import { Hono } from 'hono';
import { zValidator } from '@hono/zod-validator';
import { asc, eq, sql } from 'drizzle-orm';
import { nanoid } from 'nanoid';
import { z } from 'zod';
import { BUILTIN_POLICIES, ruleInputSchema, type RuleDto } from '@proxy-station/shared';
import { db } from '../db/index.js';
import { policyGroups, rules, rulesets } from '../db/schema.js';
import { seedRulesFromTemplate } from '../db/seed.js';

function loadRules(): RuleDto[] {
  const rows = db.select().from(rules).orderBy(asc(rules.seq)).all();
  const sets = new Map(db.select().from(rulesets).all().map((r) => [r.id, r]));
  return rows.map((r) => {
    const rs = r.value ? sets.get(r.value) : undefined;
    return {
      ...r,
      params: JSON.parse(r.params),
      rulesetName: rs?.name ?? null,
      rulesetUrl: rs?.surgeUrl ?? null,
    };
  });
}

/** 引用不存在的策略组会被 IR 静默剔除，必须在写入前拦下 */
function policyError(policy: string): string | null {
  if ((BUILTIN_POLICIES as readonly string[]).includes(policy)) return null;
  const group = db.select().from(policyGroups).where(eq(policyGroups.name, policy)).get();
  return group?.enabled ? null : `策略「${policy}」不存在或已停用：请选择内置策略或启用的策略组`;
}

function inputError(input: z.output<typeof ruleInputSchema>, id?: string): string | null {
  const err = policyError(input.policy);
  if (err) return err;
  if (input.type === 'FINAL' && db.select().from(rules).all().some((r) => r.type === 'FINAL' && r.id !== id)) return '只能有一条 FINAL 规则';
  if (['RULE-SET', 'DOMAIN-SET'].includes(input.type) && !db.select().from(rulesets).where(eq(rulesets.id, input.value!)).get()) return '规则集不存在';
  return null;
}

export const rulesRoute = new Hono()
  .get('/', (c) => c.json(loadRules()))
  .post('/', zValidator('json', ruleInputSchema), (c) => {
    const input = c.req.valid('json');
    const err = inputError(input);
    if (err) return c.json({ error: err }, 400);
    // 规则首条匹配即生效，自定义规则必须压过模板里的宽泛规则集（如 download.conf），插到最前
    const id = nanoid(10);
    db.transaction(() => {
      if (input.type !== 'FINAL') db.update(rules).set({ seq: sql`${rules.seq} + 1` }).run();
      const seq = input.type === 'FINAL' ? Math.max(-1, ...db.select().from(rules).all().map((r) => r.seq)) + 1 : 0;
      db.insert(rules)
        .values({
          id,
          seq,
          type: input.type,
          value: input.value ?? null,
          policy: input.policy,
          params: JSON.stringify(input.params),
          enabled: input.enabled,
          source: 'custom',
        })
        .run();
    });
    return c.json({ id }, 201);
  })
  .put('/reorder', zValidator('json', z.object({ ids: z.array(z.string()) })), (c) => {
    const { ids } = c.req.valid('json');
    const rows = db.select().from(rules).all();
    const known = new Set(rows.map((r) => r.id));
    if (ids.length !== rows.length || new Set(ids).size !== ids.length || ids.some((id) => !known.has(id))) return c.json({ error: '排序必须包含全部规则且每条仅出现一次' }, 400);
    const finals = rows.filter((r) => r.type === 'FINAL');
    if (finals.length !== 1 || !finals[0].enabled || ids.at(-1) !== finals[0].id) return c.json({ error: '启用的唯一 FINAL 必须位于末尾' }, 400);
    db.transaction(() => ids.forEach((id, i) => db.update(rules).set({ seq: i }).where(eq(rules.id, id)).run()));
    return c.json({ ok: true });
  })
  .post('/reset', (c) => {
    seedRulesFromTemplate(db, { keepCustom: true });
    return c.json({ ok: true, rules: loadRules().length });
  })
  .put('/:id', zValidator('json', ruleInputSchema), (c) => {
    const id = c.req.param('id');
    const existing = db.select().from(rules).where(eq(rules.id, id)).get();
    if (!existing) return c.json({ error: '规则不存在' }, 404);
    const input = c.req.valid('json');
    if (existing.type === 'FINAL' && input.type !== 'FINAL') return c.json({ error: '不能将 FINAL 改成其他规则类型' }, 400);
    if (existing.type !== 'FINAL' && input.type === 'FINAL') return c.json({ error: '请编辑已有 FINAL，不能改变普通规则的类型为 FINAL' }, 400);
    const err = inputError(input, id);
    if (err) return c.json({ error: err }, 400);
    db.update(rules)
      .set({
        type: input.type,
        value: input.value ?? null,
        policy: input.policy,
        params: JSON.stringify(input.params),
        enabled: input.enabled,
      })
      .where(eq(rules.id, id))
      .run();
    return c.json({ ok: true });
  })
  .patch('/:id/enabled', zValidator('json', z.object({ enabled: z.boolean() })), (c) => {
    const row = db.select().from(rules).where(eq(rules.id, c.req.param('id'))).get();
    if (!row) return c.json({ error: '规则不存在' }, 404);
    if (row.type === 'FINAL' && !c.req.valid('json').enabled) return c.json({ error: '不能停用 FINAL' }, 400);
    const res = db
      .update(rules)
      .set({ enabled: c.req.valid('json').enabled })
      .where(eq(rules.id, c.req.param('id')))
      .run();
    if (res.changes === 0) return c.json({ error: '规则不存在' }, 404);
    return c.json({ ok: true });
  })
  .delete('/:id', (c) => {
    const row = db.select().from(rules).where(eq(rules.id, c.req.param('id'))).get();
    if (!row) return c.json({ error: '规则不存在' }, 404);
    if (row.type === 'FINAL') return c.json({ error: '不能删除 FINAL' }, 400);
    const res = db.delete(rules).where(eq(rules.id, c.req.param('id'))).run();
    if (res.changes === 0) return c.json({ error: '规则不存在' }, 404);
    return c.json({ ok: true });
  });

export const rulesetsRoute = new Hono()
  .get('/', (c) => {
    const rows = db.select().from(rulesets).all();
    return c.json(rows);
  })
  .get('/:id/content', async (c) => {
    const rs = db.select().from(rulesets).where(eq(rulesets.id, c.req.param('id'))).get();
    if (!rs) return c.json({ error: '规则集不存在' }, 404);
    const refresh = c.req.query('refresh') === '1';
    try {
      const { fetchRulesetContent } = await import('../services/rulesets/fetch.js');
      const { content, fetchedAt, stale } = await fetchRulesetContent(rs.surgeUrl, { refresh });
      const lineCount = content.split(/\r?\n/).filter((l) => l.trim() && !l.trim().startsWith('#')).length;
      return c.json({ content, fetchedAt, stale, lineCount });
    } catch (e: any) {
      return c.json({ error: `拉取失败：${e.message}` }, 502);
    }
  });