rhythm-backend/BACKEND_BLUEPRINT.md

# Rhythm Backend Blueprint (Rust/Axum)

## IDEAS
- instead of elastic search use ts vector and ts query to allow easy issue searching for smooth experience
- YouTrack competitor: issue tracker with organizations, projects, issues, and project-level RBAC

---

## Chosen Stack

- **Language:** Rust (edition 2024)
- **Framework:** Axum
- **Runtime:** Tokio
- **Migrations:** sqlx built-in migrations
- **DB Access:** sqlx (compile-time checked queries, hand-written repositories)
- **PostgreSQL Driver/Pool:** sqlx::PgPool
- **Logging:** tracing + tracing-subscriber + tracing-tree (structured, hierarchical)
- **Auth:** jsonwebtoken (HS256) + argon2 (password hashing)
- **API Docs:** utoipa (code-first OpenAPI generation)
- **Health Probes:** liveness/readiness endpoints
- **Deployment:** Docker Compose on self-hosted hardware

---

## Decisions Made

1. **JWT signing:** HS256 (shared secret from env, can migrate to RS256 later)
2. **Token model:** Access + Refresh (short-lived access ~15min, long-lived refresh ~7d, refresh tokens stored hashed in DB)
3. **Roles:** Project-level roles (`admin`, `developer`, `reporter`) + Org-level roles (`owner`, `admin`, `member`)
4. **OpenAPI workflow:** Code-first with utoipa (auto-generate spec from Rust handlers/models)
5. **DB access:** sqlx with hand-written repositories (compile-time checked, no ORM)
6. **First entities:** Users → Organizations → Projects → Issues
7. **Sprint stages:** Custom per project (project admin defines board columns like Todo → In Review → Done)
8. **Assignees:** Multiple assignees per issue (join table)
9. **Issue content features:** Tags, comments, issue relations, time tracking
10. **Plugin system:** Lua scripting with cron + event-driven triggers (Phase 7)

---

## Architecture Direction

### Project Structure

```
src/
├── main.rs              # Entrypoint, server, graceful shutdown
├── config.rs            # Config (exists, extend)
├── logging.rs           # Logging (exists)
├── errors.rs            # Unified error types → Axum responses
├── state.rs             # AppState (PgPool, config, etc.)
├── routes.rs            # Router composition (/api/v1/...)
├── auth/
│   ├── jwt.rs           # HS256 token creation/validation
│   ├── hash.rs          # argon2 password hashing
│   ├── handlers.rs      # register, login, refresh
│   ├── models.rs        # auth DTOs
│   └── service.rs       # auth business logic
├── middleware/
│   ├── auth.rs          # JWT extraction layer
│   └── rbac.rs          # Project-level role guard
├── models/
│   ├── user.rs
│   ├── org.rs
│   ├── project.rs
│   ├── issue.rs
│   ├── comment.rs
│   ├── tag.rs
│   ├── sprint.rs
│   ├── stage.rs
│   ├── time_entry.rs
│   └── role.rs          # OrgRole, ProjectRole enums
├── handlers/
│   ├── health.rs
│   ├── orgs.rs
│   ├── projects.rs
│   ├── issues.rs
│   ├── comments.rs
│   ├── tags.rs
│   ├── sprints.rs
│   ├── stages.rs
│   └── time_entries.rs
├── services/
│   ├── org.rs
│   ├── project.rs
│   ├── issue.rs
│   ├── comment.rs
│   ├── tag.rs
│   ├── sprint.rs
│   ├── stage.rs
│   └── time_entry.rs
└── db/
    ├── mod.rs            # Pool setup, migration runner
    └── repos/
        ├── users.rs
        ├── orgs.rs
        ├── projects.rs
        ├── issues.rs
        ├── comments.rs
        ├── tags.rs
        ├── sprints.rs
        ├── stages.rs
        ├── time_entries.rs
        ├── memberships.rs
        └── refresh_tokens.rs
migrations/
├── 001_create_users.sql
├── 002_create_organizations.sql
├── 003_create_memberships.sql
├── 004_create_projects.sql
├── 005_create_stages.sql
├── 006_create_issues.sql
├── 007_create_issue_assignees.sql
├── 008_create_tags.sql
├── 009_create_comments.sql
├── 010_create_issue_relations.sql
├── 011_create_time_entries.sql
├── 012_create_sprints.sql
├── 013_create_refresh_tokens.sql
└── 014_add_tsvector_search.sql
```

