import React, { useCallback, useEffect, useMemo, useRef, useState } from "react";
import { useNavigate, useSearchParams } from "react-router-dom";
import {
  Box,
  Alert,
  Chip,
  CircularProgress,
  FormControl,
  InputLabel,
  MenuItem,
  Paper,
  Select,
  Stack,
  TextField,
  Typography,
  Button,
} from "@mui/material";
import MailOutlineIcon from "@mui/icons-material/MailOutline";
import { api, getApiErrorMessage } from "../api";
import { useConfirm } from "../confirm";
import { useToast } from "../toast";
import GmailReviewPage from "./GmailReviewPage";

export type CorrespondenceInboxItem = {
  id: number;
  jobApplicationId: number;
  companyName?: string | null;
  jobTitle?: string | null;
  from: string;
  direction?: string | null;
  subject?: string | null;
  channel?: string | null;
  date: string;
  contentPreview: string;
  externalThreadId?: string | null;
  externalMessageId?: string | null;
  provider?: string | null;
  externalFrom?: string | null;
  externalTo?: string | null;
  labelCount: number;
  attachmentCount: number;
};

type EmailProviderStatus = {
  provider: string;
  displayName: string;
  connected: boolean;
  address?: string | null;
  canRead: boolean;
  canSend: boolean;
};

type JobChoice = {
  id: number;
  jobTitle: string;
  company?: { name?: string | null } | null;
};

export function emailProviderStatusLabel(provider: EmailProviderStatus) {
  if (!provider.connected) return `${provider.displayName}: Not connected`;
  const identity = provider.address || "Connected account";
  if (!provider.canRead) return `${provider.displayName}: ${identity} · Mailbox access unavailable`;
  return `${provider.displayName}: ${identity}${provider.canSend ? " · Read + send" : " · Read only; reconnect to enable send"}`;
}

type EmailMessageDetail = {
  id: string;
  threadId: string;
  subject: string;
  from: string;
  to: string;
  date?: string | null;
  snippet: string;
  bodyText: string;
  labels: string[];
  attachments: Array<{ fileName?: string | null; mimeType?: string | null; sizeBytes?: number | null }>;
};

type EmailDraft = {
  id?: string;
  revision?: number;
  jobApplicationId: number;
  companyName: string;
  jobTitle: string;
  provider: string;
  providerName: string;
  fromAddress: string;
  to: string;
  subject: string;
  bodyText: string;
  threadId: string;
  clientRequestId: string;
};

type StoredEmailDraft = Pick<EmailDraft, "id" | "revision" | "jobApplicationId" | "provider" | "to" | "subject" | "bodyText" | "threadId" | "clientRequestId"> & {
  id: string;
  revision: number;
  createdAtUtc: string;
  updatedAtUtc: string;
};

type EmailSendResult = {
  attemptId: string;
  status: "pending" | "sending" | "sent" | "failed" | "uncertain";
  duplicate: boolean;
  externalMessageId?: string | null;
  externalThreadId?: string | null;
  failureCategory?: string | null;
};

export default function CorrespondenceInboxPage() {
  const navigate = useNavigate();
  const [searchParams, setSearchParams] = useSearchParams();
  const view = searchParams.get("view") === "review" ? "review" : "inbox";
  const { toast } = useToast();
  const { confirm } = useConfirm();
  const [items, setItems] = useState<CorrespondenceInboxItem[]>([]);
  const [providers, setProviders] = useState<EmailProviderStatus[]>([]);
  const [providerStatusLoaded, setProviderStatusLoaded] = useState(false);
  const [jobs, setJobs] = useState<JobChoice[]>([]);
  const [jobsLoaded, setJobsLoaded] = useState(false);
  const [composeSetupOpen, setComposeSetupOpen] = useState(false);
  const [composeJobId, setComposeJobId] = useState<number | "">("");
  const [composeProvider, setComposeProvider] = useState("");
  const [providerStatusError, setProviderStatusError] = useState(false);
  const [selectedMessageId, setSelectedMessageId] = useState<number | null>(null);
  const [messageDetail, setMessageDetail] = useState<EmailMessageDetail | null>(null);
  const [detailLoading, setDetailLoading] = useState(false);
  const [detailError, setDetailError] = useState<string | null>(null);
  const [detailNotice, setDetailNotice] = useState<string | null>(null);
  const detailRequest = useRef(0);
  const [loading, setLoading] = useState(false);
  const [query, setQuery] = useState("");
  const [direction, setDirection] = useState<string>("all");
  const [linkState, setLinkState] = useState<string>("all");
  const [draft, setDraft] = useState<EmailDraft | null>(null);
  const [storedDrafts, setStoredDrafts] = useState<StoredEmailDraft[]>([]);
  const [savingDraft, setSavingDraft] = useState(false);
  const [draftError, setDraftError] = useState<string | null>(null);
  const [sendResult, setSendResult] = useState<EmailSendResult | null>(null);
  const [sendError, setSendError] = useState<string | null>(null);
  const [sending, setSending] = useState(false);
  const [unlinkingThreadId, setUnlinkingThreadId] = useState<string | null>(null);

