-- Enable UUID extension for secure user identification
CREATE EXTENSION IF NOT EXISTS "uuid-ossp";

-- Create enum for skill levels
CREATE TYPE skill_level_enum AS ENUM ('never', 'not-autonomous', 'autonomous', 'expert');

-- Teams table
CREATE TABLE teams (
    id VARCHAR(50) PRIMARY KEY,
    name VARCHAR(100) NOT NULL,
    direction VARCHAR(100) NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Skill categories table
CREATE TABLE skill_categories (
    id VARCHAR(50) PRIMARY KEY,
    name VARCHAR(100) NOT NULL,
    icon VARCHAR(100) NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Skills table
CREATE TABLE skills (
    id VARCHAR(100) PRIMARY KEY,
    name VARCHAR(200) NOT NULL,
    description TEXT,
    icon VARCHAR(100),
    category_id VARCHAR(50) REFERENCES skill_categories(id),
    importance VARCHAR(20) DEFAULT 'standard' CHECK (importance IN ('incontournable', 'majeure', 'standard')),
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Skill links table
CREATE TABLE skill_links (
    id SERIAL PRIMARY KEY,
    skill_id VARCHAR(100) REFERENCES skills(id) ON DELETE CASCADE,
    url TEXT NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Users table with UUID primary key for security
-- UUIDs prevent user enumeration attacks (vs sequential IDs 1,2,3...)
CREATE TABLE users (
    id SERIAL, -- Legacy ID kept for backward compatibility during migration
    uuid_id UUID DEFAULT uuid_generate_v4() NOT NULL,
    first_name VARCHAR(100) NOT NULL,
    last_name VARCHAR(100) NOT NULL,
    team_id VARCHAR(50) REFERENCES teams(id),
    email VARCHAR(255) UNIQUE NOT NULL,
    password_hash VARCHAR(255) NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    PRIMARY KEY (uuid_id),
    UNIQUE(uuid_id)
);

-- ========================================
-- SIMPLIFIED EVALUATION SCHEMA
-- ========================================

-- User evaluations - metadata about user's evaluation session
CREATE TABLE user_evaluations (
    id SERIAL PRIMARY KEY,
    user_id INTEGER, -- Legacy column kept for backward compatibility
    user_uuid UUID REFERENCES users(uuid_id) ON DELETE CASCADE,
    last_updated TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    UNIQUE(user_uuid)
);

-- Skill evaluations - direct relationship between user and skill
CREATE TABLE skill_evaluations (
    id SERIAL PRIMARY KEY,
    user_evaluation_id INTEGER REFERENCES user_evaluations(id) ON DELETE CASCADE,
    skill_id VARCHAR(100) REFERENCES skills(id) ON DELETE CASCADE,
    level skill_level_enum NOT NULL,
    can_mentor BOOLEAN DEFAULT FALSE,
    wants_to_learn BOOLEAN DEFAULT FALSE,
    is_selected BOOLEAN DEFAULT TRUE, -- Replaces selected_skills table
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    UNIQUE(user_evaluation_id, skill_id)
);

-- Indexes for performance
CREATE INDEX idx_teams_direction ON teams(direction);
CREATE INDEX idx_skills_category_id ON skills(category_id);
CREATE INDEX idx_skills_importance ON skills(importance);
CREATE INDEX idx_skill_links_skill_id ON skill_links(skill_id);
CREATE INDEX idx_users_team_id ON users(team_id);
CREATE INDEX idx_users_email ON users(email);

CREATE INDEX idx_users_uuid_id ON users(uuid_id); -- Index on UUID for performance
CREATE INDEX idx_user_evaluations_user_uuid ON user_evaluations(user_uuid);
CREATE INDEX idx_user_evaluations_user_id ON user_evaluations(user_id); -- Legacy index
CREATE INDEX idx_skill_evaluations_user_evaluation_id ON skill_evaluations(user_evaluation_id);
CREATE INDEX idx_skill_evaluations_skill_id ON skill_evaluations(skill_id);
CREATE INDEX idx_skill_evaluations_is_selected ON skill_evaluations(is_selected);

-- Update trigger for users table
CREATE OR REPLACE FUNCTION update_updated_at_column()
RETURNS TRIGGER AS $$
BEGIN
    NEW.updated_at = CURRENT_TIMESTAMP;
    RETURN NEW;
END;
$$ language 'plpgsql';

CREATE TRIGGER update_teams_updated_at BEFORE UPDATE ON teams
    FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

CREATE TRIGGER update_skill_categories_updated_at BEFORE UPDATE ON skill_categories
    FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

CREATE TRIGGER update_skills_updated_at BEFORE UPDATE ON skills
    FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

CREATE TRIGGER update_users_updated_at BEFORE UPDATE ON users
    FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

CREATE TRIGGER update_skill_evaluations_updated_at BEFORE UPDATE ON skill_evaluations
    FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

-- Views for easy querying
CREATE VIEW user_skills_summary AS
SELECT 
    u.first_name,
    u.last_name,
    t.name as team_name,
    t.direction,
    sc.name as category_name,
    s.name as skill_name,
    se.level,
    se.can_mentor,
    se.wants_to_learn,
    se.is_selected,
    se.updated_at
FROM users u
JOIN teams t ON u.team_id = t.id
JOIN user_evaluations ue ON u.uuid_id = ue.user_uuid
JOIN skill_evaluations se ON ue.id = se.user_evaluation_id
JOIN skills s ON se.skill_id = s.id
JOIN skill_categories sc ON s.category_id = sc.id;

CREATE VIEW category_skills_count AS
SELECT 
    sc.id as category_id,
    sc.name as category_name,
    COUNT(s.id) as total_skills
FROM skill_categories sc
LEFT JOIN skills s ON sc.id = s.category_id
GROUP BY sc.id, sc.name;