import { v4 as uuid } from 'uuid';
import { eq, isNull, sql, inArray } from 'drizzle-orm';
import { db } from '../db/index';
import {
  gitCommits, aiAnalyzedCommits, projectRepos, projects,
  objectives, keyResults, krLogs, syncLogs, users,
} from '../db/schema';
import { callLLM, parseLLMJson } from './llm-client';
import { dateToPeriod, recalcObjectiveProgress } from './okr';
import dayjs from 'dayjs';

// ── Types ──

interface AIAction {
  type: 'create_objective' | 'create_kr' | 'update_progress' | 'complete_kr';
  ownerId?: string;
  objectiveId?: string;
  krId?: string;
  title?: string;
  sourceKey?: string;
  currentValue?: number;
  newCurrentValue?: number;
  startDate?: string;
  endDate?: string;
  reasoning?: string;
  keyResults?: {
    title: string;
    sourceKey: string;
    currentValue: number;
    startDate?: string;
    endDate?: string;
  }[];
}

interface AIResponse {
  actions: AIAction[];
  summary: string;
}

interface CommitGroup {
  repoName: string;
  projectId: string;
  projectName: string;
  commits: {
    sha: string;
    authorName: string | null;
    userId: string | null;
    message: string | null;
    additions: number;
    deletions: number;
    committedAt: Date;
  }[];
}

// ── System Prompt ──

const SYSTEM_PROMPT = `你是一个开发团队的 OKR 管理助手。你的任务是分析 git commit 记录，管理项目的 OKR（目标与关键成果）。

你需要分析提交记录，输出 JSON 格式的操作指令：

判断逻辑：
- commit 包含 "完成"、"done"、"finished"、"实现完毕" 等完成语义 → 对应 KR 标记完成
- commit 是 feat/feature 类型但未完成 → 更新对应 KR 进度（根据描述估算百分比）
- commit 涉及的功能在现有 KR 中��存在 → 创建新 KR（需同时提供时间节点）
- fix/refactor/chore/docs 类 commit → 只在涉及明确功能时才操作
- 不要为同一个功能创建重复的 KR，已有相同 sourceKey 的直接更新

新建 Objective 规则：
- 如果提交涉及的功能没有归属到任何已有 Objective → 可以创建新 Objective
- Objective 的 startDate 和 endDate 由你根据提交内容和功能复杂度判断
- period 格式为 "YYYY-Qn"（如 "2026-Q2"），根据 endDate 推算

新建 KR 规则：
- targetValue = 100, unit = "%"
- 根据 commit 语义估算 currentValue（初步实现=30, 基本完成=70, 完成=100）
- sourceKey 用小写英文短横线格式（如 "user-login", "payment-module"）
- title 用中文描述
- startDate 和 endDate 由你根据功能复杂度和提交时间判断

每个 action 中的 ownerId 必须是提交人的 userId，表示该 OKR 归谁负责。`;

// ── Core Functions ──

/**
 * 获取未分析的 commits，按 repoName 分组
 */
async function gatherUnanalyzedCommits(): Promise<CommitGroup[]> {
  // 获取所有已分析的 SHA
  const analyzed = await db.select({ sha: aiAnalyzedCommits.commitSha }).from(aiAnalyzedCommits);
  const analyzedSet = new Set(analyzed.map(a => a.sha));

  // 获取所有 commits（有 userId 的，且 4 月份及之后的）
  const cutoffDate = new Date('2026-01-01T00:00:00');
  const allCommits = await db.select().from(gitCommits);
  const unanalyzed = allCommits.filter(c =>
    c.userId && !analyzedSet.has(c.sha) && new Date(c.committedAt) >= cutoffDate
  );

  if (unanalyzed.length === 0) return [];

  // 获取 projectRepos 映射 repoName → projectId
  const bindings = await db.select().from(projectRepos);
  const repoToProject = new Map<string, string>();
  for (const b of bindings) {
    // 支持多种格式的 repoName 匹配
    const name = extractRepoName(b.repoName);
    repoToProject.set(name, b.projectId);
  }

  // 获取 projects 名称
  const allProjects = await db.select().from(projects);
  const projectMap = new Map(allProjects.map(p => [p.id, p.name]));

