import type {
  Approval,
  DashboardSummary,
  HeartbeatRun,
  InboxDismissal,
  Issue,
  JoinRequest,
} from "@paperclipai/shared";

export const RECENT_ISSUES_LIMIT = 100;
export const FAILED_RUN_STATUSES = new Set(["failed", "timed_out"]);
export const ACTIONABLE_APPROVAL_STATUSES = new Set(["pending", "revision_requested"]);
export const DISMISSED_KEY = "paperclip:inbox:dismissed";
export const READ_ITEMS_KEY = "paperclip:inbox:read-items";
export const INBOX_LAST_TAB_KEY = "paperclip:inbox:last-tab";
export const INBOX_ISSUE_COLUMNS_KEY = "paperclip:inbox:issue-columns";
export const INBOX_NESTING_KEY = "paperclip:inbox:nesting";
export type InboxTab = "mine" | "recent" | "unread" | "all";
export type InboxApprovalFilter = "all" | "actionable" | "resolved";
export const inboxIssueColumns = ["status", "id", "assignee", "project", "workspace", "parent", "labels", "updated"] as const;
export type InboxIssueColumn = (typeof inboxIssueColumns)[number];
export const DEFAULT_INBOX_ISSUE_COLUMNS: InboxIssueColumn[] = ["status", "id", "updated"];
export type InboxWorkItem =
  | {
      kind: "issue";
      timestamp: number;
      issue: Issue;
    }
  | {
      kind: "approval";
      timestamp: number;
      approval: Approval;
    }
  | {
      kind: "failed_run";
      timestamp: number;
      run: HeartbeatRun;
    }
  | {
      kind: "join_request";
      timestamp: number;
      joinRequest: JoinRequest;
    };

export interface InboxBadgeData {
  inbox: number;
  approvals: number;
  failedRuns: number;
  joinRequests: number;
  mineIssues: number;
  alerts: number;
}

export function loadDismissedInboxAlerts(): Set<string> {
  try {
    const raw = localStorage.getItem(DISMISSED_KEY);
    if (!raw) return new Set();
    const parsed = JSON.parse(raw);
    if (!Array.isArray(parsed)) return new Set();
    return new Set(parsed.filter((value): value is string => typeof value === "string" && value.startsWith("alert:")));
  } catch {
    return new Set();
  }
}

export function saveDismissedInboxAlerts(ids: Set<string>) {
  try {
    localStorage.setItem(DISMISSED_KEY, JSON.stringify([...ids]));
  } catch {
    // Ignore localStorage failures.
  }
}

export function buildInboxDismissedAtByKey(dismissals: InboxDismissal[]): Map<string, number> {
  return new Map(
    dismissals.map((dismissal) => [dismissal.itemKey, normalizeTimestamp(dismissal.dismissedAt)]),
  );
}

export function isInboxEntityDismissed(
  dismissedAtByKey: ReadonlyMap<string, number>,
  itemKey: string,
  activityAt: string | Date | null | undefined,
): boolean {
  const dismissedAt = dismissedAtByKey.get(itemKey);
  if (dismissedAt == null) return false;
  return dismissedAt >= normalizeTimestamp(activityAt);
}

export function loadReadInboxItems(): Set<string> {
  try {
    const raw = localStorage.getItem(READ_ITEMS_KEY);
    return raw ? new Set(JSON.parse(raw)) : new Set();
  } catch {
    return new Set();
  }
}

export function saveReadInboxItems(ids: Set<string>) {
  try {
    localStorage.setItem(READ_ITEMS_KEY, JSON.stringify([...ids]));
  } catch {
    // Ignore localStorage failures.
  }
}

export function normalizeInboxIssueColumns(columns: Iterable<string | InboxIssueColumn>): InboxIssueColumn[] {
  const selected = new Set(columns);
  return inboxIssueColumns.filter((column) => selected.has(column));
}

export function getAvailableInboxIssueColumns(enableWorkspaceColumn: boolean): InboxIssueColumn[] {
  if (enableWorkspaceColumn) return [...inboxIssueColumns];
  return inboxIssueColumns.filter((column) => column !== "workspace");
}

export function loadInboxIssueColumns(): InboxIssueColumn[] {
  try {
    const raw = localStorage.getItem(INBOX_ISSUE_COLUMNS_KEY);
    if (raw === null) return DEFAULT_INBOX_ISSUE_COLUMNS;
    const parsed = JSON.parse(raw);
    if (!Array.isArray(parsed)) return DEFAULT_INBOX_ISSUE_COLUMNS;
    return normalizeInboxIssueColumns(parsed);
  } catch {
    return DEFAULT_INBOX_ISSUE_COLUMNS;
  }
}

