/**
 * channel 存储与传输 adapter —— Drizzle 只准出现在 adapter(编码规范 §5.3)。
 */
import { eq } from 'drizzle-orm';
import { mkdir, writeFile } from 'node:fs/promises';
import { dirname, join } from 'node:path';
import type { Db } from '@shared/db.ts';
import { positionIdSchema } from '@contracts';
import type { AttachmentArchive, ChannelRepository, MailTransport } from '../../port.ts';
import type { ChannelInstanceConfig, ExtractRule, LedgerMapping } from '../domain/payload-mapping.ts';
import { channelTable, outboundMailTable } from './channel-schema.ts';

type Row = typeof channelTable.$inferSelect;

function toConfig(row: Row): ChannelInstanceConfig {
  return {
    id: row.id,
    name: row.name,
    kind: row.kind as ChannelInstanceConfig['kind'],
    address: row.address,
    enabled: row.enabled,
    extract: row.extract as ExtractRule[],
    mapping: row.mapping as LedgerMapping[],
    fallbackPosition: row.fallbackPosition === null ? undefined : positionIdSchema.parse(row.fallbackPosition),
    addressWindowMs: row.addressWindowMs,
  };
}

export function createChannelRepository(db: Db): ChannelRepository {
  return {
    async list() {
      const rows = await db.select().from(channelTable).orderBy(channelTable.name);
      return rows.map(toConfig);
    },
    async get(channelId) {
      const rows = await db.select().from(channelTable).where(eq(channelTable.id, channelId)).limit(1);
      return rows[0] === undefined ? undefined : toConfig(rows[0]);
    },
    async upsert(config) {
      const values = {
        id: config.id,
        name: config.name,
        kind: config.kind,
        address: config.address,
        enabled: config.enabled,
        extract: config.extract,
        mapping: config.mapping,
        fallbackPosition: config.fallbackPosition ?? null,
        addressWindowMs: config.addressWindowMs,
      };
      const [row] = await db
        .insert(channelTable)
        .values(values)
        .onConflictDoUpdate({ target: channelTable.id, set: values })
        .returning();
      if (row === undefined) throw new Error('通道实例写入未返回行');
      return toConfig(row);
    },
  };
}

/**
 * 模拟邮件通道 —— **mock 只允许出现在外界**(README MVP 完成判据):
 * 出站信落库不真发,入站经 /api/ingest 注入。系统内部机制一律真跑。
 */
export function createSimulatedMailTransport(db: Db, ids: { next(): string }): MailTransport {
  return {
    async send(input) {
      const messageId = ids.next();
      const threadId = input.threadId ?? messageId;
      await db.insert(outboundMailTable).values({
        id: messageId,
        threadId,
        fromAddr: input.from,
        toAddrs: [...input.to],
        ccAddrs: [...input.cc],
        subject: input.subject,
        body: input.body,
        attachments: [...input.attachments],
      });
      return { messageId, threadId };
    },
  };
}

/** 原件存档 —— 落本地目录,返回存档地址作为信封的原件指针 */
export function createFileAttachmentArchive(root: string): AttachmentArchive {
  return {
    async put(name, content) {
      const path = join(root, name);
      await mkdir(dirname(path), { recursive: true });
      await writeFile(path, content, 'utf8');
      return `file://${path}`;
    },
  };
}