package database

// TimetableSolutionMigrations creates tt_solution + tt_lesson for the solver
// pipeline. One run of the solver produces exactly one tt_solution row plus
// many tt_lesson rows (one per scheduled class-subject hour).
//
// Status flow:
//
//	pending → running → completed | failed | infeasible
//
// hard_score / soft_score come straight from Timefold's HardSoftScore. Lower
// (more negative) hard_score means more hard-constraint violations; the UI
// only ever offers solutions with hard_score == 0 as "valid".
func TimetableSolutionMigrations() []string {
	return []string{
		`CREATE TABLE IF NOT EXISTS tt_solution (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			created_by_user_id UUID NOT NULL,
			name VARCHAR(120),
			status VARCHAR(20) NOT NULL DEFAULT 'pending',
			hard_score INT,
			soft_score INT,
			error_message TEXT,
			started_at TIMESTAMPTZ,
			finished_at TIMESTAMPTZ,
			created_at TIMESTAMPTZ DEFAULT NOW()
		)`,

		`CREATE TABLE IF NOT EXISTS tt_lesson (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			solution_id UUID NOT NULL REFERENCES tt_solution(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,
			teacher_id UUID NOT NULL REFERENCES tt_teacher(id) ON DELETE CASCADE,
			room_id UUID REFERENCES tt_room(id) ON DELETE SET NULL,
			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),
			pinned BOOLEAN NOT NULL DEFAULT false,
			created_at TIMESTAMPTZ DEFAULT NOW(),
			UNIQUE(solution_id, class_id, day_of_week, period_index),
			UNIQUE(solution_id, teacher_id, day_of_week, period_index),
			UNIQUE(solution_id, room_id, day_of_week, period_index)
		)`,

		`CREATE INDEX IF NOT EXISTS idx_tt_solution_user ON tt_solution(created_by_user_id)`,
		`CREATE INDEX IF NOT EXISTS idx_tt_lesson_solution ON tt_lesson(solution_id)`,
		`CREATE INDEX IF NOT EXISTS idx_tt_lesson_class ON tt_lesson(class_id)`,
		`CREATE INDEX IF NOT EXISTS idx_tt_lesson_teacher ON tt_lesson(teacher_id)`,

		// Phase 7: plan versioning + per-solve solver-timeout override.
		`ALTER TABLE tt_solution ADD COLUMN IF NOT EXISTS parent_solution_id UUID REFERENCES tt_solution(id) ON DELETE SET NULL`,
		`ALTER TABLE tt_solution ADD COLUMN IF NOT EXISTS seconds_limit INT`,
	}
}