### Layering Principles

- Handlers stay thin — they extract, validate, call service, respond
- Service layer owns business logic + DB transactions
- Repositories own SQL queries (sqlx compile-time checked)
- No transaction logic in handlers
- AppState shared via Axum's State extractor

### Transaction Strategy

- Service layer owns DB transactions
- Repositories accept either `&PgPool` or `&mut Transaction<Postgres>`
- sqlx compile-time query checking ensures SQL correctness at build time

---

## API and Runtime

### API Shape

- REST JSON API
- Possible future WebSocket support for interactive features
- Versioning: `/api/v1`

### Health Endpoints

- `GET /api/v1/health/live` - process is alive
- `GET /api/v1/health/ready` - DB ping succeeds (and optionally migration version check)

### Auth Endpoints

- `POST /api/v1/auth/register` - create account (email + password)
- `POST /api/v1/auth/login` - get access + refresh tokens
- `POST /api/v1/auth/refresh` - rotate refresh token

### Organization Endpoints

- `POST /api/v1/orgs` - create org (creator becomes owner)
- `GET /api/v1/orgs` - list user's orgs
- `GET /api/v1/orgs/{org_slug}` - get org
- `PATCH /api/v1/orgs/{org_slug}` - update org (owner/admin)
- `DELETE /api/v1/orgs/{org_slug}` - delete org (owner)

### Project Endpoints

- `POST /api/v1/orgs/{org_slug}/projects` - create project (org owner/admin)
- `GET /api/v1/orgs/{org_slug}/projects` - list projects
- `GET /api/v1/orgs/{org_slug}/projects/{project_slug}` - get project
- `PATCH /api/v1/orgs/{org_slug}/projects/{project_slug}` - update project (project admin)
- `DELETE /api/v1/orgs/{org_slug}/projects/{project_slug}` - delete project (project admin)

### Issue Endpoints

- `POST /api/v1/orgs/{org_slug}/projects/{project_slug}/issues` - create issue (reporter+)
- `GET /api/v1/orgs/{org_slug}/projects/{project_slug}/issues` - list issues (with `?q=` search, `?tag=`, `?assignee=`, `?status=`)
- `GET /api/v1/orgs/{org_slug}/projects/{project_slug}/issues/{number}` - get issue
- `PATCH /api/v1/orgs/{org_slug}/projects/{project_slug}/issues/{number}` - update issue (developer+)
- `DELETE /api/v1/orgs/{org_slug}/projects/{project_slug}/issues/{number}` - delete issue (admin)

### Issue Sub-resource Endpoints

**Tags:**
- `GET /api/v1/orgs/{org}/projects/{proj}/tags` - list project tags
- `POST /api/v1/orgs/{org}/projects/{proj}/tags` - create tag (developer+)
- `DELETE /api/v1/orgs/{org}/projects/{proj}/tags/{tag_id}` - delete tag (admin)
- `PUT /api/v1/orgs/{org}/projects/{proj}/issues/{num}/tags` - set issue tags (developer+)

**Comments:**
- `GET /api/v1/orgs/{org}/projects/{proj}/issues/{num}/comments` - list comments
- `POST /api/v1/orgs/{org}/projects/{proj}/issues/{num}/comments` - add comment (reporter+)
- `PATCH /api/v1/orgs/{org}/projects/{proj}/issues/{num}/comments/{id}` - edit comment (author only)
- `DELETE /api/v1/orgs/{org}/projects/{proj}/issues/{num}/comments/{id}` - delete comment (author or admin)

**Assignees:**
- `GET /api/v1/orgs/{org}/projects/{proj}/issues/{num}/assignees` - list assignees
- `PUT /api/v1/orgs/{org}/projects/{proj}/issues/{num}/assignees` - set assignees (developer+)

**Relations:**
- `GET /api/v1/orgs/{org}/projects/{proj}/issues/{num}/relations` - list relations
- `POST /api/v1/orgs/{org}/projects/{proj}/issues/{num}/relations` - add relation (developer+)
- `DELETE /api/v1/orgs/{org}/projects/{proj}/issues/{num}/relations/{id}` - remove relation (developer+)

