/**
 * Checkpoints API Routes
 *
 * 提供 Checkpoint 管理的 REST API
 */

import { Hono } from 'hono';
import { getConfig } from './config.js';
import type {
  CheckpointMetadata,
  CheckpointConfig,
  CheckpointTrigger,
  FileChange,
  FileChangeType,
  DiffInfo,
  FileDiff,
  RollbackOptions,
  RollbackResult,
  RollbackRecord,
  SafetyCheckResult,
  UnrevertResult,
} from '@ai-assistant/core';
import {
  CheckpointManager,
  getCheckpointManager,
  initCheckpointManager,
  RestoreMode,
} from '@ai-assistant/core';

interface CheckpointStats {
  count: number;
  oldestTimestamp: number | null;
  newestTimestamp: number | null;
}

export const checkpointsRouter = new Hono();

// Manager 初始化状态
let managerInitialized = false;

/**
 * 初始化 Checkpoint 模块
 */
async function ensureCheckpointManager(): Promise<CheckpointManager | null> {
  if (managerInitialized) {
    return getCheckpointManager();
  }

  try {
    const config = getConfig();
    await initCheckpointManager(config.workdir);
    managerInitialized = true;
    console.log('[Checkpoints] Checkpoint module initialized');
    return getCheckpointManager();
  } catch (error) {
    console.warn('[Checkpoints] Failed to initialize Checkpoint module:', error);
    return null;
  }
}

/**
 * GET /checkpoints - 获取所有检查点列表
 */
checkpointsRouter.get('/', async (c) => {
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    const checkpoints = await manager.listCheckpoints();

    return c.json({
      success: true,
      data: checkpoints.map((cp) => ({
        id: cp.id,
        name: cp.name,
        description: cp.description,
        timestamp: cp.timestamp,
        trigger: cp.trigger,
        filesChanged: cp.filesChanged,
        commitHash: cp.commitHash,
        messageId: cp.messageId,
        sessionId: cp.sessionId,
      })),
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to list checkpoints',
      },
      500
    );
  }
});

/**
 * GET /checkpoints/stats - 获取检查点统计信息
 */
checkpointsRouter.get('/stats', async (c) => {
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    const stats = await manager.getStats();

    return c.json({
      success: true,
      data: stats,
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to get stats',
      },
      500
    );
  }
});

/**
 * GET /checkpoints/latest - 获取最新检查点
 */
checkpointsRouter.get('/latest', async (c) => {
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    const checkpoint = await manager.getLatestCheckpoint();

    return c.json({
      success: true,
      data: checkpoint,
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to get latest checkpoint',
      },
      500
    );
  }
});

/**
 * GET /checkpoints/unrevert/status - 检查是否可撤销回滚
 */
checkpointsRouter.get('/unrevert/status', async (c) => {
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    const canUnrevert = manager.canUnrevert();
    const lastRollback = manager.getLastRollback();

    return c.json({
      success: true,
      data: {
        canUnrevert,
        lastRollback: lastRollback
          ? {
              id: lastRollback.id,
              timestamp: lastRollback.timestamp,
              targetCheckpoint: lastRollback.targetCheckpoint,
              restoredFiles: lastRollback.restoredFiles,
            }
          : null,
      },
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to get unrevert status',
      },
      500
    );
  }
});

/**
 * GET /checkpoints/:id - 获取单个检查点详情
 */
checkpointsRouter.get('/:id', async (c) => {
  const id = c.req.param('id');
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    const checkpoint = await manager.getCheckpoint(id);

    if (!checkpoint) {
      return c.json(
        {
          success: false,
          error: `Checkpoint not found: ${id}`,
        },
        404
      );
    }

    return c.json({
      success: true,
      data: checkpoint,
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to get checkpoint',
      },
      500
    );
  }
});

/**
 * POST /checkpoints - 创建手动检查点
 */
checkpointsRouter.post('/', async (c) => {
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    const body = await c.req.json<{ name?: string; description?: string }>();

    const checkpoint = await manager.createCheckpoint({
      name: body.name,
      description: body.description,
      trigger: 'manual',
    });

    return c.json({
      success: true,
      data: checkpoint,
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to create checkpoint',
      },
      500
    );
  }
});

/**
 * DELETE /checkpoints/:id - 删除检查点
 */
checkpointsRouter.delete('/:id', async (c) => {
  const id = c.req.param('id');
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    const deleted = await manager.deleteCheckpoint(id);

    if (!deleted) {
      return c.json(
        {
          success: false,
          error: `Checkpoint not found: ${id}`,
        },
        404
      );
    }

    return c.json({
      success: true,
      data: { deleted: true },
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to delete checkpoint',
      },
      500
    );
  }
});