  const load = useCallback(async () => {
    setLoading(true);
    try {
      const res = await api.get<CorrespondenceInboxItem[]>("/correspondence", {
        params: {
          q: query.trim() || undefined,
          direction: direction === "all" ? undefined : direction,
          linkState: linkState === "all" ? undefined : linkState,
        },
      });
      setItems(res.data ?? []);
    } catch (error) {
      toast(getApiErrorMessage(error, "Failed to load correspondence inbox."), "error");
    } finally {
      setLoading(false);
    }
  }, [direction, linkState, query, toast]);

  useEffect(() => {
    if (view === "inbox") void load();
  }, [load, view]);

  useEffect(() => {
    api.get<EmailProviderStatus[]>("/email/providers")
      .then((response) => {
        setProviders(response.data ?? []);
        setProviderStatusError(false);
      })
      .catch(() => {
        setProviders([]);
        setProviderStatusError(true);
      })
      .finally(() => setProviderStatusLoaded(true));
  }, []);

  useEffect(() => {
    api.get<{ items?: JobChoice[] }>("/jobapplications", { params: { page: 1, pageSize: 100, sortBy: "dateApplied", sortDir: "desc" } })
      .then((response) => setJobs(Array.isArray(response.data?.items) ? response.data.items : []))
      .catch(() => setJobs([]))
      .finally(() => setJobsLoaded(true));
  }, []);

  const loadStoredDrafts = useCallback(async () => {
    try {
      const response = await api.get<StoredEmailDraft[]>("/email/drafts");
      setStoredDrafts(Array.isArray(response.data) ? response.data : []);
    } catch {
      setDraftError("Saved drafts could not be loaded. New email can still be reviewed before sending.");
    }
  }, []);

  useEffect(() => {
    void loadStoredDrafts();
  }, [loadStoredDrafts]);

  const filteredSummary = useMemo(() => {
    const linked = items.filter((item) => item.externalThreadId).length;
    const inbound = items.filter((item) => item.direction === "inbound").length;
    return { linked, inbound };
  }, [items]);
  const sendCapableProviders = useMemo(() => providers.filter((provider) => provider.connected && provider.canSend), [providers]);

  const showMessage = async (item: CorrespondenceInboxItem) => {
    if (selectedMessageId === item.id) {
      detailRequest.current += 1;
      setSelectedMessageId(null);
      setMessageDetail(null);
      return;
    }

    const request = ++detailRequest.current;
    setSelectedMessageId(item.id);
    setMessageDetail(null);
    setDetailError(null);
    setDetailNotice(null);
    setDetailLoading(true);
    try {
      if (item.provider && item.provider !== "manual" && item.externalMessageId) {
        try {
          const live = await api.get<EmailMessageDetail>("/email/message", {
            params: { provider: item.provider, messageId: item.externalMessageId },
          });
          if (request !== detailRequest.current) return;
          setMessageDetail(live.data);
          return;
        } catch {
          if (request !== detailRequest.current) return;
          setDetailNotice("The provider copy is unavailable. Showing the saved JobTracker copy.");
        }
      }

      const saved = await api.get<EmailMessageDetail>(`/correspondence/message/${item.id}`);
      if (request !== detailRequest.current) return;
      setMessageDetail(saved.data);
    } catch (error) {
      if (request !== detailRequest.current) return;
      setDetailError(getApiErrorMessage(error, "Failed to load this message."));
    } finally {
      if (request === detailRequest.current) setDetailLoading(false);
    }
  };