export function saveInboxIssueColumns(columns: InboxIssueColumn[]) {
  try {
    localStorage.setItem(
      INBOX_ISSUE_COLUMNS_KEY,
      JSON.stringify(normalizeInboxIssueColumns(columns)),
    );
  } catch {
    // Ignore localStorage failures.
  }
}

export function resolveIssueWorkspaceName(
  issue: Pick<Issue, "executionWorkspaceId" | "projectId" | "projectWorkspaceId">,
  {
    executionWorkspaceById,
    projectWorkspaceById,
    defaultProjectWorkspaceIdByProjectId,
  }: {
    executionWorkspaceById?: ReadonlyMap<string, {
      name: string;
      mode: "shared_workspace" | "isolated_workspace" | "operator_branch" | "adapter_managed" | "cloud_sandbox";
      projectWorkspaceId: string | null;
    }>;
    projectWorkspaceById?: ReadonlyMap<string, { name: string }>;
    defaultProjectWorkspaceIdByProjectId?: ReadonlyMap<string, string>;
  },
): string | null {
  const defaultProjectWorkspaceId = issue.projectId
    ? defaultProjectWorkspaceIdByProjectId?.get(issue.projectId) ?? null
    : null;

  if (issue.executionWorkspaceId) {
    const executionWorkspace = executionWorkspaceById?.get(issue.executionWorkspaceId) ?? null;
    const linkedProjectWorkspaceId =
      executionWorkspace?.projectWorkspaceId ?? issue.projectWorkspaceId ?? null;
    const isDefaultSharedExecutionWorkspace =
      executionWorkspace?.mode === "shared_workspace" && linkedProjectWorkspaceId === defaultProjectWorkspaceId;
    if (isDefaultSharedExecutionWorkspace) return null;

    const workspaceName = executionWorkspace?.name;
    if (workspaceName) return workspaceName;
  }

  if (issue.projectWorkspaceId) {
    if (issue.projectWorkspaceId === defaultProjectWorkspaceId) return null;
    const workspaceName = projectWorkspaceById?.get(issue.projectWorkspaceId)?.name;
    if (workspaceName) return workspaceName;
  }

  return null;
}

export function loadInboxNesting(): boolean {
  try {
    const raw = localStorage.getItem(INBOX_NESTING_KEY);
    return raw !== "false";
  } catch {
    return true;
  }
}

export function saveInboxNesting(enabled: boolean) {
  try {
    localStorage.setItem(INBOX_NESTING_KEY, String(enabled));
  } catch {
    // Ignore localStorage failures.
  }
}

export function resolveInboxNestingEnabled(preferenceEnabled: boolean, isMobile: boolean): boolean {
  return preferenceEnabled && !isMobile;
}

export function loadLastInboxTab(): InboxTab {
  try {
    const raw = localStorage.getItem(INBOX_LAST_TAB_KEY);
    if (raw === "all" || raw === "unread" || raw === "recent" || raw === "mine") return raw;
    if (raw === "new") return "mine";
    return "mine";
  } catch {
    return "mine";
  }
}

export function saveLastInboxTab(tab: InboxTab) {
  try {
    localStorage.setItem(INBOX_LAST_TAB_KEY, tab);
  } catch {
    // Ignore localStorage failures.
  }
}

export function isMineInboxTab(tab: InboxTab): boolean {
  return tab === "mine";
}

export function resolveInboxSelectionIndex(
  previousIndex: number,
  itemCount: number,
): number {
  if (itemCount === 0) return -1;
  if (previousIndex < 0) return -1;
  return Math.min(previousIndex, itemCount - 1);
}

export function getInboxKeyboardSelectionIndex(
  previousIndex: number,
  itemCount: number,
  direction: "next" | "previous",
): number {
  if (itemCount === 0) return -1;
  if (previousIndex < 0) return 0;
  return direction === "next"
    ? Math.min(previousIndex + 1, itemCount - 1)
    : Math.max(previousIndex - 1, 0);
}

export function getLatestFailedRunsByAgent(runs: HeartbeatRun[]): HeartbeatRun[] {
  const sorted = [...runs].sort(
    (a, b) => new Date(b.createdAt).getTime() - new Date(a.createdAt).getTime(),
  );
  const latestByAgent = new Map<string, HeartbeatRun>();

  for (const run of sorted) {
    if (!latestByAgent.has(run.agentId)) {
      latestByAgent.set(run.agentId, run);
    }
  }

  return Array.from(latestByAgent.values()).filter((run) => FAILED_RUN_STATUSES.has(run.status));
}

