'use strict';

const { v4: uuidv4 } = require('uuid');
const { AI_WRITING_STATUS, AI_WRITING_FAILED_STATUS, TEMP_POSITION_BASE } = require('./constants');
const { hasOwn, toInt, normalizeParentId } = require('./helpers');
const { requestFastGptTextWithApp } = require('./ai');
const { reportBusinessCall, resolveContextUserId } = require('../../services/dashboardReporter');
const { ensureInstance, ensureChapter, getInstanceChapterTree } = require('./repository');
const {
   ensureNoChapterCycle,
   reorderChapterSiblingsWithInsert,
   reorderChapterSiblings,
} = require('./ordering');

module.exports.getInstanceChapters = async (ctx, next) => {
   try {
      const instanceId = toInt(ctx.params.instanceId);
      if (!instanceId) throw '缺少参数: instanceId';
      await ensureInstance(ctx, instanceId);
      const chapters = await getInstanceChapterTree(ctx, instanceId);
      ctx.body = chapters;
      ctx.status = 200;
   } catch (error) {
      ctx.logger.log(error);
      ctx.status = 400;
      ctx.body = { message: typeof error === 'string' ? error : '获取章节列表失败' };
   }
};

module.exports.createChapter = async (ctx, next) => {
   const transaction = await ctx.app.fs.dc.orm.transaction();
   try {
      const { models } = ctx.app.fs.dc;
      const instanceId = toInt(ctx.params.instanceId);
      if (!instanceId) throw '缺少参数: instanceId';
      await ensureInstance(ctx, instanceId, transaction);
      const { title, position, prompts } = ctx.request.body || {};
      if (!String(title || '').trim()) throw '缺少参数: title';
      const parentId = normalizeParentId(ctx.request.body?.parentId);
      await ensureNoChapterCycle(ctx, instanceId, null, parentId, transaction);
      const created = await models.ReportChapter.create({
         instanceId,
         parentId,
         title: String(title).trim(),
         position: TEMP_POSITION_BASE - 1,
         prompts: prompts || null,
         status: null,
      }, {
         transaction,
         returning: true,
      });
      await reorderChapterSiblingsWithInsert(ctx, instanceId, parentId, created.id, position, transaction);
      const fresh = await models.ReportChapter.findByPk(created.id, { transaction });
      await transaction.commit();
      ctx.body = fresh;
      ctx.status = 200;
   } catch (error) {
      await transaction.rollback();
      ctx.logger.log(error);
      ctx.status = 400;
      ctx.body = { message: typeof error === 'string' ? error : '创建章节失败' };
   }
};

module.exports.updateChapter = async (ctx, next) => {
   const transaction = await ctx.app.fs.dc.orm.transaction();
   try {
      const { models } = ctx.app.fs.dc;
      const instanceId = toInt(ctx.params.instanceId);
      const chapterId = toInt(ctx.params.chapterId);
      if (!instanceId || !chapterId) throw '缺少参数';
      const chapter = await ensureChapter(ctx, instanceId, chapterId, transaction);
      const body = ctx.request.body || {};
      const updateData = {};
      if (hasOwn(body, 'title')) updateData.title = body.title ? String(body.title).trim() : '';
      if (hasOwn(body, 'prompts')) updateData.prompts = body.prompts || null;
      if (hasOwn(body, 'status')) updateData.status = body.status || null;
      const hasContentField = hasOwn(body, 'content');
      const nextContent = hasContentField ? String(body.content || '') : null;

      const oldParentId = chapter.parentId;
      const nextParentId = hasOwn(body, 'parentId') ? normalizeParentId(body.parentId) : chapter.parentId;
      await ensureNoChapterCycle(ctx, instanceId, chapterId, nextParentId, transaction);

      const needMove = hasOwn(body, 'parentId') || hasOwn(body, 'position');
      if (!needMove) {
         await models.ReportChapter.update(updateData, { where: { id: chapterId }, transaction });
         if (hasContentField) {
            const chapterBlocks = await models.ReportBlock.findAll({
               where: { instanceId, chapterId },
               order: [['position', 'ASC'], ['id', 'ASC']],
               raw: true,
               transaction,
            });
            const textBlock = chapterBlocks.find(
               (block) => String(block?.blockType || '').trim() === 'text'
            );
            if (textBlock?.id) {
               await models.ReportBlock.update({
                  contentSnapshot: {
                     ...(textBlock?.contentSnapshot || {}),
                     content: nextContent,
                  },
                  updatedAt: new Date(),
               }, {
                  where: { id: textBlock.id, instanceId },
                  transaction,
               });
            } else {
               const nextPosition = chapterBlocks.reduce((max, item) => {
                  const pos = Number(item?.position || 0);
                  return pos > max ? pos : max;
               }, 0) + 1;
               await models.ReportBlock.create({
                  instanceId,
                  chapterId,
                  blockType: 'text',
                  position: nextPosition,
                  config: {
                     title: '正文',
                  },
                  contentSnapshot: {
                     content: nextContent,
                  },
                  updatedAt: new Date(),
               }, {
                  transaction,
               });
            }
         }
         await transaction.commit();
         ctx.status = 204;
         return;
      }

