import { and, eq, gte, sql } from 'drizzle-orm'
import { z } from 'zod'

const schema = z.object({
  title: z.string().default(''),
  synopsis: z.string().default(''),
  /** 插入位置；不传则追加到末尾 */
  index: z.number().int().positive().optional()
})

export default defineEventHandler(async (event) => {
  const projectId = param(event)
  getProject(projectId)
  const body = await readJson(event, schema)
  const db = useDb()
  const max = db.select({ m: sql<number>`coalesce(max(${tables.chapters.index}), 0)` }).from(tables.chapters).where(eq(tables.chapters.projectId, projectId)).get()?.m ?? 0
  const index = body.index && body.index <= max ? body.index : max + 1
  const row = db.transaction((tx) => {
    if (index <= max) {
      tx.update(tables.chapters).set({ index: sql`${tables.chapters.index} + 1` })
        .where(and(eq(tables.chapters.projectId, projectId), gte(tables.chapters.index, index))).run()
    }
    return tx.insert(tables.chapters).values({ id: newId(), projectId, index, title: body.title, synopsis: body.synopsis }).returning().get()
  })
  emitProject(projectId, { type: 'chapters' })
  return row
})