feat(db): SQLite module + initial migration (Task #1)

src/lib/db.ts

@@ -0,0 +1,99 @@
+import { Database } from "bun:sqlite"
+import fs from "node:fs"
+import path from "node:path"
+
+import migration001 from "./migrations/001_initial.sql" with { type: "text" }
+
+export const CURRENT_SCHEMA_VERSION = 1
+
+const MIGRATIONS: Array<{ version: number; sql: string }> = [
+  { version: 1, sql: migration001 },
+]
+
+let dbInstance: Database | undefined
+
+export function initDb(dbPath: string): Database {
+  if (dbInstance) return dbInstance
+
+  if (dbPath !== ":memory:") {
+    fs.mkdirSync(path.dirname(dbPath), { recursive: true })
+  }
+
+  const db = new Database(dbPath, { create: true })
+
+  // Pragmas — set before any schema work.
+  db.run("PRAGMA journal_mode = WAL")
+  db.run("PRAGMA synchronous = NORMAL")
+  db.run("PRAGMA foreign_keys = ON")
+
+  runMigrations(db)
+
+  dbInstance = db
+  return db
+}
+
+export function getDb(): Database {
+  if (!dbInstance) {
+    throw new Error(
+      "Database not initialized. Call initDb(path) before getDb().",
+    )
+  }
+  return dbInstance
+}
+
+export function withTransaction<T>(fn: (db: Database) => T): T {
+  const db = getDb()
+  const tx = db.transaction((arg: () => T) => arg())
+  return tx(() => fn(db))
+}
+
+/**
+ * Test-only helper. Closes any current instance and clears the singleton so
+ * the next initDb call starts from scratch. Production code must never call
+ * this — it exists to keep tests isolated.
+ */
+export function __resetDbForTests(): void {
+  if (dbInstance) {
+    try {
+      dbInstance.close()
+    } catch {
+      // ignore
+    }
+    dbInstance = undefined
+  }
+}
+
+function runMigrations(db: Database): void {
+  // Bootstrap meta table so we can read schema_version.
+  db.run(
+    "CREATE TABLE IF NOT EXISTS meta (key TEXT PRIMARY KEY, value TEXT NOT NULL)",
+  )
+
+  const row = db
+    .query<
+      { value: string },
+      []
+    >("SELECT value FROM meta WHERE key='schema_version'")
+    .get()
+  const currentVersion = row ? Number.parseInt(row.value, 10) : 0
+
+  const pending = MIGRATIONS.filter((m) => m.version > currentVersion).sort(
+    (a, b) => a.version - b.version,
+  )
+
+  if (pending.length === 0) return
+
+  const apply = db.transaction(() => {
+    for (const m of pending) {
+      // Migration SQL contains multiple statements; only exec() handles that.
+      // eslint-disable-next-line @typescript-eslint/no-deprecated
+      db.exec(m.sql)
+    }
+    db.run(
+      "INSERT INTO meta (key, value) VALUES ('schema_version', ?) "
+        + "ON CONFLICT(key) DO UPDATE SET value=excluded.value",
+      [String(CURRENT_SCHEMA_VERSION)],
+    )
+  })
+  apply()
+}

