-- Design Thinking Schema for Mylder Platform
-- Migration: 20251214_design_thinking_schema.sql

-- Enable UUID extension
CREATE EXTENSION IF NOT EXISTS "uuid-ossp";

-- Design phases enum
CREATE TYPE design_phase AS ENUM ('empathize', 'define', 'ideate', 'prototype', 'test');
CREATE TYPE phase_status AS ENUM ('not_started', 'in_progress', 'completed', 'blocked', 'needs_review');
CREATE TYPE backlog_status AS ENUM ('backlog', 'ready', 'in_progress', 'done', 'blocked');
CREATE TYPE recommendation_type AS ENUM ('action', 'warning', 'insight', 'optimization');
CREATE TYPE recommendation_priority AS ENUM ('low', 'medium', 'high');

-- Projects table (extend or create)
CREATE TABLE IF NOT EXISTS projects (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
  user_id UUID NOT NULL REFERENCES auth.users(id) ON DELETE CASCADE,
  name TEXT NOT NULL,
  description TEXT,
  current_phase design_phase DEFAULT 'empathize',
  health_score INTEGER DEFAULT 100 CHECK (health_score >= 0 AND health_score <= 100),
  created_at TIMESTAMPTZ DEFAULT NOW(),
  updated_at TIMESTAMPTZ DEFAULT NOW()
);

-- Project phase tracking
CREATE TABLE project_phases (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
  project_id UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
  phase design_phase NOT NULL,
  status phase_status DEFAULT 'not_started',
  started_at TIMESTAMPTZ,
  completed_at TIMESTAMPTZ,
  notes TEXT,
  iteration INTEGER DEFAULT 1,
  created_at TIMESTAMPTZ DEFAULT NOW(),
  updated_at TIMESTAMPTZ DEFAULT NOW(),
  UNIQUE(project_id, phase, iteration)
);

-- Backlog items with WSJF prioritization
CREATE TABLE backlog_items (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
  project_id UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
  title TEXT NOT NULL,
  description TEXT,
  phase design_phase NOT NULL,
  status backlog_status DEFAULT 'backlog',

  -- WSJF scoring (1-10 scale)
  user_value INTEGER DEFAULT 5 CHECK (user_value >= 1 AND user_value <= 10),
  time_criticality INTEGER DEFAULT 5 CHECK (time_criticality >= 1 AND time_criticality <= 10),
  risk_reduction INTEGER DEFAULT 5 CHECK (risk_reduction >= 1 AND risk_reduction <= 10),
  effort INTEGER DEFAULT 5 CHECK (effort >= 1 AND effort <= 10),

  -- Computed priority score: (user_value + time_criticality + risk_reduction) / effort
  priority_score DECIMAL(4,2) GENERATED ALWAYS AS (
    (user_value + time_criticality + risk_reduction)::DECIMAL / GREATEST(effort, 1)
  ) STORED,

  -- Dependencies
  depends_on UUID[] DEFAULT '{}',

  -- Assignment
  assigned_to UUID REFERENCES auth.users(id),
  due_date DATE,

  created_at TIMESTAMPTZ DEFAULT NOW(),
  updated_at TIMESTAMPTZ DEFAULT NOW()
);

-- AI recommendations
CREATE TABLE ai_recommendations (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
  project_id UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
  type recommendation_type NOT NULL,
  priority recommendation_priority DEFAULT 'medium',
  title TEXT NOT NULL,
  description TEXT NOT NULL,
  action_command TEXT,
  related_items UUID[] DEFAULT '{}',
  dismissed BOOLEAN DEFAULT FALSE,
  dismissed_at TIMESTAMPTZ,
  created_at TIMESTAMPTZ DEFAULT NOW()
);

-- Project health metrics (historical tracking)
CREATE TABLE project_health_snapshots (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
  project_id UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
  overall_score INTEGER NOT NULL CHECK (overall_score >= 0 AND overall_score <= 100),
  velocity INTEGER DEFAULT 0,
  blockers INTEGER DEFAULT 0,
  overdue INTEGER DEFAULT 0,
  completion_rate INTEGER DEFAULT 0,
  snapshot_date DATE DEFAULT CURRENT_DATE,
  created_at TIMESTAMPTZ DEFAULT NOW(),
  UNIQUE(project_id, snapshot_date)
);