**Time Tracking:**
- `GET /api/v1/orgs/{org}/projects/{proj}/issues/{num}/time-entries` - list time entries
- `POST /api/v1/orgs/{org}/projects/{proj}/issues/{num}/time-entries` - log time (developer+)
- `DELETE /api/v1/orgs/{org}/projects/{proj}/issues/{num}/time-entries/{id}` - delete entry (author or admin)

### Sprint Endpoints

- `POST /api/v1/orgs/{org}/projects/{proj}/sprints` - create sprint (developer+)
- `GET /api/v1/orgs/{org}/projects/{proj}/sprints` - list sprints
- `GET /api/v1/orgs/{org}/projects/{proj}/sprints/{id}` - get sprint
- `PATCH /api/v1/orgs/{org}/projects/{proj}/sprints/{id}` - update sprint (developer+)
- `PATCH /api/v1/orgs/{org}/projects/{proj}/sprints/{id}/start` - start sprint (admin)
- `PATCH /api/v1/orgs/{org}/projects/{proj}/sprints/{id}/complete` - complete sprint (admin)
- `GET /api/v1/orgs/{org}/projects/{proj}/sprints/{id}/board` - sprint board (issues grouped by stage)

### Stage Endpoints (project board columns)

- `POST /api/v1/orgs/{org}/projects/{proj}/stages` - create stage (admin)
- `PATCH /api/v1/orgs/{org}/projects/{proj}/stages` - reorder stages (admin)
- `DELETE /api/v1/orgs/{org}/projects/{proj}/stages/{id}` - delete stage (admin)

### Logging

- tracing with hierarchical layer (dev: pretty console, prod: JSON + file with rotation)
- Correlation/request ID in middleware
- Structured error logging from middleware and service boundaries