  // 按 repoName 分组
  const groups = new Map<string, CommitGroup>();
  for (const commit of unanalyzed) {
    const projectId = repoToProject.get(commit.repoName);
    if (!projectId) continue; // 仓库未绑定项目，跳过

    if (!groups.has(commit.repoName)) {
      groups.set(commit.repoName, {
        repoName: commit.repoName,
        projectId,
        projectName: projectMap.get(projectId) || commit.repoName,
        commits: [],
      });
    }
    groups.get(commit.repoName)!.commits.push({
      sha: commit.sha,
      authorName: commit.authorName,
      userId: commit.userId,
      message: commit.message,
      additions: commit.additions || 0,
      deletions: commit.deletions || 0,
      committedAt: commit.committedAt,
    });
  }

  // 按时间排序每组的 commits
  for (const group of groups.values()) {
    group.commits.sort((a, b) => new Date(a.committedAt).getTime() - new Date(b.committedAt).getTime());
  }

  return Array.from(groups.values());
}

/**
 * 从各种格式中提取纯仓库名
 */
function extractRepoName(input: string): string {
  let cleaned = input.trim().replace(/\.git$/, '');
  if (cleaned.includes('://')) {
    try {
      const url = new URL(cleaned);
      const parts = url.pathname.split('/').filter(Boolean);
      return parts.length >= 2 ? parts[1] : parts[0];
    } catch { /* fall through */ }
  }
  if (cleaned.includes('/')) {
    return cleaned.split('/').pop()!;
  }
  return cleaned;
}

/**
 * 构建 AI prompt
 */
async function buildUserPrompt(group: CommitGroup): Promise<string> {
  // 获取该项目下所有现有 OKR
  const existingObjs = await db.select().from(objectives)
    .where(eq(objectives.projectId, group.projectId));

  // 获取开发人员列表（从 commits 中提取 unique userId）
  const authorIds = [...new Set(group.commits.map(c => c.userId).filter(Boolean))] as string[];
  const authorUsers = authorIds.length > 0
    ? await db.select().from(users).where(inArray(users.id, authorIds))
    : [];
  const userMap = new Map(authorUsers.map(u => [u.id, u.displayName]));

  let prompt = `仓库：${group.repoName}\n所属项目：${group.projectName}\n当前日期：${dayjs().format('YYYY-MM-DD')}\n\n`;

  // 开发人员列表
  prompt += `该仓库的开发人员（commit 提交人 → 系统用户映射）：\n`;
  for (const userId of authorIds) {
    prompt += `- userId: "${userId}", 姓名: ${userMap.get(userId) || '未知'}\n`;
  }
  prompt += '\n';

  // 已有 OKR
  if (existingObjs.length > 0) {
    prompt += '该项目已有的 OKR：\n';
    for (const obj of existingObjs) {
      const owner = obj.ownerId ? userMap.get(obj.ownerId) : null;
      prompt += `Objective: id="${obj.id}", title="${obj.title}", 负责人=${owner || '未指定'}, period=${obj.period}, 时间=${obj.startDate || '?'}~${obj.endDate || '?'}, 进度=${obj.progress || 0}%\n`;

      const krs = await db.select().from(keyResults)
        .where(eq(keyResults.objectiveId, obj.id));

      if (krs.length > 0) {
        prompt += '  Key Results:\n';
        for (const kr of krs) {
          prompt += `  - id: "${kr.id}", title: "${kr.title}", sourceKey: "${kr.sourceKey || ''}", status: ${kr.status}, 进度: ${kr.currentValue || 0}/${kr.targetValue}, 时间: ${kr.startDate || '?'}~${kr.endDate || '?'}\n`;
        }
      }
    }
  } else {
    prompt += '该项目暂无 OKR 记录。\n';
  }

