import { randomUUID } from 'crypto'
import type { Snapshot, SnapshotType } from '../../../shared/types'
import type { SqliteDb } from '../types'

function mapRow(row: Record<string, unknown>): Snapshot {
  return {
    id: row.id as string,
    chapterId: row.chapter_id as string,
    type: row.type as SnapshotType,
    name: (row.name as string) ?? '',
    content: row.content as string,
    createdAt: row.created_at as string
  }
}

export class SnapshotRepository {
  constructor(private db: SqliteDb) {}

  create(chapterId: string, type: SnapshotType, content: string, name = ''): Snapshot {
    const id = randomUUID()
    this.db
      .prepare(`INSERT INTO snapshots (id, chapter_id, type, name, content) VALUES (?, ?, ?, ?, ?)`)
      .run(id, chapterId, type, name, content)
    return this.get(id)!
  }

  get(id: string): Snapshot | null {
    const row = this.db.prepare('SELECT * FROM snapshots WHERE id = ?').get(id) as
      | Record<string, unknown>
      | undefined
    return row ? mapRow(row) : null
  }

  list(chapterId: string): Snapshot[] {
    return (
      this.db
        .prepare('SELECT * FROM snapshots WHERE chapter_id = ? ORDER BY created_at DESC')
        .all(chapterId) as Record<string, unknown>[]
    ).map(mapRow)
  }

  delete(id: string): void {
    this.db.prepare('DELETE FROM snapshots WHERE id = ?').run(id)
  }

  pruneAuto(chapterId: string, max: number): void {
    const autos = (
      this.db
        .prepare(
          `SELECT id FROM snapshots WHERE chapter_id = ? AND type = 'auto' ORDER BY created_at ASC`
        )
        .all(chapterId) as { id: string }[]
    )
    const excess = autos.length - max
    if (excess <= 0) return
    for (let i = 0; i < excess; i++) {
      this.delete(autos[i].id)
    }
  }

  prunePersist(chapterId: string, max: number): void {
    const items = (
      this.db
        .prepare(
          `SELECT id FROM snapshots WHERE chapter_id = ? AND type = 'persist' ORDER BY created_at ASC`
        )
        .all(chapterId) as { id: string }[]
    )
    const excess = items.length - max
    if (excess <= 0) return
    for (let i = 0; i < excess; i++) {
      this.delete(items[i].id)
    }
  }

  restore(snapshotId: string): string {
    const snap = this.get(snapshotId)
    if (!snap) throw new Error('Snapshot not found')
    return snap.content
  }
}