package database

// TimetableMigrations returns the SQL statements that create all timetable-related
// tables. They are applied idempotently via CREATE TABLE IF NOT EXISTS.
func TimetableMigrations() []string {
	return []string{
		// Classes (school-wide, distinct from per-teacher `classes` table)
		`CREATE TABLE IF NOT EXISTS tt_class (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			name VARCHAR(50) NOT NULL,
			grade_level INT NOT NULL,
			student_count INT DEFAULT 0,
			notes TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(created_by_user_id, name)
		)`,

		// Time periods (Mon=1..Sun=7, period_index = 1..N)
		`CREATE TABLE IF NOT EXISTS tt_period (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			day_of_week INT NOT NULL CHECK (day_of_week BETWEEN 1 AND 7),
			period_index INT NOT NULL CHECK (period_index >= 1),
			start_time TIME NOT NULL,
			end_time TIME NOT NULL,
			is_break BOOLEAN DEFAULT false,
			label VARCHAR(50),
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(created_by_user_id, day_of_week, period_index)
		)`,

		// Rooms
		`CREATE TABLE IF NOT EXISTS tt_room (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			name VARCHAR(50) NOT NULL,
			room_type VARCHAR(30),
			capacity INT DEFAULT 30,
			floor_level INT DEFAULT 0,
			has_elevator BOOLEAN DEFAULT true,
			notes TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(created_by_user_id, name)
		)`,

		// Subjects (school-wide, distinct from per-teacher `subjects`)
		`CREATE TABLE IF NOT EXISTS tt_subject (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			name VARCHAR(100) NOT NULL,
			short_code VARCHAR(10) NOT NULL,
			color VARCHAR(7),
			is_main_subject BOOLEAN DEFAULT false,
			required_room_type VARCHAR(30),
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(created_by_user_id, short_code)
		)`,

		// Teachers (planning resource, NOT a BreakPilot user)
		`CREATE TABLE IF NOT EXISTS tt_teacher (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			first_name VARCHAR(100) NOT NULL,
			last_name VARCHAR(100) NOT NULL,
			short_code VARCHAR(10) NOT NULL,
			employment_percentage INT DEFAULT 100,
			max_hours_week INT DEFAULT 28,
			notes TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(created_by_user_id, short_code)
		)`,

		// Curriculum: weekly hour count per class+subject
		`CREATE TABLE IF NOT EXISTS tt_curriculum (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			class_id UUID NOT NULL REFERENCES tt_class(id) ON DELETE CASCADE,
			subject_id UUID NOT NULL REFERENCES tt_subject(id) ON DELETE CASCADE,
			weekly_hours INT NOT NULL CHECK (weekly_hours >= 1),
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(class_id, subject_id)
		)`,

		// Assignment: which teacher teaches which subject in which class
		`CREATE TABLE IF NOT EXISTS tt_assignment (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			teacher_id UUID NOT NULL REFERENCES tt_teacher(id) ON DELETE CASCADE,
			class_id UUID NOT NULL REFERENCES tt_class(id) ON DELETE CASCADE,
			subject_id UUID NOT NULL REFERENCES tt_subject(id) ON DELETE CASCADE,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(teacher_id, class_id, subject_id)
		)`,

		// Indexes
		`CREATE INDEX IF NOT EXISTS idx_tt_class_user ON tt_class(created_by_user_id)`,
		`CREATE INDEX IF NOT EXISTS idx_tt_period_user ON tt_period(created_by_user_id)`,
		`CREATE INDEX IF NOT EXISTS idx_tt_room_user ON tt_room(created_by_user_id)`,
		`CREATE INDEX IF NOT EXISTS idx_tt_subject_user ON tt_subject(created_by_user_id)`,
		`CREATE INDEX IF NOT EXISTS idx_tt_teacher_user ON tt_teacher(created_by_user_id)`,
		`CREATE INDEX IF NOT EXISTS idx_tt_curriculum_class ON tt_curriculum(class_id)`,
		`CREATE INDEX IF NOT EXISTS idx_tt_assignment_teacher ON tt_assignment(teacher_id)`,
		`CREATE INDEX IF NOT EXISTS idx_tt_assignment_class ON tt_assignment(class_id)`,
	}
}