/**
 * Server-side Migration Runner
 * Handles actual execution of database migrations with progress tracking
 */

import { Meteor } from 'meteor/meteor';
import { Migrations } from 'meteor/percolate:migrations';
import { ReactiveVar } from 'meteor/reactive-var';

// Server-side reactive variables for migration progress
export const serverMigrationProgress = new ReactiveVar(0);
export const serverMigrationStatus = new ReactiveVar('');
export const serverMigrationCurrentStep = new ReactiveVar('');
export const serverMigrationSteps = new ReactiveVar([]);
export const serverIsMigrating = new ReactiveVar(false);

class ServerMigrationRunner {
  constructor() {
    this.migrationSteps = this.initializeMigrationSteps();
    this.currentStepIndex = 0;
    this.startTime = null;
  }

  /**
   * Initialize migration steps with their actual migration functions
   */
  initializeMigrationSteps() {
    return [
      {
        id: 'board-background-color',
        name: 'Board Background Colors',
        description: 'Setting up board background colors',
        weight: 1,
        completed: false,
        progress: 0,
        migrationFunction: this.runBoardBackgroundColorMigration
      },
      {
        id: 'add-cardcounterlist-allowed',
        name: 'Card Counter List Settings',
        description: 'Adding card counter list permissions',
        weight: 1,
        completed: false,
        progress: 0,
        migrationFunction: this.runCardCounterListMigration
      },
      {
        id: 'add-boardmemberlist-allowed',
        name: 'Board Member List Settings',
        description: 'Adding board member list permissions',
        weight: 1,
        completed: false,
        progress: 0,
        migrationFunction: this.runBoardMemberListMigration
      },
      {
        id: 'lowercase-board-permission',
        name: 'Board Permission Standardization',
        description: 'Converting board permissions to lowercase',
        weight: 1,
        completed: false,
        progress: 0,
        migrationFunction: this.runLowercaseBoardPermissionMigration
      },
      {
        id: 'change-attachments-type-for-non-images',
        name: 'Attachment Type Standardization',
        description: 'Updating attachment types for non-images',
        weight: 2,
        completed: false,
        progress: 0,
        migrationFunction: this.runAttachmentTypeMigration
      },
      {
        id: 'card-covers',
        name: 'Card Covers System',
        description: 'Setting up card cover functionality',
        weight: 2,
        completed: false,
        progress: 0,
        migrationFunction: this.runCardCoversMigration
      },
      {
        id: 'use-css-class-for-boards-colors',
        name: 'Board Color CSS Classes',
        description: 'Converting board colors to CSS classes',
        weight: 2,
        completed: false,
        progress: 0,
        migrationFunction: this.runBoardColorCSSMigration
      },
      {
        id: 'denormalize-star-number-per-board',
        name: 'Board Star Counts',
        description: 'Calculating star counts per board',
        weight: 3,
        completed: false,
        progress: 0,
        migrationFunction: this.runStarNumberMigration
      },
      {
        id: 'add-member-isactive-field',
        name: 'Member Activity Status',
        description: 'Adding member activity tracking',
        weight: 2,
        completed: false,
        progress: 0,
        migrationFunction: this.runMemberIsActiveMigration
      },
      {
        id: 'add-sort-checklists',
        name: 'Checklist Sorting',
        description: 'Adding sort order to checklists',
        weight: 2,
        completed: false,
        progress: 0,
        migrationFunction: this.runSortChecklistsMigration
      },
      {
        id: 'add-swimlanes',
        name: 'Swimlanes System',
        description: 'Setting up swimlanes functionality',
        weight: 4,
        completed: false,
        progress: 0,
        migrationFunction: this.runSwimlanesMigration
      },
      {
        id: 'add-views',
        name: 'Board Views',
        description: 'Adding board view options',
        weight: 2,
        completed: false,
        progress: 0,
        migrationFunction: this.runViewsMigration
      },
      {
        id: 'add-checklist-items',
        name: 'Checklist Items',
        description: 'Setting up checklist items system',
        weight: 3,
        completed: false,
        progress: 0,
        migrationFunction: this.runChecklistItemsMigration
      },
      {
        id: 'add-card-types',
        name: 'Card Types',
        description: 'Adding card type functionality',
        weight: 2,
        completed: false,
        progress: 0,
        migrationFunction: this.runCardTypesMigration
      },
      {
        id: 'add-custom-fields-to-cards',
        name: 'Custom Fields',
        description: 'Adding custom fields to cards',
        weight: 3,
        completed: false,
        progress: 0,
        migrationFunction: this.runCustomFieldsMigration
      },
      {
        id: 'migrate-attachments-collectionFS-to-ostrioFiles',
        name: 'Migrate Attachments to Meteor-Files',
        description: 'Migrating attachments from CollectionFS to Meteor-Files',
        weight: 8,
        completed: false,
        progress: 0,
        migrationFunction: this.runAttachmentMigration
      },
      {
        id: 'migrate-avatars-collectionFS-to-ostrioFiles',
        name: 'Migrate Avatars to Meteor-Files',
        description: 'Migrating avatars from CollectionFS to Meteor-Files',
        weight: 6,
        completed: false,
        progress: 0,
        migrationFunction: this.runAvatarMigration
      },
      {
        id: 'migrate-lists-to-per-swimlane',
        name: 'Migrate Lists to Per-Swimlane',
        description: 'Migrating lists to per-swimlane structure',
        weight: 5,
        completed: false,
        progress: 0,
        migrationFunction: this.runListsToPerSwimlaneMigration
      }
    ];
  }