  const startReply = async (item: CorrespondenceInboxItem) => {
    if (!messageDetail || !item.provider) return;
    const provider = providers.find((candidate) => candidate.provider === item.provider);
    if (!provider?.canSend) return;
    if (draft?.bodyText.trim() && !(await confirm({
      title: "Replace email draft?",
      message: "Starting this reply will discard the draft you are currently editing.",
      confirmLabel: "Replace draft",
      destructive: true,
    }))) return;
    const subject = messageDetail.subject.trim();
    setDraft({
      jobApplicationId: item.jobApplicationId,
      companyName: item.companyName || "Unknown company",
      jobTitle: item.jobTitle || "Unknown role",
      provider: item.provider,
      providerName: provider.displayName,
      fromAddress: provider.address || "Connected account",
      to: item.direction === "outbound" ? messageDetail.to : messageDetail.from,
      subject: /^re:/i.test(subject) ? subject : `Re: ${subject || "Your message"}`,
      bodyText: "",
      threadId: messageDetail.threadId || item.externalThreadId || "",
      clientRequestId: globalThis.crypto.randomUUID(),
    });
    setSendResult(null);
    setSendError(null);
    setDraftError(null);
  };

  const resumeDraft = async (stored: StoredEmailDraft) => {
    if (draft?.bodyText.trim() && !(await confirm({
      title: "Replace email draft?",
      message: draft.id ? "Your current draft is already saved and can be resumed later." : "Your current unsaved draft text will be lost.",
      confirmLabel: "Replace draft",
      destructive: !draft.id,
    }))) return;
    const provider = providers.find((candidate) => candidate.provider === stored.provider);
    const item = items.find((candidate) => candidate.jobApplicationId === stored.jobApplicationId);
    setDraft({
      ...stored,
      companyName: item?.companyName || `Job #${stored.jobApplicationId}`,
      jobTitle: item?.jobTitle || "Saved email draft",
      providerName: provider?.displayName || stored.provider,
      fromAddress: provider?.address || "Reconnect before sending",
    });
    setSendResult(null);
    setSendError(null);
    setDraftError(null);
  };

  const openComposeSetup = () => {
    setComposeJobId((current) => current || jobs[0]?.id || "");
    setComposeProvider((current) => current || sendCapableProviders[0]?.provider || "");
    setComposeSetupOpen(true);
  };

  const startNewMessage = async () => {
    const job = jobs.find((candidate) => candidate.id === composeJobId);
    const provider = sendCapableProviders.find((candidate) => candidate.provider === composeProvider);
    if (!job || !provider) return;
    if (draft?.bodyText.trim() && !(await confirm({
      title: "Replace email draft?",
      message: draft.id ? "Your current draft is already saved and can be resumed later." : "Your current unsaved draft text will be lost.",
      confirmLabel: "Replace draft",
      destructive: !draft.id,
    }))) return;
    setDraft({
      jobApplicationId: job.id,
      companyName: job.company?.name || "Unknown company",
      jobTitle: job.jobTitle || "Unknown role",
      provider: provider.provider,
      providerName: provider.displayName,
      fromAddress: provider.address || "Connected account",
      to: "",
      subject: "",
      bodyText: "",
      threadId: "",
      clientRequestId: globalThis.crypto.randomUUID(),
    });
    setComposeSetupOpen(false);
    setSendResult(null);
    setSendError(null);
    setDraftError(null);
  };

  const updateDraft = (changes: Partial<Pick<EmailDraft, "to" | "subject" | "bodyText">>) => {
    setDraft((current) => current ? {
      ...current,
      ...changes,
      clientRequestId: sendResult ? globalThis.crypto.randomUUID() : current.clientRequestId,
    } : null);
    if (sendResult) setSendResult(null);
    setSendError(null);
  };