export function normalizeTimestamp(value: string | Date | null | undefined): number {
  if (!value) return 0;
  const timestamp = new Date(value).getTime();
  return Number.isFinite(timestamp) ? timestamp : 0;
}

export function issueLastActivityTimestamp(issue: Issue): number {
  const lastActivityAt = normalizeTimestamp(issue.lastActivityAt);
  if (lastActivityAt > 0) return lastActivityAt;

  const lastExternalCommentAt = normalizeTimestamp(issue.lastExternalCommentAt);
  if (lastExternalCommentAt > 0) return lastExternalCommentAt;

  return normalizeTimestamp(issue.updatedAt);
}

export function sortIssuesByMostRecentActivity(a: Issue, b: Issue): number {
  const activityDiff = issueLastActivityTimestamp(b) - issueLastActivityTimestamp(a);
  if (activityDiff !== 0) return activityDiff;
  return normalizeTimestamp(b.updatedAt) - normalizeTimestamp(a.updatedAt);
}

export function getRecentTouchedIssues(issues: Issue[]): Issue[] {
  return [...issues].sort(sortIssuesByMostRecentActivity).slice(0, RECENT_ISSUES_LIMIT);
}

export function getUnreadTouchedIssues(issues: Issue[]): Issue[] {
  return issues.filter((issue) => issue.isUnreadForMe);
}

export function getApprovalsForTab(
  approvals: Approval[],
  tab: InboxTab,
  filter: InboxApprovalFilter,
): Approval[] {
  const sortedApprovals = [...approvals].sort(
    (a, b) => normalizeTimestamp(b.updatedAt) - normalizeTimestamp(a.updatedAt),
  );

  if (tab === "mine" || tab === "recent") return sortedApprovals;
  if (tab === "unread") {
    return sortedApprovals.filter((approval) => ACTIONABLE_APPROVAL_STATUSES.has(approval.status));
  }
  if (filter === "all") return sortedApprovals;

  return sortedApprovals.filter((approval) => {
    const isActionable = ACTIONABLE_APPROVAL_STATUSES.has(approval.status);
    return filter === "actionable" ? isActionable : !isActionable;
  });
}

export function approvalActivityTimestamp(approval: Approval): number {
  const updatedAt = normalizeTimestamp(approval.updatedAt);
  if (updatedAt > 0) return updatedAt;
  return normalizeTimestamp(approval.createdAt);
}

export function getInboxWorkItems({
  issues,
  approvals,
  failedRuns = [],
  joinRequests = [],
}: {
  issues: Issue[];
  approvals: Approval[];
  failedRuns?: HeartbeatRun[];
  joinRequests?: JoinRequest[];
}): InboxWorkItem[] {
  return [
    ...issues.map((issue) => ({
      kind: "issue" as const,
      timestamp: issueLastActivityTimestamp(issue),
      issue,
    })),
    ...approvals.map((approval) => ({
      kind: "approval" as const,
      timestamp: approvalActivityTimestamp(approval),
      approval,
    })),
    ...failedRuns.map((run) => ({
      kind: "failed_run" as const,
      timestamp: normalizeTimestamp(run.createdAt),
      run,
    })),
    ...joinRequests.map((joinRequest) => ({
      kind: "join_request" as const,
      timestamp: normalizeTimestamp(joinRequest.createdAt),
      joinRequest,
    })),
  ].sort((a, b) => {
    const timestampDiff = b.timestamp - a.timestamp;
    if (timestampDiff !== 0) return timestampDiff;

    if (a.kind === "issue" && b.kind === "issue") {
      return sortIssuesByMostRecentActivity(a.issue, b.issue);
    }
    if (a.kind === "approval" && b.kind === "approval") {
      return approvalActivityTimestamp(b.approval) - approvalActivityTimestamp(a.approval);
    }

    return a.kind === "approval" ? -1 : 1;
  });
}

/**
 * Groups parent-child issues in a flat InboxWorkItem list.
 *
 * - Children whose parent is also in the list are removed from the top level
 *   and stored in `childrenByIssueId`.
 * - The parent's sort timestamp becomes max(parent, children) so that a group
 *   with a recently-updated child floats to the top.
 * - If a parent is absent (e.g. archived), children remain as independent roots.
 */
export function buildInboxNesting(items: InboxWorkItem[]): {
  displayItems: InboxWorkItem[];
  childrenByIssueId: Map<string, Issue[]>;
} {
  const issueItems: (InboxWorkItem & { kind: "issue" })[] = [];
  const nonIssueItems: InboxWorkItem[] = [];
  for (const item of items) {
    if (item.kind === "issue") issueItems.push(item as InboxWorkItem & { kind: "issue" });
    else nonIssueItems.push(item);
  }

  const issueIdSet = new Set(issueItems.map((i) => i.issue.id));
  const childrenByIssueId = new Map<string, Issue[]>();
  const childIds = new Set<string>();

  for (const item of issueItems) {
    const { issue } = item;
    if (issue.parentId && issueIdSet.has(issue.parentId)) {
      childIds.add(issue.id);
      const arr = childrenByIssueId.get(issue.parentId) ?? [];
      arr.push(issue);
      childrenByIssueId.set(issue.parentId, arr);
    }
  }

