accent ?? "default"];

	return (
		<div
			className={cn(
				"relative overflow-hidden rounded-xl border bg-gradient-to-br to-transparent p-5",
				accentClasses,
			)}
		>
			<p className="text-xs font-semibold uppercase tracking-widest text-muted-foreground">
				{label}
			</p>
			<p className="mt-2 text-2xl font-bold tabular-nums leading-none tracking-tight">
				{value}
			</p>
			{sub && <p className="mt-1.5 text-xs text-muted-foreground">{sub}</p>}
		</div>
	);
}

/** Horizontal progress bar with label */
function ProgressBar({
	value,
	max,
	color = "sky",
	animated = false,
}: {
	value: number;
	max: number;
	color?: "sky" | "emerald" | "amber";
	animated?: boolean;
}) {
	const pct = max > 0 ? Math.max(1, (value / max) * 100) : 0;
	const barColor = {
		sky: "bg-info",
		emerald: "bg-success",
		amber: "bg-warning",
	}[color];
	return (
		<div className="h-2 w-full overflow-hidden rounded-full bg-muted">
			<div
				className={cn(
					"h-full rounded-full transition-all duration-700",
					barColor,
					animated && "animate-pulse",
				)}
				style={{ width: `${pct}%` }}
			/>
		</div>
	);
}

// ─── Progress Tab ─────────────────────────────────────────────────────────────

function ProgressTab({ data }: { data: VisualizerData }) {
	if (data.milestones.length === 0) {
		return <EmptyState message="No milestones defined yet." icon={Layers} />;
	}

	const allSlices = data.milestones.flatMap((m) => m.slices);
	const riskCounts = { low: 0, medium: 0, high: 0 };
	for (const sl of allSlices) {
		if (sl.risk === "high") riskCounts.high++;
		else if (sl.risk === "medium") riskCounts.medium++;
		else riskCounts.low++;
	}

	return (
		<div className="space-y-6">
			{/* Risk Heatmap */}
			{allSlices.length > 0 && (
				<div className="rounded-xl border border-border bg-card p-6">
					<SectionLabel>Risk Heatmap</SectionLabel>
					<div className="mt-5 space-y-3">
						{data.milestones
							.filter((m) => m.slices.length > 0)
							.map((ms) => (
								<div key={ms.id} className="flex items-center gap-4">
									<span className="w-16 shrink-0 font-mono text-xs font-medium text-muted-foreground">
										{ms.id}
									</span>
									<div className="flex flex-wrap gap-1.5">
										{ms.slices.map((sl) => (
											<div
												key={sl.id}
												title={`${sl.id}: ${sl.title} (${sl.risk})`}
												className={cn(
													"h-6 w-6 rounded cursor-default transition-transform hover:scale-125",
													sl.risk === "high"
														? "bg-destructive"
														: sl.risk === "medium"
															? "bg-warning"
															: "bg-success",
												)}
											/>
										))}
									</div>
								</div>
							))}
					</div>
					<div className="mt-5 flex items-center gap-5 text-xs text-muted-foreground">
						<span className="flex items-center gap-2">
							<span className="h-3 w-3 rounded-sm bg-success" />
							Low ({riskCounts.low})
						</span>
						<span className="flex items-center gap-2">
							<span className="h-3 w-3 rounded-sm bg-warning" />
							Medium ({riskCounts.medium})
						</span>
						<span className="flex items-center gap-2">
							<span className="h-3 w-3 rounded-sm bg-destructive" />
							High ({riskCounts.high})
						</span>
					</div>
				</div>
			)}

			{/* Milestone tree */}
			<div className="space-y-4">
				{data.milestones.map((ms) => (
					<div
						key={ms.id}
						className="overflow-hidden rounded-xl border border-border bg-card"
					>
						{/* Milestone header */}
						<div className="flex items-center justify-between border-b border-border bg-muted/50 px-5 py-4">
							<div className="flex items-center gap-3">
								{statusIcon(ms.status)}
								<span className="font-mono text-xs font-semibold text-muted-foreground">
									{ms.id}
								</span>
								<span className="text-sm font-semibold">{ms.title}</span>
							</div>
							<span
								className={cn(
									"rounded-md px-2.5 py-1 text-xs font-semibold uppercase tracking-wider",
									ms.status === "complete"
										? "bg-success/15 text-success"
										: ms.status === "active"
											? "bg-info/15 text-info"
											: "bg-muted text-muted-foreground",
								)}
							>
								{ms.status}
							</span>
						</div>

						{ms.status === "pending" && ms.dependsOn.length > 0 && (
							<div className="px-5 py-2.5 text-xs text-muted-foreground border-b border-border/50">
								Depends on {ms.dependsOn.join(", ")}
							</div>
						)}

						{/* Slices */}
						{ms.slices.length > 0 && (
							<div className="divide-y divide-border/50">
								{ms.slices.map((sl) => {
									const doneTasks = sl.tasks.filter((t) => t.done).length;
									const slStatus = sl.done
										? "done"
										: sl.active
											? "active"
											: "pending";
									return (
										<div key={sl.id} className="px-5 py-4">
											<div className="flex items-center gap-3">
												{statusIcon(slStatus)}
												<span className="font-mono text-xs font-medium text-muted-foreground">
													{sl.id}
												</span>
												<span className="min-w-0 flex-1 truncate text-sm font-medium">
													{sl.title}
												</span>
												<div className="flex shrink-0 items-center gap-2.5">
													{sl.depends.length > 0 && (
														<span className="text-xs text-muted-foreground">
															deps: {sl.depends.join(", ")}
														</span>
													)}
													{sl.tasks.length > 0 && (
														<span className="font-mono text-xs font-medium text-muted-foreground">
															{doneTasks}/{sl.tasks.length}
														</span>
													)}
													<RiskBadge risk={sl.risk} />
												</div>
											</div>