  // 新增 commits
  prompt += `\n该仓库新增的提交记录（按时间排序，均为增量，之前的已处理过）：\n`;
  for (const commit of group.commits) {
    const date = dayjs(commit.committedAt).format('YYYY-MM-DD HH:mm');
    const sha7 = commit.sha.substring(0, 7);
    const name = commit.authorName || '未知';
    const userId = commit.userId || '?';
    prompt += `- [${date}] 提交人: ${name}(userId=${userId}) ${sha7}: ${commit.message || '(无消息)'} (+${commit.additions}/-${commit.deletions})\n`;
  }

  prompt += `\n请分析以上提交，返回 JSON。注意：每个 action 都必须带 ownerId 字段，值为提交人的 userId，表示该 OKR 归谁负责。
{
  "actions": [
    {
      "type": "create_objective",
      "ownerId": "提交人的userId",
      "title": "目标标题",
      "startDate": "YYYY-MM-DD",
      "endDate": "YYYY-MM-DD",
      "reasoning": "为什么要创建这个目标",
      "keyResults": [
        { "title": "...", "sourceKey": "...", "currentValue": 30, "startDate": "YYYY-MM-DD", "endDate": "YYYY-MM-DD" }
      ]
    },
    {
      "type": "create_kr",
      "ownerId": "提交人的userId",
      "objectiveId": "已有目标的id",
      "title": "...",
      "sourceKey": "...",
      "currentValue": 30,
      "startDate": "YYYY-MM-DD",
      "endDate": "YYYY-MM-DD",
      "reasoning": "..."
    },
    {
      "type": "update_progress",
      "krId": "已有KR的id",
      "newCurrentValue": 70,
      "reasoning": "..."
    },
    {
      "type": "complete_kr",
      "krId": "已有KR的id",
      "reasoning": "..."
    }
  ],
  "summary": "一句话总结该仓库近期开发动态"
}
如果没有需要操作的内容，返回 {"actions": [], "summary": "..."}`;

  return prompt;
}

/**
 * 执行 AI 返回的 actions
 */
async function executeActions(actions: AIAction[], projectId: string): Promise<number> {
  let executedCount = 0;
  const now = new Date();

  for (const action of actions) {
    try {
      switch (action.type) {
        case 'create_objective': {
          if (!action.title || !action.ownerId) break;

          const objId = uuid();
          // 计算当前季度末
          const now2 = dayjs();
          const currentQuarter = Math.ceil((now2.month() + 1) / 3);
          const quarterEnd = dayjs(`${now2.year()}-${currentQuarter * 3}-01`).endOf('month');
          const endDate = action.endDate || quarterEnd.format('YYYY-MM-DD');
          const period = dateToPeriod(endDate);

          await db.insert(objectives).values({
            id: objId,
            title: action.title,
            ownerId: action.ownerId,
            projectId,
            period,
            startDate: action.startDate || dayjs().format('YYYY-MM-DD'),
            endDate,
            progress: 0,
            source: 'ai_generated',
            createdAt: now,
            updatedAt: now,
          });

          // 创建附带的 KRs
          if (action.keyResults?.length) {
            for (const krData of action.keyResults) {
              // sourceKey 去重检查
              if (krData.sourceKey) {
                const existing = await db.select().from(keyResults)
                  .where(eq(keyResults.sourceKey, krData.sourceKey));
                if (existing.some(kr => kr.objectiveId === objId)) continue;
              }

              const krId = uuid();
              await db.insert(keyResults).values({
                id: krId,
                objectiveId: objId,
                title: krData.title,
                targetValue: 100,
                currentValue: krData.currentValue || 0,
                unit: '%',
                weight: 1,
                status: krData.currentValue >= 100 ? 'completed' : 'active',
                startDate: krData.startDate || action.startDate,
                endDate: krData.endDate || action.endDate,
                source: 'ai_generated',
                sourceKey: krData.sourceKey || null,
                createdAt: now,
                updatedAt: now,
              });

              await addAILog(krId, 'created', `AI 自动创建: ${action.reasoning || ''}`);
              executedCount++;
            }
          }

          await recalcObjectiveProgress(objId);
          executedCount++;
          console.info(`[AI-OKR] Created objective: ${action.title}`);
          break;
        }

        case 'create_kr': {
          if (!action.objectiveId || !action.title) break;

          // 验证 objective 存在
          const obj = await db.query.objectives.findFirst({
            where: eq(objectives.id, action.objectiveId),
          });
          if (!obj) {
            console.warn(`[AI-OKR] Objective ${action.objectiveId} not found, skipping create_kr`);
            break;
          }

