Add persistent history stacks

src/db/repositories/circuit-device-row-project-command.repository.ts

@@ -21,6 +21,7 @@ import {
   toCircuitDeviceRowPatchValues,
   type CircuitDeviceRowPatchInput,
 } from "./circuit-device-row.persistence.js";
+import { applyProjectHistoryTransition } from "./project-history.persistence.js";
 import { appendProjectRevision } from "./project-revision.persistence.js";
 
 type CircuitDeviceRow = typeof circuitDeviceRows.$inferSelect;
@@ -117,6 +118,12 @@ export class CircuitDeviceRowProjectCommandRepository
         forward: appliedForward,
         inverse,
       });
+      applyProjectHistoryTransition(tx, {
+        projectId: input.projectId,
+        source: input.source,
+        recordedChangeSetId: revision.changeSetId,
+        targetChangeSetId: input.historyTargetChangeSetId,
+      });
 
       return { revision, inverse };
     });

src/db/repositories/circuit-project-command.repository.ts

@@ -18,6 +18,7 @@ import {
   toCircuitPatchValues,
   type CircuitPatchPersistenceInput,
 } from "./circuit.persistence.js";
+import { applyProjectHistoryTransition } from "./project-history.persistence.js";
 import { appendProjectRevision } from "./project-revision.persistence.js";
 
 type CircuitRow = typeof circuits.$inferSelect;
@@ -96,6 +97,12 @@ export class CircuitProjectCommandRepository
         forward: input.command,
         inverse,
       });
+      applyProjectHistoryTransition(tx, {
+        projectId: input.projectId,
+        source: input.source,
+        recordedChangeSetId: revision.changeSetId,
+        targetChangeSetId: input.historyTargetChangeSetId,
+      });
 
       return { revision, inverse };
     });

src/db/repositories/project-history.persistence.ts

@@ -0,0 +1,121 @@
+import { and, desc, eq, max } from "drizzle-orm";
+import type { ProjectRevisionSource } from "../../domain/ports/project-revision.store.js";
+import type { AppDatabase } from "../database-context.js";
+import { projectHistoryStackEntries } from "../schema/project-history-stack-entries.js";
+
+export interface ApplyProjectHistoryTransitionInput {
+  projectId: string;
+  source: ProjectRevisionSource;
+  recordedChangeSetId: string;
+  targetChangeSetId?: string;
+}
+
+export function applyProjectHistoryTransition(
+  database: AppDatabase,
+  input: ApplyProjectHistoryTransitionInput
+) {
+  if (input.source === "user") {
+    database
+      .delete(projectHistoryStackEntries)
+      .where(
+        and(
+          eq(projectHistoryStackEntries.projectId, input.projectId),
+          eq(projectHistoryStackEntries.stack, "redo")
+        )
+      )
+      .run();
+    push(
+      database,
+      input.projectId,
+      input.recordedChangeSetId,
+      "undo"
+    );
+    return;
+  }
+
+  if (input.source === "undo" || input.source === "redo") {
+    if (!input.targetChangeSetId) {
+      throw new Error(
+        `${input.source} requires a target change set.`
+      );
+    }
+    const sourceStack = input.source;
+    const targetStack = input.source === "undo" ? "redo" : "undo";
+    const top = database
+      .select({
+        changeSetId: projectHistoryStackEntries.changeSetId,
+      })
+      .from(projectHistoryStackEntries)
+      .where(
+        and(
+          eq(projectHistoryStackEntries.projectId, input.projectId),
+          eq(projectHistoryStackEntries.stack, sourceStack)
+        )
+      )
+      .orderBy(desc(projectHistoryStackEntries.position))
+      .limit(1)
+      .get();
+    if (!top || top.changeSetId !== input.targetChangeSetId) {
+      throw new Error(
+        `${input.source} target is not the top ${sourceStack} command.`
+      );
+    }
+
+    const nextPosition = getNextPosition(
+      database,
+      input.projectId,
+      targetStack
+    );
+    const moved = database
+      .update(projectHistoryStackEntries)
+      .set({ stack: targetStack, position: nextPosition })
+      .where(
+        and(
+          eq(projectHistoryStackEntries.projectId, input.projectId),
+          eq(
+            projectHistoryStackEntries.changeSetId,
+            input.targetChangeSetId
+          )
+        )
+      )
+      .run();
+    if (moved.changes !== 1) {
+      throw new Error("Project history stack changed during transition.");
+    }
+  }
+}
+
+function push(
+  database: AppDatabase,
+  projectId: string,
+  changeSetId: string,
+  stack: "undo" | "redo"
+) {
+  database
+    .insert(projectHistoryStackEntries)
+    .values({
+      projectId,
+      changeSetId,
+      stack,
+      position: getNextPosition(database, projectId, stack),
+    })
+    .run();
+}
+
+function getNextPosition(
+  database: AppDatabase,
+  projectId: string,
+  stack: "undo" | "redo"
+) {
+  const current = database
+    .select({ position: max(projectHistoryStackEntries.position) })
+    .from(projectHistoryStackEntries)
+    .where(
+      and(
+        eq(projectHistoryStackEntries.projectId, projectId),
+        eq(projectHistoryStackEntries.stack, stack)
+      )
+    )
+    .get();
+  return (current?.position ?? 0) + 1;
+}

src/db/repositories/project-history.repository.ts

@@ -0,0 +1,44 @@
+import { asc, eq } from "drizzle-orm";
+import type {
+  ProjectHistoryState,
+  ProjectHistoryStore,
+} from "../../domain/ports/project-history.store.js";
+import type { AppDatabase } from "../database-context.js";
+import { projectHistoryStackEntries } from "../schema/project-history-stack-entries.js";
+import { projects } from "../schema/projects.js";
+
+export class ProjectHistoryRepository implements ProjectHistoryStore {
+  constructor(private readonly database: AppDatabase) {}
+
+  getState(projectId: string): ProjectHistoryState | null {
+    const project = this.database
+      .select({ currentRevision: projects.currentRevision })
+      .from(projects)
+      .where(eq(projects.id, projectId))
+      .get();
+    if (!project) {
+      return null;
+    }
+
+    const entries = this.database
+      .select()
+      .from(projectHistoryStackEntries)
+      .where(eq(projectHistoryStackEntries.projectId, projectId))
+      .orderBy(
+        asc(projectHistoryStackEntries.stack),
+        asc(projectHistoryStackEntries.position)
+      )
+      .all();
+    const undoEntries = entries.filter((entry) => entry.stack === "undo");
+    const redoEntries = entries.filter((entry) => entry.stack === "redo");
+
+    return {
+      projectId,
+      currentRevision: project.currentRevision,
+      undoDepth: undoEntries.length,
+      redoDepth: redoEntries.length,
+      undoChangeSetId: undoEntries.at(-1)?.changeSetId ?? null,
+      redoChangeSetId: redoEntries.at(-1)?.changeSetId ?? null,
+    };
+  }
+}