-- =============================================================================
-- Migration: 006_pipeline_registry.sql
-- Pipeline Registry and Execution History
-- =============================================================================
--
-- Creates tables for the extensible pipeline system:
--   pipeline.registry    - Registered pipelines and their metadata
--   pipeline.executions  - Pipeline execution history
--
-- This enables dynamic pipeline discovery, registration, and execution tracking.
--
-- Date: 2026-01-24
-- =============================================================================

-- Ensure pipeline schema exists (should already exist from 005)
CREATE SCHEMA IF NOT EXISTS pipeline;


-- =============================================================================
-- SECTION 1: PIPELINE REGISTRY
-- =============================================================================

-- Pipeline registry table
-- Stores registered pipelines and their metadata for dynamic discovery
CREATE TABLE IF NOT EXISTS pipeline.registry (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),

    -- Pipeline identity
    pipeline_id VARCHAR(50) NOT NULL UNIQUE,
    name VARCHAR(255) NOT NULL,
    description TEXT,
    version VARCHAR(20) NOT NULL,

    -- Module information for dynamic loading
    module_path VARCHAR(255) NOT NULL,  -- e.g., "reviewiq_pipeline.pipeline:ReviewIQPipeline"

    -- Pipeline configuration
    stages TEXT[] NOT NULL DEFAULT '{}',
    input_type VARCHAR(100) NOT NULL DEFAULT 'dict',
    config JSONB,

    -- Status
    is_enabled BOOLEAN NOT NULL DEFAULT TRUE,

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

COMMENT ON TABLE pipeline.registry IS 'Registered pipelines available for execution';
COMMENT ON COLUMN pipeline.registry.pipeline_id IS 'Unique pipeline identifier (e.g., "reviewiq")';
COMMENT ON COLUMN pipeline.registry.module_path IS 'Python module path for dynamic import (package.module:ClassName)';
COMMENT ON COLUMN pipeline.registry.stages IS 'Ordered list of stage names';
COMMENT ON COLUMN pipeline.registry.input_type IS 'Expected input type (for documentation/validation)';
COMMENT ON COLUMN pipeline.registry.config IS 'Pipeline-specific configuration as JSON';

-- Indexes for registry
CREATE INDEX IF NOT EXISTS idx_registry_enabled
    ON pipeline.registry (is_enabled)
    WHERE is_enabled = TRUE;


-- =============================================================================
-- SECTION 2: EXECUTION HISTORY
-- =============================================================================

-- Execution status enum
DO $$ BEGIN
    CREATE TYPE pipeline.execution_status AS ENUM (
        'pending',
        'running',
        'completed',
        'failed',
        'cancelled'
    );
EXCEPTION
    WHEN duplicate_object THEN NULL;
END $$;

-- Pipeline execution history
-- Tracks each pipeline execution for monitoring and debugging
CREATE TABLE IF NOT EXISTS pipeline.executions (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),

    -- Pipeline reference
    pipeline_id VARCHAR(50) NOT NULL,

    -- Optional associations
    job_id UUID,                            -- Link to scraper job (soft FK to public.jobs)
    business_id VARCHAR(255),               -- Business being processed

    -- Execution status
    status pipeline.execution_status NOT NULL DEFAULT 'pending',

    -- Stage tracking
    stages_requested TEXT[] NOT NULL DEFAULT '{}',
    stages_completed TEXT[] NOT NULL DEFAULT '{}',
    current_stage VARCHAR(100),

    -- Input/output summaries (for quick reference without loading full data)
    input_summary JSONB,
    result_summary JSONB,

    -- Error tracking
    error_message TEXT,

    -- Timestamps
    started_at TIMESTAMPTZ,
    completed_at TIMESTAMPTZ,
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

COMMENT ON TABLE pipeline.executions IS 'Pipeline execution history for monitoring and debugging';
COMMENT ON COLUMN pipeline.executions.pipeline_id IS 'Reference to pipeline.registry.pipeline_id';
COMMENT ON COLUMN pipeline.executions.job_id IS 'Optional link to scraper job (soft FK)';
COMMENT ON COLUMN pipeline.executions.stages_requested IS 'Stages requested to run';
COMMENT ON COLUMN pipeline.executions.stages_completed IS 'Stages that completed successfully';
COMMENT ON COLUMN pipeline.executions.input_summary IS 'Summary of input data (for display)';
COMMENT ON COLUMN pipeline.executions.result_summary IS 'Summary of results (for display)';

