import {
  BadRequestException,
  ForbiddenException,
  Injectable,
  NotFoundException,
} from '@nestjs/common';
import {
  LLM_PROVIDERS,
  LLM_PROVIDER_PRESETS,
  type CreateLlmApiConfigRequest,
  type LlmApiConfigDto,
  type LlmApiConfigOptionDto,
  type LlmProvider,
  type UpdateLlmApiConfigRequest,
} from '@dukang/shared-types';
import { PrismaService } from '../../common/prisma/prisma.module';
import { serializeBigInt } from '../../common/decorators/current-user.decorator';
import { LlmChatClient, normalizeLlmBaseUrl } from '../../integrations/llm/llm-chat.client';

type ActorCtx = { actorId: bigint; isSuperAdmin: boolean };

function isProvider(v: string): v is LlmProvider {
  return (LLM_PROVIDERS as readonly string[]).includes(v);
}

@Injectable()
export class AdminLlmConfigsService {
  constructor(
    private readonly prisma: PrismaService,
    private readonly llm: LlmChatClient,
  ) {}

  async resolveActor(actorId: bigint): Promise<ActorCtx> {
    const account = await this.prisma.hqAccount.findUnique({
      where: { id: actorId },
      select: { adminRole: true, status: true },
    });
    if (!account || account.status !== 'ACTIVE') {
      throw new ForbiddenException('账号不可用');
    }
    return {
      actorId,
      isSuperAdmin: account.adminRole === 'SUPER_ADMIN',
    };
  }

  async list(
    actor: ActorCtx,
    query: { name?: string; enabled?: string; page?: number; pageSize?: number },
  ) {
    const page = query.page ?? 1;
    const pageSize = query.pageSize ?? 20;
    const where: {
      name?: { contains: string };
      enabled?: boolean;
      createdByHqAccountId?: bigint;
    } = {};
    if (!actor.isSuperAdmin) where.createdByHqAccountId = actor.actorId;
    if (query.name?.trim()) where.name = { contains: query.name.trim() };
    if (query.enabled === 'true' || query.enabled === 'false') {
      where.enabled = query.enabled === 'true';
    }

    const [items, total] = await Promise.all([
      this.prisma.llmApiConfig.findMany({
        where,
        orderBy: [{ id: 'desc' }],
        skip: (page - 1) * pageSize,
        take: pageSize,
      }),
      this.prisma.llmApiConfig.count({ where }),
    ]);

    const ownerIds = [...new Set(items.map((i) => i.createdByHqAccountId))];
    const owners = ownerIds.length
      ? await this.prisma.hqAccount.findMany({
          where: { id: { in: ownerIds } },
          select: { id: true, name: true },
        })
      : [];
    const ownerMap = new Map(owners.map((o) => [o.id.toString(), o.name]));

    return serializeBigInt({
      items: items.map((row) => this.toDto(row, actor, ownerMap.get(row.createdByHqAccountId.toString()) ?? null)),
      total,
      page,
      pageSize,
    });
  }

  /** 企微绑定下拉：已启用；非超管仅自己的 */
  async options(actor: ActorCtx): Promise<LlmApiConfigOptionDto[]> {
    const where: { enabled: boolean; createdByHqAccountId?: bigint } = { enabled: true };
    if (!actor.isSuperAdmin) where.createdByHqAccountId = actor.actorId;
    const rows = await this.prisma.llmApiConfig.findMany({
      where,
      orderBy: [{ id: 'desc' }],
      select: { id: true, name: true, provider: true, modelName: true, enabled: true },
    });
    return rows.map((r) => ({
      id: r.id.toString(),
      name: r.name,
      provider: (isProvider(r.provider) ? r.provider : 'CUSTOM') as LlmProvider,
      modelName: r.modelName,
      enabled: r.enabled,
    }));
  }

  async detail(actor: ActorCtx, id: bigint) {
    const row = await this.requireReadable(actor, id);
    const owner = await this.prisma.hqAccount.findUnique({
      where: { id: row.createdByHqAccountId },
      select: { name: true },
    });
    return this.toDto(row, actor, owner?.name ?? null);
  }

  async create(actor: ActorCtx, dto: CreateLlmApiConfigRequest) {
    const name = dto.name?.trim();
    if (!name) throw new BadRequestException('请填写名称');
    if (!isProvider(dto.provider)) throw new BadRequestException('无效提供商');
    const apiKey = dto.apiKey?.trim();
    if (!apiKey) throw new BadRequestException('请填写 API Key');

    const preset = LLM_PROVIDER_PRESETS[dto.provider];
    const baseUrl = normalizeLlmBaseUrl(dto.baseUrl?.trim() || preset.defaultBaseUrl);
    const modelName = dto.modelName?.trim() || preset.defaultModel;
    if (!baseUrl) throw new BadRequestException('请填写 Base URL');
    if (!modelName) throw new BadRequestException('请填写模型名');

    const row = await this.prisma.llmApiConfig.create({
      data: {
        name,
        provider: dto.provider,
        baseUrl,
        apiKey,
        modelName,
        temperature: dto.temperature ?? null,
        maxTokens: dto.maxTokens ?? null,
        systemPrompt: dto.systemPrompt?.trim() || null,
        enabled: dto.enabled !== false,
        createdByHqAccountId: actor.actorId,
      },
    });
    return this.toDto(row, actor, null);
  }

  async update(actor: ActorCtx, id: bigint, dto: UpdateLlmApiConfigRequest) {
    const row = await this.requireReadable(actor, id);
    const isOwner = row.createdByHqAccountId === actor.actorId;

    if (!actor.isSuperAdmin) {
      if (!isOwner) throw new ForbiddenException('只能操作自己创建的配置');
      // 非超管仅可改 enabled
      const keys = Object.keys(dto).filter((k) => (dto as Record<string, unknown>)[k] !== undefined);
      if (keys.some((k) => k !== 'enabled')) {
        throw new ForbiddenException('非超级管理员只能修改配置是否生效');
      }
      if (dto.enabled === undefined) throw new BadRequestException('请指定 enabled');
      const updated = await this.prisma.llmApiConfig.update({
        where: { id },
        data: { enabled: dto.enabled },
      });
      return this.toDto(updated, actor, null);
    }

