import { describe, it, expect } from "vitest";
import type { TaskSwitcherItem } from "@/components/task/task-switcher";
import { applyFilters, applyGroup, applySort, applyView, mergeGroupOrder } from "./apply-view";
import type { FilterClause, SidebarView } from "@/lib/state/slices/ui/sidebar-view-types";
import { DEFAULT_VIEW } from "@/lib/state/slices/ui/sidebar-view-builtins";
import type { Repository } from "@/lib/types/http";
import { repositorySlug } from "@/lib/repository-slug";

function task(overrides: Partial<TaskSwitcherItem>): TaskSwitcherItem {
  return {
    id: overrides.id ?? "t",
    title: overrides.title ?? "Task",
    ...overrides,
  };
}

const C = (c: Omit<FilterClause, "id">): FilterClause => ({ id: "c1", ...c });

describe("applyFilters — basics", () => {
  it("returns all when no clauses", () => {
    const tasks = [task({ id: "a" }), task({ id: "b" })];
    expect(applyFilters(tasks, [])).toHaveLength(2);
  });
});

describe("applyFilters — hasPR", () => {
  it("filters by hasPR is true (task with linked PR)", () => {
    const tasks = [task({ id: "a", prInfo: { number: 1, state: "Open" } }), task({ id: "b" })];
    const out = applyFilters(tasks, [C({ dimension: "hasPR", op: "is", value: true })]);
    expect(out.map((t) => t.id)).toEqual(["a"]);
  });

  it("filters by hasPR is false (task without linked PR)", () => {
    const tasks = [task({ id: "a", prInfo: { number: 1, state: "Open" } }), task({ id: "b" })];
    const out = applyFilters(tasks, [C({ dimension: "hasPR", op: "is", value: false })]);
    expect(out.map((t) => t.id)).toEqual(["b"]);
  });

  it("supports is_not negation on hasPR", () => {
    const tasks = [task({ id: "a", prInfo: { number: 1, state: "Open" } }), task({ id: "b" })];
    const out = applyFilters(tasks, [C({ dimension: "hasPR", op: "is_not", value: true })]);
    expect(out.map((t) => t.id)).toEqual(["b"]);
  });
});

describe("applyFilters — per-dimension", () => {
  it("filters by isPRReview is true (watcher-created task)", () => {
    const tasks = [task({ id: "a", isPRReview: true }), task({ id: "b" })];
    const out = applyFilters(tasks, [C({ dimension: "isPRReview", op: "is", value: true })]);
    expect(out.map((t) => t.id)).toEqual(["a"]);
  });

  it("filters by isPRReview is false (regular task, even with linked PR)", () => {
    const tasks = [
      task({ id: "a", isPRReview: true }),
      task({ id: "b", prInfo: { number: 1, state: "Open" } }),
    ];
    const out = applyFilters(tasks, [C({ dimension: "isPRReview", op: "is", value: false })]);
    expect(out.map((t) => t.id)).toEqual(["b"]);
  });

  it("supports is_not negation on isPRReview", () => {
    const tasks = [task({ id: "a", isPRReview: true }), task({ id: "b" })];
    const out = applyFilters(tasks, [C({ dimension: "isPRReview", op: "is_not", value: true })]);
    expect(out.map((t) => t.id)).toEqual(["b"]);
  });

  it("filters by isIssueWatch is true (issue-watcher-created task)", () => {
    const tasks = [task({ id: "a", isIssueWatch: true }), task({ id: "b" })];
    const out = applyFilters(tasks, [C({ dimension: "isIssueWatch", op: "is", value: true })]);
    expect(out.map((t) => t.id)).toEqual(["a"]);
  });

  it("filters by isIssueWatch is false (regular task)", () => {
    const tasks = [task({ id: "a", isIssueWatch: true }), task({ id: "b" })];
    const out = applyFilters(tasks, [C({ dimension: "isIssueWatch", op: "is", value: false })]);
    expect(out.map((t) => t.id)).toEqual(["b"]);
  });

