package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"os/exec"
	"path"
	"syscall"
	"time"

	"github.com/google/uuid"
	"gogs.inhome.blapointe.com/bel/pttodo/pttodo"
	"gopkg.in/yaml.v2"
)

func edit(config *config) error {
	if !config.edit {
		return nil
	}
	return _edit(config.targets)
}

func _edit(filepaths []string) error {
	tempDir, err := ioutil.TempDir(os.TempDir(), "edit-pttodo-*")
	if err != nil {
		return err
	}
	originals := map[string]pttodo.Root{}
	lastModified := map[string]time.Time{}
	for _, target := range filepaths {
		var original pttodo.Root
		if r, err := filePathReader(target); err != nil {
			return err
		} else if err := yaml.NewDecoder(r).Decode(&original); err != nil {
			return err
		} else if c, err := yaml.Marshal(original.Todo); err != nil {
			return err
		} else if err := ioutil.WriteFile(path.Join(tempDir, path.Base(target)), c, os.ModePerm); err != nil {
			return err
		}
		originals[target] = original
		if info, _ := os.Stat(target); info != nil {
			lastModified[target] = info.ModTime()
		} else {
			lastModified[target] = time.Time{}
		}
	}
	if err := vimd(tempDir); err != nil {
		return err
	}
	for _, target := range filepaths {
		for {
			err := func() error {
				var todos []pttodo.Todo
				if r, err := filePathReader(path.Join(tempDir, path.Base(target))); err != nil {
					return err
				} else if err := yaml.NewDecoder(r).Decode(&todos); err != nil {
					return err
				}
				return nil
			}()
			if err == nil {
				break
			}
			log.Printf("%s, press <Enter> to resume editing", err)
			b := make([]byte, 1)
			if _, err := os.Stdin.Read(b); err != nil {
				return err
			}
			if err := vimd(tempDir); err != nil {
				return err
			}
		}
	}
	for _, target := range filepaths {
		r, err := filePathReader(path.Join(tempDir, path.Base(target)))
		if err != nil {
			return err
		}
		var newTodos []pttodo.Todo
		if err := yaml.NewDecoder(r).Decode(&newTodos); err != nil {
			return err
		}
		original := originals[target]

		newTodoIDs := map[string]struct{}{}
		for i := range newTodos {
			newTodoIDs[newTodos[i].ID()] = struct{}{}
		}

		for i := range original.Todo {
			if _, ok := newTodoIDs[original.Todo[i].ID()]; !ok {
				original.Todo[i].TS = pttodo.TS(time.Now().Unix())
				if string(original.Todo[i].Schedule) != "" && !original.Todo[i].Triggered() {
					original.Scheduled = append(original.Scheduled, original.Todo[i])
				}
				original.Done = append(original.Done, original.Todo[i])
			}
		}
		original.Todo = newTodos

		original.AutoMove()

		c, err := yaml.Marshal(original)
		if err != nil {
			return err
		}
		outputPath := target
		if info, _ := os.Stat(target); info != nil && info.ModTime() != lastModified[target] {
			outputPath = fmt.Sprintf("%s.%s.%s", outputPath, uuid.New().String(), path.Ext(outputPath))
		}
		if err := ioutil.WriteFile(outputPath, c, os.ModePerm); err != nil {
			return err
		}
	}
	return nil
}

func vimd(d string) error {
	bin := "vim"
	editorbin, err := exec.LookPath(bin)
	if err != nil {
		editorbin, err = exec.LookPath("vi")
	}
	if err != nil {
		return err
	}
	args := []string{editorbin, "-p"}
	files, err := listDir(d)
	if err != nil {
		return err
	}
	args = append(args, files...)
	cpid, err := syscall.ForkExec(
		editorbin,
		args,
		&syscall.ProcAttr{
			Dir:   d,
			Env:   os.Environ(),
			Files: []uintptr{os.Stdin.Fd(), os.Stdout.Fd(), os.Stderr.Fd()},
			Sys:   nil,
		},
	)
	if err != nil {
		return err
	}
	proc, err := os.FindProcess(cpid)
	if err != nil {
		return err
	}
	state, err := proc.Wait()
	if err != nil {
		return err
	}
	if exitCode := state.ExitCode(); exitCode != 0 {
		return fmt.Errorf("bad exit code on vim: %d, state: %+v", exitCode, state)
	}
	return nil
}