-- Activity feed for projects
CREATE TABLE project_activities (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
  project_id UUID NOT NULL REFERENCES projects(id) ON DELETE CASCADE,
  user_id UUID REFERENCES auth.users(id),
  activity_type TEXT NOT NULL,
  message TEXT NOT NULL,
  metadata JSONB DEFAULT '{}',
  created_at TIMESTAMPTZ DEFAULT NOW()
);

-- Indexes for performance
CREATE INDEX idx_projects_user_id ON projects(user_id);
CREATE INDEX idx_project_phases_project_id ON project_phases(project_id);
CREATE INDEX idx_backlog_items_project_id ON backlog_items(project_id);
CREATE INDEX idx_backlog_items_status ON backlog_items(status);
CREATE INDEX idx_backlog_items_priority ON backlog_items(priority_score DESC);
CREATE INDEX idx_ai_recommendations_project_id ON ai_recommendations(project_id);
CREATE INDEX idx_ai_recommendations_dismissed ON ai_recommendations(dismissed) WHERE dismissed = FALSE;
CREATE INDEX idx_project_health_snapshots_project_id ON project_health_snapshots(project_id);
CREATE INDEX idx_project_activities_project_id ON project_activities(project_id);
CREATE INDEX idx_project_activities_created_at ON project_activities(created_at DESC);

-- Row Level Security
ALTER TABLE projects ENABLE ROW LEVEL SECURITY;
ALTER TABLE project_phases ENABLE ROW LEVEL SECURITY;
ALTER TABLE backlog_items ENABLE ROW LEVEL SECURITY;
ALTER TABLE ai_recommendations ENABLE ROW LEVEL SECURITY;
ALTER TABLE project_health_snapshots ENABLE ROW LEVEL SECURITY;
ALTER TABLE project_activities ENABLE ROW LEVEL SECURITY;

-- RLS Policies: Users can only access their own projects
CREATE POLICY "Users can view their own projects" ON projects
  FOR SELECT USING (auth.uid() = user_id);

CREATE POLICY "Users can create their own projects" ON projects
  FOR INSERT WITH CHECK (auth.uid() = user_id);

CREATE POLICY "Users can update their own projects" ON projects
  FOR UPDATE USING (auth.uid() = user_id);

CREATE POLICY "Users can delete their own projects" ON projects
  FOR DELETE USING (auth.uid() = user_id);

-- RLS for project_phases
CREATE POLICY "Users can manage phases of their projects" ON project_phases
  FOR ALL USING (
    EXISTS (SELECT 1 FROM projects WHERE projects.id = project_phases.project_id AND projects.user_id = auth.uid())
  );

-- RLS for backlog_items
CREATE POLICY "Users can manage backlog of their projects" ON backlog_items
  FOR ALL USING (
    EXISTS (SELECT 1 FROM projects WHERE projects.id = backlog_items.project_id AND projects.user_id = auth.uid())
  );

-- RLS for ai_recommendations
CREATE POLICY "Users can view recommendations for their projects" ON ai_recommendations
  FOR ALL USING (
    EXISTS (SELECT 1 FROM projects WHERE projects.id = ai_recommendations.project_id AND projects.user_id = auth.uid())
  );

-- RLS for project_health_snapshots
CREATE POLICY "Users can view health of their projects" ON project_health_snapshots
  FOR ALL USING (
    EXISTS (SELECT 1 FROM projects WHERE projects.id = project_health_snapshots.project_id AND projects.user_id = auth.uid())
  );

-- RLS for project_activities
CREATE POLICY "Users can view activities of their projects" ON project_activities
  FOR ALL USING (
    EXISTS (SELECT 1 FROM projects WHERE projects.id = project_activities.project_id AND projects.user_id = auth.uid())
  );

-- Functions

-- Update updated_at timestamp
CREATE OR REPLACE FUNCTION update_updated_at()
RETURNS TRIGGER AS $$
BEGIN
  NEW.updated_at = NOW();
  RETURN NEW;
END;
$$ LANGUAGE plpgsql;

