package optimizer

import "strings"

// passSelfAssignment removes lda X; sta X pairs where the store immediately
// follows the load and neither line is a branch target.
func passSelfAssignment(lines []asmLine) []asmLine {
	var result []asmLine
	skipNext := false

	for i := 0; i < len(lines); i++ {
		if skipNext {
			skipNext = false
			continue
		}

		line := lines[i]

		// Check for lda X; sta X
		if line.isCode && line.opcode == "lda" && !isImmediate(line.operand) && i+1 < len(lines) {
			next := lines[i+1]
			if next.isCode && next.opcode == "sta" && next.operand == line.operand {
				if !strings.Contains(line.operand, "+") {
					skipNext = true // skip sta on next iteration
					continue        // skip lda
				}
			}
		}

		result = append(result, line)
	}

	return result
}