-- Migration 001: Initial Schema
-- Creates the core tables for the weight tracker app

-- Users table
CREATE TABLE IF NOT EXISTS users (
    id SERIAL PRIMARY KEY,
    username VARCHAR(50) UNIQUE NOT NULL,
    password_hash VARCHAR(255) NOT NULL,
    display_name VARCHAR(100),
    height_cm DECIMAL(5,1),
    age INTEGER,
    gender VARCHAR(20),
    goal_weight_kg DECIMAL(5,1),
    starting_weight_kg DECIMAL(5,1),
    created_at TIMESTAMP DEFAULT NOW()
);

-- Check-ins table
CREATE TABLE IF NOT EXISTS checkins (
    id SERIAL PRIMARY KEY,
    user_id INTEGER REFERENCES users(id) ON DELETE CASCADE,
    weight_kg DECIMAL(5,1) NOT NULL,
    bmi DECIMAL(4,1),
    notes TEXT,
    checked_in_at TIMESTAMP DEFAULT NOW()
);

-- Milestones table
CREATE TABLE IF NOT EXISTS milestones (
    id SERIAL PRIMARY KEY,
    user_id INTEGER REFERENCES users(id) ON DELETE CASCADE,
    milestone_key VARCHAR(50) NOT NULL,
    achieved_at TIMESTAMP DEFAULT NOW(),
    UNIQUE(user_id, milestone_key)
);

-- Challenges table
CREATE TABLE IF NOT EXISTS challenges (
    id SERIAL PRIMARY KEY,
    title VARCHAR(200) NOT NULL,
    description TEXT,
    target_type VARCHAR(30) NOT NULL,
    target_value DECIMAL(8,2) NOT NULL,
    start_date DATE NOT NULL,
    end_date DATE NOT NULL,
    created_at TIMESTAMP DEFAULT NOW()
);

-- Challenge participants
CREATE TABLE IF NOT EXISTS challenge_participants (
    id SERIAL PRIMARY KEY,
    challenge_id INTEGER REFERENCES challenges(id) ON DELETE CASCADE,
    user_id INTEGER REFERENCES users(id) ON DELETE CASCADE,
    completed BOOLEAN DEFAULT FALSE,
    completed_at TIMESTAMP,
    UNIQUE(challenge_id, user_id)
);

-- Indexes
CREATE INDEX IF NOT EXISTS idx_checkins_user_date ON checkins(user_id, checked_in_at DESC);
CREATE INDEX IF NOT EXISTS idx_milestones_user ON milestones(user_id);

-- Migrations tracking table
CREATE TABLE IF NOT EXISTS schema_migrations (
    version INTEGER PRIMARY KEY,
    applied_at TIMESTAMP DEFAULT NOW()
);