  it("supports is_not negation on isIssueWatch", () => {
    const tasks = [task({ id: "a", isIssueWatch: true }), task({ id: "b" })];
    const out = applyFilters(tasks, [C({ dimension: "isIssueWatch", op: "is_not", value: true })]);
    expect(out.map((t) => t.id)).toEqual(["b"]);
  });

  it("filters by archived boolean", () => {
    const tasks = [task({ id: "a", isArchived: true }), task({ id: "b" })];
    const only = applyFilters(tasks, [C({ dimension: "archived", op: "is", value: true })]);
    expect(only.map((t) => t.id)).toEqual(["a"]);
    const not = applyFilters(tasks, [C({ dimension: "archived", op: "is", value: false })]);
    expect(not.map((t) => t.id)).toEqual(["b"]);
  });

  it("filters by state bucket with in / not_in", () => {
    const tasks = [
      task({ id: "a", state: "REVIEW" }),
      task({ id: "b", sessionState: "RUNNING" }),
      task({ id: "c" }),
    ];
    const review = applyFilters(tasks, [C({ dimension: "state", op: "in", value: ["review"] })]);
    expect(review.map((t) => t.id)).toEqual(["a"]);
    const notBacklog = applyFilters(tasks, [
      C({ dimension: "state", op: "not_in", value: ["backlog"] }),
    ]);
    expect(notBacklog.map((t) => t.id).sort()).toEqual(["a", "b"]);
  });

  it("filters by repository", () => {
    const tasks = [
      task({ id: "a", repositoryPath: "org/repo1" }),
      task({ id: "b", repositoryPath: "org/repo2" }),
    ];
    const out = applyFilters(tasks, [C({ dimension: "repository", op: "is", value: "org/repo1" })]);
    expect(out.map((t) => t.id)).toEqual(["a"]);
  });

  it("filters by executorType", () => {
    const tasks = [
      task({ id: "a", remoteExecutorType: "sprites" }),
      task({ id: "b", remoteExecutorType: "local_docker" }),
    ];
    const out = applyFilters(tasks, [C({ dimension: "executorType", op: "is", value: "sprites" })]);
    expect(out.map((t) => t.id)).toEqual(["a"]);
  });

  it("filters by workflow + workflowStep", () => {
    const tasks = [
      task({ id: "a", workflowId: "wf1", workflowStepId: "s1" }),
      task({ id: "b", workflowId: "wf2", workflowStepId: "s1" }),
      task({ id: "c", workflowId: "wf1", workflowStepId: "s2" }),
    ];
    const out = applyFilters(tasks, [
      { id: "c1", dimension: "workflow", op: "is", value: "wf1" },
      { id: "c2", dimension: "workflowStep", op: "is", value: "s1" },
    ]);
    expect(out.map((t) => t.id)).toEqual(["a"]);
  });

  it("filters by hasDiff", () => {
    const tasks = [
      task({ id: "a", diffStats: { additions: 10, deletions: 0 } }),
      task({ id: "b", diffStats: { additions: 0, deletions: 0 } }),
      task({ id: "c" }),
    ];
    const withDiff = applyFilters(tasks, [C({ dimension: "hasDiff", op: "is", value: true })]);
    expect(withDiff.map((t) => t.id)).toEqual(["a"]);
    const noDiff = applyFilters(tasks, [C({ dimension: "hasDiff", op: "is", value: false })]);
    expect(noDiff.map((t) => t.id).sort()).toEqual(["b", "c"]);
  });
});

