-- TekDek Command Center Database Schema
-- PostgreSQL 13+
-- Created for precise project and task management

-- ============================================================================
-- USERS TABLE
-- ============================================================================
CREATE TABLE IF NOT EXISTS users (
  id BIGSERIAL PRIMARY KEY,
  username VARCHAR(100) NOT NULL UNIQUE,
  email VARCHAR(255) NOT NULL UNIQUE,
  display_name VARCHAR(255),
  password_hash VARCHAR(255),
  role VARCHAR(50) NOT NULL DEFAULT 'user',
  is_active BOOLEAN DEFAULT TRUE,
  created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
  updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
  
  CONSTRAINT role_check CHECK (role IN ('admin', 'user'))
);

CREATE INDEX IF NOT EXISTS idx_users_username ON users(username);
CREATE INDEX IF NOT EXISTS idx_users_email ON users(email);
CREATE INDEX IF NOT EXISTS idx_users_is_active ON users(is_active);

-- ============================================================================
-- PROJECTS TABLE
-- ============================================================================
CREATE TABLE IF NOT EXISTS projects (
  id BIGSERIAL PRIMARY KEY,
  name VARCHAR(255) NOT NULL,
  description TEXT,
  status VARCHAR(50) NOT NULL DEFAULT 'active',
  color_hex VARCHAR(7) DEFAULT '#3498db',
  icon_name VARCHAR(50),
  owner_id BIGINT NOT NULL,
  created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
  updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
  
  CONSTRAINT status_check CHECK (status IN ('active', 'archived', 'paused')),
  CONSTRAINT color_format CHECK (color_hex ~ '^#[0-9a-fA-F]{6}$'),
  CONSTRAINT fk_owner 
    FOREIGN KEY (owner_id) 
    REFERENCES users(id) 
    ON DELETE RESTRICT
);

CREATE INDEX IF NOT EXISTS idx_projects_owner_id ON projects(owner_id);
CREATE INDEX IF NOT EXISTS idx_projects_status ON projects(status);
CREATE INDEX IF NOT EXISTS idx_projects_updated_at ON projects(updated_at DESC);

-- ============================================================================
-- TASKS TABLE
-- ============================================================================
CREATE TABLE IF NOT EXISTS tasks (
  id BIGSERIAL PRIMARY KEY,
  project_id BIGINT NOT NULL,
  title VARCHAR(500) NOT NULL,
  description TEXT,
  status VARCHAR(50) NOT NULL DEFAULT 'backlog',
  position INTEGER NOT NULL,
  due_date DATE,
  assignee_id BIGINT,
  created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
  updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
  created_by BIGINT NOT NULL,
  
  CONSTRAINT fk_project 
    FOREIGN KEY (project_id) 
    REFERENCES projects(id) 
    ON DELETE CASCADE,
  CONSTRAINT fk_assignee 
    FOREIGN KEY (assignee_id) 
    REFERENCES users(id) 
    ON DELETE SET NULL,
  CONSTRAINT fk_created_by 
    FOREIGN KEY (created_by) 
    REFERENCES users(id) 
    ON DELETE RESTRICT,
  CONSTRAINT status_check CHECK (status IN ('backlog', 'in_progress', 'done', 'blocked')),
  CONSTRAINT position_check CHECK (position >= 0)
);

CREATE INDEX IF NOT EXISTS idx_tasks_project_id ON tasks(project_id);
CREATE INDEX IF NOT EXISTS idx_tasks_status ON tasks(status);
CREATE INDEX IF NOT EXISTS idx_tasks_project_status ON tasks(project_id, status);
CREATE INDEX IF NOT EXISTS idx_tasks_position ON tasks(project_id, position);
CREATE INDEX IF NOT EXISTS idx_tasks_assignee_id ON tasks(assignee_id);
CREATE INDEX IF NOT EXISTS idx_tasks_due_date ON tasks(due_date);
CREATE INDEX IF NOT EXISTS idx_tasks_updated_at ON tasks(updated_at DESC);

-- ============================================================================
-- SEED DATA (Initial users)
-- ============================================================================
INSERT INTO users (username, email, display_name, role, is_active)
VALUES 
  ('parzivaltd', 'parzival@tekdek.dev', 'ParzivalTD', 'admin', TRUE),
  ('glytcht', 'glytcht@tekdek.dev', 'Glytcht', 'admin', TRUE)
ON CONFLICT (username) DO NOTHING;