-- Migration 028: IACE Clarifications — Multi-User-Workflow
-- ==========================================================================
-- Up to Phase 2 the Klaerungen feature persisted answers in
-- iace_projects.metadata.clarification_answers (JSONB). That works for a
-- single user but cannot model assigned_to, comment threads, status
-- history or audit trail. Phase 3 introduces a proper relational table.
--
-- The previous JSONB blob remains read by the engine as fallback for any
-- project whose clarifications have not yet been migrated, so this is a
-- non-breaking add-on. A separate one-shot upcopy script migrates the
-- existing JSONB answers into rows.
-- ==========================================================================

-- 1. Main table: one row per (project, clarification_id)
CREATE TABLE IF NOT EXISTS iace_clarifications (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    tenant_id UUID NOT NULL,
    project_id UUID NOT NULL REFERENCES iace_projects(id) ON DELETE CASCADE,
    -- Deterministic clarification ID generated by the engine
    -- (e.g. "pattern:HP1640:0", "manuf:fanuc:dual-check-safety-dcs:1").
    -- Stable across re-inits so persisted answers survive.
    clarification_key TEXT NOT NULL,
    -- The verbatim question + source as known at last engine run.
    -- Kept in this table so the audit trail does not break if the
    -- pattern library is later updated.
    question TEXT NOT NULL,
    source TEXT NOT NULL,
    category TEXT NOT NULL,
    norm_references TEXT[] DEFAULT '{}',
    -- Lifecycle state
    status TEXT NOT NULL DEFAULT 'open'
        CHECK (status IN ('open', 'in_progress', 'answered', 'not_relevant')),
    answer TEXT DEFAULT '' CHECK (answer IN ('', 'ja', 'nein', 'teilweise')),
    reasoning TEXT DEFAULT '',
    -- Multi-User workflow
    assigned_to TEXT DEFAULT '',  -- user id / kuerzel — free text for now
    answered_by TEXT DEFAULT '',
    answered_at TIMESTAMPTZ,
    -- Common audit
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    UNIQUE (project_id, clarification_key)
);

CREATE INDEX IF NOT EXISTS idx_iace_clar_project ON iace_clarifications(project_id);
CREATE INDEX IF NOT EXISTS idx_iace_clar_tenant ON iace_clarifications(tenant_id);
CREATE INDEX IF NOT EXISTS idx_iace_clar_status ON iace_clarifications(project_id, status);
CREATE INDEX IF NOT EXISTS idx_iace_clar_assignee ON iace_clarifications(assigned_to) WHERE assigned_to <> '';

-- 2. Comment thread: one row per comment, ordered by created_at
CREATE TABLE IF NOT EXISTS iace_clarification_comments (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    clarification_id UUID NOT NULL REFERENCES iace_clarifications(id) ON DELETE CASCADE,
    author TEXT NOT NULL DEFAULT '',
    body TEXT NOT NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

CREATE INDEX IF NOT EXISTS idx_iace_clar_comments_clar ON iace_clarification_comments(clarification_id, created_at);

-- 3. Status history — every status / answer change is logged.
CREATE TABLE IF NOT EXISTS iace_clarification_history (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    clarification_id UUID NOT NULL REFERENCES iace_clarifications(id) ON DELETE CASCADE,
    actor TEXT NOT NULL DEFAULT '',
    from_status TEXT,
    to_status TEXT,
    from_answer TEXT,
    to_answer TEXT,
    note TEXT DEFAULT '',
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

CREATE INDEX IF NOT EXISTS idx_iace_clar_history_clar ON iace_clarification_history(clarification_id, created_at);

-- 4. Trigger to bump updated_at on the main table
CREATE OR REPLACE FUNCTION iace_clarifications_touch_updated_at()
RETURNS TRIGGER AS $$
BEGIN
    NEW.updated_at = NOW();
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

DROP TRIGGER IF EXISTS trg_iace_clarifications_updated_at ON iace_clarifications;
CREATE TRIGGER trg_iace_clarifications_updated_at
    BEFORE UPDATE ON iace_clarifications
    FOR EACH ROW EXECUTE FUNCTION iace_clarifications_touch_updated_at();