---

## Database Schema

```sql
-- Enums
CREATE TYPE org_role AS ENUM ('owner', 'admin', 'member');
CREATE TYPE project_role AS ENUM ('admin', 'developer', 'reporter');
CREATE TYPE issue_status AS ENUM ('open', 'in_progress', 'resolved', 'closed');
CREATE TYPE issue_priority AS ENUM ('critical', 'major', 'normal', 'minor');
CREATE TYPE issue_type AS ENUM ('bug', 'feature', 'task', 'improvement');
CREATE TYPE issue_relation_type AS ENUM ('blocks', 'is_blocked_by', 'duplicates', 'is_duplicated_by', 'relates_to', 'clones', 'is_cloned_by');
CREATE TYPE sprint_status AS ENUM ('planned', 'active', 'completed');
CREATE TYPE trigger_type AS ENUM ('event', 'schedule', 'manual');

-- Users
CREATE TABLE users (
    id            UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    email         TEXT NOT NULL UNIQUE,
    password_hash TEXT NOT NULL,
    display_name  TEXT,
    avatar_url    TEXT,
    created_at    TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at    TIMESTAMPTZ NOT NULL DEFAULT now()
);

-- Organizations
CREATE TABLE organizations (
    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    name        TEXT NOT NULL,
    slug        TEXT NOT NULL UNIQUE,
    description TEXT,
    created_at  TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at  TIMESTAMPTZ NOT NULL DEFAULT now()
);

-- Org memberships (owner/admin/member)
CREATE TABLE org_memberships (
    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id    UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    org_id     UUID NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
    role       org_role NOT NULL DEFAULT 'member',
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    UNIQUE(user_id, org_id)
);

-- Projects
CREATE TABLE projects (
    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    name        TEXT NOT NULL,
    slug        TEXT NOT NULL,
    description TEXT,
    org_id      UUID NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
    created_by  UUID NOT NULL REFERENCES users(id),
    created_at  TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at  TIMESTAMPTZ NOT NULL DEFAULT now(),
    UNIQUE(org_id, slug)
);

-- Project memberships (admin/developer/reporter)
CREATE TABLE project_memberships (
    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id    UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    project_id UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
    role       project_role NOT NULL DEFAULT 'reporter',
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    UNIQUE(user_id, project_id)
);

-- Stages (custom board columns per project)
CREATE TABLE stages (
    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    name       TEXT NOT NULL,
    position   INT NOT NULL,
    project_id UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
    UNIQUE(project_id, position)
);

-- Issues
CREATE TABLE issues (
    id            UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    number        BIGINT NOT NULL,
    title         TEXT NOT NULL,
    description   TEXT,
    status        issue_status NOT NULL DEFAULT 'open',
    priority      issue_priority NOT NULL DEFAULT 'normal',
    issue_type    issue_type NOT NULL DEFAULT 'task',
    project_id    UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
    reporter_id   UUID NOT NULL REFERENCES users(id),
    stage_id      UUID REFERENCES stages(id) ON DELETE SET NULL,
    sprint_id     UUID REFERENCES sprints(id) ON DELETE SET NULL,
    search_vector TSVECTOR GENERATED ALWAYS AS (
        setweight(to_tsvector('english', coalesce(title, '')), 'A') ||
        setweight(to_tsvector('english', coalesce(description, '')), 'B')
    ) STORED,
    created_at    TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at    TIMESTAMPTZ NOT NULL DEFAULT now(),
    UNIQUE(project_id, number)
);

-- Multiple assignees per issue
CREATE TABLE issue_assignees (
    issue_id UUID NOT NULL REFERENCES issues(id) ON DELETE CASCADE,
    user_id  UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    PRIMARY KEY (issue_id, user_id)
);

-- Tags (per project)
CREATE TABLE tags (
    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    name       TEXT NOT NULL,
    color      TEXT,
    project_id UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
    UNIQUE(project_id, name)
);

CREATE TABLE issue_tags (
    issue_id UUID NOT NULL REFERENCES issues(id) ON DELETE CASCADE,
    tag_id   UUID NOT NULL REFERENCES tags(id) ON DELETE CASCADE,
    PRIMARY KEY (issue_id, tag_id)
);

-- Comments
CREATE TABLE comments (
    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    issue_id   UUID NOT NULL REFERENCES issues(id) ON DELETE CASCADE,
    author_id  UUID NOT NULL REFERENCES users(id),
    body       TEXT NOT NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

-- Related issues
CREATE TABLE issue_relations (
    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    from_issue_id   UUID NOT NULL REFERENCES issues(id) ON DELETE CASCADE,
    to_issue_id     UUID NOT NULL REFERENCES issues(id) ON DELETE CASCADE,
    relation_type   issue_relation_type NOT NULL,
    created_at      TIMESTAMPTZ NOT NULL DEFAULT now(),
    UNIQUE(from_issue_id, to_issue_id, relation_type)
);

-- Time tracking
CREATE TABLE time_entries (
    id             UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    issue_id       UUID NOT NULL REFERENCES issues(id) ON DELETE CASCADE,
    user_id        UUID NOT NULL REFERENCES users(id),
    seconds_spent  INTEGER NOT NULL CHECK (seconds_spent > 0),
    description    TEXT,
    logged_at      TIMESTAMPTZ NOT NULL DEFAULT now(),
    created_at     TIMESTAMPTZ NOT NULL DEFAULT now()
);

-- Sprints
CREATE TABLE sprints (
    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    name        TEXT NOT NULL,
    project_id  UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
    starts_at   TIMESTAMPTZ NOT NULL,
    ends_at     TIMESTAMPTZ NOT NULL,
    status      sprint_status NOT NULL DEFAULT 'planned',
    created_at  TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at  TIMESTAMPTZ NOT NULL DEFAULT now()
);

-- Refresh tokens
CREATE TABLE refresh_tokens (
    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id    UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    token_hash TEXT NOT NULL UNIQUE,
    expires_at TIMESTAMPTZ NOT NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

-- Scripts (for Lua plugin system)
CREATE TABLE scripts (
    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    name            TEXT NOT NULL,
    source          TEXT NOT NULL,
    trigger_type    trigger_type NOT NULL,
    trigger_config  JSONB,
    project_id      UUID REFERENCES projects(id) ON DELETE CASCADE,
    org_id          UUID NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
    enabled         BOOLEAN NOT NULL DEFAULT true,
    created_by      UUID NOT NULL REFERENCES users(id),
    created_at      TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at      TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE TABLE script_revisions (
    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    script_id  UUID NOT NULL REFERENCES scripts(id) ON DELETE CASCADE,
    source     TEXT NOT NULL,
    created_by UUID NOT NULL REFERENCES users(id),
    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE TABLE script_execution_logs (
    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    script_id  UUID NOT NULL REFERENCES scripts(id) ON DELETE CASCADE,
    status     TEXT NOT NULL,
    output     TEXT,
    error      TEXT,
    duration_ms INTEGER,
    triggered_by TEXT NOT NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

-- Indexes
CREATE INDEX idx_issues_search ON issues USING GIN(search_vector);
CREATE INDEX idx_issues_project_sprint ON issues(project_id, sprint_id);
CREATE INDEX idx_issues_project_stage ON issues(project_id, stage_id);
CREATE INDEX idx_time_entries_issue ON time_entries(issue_id);
CREATE INDEX idx_comments_issue ON comments(issue_id);
```

