sojorn/go-backend/internal/database/migrations/20260205000001_ai_moderation_system.up.sql

-- Create moderation_flags table for AI-powered content moderation
CREATE TABLE IF NOT EXISTS moderation_flags (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    post_id UUID REFERENCES posts(id) ON DELETE CASCADE,
    comment_id UUID REFERENCES comments(id) ON DELETE CASCADE,
    flag_reason TEXT NOT NULL,
    scores JSONB NOT NULL,
    status TEXT NOT NULL DEFAULT 'pending' CHECK (status IN ('pending', 'approved', 'rejected', 'escalated')),
    reviewed_by UUID REFERENCES users(id),
    reviewed_at TIMESTAMP WITH TIME ZONE,
    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
    
    -- Ensure at least one of post_id or comment_id is set
    CONSTRAINT moderation_flags_content_check CHECK (
        (post_id IS NOT NULL) OR (comment_id IS NOT NULL)
    )
);

-- Add indexes for performance
CREATE INDEX IF NOT EXISTS idx_moderation_flags_post_id ON moderation_flags(post_id);
CREATE INDEX IF NOT EXISTS idx_moderation_flags_comment_id ON moderation_flags(comment_id);
CREATE INDEX IF NOT EXISTS idx_moderation_flags_status ON moderation_flags(status);
CREATE INDEX IF NOT EXISTS idx_moderation_flags_created_at ON moderation_flags(created_at);

-- Add GIN index for JSONB scores to enable efficient querying
CREATE INDEX IF NOT EXISTS idx_moderation_flags_scores_gin ON moderation_flags USING GIN(scores);

-- Add status column to users table for user moderation
ALTER TABLE users ADD COLUMN IF NOT EXISTS status TEXT DEFAULT 'active' CHECK (status IN ('active', 'suspended', 'banned'));

-- Add index for user status queries
CREATE INDEX IF NOT EXISTS idx_users_status ON users(status);

-- Create user_status_history table to track status changes
CREATE TABLE IF NOT EXISTS user_status_history (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    old_status TEXT,
    new_status TEXT NOT NULL,
    reason TEXT,
    changed_by UUID REFERENCES users(id),
    created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
);

-- Add index for user status history queries
CREATE INDEX IF NOT EXISTS idx_user_status_history_user_id ON user_status_history(user_id);
CREATE INDEX IF NOT EXISTS idx_user_status_history_created_at ON user_status_history(created_at);

-- Create trigger to update updated_at timestamp
CREATE OR REPLACE FUNCTION update_moderation_flags_updated_at()
RETURNS TRIGGER AS $$
BEGIN
    NEW.updated_at = NOW();
    RETURN NEW;
END;
$$ language 'plpgsql';

CREATE TRIGGER moderation_flags_updated_at
    BEFORE UPDATE ON moderation_flags
    FOR EACH ROW
    EXECUTE FUNCTION update_moderation_flags_updated_at();

-- Create trigger to track user status changes
CREATE OR REPLACE FUNCTION log_user_status_change()
RETURNS TRIGGER AS $$
BEGIN
    IF OLD.status IS DISTINCT FROM NEW.status THEN
        INSERT INTO user_status_history (user_id, old_status, new_status, changed_by)
        VALUES (NEW.id, OLD.status, NEW.status, NEW.id);
    END IF;
    RETURN NEW;
END;
$$ language 'plpgsql';

CREATE TRIGGER user_status_change_log
    BEFORE UPDATE ON users
    FOR EACH ROW
    EXECUTE FUNCTION log_user_status_change();

-- Grant permissions to Directus
GRANT SELECT, INSERT, UPDATE, DELETE ON moderation_flags TO directus;
GRANT SELECT, INSERT, UPDATE, DELETE ON user_status_history TO directus;
GRANT SELECT, UPDATE ON users TO directus;
GRANT USAGE ON ALL SEQUENCES IN SCHEMA public TO directus;

-- Add comments for Directus UI
COMMENT ON TABLE moderation_flags IS 'AI-powered content moderation flags for posts and comments';
COMMENT ON COLUMN moderation_flags.id IS 'Unique identifier for the moderation flag';
COMMENT ON COLUMN moderation_flags.post_id IS 'Reference to the post being moderated';
COMMENT ON COLUMN moderation_flags.comment_id IS 'Reference to the comment being moderated';
COMMENT ON COLUMN moderation_flags.flag_reason IS 'Primary reason for flag (hate, greed, delusion, etc.)';
COMMENT ON COLUMN moderation_flags.scores IS 'JSON object containing detailed analysis scores';
COMMENT ON COLUMN moderation_flags.status IS 'Current moderation status (pending, approved, rejected, escalated)';
COMMENT ON COLUMN moderation_flags.reviewed_by IS 'Admin who reviewed this flag';
COMMENT ON COLUMN moderation_flags.reviewed_at IS 'When this flag was reviewed';

COMMENT ON TABLE user_status_history IS 'History of user status changes for audit trail';
COMMENT ON COLUMN user_status_history.user_id IS 'User whose status changed';
COMMENT ON COLUMN user_status_history.old_status IS 'Previous status before change';
COMMENT ON COLUMN user_status_history.new_status IS 'New status after change';
COMMENT ON COLUMN user_status_history.reason IS 'Reason for status change';
COMMENT ON COLUMN user_status_history.changed_by IS 'Admin who made the change';

COMMENT ON COLUMN users.status IS 'Current user moderation status (active, suspended, banned)';