import { QueryInterface, DataTypes } from 'sequelize';

export const up = async (queryInterface: QueryInterface) => {
    // 1. Drop and recreate the enum type for snapshot_type to ensure all values are included
    // This ensures APPROVE is always present when table is recreated
    // Note: Table should be dropped manually before running this migration
    try {
        await queryInterface.sequelize.query(`
            DO $$ 
            BEGIN
                -- Drop enum if it exists (cascade will handle any dependencies)
                IF EXISTS (SELECT 1 FROM pg_type WHERE typname = 'enum_dealer_claim_history_snapshot_type') THEN
                    DROP TYPE IF EXISTS enum_dealer_claim_history_snapshot_type CASCADE;
                END IF;
                
                -- Create enum with all values including APPROVE
                CREATE TYPE enum_dealer_claim_history_snapshot_type AS ENUM ('PROPOSAL', 'COMPLETION', 'INTERNAL_ORDER', 'WORKFLOW', 'APPROVE');
            END $$;
        `);
    } catch (error) {
        // If enum creation fails, log error but continue
        console.error('Enum creation error:', error);
        throw error;
    }

    // 2. Create new simplified level-based dealer_claim_history table
    await queryInterface.createTable('dealer_claim_history', {
        history_id: {
            type: DataTypes.UUID,
            defaultValue: DataTypes.UUIDV4,
            primaryKey: true
        },
        request_id: {
            type: DataTypes.UUID,
            allowNull: false,
            references: {
                model: 'workflow_requests',
                key: 'request_id'
            },
            onUpdate: 'CASCADE',
            onDelete: 'CASCADE'
        },
        approval_level_id: {
            type: DataTypes.UUID,
            allowNull: true, // Nullable for workflow-level snapshots
            references: {
                model: 'approval_levels',
                key: 'level_id'
            },
            onUpdate: 'CASCADE',
            onDelete: 'SET NULL'
        },
        level_number: {
            type: DataTypes.INTEGER,
            allowNull: true, // Nullable for workflow-level snapshots
            comment: 'Level number for easier querying (e.g., 1=Dealer, 3=Dept Lead, 4/5=Completion)'
        },
        level_name: {
            type: DataTypes.STRING(255),
            allowNull: true, // Nullable for workflow-level snapshots
            comment: 'Level name for consistent matching (e.g., "Dealer Proposal Submission", "Department Lead Approval")'
        },
        version: {
            type: DataTypes.INTEGER,
            allowNull: false,
            comment: 'Version number for this specific level (starts at 1 per level)'
        },
        snapshot_type: {
            type: DataTypes.ENUM('PROPOSAL', 'COMPLETION', 'INTERNAL_ORDER', 'WORKFLOW', 'APPROVE'),
            allowNull: false,
            comment: 'Type of snapshot: PROPOSAL (Step 1), COMPLETION (Step 4/5), INTERNAL_ORDER (Step 3), WORKFLOW (general), APPROVE (approver actions with comments)'
        },
        snapshot_data: {
            type: DataTypes.JSONB,
            allowNull: false,
            comment: 'JSON object containing all snapshot data specific to this level and type. Structure varies by snapshot_type.'
        },
        change_reason: {
            type: DataTypes.TEXT,
            allowNull: true,
            comment: 'Reason for this version change (e.g., "Revision Requested: ...")'
        },
        changed_by: {
            type: DataTypes.UUID,
            allowNull: false,
            references: {
                model: 'users',
                key: 'user_id'
            }
        },
        created_at: {
            type: DataTypes.DATE,
            allowNull: false,
            defaultValue: DataTypes.NOW
        }
    });

    // Add indexes for efficient querying
    await queryInterface.addIndex('dealer_claim_history', ['request_id', 'level_number', 'version'], {
        name: 'idx_history_request_level_version'
    });
    await queryInterface.addIndex('dealer_claim_history', ['approval_level_id', 'version'], {
        name: 'idx_history_level_version'
    });
    await queryInterface.addIndex('dealer_claim_history', ['request_id', 'snapshot_type'], {
        name: 'idx_history_request_type'
    });
    await queryInterface.addIndex('dealer_claim_history', ['snapshot_type', 'level_number'], {
        name: 'idx_history_type_level'
    });
    await queryInterface.addIndex('dealer_claim_history', ['request_id', 'level_name'], {
        name: 'idx_history_request_level_name'
    });
    await queryInterface.addIndex('dealer_claim_history', ['level_name', 'snapshot_type'], {
        name: 'idx_history_level_name_type'
    });
    // Index for JSONB queries on snapshot_data
    await queryInterface.addIndex('dealer_claim_history', ['snapshot_type'], {
        name: 'idx_history_snapshot_type',
        using: 'BTREE'
    });
};

export const down = async (queryInterface: QueryInterface) => {
    // Note: Table should be dropped manually
    // Drop the enum type
    try {
        await queryInterface.sequelize.query(`
            DROP TYPE IF EXISTS enum_dealer_claim_history_snapshot_type CASCADE;
        `);
    } catch (error) {
        console.warn('Enum drop warning:', error);
    }
};