											{/* Tasks — only shown for active or partially-done slices */}
											{(sl.active || sl.tasks.some((t) => t.active)) &&
												sl.tasks.length > 0 && (
													<div className="ml-7 mt-3 space-y-1">
														{sl.tasks.map((task) => (
															<div
																key={task.id}
																className={cn(
																	"flex items-center gap-2.5 rounded-lg px-3 py-2 transition-colors",
																	task.active
																		? "bg-info/8 border border-info/20"
																		: "hover:bg-muted/50",
																)}
															>
																{taskStatusIcon(task)}
																<span className="font-mono text-xs font-medium text-muted-foreground">
																	{task.id}
																</span>
																<span
																	className={cn(
																		"text-sm",
																		task.done &&
																			"text-muted-foreground line-through",
																		task.active && "font-semibold text-info",
																		!task.done &&
																			!task.active &&
																			"text-muted-foreground",
																	)}
																>
																	{task.title}
																</span>
																{task.active && (
																	<span className="ml-auto rounded-md bg-info/15 px-2 py-0.5 text-[11px] font-bold uppercase tracking-wider text-info">
																		running
																	</span>
																)}
															</div>
														))}
													</div>
												)}
										</div>
									);
								})}
							</div>
						)}
					</div>
				))}
			</div>
		</div>
	);
}

// ─── Deps Tab ─────────────────────────────────────────────────────────────────

function DepsTab({ data }: { data: VisualizerData }) {
	const cp = data.criticalPath;
	const activeMs = data.milestones.find((m) => m.status === "active");
	const milestoneDeps = data.milestones.filter((m) => m.dependsOn.length > 0);

	return (
		<div className="space-y-6">
			{/* Milestone Dependencies */}
			<div className="rounded-xl border border-border bg-card p-6">
				<SectionLabel>Milestone Dependencies</SectionLabel>
				<div className="mt-5">
					{milestoneDeps.length === 0 ? (
						<p className="text-sm text-muted-foreground">
							No milestone dependencies configured.
						</p>
					) : (
						<div className="flex flex-col gap-3">
							{milestoneDeps.flatMap((ms) =>
								ms.dependsOn.map((dep) => (
									<div
										key={`${dep}-${ms.id}`}
										className="flex items-center gap-3"
									>
										<span className="rounded-lg border border-info/25 bg-info/10 px-3 py-1.5 font-mono text-sm font-semibold text-info">
											{dep}
										</span>
										<ArrowRight className="h-4 w-4 text-muted-foreground" />
										<span className="rounded-lg border border-border bg-muted/50 px-3 py-1.5 font-mono text-sm font-medium">
											{ms.id}
										</span>
										<span className="text-sm text-muted-foreground">
											{ms.title}
										</span>
									</div>
								)),
							)}
						</div>
					)}
				</div>
			</div>

			{/* Slice Dependencies */}
			<div className="rounded-xl border border-border bg-card p-6">
				<SectionLabel>Slice Dependencies — Active Milestone</SectionLabel>
				<div className="mt-5">
					{!activeMs ? (
						<p className="text-sm text-muted-foreground">
							No active milestone.
						</p>
					) : (
						(() => {
							const slDeps = activeMs.slices.filter(
								(s) => s.depends.length > 0,
							);
							if (slDeps.length === 0)
								return (
									<p className="text-sm text-muted-foreground">
										No slice dependencies in {activeMs.id}.
									</p>
								);
							return (
								<div className="flex flex-col gap-3">
									{slDeps.flatMap((sl) =>
										sl.depends.map((dep) => (
											<div
												key={`${dep}-${sl.id}`}
												className="flex items-center gap-3"
											>
												<span className="rounded-lg border border-info/25 bg-info/10 px-3 py-1.5 font-mono text-sm font-semibold text-info">
													{dep}
												</span>
												<ArrowRight className="h-4 w-4 text-muted-foreground" />
												<span className="rounded-lg border border-border bg-muted/50 px-3 py-1.5 font-mono text-sm font-medium">
													{sl.id}
												</span>
												<span className="text-sm text-muted-foreground">
													{sl.title}
												</span>
											</div>
										)),
									)}
								</div>
							);
						})()
					)}
				</div>
			</div>

			{/* Critical Path */}
			<div className="rounded-xl border border-border bg-card p-6">
				<SectionLabel>Critical Path</SectionLabel>
				<div className="mt-5">
					{cp.milestonePath.length === 0 ? (
						<p className="text-sm text-muted-foreground">
							No critical path data.
						</p>
					) : (
						<div className="space-y-7">
							{/* Milestone chain */}
							<div>
								<p className="mb-3 text-xs font-semibold uppercase tracking-widest text-muted-foreground">
									Milestone Chain
								</p>
								<div className="flex flex-wrap items-center gap-2">
									{cp.milestonePath.map((id, i) => (
										<span key={id} className="flex items-center gap-2">
											<span className="rounded-lg border border-destructive/30 bg-destructive/10 px-3 py-1.5 font-mono text-sm font-bold text-destructive">
												{id}
											</span>
											{i < cp.milestonePath.length - 1 && (
												<ChevronRight className="h-4 w-4 text-muted-foreground" />
											)}
										</span>
									))}
								</div>
							</div>

