-- ==========================================
-- Migration 009: Folders & Projects
-- ==========================================
-- Organizational structures for channels.
-- Folders are simple containers; projects are
-- tagged collections that can span folders.
-- ==========================================

-- ── Folders ─────────────────────────────────

CREATE TABLE IF NOT EXISTS folders (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    name VARCHAR(200) NOT NULL,
    parent_id UUID REFERENCES folders(id) ON DELETE CASCADE,
    sort_order INT DEFAULT 0,
    created_at TIMESTAMPTZ DEFAULT NOW(),
    updated_at TIMESTAMPTZ DEFAULT NOW(),
    UNIQUE(user_id, name, parent_id)
);

CREATE INDEX idx_folders_user ON folders(user_id);
CREATE INDEX idx_folders_parent ON folders(parent_id);

CREATE TRIGGER folders_updated_at BEFORE UPDATE ON folders
    FOR EACH ROW EXECUTE FUNCTION update_updated_at();

-- Add folder_id to channels (replaces the old text folder column)
ALTER TABLE channels ADD COLUMN IF NOT EXISTS folder_id UUID REFERENCES folders(id) ON DELETE SET NULL;
CREATE INDEX IF NOT EXISTS idx_channels_folder ON channels(folder_id);

-- ── Projects ────────────────────────────────

CREATE TABLE IF NOT EXISTS projects (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    name VARCHAR(200) NOT NULL,
    description TEXT,
    color VARCHAR(7),   -- hex color for UI badge
    created_at TIMESTAMPTZ DEFAULT NOW(),
    updated_at TIMESTAMPTZ DEFAULT NOW()
);

CREATE INDEX idx_projects_user ON projects(user_id);

CREATE TRIGGER projects_updated_at BEFORE UPDATE ON projects
    FOR EACH ROW EXECUTE FUNCTION update_updated_at();

-- Junction: channels can belong to multiple projects
CREATE TABLE IF NOT EXISTS project_channels (
    project_id UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
    channel_id UUID NOT NULL REFERENCES channels(id) ON DELETE CASCADE,
    added_at TIMESTAMPTZ DEFAULT NOW(),
    PRIMARY KEY (project_id, channel_id)
);

CREATE INDEX idx_project_channels_channel ON project_channels(channel_id);