-- Slice 8.5 — level-up proposals.
--
-- A proposal is an LLM-generated diff of "current state → suggested
-- state" for either a specific agent or a whole team. Human approves
-- (all or per-item) via a diff-review UI; the applier commits the
-- approved subset.
--
-- Proposal payload (JSONB) shape — kept schemaless because proposal
-- kinds evolve. Documented shapes:
--
--   agent proposal:
--     {
--       "kind": "agent",
--       "current": { "system_prompt": "…", "skills": ["…"] },
--       "suggested_items": [
--         { "id": "u1", "kind": "brain_consolidation",
--           "rationale": "…", "brain_md_diff": "…" },
--         { "id": "u2", "kind": "identity_refinement",
---          "rationale": "…", "new_system_prompt": "…" },
--         { "id": "u3", "kind": "skill_add", "skill_id": "…",
--           "rationale": "…" },
--         { "id": "u4", "kind": "skill_candidate",
--           "rationale": "…", "draft": { "name": "…",
--                                        "description": "…",
--                                        "when_to_use": "…",
--                                        "body": "…",
--                                        "tags": ["…"] } }
--       ]
--     }
--
--   team proposal — same shape plus:
--         { "id": "u5", "kind": "roster_change",
--           "op": "add"|"drop"|"rename", "slot": "…", "rationale": "…" }
--         { "id": "u6", "kind": "mcp_bundle_change",
--           "op": "add"|"drop", "bundle": "…", "rationale": "…" }
--
-- `applied_items` is the array of `id`s that the reviewer approved;
-- the applier only touches those.

CREATE TABLE level_up_proposals (
    id            UUID PRIMARY KEY,
    workspace_id  UUID NOT NULL REFERENCES workspaces(id) ON DELETE CASCADE,
    -- Exactly one of these is set; enforced by the CHECK below.
    agent_id      UUID REFERENCES agents(id) ON DELETE CASCADE,
    team_id       UUID REFERENCES teams(id) ON DELETE CASCADE,
    -- 'pending' | 'applied' | 'rejected' | 'partial' (applied a subset)
    status        TEXT NOT NULL DEFAULT 'pending',
    -- Full proposal JSONB (see header comment for shape).
    payload       JSONB NOT NULL,
    -- Ids from payload.suggested_items[] that reviewer approved.
    applied_items TEXT[] NOT NULL DEFAULT '{}',
    -- Model used for the LLM analysis pass (audit trail).
    model         TEXT,
    created_by    UUID REFERENCES users(id) ON DELETE SET NULL,
    approved_by   UUID REFERENCES users(id) ON DELETE SET NULL,
    created_at    TIMESTAMPTZ NOT NULL DEFAULT now(),
    applied_at    TIMESTAMPTZ,
    CONSTRAINT level_up_target_one CHECK (
        (agent_id IS NOT NULL AND team_id IS NULL) OR
        (agent_id IS NULL AND team_id IS NOT NULL)
    )
);

CREATE INDEX level_up_workspace_idx
    ON level_up_proposals (workspace_id, created_at DESC);
CREATE INDEX level_up_pending_idx
    ON level_up_proposals (status, created_at DESC)
    WHERE status = 'pending';
CREATE INDEX level_up_agent_idx
    ON level_up_proposals (agent_id, created_at DESC)
    WHERE agent_id IS NOT NULL;
CREATE INDEX level_up_team_idx
    ON level_up_proposals (team_id, created_at DESC)
    WHERE team_id IS NOT NULL;