-- Create tasks table
CREATE TABLE IF NOT EXISTS tasks (
  id UUID DEFAULT uuid_generate_v4() PRIMARY KEY,
  kr_id UUID NOT NULL REFERENCES krs(id) ON DELETE CASCADE,
  title TEXT NOT NULL,
  description TEXT, -- 思路
  status TEXT NOT NULL DEFAULT 'todo', -- todo, in_progress, expected, done
  priority INTEGER DEFAULT 50, -- 重要级 0-100
  urgency INTEGER DEFAULT 50, -- 紧急程度 0-100
  owner_user_id UUID REFERENCES users(id), -- 负责人
  executor_ids UUID[] DEFAULT '{}', -- 执行人列表
  start_date DATE,
  end_date DATE,
  created_at TIMESTAMP WITH TIME ZONE DEFAULT timezone('utc'::text, now()) NOT NULL,
  updated_at TIMESTAMP WITH TIME ZONE DEFAULT timezone('utc'::text, now()) NOT NULL
);

-- Create task_steps table
CREATE TABLE IF NOT EXISTS task_steps (
  id UUID DEFAULT uuid_generate_v4() PRIMARY KEY,
  task_id UUID NOT NULL REFERENCES tasks(id) ON DELETE CASCADE,
  content TEXT NOT NULL,
  note TEXT,
  executor_id UUID REFERENCES users(id),
  start_date DATE,
  end_date DATE,
  is_completed BOOLEAN DEFAULT FALSE,
  created_at TIMESTAMP WITH TIME ZONE DEFAULT timezone('utc'::text, now()) NOT NULL
);

-- Add indexes
CREATE INDEX IF NOT EXISTS idx_tasks_kr_id ON tasks(kr_id);
CREATE INDEX IF NOT EXISTS idx_task_steps_task_id ON task_steps(task_id);

-- Enable RLS
ALTER TABLE tasks ENABLE ROW LEVEL SECURITY;
ALTER TABLE task_steps ENABLE ROW LEVEL SECURITY;

-- RLS Policies for tasks
CREATE POLICY "Users can view tasks of visible KRs" ON tasks
  FOR SELECT USING (
    EXISTS (
      SELECT 1 FROM krs 
      WHERE krs.id = tasks.kr_id 
      AND (
        -- KR visibility logic (simplified for now: if you can see the project, you can see the KR)
        EXISTS (
            SELECT 1 FROM projects WHERE projects.id = krs.project_id
        )
      )
    )
  );

CREATE POLICY "Users can insert tasks" ON tasks
  FOR INSERT WITH CHECK (true); -- Allow all authenticated users to create tasks for now

CREATE POLICY "Users can update tasks" ON tasks
  FOR UPDATE USING (true);

CREATE POLICY "Users can delete tasks" ON tasks
  FOR DELETE USING (true);

-- RLS Policies for task_steps
CREATE POLICY "Users can view steps" ON task_steps FOR SELECT USING (true);
CREATE POLICY "Users can insert steps" ON task_steps FOR INSERT WITH CHECK (true);
CREATE POLICY "Users can update steps" ON task_steps FOR UPDATE USING (true);
CREATE POLICY "Users can delete steps" ON task_steps FOR DELETE USING (true);