-- 科研智能体会话与消息持久化表
-- 支持 ReAct 框架的多轮对话、工具调用与思考链存储

CREATE TABLE IF NOT EXISTS agent_sessions (
    session_id TEXT PRIMARY KEY,
    title TEXT NOT NULL DEFAULT '',
    model TEXT NOT NULL DEFAULT '',
    turn_count INTEGER NOT NULL DEFAULT 0,
    last_error TEXT,
    summary TEXT,
    metadata TEXT,
    created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
    updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
    deleted_at DATETIME
);

CREATE TABLE IF NOT EXISTS agent_messages (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    session_id TEXT NOT NULL,
    turn_index INTEGER NOT NULL DEFAULT 0,
    step_index INTEGER NOT NULL DEFAULT 0,
    role TEXT NOT NULL CHECK(role IN ('system', 'user', 'assistant', 'tool')),
    content TEXT NOT NULL DEFAULT '',
    thought TEXT,
    tool_calls TEXT,
    tool_call_id TEXT,
    token_count INTEGER NOT NULL DEFAULT 0,
    metadata TEXT,
    raw_json TEXT,
    created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (session_id) REFERENCES agent_sessions(session_id) ON DELETE CASCADE
);

CREATE INDEX IF NOT EXISTS idx_agent_messages_session ON agent_messages(session_id);
CREATE INDEX IF NOT EXISTS idx_agent_messages_turn ON agent_messages(session_id, turn_index);
CREATE INDEX IF NOT EXISTS idx_agent_sessions_updated ON agent_sessions(updated_at) WHERE deleted_at IS NULL;