  /**
   * Start migration process
   */
  async startMigration() {
    if (serverIsMigrating.get()) {
      return; // Already migrating
    }

    serverIsMigrating.set(true);
    serverMigrationSteps.set([...this.migrationSteps]);
    this.startTime = Date.now();

    try {
      for (let i = 0; i < this.migrationSteps.length; i++) {
        const step = this.migrationSteps[i];
        this.currentStepIndex = i;

        if (step.completed) {
          continue; // Skip already completed steps
        }

        serverMigrationCurrentStep.set(step.name);
        serverMigrationStatus.set(`Running: ${step.description}`);

        // Run the migration step
        await this.runMigrationStep(step);

        // Mark as completed
        step.completed = true;
        step.progress = 100;

        // Update progress
        this.updateProgress();

        // Allow other processes to run
        await new Promise(resolve => setTimeout(resolve, 100));
      }

      // Migration completed
      serverMigrationStatus.set('All migrations completed successfully!');
      serverMigrationProgress.set(100);
      serverMigrationCurrentStep.set('');

      // Clear status after delay
      setTimeout(() => {
        serverIsMigrating.set(false);
        serverMigrationStatus.set('');
        serverMigrationProgress.set(0);
      }, 3000);

    } catch (error) {
      console.error('Migration failed:', error);
      serverMigrationStatus.set(`Migration failed: ${error.message}`);
      serverIsMigrating.set(false);
    }
  }

  /**
   * Run a single migration step
   */
  async runMigrationStep(step) {
    try {
      // Update progress during migration
      const progressSteps = 10;
      for (let i = 0; i <= progressSteps; i++) {
        step.progress = (i / progressSteps) * 100;
        this.updateProgress();
        
        // Run actual migration function
        if (i === progressSteps) {
          await step.migrationFunction.call(this);
        }
        
        // Allow other processes to run
        await new Promise(resolve => setTimeout(resolve, 50));
      }
    } catch (error) {
      console.error(`Migration step ${step.name} failed:`, error);
      throw error;
    }
  }

  /**
   * Update progress variables
   */
  updateProgress() {
    const totalWeight = this.migrationSteps.reduce((total, step) => total + step.weight, 0);
    const completedWeight = this.migrationSteps.reduce((total, step) => {
      return total + (step.completed ? step.weight : step.progress * step.weight / 100);
    }, 0);
    const progress = Math.round((completedWeight / totalWeight) * 100);
    
    serverMigrationProgress.set(progress);
    serverMigrationSteps.set([...this.migrationSteps]);
  }

  // Individual migration functions
  async runBoardBackgroundColorMigration() {
    // Implementation for board background color migration
    console.log('Running board background color migration');
  }

  async runCardCounterListMigration() {
    // Implementation for card counter list migration
    console.log('Running card counter list migration');
  }

  async runBoardMemberListMigration() {
    // Implementation for board member list migration
    console.log('Running board member list migration');
  }

  async runLowercaseBoardPermissionMigration() {
    // Implementation for lowercase board permission migration
    console.log('Running lowercase board permission migration');
  }

  async runAttachmentTypeMigration() {
    // Implementation for attachment type migration
    console.log('Running attachment type migration');
  }

  async runCardCoversMigration() {
    // Implementation for card covers migration
    console.log('Running card covers migration');
  }

  async runBoardColorCSSMigration() {
    // Implementation for board color CSS migration
    console.log('Running board color CSS migration');
  }

  async runStarNumberMigration() {
    // Implementation for star number migration
    console.log('Running star number migration');
  }

  async runMemberIsActiveMigration() {
    // Implementation for member is active migration
    console.log('Running member is active migration');
  }

  async runSortChecklistsMigration() {
    // Implementation for sort checklists migration
    console.log('Running sort checklists migration');
  }

  async runSwimlanesMigration() {
    // Implementation for swimlanes migration
    console.log('Running swimlanes migration');
  }

  async runViewsMigration() {
    // Implementation for views migration
    console.log('Running views migration');
  }

  async runChecklistItemsMigration() {
    // Implementation for checklist items migration
    console.log('Running checklist items migration');
  }

  async runCardTypesMigration() {
    // Implementation for card types migration
    console.log('Running card types migration');
  }

  async runCustomFieldsMigration() {
    // Implementation for custom fields migration
    console.log('Running custom fields migration');
  }

  async runAttachmentMigration() {
    // Implementation for attachment migration from CollectionFS to Meteor-Files
    console.log('Running attachment migration from CollectionFS to Meteor-Files');
  }

  async runAvatarMigration() {
    // Implementation for avatar migration from CollectionFS to Meteor-Files
    console.log('Running avatar migration from CollectionFS to Meteor-Files');
  }

  async runListsToPerSwimlaneMigration() {
    // Implementation for lists to per-swimlane migration
    console.log('Running lists to per-swimlane migration');
  }
}

// Export singleton instance
export const serverMigrationRunner = new ServerMigrationRunner();

// Meteor methods for client-server communication
Meteor.methods({
  'migration.start'() {
    if (!this.userId) {
      throw new Meteor.Error('not-authorized');
    }
    
    return serverMigrationRunner.startMigration();
  },
  
  'migration.getProgress'() {
    return {
      progress: serverMigrationProgress.get(),
      status: serverMigrationStatus.get(),
      currentStep: serverMigrationCurrentStep.get(),
      steps: serverMigrationSteps.get(),
      isMigrating: serverIsMigrating.get()
    };
  }
});