package cgi

import (
	"bytes"
	"context"
	"fmt"
	"path/filepath"
	"strings"

	sr "tildegit.org/tjp/sliderule"
	"tildegit.org/tjp/sliderule/gemini"
	"tildegit.org/tjp/sliderule/logging"
)

// GeminiCGIDirectory runs any executable files relative to a root directory on the file system.
//
// It will also find and run any executables _part way_ through the path, so for example
// a request for /foo/bar/baz can also run an executable found at /foo or  /foo/bar. In
// such a case the PATH_INFO environment variable will include the remaining portion of
// the URI path.
func GeminiCGIDirectory(fsroot, urlroot, cmd string) sr.Handler {
	fsroot = strings.TrimRight(fsroot, "/")
	return sr.HandlerFunc(func(ctx context.Context, request *sr.Request) *sr.Response {
		if !strings.HasPrefix(request.Path, urlroot) {
			return nil
		}

		execpath, pathinfo, err := ResolveCGI(request.Path[len(urlroot):], fsroot)
		if err != nil {
			return gemini.Failure(err)
		}
		if execpath == "" {
			return nil
		}
		workdir := filepath.Dir(execpath)

		if cmd != "" {
			execpath = cmd
		}

		stderr := &bytes.Buffer{}
		stdout, exitCode, err := RunCGI(ctx, request, execpath, pathinfo, workdir, stderr)
		if err != nil {
			return gemini.Failure(err)
		}
		if exitCode != 0 {
			ctx.Value("warnlog").(logging.Logger).Log(
				"msg", "cgi exited with non-zero exit code",
				"code", exitCode,
				"stderr", stderr.String(),
			)
			return gemini.CGIError(fmt.Sprintf("CGI process exited with status %d", exitCode))
		}

		response, err := gemini.ParseResponse(stdout)
		if err != nil {
			return gemini.Failure(err)
		}
		return response
	})
}