import { useState, useRef } from "react";

const SYSTEM_PROMPT = `You are a scholarship program communications specialist. Generate exactly three deadline reminder emails (30-day, 7-day, 48-hour) based on the inputs provided. Each email must be under 120 words (body text only, not counting subject line). Tone: 30-day = informational and welcoming; 7-day = warm and encouraging; 48-hour = urgent and action-oriented. Do NOT use em-dashes. Be human, not corporate. Return ONLY a valid JSON object with no markdown, no backticks, no explanation. Use this exact structure:
{
  "thirty": { "subject": "...", "body": "..." },
  "seven": { "subject": "...", "body": "..." },
  "fortyeight": { "subject": "...", "body": "..." }
}`;

function buildUserPrompt(program, deadline, link) {
  return `Program name: ${program}
Application deadline: ${deadline}
Application link: ${link}

Generate the three email drafts now.`;
}

function countWords(text) {
  return text.trim().split(/\s+/).filter(Boolean).length;
}

const LABELS = [
  { key: "thirty", days: "30 Days Out", color: "#1a5c8a", badge: "INFORMATIONAL", icon: "📅" },
  { key: "seven", days: "7 Days Out", color: "#c07a00", badge: "ENCOURAGING", icon: "⏳" },
  { key: "fortyeight", days: "48 Hours Out", color: "#b3000c", badge: "URGENT", icon: "🚨" },
];

export default function EmailGenerator() {
  const [program, setProgram] = useState("");
  const [deadline, setDeadline] = useState("");
  const [link, setLink] = useState("");
  const [emails, setEmails] = useState(null);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState("");
  const [copied, setCopied] = useState({});
  const abortRef = useRef(null);

  async function generate() {
    if (!program.trim() || !deadline || !link.trim()) {
      setError("Please fill in all three fields.");
      return;
    }
    setError("");
    setEmails(null);
    setLoading(true);

    try {
      const res = await fetch("https://api.anthropic.com/v1/messages", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          model: "claude-sonnet-4-20250514",
          max_tokens: 1000,
          system: SYSTEM_PROMPT,
          messages: [{ role: "user", content: buildUserPrompt(program, deadline, link) }],
        }),
      });
      const data = await res.json();
      const raw = data?.content?.find(b => b.type === "text")?.text || "";
      const parsed = JSON.parse(raw);
      setEmails(parsed);
    } catch (e) {
      setError("Generation failed. Check your inputs and try again.");
    } finally {
      setLoading(false);
    }
  }

  function copyEmail(key, subject, body) {
    const text = `Subject: ${subject}\n\n${body}`;
    navigator.clipboard.writeText(text).then(() => {
      setCopied(c => ({ ...c, [key]: true }));
      setTimeout(() => setCopied(c => ({ ...c, [key]: false })), 2000);
    });
  }

  function formatDeadlineDisplay(dateStr) {
    if (!dateStr) return "";
    const d = new Date(dateStr + "T12:00:00");
    return d.toLocaleDateString("en-US", { weekday: "long", year: "numeric", month: "long", day: "numeric" });
  }

  return (
    <div style={{ fontFamily: "'Georgia', 'Times New Roman', serif", minHeight: "100vh", background: "#f5f3ef", padding: "0" }}>
      {/* Header */}
      <div style={{ background: "#0d2d4e", color: "#fff", padding: "28px 32px 22px", borderBottom: "4px solid #c9a227" }}>
        <div style={{ maxWidth: 780, margin: "0 auto" }}>
          <div style={{ fontSize: 11, letterSpacing: "0.18em", color: "#c9a227", fontFamily: "sans-serif", textTransform: "uppercase", marginBottom: 6 }}>
            Scholarship Communications Tool
          </div>
          <h1 style={{ margin: 0, fontSize: 26, fontWeight: 700, lineHeight: 1.2, letterSpacing: "-0.01em" }}>
            Deadline Reminder Email Generator
          </h1>
          <p style={{ margin: "8px 0 0", fontSize: 14, color: "#b8ccd8", fontFamily: "sans-serif", fontWeight: 400 }}>
            Enter three inputs. Get three ready-to-send reminder emails.
          </p>
        </div>
      </div>

