package editor

import (
	"errors"
	"fmt"
	"log/slog"
	"os"
	"path/filepath"

	"code.chimeric.al/dwrz/wen/internal/editor/buffer"
	"code.chimeric.al/dwrz/wen/internal/editor/event"
)

// load files into editor buffers.
func (e *Editor) load(files []string) {
	// Attempt to deduplicate any files.
	var (
		unique = map[string]struct{}{}
		paths  []string
	)
	for _, f := range files {
		path, err := filepath.Abs(f)
		if err != nil {
			e.log.Error(
				"failed to get absolute path",
				slog.String("file", f),
				slog.Any("error", err),
			)

			path = filepath.Clean(f)
		}

		if _, exists := unique[path]; !exists {
			unique[path] = struct{}{}
			paths = append(paths, path)
		}
	}

	// Load the files.
	// Set the first successfully loaded file as the active buffer.
	var setActive bool
	for _, name := range paths {
		p := buffer.NewBufferParams{
			Name: name,
			Log:  e.log,
		}

		b, err := buffer.Open(p)
		// Create the file if it doesn't exist.
		if errors.Is(err, os.ErrNotExist) {
			b, err = buffer.Create(p)
		}
		// If there was an error, report it to the user.
		if err != nil {
			e.prompt.SetText(fmt.Sprintf(
				"failed to load buffer %s: %v",
				name, err,
			))
			continue
		}

		e.log.Debug("loaded buffer", slog.String("name", name))

		e.setBuffer(b)

		if !setActive {
			e.setActiveBuffer(name)
			setActive = true
		}
	}

	if e.prompt.Text() == "" {
		e.prompt.SetText("loaded buffers")
	}
}

func (e *Editor) renameBuffer(b *buffer.Buffer, name string) error {
	e.mu.Lock()
	defer e.mu.Unlock()

	oldName := b.Name()
	if err := b.SaveAs(name); err != nil {
		return fmt.Errorf("failed to save as %s: %v", name, err)
	}

	delete(e.buffers, oldName)
	e.buffers[name] = b

	return nil
}

// setActiveBuffer sets the named buffer as the active buffer.
func (e *Editor) setActiveBuffer(name string) {
	e.mu.Lock()
	b, exists := e.buffers[name]
	if !exists {
		e.mu.Unlock()
		e.events <- event.NewError(fmt.Errorf(
			"failed to set active buffer: %s does not exist", name,
		))
		return
	}

	e.active = b
	e.mu.Unlock()

	e.log.Debug("set active buffer", slog.String("name", b.Name()))
}

// setBuffer stores a buffer in the editor's buffer map.
func (e *Editor) setBuffer(b *buffer.Buffer) {
	e.mu.Lock()
	defer e.mu.Unlock()

	e.buffers[b.Name()] = b
}