-- -*- mode: sql; sql-product: sqlite; -*-

-- This file defines the odidere database schema.
--
-- Conversations contain messages stored as individual rows. Each
-- message stores its wire-format JSON in the content column, matching
-- the OpenAI Chat Completions API message structure. This avoids
-- per-part decomposition while keeping messages individually addressable
-- for editing, deletion, and branching.
--
-- Timestamps are stored as TEXT in RFC3339 format. Tables use STRICT typing.

-- Users are authenticated accounts. The name is the login identifier,
-- unique case-insensitively. The role column is constrained to a fixed set;
-- at this time only the "owner" role is supported.
-- Deleting a user cascades to all their sessions and conversations.
CREATE TABLE IF NOT EXISTS users (
    created_at     TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
    deactivated_at TEXT,
    id             TEXT PRIMARY KEY,
    name           TEXT NOT NULL UNIQUE COLLATE NOCASE,
    password       TEXT NOT NULL,
    role           TEXT NOT NULL,
    updated_at     TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
    CHECK (role IN ('owner'))
) STRICT;

CREATE INDEX IF NOT EXISTS idx_users_deactivated ON users(deactivated_at);

-- Sessions represent authenticated login sessions. The session id is used
-- as the bearer token in HTTP requests.
CREATE TABLE IF NOT EXISTS sessions (
    created_at     TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
    deactivated_at TEXT,
    id             TEXT PRIMARY KEY,
    updated_at     TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
    user_id        TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE
) STRICT;

CREATE INDEX IF NOT EXISTS idx_sessions_active ON sessions(user_id, created_at) WHERE deactivated_at IS NULL;

-- Conversations are top-level containers for message threads. Each
-- conversation belongs to a single user. Deleting a conversation
-- cascades to all its messages.
CREATE TABLE IF NOT EXISTS conversations (
    created_at  TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
    id          TEXT PRIMARY KEY,
    title       TEXT,
    updated_at  TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
    user_id     TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE
) STRICT;

CREATE INDEX IF NOT EXISTS idx_conv_user ON conversations(user_id);

-- Messages are ordered entries within a conversation. The content column
-- stores the wire-format JSON for the message — the exact JSON object
-- that appears in the OpenAI Chat Completions messages array. The role
-- column is extracted for querying without JSON parsing. Nullable metadata
-- stores inference JSONB separately from model-visible content. The sequence
-- column defines ordering within the conversation. Deleting a message
-- cascades to nothing further (all message data is in the row).
CREATE TABLE IF NOT EXISTS messages (
    conversation_id TEXT NOT NULL REFERENCES conversations(id) ON DELETE CASCADE,
    content         TEXT NOT NULL,
    created_at      TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
    id              TEXT PRIMARY KEY,
    metadata        BLOB CHECK (metadata IS NULL OR json_valid(metadata, 8)),
    role            TEXT NOT NULL,
    sequence        INTEGER NOT NULL,
    updated_at      TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
    CHECK (role IN ('system', 'developer', 'user', 'assistant', 'tool')),
    UNIQUE(conversation_id, sequence)
) STRICT;

CREATE INDEX IF NOT EXISTS idx_msg_conv ON messages(conversation_id);
CREATE INDEX IF NOT EXISTS idx_msg_conv_seq ON messages(conversation_id, sequence);

-- A conversation's timestamp is its synchronization token.
-- Keep it current whenever the conversation message set changes.
CREATE TRIGGER IF NOT EXISTS messages_insert_conversation_updated_at
AFTER INSERT ON messages
BEGIN
    UPDATE conversations
    SET updated_at = strftime('%Y-%m-%dT%H:%M:%fZ', 'now')
    WHERE id = NEW.conversation_id;
END;

CREATE TRIGGER IF NOT EXISTS messages_update_conversation_updated_at
AFTER UPDATE ON messages
BEGIN
    UPDATE conversations
    SET updated_at = strftime('%Y-%m-%dT%H:%M:%fZ', 'now')
    WHERE id = NEW.conversation_id;
END;

CREATE TRIGGER IF NOT EXISTS messages_delete_conversation_updated_at
AFTER DELETE ON messages
BEGIN
    UPDATE conversations
    SET updated_at = strftime('%Y-%m-%dT%H:%M:%fZ', 'now')
    WHERE id = OLD.conversation_id;
END;

-- Executions track the state of tool calls. Each row references a
-- specific tool call within an assistant message via message_id and
-- tool_call_id. The tool call's name and arguments are stored in the
-- message's content JSON; they are not duplicated here. The tool's
-- execution result (stdout, stderr, exit code) is stored as a
-- separate tool-role message in the messages table, not in this row.
--
-- Lifecycle, by tool kind:
--
-- A. Approval not required:
--
-- ┌────────────┐    ┌────────────┐
-- │  running   ├┄┄┄▶│ completed  │
-- └────────────┘    └────────────┘
--
-- B. Approval required:
--
-- ┌────────────┐    ┌────────────┐    ┌────────────┐    ┌────────────┐
-- │  pending   ├───▶│  approved  ├───▶│  running   ├┄┄┄▶│ completed  │
-- └────────────┘    └────────────┘    └────────────┘    └────────────┘
--       │
--       ▼
-- ┌────────────┐
-- │   denied   │
-- └────────────┘
--
-- The dashed arrow from running to completed indicates the possibility that a
-- tool call may not complete. if a tool call is interrupted, the row ends at
-- running.
--
-- approved:  tool call approved by user. The call has not launched yet.
-- completed: the tool call returned output or an error. Terminal.
-- denied:    user refused the tool call. Terminal.
-- pending:   the call awaits a user decision.
-- running:   the tool call either:
--            A. is about to be started,
--            B. was started and is still executing,
--            C. was interrupted before it started or finished (terminal).
CREATE TABLE IF NOT EXISTS executions (
    created_at   TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
    id           TEXT PRIMARY KEY,
    message_id   TEXT NOT NULL REFERENCES messages(id) ON DELETE CASCADE,
    status       TEXT NOT NULL DEFAULT 'running',
    tool_call_id TEXT NOT NULL,
    updated_at   TEXT NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%fZ', 'now')),
    CHECK (status IN ('approved', 'completed', 'denied', 'pending', 'running'))
) STRICT;

CREATE INDEX IF NOT EXISTS idx_executions_message ON executions(message_id);
CREATE INDEX IF NOT EXISTS idx_executions_pending ON executions(status) WHERE status = 'pending';
-- Prevent duplicate execution rows for the same tool call in a message.
CREATE UNIQUE INDEX IF NOT EXISTS idx_executions_call ON executions(message_id, tool_call_id);

-- Default user. Temporary workaround until authentication is built.
INSERT INTO users (id, name, password, role)
VALUES ('default', 'owner', '', 'owner');