package editor

import (
	"context"
	"errors"
	"fmt"
	"log/slog"
	"runtime/debug"

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

func (e *Editor) Run(ctx context.Context, files []string) error {
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()

	if err := e.terminal.SetRaw(); err != nil {
		return fmt.Errorf("failed to set raw mode: %w", err)
	}
	e.canvas.Reset()

	// Log build info.
	var commit, time string
	bi, ok := debug.ReadBuildInfo()
	if ok {
		for _, s := range bi.Settings {
			switch s.Key {
			case "vcs.revision":
				commit = s.Value
			case "vcs.time":
				time = s.Value
			}
		}
	}
	e.log.Debug(
		"文 version",
		slog.String("commit", commit),
		slog.String("time", time),
	)

	// Reset the terminal before exiting.
	defer func() {
		e.canvas.Reset()

		if err := e.terminal.Reset(); err != nil {
			e.log.Error(
				"failed to reset terminal attributes",
				slog.Any("error", err),
			)
		}
	}()

	// Start reading user input.
	// The reader may be blocked in a read when the editor ends.
	// The reader stops when the process stops.
	go func() {
		if err := e.reader.Run(ctx); err != nil && !errors.Is(err, context.Canceled) {
			e.events <- event.NewError(err)
		}
	}()

	// Open the files and render the initial state.
	e.load(files)
	if err := e.canvas.Render(e.active, e.prompt); err != nil {
		return fmt.Errorf("failed to render: %w", err)
	}

	// Main loop.
	for {
		select {
		case <-ctx.Done():
			e.log.DebugContext(ctx, "context done: stopping")
			return nil

		case ev := <-e.events:
			switch t := ev.(type) {
			case *event.Error:
				return t

			case *event.Message:
				e.prompt.SetText(t.Text())

				if err := e.canvas.Render(
					e.active, e.prompt,
				); err != nil {
					return fmt.Errorf(
						"failed to render: %w", err,
					)
				}

			case *event.Quit:
				return nil
			}

		case event := <-e.input:
			if e.prompt.IsPrompt() {
				if err := e.promptInput(event); err != nil {
					return fmt.Errorf(
						"failed to process input: %w",
						err,
					)
				}
			} else {
				if err := e.bufferInput(event); err != nil {
					return fmt.Errorf(
						"failed to process input: %w",
						err,
					)
				}
			}

			if err := e.canvas.Render(
				e.active, e.prompt,
			); err != nil {
				return fmt.Errorf("failed to render: %w", err)
			}
		}
	}
}