-- Lokasyon hiyerarşisi
CREATE TYPE location_type AS ENUM (
    'ulke', 'bolge', 'il', 'ilce', 'bucak', 'belde', 'koy', 'mahalle', 'diger'
);

CREATE TABLE locations (
    id          BIGSERIAL PRIMARY KEY,
    parent_id   BIGINT REFERENCES locations(id) ON DELETE RESTRICT,
    name        TEXT NOT NULL,
    slug        TEXT NOT NULL UNIQUE,
    type        location_type NOT NULL,
    latitude    NUMERIC(10, 7),
    longitude   NUMERIC(10, 7),
    is_active   BOOLEAN NOT NULL DEFAULT TRUE,
    created_at  TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at  TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

CREATE INDEX idx_locations_parent ON locations(parent_id);
CREATE INDEX idx_locations_type   ON locations(type);

-- Lokasyon değişiklik geçmişi
CREATE TABLE location_history (
    id            BIGSERIAL PRIMARY KEY,
    location_id   BIGINT NOT NULL REFERENCES locations(id) ON DELETE CASCADE,
    snapshot      JSONB NOT NULL,
    change_reason TEXT,
    changed_by    BIGINT,         -- users tablosu kurulunca FK eklenecek
    changed_at    TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

CREATE INDEX idx_location_history_loc ON location_history(location_id);

-- İdari birim türleri
CREATE TABLE administrative_unit_types (
    id          BIGSERIAL PRIMARY KEY,
    name        TEXT NOT NULL,
    slug        TEXT NOT NULL UNIQUE,
    description TEXT
);

-- İdari birimler
CREATE TABLE administrative_units (
    id              BIGSERIAL PRIMARY KEY,
    type_id         BIGINT NOT NULL REFERENCES administrative_unit_types(id),
    name            TEXT NOT NULL,
    established_at  DATE,
    abolished_at    DATE,
    is_active       BOOLEAN NOT NULL DEFAULT TRUE
);

CREATE INDEX idx_admin_units_type ON administrative_units(type_id);

-- Lokasyon ↔ idari birim eşlemesi
CREATE TABLE location_administrative_units (
    id          BIGSERIAL PRIMARY KEY,
    location_id BIGINT NOT NULL REFERENCES locations(id) ON DELETE CASCADE,
    unit_id     BIGINT NOT NULL REFERENCES administrative_units(id) ON DELETE CASCADE,
    valid_from  DATE NOT NULL,
    valid_until DATE,
    UNIQUE (location_id, unit_id, valid_from)
);

CREATE INDEX idx_loc_admin_units_loc  ON location_administrative_units(location_id);
CREATE INDEX idx_loc_admin_units_unit ON location_administrative_units(unit_id);