							{/* Milestone slack */}
							{Object.keys(cp.milestoneSlack).length > 0 && (
								<div>
									<p className="mb-3 text-xs font-semibold uppercase tracking-widest text-muted-foreground">
										Milestone Slack
									</p>
									<div className="flex flex-col gap-2">
										{data.milestones
											.filter((m) => !cp.milestonePath.includes(m.id))
											.map((m) => (
												<div
													key={m.id}
													className="flex items-center gap-4 rounded-lg bg-muted/50 px-4 py-2.5"
												>
													<span className="w-16 font-mono text-sm font-semibold">
														{m.id}
													</span>
													<span className="text-sm text-muted-foreground">
														{m.title}
													</span>
													<span className="ml-auto font-mono text-xs text-muted-foreground">
														slack: {cp.milestoneSlack[m.id] ?? 0}
													</span>
												</div>
											))}
									</div>
								</div>
							)}

							{/* Slice critical path */}
							{cp.slicePath.length > 0 && (
								<div>
									<p className="mb-3 text-xs font-semibold uppercase tracking-widest text-muted-foreground">
										Slice Critical Path
									</p>
									<div className="flex flex-wrap items-center gap-2">
										{cp.slicePath.map((id, i) => (
											<span key={id} className="flex items-center gap-2">
												<span className="rounded-lg border border-warning/30 bg-warning/10 px-3 py-1.5 font-mono text-sm font-semibold text-warning">
													{id}
												</span>
												{i < cp.slicePath.length - 1 && (
													<ChevronRight className="h-4 w-4 text-muted-foreground" />
												)}
											</span>
										))}
									</div>
									{/* Bottleneck warnings */}
									{activeMs && (
										<div className="mt-3 space-y-2">
											{cp.slicePath
												.map((sid) => activeMs.slices.find((s) => s.id === sid))
												.filter(
													(sl): sl is VisualizerSlice =>
														sl != null && !sl.done && !sl.active,
												)
												.map((sl) => (
													<div
														key={sl.id}
														className="flex items-center gap-2.5 rounded-lg border border-warning/20 bg-warning/8 px-4 py-2.5 text-sm text-warning"
													>
														<AlertTriangle className="h-4 w-4 shrink-0" />
														<span className="font-mono font-semibold">
															{sl.id}
														</span>
														<span>
															is on the critical path but not yet started
														</span>
													</div>
												))}
										</div>
									)}
								</div>
							)}

							{/* Slice slack */}
							{Object.keys(cp.sliceSlack).length > 0 && (
								<div>
									<p className="mb-3 text-xs font-semibold uppercase tracking-widest text-muted-foreground">
										Slice Slack
									</p>
									<div className="flex flex-wrap gap-2">
										{Object.entries(cp.sliceSlack).map(([id, slack]) => (
											<span
												key={id}
												className="rounded-lg border border-border bg-muted/50 px-3 py-1.5 font-mono text-xs text-muted-foreground"
											>
												{id}: {slack}
											</span>
										))}
									</div>
								</div>
							)}
						</div>
					)}
				</div>
			</div>
		</div>
	);
}

// ─── Metrics Tab ──────────────────────────────────────────────────────────────

function MetricsTab({ data }: { data: VisualizerData }) {
	if (!data.totals) {
		return <EmptyState message="No metrics data available." icon={BarChart3} />;
	}

	const totals = data.totals;

	return (
		<div className="space-y-6">
			{/* Summary stats */}
			<div className="grid grid-cols-2 gap-4 sm:grid-cols-4">
				<StatCard
					label="Execution Units"
					value={String(totals.units)}
					accent="default"
				/>
				<StatCard
					label="Total Cost"
					value={formatCost(totals.cost)}
					accent="emerald"
				/>
				<StatCard
					label="Duration"
					value={formatDuration(totals.duration)}
					accent="sky"
				/>
				<StatCard
					label="Total Tokens"
					value={formatTokenCount(totals.tokens.total)}
					sub={`${formatTokenCount(totals.tokens.input)} in · ${formatTokenCount(totals.tokens.output)} out`}
					accent="amber"
				/>
			</div>

			{/* By Phase */}
			{data.byPhase.length > 0 && (
				<div className="rounded-xl border border-border bg-card p-6">
					<SectionLabel>Cost by Phase</SectionLabel>
					<div className="mt-5 space-y-5">
						{data.byPhase.map((phase) => {
							const pct =
								totals.cost > 0 ? (phase.cost / totals.cost) * 100 : 0;
							return (
								<div key={phase.phase}>
									<div className="mb-2 flex items-center justify-between">
										<span className="text-sm font-semibold">{phase.phase}</span>
										<div className="flex items-center gap-4 text-xs text-muted-foreground">
											<span className="font-mono font-medium text-foreground">
												{formatCost(phase.cost)}
											</span>
											<span>{pct.toFixed(1)}%</span>
											<span>{formatTokenCount(phase.tokens.total)} tok</span>
											<span>{phase.units} units</span>
										</div>
									</div>
									<ProgressBar value={pct} max={100} color="sky" />
								</div>
							);
						})}
					</div>
				</div>
			)}

