import {
  Controller,
  Get,
  Post,
  Delete,
  Param,
  Body,
  UseGuards,
  ForbiddenException,
} from '@nestjs/common';
import { JwtAuthGuard } from '../auth/jwt-auth.guard';
import { TenantId } from '../tenant/tenant.decorator';
import { CurrentUser } from '../auth/current-user.decorator';
import { TenantDatabaseService } from '../tenant/tenant-database.service';
import { RecordShare } from '../models/record-share.model';
import { ObjectDefinition } from '../models/object-definition.model';
import { User } from '../models/user.model';
import { AuthorizationService } from './authorization.service';
import { CreateRecordShareDto } from './dto/create-record-share.dto';

@Controller('runtime/objects/:objectApiName/records/:recordId/shares')
@UseGuards(JwtAuthGuard)
export class RecordSharingController {
  constructor(
    private tenantDbService: TenantDatabaseService,
    private authService: AuthorizationService,
  ) {}

  @Get()
  async getRecordShares(
    @TenantId() tenantId: string,
    @Param('objectApiName') objectApiName: string,
    @Param('recordId') recordId: string,
    @CurrentUser() currentUser: any,
  ) {
    const resolvedTenantId = await this.tenantDbService.resolveTenantId(tenantId);
    const knex = await this.tenantDbService.getTenantKnexById(resolvedTenantId);

    // Get object definition
    const objectDef = await ObjectDefinition.query(knex)
      .findOne({ apiName: objectApiName });

    if (!objectDef) {
      throw new Error('Object not found');
    }

    // Get the record to check ownership
    const tableName = this.getTableName(objectDef.apiName);
    const record = await knex(tableName)
      .where({ id: recordId })
      .first();

    if (!record) {
      throw new Error('Record not found');
    }

    // Only owner can view shares
    if (record.ownerId !== currentUser.userId) {
      // Check if user has modify all permission
      const user: any = await User.query(knex)
        .findById(currentUser.userId)
        .withGraphFetched('roles.objectPermissions');

      if (!user) {
        throw new ForbiddenException('User not found');
      }

      const hasModifyAll = user.roles?.some(role =>
        role.objectPermissions?.some(
          perm => perm.objectDefinitionId === objectDef.id && perm.canModifyAll
        )
      );

      if (!hasModifyAll) {
        throw new ForbiddenException('Only the record owner or users with Modify All permission can view shares');
      }
    }

    // Get all active shares for this record
    const shares = await RecordShare.query(knex)
      .where({ objectDefinitionId: objectDef.id, recordId })
      .whereNull('revokedAt')
      .where(builder => {
        builder.whereNull('expiresAt').orWhere('expiresAt', '>', new Date());
      })
      .withGraphFetched('[granteeUser]')
      .orderBy('createdAt', 'desc');

    return shares;
  }

  @Post()
  async createRecordShare(
    @TenantId() tenantId: string,
    @Param('objectApiName') objectApiName: string,
    @Param('recordId') recordId: string,
    @CurrentUser() currentUser: any,
    @Body() data: CreateRecordShareDto,
  ) {
    const resolvedTenantId = await this.tenantDbService.resolveTenantId(tenantId);
    const knex = await this.tenantDbService.getTenantKnexById(resolvedTenantId);

    // Get object definition
    const objectDef = await ObjectDefinition.query(knex)
      .findOne({ apiName: objectApiName });

    if (!objectDef) {
      throw new Error('Object not found');
    }

    // Get the record to check ownership
    const tableName = this.getTableName(objectDef.apiName);
    const record = await knex(tableName)
      .where({ id: recordId })
      .first();

    if (!record) {
      throw new Error('Record not found');
    }

    // Check if user can share - either owner or has modify permissions
    const canShare = await this.canUserShareRecord(
      currentUser.userId,
      record,
      objectDef,
      knex,
    );

    if (!canShare) {
      throw new ForbiddenException('You do not have permission to share this record');
    }

    // Cannot share with self
    if (data.granteeUserId === currentUser.userId) {
      throw new Error('Cannot share record with yourself');
    }

    // Check if share already exists
    const existingShare = await RecordShare.query(knex)
      .where({
        objectDefinitionId: objectDef.id,
        recordId,
        granteeUserId: data.granteeUserId,
      })
      .whereNull('revokedAt')
      .first();

    if (existingShare) {
      // Update existing share
      const updated = await RecordShare.query(knex)
        .patchAndFetchById(existingShare.id, {
          accessLevel: {
            canRead: data.canRead,
            canEdit: data.canEdit,
            canDelete: data.canDelete,
          },
          // Convert ISO string to MySQL datetime format
          expiresAt: data.expiresAt 
            ? knex.raw('?', [new Date(data.expiresAt).toISOString().slice(0, 19).replace('T', ' ')]) 
            : null,
        } as any);

      return RecordShare.query(knex)
        .findById(updated.id)
        .withGraphFetched('[granteeUser]');
    }

