-- TravelHub: multi-tenant flight booking schema
-- Strategy: shared database, shared schema, tenant_id discriminator on every
-- tenant-owned table. Reference data (airports, airlines) is global.

CREATE EXTENSION IF NOT EXISTS "pgcrypto";

-- ---------------------------------------------------------------- tenants --
CREATE TABLE IF NOT EXISTS tenants (
    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    slug        TEXT        NOT NULL UNIQUE,
    name        TEXT        NOT NULL,
    status      TEXT        NOT NULL DEFAULT 'active'
                CHECK (status IN ('active', 'suspended')),
    created_at  TIMESTAMPTZ NOT NULL DEFAULT now()
);

-- ------------------------------------------------------------------ users --
CREATE TABLE IF NOT EXISTS users (
    id             UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    tenant_id      UUID        NOT NULL REFERENCES tenants(id) ON DELETE CASCADE,
    email          TEXT        NOT NULL,
    password_hash  TEXT        NOT NULL,
    full_name      TEXT        NOT NULL,
    role           TEXT        NOT NULL DEFAULT 'agent'
                   CHECK (role IN ('admin', 'agent')),
    created_at     TIMESTAMPTZ NOT NULL DEFAULT now(),
    -- The same email may exist in different tenants; unique only within one.
    CONSTRAINT users_tenant_email_key UNIQUE (tenant_id, email)
);
CREATE INDEX IF NOT EXISTS idx_users_tenant ON users(tenant_id);

-- ------------------------------------------------- reference data (global) --
CREATE TABLE IF NOT EXISTS airports (
    id           UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    iata_code    CHAR(3) NOT NULL UNIQUE,
    name         TEXT    NOT NULL,
    city         TEXT    NOT NULL,
    country      TEXT    NOT NULL,
    timezone     TEXT    NOT NULL DEFAULT 'UTC'
);

CREATE TABLE IF NOT EXISTS airlines (
    id         UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    iata_code  CHAR(2) NOT NULL UNIQUE,
    name       TEXT    NOT NULL,
    logo_url   TEXT
);

-- ---------------------------------------------------------------- flights --
-- Inventory is per-tenant: each agency loads its own negotiated fares.
CREATE TABLE IF NOT EXISTS flights (
    id                      UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    tenant_id               UUID        NOT NULL REFERENCES tenants(id) ON DELETE CASCADE,
    airline_id              UUID        NOT NULL REFERENCES airlines(id),
    flight_number           TEXT        NOT NULL,
    origin_airport_id       UUID        NOT NULL REFERENCES airports(id),
    destination_airport_id  UUID        NOT NULL REFERENCES airports(id),
    departure_time          TIMESTAMPTZ NOT NULL,
    arrival_time            TIMESTAMPTZ NOT NULL,
    aircraft                TEXT        NOT NULL DEFAULT '',
    cabin_class             TEXT        NOT NULL DEFAULT 'economy'
                            CHECK (cabin_class IN ('economy', 'premium_economy', 'business', 'first')),
    base_price              NUMERIC(10,2) NOT NULL CHECK (base_price >= 0),
    currency                CHAR(3)     NOT NULL DEFAULT 'USD',
    seats_total             INTEGER     NOT NULL CHECK (seats_total > 0),
    seats_available         INTEGER     NOT NULL CHECK (seats_available >= 0),
    status                  TEXT        NOT NULL DEFAULT 'scheduled'
                            CHECK (status IN ('scheduled', 'delayed', 'cancelled')),
    created_at              TIMESTAMPTZ NOT NULL DEFAULT now(),
    CONSTRAINT flights_seats_check CHECK (seats_available <= seats_total),
    CONSTRAINT flights_times_check CHECK (arrival_time > departure_time)
);
CREATE INDEX IF NOT EXISTS idx_flights_search
    ON flights(tenant_id, origin_airport_id, destination_airport_id, departure_time);

-- --------------------------------------------------------------- bookings --
CREATE TABLE IF NOT EXISTS bookings (
    id                 UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    tenant_id          UUID        NOT NULL REFERENCES tenants(id) ON DELETE CASCADE,
    user_id            UUID        NOT NULL REFERENCES users(id),
    flight_id          UUID        NOT NULL REFERENCES flights(id),
    booking_reference  TEXT        NOT NULL,
    passenger_count    INTEGER     NOT NULL CHECK (passenger_count > 0),
    total_amount       NUMERIC(10,2) NOT NULL CHECK (total_amount >= 0),
    currency           CHAR(3)     NOT NULL DEFAULT 'USD',
    status             TEXT        NOT NULL DEFAULT 'confirmed'
                       CHECK (status IN ('confirmed', 'cancelled')),
    contact_email      TEXT        NOT NULL,
    contact_phone      TEXT        NOT NULL DEFAULT '',
    created_at         TIMESTAMPTZ NOT NULL DEFAULT now(),
    -- PNR is unique per tenant, not globally.
    CONSTRAINT bookings_tenant_ref_key UNIQUE (tenant_id, booking_reference)
);
CREATE INDEX IF NOT EXISTS idx_bookings_tenant_created ON bookings(tenant_id, created_at DESC);

-- ------------------------------------------------------------- passengers --
CREATE TABLE IF NOT EXISTS passengers (
    id               UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    tenant_id        UUID NOT NULL REFERENCES tenants(id) ON DELETE CASCADE,
    booking_id       UUID NOT NULL REFERENCES bookings(id) ON DELETE CASCADE,
    first_name       TEXT NOT NULL,
    last_name        TEXT NOT NULL,
    date_of_birth    DATE,
    passport_number  TEXT NOT NULL DEFAULT '',
    seat_number      TEXT NOT NULL DEFAULT ''
);
CREATE INDEX IF NOT EXISTS idx_passengers_booking ON passengers(booking_id);