			{/* By Model */}
			{data.byModel.length > 0 && (
				<div className="rounded-xl border border-border bg-card p-6">
					<SectionLabel>Cost by Model</SectionLabel>
					<div className="mt-5 space-y-5">
						{data.byModel.map((model) => {
							const pct =
								totals.cost > 0 ? (model.cost / totals.cost) * 100 : 0;
							return (
								<div key={model.model}>
									<div className="mb-2 flex items-center justify-between">
										<span className="font-mono text-sm font-medium">
											{model.model}
										</span>
										<div className="flex items-center gap-4 text-xs text-muted-foreground">
											<span className="font-mono font-medium text-foreground">
												{formatCost(model.cost)}
											</span>
											<span>{pct.toFixed(1)}%</span>
											<span>{formatTokenCount(model.tokens.total)} tok</span>
											<span>{model.units} units</span>
										</div>
									</div>
									<ProgressBar value={pct} max={100} color="emerald" />
								</div>
							);
						})}
					</div>
				</div>
			)}

			{/* By Slice */}
			{data.bySlice.length > 0 && (
				<div className="rounded-xl border border-border bg-card p-6">
					<SectionLabel>Cost by Slice</SectionLabel>
					<div className="mt-5 overflow-x-auto">
						<table className="w-full text-sm">
							<thead>
								<tr className="border-b border-border text-left text-xs font-semibold uppercase tracking-widest text-muted-foreground">
									<th className="pb-3 pr-5">Slice</th>
									<th className="pb-3 pr-5 text-right">Units</th>
									<th className="pb-3 pr-5 text-right">Cost</th>
									<th className="pb-3 pr-5 text-right">Duration</th>
									<th className="pb-3 text-right">Tokens</th>
								</tr>
							</thead>
							<tbody className="divide-y divide-border/50">
								{data.bySlice.map((sl) => (
									<tr
										key={sl.sliceId}
										className="transition-colors hover:bg-muted/50"
									>
										<td className="py-3 pr-5 font-mono text-xs font-semibold">
											{sl.sliceId}
										</td>
										<td className="py-3 pr-5 text-right tabular-nums text-muted-foreground">
											{sl.units}
										</td>
										<td className="py-3 pr-5 text-right tabular-nums font-medium">
											{formatCost(sl.cost)}
										</td>
										<td className="py-3 pr-5 text-right tabular-nums text-muted-foreground">
											{formatDuration(sl.duration)}
										</td>
										<td className="py-3 text-right tabular-nums text-muted-foreground">
											{formatTokenCount(sl.tokens.total)}
										</td>
									</tr>
								))}
							</tbody>
						</table>
					</div>
				</div>
			)}

			{/* Projections */}
			{data.bySlice.length >= 2 && (
				<ProjectionsSection data={data} totals={totals} />
			)}
		</div>
	);
}

function ProjectionsSection({
	data,
	totals,
}: {
	data: VisualizerData;
	totals: ProjectTotals;
}) {
	const sliceLevelEntries = data.bySlice.filter((s) => s.sliceId.includes("/"));
	if (sliceLevelEntries.length < 2) return null;

	const totalSliceCost = sliceLevelEntries.reduce((sum, s) => sum + s.cost, 0);
	const avgCostPerSlice = totalSliceCost / sliceLevelEntries.length;
	const projectedRemaining = avgCostPerSlice * data.remainingSliceCount;
	const projectedTotal = totals.cost + projectedRemaining;
	const burnRate =
		totals.duration > 0 ? totals.cost / (totals.duration / 3_600_000) : 0;

	return (
		<div className="rounded-xl border border-border bg-card p-6">
			<SectionLabel>Projections</SectionLabel>
			<div className="mt-5 grid grid-cols-2 gap-4 sm:grid-cols-4">
				<StatCard label="Avg / Slice" value={formatCost(avgCostPerSlice)} />
				<StatCard
					label="Projected Remaining"
					value={formatCost(projectedRemaining)}
					sub={`${data.remainingSliceCount} slices left`}
				/>
				<StatCard label="Projected Total" value={formatCost(projectedTotal)} />
				{burnRate > 0 && (
					<StatCard label="Burn Rate" value={`${formatCost(burnRate)}/hr`} />
				)}
			</div>
			{projectedTotal > 2 * totals.cost && data.remainingSliceCount > 0 && (
				<div className="mt-4 flex items-center gap-2.5 rounded-lg border border-warning/20 bg-warning/8 px-4 py-3 text-sm text-warning">
					<AlertTriangle className="h-4 w-4 shrink-0" />
					Projected total {formatCost(projectedTotal)} exceeds 2× current spend
				</div>
			)}
		</div>
	);
}

// ─── Timeline Tab ─────────────────────────────────────────────────────────────

function TimelineTab({ data }: { data: VisualizerData }) {
	const sorted = [...data.units].sort((a, b) => a.startedAt - b.startedAt);
	const recent = sorted.slice(-30);
	const hasRunningUnit = recent.some(
		(u) => !u.finishedAt || u.finishedAt === 0,
	);
	const [runningNow, setRunningNow] = useState(() => Date.now());

	useEffect(() => {
		if (!hasRunningUnit) return;
		const interval = window.setInterval(() => {
			setRunningNow(Date.now());
		}, 1000);
		return () => window.clearInterval(interval);
	}, [hasRunningUnit]);

	const referenceNow = hasRunningUnit ? runningNow : 0;
	const durationForUnit = useCallback(
		(unit: VisualizerData["units"][number]) =>
			(unit.finishedAt || referenceNow) - unit.startedAt,
		[referenceNow],
	);

	if (data.units.length === 0) {
		return <EmptyState message="No execution history yet." icon={Clock} />;
	}

	const maxDuration = Math.max(...recent.map(durationForUnit), 1);

	return (
		<div className="space-y-4">
			<div className="overflow-hidden rounded-xl border border-border bg-card">
				{/* Header */}
				<div className="border-b border-border bg-muted/50 px-6 py-4">
					<SectionLabel>Execution Timeline</SectionLabel>
					<p className="mt-1.5 text-xs text-muted-foreground">
						Showing {recent.length} of {data.units.length} units — most recent
						first
					</p>
				</div>

