-- Migration 002: Schema Enhancements
-- Adds new fields, indexes, and triggers for improved functionality

-- ============================================
-- Packages: Add format and platform fields
-- ============================================
ALTER TABLE packages ADD COLUMN IF NOT EXISTS format VARCHAR(50) DEFAULT 'generic';
ALTER TABLE packages ADD COLUMN IF NOT EXISTS platform VARCHAR(50) DEFAULT 'any';

CREATE INDEX IF NOT EXISTS idx_packages_format ON packages(format);
CREATE INDEX IF NOT EXISTS idx_packages_platform ON packages(platform);

-- ============================================
-- Artifacts: Add checksum_md5, metadata, and CHECK constraints
-- ============================================
ALTER TABLE artifacts ADD COLUMN IF NOT EXISTS checksum_md5 VARCHAR(32);
ALTER TABLE artifacts ADD COLUMN IF NOT EXISTS metadata JSONB;

-- Add CHECK constraints (will fail if data violates them)
DO $$
BEGIN
    IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'artifacts_ref_count_check') THEN
        ALTER TABLE artifacts ADD CONSTRAINT artifacts_ref_count_check CHECK (ref_count >= 0);
    END IF;
    IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'artifacts_size_check') THEN
        ALTER TABLE artifacts ADD CONSTRAINT artifacts_size_check CHECK (size > 0);
    END IF;
END $$;

CREATE INDEX IF NOT EXISTS idx_artifacts_metadata ON artifacts USING GIN (metadata);

-- ============================================
-- Tags: Add updated_at and composite index
-- ============================================
ALTER TABLE tags ADD COLUMN IF NOT EXISTS updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW();

CREATE INDEX IF NOT EXISTS idx_tags_package_created_at ON tags(package_id, created_at DESC);

-- ============================================
-- Tag History: Add change_type and index
-- ============================================
ALTER TABLE tag_history ADD COLUMN IF NOT EXISTS change_type VARCHAR(20) DEFAULT 'update';

DO $$
BEGIN
    IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'tag_history_change_type_check') THEN
        ALTER TABLE tag_history ADD CONSTRAINT tag_history_change_type_check
            CHECK (change_type IN ('create', 'update', 'delete'));
    END IF;
END $$;

CREATE INDEX IF NOT EXISTS idx_tag_history_changed_at ON tag_history(changed_at);

-- ============================================
-- Uploads: Add new fields and composite indexes
-- ============================================
ALTER TABLE uploads ADD COLUMN IF NOT EXISTS tag_name VARCHAR(255);
ALTER TABLE uploads ADD COLUMN IF NOT EXISTS user_agent VARCHAR(512);
ALTER TABLE uploads ADD COLUMN IF NOT EXISTS duration_ms INTEGER;
ALTER TABLE uploads ADD COLUMN IF NOT EXISTS deduplicated BOOLEAN DEFAULT false;
ALTER TABLE uploads ADD COLUMN IF NOT EXISTS checksum_verified BOOLEAN DEFAULT true;

CREATE INDEX IF NOT EXISTS idx_uploads_package_uploaded_at ON uploads(package_id, uploaded_at DESC);
CREATE INDEX IF NOT EXISTS idx_uploads_uploaded_by_at ON uploads(uploaded_by, uploaded_at DESC);

-- ============================================
-- Audit Logs: Add composite indexes and GIN index
-- ============================================
CREATE INDEX IF NOT EXISTS idx_audit_logs_resource_timestamp ON audit_logs(resource, timestamp DESC);
CREATE INDEX IF NOT EXISTS idx_audit_logs_user_timestamp ON audit_logs(user_id, timestamp DESC);
CREATE INDEX IF NOT EXISTS idx_audit_logs_details ON audit_logs USING GIN (details);

-- ============================================
-- Projects: Add partial index for public projects
-- ============================================
CREATE INDEX IF NOT EXISTS idx_projects_public ON projects(name) WHERE is_public = true;

-- ============================================
-- Triggers: Update tag_changes trigger for change_type
-- ============================================
CREATE OR REPLACE FUNCTION track_tag_changes()
RETURNS TRIGGER AS $$
BEGIN
    IF TG_OP = 'UPDATE' AND OLD.artifact_id != NEW.artifact_id THEN
        INSERT INTO tag_history (id, tag_id, old_artifact_id, new_artifact_id, change_type, changed_at, changed_by)
        VALUES (gen_random_uuid(), NEW.id, OLD.artifact_id, NEW.artifact_id, 'update', NOW(), NEW.created_by);
    END IF;
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

-- ============================================
-- Triggers: Auto-update updated_at timestamps
-- ============================================
CREATE OR REPLACE FUNCTION update_updated_at_column()
RETURNS TRIGGER AS $$
BEGIN
    NEW.updated_at = NOW();
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

-- Drop triggers if they exist, then recreate
DROP TRIGGER IF EXISTS projects_updated_at_trigger ON projects;
CREATE TRIGGER projects_updated_at_trigger
    BEFORE UPDATE ON projects
    FOR EACH ROW
    EXECUTE FUNCTION update_updated_at_column();

DROP TRIGGER IF EXISTS packages_updated_at_trigger ON packages;
CREATE TRIGGER packages_updated_at_trigger
    BEFORE UPDATE ON packages
    FOR EACH ROW
    EXECUTE FUNCTION update_updated_at_column();

DROP TRIGGER IF EXISTS tags_updated_at_trigger ON tags;
CREATE TRIGGER tags_updated_at_trigger
    BEFORE UPDATE ON tags
    FOR EACH ROW
    EXECUTE FUNCTION update_updated_at_column();

-- ============================================
-- Triggers: Maintain artifact ref_count accuracy
-- ============================================
CREATE OR REPLACE FUNCTION increment_artifact_ref_count()
RETURNS TRIGGER AS $$
BEGIN
    UPDATE artifacts SET ref_count = ref_count + 1 WHERE id = NEW.artifact_id;
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE FUNCTION decrement_artifact_ref_count()
RETURNS TRIGGER AS $$
BEGIN
    UPDATE artifacts SET ref_count = ref_count - 1 WHERE id = OLD.artifact_id;
    RETURN OLD;
END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE FUNCTION update_artifact_ref_count()
RETURNS TRIGGER AS $$
BEGIN
    IF OLD.artifact_id != NEW.artifact_id THEN
        UPDATE artifacts SET ref_count = ref_count - 1 WHERE id = OLD.artifact_id;
        UPDATE artifacts SET ref_count = ref_count + 1 WHERE id = NEW.artifact_id;
    END IF;
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

-- Note: ref_count triggers on tags table
-- These track how many tags reference each artifact
DROP TRIGGER IF EXISTS tags_ref_count_insert_trigger ON tags;
CREATE TRIGGER tags_ref_count_insert_trigger
    AFTER INSERT ON tags
    FOR EACH ROW
    EXECUTE FUNCTION increment_artifact_ref_count();

DROP TRIGGER IF EXISTS tags_ref_count_delete_trigger ON tags;
CREATE TRIGGER tags_ref_count_delete_trigger
    AFTER DELETE ON tags
    FOR EACH ROW
    EXECUTE FUNCTION decrement_artifact_ref_count();

DROP TRIGGER IF EXISTS tags_ref_count_update_trigger ON tags;
CREATE TRIGGER tags_ref_count_update_trigger
    AFTER UPDATE ON tags
    FOR EACH ROW
    EXECUTE FUNCTION update_artifact_ref_count();