"use client";

import { useEffect, useState } from "react";
import { useTenant } from "@/contexts/TenantContext";

type HeatmapData = {
  hour: number;
  day: number; // 0-6 (Sunday-Saturday)
  count: number;
};

type ToolUsageTrend = {
  tool: string;
  count: number;
  trend: "up" | "down" | "stable";
};

type TenantHeatmapProps = {
  days?: number;
};

const API_BASE =
  process.env.NEXT_PUBLIC_API_URL?.replace(/\/$/, "") || "http://localhost:8000";

const DAYS = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
const HOURS = Array.from({ length: 24 }, (_, i) => i);

export function TenantHeatmap({ days = 7 }: TenantHeatmapProps) {
  const { tenantId, role } = useTenant();
  const [loading, setLoading] = useState(false);
  const [heatmapData, setHeatmapData] = useState<HeatmapData[]>([]);
  const [toolTrends, setToolTrends] = useState<ToolUsageTrend[]>([]);
  const [maxCount, setMaxCount] = useState(1);

  useEffect(() => {
    async function fetchHeatmapData() {
      if (!tenantId) return;

      setLoading(true);
      try {
        // Fetch activity data
        const activityRes = await fetch(
          `${API_BASE}/analytics/activity?days=${days}`,
          {
            headers: {
              "x-tenant-id": tenantId,
              "x-user-role": role,
            },
          },
        );

        if (!activityRes.ok) {
          throw new Error(`Activity endpoint returned ${activityRes.status}`);
        }

        const activityData = await activityRes.json();

        // Fetch tool usage stats
        const toolRes = await fetch(
          `${API_BASE}/analytics/tool-usage?days=${days}`,
          {
            headers: {
              "x-tenant-id": tenantId,
              "x-user-role": role,
            },
          },
        );

        if (!toolRes.ok) {
          throw new Error(`Tool usage endpoint returned ${toolRes.status}`);
        }

        const toolData = await toolRes.json();

        // Process activity data into heatmap format
        const heatmap: HeatmapData[] = [];
        const activityByHour: Record<string, number> = {};

        // Group activities by hour and day
        if (activityData.activities && Array.isArray(activityData.activities)) {
          activityData.activities.forEach((activity: any) => {
            try {
              const timestamp = new Date(activity.timestamp || activity.created_at);
              // Check if date is valid
              if (!isNaN(timestamp.getTime())) {
                const hour = timestamp.getHours();
                const day = timestamp.getDay();
                const key = `${day}-${hour}`;

                activityByHour[key] = (activityByHour[key] || 0) + 1;
              }
            } catch (e) {
              // Skip invalid timestamps
              console.warn("Invalid timestamp in activity:", activity);
            }
          });
        }

        // Build heatmap data
        for (let day = 0; day < 7; day++) {
          for (let hour = 0; hour < 24; hour++) {
            const key = `${day}-${hour}`;
            const count = activityByHour[key] || 0;
            heatmap.push({ hour, day, count });
          }
        }

        setHeatmapData(heatmap);
        setMaxCount(Math.max(...heatmap.map((h) => h.count), 1));

        // Process tool trends
        const trends: ToolUsageTrend[] = [];
        if (toolData.tool_usage) {
          Object.entries(toolData.tool_usage).forEach(([tool, stats]: [string, any]) => {
            trends.push({
              tool,
              count: stats.count || 0,
              trend: "stable", // Could be calculated from historical data
            });
          });
        }

        // Sort by count descending
        trends.sort((a, b) => b.count - a.count);
        setToolTrends(trends.slice(0, 10)); // Top 10 tools
      } catch (err) {
        console.error("Failed to fetch heatmap data:", err);
        // Set empty data on error to show empty state
        setHeatmapData([]);
        setToolTrends([]);
        setMaxCount(1);
      } finally {
        setLoading(false);
      }
    }

    fetchHeatmapData();
  }, [tenantId, role, days]);

  const getIntensity = (count: number) => {
    if (maxCount === 0) return 0;
    const ratio = count / maxCount;
    if (ratio === 0) return 0;
    if (ratio < 0.2) return 1;
    if (ratio < 0.4) return 2;
    if (ratio < 0.6) return 3;
    if (ratio < 0.8) return 4;
    return 5;
  };

  const getColorClass = (intensity: number) => {
    const colors = [
      "bg-slate-800/30 border-slate-700/30", // 0
      "bg-cyan-500/20 border-cyan-500/30", // 1
      "bg-cyan-500/40 border-cyan-500/50", // 2
      "bg-cyan-500/60 border-cyan-500/70", // 3
      "bg-cyan-500/80 border-cyan-500/90", // 4
      "bg-cyan-500 border-cyan-400", // 5
    ];
    return colors[intensity] || colors[0];
  };

  return (
    <div className="space-y-6">
      {/* Query Heatmap */}
      <div className="rounded-2xl border border-white/10 bg-slate-950/40 p-6">
        <div className="mb-4 flex items-center justify-between">
          <h3 className="text-lg font-semibold text-white">Query Activity Heatmap</h3>
          <span className="text-xs text-slate-400">Last {days} days</span>
        </div>