-- Indexes for execution queries
CREATE INDEX IF NOT EXISTS idx_executions_pipeline_id
    ON pipeline.executions (pipeline_id);

CREATE INDEX IF NOT EXISTS idx_executions_job_id
    ON pipeline.executions (job_id)
    WHERE job_id IS NOT NULL;

CREATE INDEX IF NOT EXISTS idx_executions_business_id
    ON pipeline.executions (business_id)
    WHERE business_id IS NOT NULL;

CREATE INDEX IF NOT EXISTS idx_executions_status
    ON pipeline.executions (status);

CREATE INDEX IF NOT EXISTS idx_executions_created_at
    ON pipeline.executions (created_at DESC);

-- Composite index for common query patterns
CREATE INDEX IF NOT EXISTS idx_executions_pipeline_status
    ON pipeline.executions (pipeline_id, status, created_at DESC);


-- =============================================================================
-- SECTION 3: TRIGGER FOR UPDATED_AT
-- =============================================================================

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

-- Trigger for registry table
DROP TRIGGER IF EXISTS tr_registry_updated_at ON pipeline.registry;
CREATE TRIGGER tr_registry_updated_at
    BEFORE UPDATE ON pipeline.registry
    FOR EACH ROW
    EXECUTE FUNCTION pipeline.update_updated_at_column();


-- =============================================================================
-- SECTION 4: INITIAL DATA
-- =============================================================================

-- Register the ReviewIQ pipeline (can be updated by the application on startup)
INSERT INTO pipeline.registry (
    pipeline_id,
    name,
    description,
    version,
    module_path,
    stages,
    input_type,
    is_enabled
)
VALUES (
    'reviewiq',
    'ReviewIQ Classification Pipeline',
    'Classifies reviews using URT taxonomy, detects issues, and aggregates metrics',
    '1.0.0',
    'reviewiq_pipeline.pipeline:ReviewIQPipeline',
    ARRAY['normalize', 'classify', 'route', 'aggregate'],
    'ScraperV1Output',
    TRUE
)
ON CONFLICT (pipeline_id) DO UPDATE SET
    name = EXCLUDED.name,
    description = EXCLUDED.description,
    version = EXCLUDED.version,
    module_path = EXCLUDED.module_path,
    stages = EXCLUDED.stages,
    input_type = EXCLUDED.input_type,
    updated_at = NOW();


-- =============================================================================
-- SECTION 5: VIEWS
-- =============================================================================

-- View for recent executions with pipeline info
CREATE OR REPLACE VIEW pipeline.executions_with_pipeline AS
SELECT
    e.id,
    e.pipeline_id,
    r.name AS pipeline_name,
    e.job_id,
    e.business_id,
    e.status,
    e.stages_requested,
    e.stages_completed,
    e.current_stage,
    e.error_message,
    e.started_at,
    e.completed_at,
    e.created_at,
    CASE
        WHEN e.status = 'running' THEN
            EXTRACT(EPOCH FROM (NOW() - e.started_at))::INTEGER
        WHEN e.completed_at IS NOT NULL THEN
            EXTRACT(EPOCH FROM (e.completed_at - e.started_at))::INTEGER
        ELSE NULL
    END AS duration_seconds
FROM pipeline.executions e
LEFT JOIN pipeline.registry r ON e.pipeline_id = r.pipeline_id;

COMMENT ON VIEW pipeline.executions_with_pipeline IS 'Executions joined with pipeline metadata and duration';


-- View for pipeline execution statistics
CREATE OR REPLACE VIEW pipeline.execution_stats AS
SELECT
    pipeline_id,
    COUNT(*) AS total_executions,
    COUNT(*) FILTER (WHERE status = 'completed') AS completed_count,
    COUNT(*) FILTER (WHERE status = 'failed') AS failed_count,
    COUNT(*) FILTER (WHERE status = 'running') AS running_count,
    COUNT(*) FILTER (WHERE status = 'cancelled') AS cancelled_count,
    AVG(EXTRACT(EPOCH FROM (completed_at - started_at)))
        FILTER (WHERE status = 'completed') AS avg_duration_seconds,
    MAX(created_at) AS last_execution_at
FROM pipeline.executions
GROUP BY pipeline_id;

COMMENT ON VIEW pipeline.execution_stats IS 'Aggregated execution statistics per pipeline';


-- =============================================================================
-- DONE
-- =============================================================================