package build

import (
	"sync"

	"git.akyoto.dev/cli/q/src/errors"
)

// compile waits for the scan to finish and compiles all functions.
func compile(functions <-chan *Function, errs <-chan error) (Result, error) {
	result := Result{}
	allFunctions := map[string]*Function{}

	for functions != nil || errs != nil {
		select {
		case err, ok := <-errs:
			if !ok {
				errs = nil
				continue
			}

			return result, err

		case function, ok := <-functions:
			if !ok {
				functions = nil
				continue
			}

			allFunctions[function.Name] = function
		}
	}

	compileFunctions(allFunctions)

	for _, function := range allFunctions {
		if function.err != nil {
			return result, function.err
		}

		result.InstructionCount += len(function.assembler.Instructions)
	}

	main, exists := allFunctions["main"]

	if !exists {
		return result, errors.MissingMainFunction
	}

	result.Main = main
	result.Functions = allFunctions
	return result, nil
}

// compileFunctions starts a goroutine for each function compilation and waits for completion.
func compileFunctions(functions map[string]*Function) {
	wg := sync.WaitGroup{}

	for _, function := range functions {
		wg.Add(1)

		go func() {
			defer wg.Done()
			function.Compile()
		}()
	}

	wg.Wait()
}