describe("applyFilters — repository (#1213)", () => {
  // The saved clause value is the filter option value, and the board sets each
  // task's repositoryPath — BOTH via repositorySlug. For a local repo the slug
  // is the repo name (not the full local_path). The bug was that the option
  // value used local_path while the board used the name, so the clause matched
  // nothing and the board went empty.
  it("filters by a local repository (option value matches the board task field)", () => {
    const localRepo = {
      id: "r1",
      workspace_id: "w1",
      name: "kandev",
      source_type: "local",
      local_path: "/home/carlos/Projects/kandev",
      provider: "",
      provider_repo_id: "",
      provider_owner: "",
      provider_name: "",
      default_branch: "main",
    } as Repository;
    const optionValue = repositorySlug(localRepo);
    // The option value is the repo name, never the full filesystem path.
    expect(optionValue).toBe("kandev");
    expect(optionValue).not.toBe(localRepo.local_path);
    const tasks = [
      task({ id: "a", repositoryPath: repositorySlug(localRepo) }),
      task({ id: "b", repositoryPath: "org/other" }),
    ];
    const out = applyFilters(tasks, [C({ dimension: "repository", op: "is", value: optionValue })]);
    expect(out.map((t) => t.id)).toEqual(["a"]);
  });
});

describe("applyFilters — titleMatch + combos", () => {
  it("filters by titleMatch matches (case-insensitive substring)", () => {
    const tasks = [
      task({ id: "a", title: "Fix auth bug" }),
      task({ id: "b", title: "Update deps" }),
      task({ id: "c", title: "AUTHenticate users" }),
    ];
    const out = applyFilters(tasks, [C({ dimension: "titleMatch", op: "matches", value: "auth" })]);
    expect(out.map((t) => t.id).sort()).toEqual(["a", "c"]);
  });

  it("filters by titleMatch not_matches", () => {
    const tasks = [
      task({ id: "a", title: "Fix auth bug" }),
      task({ id: "b", title: "Update deps" }),
    ];
    const out = applyFilters(tasks, [
      C({ dimension: "titleMatch", op: "not_matches", value: "auth" }),
    ]);
    expect(out.map((t) => t.id)).toEqual(["b"]);
  });

  it("AND combines multiple clauses", () => {
    const tasks = [
      task({ id: "a", sessionState: "RUNNING", isPRReview: true }),
      task({ id: "b", sessionState: "RUNNING" }),
      task({ id: "c", isPRReview: true }),
    ];
    const out = applyFilters(tasks, [
      C({ dimension: "state", op: "is", value: "in_progress" }),
      { id: "c2", dimension: "isPRReview", op: "is", value: true },
    ]);
    expect(out.map((t) => t.id)).toEqual(["a"]);
  });
});

describe("applySort", () => {
  const a = task({ id: "a", state: "REVIEW", updatedAt: "2026-04-01", title: "Zeta" });
  const b = task({ id: "b", sessionState: "RUNNING", updatedAt: "2026-04-05", title: "Alpha" });
  const c = task({ id: "c", updatedAt: "2026-04-03", title: "Mu" });

  it("sorts by state bucket asc (review, in_progress, backlog)", () => {
    const out = applySort([c, b, a], { key: "state", direction: "asc" });
    expect(out.map((t) => t.id)).toEqual(["a", "b", "c"]);
  });

  it("sorts by state bucket desc", () => {
    const out = applySort([a, b, c], { key: "state", direction: "desc" });
    expect(out.map((t) => t.id)).toEqual(["c", "b", "a"]);
  });

  it("sorts by updatedAt desc", () => {
    const out = applySort([a, b, c], { key: "updatedAt", direction: "desc" });
    expect(out.map((t) => t.id)).toEqual(["b", "c", "a"]);
  });

  it("sorts by title asc", () => {
    const out = applySort([a, b, c], { key: "title", direction: "asc" });
    expect(out.map((t) => t.id)).toEqual(["b", "c", "a"]);
  });

  it("is stable for equal keys", () => {
    const x = task({ id: "x", state: "REVIEW" });
    const y = task({ id: "y", state: "REVIEW" });
    const z = task({ id: "z", state: "REVIEW" });
    const out = applySort([x, y, z], { key: "state", direction: "asc" });
    expect(out.map((t) => t.id)).toEqual(["x", "y", "z"]);
  });
});

