CREATE TABLE "agent_sessions" (
    "id" UUID NOT NULL,
    "course_id" UUID NOT NULL,
    "week_id" UUID,
    "student_id" UUID NOT NULL,
    "status" TEXT NOT NULL DEFAULT 'ACTIVE',
    "title" TEXT,
    "created_at" TIMESTAMPTZ(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updated_at" TIMESTAMPTZ(3) NOT NULL,
    "last_activity_at" TIMESTAMPTZ(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    CONSTRAINT "agent_sessions_pkey" PRIMARY KEY ("id")
);

CREATE TABLE "agent_messages" (
    "id" UUID NOT NULL,
    "session_id" UUID NOT NULL,
    "client_message_id" TEXT NOT NULL,
    "role" TEXT NOT NULL,
    "content" TEXT NOT NULL,
    "provider" TEXT,
    "model" TEXT,
    "summary" TEXT,
    "explanation" TEXT,
    "action_plan" JSONB,
    "create_module" JSONB,
    "apply_state" TEXT,
    "apply_error" TEXT,
    "usage" JSONB,
    "created_at" TIMESTAMPTZ(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updated_at" TIMESTAMPTZ(3) NOT NULL,
    CONSTRAINT "agent_messages_pkey" PRIMARY KEY ("id")
);

CREATE TABLE "agent_actions" (
    "id" UUID NOT NULL,
    "message_id" UUID NOT NULL,
    "client_key" TEXT NOT NULL,
    "type" TEXT NOT NULL,
    "status" TEXT NOT NULL,
    "module_name" TEXT,
    "path" TEXT,
    "command" TEXT,
    "purpose" TEXT,
    "reason" TEXT,
    "content" TEXT,
    "output" TEXT,
    "exit_code" INTEGER,
    "error" TEXT,
    "payload" JSONB,
    "sort_order" INTEGER NOT NULL DEFAULT 0,
    "created_at" TIMESTAMPTZ(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
    "updated_at" TIMESTAMPTZ(3) NOT NULL,
    CONSTRAINT "agent_actions_pkey" PRIMARY KEY ("id")
);

CREATE INDEX "agent_sessions_student_id_course_id_week_id_status_last_activity_at_idx" ON "agent_sessions"("student_id", "course_id", "week_id", "status", "last_activity_at");
CREATE INDEX "agent_sessions_course_id_last_activity_at_idx" ON "agent_sessions"("course_id", "last_activity_at");
CREATE UNIQUE INDEX "agent_messages_session_id_client_message_id_key" ON "agent_messages"("session_id", "client_message_id");
CREATE INDEX "agent_messages_session_id_created_at_idx" ON "agent_messages"("session_id", "created_at");
CREATE UNIQUE INDEX "agent_actions_message_id_client_key_key" ON "agent_actions"("message_id", "client_key");
CREATE INDEX "agent_actions_message_id_sort_order_idx" ON "agent_actions"("message_id", "sort_order");
CREATE INDEX "agent_actions_type_status_created_at_idx" ON "agent_actions"("type", "status", "created_at");

ALTER TABLE "agent_sessions" ADD CONSTRAINT "agent_sessions_course_id_fkey" FOREIGN KEY ("course_id") REFERENCES "courses"("id") ON DELETE CASCADE ON UPDATE CASCADE;
ALTER TABLE "agent_sessions" ADD CONSTRAINT "agent_sessions_week_id_fkey" FOREIGN KEY ("week_id") REFERENCES "course_weeks"("id") ON DELETE SET NULL ON UPDATE CASCADE;
ALTER TABLE "agent_sessions" ADD CONSTRAINT "agent_sessions_student_id_fkey" FOREIGN KEY ("student_id") REFERENCES "users"("id") ON DELETE CASCADE ON UPDATE CASCADE;
ALTER TABLE "agent_messages" ADD CONSTRAINT "agent_messages_session_id_fkey" FOREIGN KEY ("session_id") REFERENCES "agent_sessions"("id") ON DELETE CASCADE ON UPDATE CASCADE;
ALTER TABLE "agent_actions" ADD CONSTRAINT "agent_actions_message_id_fkey" FOREIGN KEY ("message_id") REFERENCES "agent_messages"("id") ON DELETE CASCADE ON UPDATE CASCADE;