**Note:** The `issues` table references `sprints(id)` via `sprint_id`. In practice, the `sprints` table migration must run before `issues` (or `sprint_id` is added in a later migration). The migration files are ordered to handle this.

---

## RBAC Model

### Org-Level Roles

| Role    | Capabilities |
|---------|-------------|
| owner   | Delete org, transfer ownership, manage members, create/delete projects |
| admin   | Manage members, create/delete projects, update org settings |
| member  | View org and its projects, join projects |

### Project-Level Roles

| Role      | Capabilities |
|-----------|-------------|
| admin     | Update/delete project, manage project members, delete issues, manage stages, start/complete sprints |
| developer | Create issues, assign issues, update issue status/priority/stage, log time, add tags, add relations |
| reporter  | Create issues, comment, view issues |

### RBAC Implementation

- `RequireRole<ProjectRole>` and `RequireRole<OrgRole>` Axum extractors
- Extract `CurrentUser` from JWT middleware
- Query membership for the org/project (from path params)
- Reject if not a member or insufficient role (401/403)
- Org members automatically get `reporter` role in org's projects unless explicitly assigned

---

## Implementation Phases

### Phase 1: Foundation (Axum + DB + Health)

**Dependencies:** `axum`, `tokio`, `sqlx` (postgres, runtime-tokio, tls-rustls, migrate, uuid, chrono), `serde`/`serde_json`, `uuid`, `chrono`

**Tasks:**
1. Extend `Config` with `jwt_secret`, `db_url` parsing, `server_port`
2. Create `AppState` struct holding `PgPool` and `Config`
3. Set up `sqlx::PgPool` with `sqlx::migrate!().run()` on startup
4. Create health endpoints: `GET /api/v1/health/live` and `GET /api/v1/health/ready`
5. Wire up Axum router with `routes()`, shared state, and graceful shutdown via `tokio::signal`
6. Create first migration: `users` table

### Phase 2: Auth (JWT + Register/Login/Refresh)

**Additional dependencies:** `jsonwebtoken`, `argon2`, `validator`

**Tasks:**
1. Create `users` migration (if not done in Phase 1)
2. Create `refresh_tokens` migration
3. Implement `auth::hash` — argon2 password hashing/verification
4. Implement `auth::jwt` — HS256 access + refresh token creation/validation
5. Implement `db::repos::users` — create, get by email, get by id
6. Implement `db::repos::refresh_tokens` — store, find, delete
7. Implement `auth::service` — register, login, refresh logic
8. Implement `auth::handlers` — `POST /api/v1/auth/register`, `/login`, `/refresh`
9. Implement `auth::models` — request/response DTOs with `validator` checks
10. Create `errors.rs` — unified `AppError` enum → `IntoResponse`
11. Create `middleware::auth` — JWT extraction, inject `CurrentUser`
12. Protect routes with auth layer

### Phase 3: RBAC Layer

**Tasks:**
1. Create `organization_memberships` and `project_memberships` migrations
2. Define `OrgRole` and `ProjectRole` as SQL enums + Rust enums
3. Implement `db::repos::memberships` — add/remove/check, get role
4. Create `RequireRole<ProjectRole>` and `RequireRole<OrgRole>` Axum extractors
5. Wire role guards into project/issue routes