describe("applyGroup — state", () => {
  it("groups by real task state instead of the action bucket", () => {
    const tasks = [
      task({ id: "done", state: "COMPLETED", sessionState: "COMPLETED" }),
      task({ id: "review", state: "REVIEW", sessionState: "WAITING_FOR_INPUT" }),
      task({ id: "not-started", sessionState: "IDLE" }),
    ];
    const groupsByKey = new Map(applyGroup(tasks, "state").groups.map((g) => [g.key, g]));

    expect(groupsByKey.get("COMPLETED")?.label).toBe("Completed");
    expect(groupsByKey.get("COMPLETED")?.tasks.map((t) => t.id)).toEqual(["done"]);
    expect(groupsByKey.get("REVIEW")?.label).toBe("Review");
    expect(groupsByKey.get("REVIEW")?.tasks.map((t) => t.id)).toEqual(["review"]);
    expect(groupsByKey.get("__not_started__")?.label).toBe("Not started");
    expect(groupsByKey.get("__not_started__")?.tasks.map((t) => t.id)).toEqual(["not-started"]);
  });

  it("sorts state groups by canonical status order", () => {
    const tasks = [
      task({ id: "cancelled", state: "CANCELLED" }),
      task({ id: "completed", state: "COMPLETED" }),
      task({ id: "failed", state: "FAILED" }),
      task({ id: "blocked", state: "BLOCKED" }),
      task({ id: "review", state: "REVIEW" }),
      task({ id: "waiting", state: "WAITING_FOR_INPUT" }),
      task({ id: "progress", state: "IN_PROGRESS" }),
      task({ id: "todo", state: "TODO" }),
      task({ id: "scheduling", state: "SCHEDULING" }),
      task({ id: "created", state: "CREATED" }),
      task({ id: "not-started" }),
    ];

    expect(applyGroup(tasks, "state").groups.map((g) => g.key)).toEqual([
      "__not_started__",
      "CREATED",
      "SCHEDULING",
      "TODO",
      "IN_PROGRESS",
      "WAITING_FOR_INPUT",
      "REVIEW",
      "BLOCKED",
      "FAILED",
      "COMPLETED",
      "CANCELLED",
    ]);
  });
});

describe("applyGroup", () => {
  it("wraps all tasks in single pseudo-group when group=none", () => {
    const tasks = [task({ id: "a" }), task({ id: "b" })];
    const out = applyGroup(tasks, "none");
    expect(out.groups).toHaveLength(1);
    expect(out.groups[0].tasks).toHaveLength(2);
  });

  it("groups by repository with multi-repo + per-repo buckets", () => {
    const tasks = [
      task({ id: "a", repositories: ["org/r1", "org/r2"] }),
      task({ id: "b", repositoryPath: "org/r1" }),
      task({ id: "c", repositoryPath: "org/r2" }),
      task({ id: "d" }),
    ];
    const out = applyGroup(tasks, "repository");
    const labels = out.groups.map((g) => g.label);
    expect(labels).toContain("Multi-repo");
    expect(labels).toContain("org/r1");
    expect(labels).toContain("org/r2");
    expect(labels).toContain("Unassigned");
    expect(out.groups[0].label).toBe("Multi-repo");
  });

  it("merges unassigned into single repo group", () => {
    const tasks = [task({ id: "a", repositoryPath: "org/only" }), task({ id: "b" })];
    const out = applyGroup(tasks, "repository");
    expect(out.groups).toHaveLength(1);
    expect(out.groups[0].label).toBe("org/only");
    expect(out.groups[0].tasks).toHaveLength(2);
  });

  it("separates subtasks from root tasks", () => {
    const tasks = [
      task({ id: "parent", repositoryPath: "r" }),
      task({ id: "child", repositoryPath: "r", parentTaskId: "parent" }),
      task({ id: "orphan", repositoryPath: "r", parentTaskId: "ghost" }),
    ];
    const out = applyGroup(tasks, "repository");
    expect(out.groups[0].tasks.map((t) => t.id).sort()).toEqual(["orphan", "parent"]);
    expect(out.subTasksByParentId.get("parent")?.map((t) => t.id)).toEqual(["child"]);
  });

