import { DatabaseSync } from "node:sqlite"
import { mkdirSync } from "node:fs"
import { dirname } from "node:path"

const dbPath = process.env.DB_PATH || "data/app.db"
mkdirSync(dirname(dbPath), { recursive: true })

export const db = new DatabaseSync(dbPath)

// A snapshot of the Slack workspace directory: one row per Slack user that has
// an email, plus a single meta row recording when the snapshot was last swept.
// An unmatched Member is simply one whose email isn't in this table (see ADR-0001).
db.exec(`
  CREATE TABLE IF NOT EXISTS slack_directory (
    email TEXT PRIMARY KEY,
    image_url TEXT,
    slack_id TEXT
  );
  CREATE TABLE IF NOT EXISTS slack_directory_meta (
    id INTEGER PRIMARY KEY CHECK (id = 1),
    refreshed_at INTEGER NOT NULL
  );
`)

export interface DirectoryEntry {
  email: string
  imageUrl: string | null
  slackId: string
}

export function getDirectoryRefreshedAt(): number | null {
  const row = db.prepare("SELECT refreshed_at FROM slack_directory_meta WHERE id = 1").get() as
    | { refreshed_at: number }
    | undefined
  return row ? row.refreshed_at : null
}

// Atomically replace the whole directory snapshot and stamp refreshed_at.
export function replaceDirectory(entries: DirectoryEntry[]): void {
  const insert = db.prepare(
    "INSERT OR REPLACE INTO slack_directory (email, image_url, slack_id) VALUES (?, ?, ?)",
  )
  const stamp = db.prepare(
    "INSERT OR REPLACE INTO slack_directory_meta (id, refreshed_at) VALUES (1, ?)",
  )
  db.exec("BEGIN")
  try {
    db.exec("DELETE FROM slack_directory")
    for (const e of entries) insert.run(e.email.toLowerCase(), e.imageUrl, e.slackId)
    stamp.run(Date.now())
    db.exec("COMMIT")
  } catch (err) {
    db.exec("ROLLBACK")
    throw err
  }
}

export function getDirectoryMap(): Map<string, DirectoryEntry> {
  const rows = db.prepare("SELECT email, image_url, slack_id FROM slack_directory").all() as {
    email: string
    image_url: string | null
    slack_id: string
  }[]
  const map = new Map<string, DirectoryEntry>()
  for (const r of rows) {
    map.set(r.email, { email: r.email, imageUrl: r.image_url, slackId: r.slack_id })
  }
  return map
}