-- MerchantsOfHope-SupplyANdDemandPortal Database Schema

-- Users table (for authentication and user management)
CREATE TABLE IF NOT EXISTS users (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    email VARCHAR(255) UNIQUE NOT NULL,
    password_hash VARCHAR(255) NOT NULL,
    first_name VARCHAR(100) NOT NULL,
    last_name VARCHAR(100) NOT NULL,
    role VARCHAR(50) NOT NULL CHECK (role IN ('admin', 'recruiter', 'employer', 'candidate')),
    is_active BOOLEAN DEFAULT true,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Employers table
CREATE TABLE IF NOT EXISTS employers (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id UUID REFERENCES users(id) ON DELETE CASCADE,
    company_name VARCHAR(255) NOT NULL,
    industry VARCHAR(100),
    company_size VARCHAR(50),
    website VARCHAR(255),
    description TEXT,
    address TEXT,
    phone VARCHAR(20),
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Candidates table
CREATE TABLE IF NOT EXISTS candidates (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id UUID REFERENCES users(id) ON DELETE CASCADE,
    phone VARCHAR(20),
    location VARCHAR(255),
    linkedin_url VARCHAR(255),
    github_url VARCHAR(255),
    portfolio_url VARCHAR(255),
    bio TEXT,
    skills TEXT[],
    experience_level VARCHAR(50),
    availability VARCHAR(50),
    salary_expectation INTEGER,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Job postings table
CREATE TABLE IF NOT EXISTS jobs (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    employer_id UUID REFERENCES employers(id) ON DELETE CASCADE,
    title VARCHAR(255) NOT NULL,
    description TEXT NOT NULL,
    requirements TEXT[],
    responsibilities TEXT[],
    location VARCHAR(255),
    employment_type VARCHAR(50) CHECK (employment_type IN ('full-time', 'part-time', 'contract', 'internship')),
    salary_min INTEGER,
    salary_max INTEGER,
    currency VARCHAR(3) DEFAULT 'USD',
    status VARCHAR(50) DEFAULT 'active' CHECK (status IN ('active', 'paused', 'closed', 'draft')),
    remote_allowed BOOLEAN DEFAULT false,
    experience_level VARCHAR(50),
    skills_required TEXT[],
    benefits TEXT[],
    application_deadline DATE,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Applications table
CREATE TABLE IF NOT EXISTS applications (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    job_id UUID REFERENCES jobs(id) ON DELETE CASCADE,
    candidate_id UUID REFERENCES candidates(id) ON DELETE CASCADE,
    status VARCHAR(50) DEFAULT 'applied' CHECK (status IN ('applied', 'reviewed', 'shortlisted', 'interviewed', 'offered', 'rejected', 'withdrawn')),
    cover_letter TEXT,
    notes TEXT,
    applied_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    UNIQUE(job_id, candidate_id)
);

-- Resumes table
CREATE TABLE IF NOT EXISTS resumes (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    candidate_id UUID REFERENCES candidates(id) ON DELETE CASCADE,
    filename VARCHAR(255) NOT NULL,
    original_name VARCHAR(255) NOT NULL,
    file_path VARCHAR(500) NOT NULL,
    file_size INTEGER NOT NULL,
    mime_type VARCHAR(100) NOT NULL,
    is_primary BOOLEAN DEFAULT false,
    uploaded_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Interviews table
CREATE TABLE IF NOT EXISTS interviews (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    application_id UUID REFERENCES applications(id) ON DELETE CASCADE,
    scheduled_at TIMESTAMP NOT NULL,
    duration_minutes INTEGER DEFAULT 60,
    interview_type VARCHAR(50) CHECK (interview_type IN ('phone', 'video', 'in-person', 'technical')),
    location VARCHAR(255),
    meeting_link VARCHAR(500),
    notes TEXT,
    status VARCHAR(50) DEFAULT 'scheduled' CHECK (status IN ('scheduled', 'completed', 'cancelled', 'rescheduled')),
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Create indexes for better performance
CREATE INDEX IF NOT EXISTS idx_users_email ON users(email);
CREATE INDEX IF NOT EXISTS idx_users_role ON users(role);
CREATE INDEX IF NOT EXISTS idx_employers_user_id ON employers(user_id);
CREATE INDEX IF NOT EXISTS idx_candidates_user_id ON candidates(user_id);
CREATE INDEX IF NOT EXISTS idx_jobs_employer_id ON jobs(employer_id);
CREATE INDEX IF NOT EXISTS idx_jobs_status ON jobs(status);
CREATE INDEX IF NOT EXISTS idx_applications_job_id ON applications(job_id);
CREATE INDEX IF NOT EXISTS idx_applications_candidate_id ON applications(candidate_id);
CREATE INDEX IF NOT EXISTS idx_applications_status ON applications(status);
CREATE INDEX IF NOT EXISTS idx_resumes_candidate_id ON resumes(candidate_id);
CREATE INDEX IF NOT EXISTS idx_interviews_application_id ON interviews(application_id);

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

-- Apply updated_at triggers
DROP TRIGGER IF EXISTS update_users_updated_at ON users;
CREATE TRIGGER update_users_updated_at BEFORE UPDATE ON users FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

DROP TRIGGER IF EXISTS update_employers_updated_at ON employers;
CREATE TRIGGER update_employers_updated_at BEFORE UPDATE ON employers FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

DROP TRIGGER IF EXISTS update_candidates_updated_at ON candidates;
CREATE TRIGGER update_candidates_updated_at BEFORE UPDATE ON candidates FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

DROP TRIGGER IF EXISTS update_jobs_updated_at ON jobs;
CREATE TRIGGER update_jobs_updated_at BEFORE UPDATE ON jobs FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

DROP TRIGGER IF EXISTS update_applications_updated_at ON applications;
CREATE TRIGGER update_applications_updated_at BEFORE UPDATE ON applications FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

DROP TRIGGER IF EXISTS update_interviews_updated_at ON interviews;
CREATE TRIGGER update_interviews_updated_at BEFORE UPDATE ON interviews FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();