initial boilerplate

2026-05-03 16:43:53 +03:00
parent bea266e066
commit 2e63e0e95b
18 changed files with 1878 additions and 1 deletions
@@ -0,0 +1,161 @@
+package db
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// migration holds a SQL statement and a human-readable name.
+// We run them in order and track which ones have already run.
+type migration struct {
+	name string
+	sql  string
+}
+
+var migrations = []migration{
+	{
+		name: "create_receipts",
+		sql: `
+			CREATE TABLE IF NOT EXISTS receipts (
+				id           UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+				store_name   TEXT,
+				receipt_date DATE NOT NULL,
+				image_path   TEXT,
+				city         TEXT,
+				country      TEXT DEFAULT 'US',
+				submitted_at TIMESTAMPTZ NOT NULL DEFAULT now()
+			);
+		`,
+	},
+	{
+		name: "create_canonical_items",
+		sql: `
+			-- The "dictionary" of known items we track.
+			-- User submissions get mapped to these via fuzzy matching.
+			CREATE TABLE IF NOT EXISTS canonical_items (
+				name        TEXT PRIMARY KEY,      -- e.g. "milk_whole_1gal"
+				display_name TEXT NOT NULL,        -- e.g. "Whole Milk, 1 Gallon"
+				category    TEXT NOT NULL,         -- e.g. "dairy"
+				unit        TEXT,                  -- e.g. "gallon", "lb", "dozen"
+				aliases     TEXT[] DEFAULT '{}'    -- ["1 gal whole milk", "milk whole gal"]
+			);
+		`,
+	},
+	{
+		name: "create_line_items",
+		sql: `
+			CREATE TABLE IF NOT EXISTS line_items (
+				id                UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+				receipt_id        UUID NOT NULL REFERENCES receipts(id) ON DELETE CASCADE,
+				raw_name          TEXT NOT NULL,
+				canonical_name    TEXT REFERENCES canonical_items(name),
+				price_cents       INT NOT NULL CHECK (price_cents > 0),
+				quantity          NUMERIC(8,3) NOT NULL DEFAULT 1,
+				-- Stored computed column: unit price in cents
+				unit_price_cents  INT GENERATED ALWAYS AS
+				                    (ROUND(price_cents / quantity)::INT) STORED
+			);
+
+			CREATE INDEX IF NOT EXISTS line_items_receipt_id ON line_items(receipt_id);
+			CREATE INDEX IF NOT EXISTS line_items_canonical  ON line_items(canonical_name);
+		`,
+	},
+	{
+		name: "create_price_snapshots",
+		sql: `
+			-- Pre-aggregated monthly averages, rebuilt by a background job.
+			-- Charts read from here rather than scanning all line_items each time.
+			CREATE TABLE IF NOT EXISTS price_snapshots (
+				canonical_name   TEXT NOT NULL REFERENCES canonical_items(name),
+				year_month       DATE NOT NULL,  -- always the 1st of the month
+				avg_price_cents  INT  NOT NULL,
+				sample_count     INT  NOT NULL DEFAULT 0,
+				PRIMARY KEY (canonical_name, year_month)
+			);
+		`,
+	},
+	{
+		name: "seed_canonical_items",
+		sql: `
+			INSERT INTO canonical_items (name, display_name, category, unit, aliases) VALUES
+				('milk_whole_1gal',  'Whole Milk, 1 Gallon',    'dairy',   'gallon',
+				 ARRAY['whole milk gallon', '1 gal whole milk', 'milk whl gal']),
+				('eggs_large_dozen', 'Large Eggs, 1 Dozen',     'dairy',   'dozen',
+				 ARRAY['large eggs 12ct', 'eggs large dozen', 'grade a large eggs']),
+				('bread_white_loaf', 'White Bread, 1 Loaf',     'bakery',  'loaf',
+				 ARRAY['white bread', 'sandwich bread', 'bread loaf']),
+				('ground_beef_1lb',  'Ground Beef, 1 lb (80%)', 'meat',    'lb',
+				 ARRAY['ground beef lb', '80/20 ground beef', 'hamburger meat']),
+				('olive_oil_16oz',   'Olive Oil, 16 oz',        'pantry',  'bottle',
+				 ARRAY['olive oil 16oz', 'extra virgin olive oil', 'evoo 16oz']),
+				('butter_salted_1lb','Salted Butter, 1 lb',     'dairy',   'lb',
+				 ARRAY['butter salted pound', 'salted butter 4 sticks']),
+				('chicken_breast_1lb','Chicken Breast, 1 lb',   'meat',    'lb',
+				 ARRAY['boneless chicken breast', 'chicken breast lb']),
+				('orange_juice_52oz','Orange Juice, 52 oz',     'beverages','carton',
+				 ARRAY['oj 52oz', 'orange juice carton', 'florida natural oj'])
+			ON CONFLICT (name) DO NOTHING;
+		`,
+	},
+}
+
+// Migrate runs all pending migrations in order.
+// It creates a simple tracking table on first run.
+func Migrate(pool *pgxpool.Pool) error {
+	ctx := context.Background()
+
+	// Create the migrations tracking table if it doesn't exist
+	_, err := pool.Exec(ctx, `
+		CREATE TABLE IF NOT EXISTS schema_migrations (
+			name       TEXT PRIMARY KEY,
+			applied_at TIMESTAMPTZ NOT NULL DEFAULT now()
+		);
+	`)
+	if err != nil {
+		return fmt.Errorf("create migrations table: %w", err)
+	}
+
+	for _, m := range migrations {
+		// Check if already applied
+		var exists bool
+		err := pool.QueryRow(ctx,
+			"SELECT EXISTS(SELECT 1 FROM schema_migrations WHERE name = $1)", m.name,
+		).Scan(&exists)
+		if err != nil {
+			return fmt.Errorf("check migration %s: %w", m.name, err)
+		}
+
+		if exists {
+			continue
+		}
+
+		// Run the migration inside a transaction so it's atomic
+		tx, err := pool.Begin(ctx)
+		if err != nil {
+			return fmt.Errorf("begin migration %s: %w", m.name, err)
+		}
+
+		if _, err := tx.Exec(ctx, m.sql); err != nil {
+			_ = tx.Rollback(ctx)
+			return fmt.Errorf("run migration %s: %w", m.name, err)
+		}
+
+		if _, err := tx.Exec(ctx,
+			"INSERT INTO schema_migrations (name) VALUES ($1)", m.name,
+		); err != nil {
+			_ = tx.Rollback(ctx)
+			return fmt.Errorf("record migration %s: %w", m.name, err)
+		}
+
+		if err := tx.Commit(ctx); err != nil {
+			return fmt.Errorf("commit migration %s: %w", m.name, err)
+		}
+
+		slog.Info("migration applied", "name", m.name)
+	}
+
+	return nil
+}