  const discardDraft = async () => {
    if (draft?.bodyText.trim() && !(await confirm({
      title: "Discard email draft?",
      message: "Your unsent draft text will be lost.",
      confirmLabel: "Discard draft",
      destructive: true,
    }))) return;
    if (draft?.id && draft.revision) {
      try {
        await api.delete(`/email/drafts/${draft.id}`, { params: { revision: draft.revision } });
        await loadStoredDrafts();
      } catch (error) {
        setDraftError(getApiErrorMessage(error, "The saved draft changed elsewhere. Reload it before discarding."));
        return;
      }
    }
    setDraft(null);
    setSendResult(null);
    setSendError(null);
    setDraftError(null);
  };

  const saveDraft = async () => {
    if (!draft || savingDraft || sendResult) return;
    setSavingDraft(true);
    setDraftError(null);
    try {
      const response = draft.id && draft.revision
        ? await api.put<StoredEmailDraft>(`/email/drafts/${draft.id}`, {
            revision: draft.revision,
            to: draft.to,
            subject: draft.subject,
            bodyText: draft.bodyText,
          })
        : await api.post<StoredEmailDraft>("/email/drafts", {
            jobApplicationId: draft.jobApplicationId,
            provider: draft.provider,
            to: draft.to,
            subject: draft.subject,
            bodyText: draft.bodyText,
            threadId: draft.threadId || null,
          });
      setDraft((current) => current ? { ...current, ...response.data } : null);
      await loadStoredDrafts();
      toast("Email draft saved.", "success");
    } catch (error: any) {
      setDraftError(error?.response?.status === 409
        ? "This draft changed in another tab. Resume the latest saved version before editing again."
        : getApiErrorMessage(error, "Failed to save the email draft."));
    } finally {
      setSavingDraft(false);
    }
  };

  const sendDraft = async () => {
    if (!draft || sending || !draft.to.trim() || !draft.subject.trim() || !draft.bodyText.trim()) return;
    const approved = await confirm({
      title: "Confirm email send",
      message: `Send with ${draft.providerName} (${draft.fromAddress}) to ${draft.to.trim()}? Subject: ${draft.subject.trim()}. Thread: ${draft.threadId || "New message"}.`,
      confirmLabel: "Send email",
    });
    if (!approved) return;

    setSending(true);
    setSendError(null);
    try {
      const response = await api.post<EmailSendResult>("/email/send", {
        jobApplicationId: draft.jobApplicationId,
        provider: draft.provider,
        clientRequestId: draft.clientRequestId,
        to: draft.to.trim(),
        subject: draft.subject.trim(),
        bodyText: draft.bodyText,
        threadId: draft.threadId || null,
        confirmed: true,
      });
      setSendResult(response.data);
      if (response.data.status === "sent") {
        toast("Email sent and saved to this job.", "success");
        if (draft.id && draft.revision) {
          try {
            await api.delete(`/email/drafts/${draft.id}`, { params: { revision: draft.revision } });
            setDraft((current) => current ? { ...current, id: undefined, revision: undefined } : null);
            await loadStoredDrafts();
          } catch {
            toast("Email was sent, but a newer saved draft still exists. Review it before taking another action.", "warning");
          }
        }
        await load();
      }
    } catch (error: any) {
      const result = error?.response?.data;
      if (["failed", "uncertain", "sent", "pending", "sending"].includes(result?.status)) {
        setSendResult(result as EmailSendResult);
      } else if (!error?.response || error.response.status >= 500) {
        setSendResult({ attemptId: draft.clientRequestId, status: "uncertain", duplicate: false, failureCategory: "client_connection_lost" });
      } else {
        setSendResult({ attemptId: draft.clientRequestId, status: "failed", duplicate: false });
      }
      setSendError(getApiErrorMessage(error, "The email could not be sent."));
    } finally {
      setSending(false);
    }
  };

  const prepareNewAttempt = async () => {
    if (!draft || sendResult?.status !== "failed") return;
    setDraftError(null);
    if (draft.id && draft.revision) {
      try {
        const response = await api.post<StoredEmailDraft>(`/email/drafts/${draft.id}/new-attempt`, { revision: draft.revision });
        setDraft((current) => current ? { ...current, ...response.data } : null);
        await loadStoredDrafts();
      } catch (error: any) {
        setDraftError(error?.response?.status === 409
          ? "A new attempt is allowed only after the latest saved draft has a definitive failed delivery. Reload the draft before continuing."
          : getApiErrorMessage(error, "Failed to prepare a new delivery attempt."));
        return;
      }
    } else {
      setDraft((current) => current ? { ...current, clientRequestId: globalThis.crypto.randomUUID() } : null);
    }
    setSendResult(null);
    setSendError(null);
  };