				{/* Column headers */}
				<div className="grid grid-cols-[3.5rem_1.5rem_5rem_8rem_1fr_4.5rem_5rem] items-center gap-3 border-b border-border/50 px-6 py-2.5 text-xs font-semibold uppercase tracking-widest text-muted-foreground">
					<span>Time</span>
					<span />
					<span>Type</span>
					<span>ID</span>
					<span>Duration</span>
					<span className="text-right">Time</span>
					<span className="text-right">Cost</span>
				</div>

				<div className="divide-y divide-border/40">
					{[...recent].reverse().map((unit, i) => {
						const duration = durationForUnit(unit);
						const pct = (duration / maxDuration) * 100;
						const isRunning = !unit.finishedAt || unit.finishedAt === 0;
						return (
							<div
								key={`${unit.id}-${unit.startedAt}-${i}`}
								className="grid grid-cols-[3.5rem_1.5rem_5rem_8rem_1fr_4.5rem_5rem] items-center gap-3 px-6 py-3.5 transition-colors hover:bg-muted/50"
							>
								<span className="font-mono text-xs text-muted-foreground">
									{formatTime(unit.startedAt)}
								</span>
								{isRunning ? (
									<Play className="h-3.5 w-3.5 shrink-0 text-info" />
								) : (
									<CheckCircle2 className="h-3.5 w-3.5 shrink-0 text-success" />
								)}
								<span className="truncate text-xs font-medium">
									{unit.type}
								</span>
								<span className="truncate font-mono text-xs text-muted-foreground">
									{unit.id}
								</span>
								<div className="hidden sm:block">
									<ProgressBar
										value={pct}
										max={100}
										color="sky"
										animated={isRunning}
									/>
								</div>
								<span className="text-right font-mono text-xs tabular-nums text-muted-foreground">
									{formatDuration(duration)}
								</span>
								<span className="text-right font-mono text-xs tabular-nums font-medium">
									{formatCost(unit.cost)}
								</span>
							</div>
						);
					})}
				</div>
			</div>
		</div>
	);
}

// ─── Agent Tab ────────────────────────────────────────────────────────────────

function AgentTab({ data }: { data: VisualizerData }) {
	const activity = data.agentActivity;

	if (!activity) {
		return (
			<EmptyState message="No agent activity data available." icon={Bot} />
		);
	}

	const completed = activity.completedUnits;
	const total = Math.max(completed, activity.totalSlices);
	const pct =
		total > 0 ? Math.min(100, Math.round((completed / total) * 100)) : 0;

	return (
		<div className="space-y-6">
			{/* Status card */}
			<div className="rounded-xl border border-border bg-card p-6">
				<div className="flex items-center justify-between">
					<div className="flex items-center gap-4">
						<div
							className={cn(
								"relative flex h-10 w-10 items-center justify-center rounded-full",
								activity.active ? "bg-success/15" : "bg-muted",
							)}
						>
							{activity.active && (
								<div className="absolute inset-0 animate-ping rounded-full bg-success/20" />
							)}
							<div
								className={cn(
									"h-3 w-3 rounded-full",
									activity.active ? "bg-success" : "bg-muted-foreground/30",
								)}
							/>
						</div>
						<div>
							<p className="text-xl font-bold">
								{activity.active ? "Active" : "Idle"}
							</p>
							<p className="text-sm text-muted-foreground">
								{activity.active ? "Agent is running" : "Waiting for next task"}
							</p>
						</div>
					</div>
					{activity.active && (
						<div className="text-right">
							<p className="font-mono text-lg font-bold">
								{formatDuration(activity.elapsed)}
							</p>
							<p className="text-xs text-muted-foreground">elapsed</p>
						</div>
					)}
				</div>

				{activity.currentUnit && (
					<div className="mt-5 flex items-center gap-3 rounded-xl border border-info/20 bg-info/8 px-5 py-3.5">
						<Play className="h-4 w-4 shrink-0 text-info" />
						<div>
							<p className="text-xs text-muted-foreground">
								Currently executing
							</p>
							<p className="mt-0.5 font-mono text-sm font-semibold text-info">
								{activity.currentUnit.type} — {activity.currentUnit.id}
							</p>
						</div>
					</div>
				)}
			</div>

			{/* Completion progress */}
			{total > 0 && (
				<div className="rounded-xl border border-border bg-card p-6">
					<div className="mb-4 flex items-center justify-between">
						<SectionLabel>Completion Progress</SectionLabel>
						<span className="font-mono text-sm text-muted-foreground">
							{completed} / {total} slices
						</span>
					</div>
					<ProgressBar value={completed} max={total} color="emerald" />
					<div className="mt-3 flex items-center justify-between text-xs text-muted-foreground">
						<span>{pct}% complete</span>
						<span>{total - completed} remaining</span>
					</div>
				</div>
			)}

			{/* Stats grid */}
			<div className="grid grid-cols-2 gap-4 sm:grid-cols-4">
				<StatCard
					label="Completion Rate"
					value={
						activity.completionRate > 0
							? `${activity.completionRate.toFixed(1)}/hr`
							: "—"
					}
					accent="sky"
				/>
				<StatCard
					label="Session Cost"
					value={formatCost(activity.sessionCost)}
					accent="emerald"
				/>
				<StatCard
					label="Session Tokens"
					value={formatTokenCount(activity.sessionTokens)}
					accent="amber"
				/>
				<StatCard label="Completed" value={String(activity.completedUnits)} />
			</div>

