add get cities handler and improve db schema

service_a/internal/domains/meteo/handlers.go

@@ -79,6 +79,7 @@ func (h *Handler) IngestExcel(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *Handler) GetCities(w http.ResponseWriter, r *http.Request) {
+	h.ToJSON(w, http.StatusOK, app.H{"cities": h.s.GetCities(r.Context())})
 }
 
 func (h *Handler) GetMeteoData(w http.ResponseWriter, r *http.Request) {

service_a/internal/domains/meteo/repository.go

@@ -11,6 +11,7 @@ import (
 type Repository interface {
 	InsertMeteoDataTX(ctx context.Context, params InsertMeteoDataParams) (*InsertMeteoDataResult, error)
 	UpdateBatchElapsedTime(ctx context.Context, batchID int, elapsedMS int) error
+	GetCities(ctx context.Context) []string
 	GetMeteoData(ctx context.Context, params GetMeteoData) ([]MeteoData, error)
 }
 
@@ -150,10 +151,32 @@ func (pgx *pgxRepo) UpdateBatchElapsedTime(ctx context.Context, batchID int, ela
 	return nil
 }
 
-const getMeteoDataQuery = `
+const getCities = `select distinct location_name from public.meteo_data order by location_name`
+
+func (pgx *pgxRepo) GetCities(ctx context.Context) []string {
+	rows, err := pgx.Query(ctx, getCities)
+	if err != nil {
+		return []string{}
+	}
+	defer rows.Close()
+
+	var cities []string
+	for rows.Next() {
+		var city string
+		err := rows.Scan(&city)
+		if err != nil {
+			continue
+		}
+		cities = append(cities, city)
+	}
+
+	return cities
+}
+
+const getMeteoData = `
 	select location_name, date_of_register, max_temp, min_temp, rainfall, cloudiness
 	from public.meteo_data
-	where location_name = $1
+	where location_name_norm = unaccent(lower($1))
 		and date_of_register >= $2
 		and date_of_register <= $3
 	order by date_of_register desc
@@ -161,7 +184,7 @@ const getMeteoDataQuery = `
 `
 
 func (pgx *pgxRepo) GetMeteoData(ctx context.Context, params GetMeteoData) ([]MeteoData, error) {
-	rows, err := pgx.Query(ctx, getMeteoDataQuery, params.Location, params.From, params.To, params.Limit, params.Offset)
+	rows, err := pgx.Query(ctx, getMeteoData, params.Location, params.From, params.To, params.Limit, params.Offset)
 	if err != nil {
 		return nil, fmt.Errorf("error querying meteo data: %w", err)
 	}

service_a/internal/domains/meteo/service.go

@@ -49,6 +49,10 @@ func (s *Service) UpdateElapsedMS(ctx context.Context, batchID, elapsedMS int) e
 	return nil
 }
 
+func (s *Service) GetCities(ctx context.Context) []string {
+	return s.repo.GetCities(ctx)
+}
+
 func (s *Service) GetMeteoData(ctx context.Context, params GetMeteoData) ([]MeteoData, error) {
 	return s.repo.GetMeteoData(ctx, params)
 }

service_a/server/database/migrations/001_data.up.sql

@@ -1,4 +1,10 @@
 create extension citext; -- noqa
+create extension unaccent;
+
+create or replace function immutable_unaccent(text)
+returns text as $$
+  select unaccent('unaccent', $1);
+$$ language sql immutable;
 
 create table public.ingest_batch
 (
@@ -20,6 +26,7 @@ create table public.meteo_data
     batch_id int not null references public.ingest_batch (id),
 
     location_name citext not null,
+    location_name_norm text generated always as (immutable_unaccent(lower(location_name))) stored,
     date_of_register date not null,
     max_temp numeric(5, 2) not null,
     min_temp numeric(5, 2) not null,
@@ -29,7 +36,7 @@ create table public.meteo_data
     created_at timestamp not null default now()
 );
 
-create index idx_meteo_data_location_name on public.meteo_data (location_name);
+create index idx_meteo_data_location_name_norm on public.meteo_data (location_name_norm);
 
 create table public.rejected_data
 (