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

CREATE TRIGGER project_phases_updated_at BEFORE UPDATE ON project_phases
  FOR EACH ROW EXECUTE FUNCTION update_updated_at();

CREATE TRIGGER backlog_items_updated_at BEFORE UPDATE ON backlog_items
  FOR EACH ROW EXECUTE FUNCTION update_updated_at();

-- Function to calculate project health
CREATE OR REPLACE FUNCTION calculate_project_health(p_project_id UUID)
RETURNS INTEGER AS $$
DECLARE
  total_items INTEGER;
  done_items INTEGER;
  blocked_items INTEGER;
  overdue_items INTEGER;
  health INTEGER;
BEGIN
  SELECT COUNT(*),
         COUNT(*) FILTER (WHERE status = 'done'),
         COUNT(*) FILTER (WHERE status = 'blocked'),
         COUNT(*) FILTER (WHERE due_date < CURRENT_DATE AND status NOT IN ('done', 'blocked'))
  INTO total_items, done_items, blocked_items, overdue_items
  FROM backlog_items WHERE project_id = p_project_id;

  IF total_items = 0 THEN
    RETURN 100;
  END IF;

  -- Health calculation: base 100, minus penalties
  health := 100;
  health := health - (blocked_items * 10);  -- -10 per blocker
  health := health - (overdue_items * 5);   -- -5 per overdue
  health := health + (done_items * 2);      -- +2 per completed

  RETURN GREATEST(0, LEAST(100, health));
END;
$$ LANGUAGE plpgsql;

-- Function to record daily health snapshot
CREATE OR REPLACE FUNCTION record_health_snapshot(p_project_id UUID)
RETURNS VOID AS $$
DECLARE
  v_health INTEGER;
  v_velocity INTEGER;
  v_blockers INTEGER;
  v_overdue INTEGER;
  v_completion_rate INTEGER;
  v_total INTEGER;
  v_done INTEGER;
BEGIN
  v_health := calculate_project_health(p_project_id);

  SELECT COUNT(*) FILTER (WHERE status = 'blocked'),
         COUNT(*) FILTER (WHERE due_date < CURRENT_DATE AND status NOT IN ('done', 'blocked')),
         COUNT(*),
         COUNT(*) FILTER (WHERE status = 'done')
  INTO v_blockers, v_overdue, v_total, v_done
  FROM backlog_items WHERE project_id = p_project_id;

  v_completion_rate := CASE WHEN v_total > 0 THEN (v_done * 100 / v_total) ELSE 0 END;

  -- Velocity: items completed in last 7 days
  SELECT COUNT(*) INTO v_velocity
  FROM backlog_items
  WHERE project_id = p_project_id
    AND status = 'done'
    AND updated_at >= NOW() - INTERVAL '7 days';

  INSERT INTO project_health_snapshots (project_id, overall_score, velocity, blockers, overdue, completion_rate)
  VALUES (p_project_id, v_health, v_velocity, v_blockers, v_overdue, v_completion_rate)
  ON CONFLICT (project_id, snapshot_date)
  DO UPDATE SET
    overall_score = EXCLUDED.overall_score,
    velocity = EXCLUDED.velocity,
    blockers = EXCLUDED.blockers,
    overdue = EXCLUDED.overdue,
    completion_rate = EXCLUDED.completion_rate;

  -- Update project health_score
  UPDATE projects SET health_score = v_health WHERE id = p_project_id;
END;
$$ LANGUAGE plpgsql;

-- Comments for documentation
COMMENT ON TABLE projects IS 'User projects with design thinking phases';
COMMENT ON TABLE project_phases IS 'Track status of each design phase per project iteration';
COMMENT ON TABLE backlog_items IS 'Prioritized backlog with WSJF scoring';
COMMENT ON COLUMN backlog_items.priority_score IS 'WSJF: (user_value + time_criticality + risk_reduction) / effort';
COMMENT ON TABLE ai_recommendations IS 'AI-generated insights and action recommendations';
COMMENT ON TABLE project_health_snapshots IS 'Daily snapshots of project health metrics';