  it("groups by workflow / workflowStep / executorType / state", () => {
    const tasks = [
      task({ id: "a", workflowId: "wf1", workflowStepId: "s1", remoteExecutorType: "sprites" }),
      task({ id: "b", workflowId: "wf2", workflowStepId: "s2", remoteExecutorType: "local_pc" }),
    ];
    expect(applyGroup(tasks, "workflow").groups).toHaveLength(2);
    expect(applyGroup(tasks, "workflowStep").groups).toHaveLength(2);
    expect(applyGroup(tasks, "executorType").groups).toHaveLength(2);
  });

  it("buckets missing group-key value into Unassigned", () => {
    const tasks = [task({ id: "a", workflowId: "wf1" }), task({ id: "b" })];
    const out = applyGroup(tasks, "workflow");
    const labels = out.groups.map((g) => g.label);
    expect(labels).toContain("Unassigned");
  });

  it("labels workflow groups with workflowName when available", () => {
    const tasks = [
      task({ id: "a", workflowId: "wf1", workflowName: "Kanban" }),
      task({ id: "b", workflowId: "wf2", workflowName: "PR Reviews" }),
    ];
    const labels = applyGroup(tasks, "workflow")
      .groups.map((g) => g.label)
      .sort();
    expect(labels).toEqual(["Kanban", "PR Reviews"]);
  });

  it("labels workflowStep groups with workflowStepTitle when available", () => {
    const tasks = [
      task({ id: "a", workflowStepId: "s1", workflowStepTitle: "Backlog" }),
      task({ id: "b", workflowStepId: "s2", workflowStepTitle: "In Progress" }),
    ];
    const labels = applyGroup(tasks, "workflowStep")
      .groups.map((g) => g.label)
      .sort();
    expect(labels).toEqual(["Backlog", "In Progress"]);
  });
});

describe("applyView (integration)", () => {
  it("applies filter + sort + group in sequence", () => {
    const view: SidebarView = {
      id: "v",
      name: "v",
      filters: [{ id: "f1", dimension: "isPRReview", op: "is", value: false }],
      sort: { key: "updatedAt", direction: "desc" },
      group: "none",
      collapsedGroups: [],
    };
    const tasks = [
      task({ id: "a", isPRReview: true, updatedAt: "2026-04-05" }),
      task({ id: "b", updatedAt: "2026-04-01" }),
      task({ id: "c", updatedAt: "2026-04-10" }),
    ];
    const out = applyView(tasks, view);
    expect(out.groups).toHaveLength(1);
    expect(out.groups[0].tasks.map((t) => t.id)).toEqual(["c", "b"]);
  });
});

describe("applyView — pinned tasks", () => {
  const titleAscView: SidebarView = {
    id: "v",
    name: "v",
    filters: [],
    sort: { key: "title", direction: "asc" },
    group: "none",
    collapsedGroups: [],
  };

  it("floats pinned tasks to top of group regardless of sort", () => {
    const tasks = [
      task({ id: "a", title: "Alpha" }),
      task({ id: "b", title: "Beta" }),
      task({ id: "c", title: "Gamma" }),
    ];
    const out = applyView(tasks, titleAscView, { pinnedTaskIds: ["c"], orderedTaskIds: [] });
    expect(out.groups[0].tasks.map((t) => t.id)).toEqual(["c", "a", "b"]);
  });

  it("preserves pin order among pinned tasks", () => {
    const tasks = [
      task({ id: "a", title: "Alpha" }),
      task({ id: "b", title: "Beta" }),
      task({ id: "c", title: "Gamma" }),
    ];
    const out = applyView(tasks, titleAscView, { pinnedTaskIds: ["c", "a"], orderedTaskIds: [] });
    expect(out.groups[0].tasks.map((t) => t.id)).toEqual(["c", "a", "b"]);
  });