      <div style={{ maxWidth: 780, margin: "0 auto", padding: "32px 24px" }}>
        {/* Input card */}
        <div style={{ background: "#fff", border: "1px solid #ddd", borderRadius: 6, padding: "28px 28px 24px", marginBottom: 28, boxShadow: "0 1px 4px rgba(0,0,0,0.06)" }}>
          <div style={{ display: "grid", gridTemplateColumns: "1fr 1fr", gap: "18px 24px" }}>
            <div style={{ gridColumn: "1 / -1" }}>
              <label style={labelStyle}>Program Name</label>
              <input
                style={inputStyle}
                placeholder="e.g., Bright Future Scholarship"
                value={program}
                onChange={e => setProgram(e.target.value)}
              />
            </div>
            <div>
              <label style={labelStyle}>Application Deadline</label>
              <input
                type="date"
                style={inputStyle}
                value={deadline}
                onChange={e => setDeadline(e.target.value)}
              />
            </div>
            <div>
              <label style={labelStyle}>Application Link (URL)</label>
              <input
                style={inputStyle}
                placeholder="https://apply.example.org"
                value={link}
                onChange={e => setLink(e.target.value)}
              />
            </div>
          </div>

          {deadline && (
            <div style={{ marginTop: 14, fontSize: 12, color: "#555", fontFamily: "sans-serif", background: "#f0f4f8", borderRadius: 4, padding: "6px 12px", display: "inline-block" }}>
              Deadline: {formatDeadlineDisplay(deadline)}
            </div>
          )}

          {error && (
            <div style={{ marginTop: 14, color: "#9b1c1c", fontSize: 13, fontFamily: "sans-serif", background: "#fff0f0", border: "1px solid #fca5a5", borderRadius: 4, padding: "8px 12px" }}>
              {error}
            </div>
          )}

          <button
            onClick={generate}
            disabled={loading}
            style={{
              marginTop: 20,
              background: loading ? "#7a9db5" : "#0d2d4e",
              color: "#fff",
              border: "none",
              borderRadius: 4,
              padding: "12px 28px",
              fontSize: 14,
              fontFamily: "sans-serif",
              fontWeight: 600,
              letterSpacing: "0.04em",
              cursor: loading ? "not-allowed" : "pointer",
              display: "flex",
              alignItems: "center",
              gap: 8,
              transition: "background 0.15s",
            }}
          >
            {loading ? (
              <>
                <span style={{ display: "inline-block", width: 14, height: 14, border: "2px solid #fff", borderTopColor: "transparent", borderRadius: "50%", animation: "spin 0.7s linear infinite" }} />
                Generating emails...
              </>
            ) : (
              "Generate 3-Email Sequence"
            )}
          </button>
        </div>

