CREATE TABLE IF NOT EXISTS projects (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  name TEXT NOT NULL,
  path TEXT NOT NULL UNIQUE,
  added_at TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp(),
  last_session_id UUID
);

CREATE TABLE IF NOT EXISTS sessions (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  project_id UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
  name TEXT NOT NULL,
  model TEXT NOT NULL,
  system_prompt TEXT NOT NULL DEFAULT '',
  created_at TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp(),
  updated_at TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp()
);

CREATE INDEX IF NOT EXISTS idx_sessions_project ON sessions(project_id, updated_at DESC);

CREATE TABLE IF NOT EXISTS messages (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  session_id UUID NOT NULL REFERENCES sessions(id) ON DELETE CASCADE,
  role TEXT NOT NULL,
  content TEXT NOT NULL DEFAULT '',
  tool_calls JSONB,
  tool_results JSONB,
  status TEXT NOT NULL DEFAULT 'complete',
  last_seq INT NOT NULL DEFAULT 0,
  created_at TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp()
);

CREATE INDEX IF NOT EXISTS idx_messages_session ON messages(session_id, created_at);

ALTER TABLE messages ADD COLUMN IF NOT EXISTS tokens_used INTEGER;
ALTER TABLE messages ADD COLUMN IF NOT EXISTS ctx_used INTEGER;
ALTER TABLE messages ADD COLUMN IF NOT EXISTS ctx_max INTEGER;
ALTER TABLE messages ADD COLUMN IF NOT EXISTS started_at TIMESTAMPTZ;
ALTER TABLE messages ADD COLUMN IF NOT EXISTS finished_at TIMESTAMPTZ;

ALTER TABLE sessions ADD COLUMN IF NOT EXISTS updated_at TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp();

CREATE TABLE IF NOT EXISTS settings (
  key TEXT PRIMARY KEY,
  value JSONB NOT NULL
);

INSERT INTO settings (key, value) VALUES ('default_model', '"qwen3.6-35b-a3b-mxfp4"') ON CONFLICT (key) DO NOTHING;

-- DEPRECATED: client-side pane state as of v1.2-batch4. Table retained per
-- additive schema rule; no writes. Drop in a future destructive migration.
CREATE TABLE IF NOT EXISTS session_panes (
  id           UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  session_id   UUID NOT NULL REFERENCES sessions(id) ON DELETE CASCADE,
  position     INTEGER NOT NULL,
  kind         TEXT NOT NULL CHECK (kind IN ('chat', 'file_browser')),
  state        JSONB NOT NULL DEFAULT '{}',
  created_at   TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp(),
  UNIQUE (session_id, position)
);
CREATE INDEX IF NOT EXISTS idx_session_panes_session ON session_panes (session_id);

-- v1.4: backfill removed. Pane layout is client-side (localStorage) since v1.2-batch4.
-- The CREATE TABLE above is retained for additive-schema discipline; drop is a
-- future destructive migration.

-- v1.2: sessions.status (open | archived)
ALTER TABLE sessions ADD COLUMN IF NOT EXISTS status TEXT NOT NULL DEFAULT 'open';

-- v1.2: chats table
CREATE TABLE IF NOT EXISTS chats (
  id           UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  session_id   UUID NOT NULL REFERENCES sessions(id) ON DELETE CASCADE,
  name         TEXT,
  status       TEXT NOT NULL DEFAULT 'open' CHECK (status IN ('open', 'archived')),
  created_at   TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp(),
  updated_at   TIMESTAMPTZ NOT NULL DEFAULT clock_timestamp()
);
CREATE INDEX IF NOT EXISTS idx_chats_session_status ON chats (session_id, status, updated_at DESC);

-- v1.2: messages.chat_id + messages.kind
ALTER TABLE messages ADD COLUMN IF NOT EXISTS chat_id UUID REFERENCES chats(id) ON DELETE CASCADE;
ALTER TABLE messages ADD COLUMN IF NOT EXISTS kind TEXT NOT NULL DEFAULT 'message';
CREATE INDEX IF NOT EXISTS idx_messages_chat ON messages (chat_id, created_at);

-- Backfill: one chat per existing session that has none yet
INSERT INTO chats (session_id, name, status, created_at, updated_at)
SELECT s.id, s.name, 'open', s.created_at, s.updated_at
FROM sessions s
WHERE NOT EXISTS (
  SELECT 1 FROM chats c WHERE c.session_id = s.id
);

-- Backfill: link orphaned messages to their session's first chat
UPDATE messages SET chat_id = (
  SELECT c.id FROM chats c WHERE c.session_id = messages.session_id ORDER BY c.created_at ASC LIMIT 1
)
WHERE chat_id IS NULL;

-- Enforce NOT NULL on chat_id once all rows are backfilled
DO $$
BEGIN
  IF EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'messages' AND column_name = 'chat_id' AND is_nullable = 'YES'
  ) AND NOT EXISTS (
    SELECT 1 FROM messages WHERE chat_id IS NULL
  ) THEN
    ALTER TABLE messages ALTER COLUMN chat_id SET NOT NULL;
  END IF;
END $$;

-- v1.2.1: CHECK constraints for sessions.status and messages (role, status)
-- KEEP IN SYNC: apps/server/src/types/api.ts (MESSAGE_ROLES, MESSAGE_STATUSES, SessionStatus)
DO $$
BEGIN
  IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'sessions_status_chk') THEN
    ALTER TABLE sessions ADD CONSTRAINT sessions_status_chk
      CHECK (status IN ('open', 'archived'));
  END IF;
  IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'messages_role_chk') THEN
    ALTER TABLE messages ADD CONSTRAINT messages_role_chk
      CHECK (role IN ('user', 'assistant', 'system', 'tool'));
  END IF;
  IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'messages_status_chk') THEN
    ALTER TABLE messages ADD CONSTRAINT messages_status_chk
      CHECK (status IN ('streaming', 'complete', 'failed', 'cancelled'));
  END IF;
END $$;

-- v1.2-project-ux: projects.status + projects.gitea_remote
-- KEEP IN SYNC: apps/server/src/types/api.ts PROJECT_STATUSES
ALTER TABLE projects ADD COLUMN IF NOT EXISTS status TEXT NOT NULL DEFAULT 'open';
ALTER TABLE projects ADD COLUMN IF NOT EXISTS gitea_remote TEXT;
DO $$
BEGIN
  IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'projects_status_chk') THEN
    ALTER TABLE projects ADD CONSTRAINT projects_status_chk
      CHECK (status IN ('open', 'archived'));
  END IF;
END $$;

-- v1.3-tab-close-chat-archive: align chats.status vocabulary with projects ('archived' not 'closed')
-- KEEP IN SYNC: apps/server/src/types/api.ts CHAT_STATUSES
-- Order matters: (1) drop the OLD inline CHECK that only allowed ('open','closed');
-- (2) migrate existing rows; (3) add new named CHECK allowing ('open','archived').
ALTER TABLE chats DROP CONSTRAINT IF EXISTS chats_status_check;
UPDATE chats SET status = 'archived' WHERE status = 'closed';
DO $$
BEGIN
  IF NOT EXISTS (SELECT 1 FROM pg_constraint WHERE conname = 'chats_status_chk') THEN
    ALTER TABLE chats ADD CONSTRAINT chats_status_chk
      CHECK (status IN ('open', 'archived'));
  END IF;
END $$;