    // Create new share
    const share = await RecordShare.query(knex).insertAndFetch({
      objectDefinitionId: objectDef.id,
      recordId,
      granteeUserId: data.granteeUserId,
      grantedByUserId: currentUser.userId,
      accessLevel: {
        canRead: data.canRead,
        canEdit: data.canEdit,
        canDelete: data.canDelete,
      },
      // Convert ISO string to MySQL datetime format: YYYY-MM-DD HH:MM:SS
      expiresAt: data.expiresAt 
        ? knex.raw('?', [new Date(data.expiresAt).toISOString().slice(0, 19).replace('T', ' ')]) 
        : null,
    } as any);

    return RecordShare.query(knex)
      .findById(share.id)
      .withGraphFetched('[granteeUser]');
  }

  @Delete(':shareId')
  async deleteRecordShare(
    @TenantId() tenantId: string,
    @Param('objectApiName') objectApiName: string,
    @Param('recordId') recordId: string,
    @Param('shareId') shareId: string,
    @CurrentUser() currentUser: any,
  ) {
    const resolvedTenantId = await this.tenantDbService.resolveTenantId(tenantId);
    const knex = await this.tenantDbService.getTenantKnexById(resolvedTenantId);

    // Get object definition
    const objectDef = await ObjectDefinition.query(knex)
      .findOne({ apiName: objectApiName });

    if (!objectDef) {
      throw new Error('Object not found');
    }

    // Get the record to check ownership
    const tableName = this.getTableName(objectDef.apiName);
    const record = await knex(tableName)
      .where({ id: recordId })
      .first();

    if (!record) {
      throw new Error('Record not found');
    }

    // Only owner can revoke shares
    if (record.ownerId !== currentUser.userId) {
      // Check if user has modify all permission
      const user: any = await User.query(knex)
        .findById(currentUser.userId)
        .withGraphFetched('roles.objectPermissions');

      if (!user) {
        throw new ForbiddenException('User not found');
      }

      const hasModifyAll = user.roles?.some(role =>
        role.objectPermissions?.some(
          perm => perm.objectDefinitionId === objectDef.id && perm.canModifyAll
        )
      );

      if (!hasModifyAll) {
        throw new ForbiddenException('Only the record owner or users with Modify All permission can revoke shares');
      }
    }

    // Revoke the share (soft delete)
    await RecordShare.query(knex)
      .patchAndFetchById(shareId, {
        revokedAt: knex.fn.now() as any,
      });

    return { success: true };
  }

  private async canUserShareRecord(
    userId: string,
    record: any,
    objectDef: ObjectDefinition,
    knex: any,
  ): Promise<boolean> {
    // Owner can always share
    if (record.ownerId === userId) {
      return true;
    }

    // Check if user has modify all or edit permissions
    const user: any = await User.query(knex)
      .findById(userId)
      .withGraphFetched('roles.objectPermissions');

    if (!user) {
      return false;
    }

    // Check for canModifyAll permission
    const hasModifyAll = user.roles?.some(role =>
      role.objectPermissions?.some(
        perm => perm.objectDefinitionId === objectDef.id && perm.canModifyAll
      )
    );

    if (hasModifyAll) {
      return true;
    }

    // Check for canEdit permission (user needs edit to share)
    const hasEdit = user.roles?.some(role =>
      role.objectPermissions?.some(
        perm => perm.objectDefinitionId === objectDef.id && perm.canEdit
      )
    );

    // If user has edit permission, check if they can actually edit this record
    // by using the authorization service
    if (hasEdit) {
      try {
        await this.authService.assertCanPerformAction(
          'update',
          objectDef,
          record,
          user,
          knex,
        );
        return true;
      } catch {
        return false;
      }
    }

    return false;
  }

  private getTableName(apiName: string): string {
    // Convert CamelCase to snake_case and pluralize
    const snakeCase = apiName
      .replace(/([A-Z])/g, '_$1')
      .toLowerCase()
      .replace(/^_/, '');
    
    // Simple pluralization
    if (snakeCase.endsWith('y')) {
      return snakeCase.slice(0, -1) + 'ies';
    } else if (snakeCase.endsWith('s')) {
      return snakeCase + 'es';
    } else {
      return snakeCase + 's';
    }
  }
}