-- V16: Cross-Device Sync System
-- Adds device registration, change tracking, and chunked upload support

-- Sync devices table
CREATE TABLE sync_devices (
    id TEXT PRIMARY KEY NOT NULL,
    user_id TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    name TEXT NOT NULL,
    device_type TEXT NOT NULL,
    client_version TEXT NOT NULL,
    os_info TEXT,
    device_token_hash TEXT NOT NULL UNIQUE,
    last_sync_at TIMESTAMPTZ,
    last_seen_at TIMESTAMPTZ NOT NULL,
    sync_cursor BIGINT DEFAULT 0,
    enabled BOOLEAN NOT NULL DEFAULT TRUE,
    created_at TIMESTAMPTZ NOT NULL,
    updated_at TIMESTAMPTZ NOT NULL
);

CREATE INDEX idx_sync_devices_user ON sync_devices(user_id);
CREATE INDEX idx_sync_devices_token ON sync_devices(device_token_hash);

-- Sync log table - tracks all changes for sync
CREATE TABLE sync_log (
    id TEXT PRIMARY KEY NOT NULL,
    sequence BIGSERIAL UNIQUE NOT NULL,
    change_type TEXT NOT NULL,
    media_id TEXT REFERENCES media_items(id) ON DELETE SET NULL,
    path TEXT NOT NULL,
    content_hash TEXT,
    file_size BIGINT,
    metadata_json TEXT,
    changed_by_device TEXT REFERENCES sync_devices(id) ON DELETE SET NULL,
    timestamp TIMESTAMPTZ NOT NULL
);

CREATE INDEX idx_sync_log_sequence ON sync_log(sequence);
CREATE INDEX idx_sync_log_path ON sync_log(path);
CREATE INDEX idx_sync_log_timestamp ON sync_log(timestamp);

-- Device sync state - tracks sync status per device per file
CREATE TABLE device_sync_state (
    device_id TEXT NOT NULL REFERENCES sync_devices(id) ON DELETE CASCADE,
    path TEXT NOT NULL,
    local_hash TEXT,
    server_hash TEXT,
    local_mtime BIGINT,
    server_mtime BIGINT,
    sync_status TEXT NOT NULL,
    last_synced_at TIMESTAMPTZ,
    conflict_info_json TEXT,
    PRIMARY KEY (device_id, path)
);

CREATE INDEX idx_device_sync_status ON device_sync_state(device_id, sync_status);

-- Upload sessions for chunked uploads
CREATE TABLE upload_sessions (
    id TEXT PRIMARY KEY NOT NULL,
    device_id TEXT NOT NULL REFERENCES sync_devices(id) ON DELETE CASCADE,
    target_path TEXT NOT NULL,
    expected_hash TEXT NOT NULL,
    expected_size BIGINT NOT NULL,
    chunk_size BIGINT NOT NULL,
    chunk_count BIGINT NOT NULL,
    status TEXT NOT NULL,
    created_at TIMESTAMPTZ NOT NULL,
    expires_at TIMESTAMPTZ NOT NULL,
    last_activity TIMESTAMPTZ NOT NULL
);

CREATE INDEX idx_upload_sessions_device ON upload_sessions(device_id);
CREATE INDEX idx_upload_sessions_status ON upload_sessions(status);
CREATE INDEX idx_upload_sessions_expires ON upload_sessions(expires_at);

-- Upload chunks - tracks received chunks
CREATE TABLE upload_chunks (
    upload_id TEXT NOT NULL REFERENCES upload_sessions(id) ON DELETE CASCADE,
    chunk_index BIGINT NOT NULL,
    offset BIGINT NOT NULL,
    size BIGINT NOT NULL,
    hash TEXT NOT NULL,
    received_at TIMESTAMPTZ NOT NULL,
    PRIMARY KEY (upload_id, chunk_index)
);

-- Sync conflicts
CREATE TABLE sync_conflicts (
    id TEXT PRIMARY KEY NOT NULL,
    device_id TEXT NOT NULL REFERENCES sync_devices(id) ON DELETE CASCADE,
    path TEXT NOT NULL,
    local_hash TEXT NOT NULL,
    local_mtime BIGINT NOT NULL,
    server_hash TEXT NOT NULL,
    server_mtime BIGINT NOT NULL,
    detected_at TIMESTAMPTZ NOT NULL,
    resolved_at TIMESTAMPTZ,
    resolution TEXT
);

CREATE INDEX idx_sync_conflicts_device ON sync_conflicts(device_id);
CREATE INDEX idx_sync_conflicts_unresolved ON sync_conflicts(device_id) WHERE resolved_at IS NULL;