  const unlinkGmailThread = async (item: CorrespondenceInboxItem) => {
    if (item.provider !== "gmail" || !item.externalThreadId || unlinkingThreadId) return;
    if (!(await confirm({
      title: "Unlink Gmail thread?",
      message: `Remove this Gmail thread from ${item.companyName || "this job"} and return it to recruitment review? The provider copy is not deleted.`,
      confirmLabel: "Unlink thread",
      destructive: true,
    }))) return;

    setUnlinkingThreadId(item.externalThreadId);
    try {
      await api.post("/gmail/unlink-thread", {
        jobApplicationId: item.jobApplicationId,
        threadId: item.externalThreadId,
        note: "Unlinked from Job email hub",
        nextDecision: "review",
      });
      if (selectedMessageId === item.id) {
        detailRequest.current += 1;
        setSelectedMessageId(null);
        setMessageDetail(null);
      }
      await load();
      toast("Gmail thread returned to recruitment review.", "success");
    } catch (error) {
      toast(getApiErrorMessage(error, "Failed to unlink the Gmail thread."), "error");
    } finally {
      setUnlinkingThreadId(null);
    }
  };

  return (
    <Paper
      sx={{
        mt: 0,
        p: 2,
        borderRadius: 4,
        border: "none",
        boxShadow: "0px 1px 2px 0px rgba(15,23,42,0.04), 0px 8px 24px -12px rgba(15,23,42,0.12)",
      }}
    >
      <Box sx={{ display: "flex", justifyContent: "space-between", gap: 2, alignItems: "center", flexWrap: "wrap", mb: 2 }}>
        <Box>
          <Typography component="h1" variant="h5" sx={{ fontWeight: 900 }}>Job email</Typography>
          <Typography variant="body2" sx={{ color: "text.secondary" }}>
            Review linked correspondence and suggested recruitment messages in one place.
          </Typography>
        </Box>
        <Box sx={{ display: "flex", gap: 1, flexWrap: "wrap", alignItems: "center" }}>
          {view === "inbox" ? <Chip icon={<MailOutlineIcon />} label={`${items.length} items`} variant="outlined" /> : null}
          {view === "inbox" ? <Chip label={`${filteredSummary.linked} linked`} variant="outlined" color={filteredSummary.linked > 0 ? "success" : "default"} /> : null}
          {view === "inbox" ? <Chip label={`${filteredSummary.inbound} inbound`} variant="outlined" /> : null}
          <Button variant={view === "inbox" ? "contained" : "text"} size="small" onClick={() => setSearchParams({})}>Linked messages</Button>
          <Button variant={view === "review" ? "contained" : "text"} size="small" onClick={() => setSearchParams({ view: "review" })}>Review suggestions</Button>
          <Button variant="outlined" size="small" onClick={openComposeSetup} disabled={jobs.length === 0 || sendCapableProviders.length === 0}>Compose new email</Button>
        </Box>
      </Box>

      <Box sx={{ display: "flex", gap: 1, flexWrap: "wrap", mb: 2 }} aria-label="Email provider status">
        {providers.map((provider) => (
          <Chip
            key={provider.provider}
            size="small"
            color={provider.connected ? "success" : "default"}
            variant="outlined"
            label={emailProviderStatusLabel(provider)}
          />
        ))}
      </Box>
      {providerStatusError ? (
        <Alert severity="warning" sx={{ mb: 2 }}>Email provider status is temporarily unavailable. Saved JobTracker correspondence remains available.</Alert>
      ) : null}
      {jobsLoaded && jobs.length === 0 ? <Alert severity="info" sx={{ mb: 2 }}>Add a job before composing a new email.</Alert> : null}
      {providerStatusLoaded && !providerStatusError && sendCapableProviders.length === 0 ? <Alert severity="info" sx={{ mb: 2 }}>Reconnect Gmail or Outlook with send access before composing a new email.</Alert> : null}
      {draftError && !draft ? <Alert severity="warning" sx={{ mb: 2 }}>{draftError}</Alert> : null}