          // sourceKey 去重
          if (action.sourceKey) {
            const existing = await db.select().from(keyResults)
              .where(eq(keyResults.sourceKey, action.sourceKey));
            if (existing.some(kr => kr.objectiveId === action.objectiveId)) {
              // 已存在同 sourceKey，转为更新进度
              const existingKR = existing.find(kr => kr.objectiveId === action.objectiveId)!;
              if (action.currentValue && action.currentValue > (existingKR.currentValue || 0)) {
                await db.update(keyResults)
                  .set({ currentValue: action.currentValue, updatedAt: now })
                  .where(eq(keyResults.id, existingKR.id));
                await addAILog(existingKR.id, 'progress_update',
                  `AI 更新（sourceKey 重复转更新）: ${existingKR.currentValue} → ${action.currentValue}`);
                await recalcObjectiveProgress(action.objectiveId);
              }
              executedCount++;
              break;
            }
          }

          const krId = uuid();
          await db.insert(keyResults).values({
            id: krId,
            objectiveId: action.objectiveId,
            title: action.title,
            targetValue: 100,
            currentValue: action.currentValue || 0,
            unit: '%',
            weight: 1,
            status: (action.currentValue || 0) >= 100 ? 'completed' : 'active',
            startDate: action.startDate || null,
            endDate: action.endDate || null,
            source: 'ai_generated',
            sourceKey: action.sourceKey || null,
            createdAt: now,
            updatedAt: now,
          });

          await addAILog(krId, 'created', `AI 自动创建: ${action.reasoning || ''}`);
          await recalcObjectiveProgress(action.objectiveId);
          executedCount++;
          console.info(`[AI-OKR] Created KR: ${action.title}`);
          break;
        }

        case 'update_progress': {
          if (!action.krId || action.newCurrentValue === undefined) break;

          const kr = await db.query.keyResults.findFirst({
            where: eq(keyResults.id, action.krId),
          });
          if (!kr) {
            console.warn(`[AI-OKR] KR ${action.krId} not found, skipping update_progress`);
            break;
          }

          // 只允许进度前进，不允许后退
          if (action.newCurrentValue <= (kr.currentValue || 0)) break;

          const clampedValue = Math.min(action.newCurrentValue, kr.targetValue);
          await db.update(keyResults)
            .set({ currentValue: clampedValue, updatedAt: now })
            .where(eq(keyResults.id, action.krId));

          await addAILog(action.krId, 'progress_update',
            `AI 更新进度: ${kr.currentValue} → ${clampedValue}，${action.reasoning || ''}`);
          await recalcObjectiveProgress(kr.objectiveId);
          executedCount++;
          console.info(`[AI-OKR] Updated KR progress: ${kr.title} → ${clampedValue}`);
          break;
        }

        case 'complete_kr': {
          if (!action.krId) break;

          const kr = await db.query.keyResults.findFirst({
            where: eq(keyResults.id, action.krId),
          });
          if (!kr) {
            console.warn(`[AI-OKR] KR ${action.krId} not found, skipping complete_kr`);
            break;
          }

          if (kr.status === 'completed') break; // 已完成则跳过

          await db.update(keyResults)
            .set({ status: 'completed', currentValue: kr.targetValue, updatedAt: now })
            .where(eq(keyResults.id, action.krId));

          await addAILog(action.krId, 'completed',
            `AI 判定完成: ${action.reasoning || ''}`);
          await recalcObjectiveProgress(kr.objectiveId);
          executedCount++;
          console.info(`[AI-OKR] Completed KR: ${kr.title}`);
          break;
        }
      }
    } catch (err) {
      const msg = err instanceof Error ? err.message : String(err);
      console.error(`[AI-OKR] Error executing action ${action.type}: ${msg}`);
    }
  }

  return executedCount;
}

/**
 * 写 KR 操作日志（AI 系统操作）
 */
async function addAILog(krId: string, action: string, detail: string) {
  await db.insert(krLogs).values({
    id: uuid(),
    krId,
    action,
    detail,
    operatorId: null,
    operatorName: 'AI System',
    createdAt: new Date(),
  });
}

