-- Migration 030: Create A/B Test Results Table
-- Creates table for storing A/B testing pipeline results and deployment decisions

CREATE TABLE IF NOT EXISTS ab_test_results (
    -- Primary identifiers
    test_id VARCHAR(100) PRIMARY KEY,

    -- Test configuration
    control_model VARCHAR(100) NOT NULL,
    treatment_model VARCHAR(100) NOT NULL,
    symbol VARCHAR(20) NOT NULL,
    traffic_split DOUBLE PRECISION NOT NULL DEFAULT 0.5,
    min_sample_size INTEGER NOT NULL DEFAULT 1000,

    -- Test status
    status VARCHAR(50) NOT NULL DEFAULT 'running',
    start_time TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    end_time TIMESTAMPTZ,

    -- Control group metrics
    control_predictions BIGINT DEFAULT 0,
    control_correct_predictions BIGINT DEFAULT 0,
    control_win_rate DOUBLE PRECISION DEFAULT 0.0,
    control_total_pnl DOUBLE PRECISION DEFAULT 0.0,
    control_sharpe DOUBLE PRECISION DEFAULT 0.0,
    control_avg_latency_us DOUBLE PRECISION DEFAULT 0.0,

    -- Treatment group metrics
    treatment_predictions BIGINT DEFAULT 0,
    treatment_correct_predictions BIGINT DEFAULT 0,
    treatment_win_rate DOUBLE PRECISION DEFAULT 0.0,
    treatment_total_pnl DOUBLE PRECISION DEFAULT 0.0,
    treatment_sharpe DOUBLE PRECISION DEFAULT 0.0,
    treatment_avg_latency_us DOUBLE PRECISION DEFAULT 0.0,

    -- Statistical test results
    sharpe_diff DOUBLE PRECISION,
    sharpe_p_value DOUBLE PRECISION,
    sharpe_significant BOOLEAN,
    pnl_diff DOUBLE PRECISION,
    pnl_p_value DOUBLE PRECISION,
    pnl_significant BOOLEAN,

    -- Deployment decision (JSON)
    decision JSONB,

    -- Audit trail
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

-- Indexes for querying
CREATE INDEX idx_ab_test_results_status ON ab_test_results (status);
CREATE INDEX idx_ab_test_results_symbol ON ab_test_results (symbol);
CREATE INDEX idx_ab_test_results_start_time ON ab_test_results (start_time DESC);
CREATE INDEX idx_ab_test_results_control_model ON ab_test_results (control_model);
CREATE INDEX idx_ab_test_results_treatment_model ON ab_test_results (treatment_model);

-- Trigger to update updated_at timestamp
CREATE OR REPLACE FUNCTION update_ab_test_results_timestamp()
RETURNS TRIGGER AS $$
BEGIN
    NEW.updated_at = NOW();
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER trigger_update_ab_test_results_timestamp
    BEFORE UPDATE ON ab_test_results
    FOR EACH ROW
    EXECUTE FUNCTION update_ab_test_results_timestamp();

-- Comments
COMMENT ON TABLE ab_test_results IS 'A/B testing pipeline results for automated model deployment decisions';
COMMENT ON COLUMN ab_test_results.test_id IS 'Unique test identifier';
COMMENT ON COLUMN ab_test_results.control_model IS 'Baseline model ID (e.g., DQN_v1.0.0)';
COMMENT ON COLUMN ab_test_results.treatment_model IS 'New model ID under test (e.g., DQN_v2.0.0)';
COMMENT ON COLUMN ab_test_results.traffic_split IS 'Traffic split ratio (0.5 = 50/50)';
COMMENT ON COLUMN ab_test_results.status IS 'Test status: running, completed_rollout, completed_revert, completed_neutral, completed_inconclusive';
COMMENT ON COLUMN ab_test_results.decision IS 'JSON deployment decision: RolloutTreatment, RevertToControl, Neutral, Inconclusive';