      {storedDrafts.length > 0 ? (
        <Alert severity="info" sx={{ mb: 2 }}>
          <Stack direction="row" spacing={1} useFlexGap flexWrap="wrap" alignItems="center">
            <Typography variant="body2">{storedDrafts.length} saved email draft{storedDrafts.length === 1 ? "" : "s"} available.</Typography>
            {storedDrafts.slice(0, 5).map((stored) => (
              <Button key={stored.id} size="small" onClick={() => void resumeDraft(stored)}>
                Resume {stored.subject || `job #${stored.jobApplicationId}`}
              </Button>
            ))}
          </Stack>
        </Alert>
      ) : null}

      {composeSetupOpen ? (
        <Paper component="section" aria-labelledby="compose-new-title" variant="outlined" sx={{ p: 2, borderRadius: 3, mb: 2 }}>
          <Typography id="compose-new-title" component="h2" variant="h6" sx={{ fontWeight: 900, mb: 1.5 }}>Compose new email</Typography>
          <Box sx={{ display: "grid", gridTemplateColumns: { xs: "1fr", md: "1fr 1fr auto" }, gap: 1.25, alignItems: "center" }}>
            <FormControl fullWidth>
              <InputLabel id="compose-job-label">Job</InputLabel>
              <Select labelId="compose-job-label" value={composeJobId} label="Job" onChange={(event) => setComposeJobId(Number(event.target.value))}>
                {jobs.map((job) => <MenuItem key={job.id} value={job.id}>{job.company?.name || "Unknown company"} · {job.jobTitle}</MenuItem>)}
              </Select>
            </FormControl>
            <FormControl fullWidth>
              <InputLabel id="compose-provider-label">Sending provider</InputLabel>
              <Select labelId="compose-provider-label" value={composeProvider} label="Sending provider" onChange={(event) => setComposeProvider(String(event.target.value))}>
                {sendCapableProviders.map((provider) => <MenuItem key={provider.provider} value={provider.provider}>{provider.displayName} · {provider.address || "Connected account"}</MenuItem>)}
              </Select>
            </FormControl>
            <Box sx={{ display: "flex", gap: 1 }}>
              <Button onClick={() => setComposeSetupOpen(false)}>Cancel</Button>
              <Button variant="contained" onClick={() => void startNewMessage()} disabled={!composeJobId || !composeProvider}>Start draft</Button>
            </Box>
          </Box>
        </Paper>
      ) : null}

      {view === "review" ? <GmailReviewPage embedded /> : <>
        <Box sx={{ display: "grid", gridTemplateColumns: { xs: "1fr", md: "2fr 1fr 1fr auto" }, gap: 1.25, mb: 2 }}>
        <TextField label="Search" value={query} onChange={(e) => setQuery(e.target.value)} placeholder="Company, role, recruiter, subject" />
        <FormControl fullWidth>
          <InputLabel>Direction</InputLabel>
          <Select value={direction} label="Direction" onChange={(e) => setDirection(String(e.target.value))}>
            <MenuItem value="all">All</MenuItem>
            <MenuItem value="inbound">Inbound</MenuItem>
            <MenuItem value="outbound">Outbound</MenuItem>
            <MenuItem value="internal">Internal</MenuItem>
          </Select>
        </FormControl>
        <FormControl fullWidth>
          <InputLabel>Link state</InputLabel>
          <Select value={linkState} label="Link state" onChange={(e) => setLinkState(String(e.target.value))}>
            <MenuItem value="all">All</MenuItem>
            <MenuItem value="linked">Linked threads</MenuItem>
            <MenuItem value="manual">Manual/internal only</MenuItem>
          </Select>
        </FormControl>
        <Button variant="contained" onClick={() => void load()} disabled={loading}>{loading ? "Loading..." : "Refresh"}</Button>
        </Box>

