import { senderDisplayName } from "./senderAvatar";

const CATEGORY_ORDER = ["Primary", "Updates", "Promotions", "Social", "Finance"];

export function emailSearchText(email) {
  const sender = typeof email.sender === "string"
    ? email.sender
    : email.sender?.name || email.sender?.email || email.sender?.address || "";
  return [
    sender,
    email.subject,
    email.snippet,
    email.preview,
    email.body_text,
  ].filter(Boolean).join(" ").toLowerCase();
}

export function emailCategory(email) {
  const text = emailSearchText(email);
  if (/invoice|bill|payment|receipt|finance|bank|transfer|otp|wallet/.test(text)) return "Finance";
  if (/linkedin|twitter|facebook|instagram|connection request|social/.test(text)) return "Social";
  if (/unsubscribe|promo|offer|sale|newsletter|deal|discount/.test(text)) return "Promotions";
  if (/notification|update|alert|noreply|no-reply|provisioned|activated|console|security/.test(text)) return "Updates";
  return "Primary";
}

const PRIORITY_LABELS = new Set(["Important", "Clients", "Projects", "Finance", "HR"]);
const ACTION_LABELS = new Set(["Clients", "Important", "Projects", "Finance", "HR", "AI"]);

export function emailLabels(email) {
  const text = emailSearchText(email);
  const labels = [];
  if (email.is_starred || /urgent|important|asap|priority/.test(text)) {
    labels.push({ name: "Important", tone: "rose" });
  }
  if (/project|proposal|website|development|sow|contract/.test(text)) {
    labels.push({ name: "Projects", tone: "violet" });
  }
  if (/client|customer|internship|candidate|revdau|desi clans/.test(text)) {
    labels.push({ name: "Clients", tone: "blue" });
  }
  if (/hr|hiring|recruit|offer letter|onboarding/.test(text)) {
    labels.push({ name: "HR", tone: "violet" });
  }
  if (/invoice|bill|payment|finance|receipt/.test(text)) {
    labels.push({ name: "Finance", tone: "amber" });
  }
  if (/integration|api|webhook|connect/.test(text)) {
    labels.push({ name: "Integrations", tone: "green" });
  }
  if (/ai|agent|llm|gpt|model/.test(text)) {
    labels.push({ name: "AI", tone: "pink" });
  }
  if (/domain|dns|mx|spf|dkim|\.env|environment variable/.test(text)) {
    labels.push({ name: "Domains", tone: "amber" });
  }
  if (/linkedin|twitter|facebook|instagram|social/.test(text)) {
    labels.push({ name: "Social", tone: "green" });
  }
  if (/notification|update|alert|noreply|security/.test(text)) {
    labels.push({ name: "Updates", tone: "blue" });
  }
  if (/personal|family/.test(text)) {
    labels.push({ name: "Personal", tone: "green" });
  }
  const unique = [];
  labels.forEach((label) => {
    if (!unique.some((item) => item.name === label.name)) unique.push(label);
  });
  return unique.slice(0, 2);
}

export function matchesLens(email, lens) {
  if (!lens || lens === "all") return true;
  if (lens === "starred") return email.is_starred === true;
  return emailLabels(email).some((label) => label.name === lens);
}

export function categoryCounts(emails) {
  const counts = Object.fromEntries(CATEGORY_ORDER.map((name) => [name, 0]));
  emails.forEach((email) => {
    if (email.is_read === false) counts[emailCategory(email)] += 1;
  });
  return counts;
}

function hasPriorityLabel(email) {
  return emailLabels(email).some((label) => PRIORITY_LABELS.has(label.name));
}

function hasActionLabel(email) {
  return emailLabels(email).some((label) => ACTION_LABELS.has(label.name));
}

function looksActionable(email) {
  const text = emailSearchText(email);
  return /please|action|reply|review|attached|confirm|need|waiting|\?|follow up|response/.test(text)
    || attachmentCount(email) > 0
    || /https?:\/\//.test(text);
}

export function inboxIntelligence(emails) {
  const unread = emails.filter((email) => email.is_read === false);
  const important = emails.filter((email) =>
    email.is_starred
    || email.is_read === false
    || hasPriorityLabel(email)
    || emailLabels(email).length > 0,
  );
  const actionItems = emails.filter((email) =>
    looksActionable(email) || hasActionLabel(email) || email.is_read === false,
  );
  const meetings = emails.filter((email) =>
    /meet|meeting|calendar|schedule|call|zoom|interview|sync|demo|standup/.test(emailSearchText(email)),
  );
  const invoices = emails.filter((email) =>
    /invoice|bill|payment|receipt|purchase order|\bpo\b/.test(emailSearchText(email)),
  );
  return {
    unread: unread.length,
    important: important.length,
    actionItems: actionItems.length,
    meetings: meetings.length,
    invoices: invoices.length,
    importantFromClients: important.filter((email) =>
      emailLabels(email).some((label) => label.name === "Clients"),
    ).length,
  };
}