  it("noop when no tasks are pinned", () => {
    const tasks = [task({ id: "a", title: "Alpha" }), task({ id: "b", title: "Beta" })];
    const out = applyView(tasks, titleAscView, { pinnedTaskIds: [], orderedTaskIds: [] });
    expect(out.groups[0].tasks.map((t) => t.id)).toEqual(["a", "b"]);
  });

  it("applies pin per-group when grouping is active", () => {
    const view: SidebarView = { ...titleAscView, group: "workflow" };
    const tasks = [
      task({ id: "a", title: "Alpha", workflowId: "w1", workflowName: "W1" }),
      task({ id: "b", title: "Beta", workflowId: "w1", workflowName: "W1" }),
      task({ id: "c", title: "Gamma", workflowId: "w2", workflowName: "W2" }),
      task({ id: "d", title: "Delta", workflowId: "w2", workflowName: "W2" }),
    ];
    const out = applyView(tasks, view, { pinnedTaskIds: ["b", "d"], orderedTaskIds: [] });
    const w1 = out.groups.find((g) => g.label === "W1");
    const w2 = out.groups.find((g) => g.label === "W2");
    expect(w1?.tasks.map((t) => t.id)).toEqual(["b", "a"]);
    expect(w2?.tasks.map((t) => t.id)).toEqual(["d", "c"]);
  });

  it("subtasks remain anchored to parent regardless of pin", () => {
    const tasks = [
      task({ id: "p1", title: "P1" }),
      task({ id: "c1", title: "C1", parentTaskId: "p1" }),
      task({ id: "p2", title: "P2" }),
    ];
    const out = applyView(tasks, titleAscView, { pinnedTaskIds: ["p2"], orderedTaskIds: [] });
    // root tasks: p2 pinned first, then p1
    expect(out.groups[0].tasks.map((t) => t.id)).toEqual(["p2", "p1"]);
    // subtasks unchanged
    expect(out.subTasksByParentId.get("p1")?.map((t) => t.id)).toEqual(["c1"]);
  });
});

describe("applyView — custom sort", () => {
  const customView: SidebarView = {
    id: "v",
    name: "v",
    filters: [],
    sort: { key: "custom", direction: "asc" },
    group: "none",
    collapsedGroups: [],
  };

  it("orders tasks by index in orderedTaskIds", () => {
    const tasks = [
      task({ id: "a", title: "Alpha" }),
      task({ id: "b", title: "Beta" }),
      task({ id: "c", title: "Gamma" }),
    ];
    const out = applyView(tasks, customView, {
      pinnedTaskIds: [],
      orderedTaskIds: ["c", "a", "b"],
    });
    expect(out.groups[0].tasks.map((t) => t.id)).toEqual(["c", "a", "b"]);
  });

  it("places tasks not in orderedTaskIds after listed ones, newest createdAt first", () => {
    const tasks = [
      task({ id: "a", title: "Alpha", createdAt: "2026-01-01" }),
      task({ id: "b", title: "Beta", createdAt: "2026-04-01" }),
      task({ id: "c", title: "Gamma", createdAt: "2026-02-01" }),
    ];
    const out = applyView(tasks, customView, { pinnedTaskIds: [], orderedTaskIds: ["c"] });
    expect(out.groups[0].tasks.map((t) => t.id)).toEqual(["c", "b", "a"]);
  });

  it("pinned tasks still float to top within the custom sort", () => {
    const tasks = [
      task({ id: "a", title: "Alpha" }),
      task({ id: "b", title: "Beta" }),
      task({ id: "c", title: "Gamma" }),
    ];
    const out = applyView(tasks, customView, {
      pinnedTaskIds: ["b"],
      orderedTaskIds: ["c", "a", "b"],
    });
    expect(out.groups[0].tasks.map((t) => t.id)).toEqual(["b", "c", "a"]);
  });