      {draft ? (
        <Paper component="section" aria-labelledby="email-draft-title" variant="outlined" sx={{ p: 2, borderRadius: 3, mb: 2 }}>
          <Box sx={{ display: "flex", justifyContent: "space-between", gap: 2, flexWrap: "wrap", mb: 1.5 }}>
            <Box>
              <Typography id="email-draft-title" component="h2" variant="h6" sx={{ fontWeight: 900 }}>Email draft</Typography>
              <Typography variant="body2" sx={{ color: "text.secondary" }}>{draft.companyName} · {draft.jobTitle}</Typography>
            </Box>
            <Button onClick={() => void discardDraft()} disabled={sending}>Discard draft</Button>
          </Box>
          <Box sx={{ display: "grid", gridTemplateColumns: { xs: "1fr", md: "1fr 1fr" }, gap: 1.25 }}>
            <TextField label="Provider" value={`${draft.providerName} · ${draft.fromAddress}`} slotProps={{ input: { readOnly: true } }} />
            <TextField label="Thread" value={draft.threadId || "New message"} slotProps={{ input: { readOnly: true } }} />
            <TextField label="Recipient" type="email" value={draft.to} onChange={(event) => updateDraft({ to: event.target.value })} disabled={sending} inputProps={{ maxLength: 320 }} />
            <TextField label="Subject" value={draft.subject} onChange={(event) => updateDraft({ subject: event.target.value })} disabled={sending} inputProps={{ maxLength: 998 }} />
            <TextField label="Message" value={draft.bodyText} onChange={(event) => updateDraft({ bodyText: event.target.value })} disabled={sending} multiline minRows={6} inputProps={{ maxLength: 200000 }} helperText={`${draft.bodyText.length} / 200000 characters`} sx={{ gridColumn: "1 / -1" }} />
          </Box>
          {sendResult?.status === "sent" ? <Alert severity="success" sx={{ mt: 1.5 }}>Sent successfully. This exact attempt cannot be sent again.</Alert> : null}
          {sendResult?.status === "uncertain" || sendResult?.status === "sending" || sendResult?.status === "pending" ? (
            <Alert severity="warning" sx={{ mt: 1.5 }}>Delivery status is uncertain. Do not retry this draft. Check the provider Sent folder before taking any further action.</Alert>
          ) : null}
          {sendResult?.status === "failed" ? (
            <Alert severity="error" sx={{ mt: 1.5 }} action={<Button color="inherit" size="small" onClick={() => void prepareNewAttempt()}>Prepare new attempt</Button>}>
              The provider confirmed that this attempt did not complete. Review the connection and draft before creating a new attempt.
            </Alert>
          ) : null}
          {draftError ? <Alert severity="warning" sx={{ mt: 1.5 }}>{draftError}</Alert> : null}
          {sendError && sendResult?.status !== "uncertain" ? <Typography variant="body2" sx={{ color: "error.main", mt: 1 }}>{sendError}</Typography> : null}
          <Box sx={{ display: "flex", justifyContent: "flex-end", gap: 1, mt: 1.5, flexWrap: "wrap" }}>
            <Button variant="outlined" onClick={() => void saveDraft()} disabled={savingDraft || sending || !!sendResult}>
              {savingDraft ? "Saving…" : draft.id ? "Save changes" : "Save draft"}
            </Button>
            <Button variant="contained" onClick={() => void sendDraft()} disabled={sending || !!sendResult || !draft.to.trim() || !draft.subject.trim() || !draft.bodyText.trim()}>
              {sending ? "Sending…" : "Review and send"}
            </Button>
          </Box>
        </Paper>
      ) : null}

      {loading ? <Box sx={{ py: 6, display: "flex", justifyContent: "center" }}><CircularProgress size={28} /></Box> : null}

      {!loading && items.length === 0 ? (
        <Typography sx={{ color: "text.secondary", py: 4, textAlign: "center" }}>No correspondence matches the current filters.</Typography>
      ) : null}

