-- Create function for updating timestamps if it doesn't exist
CREATE OR REPLACE FUNCTION update_updated_column()
RETURNS TRIGGER AS $$
BEGIN
    NEW.updated = CURRENT_TIMESTAMP;
    RETURN NEW;
END;
$$ language 'plpgsql';

-- Create function for updating updated_at timestamps
CREATE OR REPLACE FUNCTION update_updated_at_column()
RETURNS TRIGGER AS $$
BEGIN
    NEW.updated_at = CURRENT_TIMESTAMP;
    RETURN NEW;
END;
$$ language 'plpgsql';

-- Drop tables in reverse order of dependency
DROP TABLE IF EXISTS public.settings_product CASCADE;
DROP TABLE IF EXISTS public.settings_vendor CASCADE;
DROP TABLE IF EXISTS public.settings_global CASCADE;

-- Table Definition: settings_global
CREATE TABLE public.settings_global (
    setting_key VARCHAR PRIMARY KEY,
    setting_value VARCHAR NOT NULL,
    description TEXT,
    updated_at TIMESTAMPTZ NOT NULL DEFAULT CURRENT_TIMESTAMP
);

-- Table Definition: settings_vendor
CREATE TABLE public.settings_vendor (
    vendor VARCHAR PRIMARY KEY, -- Matches products.vendor
    default_lead_time_days INT,
    default_days_of_stock INT,
    updated_at TIMESTAMPTZ NOT NULL DEFAULT CURRENT_TIMESTAMP
);
-- Index for faster lookups if needed (PK usually sufficient)
-- CREATE INDEX idx_settings_vendor_vendor ON public.settings_vendor(vendor);

-- Table Definition: settings_product
CREATE TABLE public.settings_product (
    pid INT8 PRIMARY KEY,
    lead_time_days INT, -- Overrides vendor/global
    days_of_stock INT, -- Overrides vendor/global
    safety_stock INT DEFAULT 0, -- Minimum desired stock level
    forecast_method VARCHAR DEFAULT 'standard', -- e.g., 'standard', 'seasonal'
    exclude_from_forecast BOOLEAN DEFAULT FALSE,
    updated_at TIMESTAMPTZ NOT NULL DEFAULT CURRENT_TIMESTAMP,
    CONSTRAINT fk_settings_product_pid FOREIGN KEY (pid) REFERENCES public.products(pid) ON DELETE CASCADE ON UPDATE CASCADE
);


-- Description: Inserts or updates standard default global settings.
--              Safe to rerun; will update existing keys with these default values.
-- Dependencies: `settings_global` table must exist.
-- Frequency: Run once initially, or rerun if you want to reset global defaults.

INSERT INTO public.settings_global (setting_key, setting_value, description) VALUES
    ('abc_revenue_threshold_a', '0.80', 'Revenue percentage for Class A (cumulative)'),
    ('abc_revenue_threshold_b', '0.95', 'Revenue percentage for Class B (cumulative)'),
    ('abc_calculation_basis', 'revenue_30d', 'Metric for ABC calc (revenue_30d, sales_30d, lifetime_revenue)'),
    ('abc_calculation_period', '30', 'Days period for ABC calculation if not lifetime'),
    ('default_forecast_method', 'standard', 'Default forecast method (standard, seasonal)'),
    ('default_lead_time_days', '14', 'Global default lead time in days'),
    ('default_days_of_stock', '30', 'Global default days of stock coverage target'),
    -- Set default safety stock to 0 units. Can be overridden per product.
    -- If you wanted safety stock in days, you'd store 'days' here and calculate units later.
    ('default_safety_stock_units', '0', 'Global default safety stock in units')
ON CONFLICT (setting_key) DO UPDATE SET
    setting_value = EXCLUDED.setting_value,
    description = EXCLUDED.description,
    updated_at = CURRENT_TIMESTAMP; -- Update timestamp if default value changes


      
-- Description: Creates placeholder rows in `settings_vendor` for each unique vendor
--              found in the `products` table. Does NOT set specific overrides.
--              Safe to rerun; will NOT overwrite existing vendor settings.
-- Dependencies: `settings_vendor` table must exist, `products` table populated.
-- Frequency: Run once after initial product load, or periodically if new vendors are added.

INSERT INTO public.settings_vendor (
    vendor,
    default_lead_time_days,
    default_days_of_stock
    -- updated_at will use its default CURRENT_TIMESTAMP on insert
)
SELECT
    DISTINCT p.vendor,
    -- Explicitly cast NULL to INTEGER to resolve type mismatch
    CAST(NULL AS INTEGER),
    CAST(NULL AS INTEGER)
FROM
    public.products p
WHERE
    p.vendor IS NOT NULL
    AND p.vendor <> '' -- Exclude blank vendors if necessary

ON CONFLICT (vendor) DO NOTHING; -- IMPORTANT: Do not overwrite existing vendor settings

SELECT COUNT(*) FROM public.settings_vendor; -- Verify rows were inserted

      
-- Description: Creates placeholder rows in `settings_product` for each unique product
--              found in the `products` table. Sets basic defaults but no specific overrides.
--              Safe to rerun; will NOT overwrite existing product settings.
-- Dependencies: `settings_product` table must exist, `products` table populated.
-- Frequency: Run once after initial product load, or periodically if new products are added.