src/lib/migrations/001_initial.sql

@@ -0,0 +1,113 @@
+-- Initial schema for copilot-api multi-account & usage billing.
+-- Owned by tasks #1 (this migration), #2 (accounts loader), #6 (usage recorder),
+-- #13 (pricing version writer). See docs/design/.
+
+CREATE TABLE IF NOT EXISTS accounts (
+  name TEXT PRIMARY KEY,
+  account_type TEXT NOT NULL,
+  created_at INTEGER NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS model_pricing (
+  model_id TEXT PRIMARY KEY,
+  input_per_mtok REAL,
+  cached_input_per_mtok REAL,
+  output_per_mtok REAL,
+  reasoning_per_mtok REAL,
+  premium_multiplier REAL,
+  premium_unit_price REAL,
+  currency TEXT NOT NULL DEFAULT 'USD',
+  source TEXT,
+  source_skus TEXT,
+  updated_at INTEGER NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS pricing_sync_log (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  ts INTEGER NOT NULL,
+  status TEXT NOT NULL,
+  source_count INTEGER,
+  llm_model TEXT,
+  models_updated INTEGER,
+  models_rejected INTEGER,
+  error TEXT,
+  raw_request_json TEXT,
+  raw_response_json TEXT,
+  diff_json TEXT
+);
+
+CREATE TABLE IF NOT EXISTS model_pricing_versions (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  model_id TEXT NOT NULL,
+  effective_from INTEGER NOT NULL,
+  effective_to INTEGER,
+  input_per_mtok REAL,
+  cached_input_per_mtok REAL,
+  output_per_mtok REAL,
+  reasoning_per_mtok REAL,
+  premium_multiplier REAL,
+  premium_unit_price REAL,
+  currency TEXT NOT NULL DEFAULT 'USD',
+  source TEXT,
+  source_skus TEXT,
+  sync_log_id INTEGER,
+  created_at INTEGER NOT NULL,
+  FOREIGN KEY (sync_log_id) REFERENCES pricing_sync_log(id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_pricing_versions_model_time
+  ON model_pricing_versions(model_id, effective_from);
+
+CREATE INDEX IF NOT EXISTS idx_pricing_versions_current
+  ON model_pricing_versions(model_id) WHERE effective_to IS NULL;
+
+CREATE TABLE IF NOT EXISTS usage_events (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  ts INTEGER NOT NULL,
+  account_name TEXT NOT NULL,
+  model_id TEXT NOT NULL,
+  endpoint TEXT NOT NULL,
+  upstream_format TEXT NOT NULL,
+  is_streaming INTEGER NOT NULL,
+  input_tokens INTEGER DEFAULT 0,
+  cached_input_tokens INTEGER DEFAULT 0,
+  output_tokens INTEGER DEFAULT 0,
+  reasoning_tokens INTEGER DEFAULT 0,
+  total_tokens INTEGER DEFAULT 0,
+  premium_request_count REAL DEFAULT 0,
+  input_price_snapshot REAL,
+  cached_input_price_snapshot REAL,
+  output_price_snapshot REAL,
+  reasoning_price_snapshot REAL,
+  premium_unit_price_snapshot REAL,
+  premium_multiplier_snapshot REAL,
+  request_id TEXT,
+  status TEXT NOT NULL,
+  duration_ms INTEGER,
+  FOREIGN KEY (account_name) REFERENCES accounts(name)
+);
+
+CREATE INDEX IF NOT EXISTS idx_usage_account_model_ts
+  ON usage_events(account_name, model_id, ts);
+
+CREATE INDEX IF NOT EXISTS idx_usage_ts ON usage_events(ts);
+
+CREATE TABLE IF NOT EXISTS usage_daily (
+  day TEXT NOT NULL,
+  account_name TEXT NOT NULL,
+  model_id TEXT NOT NULL,
+  endpoint TEXT NOT NULL,
+  req_count INTEGER NOT NULL DEFAULT 0,
+  input_tokens INTEGER NOT NULL DEFAULT 0,
+  cached_input_tokens INTEGER NOT NULL DEFAULT 0,
+  output_tokens INTEGER NOT NULL DEFAULT 0,
+  reasoning_tokens INTEGER NOT NULL DEFAULT 0,
+  total_tokens INTEGER NOT NULL DEFAULT 0,
+  premium_requests REAL NOT NULL DEFAULT 0,
+  PRIMARY KEY (day, account_name, model_id, endpoint)
+);
+
+CREATE TABLE IF NOT EXISTS meta (
+  key TEXT PRIMARY KEY,
+  value TEXT NOT NULL
+);

src/lib/paths.ts

@@ -5,10 +5,12 @@ import path from "node:path"
 const APP_DIR = path.join(os.homedir(), ".local", "share", "copilot-api")
 
 const GITHUB_TOKEN_PATH = path.join(APP_DIR, "github_token")
+const USAGE_DB_PATH = path.join(APP_DIR, "usage.sqlite")
 
 export const PATHS = {
   APP_DIR,
   GITHUB_TOKEN_PATH,
+  USAGE_DB_PATH,
 }
 
 export async function ensurePaths(): Promise<void> {

src/start.ts

@@ -6,7 +6,8 @@ import consola from "consola"
 import { serve, type ServerHandler } from "srvx"
 import invariant from "tiny-invariant"
 
-import { ensurePaths } from "./lib/paths"
+import { initDb } from "./lib/db"
+import { ensurePaths, PATHS } from "./lib/paths"
 import { initProxyFromEnv } from "./lib/proxy"
 import { generateEnvScript } from "./lib/shell"
 import { state } from "./lib/state"
@@ -25,6 +26,7 @@ interface RunServerOptions {
   claudeCode: boolean
   showToken: boolean
   proxyEnv: boolean
+  dbPath: string
 }
 
 export async function runServer(options: RunServerOptions): Promise<void> {
@@ -48,6 +50,7 @@ export async function runServer(options: RunServerOptions): Promise<void> {
   state.showToken = options.showToken
 
   await ensurePaths()
+  initDb(options.dbPath)
   await cacheVSCodeVersion()
 
   if (options.githubToken) {
@@ -184,6 +187,12 @@ export const start = defineCommand({
       default: false,
       description: "Initialize proxy from environment variables",
     },
+    "db-path": {
+      type: "string",
+      default: PATHS.USAGE_DB_PATH,
+      description:
+        "Path to the usage SQLite database (defaults to ~/.local/share/copilot-api/usage.sqlite)",
+    },
   },
   run({ args }) {
     const rateLimitRaw = args["rate-limit"]
@@ -202,6 +211,7 @@ export const start = defineCommand({
       claudeCode: args["claude-code"],
       showToken: args["show-token"],
       proxyEnv: args["proxy-env"],
+      dbPath: args["db-path"],
     })
   },
 })

src/types.d.ts

@@ -0,0 +1,4 @@
+declare module "*.sql" {
+  const content: string
+  export default content
+}