-- Mart: Toronto Purchase Market Analysis
-- Final analytical table for purchase/sales data visualization
-- Grain: One row per district per month

with purchases as (
    select * from {{ ref('int_purchases__monthly') }}
),

-- Add year-over-year calculations
with_yoy as (
    select
        p.*,

        -- Previous year same month values
        lag(p.avg_price, 12) over (
            partition by p.district_code
            order by p.date_key
        ) as avg_price_prev_year,

        lag(p.sales_count, 12) over (
            partition by p.district_code
            order by p.date_key
        ) as sales_count_prev_year,

        lag(p.median_price, 12) over (
            partition by p.district_code
            order by p.date_key
        ) as median_price_prev_year

    from purchases p
),

final as (
    select
        purchase_id,
        date_key,
        full_date,
        year,
        month,
        quarter,
        month_name,
        district_key,
        district_code,
        district_name,
        area_type,
        sales_count,
        dollar_volume,
        avg_price,
        median_price,
        new_listings,
        active_listings,
        days_on_market,
        sale_to_list_ratio,
        absorption_rate,
        months_of_inventory,

        -- Year-over-year changes
        case
            when avg_price_prev_year > 0
            then round(((avg_price - avg_price_prev_year) / avg_price_prev_year) * 100, 2)
            else null
        end as avg_price_yoy_pct,

        case
            when sales_count_prev_year > 0
            then round(((sales_count - sales_count_prev_year)::numeric / sales_count_prev_year) * 100, 2)
            else null
        end as sales_count_yoy_pct,

        case
            when median_price_prev_year > 0
            then round(((median_price - median_price_prev_year) / median_price_prev_year) * 100, 2)
            else null
        end as median_price_yoy_pct

    from with_yoy
)

select * from final