package database

// TimetableConstraintMigrations returns the DDL for all 15 constraint tables.
// Each table follows the same shape:
//   - id / created_by_user_id / is_hard / weight / active / note / created_at
//   - one or more FKs to tt_teacher / tt_class / tt_subject / tt_room
//
// FK ON DELETE CASCADE removes constraints when their parent (teacher/room/etc.)
// is deleted — the rules become meaningless without the referenced resource.
func TimetableConstraintMigrations() []string {
	return []string{
		// ---------- Teacher constraints (6) ----------

		`CREATE TABLE IF NOT EXISTS tt_constraint_teacher_unavailable_day (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			teacher_id UUID NOT NULL REFERENCES tt_teacher(id) ON DELETE CASCADE,
			day_of_week INT NOT NULL CHECK (day_of_week BETWEEN 1 AND 7),
			is_hard BOOLEAN NOT NULL DEFAULT true,
			weight INT NOT NULL DEFAULT 100 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(teacher_id, day_of_week)
		)`,

		`CREATE TABLE IF NOT EXISTS tt_constraint_teacher_unavailable_window (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			teacher_id UUID NOT NULL REFERENCES tt_teacher(id) ON DELETE CASCADE,
			day_of_week INT NOT NULL CHECK (day_of_week BETWEEN 1 AND 7),
			start_time TIME NOT NULL,
			end_time TIME NOT NULL,
			is_hard BOOLEAN NOT NULL DEFAULT true,
			weight INT NOT NULL DEFAULT 100 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			CHECK (end_time > start_time)
		)`,

		`CREATE TABLE IF NOT EXISTS tt_constraint_teacher_max_hours_day (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			teacher_id UUID NOT NULL REFERENCES tt_teacher(id) ON DELETE CASCADE,
			max_hours INT NOT NULL CHECK (max_hours BETWEEN 1 AND 12),
			is_hard BOOLEAN NOT NULL DEFAULT false,
			weight INT NOT NULL DEFAULT 50 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(teacher_id)
		)`,

		`CREATE TABLE IF NOT EXISTS tt_constraint_teacher_max_hours_week (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			teacher_id UUID NOT NULL REFERENCES tt_teacher(id) ON DELETE CASCADE,
			max_hours INT NOT NULL CHECK (max_hours BETWEEN 1 AND 40),
			is_hard BOOLEAN NOT NULL DEFAULT true,
			weight INT NOT NULL DEFAULT 100 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(teacher_id)
		)`,

		`CREATE TABLE IF NOT EXISTS tt_constraint_teacher_excluded_subject (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			teacher_id UUID NOT NULL REFERENCES tt_teacher(id) ON DELETE CASCADE,
			subject_id UUID NOT NULL REFERENCES tt_subject(id) ON DELETE CASCADE,
			is_hard BOOLEAN NOT NULL DEFAULT true,
			weight INT NOT NULL DEFAULT 100 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(teacher_id, subject_id)
		)`,

		`CREATE TABLE IF NOT EXISTS tt_constraint_teacher_excluded_room (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			teacher_id UUID NOT NULL REFERENCES tt_teacher(id) ON DELETE CASCADE,
			room_id UUID NOT NULL REFERENCES tt_room(id) ON DELETE CASCADE,
			is_hard BOOLEAN NOT NULL DEFAULT true,
			weight INT NOT NULL DEFAULT 100 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(teacher_id, room_id)
		)`,

		// ---------- Subject constraints (5) ----------

		`CREATE TABLE IF NOT EXISTS tt_constraint_subject_min_day_gap (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			subject_id UUID NOT NULL REFERENCES tt_subject(id) ON DELETE CASCADE,
			min_gap_days INT NOT NULL CHECK (min_gap_days BETWEEN 1 AND 4),
			is_hard BOOLEAN NOT NULL DEFAULT false,
			weight INT NOT NULL DEFAULT 70 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(subject_id)
		)`,

		`CREATE TABLE IF NOT EXISTS tt_constraint_subject_max_consecutive (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			subject_id UUID NOT NULL REFERENCES tt_subject(id) ON DELETE CASCADE,
			max_consecutive INT NOT NULL CHECK (max_consecutive BETWEEN 1 AND 5),
			is_hard BOOLEAN NOT NULL DEFAULT true,
			weight INT NOT NULL DEFAULT 100 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(subject_id)
		)`,