  it("direction=desc on custom sort does NOT reverse the manual order", () => {
    const descView: SidebarView = { ...customView, sort: { key: "custom", direction: "desc" } };
    const tasks = [
      task({ id: "a", title: "Alpha" }),
      task({ id: "b", title: "Beta" }),
      task({ id: "c", title: "Gamma" }),
    ];
    const out = applyView(tasks, descView, {
      pinnedTaskIds: [],
      orderedTaskIds: ["c", "a", "b"],
    });
    // Same as direction=asc — the manual order is intentional, direction does not flip it
    expect(out.groups[0].tasks.map((t) => t.id)).toEqual(["c", "a", "b"]);
  });

  it("reordering a parent moves it but its subtasks stay anchored beneath it", () => {
    const tasks = [
      task({ id: "p1", title: "P1", createdAt: "2026-01-01" }),
      task({ id: "p2", title: "P2", createdAt: "2026-01-02" }),
      task({ id: "p3", title: "P3", createdAt: "2026-01-03" }),
      task({ id: "c1", title: "C1", parentTaskId: "p1", createdAt: "2026-02-01" }),
      task({ id: "c2", title: "C2", parentTaskId: "p1", createdAt: "2026-02-02" }),
    ];
    // Simulates a drag of P3 to the front. orderedTaskIds contains only root
    // IDs here; subtasks fall back to "newest createdAt first".
    const out = applyView(tasks, customView, {
      pinnedTaskIds: [],
      orderedTaskIds: ["p3", "p1", "p2"],
    });
    // Root order matches the drag.
    expect(out.groups[0].tasks.map((t) => t.id)).toEqual(["p3", "p1", "p2"]);
    // Subtasks stay attached to p1 and use the createdAt fallback (newest
    // first) since neither is in orderedTaskIds.
    expect(out.subTasksByParentId.get("p1")?.map((t) => t.id)).toEqual(["c2", "c1"]);
    expect(out.subTasksByParentId.get("p2")).toBeUndefined();
    expect(out.subTasksByParentId.get("p3")).toBeUndefined();
  });

  it("non-custom sorts ignore orderedTaskIds", () => {
    const titleView: SidebarView = { ...customView, sort: { key: "title", direction: "asc" } };
    const tasks = [
      task({ id: "a", title: "Alpha" }),
      task({ id: "b", title: "Beta" }),
      task({ id: "c", title: "Gamma" }),
    ];
    const out = applyView(tasks, titleView, {
      pinnedTaskIds: [],
      orderedTaskIds: ["c", "b", "a"],
    });
    expect(out.groups[0].tasks.map((t) => t.id)).toEqual(["a", "b", "c"]);
  });
});

describe("applyView — subtaskOrderByParentId", () => {
  // Subtask ordering is independent of the view's sort: the global sort still
  // determines root order, and per-parent overrides reorder *only* that parent's
  // subtask list.
  const titleAscView: SidebarView = {
    id: "v",
    name: "v",
    filters: [],
    sort: { key: "title", direction: "asc" },
    group: "none",
    collapsedGroups: [],
  };
  const parentId = "p1";
  const sub = (id: string, parent: string) => task({ id, title: id, parentTaskId: parent });

  it("reorders one parent's subtasks without flipping the root sort", () => {
    const tasks = [
      task({ id: "p1", title: "P1" }),
      task({ id: "p2", title: "P2" }),
      sub("c1", parentId),
      sub("c2", parentId),
      sub("c3", parentId),
    ];
    const out = applyView(tasks, titleAscView, {
      pinnedTaskIds: [],
      orderedTaskIds: [],
      subtaskOrderByParentId: { [parentId]: ["c1", "c3", "c2"] },
    });
    // Root order still follows title asc — untouched by the subtask reorder.
    expect(out.groups[0].tasks.map((t) => t.id)).toEqual(["p1", "p2"]);
    expect(out.subTasksByParentId.get(parentId)?.map((t) => t.id)).toEqual(["c1", "c3", "c2"]);
  });

