module main

import strings
import os

struct Generator {
mut:
	out strings.Builder
}

fn mangle_var(name string) string {
	return 'v${name}'
}

fn (mut g Generator) get_c_type(typ string) string {
	c_type := if typ == 'real' { 'double' } else { typ }
	return c_type
}

fn (mut g Generator) gen_stmt(stmt Stmt) {
	match stmt {
		VarDecl {
			c_type := g.get_c_type(stmt.type)
			if stmt.const {
				g.out.write_string('const ')
			}
			g.out.write_string('${c_type} ${mangle_var(stmt.name)} = ')
			g.gen_expr(stmt.value)
			g.out.writeln(';')
		}
		ExprStmt {
			g.gen_expr(stmt.expr)
			g.out.writeln(';')
		}
		ReturnStmt {
			g.out.write_string('return ')
			g.gen_expr(stmt.expr)
			g.out.writeln(';')
		}
		Block {
			g.out.writeln('{')
			for inner_stmt in stmt.stmts {
				g.gen_stmt(inner_stmt)
			}
			g.out.writeln('}')
		}
		FuncDecl {
			c_type := g.get_c_type(stmt.ret_type)
			g.out.write_string('${c_type} ${stmt.name}(')
			for param in stmt.params {
				g.gen_stmt(param)
				if param != stmt.params[stmt.params.len-1]{
					g.out.write_string(', ')
				}
			}
			g.out.write_string(')')
			g.gen_stmt(stmt.block)
		}
		Param {
			c_type := g.get_c_type(stmt.type)
			g.out.write_string('${c_type} ${mangle_var(stmt.name)}')
		}
	}
}

fn (mut g Generator) gen_expr(expr Expr) {
	match expr {
		RealLiteral {
			g.out.write_string(expr.val.str())
		}
		IntegerLiteral {
			g.out.write_string(expr.val.str())
		}
		BoolLiteral {
			g.out.write_string(expr.val.str())
		}
		Variable {
			g.out.write_string(mangle_var(expr.name))
		}
		UnaryExpr {
			g.out.write_string('${expr.ident}${expr.op}')
		}
		BinaryExpr {
			g.out.write_string('(')
			g.gen_expr(expr.left)
			g.out.write_string(' ${expr.op} ')
			g.gen_expr(expr.right)
			g.out.write_string(')')
		}
		PrintExpr {
			g.out.write_string('printf(\"%')
			format := match expr.type {
				'int', 'bool'  {'d'}
				'real' {'lf'}
				else   {panic("Tried printing illegal type")}
			}
			g.out.write_string('${format}\\n\", ')
			g.gen_expr(expr.expr)
			g.out.write_string(')')
		}
		TypeCast {
			c_type := g.get_c_type(expr.type)
			g.out.write_string('(${c_type})')
			g.gen_expr(expr.expr)
		}
		ParenExpr {
			g.out.write_string('(')
			g.gen_expr(expr.expr)
			g.out.write_string(')')
		}
		FnCall {
			g.out.write_string('${expr.name}(')
			for arg in expr.args {
				g.gen_expr(arg)
				if arg != expr.args[expr.args.len-1]{
					g.out.write_string(', ')
				}
			}
			g.out.write_string(')')
		}
		else {panic("Unimplemented expression")}
	}
}

fn (mut g Generator) gen_c(program []Stmt) string {
	g.out.writeln('#include <stdio.h>')
	g.out.writeln('#include <stdbool.h>')
	for stmt in program {
		g.gen_stmt(stmt)
	}

	return g.out.str()

}

fn compile_with_clang(c_code string, output_name string, keep_c bool) {
    // 1. Write the C code to a temporary file
    c_file := 'middle_c.c'
    os.write_file(c_file, c_code) or {
        eprintln('Failed to write C file: $err')
        return
    }

    // 2. Construct the clang command
    // We'll use -O2 for optimization and -o to specify the output binary
    clang_cmd := 'clang ${c_file} -o ${output_name} -O2'

    println('Executing: ${clang_cmd}')

    // 3. Run the command
    result := os.execute(clang_cmd)

    if result.exit_code != 0 {
        eprintln('Clang Compilation Failed:')
        eprintln(result.output)
    } else {
        println('Compilation successful! Binary created: $output_name')
        // Optional: Remove the temporary C file
				if !keep_c {
        	os.rm(c_file) or { }
				}
    }
}