		`CREATE TABLE IF NOT EXISTS tt_constraint_subject_contiguous_when_repeated (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			subject_id UUID NOT NULL REFERENCES tt_subject(id) ON DELETE CASCADE,
			is_hard BOOLEAN NOT NULL DEFAULT true,
			weight INT NOT NULL DEFAULT 100 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(subject_id)
		)`,

		`CREATE TABLE IF NOT EXISTS tt_constraint_subject_preferred_period (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			subject_id UUID NOT NULL REFERENCES tt_subject(id) ON DELETE CASCADE,
			period_from INT NOT NULL CHECK (period_from BETWEEN 1 AND 12),
			period_to INT NOT NULL CHECK (period_to BETWEEN 1 AND 12),
			is_hard BOOLEAN NOT NULL DEFAULT false,
			weight INT NOT NULL DEFAULT 40 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			CHECK (period_to >= period_from)
		)`,

		`CREATE TABLE IF NOT EXISTS tt_constraint_subject_double_lesson (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			subject_id UUID NOT NULL REFERENCES tt_subject(id) ON DELETE CASCADE,
			is_hard BOOLEAN NOT NULL DEFAULT false,
			weight INT NOT NULL DEFAULT 60 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(subject_id)
		)`,

		// ---------- Class constraints (2) ----------

		`CREATE TABLE IF NOT EXISTS tt_constraint_class_max_hours_day (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			class_id UUID NOT NULL REFERENCES tt_class(id) ON DELETE CASCADE,
			max_hours INT NOT NULL CHECK (max_hours BETWEEN 1 AND 12),
			is_hard BOOLEAN NOT NULL DEFAULT true,
			weight INT NOT NULL DEFAULT 100 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(class_id)
		)`,

		`CREATE TABLE IF NOT EXISTS tt_constraint_class_no_gaps (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			class_id UUID NOT NULL REFERENCES tt_class(id) ON DELETE CASCADE,
			is_hard BOOLEAN NOT NULL DEFAULT false,
			weight INT NOT NULL DEFAULT 80 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(class_id)
		)`,

		// ---------- Room constraints (2) ----------

		`CREATE TABLE IF NOT EXISTS tt_constraint_room_requires_type (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			subject_id UUID NOT NULL REFERENCES tt_subject(id) ON DELETE CASCADE,
			room_type VARCHAR(30) NOT NULL,
			is_hard BOOLEAN NOT NULL DEFAULT true,
			weight INT NOT NULL DEFAULT 100 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(subject_id, room_type)
		)`,

		`CREATE TABLE IF NOT EXISTS tt_constraint_room_unavailable (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			room_id UUID NOT NULL REFERENCES tt_room(id) ON DELETE CASCADE,
			day_of_week INT NOT NULL CHECK (day_of_week BETWEEN 1 AND 7),
			period_index INT NOT NULL CHECK (period_index BETWEEN 1 AND 12),
			is_hard BOOLEAN NOT NULL DEFAULT true,
			weight INT NOT NULL DEFAULT 100 CHECK (weight BETWEEN 0 AND 100),
			active BOOLEAN NOT NULL DEFAULT true,
			note TEXT,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(room_id, day_of_week, period_index)
		)`,

		// ---------- Indexes ----------

		`CREATE INDEX IF NOT EXISTS idx_tt_c_teacher_unav_day_teacher ON tt_constraint_teacher_unavailable_day(teacher_id)`,
		`CREATE INDEX IF NOT EXISTS idx_tt_c_teacher_unav_win_teacher ON tt_constraint_teacher_unavailable_window(teacher_id)`,
		`CREATE INDEX IF NOT EXISTS idx_tt_c_teacher_excl_subj_teacher ON tt_constraint_teacher_excluded_subject(teacher_id)`,
		`CREATE INDEX IF NOT EXISTS idx_tt_c_teacher_excl_room_teacher ON tt_constraint_teacher_excluded_room(teacher_id)`,
		`CREATE INDEX IF NOT EXISTS idx_tt_c_room_unav_room ON tt_constraint_room_unavailable(room_id)`,
	}
}