  it("subtasks not in the override keep the active sort's order, after the listed ones", () => {
    const tasks = [
      task({ id: "p1", title: "P1" }),
      sub("c1", parentId),
      sub("c2", parentId),
      sub("c3", parentId),
    ];
    // Title-asc fallback over the unordered subtasks: c1, c2 follow after c3.
    const out = applyView(tasks, titleAscView, {
      pinnedTaskIds: [],
      orderedTaskIds: [],
      subtaskOrderByParentId: { [parentId]: ["c3"] },
    });
    expect(out.subTasksByParentId.get(parentId)?.map((t) => t.id)).toEqual(["c3", "c1", "c2"]);
  });

  it("override for parent A does not affect parent B's subtasks", () => {
    const tasks = [
      task({ id: "p1", title: "P1" }),
      task({ id: "p2", title: "P2" }),
      sub("a1", "p1"),
      sub("a2", "p1"),
      sub("b1", "p2"),
      sub("b2", "p2"),
    ];
    const out = applyView(tasks, titleAscView, {
      pinnedTaskIds: [],
      orderedTaskIds: [],
      subtaskOrderByParentId: { p1: ["a2", "a1"] },
    });
    expect(out.subTasksByParentId.get("p1")?.map((t) => t.id)).toEqual(["a2", "a1"]);
    expect(out.subTasksByParentId.get("p2")?.map((t) => t.id)).toEqual(["b1", "b2"]);
  });
});

describe("mergeGroupOrder", () => {
  it("appends when no group items are in current", () => {
    expect(mergeGroupOrder([], ["a", "b"])).toEqual(["a", "b"]);
    expect(mergeGroupOrder(["x", "y"], ["a", "b"])).toEqual(["x", "y", "a", "b"]);
  });

  it("anchors at the first occurrence of any group item", () => {
    expect(mergeGroupOrder(["x", "a", "y", "b"], ["b", "a"])).toEqual(["x", "b", "a", "y"]);
  });

  it("does not move other-group tasks on a repeated drag in the same group", () => {
    // First drag: group A reordered. Second drag: group A reordered again.
    // The relative order of A vs B (and the position of A's section) must stay stable.
    const afterFirst = mergeGroupOrder([], ["a1", "a2", "a3"]);
    expect(afterFirst).toEqual(["a1", "a2", "a3"]);
    const afterSecondGroupB = mergeGroupOrder(afterFirst, ["b1", "b2"]);
    expect(afterSecondGroupB).toEqual(["a1", "a2", "a3", "b1", "b2"]);
    // Now drag A again — A must NOT move to the end (the original bug).
    const afterThirdGroupA = mergeGroupOrder(afterSecondGroupB, ["a3", "a1", "a2"]);
    expect(afterThirdGroupA).toEqual(["a3", "a1", "a2", "b1", "b2"]);
    // And dragging B again must keep A first.
    const afterFourthGroupB = mergeGroupOrder(afterThirdGroupA, ["b2", "b1"]);
    expect(afterFourthGroupB).toEqual(["a3", "a1", "a2", "b2", "b1"]);
  });
});

describe("default view semantics", () => {
  it("default view shows everything, grouped by repository", () => {
    const tasks = [
      task({
        id: "pr-open",
        prInfo: { number: 1, state: "Open" },
        state: "REVIEW",
        repositoryPath: "org/r",
      }),
      task({ id: "plain", state: "IN_PROGRESS", repositoryPath: "org/r" }),
      task({ id: "archived", isArchived: true, repositoryPath: "org/r" }),
    ];
    const out = applyView(tasks, DEFAULT_VIEW);
    const ids = out.groups.flatMap((g) => g.tasks.map((t) => t.id));
    expect(ids.sort()).toEqual(["archived", "plain", "pr-open"]);
  });
});