-- Migration 005: Upload Workflow Enhancements
-- Adds status tracking and error handling for uploads

-- ============================================
-- Add status column to uploads table
-- ============================================
DO $$ 
BEGIN
    IF NOT EXISTS (SELECT 1 FROM information_schema.columns 
                   WHERE table_name = 'uploads' AND column_name = 'status') THEN
        ALTER TABLE uploads ADD COLUMN status VARCHAR(20) DEFAULT 'completed' NOT NULL;
    END IF;
END $$;

-- ============================================
-- Add error_message column for failed uploads
-- ============================================
DO $$ 
BEGIN
    IF NOT EXISTS (SELECT 1 FROM information_schema.columns 
                   WHERE table_name = 'uploads' AND column_name = 'error_message') THEN
        ALTER TABLE uploads ADD COLUMN error_message TEXT;
    END IF;
END $$;

-- ============================================
-- Add client_checksum column for verification
-- ============================================
DO $$ 
BEGIN
    IF NOT EXISTS (SELECT 1 FROM information_schema.columns 
                   WHERE table_name = 'uploads' AND column_name = 'client_checksum') THEN
        ALTER TABLE uploads ADD COLUMN client_checksum VARCHAR(64);
    END IF;
END $$;

-- ============================================
-- Add indexes for upload status queries
-- ============================================
CREATE INDEX IF NOT EXISTS idx_uploads_status ON uploads(status);
CREATE INDEX IF NOT EXISTS idx_uploads_status_uploaded_at ON uploads(status, uploaded_at);

-- ============================================
-- Add constraint to validate status values
-- ============================================
DO $$ 
BEGIN
    IF NOT EXISTS (SELECT 1 FROM information_schema.constraint_column_usage 
                   WHERE constraint_name = 'check_upload_status') THEN
        ALTER TABLE uploads ADD CONSTRAINT check_upload_status 
            CHECK (status IN ('pending', 'completed', 'failed'));
    END IF;
END $$;

-- ============================================
-- Create table for tracking in-progress uploads (for 409 conflict detection)
-- ============================================
CREATE TABLE IF NOT EXISTS upload_locks (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    sha256_hash VARCHAR(64) NOT NULL,
    package_id UUID NOT NULL REFERENCES packages(id) ON DELETE CASCADE,
    locked_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
    locked_by VARCHAR(255) NOT NULL,
    expires_at TIMESTAMP WITH TIME ZONE NOT NULL,
    UNIQUE(sha256_hash, package_id)
);

CREATE INDEX IF NOT EXISTS idx_upload_locks_expires_at ON upload_locks(expires_at);
CREATE INDEX IF NOT EXISTS idx_upload_locks_hash_package ON upload_locks(sha256_hash, package_id);

-- ============================================
-- Function to clean up expired upload locks
-- ============================================
CREATE OR REPLACE FUNCTION cleanup_expired_upload_locks()
RETURNS INTEGER AS $$
DECLARE
    deleted_count INTEGER;
BEGIN
    DELETE FROM upload_locks WHERE expires_at < NOW();
    GET DIAGNOSTICS deleted_count = ROW_COUNT;
    RETURN deleted_count;
END;
$$ LANGUAGE plpgsql;