			{/* Recent units */}
			{data.units.filter((u) => u.finishedAt > 0).length > 0 && (
				<div className="overflow-hidden rounded-xl border border-border bg-card">
					<div className="border-b border-border bg-muted/50 px-6 py-4">
						<SectionLabel>Recent Completed Units</SectionLabel>
					</div>
					<div className="divide-y divide-border/40">
						{data.units
							.filter((u) => u.finishedAt > 0)
							.slice(-5)
							.reverse()
							.map((u, i) => (
								<div
									key={`${u.id}-${i}`}
									className="flex items-center gap-4 px-6 py-4 transition-colors hover:bg-muted/50"
								>
									<span className="w-12 font-mono text-xs text-muted-foreground">
										{formatTime(u.startedAt)}
									</span>
									<CheckCircle2 className="h-4 w-4 shrink-0 text-success" />
									<span className="flex-1 truncate text-sm font-medium">
										{u.type}
									</span>
									<span className="font-mono text-xs text-muted-foreground">
										{u.id}
									</span>
									<span className="font-mono text-xs tabular-nums text-muted-foreground">
										{formatDuration(u.finishedAt - u.startedAt)}
									</span>
									<span className="font-mono text-xs tabular-nums font-semibold">
										{formatCost(u.cost)}
									</span>
								</div>
							))}
					</div>
				</div>
			)}
		</div>
	);
}

// ─── Changes Tab ──────────────────────────────────────────────────────────────

function ChangesTab({ data }: { data: VisualizerData }) {
	const entries = data.changelog.entries;

	if (entries.length === 0) {
		return <EmptyState message="No completed slices yet." icon={Activity} />;
	}

	const sorted = [...entries].reverse();

	return (
		<div className="space-y-4">
			{sorted.map((entry, i) => (
				<div
					key={`${entry.milestoneId}-${entry.sliceId}-${i}`}
					className="overflow-hidden rounded-xl border border-border bg-card"
				>
					{/* Header */}
					<div className="flex items-center justify-between border-b border-border bg-muted/50 px-6 py-4">
						<div className="flex items-center gap-3">
							<CheckCircle2 className="h-4 w-4 shrink-0 text-success" />
							<span className="font-mono text-xs font-bold text-success">
								{entry.milestoneId}/{entry.sliceId}
							</span>
							<span className="text-sm font-semibold">{entry.title}</span>
						</div>
						{entry.completedAt && (
							<span className="text-xs text-muted-foreground">
								{formatRelative(entry.completedAt)}
							</span>
						)}
					</div>

					<div className="px-6 py-5 space-y-5">
						{/* One-liner */}
						{entry.oneLiner && (
							<p className="text-sm text-muted-foreground italic leading-relaxed border-l-2 border-muted pl-4">
								&ldquo;{entry.oneLiner}&rdquo;
							</p>
						)}

						{/* Files modified */}
						{entry.filesModified.length > 0 && (
							<div>
								<p className="mb-3 text-xs font-semibold uppercase tracking-widest text-muted-foreground">
									Files Modified
								</p>
								<div className="space-y-2">
									{entry.filesModified.map((f, fi) => (
										<div
											key={fi}
											className="flex items-start gap-3 rounded-lg bg-muted/50 px-4 py-2.5"
										>
											<CheckCircle2 className="mt-0.5 h-3.5 w-3.5 shrink-0 text-success/70" />
											<span className="font-mono text-xs font-medium text-muted-foreground">
												{f.path}
											</span>
											{f.description && (
												<span className="ml-1 text-xs text-muted-foreground">
													— {f.description}
												</span>
											)}
										</div>
									))}
								</div>
							</div>
						)}
					</div>
				</div>
			))}
		</div>
	);
}

// ─── Export Tab ───────────────────────────────────────────────────────────────

function ExportTab({ data }: { data: VisualizerData }) {
	const downloadBlob = useCallback(
		(content: string, filename: string, mimeType: string) => {
			const blob = new Blob([content], { type: mimeType });
			const url = URL.createObjectURL(blob);
			const a = document.createElement("a");
			a.href = url;
			a.download = filename;
			document.body.appendChild(a);
			a.click();
			document.body.removeChild(a);
			URL.revokeObjectURL(url);
		},
		[],
	);