### Phase 4: Core Domain (Organizations → Projects → Issues)

**Tasks:**
1. **Organizations** — CRUD at `POST/GET/PATCH/DELETE /api/v1/orgs`
   - Only org owner/admin can update/delete
   - Org creator becomes owner automatically
   - Slug auto-generated from name
2. **Projects** — CRUD at `/api/v1/orgs/{org_slug}/projects`
   - Project membership inherits from org membership
   - Org owner/admin can create projects
   - Project admin can update project settings
3. **Issues** — CRUD at `/api/v1/orgs/{org_slug}/projects/{project_slug}/issues`
   - reporter+ can create issues
   - developer+ can assign/update status
   - admin can delete issues
   - `tsvector` column for full-text search on title + description
   - `GET .../issues?q=search+terms` uses `tsquery`
4. **Pagination** — cursor-based pagination on all list endpoints
5. **utoipa** — add `#[derive(OpenApi)]` annotations, expose `GET /api/v1/docs/openapi.json`

### Phase 5: Issue Rich Content (Tags, Comments, Relations, Time Tracking, Assignees)

**Tasks:**
1. **Tags** — `tags` + `issue_tags` tables
   - Create/list/delete tags per project (developer+ to create, admin to delete)
   - Set issue tags (developer+)
   - Filter issues by tag: `GET .../issues?tag=bug`
2. **Comments** — `comments` table
   - List/create comments on issues (reporter+)
   - Edit own comment, delete own comment or admin
3. **Issue Relations** — `issue_relations` table with relation types
   - Add/remove relations (developer+)
   - Types: blocks, is_blocked_by, duplicates, is_duplicated_by, relates_to, clones, is_cloned_by
4. **Time Tracking** — `time_entries` table
   - Log time on issues (developer+)
   - Delete own entry or admin
   - Aggregate total time spent on issue (computed from entries)
5. **Multiple Assignees** — `issue_assignees` join table
   - Replace single `assignee_id` with join table
   - Set/replace assignees on issue (developer+)
   - Filter issues by assignee: `GET .../issues?assignee={user_id}`

### Phase 6: Sprints & Stages

**Tasks:**
1. **Stages** — `stages` table (custom board columns per project)
   - Create/reorder/delete stages (project admin)
   - Default stages created with new project (e.g. Todo, In Progress, Done)
   - Issue `stage_id` tracks which column it's in
2. **Sprints** — `sprints` table
   - Sprint CRUD endpoints
   - Sprint state transitions: `planned` → `active` → `completed`
   - Issue-sprint assignment via `sprint_id` on issues (developer+)
3. **Sprint Board** — `GET .../sprints/{id}/board`
   - Returns issues grouped by stage within the sprint
   - Moving an issue between stages updates `stage_id`

### Phase 7: Polish & Hardening

**Tasks:**
1. CORS middleware (configurable origins from env)
2. Request ID middleware (propagate through logging)
3. Rate limiting (e.g., `tower-governor`)
4. Comprehensive error responses (validation → 422, auth → 401/403)
5. Integration tests with test DB containers (`testcontainers`)
6. Update Dockerfile and compose.yaml for production-ready build

### Phase 8: Plugin System (Lua Scripting)

**Additional dependencies:** `mlua` (lua54, vendored, async, serialize), `cron` (cron expression parsing)

**Concept:** Users write Lua scripts triggered by events or schedules. Scripts get a sandboxed API to automate workflows (e.g., auto-migrate tasks when a sprint ends, auto-assign issues, send notifications).

**Example user scripts:**
```lua
-- Auto-resolve in-progress tasks when sprint ends
on_event("sprint.ended", function(ctx)
  local issues = ctx.project:issues({ status = "in_progress", sprint = ctx.sprint.id })
  for _, issue in ipairs(issues) do
    issue:update({ status = "resolved", comment = "Auto-resolved: sprint ended" })
  end
end)
```

```lua
-- Every Friday at 6pm, notify about stale issues
on_schedule("0 18 * * 5", function(ctx)
  local stale = ctx.project:issues({ status = "open", updated_before = "7d" })
  for _, issue in ipairs(stale) do
    issue:add_comment("This issue has been inactive for 7 days.")
  end
end)
```