  // Sort each child list by most recent activity
  for (const children of childrenByIssueId.values()) {
    children.sort(sortIssuesByMostRecentActivity);
  }

  // Build root issue items with group-adjusted timestamps
  const rootIssueItems: InboxWorkItem[] = issueItems
    .filter((item) => !childIds.has(item.issue.id))
    .map((item) => {
      const children = childrenByIssueId.get(item.issue.id);
      if (!children?.length) return item;
      const maxChildTs = Math.max(...children.map(issueLastActivityTimestamp));
      return { ...item, timestamp: Math.max(item.timestamp, maxChildTs) };
    });

  // Merge and re-sort
  const displayItems = [...rootIssueItems, ...nonIssueItems].sort((a, b) => {
    const diff = b.timestamp - a.timestamp;
    if (diff !== 0) return diff;
    if (a.kind === "issue" && b.kind === "issue") {
      return sortIssuesByMostRecentActivity(a.issue, b.issue);
    }
    return 0;
  });

  return { displayItems, childrenByIssueId };
}

export function shouldShowInboxSection({
  tab,
  hasItems,
  showOnMine,
  showOnRecent,
  showOnUnread,
  showOnAll,
}: {
  tab: InboxTab;
  hasItems: boolean;
  showOnMine: boolean;
  showOnRecent: boolean;
  showOnUnread: boolean;
  showOnAll: boolean;
}): boolean {
  if (!hasItems) return false;
  if (tab === "mine") return showOnMine;
  if (tab === "recent") return showOnRecent;
  if (tab === "unread") return showOnUnread;
  return showOnAll;
}

export function computeInboxBadgeData({
  approvals,
  joinRequests,
  dashboard,
  heartbeatRuns,
  mineIssues,
  dismissedAlerts,
  dismissedAtByKey,
}: {
  approvals: Approval[];
  joinRequests: JoinRequest[];
  dashboard: DashboardSummary | undefined;
  heartbeatRuns: HeartbeatRun[];
  mineIssues: Issue[];
  dismissedAlerts: Set<string>;
  dismissedAtByKey: ReadonlyMap<string, number>;
}): InboxBadgeData {
  const actionableApprovals = approvals.filter(
    (approval) =>
      ACTIONABLE_APPROVAL_STATUSES.has(approval.status) &&
      !isInboxEntityDismissed(dismissedAtByKey, `approval:${approval.id}`, approval.updatedAt),
  ).length;
  const failedRuns = getLatestFailedRunsByAgent(heartbeatRuns).filter(
    (run) => !isInboxEntityDismissed(dismissedAtByKey, `run:${run.id}`, run.createdAt),
  ).length;
  const visibleJoinRequests = joinRequests.filter(
    (jr) => !isInboxEntityDismissed(dismissedAtByKey, `join:${jr.id}`, jr.updatedAt ?? jr.createdAt),
  ).length;
  const visibleMineIssues = mineIssues.filter((issue) => issue.isUnreadForMe).length;
  const agentErrorCount = dashboard?.agents.error ?? 0;
  const monthBudgetCents = dashboard?.costs.monthBudgetCents ?? 0;
  const monthUtilizationPercent = dashboard?.costs.monthUtilizationPercent ?? 0;
  const showAggregateAgentError =
    agentErrorCount > 0 &&
    failedRuns === 0 &&
    !dismissedAlerts.has("alert:agent-errors");
  const showBudgetAlert =
    monthBudgetCents > 0 &&
    monthUtilizationPercent >= 80 &&
    !dismissedAlerts.has("alert:budget");
  const alerts = Number(showAggregateAgentError) + Number(showBudgetAlert);

  return {
    inbox: actionableApprovals + visibleJoinRequests + failedRuns + visibleMineIssues + alerts,
    approvals: actionableApprovals,
    failedRuns,
    joinRequests: visibleJoinRequests,
    mineIssues: visibleMineIssues,
    alerts,
  };
}