	const generateMarkdown = useCallback(() => {
		const lines: string[] = [];
		lines.push("# SF Workflow Report");
		lines.push("");
		lines.push(`Generated: ${new Date().toISOString()}`);
		lines.push(`Phase: ${data.phase}`);
		lines.push("");
		lines.push("## Milestones");
		lines.push("");
		for (const ms of data.milestones) {
			const icon =
				ms.status === "complete" ? "✓" : ms.status === "active" ? "▸" : "○";
			lines.push(`### ${icon} ${ms.id}: ${ms.title} (${ms.status})`);
			if (ms.dependsOn.length > 0)
				lines.push(`Depends on: ${ms.dependsOn.join(", ")}`);
			lines.push("");
			for (const sl of ms.slices) {
				const slIcon = sl.done ? "✓" : sl.active ? "▸" : "○";
				lines.push(`- ${slIcon} **${sl.id}**: ${sl.title} [risk: ${sl.risk}]`);
				for (const t of sl.tasks) {
					const tIcon = t.done ? "✓" : t.active ? "▸" : "○";
					lines.push(`  - ${tIcon} ${t.id}: ${t.title}`);
				}
			}
			lines.push("");
		}
		if (data.totals) {
			lines.push("## Metrics Summary");
			lines.push("");
			lines.push(`| Metric | Value |`);
			lines.push(`|--------|-------|`);
			lines.push(`| Units | ${data.totals.units} |`);
			lines.push(`| Total Cost | ${formatCost(data.totals.cost)} |`);
			lines.push(`| Duration | ${formatDuration(data.totals.duration)} |`);
			lines.push(`| Tokens | ${formatTokenCount(data.totals.tokens.total)} |`);
			lines.push("");
		}
		if (data.criticalPath.milestonePath.length > 0) {
			lines.push("## Critical Path");
			lines.push("");
			lines.push(`Milestone: ${data.criticalPath.milestonePath.join(" → ")}`);
			if (data.criticalPath.slicePath.length > 0) {
				lines.push(`Slice: ${data.criticalPath.slicePath.join(" → ")}`);
			}
			lines.push("");
		}
		if (data.changelog.entries.length > 0) {
			lines.push("## Changelog");
			lines.push("");
			for (const entry of data.changelog.entries) {
				lines.push(`### ${entry.milestoneId}/${entry.sliceId}: ${entry.title}`);
				if (entry.oneLiner) lines.push(`> ${entry.oneLiner}`);
				if (entry.filesModified.length > 0) {
					lines.push("Files:");
					for (const f of entry.filesModified)
						lines.push(`- \`${f.path}\` — ${f.description}`);
				}
				if (entry.completedAt) lines.push(`Completed: ${entry.completedAt}`);
				lines.push("");
			}
		}
		return lines.join("\n");
	}, [data]);

	const handleMarkdown = () =>
		downloadBlob(generateMarkdown(), "sf-report.md", "text/markdown");
	const handleJSON = () =>
		downloadBlob(
			JSON.stringify(data, null, 2),
			"sf-report.json",
			"application/json",
		);

	return (
		<div className="space-y-6">
			<div className="rounded-xl border border-border bg-card p-6">
				<SectionLabel>Export Project Data</SectionLabel>
				<p className="mt-3 text-sm leading-relaxed text-muted-foreground">
					Download the current visualizer data as a structured report. Markdown
					includes milestones, metrics, critical path, and changelog in a
					readable format. JSON contains the full raw data payload.
				</p>

				<div className="mt-7 grid gap-4 sm:grid-cols-2">
					<button
						type="button"
						onClick={handleMarkdown}
						className="group flex items-center gap-5 rounded-xl border border-border bg-muted/50 p-5 text-left transition-all hover:border-info/40 hover:bg-info/5"
					>
						<div className="rounded-xl border border-info/20 bg-info/10 p-4 transition-colors group-hover:bg-info/15">
							<FileText className="h-6 w-6 text-info" />
						</div>
						<div className="flex-1">
							<p className="text-sm font-semibold transition-colors group-hover:text-info">
								Download Markdown
							</p>
							<p className="mt-1 text-xs text-muted-foreground">
								Human-readable report with tables and structure
							</p>
						</div>
						<Download className="h-4 w-4 shrink-0 text-muted-foreground/0 transition-all group-hover:text-info/70" />
					</button>

					<button
						type="button"
						onClick={handleJSON}
						className="group flex items-center gap-5 rounded-xl border border-border bg-muted/50 p-5 text-left transition-all hover:border-success/40 hover:bg-success/5"
					>
						<div className="rounded-xl border border-success/20 bg-success/10 p-4 transition-colors group-hover:bg-success/15">
							<FileJson className="h-6 w-6 text-success" />
						</div>
						<div className="flex-1">
							<p className="text-sm font-semibold transition-colors group-hover:text-success">
								Download JSON
							</p>
							<p className="mt-1 text-xs text-muted-foreground">
								Full raw data payload for tooling
							</p>
						</div>
						<Download className="h-4 w-4 shrink-0 text-muted-foreground/0 transition-all group-hover:text-success/70" />
					</button>
				</div>
			</div>
		</div>
	);
}

// ─── Custom Tab Bar ────────────────────────────────────────────────────────────

function VisualizerTabs({
	defaultValue,
	children,
}: {
	defaultValue: TabValue;
	children: React.ReactNode;
}) {
	return (
		<TabsPrimitive.Root
			defaultValue={defaultValue}
			className="flex h-full flex-col overflow-hidden"
		>
			{children}
		</TabsPrimitive.Root>
	);
}

function VisualizerTabList() {
	return (
		<TabsPrimitive.List className="flex shrink-0 justify-center border-b border-border bg-background px-6">
			{TABS.map(({ value, label, Icon }) => (
				<TabsPrimitive.Trigger
					key={value}
					value={value}
					className={cn(
						// Base
						"group relative flex items-center gap-2 px-4 py-3.5 text-sm font-medium outline-none",
						"text-muted-foreground transition-colors duration-150",
						// Hover
						"hover:text-foreground",
						// Active (selected) — text
						"data-[state=active]:text-foreground",
						// Focus visible
						"focus-visible:text-foreground",
						// Disabled
						"disabled:pointer-events-none disabled:opacity-40",
					)}
				>
					{/* Active bottom border indicator */}
					<span
						className={cn(
							"pointer-events-none absolute bottom-0 left-0 right-0 h-0.5 rounded-t-full",
							"bg-foreground opacity-0 transition-opacity duration-150",
							"group-data-[state=active]:opacity-100",
						)}
					/>

					{/* Hover background */}
					<span className="absolute inset-x-0 inset-y-1.5 rounded-lg bg-muted/0 transition-colors duration-150 group-hover:bg-muted group-data-[state=active]:bg-transparent" />

