package framework

import (
	"flag"
	"fmt"
	"os"
	"path/filepath"

	"github.com/bazelbuild/rules_go/go/runfiles"
	"github.com/peterbourgon/ff/v3"

	"edge-infra.dev/pkg/lib/build/bazel"
	"edge-infra.dev/test/framework/config"
)

var (
	cfgFlagName = "test-config"
	cfgPath     = "test/config.json"
	cfgFlag     string
)

// HandleFlags is the key entrypoint for test configuration for the framework.
// It sets up flags for providing test configuration files, reading flags from
// environment variables (flag separators are turned into `_` by ff), registering
// common framework flags, and copying all of the flags registered via
// `config.AddOptions` to the flag set.
// NOTE: Currently must be called from TestMain so that flags are handled by
//
//	the time the first test begins.
func HandleFlags() {
	// register flag for config file path, so ff can find the it
	config.Flags.StringVar(&cfgFlag, cfgFlagName, resolveCfgPath(), "path to test configuration file")
	// copy all the flags from the global flagset each test suite registers
	// config options with to the command line for parsing
	config.CopyFlags(config.Flags, flag.CommandLine)
	// register base framework flags
	RegisterCommonFlags(flag.CommandLine)
	// parse test configuration
	if err := ff.Parse(flag.CommandLine, os.Args[1:],
		ff.WithConfigFileFlag(cfgFlagName),
		ff.WithConfigFileParser(ff.JSONParser),
		ff.WithAllowMissingConfigFile(true),
		ff.WithIgnoreUndefined(true),
	); err != nil {
		panic(err)
	}
	// validate parsed common flags
	Context.Validate()
}

// resolve config attempts to locate the test configuration file. if a bazel
// runtime is detected, it will look for config.json in the runfiles. otherwise,
// it tries to find the repo root and build a relative path from root.
func resolveCfgPath() string {
	if bazel.IsBazelRun() || bazel.IsBazelTest() {
		rfilesPath := filepath.Join("edge_infa", cfgPath)
		path, err := runfiles.Rlocation(rfilesPath)
		if err != nil {
			panic(fmt.Sprintf(
				"failed to locate test config file %s in Bazel sandbox: %v",
				rfilesPath, err,
			))
		}
		return path
	}
	cwd, err := os.Getwd()
	if err != nil {
		panic(fmt.Sprintf("failed to determine cwd: %v", err))
	}
	return filepath.Join(bazel.FindRepoRootOrDie(cwd), cfgPath)
}