/**
 * GET /checkpoints/:id/diff - 获取检查点与当前工作区的差异
 */
checkpointsRouter.get('/:id/diff', async (c) => {
  const id = c.req.param('id');
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    const diff = await manager.getDiff(id);

    return c.json({
      success: true,
      data: diff,
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to get diff',
      },
      500
    );
  }
});

/**
 * GET /checkpoints/:id/file-diff - 获取单个文件的详细差异
 */
checkpointsRouter.get('/:id/file-diff', async (c) => {
  const id = c.req.param('id');
  const filePath = c.req.query('path');
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  if (!filePath) {
    return c.json(
      {
        success: false,
        error: 'File path is required',
      },
      400
    );
  }

  try {
    const fileDiff = await manager.getFileDiff(id, filePath);

    return c.json({
      success: true,
      data: fileDiff,
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to get file diff',
      },
      500
    );
  }
});

/**
 * POST /checkpoints/:id/restore - 回滚到检查点
 */
checkpointsRouter.post('/:id/restore', async (c) => {
  const id = c.req.param('id');
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    const body = await c.req.json<{
      mode?: 'ai_changes_only' | 'workspace_only' | 'full';
      files?: string[];
      skipSafetyCheck?: boolean;
    }>();

    // 转换 mode 字符串为枚举值
    let mode: RestoreMode | undefined;
    if (body.mode) {
      switch (body.mode) {
        case 'ai_changes_only':
          mode = RestoreMode.AI_CHANGES_ONLY;
          break;
        case 'workspace_only':
          mode = RestoreMode.WORKSPACE_ONLY;
          break;
        case 'full':
          mode = RestoreMode.FULL;
          break;
      }
    }

    const result = await manager.rollback({
      target: id,
      mode,
      files: body.files,
      skipSafetyCheck: body.skipSafetyCheck,
    });

    return c.json({
      success: true,
      data: result,
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to restore checkpoint',
      },
      500
    );
  }
});

/**
 * GET /checkpoints/:id/restore/preview - 预览回滚（dry run）
 */
checkpointsRouter.get('/:id/restore/preview', async (c) => {
  const id = c.req.param('id');
  const modeParam = c.req.query('mode');
  const filesParam = c.req.query('files');
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    // 转换 mode 字符串为枚举值
    let mode: RestoreMode | undefined;
    if (modeParam) {
      switch (modeParam) {
        case 'ai_changes_only':
          mode = RestoreMode.AI_CHANGES_ONLY;
          break;
        case 'workspace_only':
          mode = RestoreMode.WORKSPACE_ONLY;
          break;
        case 'full':
          mode = RestoreMode.FULL;
          break;
      }
    }

    const files = filesParam ? filesParam.split(',') : undefined;

    const result = await manager.rollback({
      target: id,
      mode,
      files,
      dryRun: true,
    });

    return c.json({
      success: true,
      data: result,
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to preview restore',
      },
      500
    );
  }
});

/**
 * POST /checkpoints/unrevert - 撤销最近一次回滚
 */
checkpointsRouter.post('/unrevert', async (c) => {
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    const result = await manager.unrevert();

    if (!result.success) {
      return c.json(
        {
          success: false,
          error: result.error || 'Failed to unrevert',
        },
        400
      );
    }

    return c.json({
      success: true,
      data: result,
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to unrevert',
      },
      500
    );
  }
});

/**
 * GET /checkpoints/:id/safety-check - 执行安全检查
 */
checkpointsRouter.get('/:id/safety-check', async (c) => {
  const id = c.req.param('id');
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    const result = await manager.checkSafety(id);

    return c.json({
      success: true,
      data: result,
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to check safety',
      },
      500
    );
  }
});

/**
 * POST /checkpoints/cleanup - 清理过期检查点
 */
checkpointsRouter.post('/cleanup', async (c) => {
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    const deleted = await manager.cleanup();

    return c.json({
      success: true,
      data: { deleted },
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to cleanup',
      },
      500
    );
  }
});

/**
 * GET /checkpoints/sessions/:sessionId - 获取会话的所有检查点
 */
checkpointsRouter.get('/sessions/:sessionId', async (c) => {
  const sessionId = c.req.param('sessionId');
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    const checkpoints = await manager.getSessionCheckpoints(sessionId);

    return c.json({
      success: true,
      data: checkpoints,
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to get session checkpoints',
      },
      500
    );
  }
});

/**
 * GET /checkpoints/messages/:messageId - 获取消息关联的检查点
 */
checkpointsRouter.get('/messages/:messageId', async (c) => {
  const messageId = c.req.param('messageId');
  const manager = await ensureCheckpointManager();

  if (!manager) {
    return c.json(
      {
        success: false,
        error: 'Checkpoint module not available',
      },
      503
    );
  }

  try {
    const checkpoints = await manager.getMessageCheckpoints(messageId);

    return c.json({
      success: true,
      data: checkpoints,
    });
  } catch (error) {
    return c.json(
      {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to get message checkpoints',
      },
      500
    );
  }
});