    // 超管全量
    let provider = row.provider as LlmProvider;
    if (dto.provider !== undefined) {
      if (!isProvider(dto.provider)) throw new BadRequestException('无效提供商');
      provider = dto.provider;
    }
    const preset = LLM_PROVIDER_PRESETS[provider];
    const data: {
      name?: string;
      provider?: string;
      baseUrl?: string;
      apiKey?: string;
      modelName?: string;
      temperature?: number | null;
      maxTokens?: number | null;
      systemPrompt?: string | null;
      enabled?: boolean;
    } = {};
    if (dto.name !== undefined) {
      const name = dto.name.trim();
      if (!name) throw new BadRequestException('名称不能为空');
      data.name = name;
    }
    if (dto.provider !== undefined) data.provider = provider;
    if (dto.baseUrl !== undefined) {
      data.baseUrl = normalizeLlmBaseUrl(dto.baseUrl.trim() || preset.defaultBaseUrl);
      if (!data.baseUrl) throw new BadRequestException('Base URL 不能为空');
    }
    if (dto.apiKey !== undefined && dto.apiKey.trim()) data.apiKey = dto.apiKey.trim();
    if (dto.modelName !== undefined) {
      data.modelName = dto.modelName.trim() || preset.defaultModel;
      if (!data.modelName) throw new BadRequestException('模型名不能为空');
    }
    if (dto.temperature !== undefined) data.temperature = dto.temperature;
    if (dto.maxTokens !== undefined) data.maxTokens = dto.maxTokens;
    if (dto.systemPrompt !== undefined) data.systemPrompt = dto.systemPrompt?.trim() || null;
    if (dto.enabled !== undefined) data.enabled = dto.enabled;

    const updated = await this.prisma.llmApiConfig.update({ where: { id }, data });
    return this.toDto(updated, actor, null);
  }

  async remove(actor: ActorCtx, id: bigint) {
    if (!actor.isSuperAdmin) {
      throw new ForbiddenException('仅超级管理员可删除语言模型配置');
    }
    const row = await this.prisma.llmApiConfig.findUnique({ where: { id } });
    if (!row) throw new NotFoundException('配置不存在');
    await this.prisma.llmApiConfig.delete({ where: { id } });
    return { ok: true };
  }

  async test(actor: ActorCtx, id: bigint) {
    const row = await this.requireReadable(actor, id);
    if (!row.enabled) throw new BadRequestException('配置未启用');
    const reply = await this.llm.chat({
      baseUrl: row.baseUrl,
      apiKey: row.apiKey,
      model: row.modelName,
      temperature: row.temperature != null ? Number(row.temperature) : 0.2,
      maxTokens: row.maxTokens ?? 64,
      messages: [
        { role: 'system', content: '用一句话回复：连接成功。' },
        { role: 'user', content: 'ping' },
      ],
    });
    return { ok: true, reply };
  }

  private async requireReadable(actor: ActorCtx, id: bigint) {
    const row = await this.prisma.llmApiConfig.findUnique({ where: { id } });
    if (!row) throw new NotFoundException('配置不存在');
    if (!actor.isSuperAdmin && row.createdByHqAccountId !== actor.actorId) {
      throw new ForbiddenException('无权查看该配置');
    }
    return row;
  }

  private toDto(
    row: {
      id: bigint;
      name: string;
      provider: string;
      baseUrl: string;
      apiKey: string;
      modelName: string;
      temperature: { toNumber?: () => number } | number | null;
      maxTokens: number | null;
      systemPrompt: string | null;
      enabled: boolean;
      createdByHqAccountId: bigint;
      createdAt: Date;
      updatedAt: Date;
    },
    actor: ActorCtx,
    createdByName: string | null,
  ): LlmApiConfigDto {
    const isOwner = row.createdByHqAccountId === actor.actorId;
    const temp =
      row.temperature == null
        ? null
        : typeof row.temperature === 'number'
          ? row.temperature
          : Number(row.temperature);
    return {
      id: row.id.toString(),
      name: row.name,
      provider: (isProvider(row.provider) ? row.provider : 'CUSTOM') as LlmProvider,
      baseUrl: row.baseUrl,
      modelName: row.modelName,
      apiKeyConfigured: !!row.apiKey,
      temperature: temp,
      maxTokens: row.maxTokens,
      systemPrompt: row.systemPrompt,
      enabled: row.enabled,
      createdByHqAccountId: row.createdByHqAccountId.toString(),
      createdByName,
      isOwner,
      canEditFull: actor.isSuperAdmin,
      createdAt: row.createdAt.toISOString(),
      updatedAt: row.updatedAt.toISOString(),
    };
  }
}