export function attachmentCount(email) {
  if (Array.isArray(email.attachments)) return email.attachments.length;
  return Number(email.attachment_count || 0);
}

function emailTimestamp(email) {
  const value = email.received_at || email.sent_at || email.created_at || email.updated_at;
  if (!value) return null;
  const date = new Date(value);
  return Number.isNaN(date.getTime()) ? null : date;
}

function formatRelativeAge(date) {
  if (!date) return "";
  const hours = Math.floor((Date.now() - date.getTime()) / 3600000);
  if (hours < 1) return "<1h";
  if (hours < 24) return `${hours}h`;
  return `${Math.floor(hours / 24)}d`;
}

function extractMeetingTime(text) {
  const match = text.match(/\b(\d{1,2}:\d{2})\s*(am|pm)?/i)
    || text.match(/\b(\d{1,2})\s*(am|pm)\b/i);
  if (!match) return null;
  const raw = match[0].replace(/\s+/g, " ").trim();
  if (/am|pm/i.test(raw)) return raw.toUpperCase();
  const [hours, minutes] = raw.split(":").map(Number);
  if (Number.isNaN(hours)) return raw;
  const period = hours >= 12 ? "PM" : "AM";
  const hour12 = hours % 12 || 12;
  return `${hour12}:${String(minutes || 0).padStart(2, "0")} ${period}`;
}

function extractVenue(text) {
  if (/google meet|meet\.google/i.test(text)) return "Google Meet";
  if (/zoom/i.test(text)) return "Zoom";
  if (/teams|microsoft teams/i.test(text)) return "Teams";
  if (/video call|video meeting/i.test(text)) return "Video call";
  return "";
}

function extractReplyStatus(text) {
  if (/confirm|confirmation|awaiting/.test(text)) return "Awaiting confirmation";
  if (/proposal|quote/.test(text)) return "Proposal reply";
  if (/invoice|payment|bill/.test(text)) return "Payment follow-up";
  if (/review|feedback/.test(text)) return "Needs review";
  if (/reply|respond/.test(text)) return "Needs reply";
  return "Needs attention";
}

function extractDeadline(text) {
  if (/tomorrow/i.test(text)) return "Tomorrow";
  const weekday = text.match(/\b(monday|tuesday|wednesday|thursday|friday|saturday|sunday)\b/i);
  if (weekday) {
    return weekday[1].charAt(0).toUpperCase() + weekday[1].slice(1);
  }
  if (/today/i.test(text)) return "Today";
  return null;
}

export function inboxContext(emails) {
  const stats = inboxIntelligence(emails);

  const needsReply = emails
    .filter((email) =>
      email.is_read === false
      || looksActionable(email)
      || hasActionLabel(email)
      || /please|reply|respond|confirm|review|attached|need your|waiting|action required/.test(
        emailSearchText(email),
      ),
    )
    .sort((left, right) => {
      const leftDate = emailTimestamp(left)?.getTime() || 0;
      const rightDate = emailTimestamp(right)?.getTime() || 0;
      return rightDate - leftDate;
    })
    .slice(0, 4)
    .map((email) => ({
      id: email.id,
      name: senderDisplayName(email),
      age: formatRelativeAge(emailTimestamp(email)),
      status: extractReplyStatus(emailSearchText(email)),
    }));

  const today = [];
  emails.forEach((email) => {
    const text = emailSearchText(email);
    if (!/meet|meeting|call|interview|sync|calendar/.test(text)) return;
    const time = extractMeetingTime(text);
    if (!time) return;
    const label = (email.subject || "Meeting").trim().slice(0, 42);
    const venue = extractVenue(text);
    const tone = /invoice|payment|bill|purchase order|\bpo\b/.test(text)
      ? "amber"
      : /sync|project/.test(text)
        ? "rose"
        : /client|demo/.test(text)
          ? "blue"
          : "green";
    if (!today.some((item) => item.time === time && item.label === label)) {
      today.push({ time, label, venue, tone });
    }
  });

  const deadlines = [];
  emails.forEach((email) => {
    const text = emailSearchText(email);
    if (!/invoice|proposal|payment|due|deadline|bill/.test(text)) return;
    const due = extractDeadline(text);
    if (!due) return;
    const label = (email.subject || "Deadline")
      .split(/[-–:|]/)
      .map((part) => part.trim())
      .find(Boolean)
      ?.slice(0, 28) || "Deadline";
    if (!deadlines.some((item) => item.label === label && item.due === due)) {
      deadlines.push({ label, due });
    }
  });

  return {
    stats,
    needsReply,
    today: today.slice(0, 4),
    deadlines: deadlines.slice(0, 4),
  };
}

export function labelCounts(emails) {
  const counts = {
    Important: 0,
    Projects: 0,
    Clients: 0,
    Finance: 0,
    Personal: 0,
  };
  emails.forEach((email) => {
    emailLabels(email).forEach((label) => {
      counts[label.name] = (counts[label.name] || 0) + 1;
    });
  });
  return counts;
}