**Trigger models (cron + event-driven only):**

| Trigger | Example | Implementation |
|---------|---------|----------------|
| Event-driven | `on_event("issue.created", ...)` | Hook into service layer, emit events after mutations |
| Scheduled (cron) | `on_schedule("0 18 * * 5", ...)` | Cron expressions, background tokio task |

**Available events:**
- `issue.created`, `issue.updated`, `issue.deleted`
- `issue.status_changed`, `issue.assigned`, `issue.unassigned`
- `comment.created`, `comment.deleted`
- `sprint.started`, `sprint.ended`, `sprint.completed`
- `tag.created`, `tag.removed`

**Sandboxed Lua API surface:**
- `ctx.project:issues(filter)` — query issues
- `ctx.project:sprints()` — list sprints
- `issue:update(fields)` — mutate issue
- `issue:add_comment(body)` — add comment
- `ctx.user` — current user info

**Safety model:**
- No filesystem, no network access
- Execution timeout (e.g., 5s max per script)
- Memory limit via `mlua` Lua state options
- Scripts run in separate tokio tasks, never block the API

**Script storage:**
- `scripts` table in Postgres (org_id, project_id, name, source, trigger_type, trigger_config, enabled)
- `script_revisions` table for revision history / audit
- `script_execution_logs` table for past runs, errors, output

**Codebase location:**
```
src/
├── scripting/
│   ├── mod.rs           # Script engine, mlua setup, sandbox config
│   ├── api.rs           # Lua API bindings (ctx.project, ctx.issue, etc.)
│   ├── scheduler.rs     # Cron-based trigger runner
│   ├── hooks.rs         # Event emission from service layer
│   └── models.rs        # Script DB model + DTOs
```

**Tasks:**
1. Add `scripts`, `script_revisions`, and `script_execution_logs` tables to DB
2. Implement `scripting::mod` — mlua sandbox setup, script compilation/validation
3. Implement `scripting::api` — expose safe Lua API (ctx.project, ctx.issue, ctx.sprint)
4. Implement `scripting::hooks` — event emission from service layer
5. Implement `scripting::scheduler` — cron expression parsing + background tokio task runner
6. Script CRUD endpoints at `/api/v1/orgs/{org_slug}/projects/{project_slug}/scripts`
7. Script execution endpoint: `POST .../scripts/{id}/run` (for manual trigger / testing)
8. Script execution log endpoint: `GET .../scripts/{id}/logs`
9. Admin controls: enable/disable scripts per org/project, execution timeout config

---

## Implementation Order (within each feature)

1. **Migration** → write and run the SQL migration
2. **Repository** → write the sqlx queries + Rust repo struct
3. **Model** → define the Rust domain model + DTOs
4. **Service** → business logic (validation, authorization rules)
5. **Handler** → thin Axum handler calling service
6. **Route** → wire into the router with appropriate middleware
7. **Test** → write a test for the endpoint

---

## Testing Approach

### Phase 1 (Recommended Start)

- Unit tests for pure service logic (no DB, mock repositories)
- Integration tests for repositories with real Postgres via Docker

### Repository Testing

- Define trait interfaces for repositories
- For service unit tests, provide mock implementations
- Focus unit tests on business rules, branching, and error mapping
- Keep SQL correctness in integration tests against real Postgres
- This split gives fast unit tests plus high-confidence DB integration coverage

### Phase 2

- HTTP handler tests with Axum test helpers
- Auth middleware tests
- RBAC extractor tests

### Phase 3

- Minimal end-to-end happy path tests
- Load/stress testing

---

## OpenAPI + Frontend Type Generation

- utoipa annotations on handlers and models
- Auto-generate OpenAPI spec at build time
- Expose at `GET /api/v1/docs/openapi.json`
- Generate frontend TypeScript types from OpenAPI (e.g., `openapi-typescript`)
- Optionally serve Swagger UI from backend via `utoipa-swagger-ui`

---

## Deployment

- Docker Compose for app + postgres
- Healthcheck in compose targets readiness endpoint
- Env-based configuration (`.env`, `.env.example`)
- Multi-stage Dockerfile (rust:alpine builder → alpine runtime)

---

## Iteration Notes

- This file is intentionally a working draft.
- We will refine decisions and turn this into a concrete implementation checklist.
- Originally started as Go/Gin, pivoted to Rust/Axum for the Rust learning journey.