Give each task an assigned colour across the UI; lead links tasks

internal/store/color_test.go

@@ -0,0 +1,60 @@
+package store_test
+
+import (
+	"context"
+	"fmt"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"g.fc.run/misc/byre/internal/api"
+	"g.fc.run/misc/byre/internal/store"
+)
+
+func TestTaskColorsAvoidActiveAndRecent(t *testing.T) {
+	ctx := context.Background()
+	st, err := store.Open(filepath.Join(t.TempDir(), "byre.db"), 51000, func(api.Event) {})
+	if err != nil {
+		t.Fatalf("open store: %v", err)
+	}
+	t.Cleanup(func() { st.Close() })
+
+	now := time.Now().UTC()
+	_, err = st.EnsureUser(ctx, "alice", "Alice")
+	if err != nil {
+		t.Fatalf("ensure user: %v", err)
+	}
+	err = st.CreateProject(ctx, api.Project{Id: "p1", Name: "demo", RepoPath: "/nonexistent", DefaultBranch: "main", Remote: "none", CreatedBy: "alice", CreatedAt: now})
+	if err != nil {
+		t.Fatalf("create project: %v", err)
+	}
+
+	create := func(id string) int {
+		err := st.CreateTask(ctx, api.Task{Id: id, ProjectId: "p1", Title: id, Branch: id, WorktreePath: "/nonexistent", BaseRef: "x", Status: api.TaskStatusActive, CreatedBy: "alice", CreatedAt: now}, "alice")
+		if err != nil {
+			t.Fatalf("create task %s: %v", id, err)
+		}
+		task, err := st.GetTask(ctx, id)
+		if err != nil {
+			t.Fatalf("get task %s: %v", id, err)
+		}
+		return task.Color
+	}
+
+	if c1, c2 := create("t1"), create("t2"); c1 != 0 || c2 != 1 {
+		t.Fatalf("colors = %d, %d, want 0, 1", c1, c2)
+	}
+	_, err = st.DiscardTask(ctx, "t1", "alice")
+	if err != nil {
+		t.Fatalf("discard: %v", err)
+	}
+	if c := create("t3"); c != 2 {
+		t.Fatalf("t3 color = %d, want 2, not the just-freed 0", c)
+	}
+	for i := 4; i <= store.TaskColors; i++ {
+		create(fmt.Sprintf("t%d", i))
+	}
+	if c := create("t12"); c != 0 {
+		t.Fatalf("t12 color = %d, want 0, the only one no active task holds", c)
+	}
+}

internal/store/store.go

@@ -280,11 +280,18 @@ CREATE TABLE previews (
 	PRIMARY KEY (task_id, name),
 	UNIQUE (task_id, port)
 );
+`}, {"add-task-color", `
+ALTER TABLE tasks ADD COLUMN color INTEGER NOT NULL DEFAULT 0;
+UPDATE tasks SET color = (SELECT count(*) FROM tasks AS earlier WHERE earlier.rowid < tasks.rowid) % 11;
+UPDATE tasks SET color = (
+	SELECT count(*) FROM tasks AS earlier WHERE earlier.status = 'active' AND earlier.rowid < tasks.rowid
+) % 11 WHERE status = 'active';
 `}}
 
 const (
 	DefaultPortFirst = 41000
 	PortBlock        = 10
+	TaskColors       = 11
 )
 
 type Store struct {
@@ -571,10 +578,19 @@ func (s *Store) CreateTask(ctx context.Context, t api.Task, actor string) error
 		if err != nil {
 			return err
 		}
+		err = tx.QueryRowContext(ctx, `
+			WITH RECURSIVE palette(c) AS (SELECT 0 UNION ALL SELECT c + 1 FROM palette WHERE c + 1 < ?)
+			SELECT c FROM palette
+			ORDER BY c IN (SELECT color FROM tasks WHERE status = ?), coalesce((SELECT max(rowid) FROM tasks WHERE color = c), -1), c
+			LIMIT 1
+		`, TaskColors, string(api.TaskStatusActive)).Scan(&t.Color)
+		if err != nil {
+			return err
+		}
 		_, err = tx.ExecContext(ctx, `
-			INSERT INTO tasks (id, project_id, title, merge_title, branch, worktree_path, base_ref, port_base, status, created_by, created_at, todo_item, forked_from, forked_at)
-			VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
-		`, t.Id, t.ProjectId, t.Title, mergeTitle, t.Branch, t.WorktreePath, t.BaseRef, t.PortBase, string(t.Status), t.CreatedBy, formatTime(t.CreatedAt), todoItem, forkedFrom, forkedAt)
+			INSERT INTO tasks (id, project_id, title, merge_title, branch, worktree_path, base_ref, port_base, color, status, created_by, created_at, todo_item, forked_from, forked_at)
+			VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+		`, t.Id, t.ProjectId, t.Title, mergeTitle, t.Branch, t.WorktreePath, t.BaseRef, t.PortBase, t.Color, string(t.Status), t.CreatedBy, formatTime(t.CreatedAt), todoItem, forkedFrom, forkedAt)
 		if err != nil {
 			return err
 		}
@@ -1090,7 +1106,7 @@ func (s *Store) write(ctx context.Context, fn func(tx *sql.Tx, emit emitFunc) er
 
 const projectColumns = `id, name, repo_path, default_branch, remote, created_by, created_at`
 
-const taskColumns = `id, project_id, title, merge_title, branch, worktree_path, base_ref, port_base, status, created_by, created_at, closed_at, merge_commit, todo_item, forked_from, forked_at, merge_queued_at`
+const taskColumns = `id, project_id, title, merge_title, branch, worktree_path, base_ref, port_base, color, status, created_by, created_at, closed_at, merge_commit, todo_item, forked_from, forked_at, merge_queued_at`
 
 const sessionColumns = `id, coalesce(task_id, ''), owner, vendor, model, vendor_session_id, state, role, created_by, created_at, forked_from, forked_at`
 
@@ -1119,7 +1135,7 @@ func scanTask(row scanner) (api.Task, error) {
 	forkedFrom := ""
 	forkedAt := 0
 	mergeQueuedAt := ""
-	err := row.Scan(&t.Id, &t.ProjectId, &t.Title, &t.MergeTitle, &t.Branch, &t.WorktreePath, &t.BaseRef, &t.PortBase, &status, &t.CreatedBy, &createdAt, &closedAt, &mergeCommit, &todoItem, &forkedFrom, &forkedAt, &mergeQueuedAt)
+	err := row.Scan(&t.Id, &t.ProjectId, &t.Title, &t.MergeTitle, &t.Branch, &t.WorktreePath, &t.BaseRef, &t.PortBase, &t.Color, &status, &t.CreatedBy, &createdAt, &closedAt, &mergeCommit, &todoItem, &forkedFrom, &forkedAt, &mergeQueuedAt)
 	if err != nil {
 		return t, err
 	}