/**
 * 标记 commits 为已分析
 */
async function markCommitsAnalyzed(shas: string[], batchId: string) {
  const now = new Date();
  for (const sha of shas) {
    try {
      await db.insert(aiAnalyzedCommits).values({
        id: uuid(),
        commitSha: sha,
        batchId,
        createdAt: now,
      });
    } catch {
      // 可能已经存在（unique constraint），忽略
    }
  }
}

// ── Main Entry ──

export interface AnalyzeResult {
  totalCommits: number;
  reposProcessed: number;
  actionsExecuted: number;
  summaries: { repo: string; summary: string }[];
}

/**
 * 分析未处理的 commits 并自动更新 OKR
 * @param dryRun 如果为 true，只返回 AI 建议不执行
 */
export async function analyzeCommitsForOKR(dryRun = false): Promise<AnalyzeResult> {
  const startTime = Date.now();
  const batchId = uuid();

  const groups = await gatherUnanalyzedCommits();

  if (groups.length === 0) {
    console.info('[AI-OKR] No unanalyzed commits found, skipping');
    return { totalCommits: 0, reposProcessed: 0, actionsExecuted: 0, summaries: [] };
  }

  let totalCommits = 0;
  let actionsExecuted = 0;
  const summaries: { repo: string; summary: string }[] = [];

  const MAX_COMMITS_PER_BATCH = 30;

  for (const group of groups) {
    try {
      totalCommits += group.commits.length;

      // 分批处理，每批最多 30 条 commits
      const batches: typeof group.commits[] = [];
      for (let i = 0; i < group.commits.length; i += MAX_COMMITS_PER_BATCH) {
        batches.push(group.commits.slice(i, i + MAX_COMMITS_PER_BATCH));
      }

      for (let batchIdx = 0; batchIdx < batches.length; batchIdx++) {
        const batchCommits = batches[batchIdx];
        const batchGroup = { ...group, commits: batchCommits };
        console.info(`[AI-OKR] Analyzing ${batchCommits.length} commits for repo: ${group.repoName} (batch ${batchIdx + 1}/${batches.length})`);

        // 构建 prompt 并调用 AI
        const userPrompt = await buildUserPrompt(batchGroup);
        const rawResponse = await callLLM(SYSTEM_PROMPT, userPrompt);
        const aiResponse = parseLLMJson<AIResponse>(rawResponse);

        if (!aiResponse.actions || !Array.isArray(aiResponse.actions)) {
          console.warn(`[AI-OKR] Invalid AI response for ${group.repoName}, skipping batch`);
          await markCommitsAnalyzed(batchCommits.map(c => c.sha), batchId);
          continue;
        }

        if (batchIdx === batches.length - 1) {
          summaries.push({ repo: group.repoName, summary: aiResponse.summary || '' });
        }

        if (!dryRun) {
          const count = await executeActions(aiResponse.actions, group.projectId);
          actionsExecuted += count;
          await markCommitsAnalyzed(batchCommits.map(c => c.sha), batchId);
        } else {
          console.info(`[AI-OKR] [DRY RUN] Would execute ${aiResponse.actions.length} actions for ${group.repoName}`);
          actionsExecuted += aiResponse.actions.length;
        }
      }
    } catch (err) {
      const msg = err instanceof Error ? err.message : String(err);
      console.error(`[AI-OKR] Failed to analyze repo ${group.repoName}: ${msg}`);
    }
  }

  // 记录 sync log
  const elapsed = Date.now() - startTime;
  await db.insert(syncLogs).values({
    id: uuid(),
    source: 'ai_okr',
    status: 'success',
    message: `${dryRun ? '[DRY RUN] ' : ''}Analyzed ${totalCommits} commits from ${groups.length} repos, executed ${actionsExecuted} actions in ${elapsed}ms`,
    recordsProcessed: actionsExecuted,
    syncedAt: new Date(),
  });

  console.info(`[AI-OKR] Completed: ${totalCommits} commits, ${groups.length} repos, ${actionsExecuted} actions in ${elapsed}ms`);
  return { totalCommits, reposProcessed: groups.length, actionsExecuted, summaries };
}