INSERT INTO public.settings_product (
    pid,
    lead_time_days,         -- NULL = Inherit from Vendor/Global
    days_of_stock,          -- NULL = Inherit from Vendor/Global
    safety_stock,           -- Default to 0 units initially
    forecast_method,        -- NULL = Inherit from Global ('standard')
    exclude_from_forecast   -- Default to FALSE
    -- updated_at will use its default CURRENT_TIMESTAMP on insert
)
SELECT
    p.pid,
    CAST(NULL AS INTEGER),  -- Explicitly cast NULL to INTEGER
    CAST(NULL AS INTEGER),  -- Explicitly cast NULL to INTEGER
    COALESCE((SELECT setting_value::int FROM settings_global WHERE setting_key = 'default_safety_stock_units'), 0), -- Use global default safety stock units
    CAST(NULL AS VARCHAR), -- Cast NULL to VARCHAR for forecast_method (already varchar, but explicit)
    FALSE  -- Default: Include in forecast
FROM
    public.products p

ON CONFLICT (pid) DO NOTHING; -- IMPORTANT: Do not overwrite existing product-specific settings


-- History and status tables
CREATE TABLE IF NOT EXISTS calculate_history (
    id BIGSERIAL PRIMARY KEY,
    start_time TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP,
    end_time TIMESTAMP WITH TIME ZONE NULL,
    duration_seconds INTEGER,
    duration_minutes DECIMAL(10,2) GENERATED ALWAYS AS (duration_seconds::decimal / 60.0) STORED,
    total_products INTEGER DEFAULT 0,
    total_orders INTEGER DEFAULT 0,
    total_purchase_orders INTEGER DEFAULT 0,
    processed_products INTEGER DEFAULT 0,
    processed_orders INTEGER DEFAULT 0,
    processed_purchase_orders INTEGER DEFAULT 0,
    status calculation_status DEFAULT 'running',
    error_message TEXT,
    additional_info JSONB
);

CREATE TABLE IF NOT EXISTS calculate_status (
    module_name text PRIMARY KEY,
    last_calculation_timestamp TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS sync_status (
    table_name TEXT PRIMARY KEY,
    last_sync_timestamp TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP,
    last_sync_id BIGINT
);

CREATE TABLE IF NOT EXISTS import_history (
    id BIGSERIAL PRIMARY KEY,
    table_name VARCHAR(50) NOT NULL,
    start_time TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP,
    end_time TIMESTAMP WITH TIME ZONE NULL,
    duration_seconds INTEGER,
    duration_minutes DECIMAL(10,2) GENERATED ALWAYS AS (duration_seconds::decimal / 60.0) STORED,
    records_added INTEGER DEFAULT 0,
    records_updated INTEGER DEFAULT 0,
    records_deleted INTEGER DEFAULT 0,
    records_skipped INTEGER DEFAULT 0,
    total_processed INTEGER DEFAULT 0,
    is_incremental BOOLEAN DEFAULT FALSE,
    status calculation_status DEFAULT 'running',
    error_message TEXT,
    additional_info JSONB
);

-- Create all indexes after tables are fully created
CREATE INDEX IF NOT EXISTS idx_last_calc ON calculate_status(last_calculation_timestamp);
CREATE INDEX IF NOT EXISTS idx_last_sync ON sync_status(last_sync_timestamp);
CREATE INDEX IF NOT EXISTS idx_table_time ON import_history(table_name, start_time);
CREATE INDEX IF NOT EXISTS idx_import_history_status ON import_history(status);
CREATE INDEX IF NOT EXISTS idx_calculate_history_status ON calculate_history(status);

-- Add comments for documentation
COMMENT ON TABLE import_history IS 'Tracks history of data import operations with detailed statistics';
COMMENT ON COLUMN import_history.records_deleted IS 'Number of records deleted during this import';
COMMENT ON COLUMN import_history.records_skipped IS 'Number of records skipped (e.g., unchanged, invalid)';
COMMENT ON COLUMN import_history.total_processed IS 'Total number of records examined/processed, including skipped';

COMMENT ON TABLE calculate_history IS 'Tracks history of metrics calculation runs with performance data';
COMMENT ON COLUMN calculate_history.duration_seconds IS 'Total duration of the calculation in seconds';
COMMENT ON COLUMN calculate_history.additional_info IS 'JSON object containing step timings, row counts, and other detailed metrics';