        {/* Email output */}
        {emails && (
          <div style={{ display: "flex", flexDirection: "column", gap: 20 }}>
            {LABELS.map(({ key, days, color, badge, icon }) => {
              const email = emails[key];
              if (!email) return null;
              const wc = countWords(email.body);
              const over = wc > 120;
              return (
                <div
                  key={key}
                  style={{
                    background: "#fff",
                    border: `1px solid #ddd`,
                    borderLeft: `5px solid ${color}`,
                    borderRadius: 6,
                    overflow: "hidden",
                    boxShadow: "0 1px 4px rgba(0,0,0,0.06)",
                  }}
                >
                  {/* Email header */}
                  <div style={{ background: "#fafafa", borderBottom: "1px solid #eee", padding: "12px 20px", display: "flex", alignItems: "center", justifyContent: "space-between", gap: 12 }}>
                    <div style={{ display: "flex", alignItems: "center", gap: 10 }}>
                      <span style={{ fontSize: 18 }}>{icon}</span>
                      <div>
                        <div style={{ fontFamily: "sans-serif", fontWeight: 700, fontSize: 14, color: "#111" }}>{days}</div>
                        <div style={{
                          display: "inline-block",
                          fontSize: 10,
                          fontFamily: "sans-serif",
                          fontWeight: 700,
                          letterSpacing: "0.12em",
                          color,
                          background: `${color}18`,
                          border: `1px solid ${color}44`,
                          borderRadius: 3,
                          padding: "2px 7px",
                          marginTop: 2,
                        }}>{badge}</div>
                      </div>
                    </div>
                    <div style={{ display: "flex", alignItems: "center", gap: 10 }}>
                      <span style={{ fontFamily: "sans-serif", fontSize: 12, color: over ? "#9b1c1c" : "#4a7c59", fontWeight: 600 }}>
                        {wc} words {over ? "(⚠ over 120)" : "✓"}
                      </span>
                      <button
                        onClick={() => copyEmail(key, email.subject, email.body)}
                        style={{
                          background: copied[key] ? "#2F5F8F" : "#0d2d4e",
                          color: "#fff",
                          border: "none",
                          borderRadius: 4,
                          padding: "7px 16px",
                          fontSize: 12,
                          fontFamily: "sans-serif",
                          fontWeight: 600,
                          cursor: "pointer",
                          letterSpacing: "0.03em",
                          transition: "background 0.15s",
                          minWidth: 80,
                        }}
                      >
                        {copied[key] ? "Copied!" : "Copy"}
                      </button>
                    </div>
                  </div>

                  {/* Email content */}
                  <div style={{ padding: "18px 20px" }}>
                    <div style={{ marginBottom: 12 }}>
                      <span style={{ fontFamily: "sans-serif", fontSize: 11, fontWeight: 700, color: "#777", letterSpacing: "0.1em", textTransform: "uppercase" }}>Subject</span>
                      <div style={{ marginTop: 4, fontFamily: "sans-serif", fontSize: 14, color: "#111", fontWeight: 600, background: "#f5f3ef", padding: "8px 12px", borderRadius: 4, border: "1px solid #e5e2db" }}>
                        {email.subject}
                      </div>
                    </div>
                    <div>
                      <span style={{ fontFamily: "sans-serif", fontSize: 11, fontWeight: 700, color: "#777", letterSpacing: "0.1em", textTransform: "uppercase" }}>Body</span>
                      <div style={{ marginTop: 4, fontSize: 14, color: "#222", lineHeight: 1.7, whiteSpace: "pre-wrap", background: "#fcfbf9", padding: "14px 16px", borderRadius: 4, border: "1px solid #e5e2db" }}>
                        {email.body}
                      </div>
                    </div>
                  </div>
                </div>
              );
            })}

            {/* Footer note */}
            <div style={{ fontFamily: "sans-serif", fontSize: 12, color: "#666", background: "#f0f4f8", border: "1px solid #d0dce8", borderRadius: 4, padding: "10px 16px", lineHeight: 1.6 }}>
              <strong>Before sending:</strong> Personalize salutations, confirm the deadline date is accurate, verify the application link resolves, and have a staff member approve each draft.
            </div>
          </div>
        )}
      </div>

      <style>{`
        @keyframes spin { to { transform: rotate(360deg); } }
        input:focus { outline: 2px solid #0d2d4e; outline-offset: 1px; }
        button:hover:not(:disabled) { filter: brightness(1.12); }
      `}</style>
    </div>
  );
}

const labelStyle = {
  display: "block",
  fontFamily: "sans-serif",
  fontSize: 12,
  fontWeight: 700,
  color: "#444",
  letterSpacing: "0.06em",
  textTransform: "uppercase",
  marginBottom: 6,
};

const inputStyle = {
  width: "100%",
  boxSizing: "border-box",
  fontFamily: "sans-serif",
  fontSize: 14,
  color: "#111",
  background: "#fafafa",
  border: "1px solid #ccc",
  borderRadius: 4,
  padding: "9px 12px",
  transition: "border-color 0.15s",
};