      updateData.parentId = nextParentId;
      updateData.position = TEMP_POSITION_BASE - 1;
      await models.ReportChapter.update(updateData, { where: { id: chapterId }, transaction });

      if (oldParentId !== nextParentId) {
         await reorderChapterSiblings(ctx, instanceId, oldParentId, transaction);
      }

      const targetPosition = hasOwn(body, 'position')
         ? body.position
         : (oldParentId === nextParentId ? chapter.position : undefined);
      await reorderChapterSiblingsWithInsert(ctx, instanceId, nextParentId, chapterId, targetPosition, transaction);

      await transaction.commit();
      ctx.status = 204;
   } catch (error) {
      await transaction.rollback();
      ctx.logger.log(error);
      ctx.status = 400;
      ctx.body = { message: typeof error === 'string' ? error : '更新章节失败' };
   }
};

module.exports.deleteChapter = async (ctx, next) => {
   const transaction = await ctx.app.fs.dc.orm.transaction();
   try {
      const { models } = ctx.app.fs.dc;
      const instanceId = toInt(ctx.params.instanceId);
      const chapterId = toInt(ctx.params.chapterId);
      if (!instanceId || !chapterId) throw '缺少参数';
      const chapter = await ensureChapter(ctx, instanceId, chapterId, transaction);
      await models.ReportChapter.destroy({
         where: { id: chapterId, instanceId },
         transaction,
      });
      await reorderChapterSiblings(ctx, instanceId, chapter.parentId, transaction);
      await transaction.commit();
      ctx.status = 204;
   } catch (error) {
      await transaction.rollback();
      ctx.logger.log(error);
      ctx.status = 400;
      ctx.body = { message: typeof error === 'string' ? error : '删除章节失败' };
   }
};

module.exports.generateChapterAiContent = async (ctx, next) => {
   try {
      const { models } = ctx.app.fs.dc;
      const instanceId = toInt(ctx.params.instanceId);
      const chapterId = toInt(ctx.params.chapterId);
      const { prompt, blockType, config } = ctx.request.body || {};
      if (!instanceId || !chapterId) throw '缺少参数';
      const promptText = String(prompt || '').trim();
      if (!promptText) throw '缺少参数: prompt';
      const chapter = await ensureChapter(ctx, instanceId, chapterId);
      await models.ReportChapter.update({
         prompts: promptText,
         status: AI_WRITING_STATUS,
      }, {
         where: { id: chapterId, instanceId },
      });

      ctx.body = {
         instanceId,
         chapterId,
         status: AI_WRITING_STATUS,
         message: 'AI 写作任务已开始',
      };
      ctx.status = 202;

      const app = ctx.app;
      const logger = ctx.logger;
      const analyticsUserId = resolveContextUserId(ctx);
      const actionId = `report-chapter:${instanceId}:${chapterId}:${uuidv4()}`;
      const finalBlockType = String(blockType || 'ai_analysis');
      const finalConfig = config || {};

      setImmediate(async () => {
         const transaction = await app.fs.dc.orm.transaction();
         try {
            const curReport = await app.fs.dc.models.ReportInstance.findByPk(instanceId, { transaction });
            const chapters = await getInstanceChapterTree(ctx, instanceId, transaction);
            const aiText = await requestFastGptTextWithApp(
               ctx,
               `章节标题: ${chapter.title}\n写作提示: ${promptText}`,
               {
                  actionId,
                  userId: analyticsUserId,
                  variables: {
                     type: '章节内容生成',
                     reportTitle: curReport.name,
                     // chapters,
                  }
               }
            );
            await app.fs.dc.models.ReportBlock.destroy({
               where: { instanceId, chapterId },
               transaction,
            });
            await app.fs.dc.models.ReportBlock.create({
               instanceId,
               chapterId,
               blockType: finalBlockType,
               position: 1,
               config: finalConfig,
               contentSnapshot: {
                  content: aiText,
               },
               updatedAt: new Date(),
            }, { transaction });
            await app.fs.dc.models.ReportChapter.update({
               status: null,
            }, {
               where: { id: chapterId, instanceId },
               transaction,
            });
            await transaction.commit();
            await reportBusinessCall({
               ctx,
               applicationId: 'exp-report',
               eventId: actionId,
               traceId: actionId,
               userId: analyticsUserId,
               reportContext: { action: 'chapter_generation', instanceId, chapterId },
            });
         } catch (error) {
            await transaction.rollback();
            logger.log(error);
            await app.fs.dc.models.ReportChapter.update({
               status: AI_WRITING_FAILED_STATUS,
            }, {
               where: { id: chapterId, instanceId },
            });
         }
      });
   } catch (error) {
      ctx.logger.log(error);
      ctx.status = 400;
      ctx.body = { message: typeof error === 'string' ? error : '触发章节 AI 写作失败' };
   }
};