        {loading ? (
          <div className="flex h-64 items-center justify-center">
            <span className="text-slate-400">Loading heatmap data...</span>
          </div>
        ) : (
          <div className="overflow-x-auto">
            <div className="inline-block min-w-full">
              {/* Hour labels */}
              <div className="mb-2 flex">
                <div className="w-12 shrink-0" />
                {HOURS.map((hour) => (
                  <div
                    key={hour}
                    className="flex-1 text-center text-[10px] text-slate-500"
                  >
                    {hour % 6 === 0 ? hour : ""}
                  </div>
                ))}
              </div>

              {/* Heatmap grid */}
              <div className="space-y-1">
                {DAYS.map((dayName, dayIdx) => {
                  const dayData = heatmapData.filter((d) => d.day === dayIdx);
                  return (
                    <div key={dayIdx} className="flex items-center gap-2">
                      <div className="w-12 shrink-0 text-xs text-slate-400">
                        {dayName}
                      </div>
                      <div className="flex flex-1 gap-0.5">
                        {HOURS.map((hour) => {
                          const data = dayData.find((d) => d.hour === hour);
                          const count = data?.count || 0;
                          const intensity = getIntensity(count);

                          return (
                            <div
                              key={hour}
                              className={`h-4 flex-1 rounded border transition-all hover:scale-110 ${getColorClass(
                                intensity,
                              )}`}
                              title={`${dayName} ${hour}:00 - ${count} queries`}
                            />
                          );
                        })}
                      </div>
                    </div>
                  );
                })}
              </div>

              {/* Legend */}
              <div className="mt-4 flex items-center justify-center gap-4 text-xs text-slate-400">
                <span>Less</span>
                <div className="flex gap-0.5">
                  {[0, 1, 2, 3, 4, 5].map((intensity) => (
                    <div
                      key={intensity}
                      className={`h-3 w-3 rounded border ${getColorClass(intensity)}`}
                    />
                  ))}
                </div>
                <span>More</span>
              </div>
            </div>
          </div>
        )}
      </div>

      {/* Tool Usage Trends */}
      <div className="rounded-2xl border border-white/10 bg-slate-950/40 p-6">
        <div className="mb-4 flex items-center justify-between">
          <h3 className="text-lg font-semibold text-white">Per-Tool Usage Trends</h3>
          <span className="text-xs text-slate-400">Top 10 tools</span>
        </div>

        {loading ? (
          <div className="flex h-32 items-center justify-center">
            <span className="text-slate-400">Loading tool trends...</span>
          </div>
        ) : toolTrends.length === 0 ? (
          <div className="flex h-32 items-center justify-center">
            <span className="text-slate-400">No tool usage data available</span>
          </div>
        ) : (
          <div className="space-y-3">
            {toolTrends.map((trend, idx) => {
              const maxToolCount = Math.max(...toolTrends.map((t) => t.count), 1);
              const widthPercent = (trend.count / maxToolCount) * 100;

              return (
                <div key={idx} className="space-y-1">
                  <div className="flex items-center justify-between text-sm">
                    <div className="flex items-center gap-2">
                      <span className="font-medium text-white">{trend.tool}</span>
                      {trend.trend === "up" && (
                        <span className="text-xs text-emerald-400">↑</span>
                      )}
                      {trend.trend === "down" && (
                        <span className="text-xs text-red-400">↓</span>
                      )}
                    </div>
                    <span className="text-slate-300">{trend.count}</span>
                  </div>
                  <div className="h-2 overflow-hidden rounded-full bg-slate-800">
                    <div
                      className="h-full bg-gradient-to-r from-cyan-500 to-cyan-400 transition-all"
                      style={{ width: `${widthPercent}%` }}
                    />
                  </div>
                </div>
              );
            })}
          </div>
        )}
      </div>
    </div>
  );
}