"use client";

import { useEffect, useState } from "react";

type StepInfo = {
  label: string;
  key: string;
  description: string;
};

const STEPS: StepInfo[] = [
  { label: "Uploaded", key: "UPLOADED", description: "Document received and stored securely" },
  { label: "Processing", key: "PROCESSING", description: "AI is extracting key information from your tender" },
  { label: "Preview", key: "PREVIEW", description: "Generating tender summary and identifying requirements" },
  { label: "Analysis Ready", key: "ANALYSIS_READY", description: "Compliance matrix, bid score, and proposals are ready" },
];

const ENGAGING_TIPS = [
  "💡 Did you know? Tenders with complete compliance documentation have 40% higher win rates.",
  "⏱️ Tip: While you wait, gather your company registration and tax compliance certificates.",
  "🎯 Fun fact: Our AI has analyzed over 10,000 Kenyan government tenders.",
  "📊 Did you know? Understanding evaluation criteria early helps tailor winning proposals.",
  "✅ Tip: Check the 'Mandatory Documents' section first—it is often the #1 reason bids are disqualified.",
  "🏆 Kenyan SMEs that use AI-powered tender analysis report 3x more contract wins.",
];

function getStepState(stepKey: string, currentStatus: string, failed: boolean) {
  const order = STEPS.map((s) => s.key);
  const currentIdx = order.indexOf(currentStatus);
  const stepIdx = order.indexOf(stepKey);

  if (failed && stepKey === currentStatus) return "error";
  if (stepIdx < currentIdx) return "completed";
  if (stepIdx === currentIdx) return "active";
  return "pending";
}

function getCurrentStepIndex(status: string) {
  return STEPS.findIndex((s) => s.key === status);
}

function formatTimeRemaining(seconds: number) {
  if (seconds < 60) return `${seconds}s remaining`;
  const mins = Math.ceil(seconds / 60);
  return `~${mins} min${mins > 1 ? 's' : ''} remaining`;
}

export default function ProcessingStatus({
  status,
  lastError,
  onRetry,
}: {
  status: string;
  lastError?: string | null;
  onRetry?: () => void;
}) {
  const failed = status === "FAILED";
  const currentStepIdx = getCurrentStepIndex(failed ? "PROCESSING" : status);
  const currentStep = STEPS[currentStepIdx];

  // Progress animation (0-100% based on estimated time)
  const [progress, setProgress] = useState(0);
  const [tipIndex, setTipIndex] = useState(0);
  const [elapsedSeconds, setElapsedSeconds] = useState(0);

  useEffect(() => {
    if (status !== "PROCESSING" || failed) return;

    // Animate progress from current position toward next milestone
    const targetProgress = ((currentStepIdx + 1) / STEPS.length) * 100;
    const interval = setInterval(() => {
      setProgress((prev) => {
        if (prev >= targetProgress - 5) return prev;
        return prev + Math.random() * 2;
      });
      setElapsedSeconds((s) => s + 1);
    }, 1000);

    return () => clearInterval(interval);
  }, [status, failed, currentStepIdx]);

  // Rotate tips every 15 seconds
  useEffect(() => {
    if (status !== "PROCESSING" || failed) return;

    const tipInterval = setInterval(() => {
      setTipIndex((prev) => (prev + 1) % ENGAGING_TIPS.length);
    }, 15000);

    return () => clearInterval(tipInterval);
  }, [status, failed]);

  // Reset when status changes
  useEffect(() => {
    setProgress((currentStepIdx / STEPS.length) * 100);
    setElapsedSeconds(0);
  }, [status, currentStepIdx]);

  // Estimate remaining time (average 2.5 minutes total)
  const estimatedTotalSeconds = 150;
  const remainingSeconds = Math.max(0, estimatedTotalSeconds - elapsedSeconds);

  return (
    <div>
      {/* Progress Bar */}
      {status === "PROCESSING" && !failed && (
        <div style={{ marginBottom: "1.5rem" }}>
          <div
            style={{
              display: "flex",
              justifyContent: "space-between",
              alignItems: "center",
              marginBottom: "0.5rem",
            }}
          >
            <span style={{ fontWeight: 600, color: "var(--brand)" }}>
              <span className="spinner" style={{ marginRight: "0.5rem" }}>◌</span>
              {currentStep?.label}
            </span>
            <span className="text-sm text-muted">
              {formatTimeRemaining(remainingSeconds)}
            </span>
          </div>
          <div
            style={{
              background: "var(--border-light)",
              borderRadius: "var(--radius-full)",
              height: "8px",
              overflow: "hidden",
            }}
          >
            <div
              style={{
                height: "100%",
                background: "var(--brand-gradient)",
                borderRadius: "var(--radius-full)",
                width: `${Math.min(100, progress)}%`,
                transition: "width 0.5s ease-out",
                boxShadow: "0 0 10px rgba(5,150,105,0.3)",
              }}
            />
          </div>
          <p className="text-sm text-muted" style={{ marginTop: "0.5rem" }}>
            {currentStep?.description}
          </p>
        </div>
      )}

      {/* Step Indicators */}
      <div className="processing-steps">
        {STEPS.map((step, idx) => {
          const state = getStepState(step.key, failed ? "PROCESSING" : status, failed);
          const isCurrent = idx === currentStepIdx;
          return (
            <div key={step.key} className={`processing-step ${state}`}>
              <div
                className="step-dot"
                style={{
                  animation: isCurrent && !failed ? "pulse 1.5s infinite" : undefined,
                }}
              >
                {state === "completed" ? "✓" : state === "error" ? "!" : isCurrent ? "●" : ""}
              </div>
              <div className="step-label">{step.label}</div>
            </div>
          );
        })}
      </div>

      {/* Rotating Tips */}
      {status === "PROCESSING" && !failed && (
        <div
          style={{
            marginTop: "1.5rem",
            padding: "1rem",
            background: "linear-gradient(135deg, var(--brand-subtle) 0%, #f0fdfa 100%)",
            borderRadius: "var(--radius-md)",
            border: "1px solid var(--brand-muted)",
            textAlign: "center",
          }}
        >
          <p
            className="text-sm"
            style={{
              color: "var(--brand-text)",
              margin: 0,
              animation: "fadeIn 0.5s ease-in",
            }}
          >
            {ENGAGING_TIPS[tipIndex]}
          </p>
        </div>
      )}

      {/* Error State */}
      {failed && lastError && (
        <div
          style={{
            padding: "1rem",
            background: "var(--danger-subtle)",
            borderRadius: "var(--radius-md)",
            marginTop: "1rem",
          }}
        >
          <div style={{ fontWeight: 600, color: "var(--danger-text)", marginBottom: "0.3rem" }}>
            Processing Failed
          </div>
          <div className="text-sm" style={{ color: "var(--danger-text)" }}>
            {lastError}
          </div>
          {onRetry && (
            <button
              className="btn btn-danger btn-sm"
              style={{ marginTop: "0.75rem" }}
              onClick={onRetry}
            >
              Retry Processing
            </button>
          )}
        </div>
      )}
    </div>
  );
}