// Toolchain attach / provisioner logic.
//
// In the Sovereign Coven the user maintains their own GCC/LLVM toolchains.
// Instead of downloading pre-built binaries, the engine bind-mounts the
// toolchain directory into the sandbox at /usr/cross and prepends it to
// PATH so the spell's BUILD script invokes the right compiler.
package sandbox

import "fmt"

// Toolchain represents one user-maintained compiler set.
type Toolchain struct {
	Arch    string // x86_64, aarch64
	Path    string // /opt/sorcery-go/toolchains/aarch64-linux-musl
	Sysroot string // target rootfs headers/libs
}

// AttachToolchain bind-mounts the toolchain into the sandbox read-only and
// updates the environment so the compiler is picked up transparently.
func (b *Box) AttachToolchain(tc Toolchain) error {
	if tc.Path == "" {
		return fmt.Errorf("sandbox: toolchain path empty")
	}
	b.Binds = append(b.Binds, tc.Path+":/usr/cross:ro")
	if old, ok := b.Env["PATH"]; ok {
		b.Env["PATH"] = "/usr/cross/bin:" + old
	} else {
		b.Env["PATH"] = "/usr/cross/bin"
	}
	b.Env["CROSS_COMPILE"] = tc.Arch + "-linux-musl-"
	if tc.Sysroot != "" {
		b.Env["SYSROOT"] = tc.Sysroot
	}
	return nil
}