-- Migration: Add package_versions table for separate version tracking
-- This separates immutable versions from mutable tags

-- Create package_versions table
CREATE TABLE IF NOT EXISTS package_versions (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    package_id UUID NOT NULL REFERENCES packages(id) ON DELETE CASCADE,
    artifact_id VARCHAR(64) NOT NULL REFERENCES artifacts(id),
    version VARCHAR(255) NOT NULL,
    version_source VARCHAR(50),  -- 'explicit', 'filename', 'metadata', 'migrated_from_tag'
    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
    created_by VARCHAR(255) NOT NULL,
    UNIQUE(package_id, version),
    UNIQUE(package_id, artifact_id)
);

-- Indexes for common queries
CREATE INDEX IF NOT EXISTS idx_package_versions_package_id ON package_versions(package_id);
CREATE INDEX IF NOT EXISTS idx_package_versions_artifact_id ON package_versions(artifact_id);
CREATE INDEX IF NOT EXISTS idx_package_versions_package_version ON package_versions(package_id, version);

-- Trigger functions for ref_count management (same pattern as tags)
CREATE OR REPLACE FUNCTION increment_version_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_version_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 triggers
DROP TRIGGER IF EXISTS package_versions_ref_count_insert ON package_versions;
CREATE TRIGGER package_versions_ref_count_insert
    AFTER INSERT ON package_versions
    FOR EACH ROW
    EXECUTE FUNCTION increment_version_ref_count();

DROP TRIGGER IF EXISTS package_versions_ref_count_delete ON package_versions;
CREATE TRIGGER package_versions_ref_count_delete
    AFTER DELETE ON package_versions
    FOR EACH ROW
    EXECUTE FUNCTION decrement_version_ref_count();

-- Data migration: populate from existing semver-pattern tags
-- This extracts versions from tags that look like version numbers
-- Tags like "v1.0.0", "1.2.3", "2.0.0-beta" will be migrated
-- Tags like "latest", "stable", "dev" will NOT be migrated
INSERT INTO package_versions (package_id, artifact_id, version, version_source, created_by, created_at)
SELECT
    t.package_id,
    t.artifact_id,
    -- Strip leading 'v' if present
    CASE WHEN t.name LIKE 'v%' THEN substring(t.name from 2) ELSE t.name END,
    'migrated_from_tag',
    t.created_by,
    t.created_at
FROM tags t
WHERE t.name ~ '^v?[0-9]+\.[0-9]+(\.[0-9]+)?([-.][a-zA-Z0-9]+)?$'
ON CONFLICT (package_id, version) DO NOTHING;