					{/* Icon */}
					<Icon className="relative h-4 w-4 shrink-0 transition-colors duration-150 text-muted-foreground group-hover:text-muted-foreground group-data-[state=active]:text-foreground" />

					{/* Label */}
					<span className="relative">{label}</span>
				</TabsPrimitive.Trigger>
			))}
		</TabsPrimitive.List>
	);
}

// ─── Main Component ───────────────────────────────────────────────────────────

export function VisualizerView() {
	const workspace = useSFWorkspaceState();
	const projectCwd = workspace.boot?.project.cwd;
	const [data, setData] = useState<VisualizerData | null>(null);
	const [loading, setLoading] = useState(true);
	const [error, setError] = useState<string | null>(null);

	const fetchData = useCallback(async () => {
		try {
			const resp = await authFetch(
				buildProjectUrl("/api/visualizer", projectCwd),
			);
			if (!resp.ok) {
				const body = await resp
					.json()
					.catch(() => ({ error: "Unknown error" }));
				throw new Error(body.error || `HTTP ${resp.status}`);
			}
			const json: VisualizerData = await resp.json();
			setData(json);
			setError(null);
		} catch (err) {
			setError(
				err instanceof Error ? err.message : "Failed to fetch visualizer data",
			);
		} finally {
			setLoading(false);
		}
	}, [projectCwd]);

	useEffect(() => {
		// eslint-disable-next-line react-hooks/set-state-in-effect -- async fetch, setState runs after await
		fetchData();
		const interval = setInterval(fetchData, 10_000);
		return () => clearInterval(interval);
	}, [fetchData]);

	// Loading
	if (loading && !data) {
		return (
			<div className="flex h-full items-center justify-center">
				<div className="flex flex-col items-center gap-4">
					<Loader2 className="h-7 w-7 animate-spin text-muted-foreground" />
					<p className="text-sm text-muted-foreground">
						Loading visualizer data…
					</p>
				</div>
			</div>
		);
	}

	// Error (no cached data)
	if (error && !data) {
		return (
			<div className="flex h-full items-center justify-center">
				<div className="flex flex-col items-center gap-4 text-center">
					<div className="rounded-full border border-warning/20 bg-warning/10 p-4">
						<AlertTriangle className="h-6 w-6 text-warning" />
					</div>
					<div>
						<p className="text-sm font-semibold">Failed to load visualizer</p>
						<p className="mt-1.5 max-w-sm text-xs text-muted-foreground">
							{error}
						</p>
					</div>
					<button
						type="button"
						onClick={fetchData}
						className="mt-1 inline-flex items-center gap-2 rounded-lg border border-border bg-card px-4 py-2 text-sm font-medium transition-colors hover:bg-accent"
					>
						<RotateCcw className="h-3.5 w-3.5" />
						Retry
					</button>
				</div>
			</div>
		);
	}

	if (!data) return null;

	return (
		<div className="flex h-full flex-col overflow-hidden">
			{/* Header */}
			<div className="flex shrink-0 items-center justify-between border-b border-border px-7 py-5">
				<div>
					<h1 className="text-xl font-bold tracking-tight">
						Workflow Visualizer
					</h1>
					<div className="mt-1.5 flex items-center gap-3 text-sm text-muted-foreground">
						<span>
							Phase:{" "}
							<span
								className={cn(
									"inline-flex items-center rounded-md px-2 py-0.5 text-xs font-semibold uppercase tracking-wider",
									data.phase === "complete"
										? "bg-success/15 text-success"
										: data.phase === "active" || data.phase === "running"
											? "bg-info/15 text-info"
											: "bg-muted text-muted-foreground",
								)}
							>
								{data.phase}
							</span>
						</span>
						{data.remainingSliceCount > 0 && (
							<>
								<span className="text-border">·</span>
								<span>
									{data.remainingSliceCount} slice
									{data.remainingSliceCount !== 1 ? "s" : ""} remaining
								</span>
							</>
						)}
						{error && (
							<>
								<span className="text-border">·</span>
								<span className="flex items-center gap-1 text-warning">
									<AlertTriangle className="h-3 w-3" />
									Stale — {error}
								</span>
							</>
						)}
					</div>
				</div>
			</div>

			{/* Tabs */}
			<VisualizerTabs defaultValue="progress">
				<VisualizerTabList />

				<div className="flex-1 overflow-y-auto">
					<div className="mx-auto max-w-5xl px-7 py-7">
						<TabsPrimitive.Content value="progress" className="outline-none">
							<ProgressTab data={data} />
						</TabsPrimitive.Content>
						<TabsPrimitive.Content value="deps" className="outline-none">
							<DepsTab data={data} />
						</TabsPrimitive.Content>
						<TabsPrimitive.Content value="metrics" className="outline-none">
							<MetricsTab data={data} />
						</TabsPrimitive.Content>
						<TabsPrimitive.Content value="timeline" className="outline-none">
							<TimelineTab data={data} />
						</TabsPrimitive.Content>
						<TabsPrimitive.Content value="agent" className="outline-none">
							<AgentTab data={data} />
						</TabsPrimitive.Content>
						<TabsPrimitive.Content value="changes" className="outline-none">
							<ChangesTab data={data} />
						</TabsPrimitive.Content>
						<TabsPrimitive.Content value="export" className="outline-none">
							<ExportTab data={data} />
						</TabsPrimitive.Content>
					</div>
				</div>
			</VisualizerTabs>
		</div>
	);
}