-- Migration: 021_location_hierarchy.sql
-- Description: Restructure location tables to use comprehensive geographic hierarchy
-- Data Source: GeoDB Cities (https://github.com/dr5hn/countries-states-cities-database)

-- ============================================================================
-- PHASE 1: Backup existing tables
-- ============================================================================

-- Rename old tables to preserve data
ALTER TABLE IF EXISTS regions RENAME TO regions_old;
ALTER TABLE IF EXISTS cities RENAME TO cities_old;

-- Drop old indexes (they will conflict)
DROP INDEX IF EXISTS idx_regions_country;
DROP INDEX IF EXISTS idx_cities_region;

-- ============================================================================
-- PHASE 2: Create new location hierarchy
-- ============================================================================

-- 2.1 Continents (formerly "regions" in GeoDB)
CREATE TABLE IF NOT EXISTS continents (
    id BIGINT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
    name VARCHAR(100) NOT NULL,
    translations TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    flag SMALLINT DEFAULT 1 NOT NULL,
    wiki_data_id VARCHAR(255)
);

COMMENT ON TABLE continents IS 'Geographic continents (Africa, Americas, Asia, Europe, Oceania, Polar)';

-- 2.2 Subregions (e.g., Northern Africa, South America)
CREATE TABLE IF NOT EXISTS subregions (
    id BIGINT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
    name VARCHAR(100) NOT NULL,
    continent_id BIGINT NOT NULL REFERENCES continents(id),
    translations TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    flag SMALLINT DEFAULT 1 NOT NULL,
    wiki_data_id VARCHAR(255)
);

CREATE INDEX idx_subregions_continent ON subregions(continent_id);
COMMENT ON TABLE subregions IS 'Geographic subregions within continents';

-- 2.3 Countries
CREATE TABLE IF NOT EXISTS countries (
    id BIGINT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
    name VARCHAR(100) NOT NULL,
    iso2 CHAR(2),
    iso3 CHAR(3),
    numeric_code CHAR(3),
    phonecode VARCHAR(255),
    capital VARCHAR(255),
    currency VARCHAR(255),
    currency_name VARCHAR(255),
    currency_symbol VARCHAR(255),
    tld VARCHAR(255),
    native VARCHAR(255),
    continent_id BIGINT REFERENCES continents(id),
    subregion_id BIGINT REFERENCES subregions(id),
    nationality VARCHAR(255),
    latitude DECIMAL(10,8),
    longitude DECIMAL(11,8),
    emoji VARCHAR(10),
    emoji_u VARCHAR(50),
    timezones TEXT,
    translations TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    flag SMALLINT DEFAULT 1 NOT NULL,
    wiki_data_id VARCHAR(255)
);

CREATE INDEX idx_countries_iso2 ON countries(iso2);
CREATE INDEX idx_countries_iso3 ON countries(iso3);
CREATE INDEX idx_countries_continent ON countries(continent_id);
CREATE INDEX idx_countries_subregion ON countries(subregion_id);
COMMENT ON TABLE countries IS 'All countries with ISO codes, currencies, and metadata';

-- 2.4 States/Provinces
CREATE TABLE IF NOT EXISTS states (
    id BIGINT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
    name VARCHAR(255) NOT NULL,
    country_id BIGINT NOT NULL REFERENCES countries(id),
    country_code CHAR(2) NOT NULL,
    iso2 VARCHAR(10),
    fips_code VARCHAR(255),
    type VARCHAR(191),
    latitude DECIMAL(10,8),
    longitude DECIMAL(11,8),
    timezone VARCHAR(255),
    translations TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    flag SMALLINT DEFAULT 1 NOT NULL,
    wiki_data_id VARCHAR(255)
);

CREATE INDEX idx_states_country ON states(country_id);
CREATE INDEX idx_states_country_code ON states(country_code);
CREATE INDEX idx_states_iso2 ON states(iso2);
COMMENT ON TABLE states IS 'States, provinces, and administrative regions';

-- 2.5 Cities
CREATE TABLE IF NOT EXISTS cities (
    id BIGINT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
    name VARCHAR(255) NOT NULL,
    state_id BIGINT NOT NULL REFERENCES states(id),
    state_code VARCHAR(255),
    country_id BIGINT NOT NULL REFERENCES countries(id),
    country_code CHAR(2) NOT NULL,
    latitude DECIMAL(10,8) NOT NULL,
    longitude DECIMAL(11,8) NOT NULL,
    population BIGINT,
    timezone VARCHAR(255),
    translations TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    flag SMALLINT DEFAULT 1 NOT NULL,
    wiki_data_id VARCHAR(255)
);

CREATE INDEX idx_cities_state ON cities(state_id);
CREATE INDEX idx_cities_country ON cities(country_id);
CREATE INDEX idx_cities_country_code ON cities(country_code);
CREATE INDEX idx_cities_population ON cities(population);
COMMENT ON TABLE cities IS 'Cities with coordinates and population data';

-- ============================================================================
-- PHASE 3: Update companies table FKs
-- ============================================================================

-- Drop old FK constraint if exists (ignore errors)
ALTER TABLE companies DROP CONSTRAINT IF EXISTS companies_region_id_fkey;
ALTER TABLE companies DROP CONSTRAINT IF EXISTS companies_city_id_fkey;

-- Update column types to BIGINT (to match new tables)
ALTER TABLE companies ALTER COLUMN region_id TYPE BIGINT USING region_id::BIGINT;
ALTER TABLE companies ALTER COLUMN city_id TYPE BIGINT USING city_id::BIGINT;

-- Rename region_id to country_id for clarity
ALTER TABLE companies RENAME COLUMN region_id TO country_id;

-- Add new FK constraints (without REFERENCES for now - data will be populated by seeder)
-- These will be validated after seeder populates the data

-- Update indexes
DROP INDEX IF EXISTS idx_companies_region;
CREATE INDEX idx_companies_country ON companies(country_id);
CREATE INDEX idx_companies_city ON companies(city_id);

-- Add comments
COMMENT ON COLUMN companies.country_id IS 'Reference to countries table';
COMMENT ON COLUMN companies.city_id IS 'Reference to cities table';