-- ITSM-Plattform: PostgreSQL-Schema
-- Mandantenfaehig (mehrere Organisationen auf einer Instanz, Daten per tenant_id getrennt).
-- Enthaelt audit_log fuer Nachvollziehbarkeit gemaess ISO 27001 A.12.4 / DSGVO Art. 30.

CREATE TABLE IF NOT EXISTS tenants (
    id                      SERIAL PRIMARY KEY,
    name                    TEXT NOT NULL,
    created_at              TIMESTAMPTZ NOT NULL DEFAULT now(),
    dsb_name                TEXT,               -- Datenschutzbeauftragter/Kontakt
    dsb_email               TEXT,
    retention_tickets_days  INTEGER NOT NULL DEFAULT 1095,   -- DSGVO Speicherbegrenzung (Default ~3 Jahre)
    retention_audit_days    INTEGER NOT NULL DEFAULT 1825,   -- Audit-Log-Aufbewahrung (Default ~5 Jahre)
    sla_antwort_minuten     INTEGER NOT NULL DEFAULT 480,
    sla_loesung_minuten     INTEGER NOT NULL DEFAULT 2880
);

CREATE TABLE IF NOT EXISTS users (
    id             SERIAL PRIMARY KEY,
    tenant_id      INTEGER NOT NULL REFERENCES tenants(id) ON DELETE CASCADE,
    email          TEXT NOT NULL UNIQUE,
    password_hash  TEXT NOT NULL,
    role           TEXT NOT NULL DEFAULT 'agent',   -- 'admin' | 'agent'
    active         BOOLEAN NOT NULL DEFAULT TRUE,
    created_at     TIMESTAMPTZ NOT NULL DEFAULT now(),
    last_login_at  TIMESTAMPTZ
);

CREATE TABLE IF NOT EXISTS services (
    id            SERIAL PRIMARY KEY,
    tenant_id     INTEGER NOT NULL REFERENCES tenants(id) ON DELETE CASCADE,
    name          TEXT NOT NULL,
    beschreibung  TEXT,
    kategorie     TEXT,
    gebucht       BOOLEAN NOT NULL DEFAULT TRUE,
    endpoint      TEXT,
    created_at    TIMESTAMPTZ NOT NULL DEFAULT now()
);

CREATE TABLE IF NOT EXISTS tickets (
    id                   SERIAL PRIMARY KEY,
    tenant_id            INTEGER NOT NULL REFERENCES tenants(id) ON DELETE CASCADE,
    ticket_nr            TEXT NOT NULL,
    titel                TEXT NOT NULL,
    beschreibung         TEXT,
    service_id           INTEGER REFERENCES services(id) ON DELETE SET NULL,
    status               TEXT NOT NULL DEFAULT 'Offen',
    prioritaet           TEXT NOT NULL DEFAULT 'Mittel',
    kategorie            TEXT NOT NULL DEFAULT 'Task',
    zugewiesen_an        TEXT,
    ersteller_id         INTEGER REFERENCES users(id) ON DELETE SET NULL,
    fortschritt          INTEGER NOT NULL DEFAULT 0,
    sla_antwort_minuten  INTEGER,
    sla_loesung_minuten  INTEGER,
    created_at           TIMESTAMPTZ NOT NULL DEFAULT now(),
    updated_at           TIMESTAMPTZ NOT NULL DEFAULT now(),
    UNIQUE (tenant_id, ticket_nr)
);

CREATE TABLE IF NOT EXISTS ticket_timeline (
    id         SERIAL PRIMARY KEY,
    ticket_id  INTEGER NOT NULL REFERENCES tickets(id) ON DELETE CASCADE,
    tenant_id  INTEGER NOT NULL,
    zeit       TIMESTAMPTZ NOT NULL DEFAULT now(),
    akteur     TEXT,
    text       TEXT
);

CREATE TABLE IF NOT EXISTS audit_log (
    id          SERIAL PRIMARY KEY,
    tenant_id   INTEGER REFERENCES tenants(id) ON DELETE CASCADE,
    user_id     INTEGER REFERENCES users(id) ON DELETE SET NULL,
    zeit        TIMESTAMPTZ NOT NULL DEFAULT now(),
    aktion      TEXT NOT NULL,
    entity_typ  TEXT,
    entity_id   TEXT,
    details     JSONB,
    ip          TEXT
);

CREATE INDEX IF NOT EXISTS idx_tickets_tenant_status ON tickets (tenant_id, status);
CREATE INDEX IF NOT EXISTS idx_tickets_tenant_kategorie ON tickets (tenant_id, kategorie);
CREATE INDEX IF NOT EXISTS idx_timeline_ticket ON ticket_timeline (ticket_id);
CREATE INDEX IF NOT EXISTS idx_audit_tenant_zeit ON audit_log (tenant_id, zeit DESC);
CREATE INDEX IF NOT EXISTS idx_services_tenant ON services (tenant_id);
CREATE INDEX IF NOT EXISTS idx_users_tenant ON users (tenant_id);