      <Stack spacing={1.25}>
        {items.map((item) => (
          <Paper key={item.id} variant="outlined" sx={{ p: 1.5, borderRadius: 3 }}>
            <Box sx={{ display: "flex", justifyContent: "space-between", gap: 2, flexWrap: "wrap", alignItems: "flex-start" }}>
              <Box sx={{ minWidth: 0 }}>
                <Typography sx={{ fontWeight: 800, overflowWrap: "anywhere" }}>{item.companyName || "Unknown company"} • {item.jobTitle || "Unknown role"}</Typography>
                <Typography variant="body2" sx={{ color: "text.secondary", overflowWrap: "anywhere" }}>{item.subject || item.contentPreview}</Typography>
                <Typography variant="caption" sx={{ color: "text.secondary", display: "block", mt: 0.5 }}>
                  {item.externalFrom || item.from} {item.externalTo ? `→ ${item.externalTo}` : ""} · {new Date(item.date).toLocaleString()}
                </Typography>
              </Box>
              <Box sx={{ display: "flex", gap: 0.75, flexWrap: "wrap", justifyContent: "flex-end" }}>
                {item.direction ? <Chip size="small" label={item.direction} variant="outlined" /> : null}
                {item.provider ? <Chip size="small" label={item.provider === "microsoft" ? "Outlook" : item.provider === "gmail" ? "Gmail" : item.provider.toUpperCase()} variant="outlined" /> : null}
                {item.externalThreadId ? <Chip size="small" label={`Thread ${item.externalThreadId}`} color="success" variant="outlined" /> : <Chip size="small" label="Manual/internal" variant="outlined" />}
                {item.labelCount > 0 ? <Chip size="small" label={`${item.labelCount} labels`} variant="outlined" /> : null}
                {item.attachmentCount > 0 ? <Chip size="small" label={`${item.attachmentCount} attachments`} variant="outlined" /> : null}
                <Button size="small" variant="text" onClick={() => void showMessage(item)}>{selectedMessageId === item.id ? "Hide message" : "View message"}</Button>
                <Button size="small" variant="text" onClick={() => navigate(`/jobs/${item.jobApplicationId}?section=communication`)}>Open job</Button>
                {item.provider === "gmail" && item.externalThreadId ? (
                  <Button size="small" color="warning" variant="text" disabled={unlinkingThreadId === item.externalThreadId} onClick={() => void unlinkGmailThread(item)}>
                    {unlinkingThreadId === item.externalThreadId ? "Unlinking…" : "Unlink thread"}
                  </Button>
                ) : null}
              </Box>
            </Box>
            {selectedMessageId === item.id ? (
              <Box sx={{ mt: 1.5, pt: 1.5, borderTop: "1px solid", borderColor: "divider" }}>
                {detailLoading ? <Box sx={{ display: "flex", gap: 1, alignItems: "center" }}><CircularProgress size={18} /><Typography variant="body2">Loading message…</Typography></Box> : null}
                {detailNotice ? <Alert severity="warning" sx={{ mb: 1 }}>{detailNotice}</Alert> : null}
                {detailError ? <Alert severity="error">{detailError}</Alert> : null}
                {messageDetail ? <>
                  <Typography sx={{ fontWeight: 800 }}>{messageDetail.subject || "No subject"}</Typography>
                  <Typography variant="caption" sx={{ color: "text.secondary", display: "block", mb: 1 }}>{messageDetail.from}{messageDetail.to ? ` → ${messageDetail.to}` : ""}</Typography>
                  <Typography sx={{ whiteSpace: "pre-wrap", overflowWrap: "anywhere" }}>{messageDetail.bodyText}</Typography>
                  {(messageDetail.labels.length > 0 || messageDetail.attachments.length > 0) ? <Box sx={{ display: "flex", gap: 0.75, flexWrap: "wrap", mt: 1 }}>
                    {messageDetail.labels.map((label, index) => <Chip key={`${label}-${index}`} size="small" label={label} variant="outlined" />)}
                    {messageDetail.attachments.map((attachment, index) => <Chip key={`${attachment.fileName || "attachment"}-${index}`} size="small" label={attachment.fileName || "Attachment"} variant="outlined" />)}
                  </Box> : null}
                  {item.provider && providers.find((provider) => provider.provider === item.provider)?.canSend ? (
                    <Button sx={{ mt: 1.5 }} variant="outlined" onClick={() => void startReply(item)}>Reply with connected provider</Button>
                  ) : item.provider && item.provider !== "manual" ? (
                    <Alert severity="info" sx={{ mt: 1.5 }}>Reconnect this provider with send access to reply from JobTracker.</Alert>
                  ) : null}
                </> : null}
              </Box>
            ) : null}
          </Paper>
        ))}
      </Stack>
      </>}
    </Paper>
  );
}