import type { Disposable, Event, FileDecorationProvider, Uri } from 'vscode'
import type { FileChange } from '../explorer/changedTree'
import { EventEmitter, FileDecoration, ThemeColor } from 'vscode'
import { CHANGE_STYLES } from './changedFiles'

/**
 * 审查工单时给 PR 改过的文件上色、挂 M / A / D 徽标，颜色和 VS Code 源代码管理一样；不审查时什么都不挂。
 * 挂在文件 Uri 上：侧栏的行、编辑器标签页上打开的这些文件都带着。
 */
export class ChangeDecorations implements FileDecorationProvider, Disposable {
  private readonly changed = new EventEmitter<Uri[]>()
  readonly onDidChangeFileDecorations: Event<Uri[]> = this.changed.event
  private changes = new Map<string, FileChange>()
  private uris: Uri[] = []

  /** 换成这些文件的改动（空数组清掉），原来挂着的和新挂的都重画。 */
  show(files: readonly { uri: Uri, change: FileChange }[]): void {
    const before = this.uris
    this.changes = new Map(files.map(file => [file.uri.toString(), file.change]))
    this.uris = files.map(file => file.uri)
    this.changed.fire([...before, ...this.uris])
  }

  provideFileDecoration(uri: Uri): FileDecoration | undefined {
    const change = this.changes.get(uri.toString())
    if (!change)
      return undefined
    const style = CHANGE_STYLES[change]
    return new FileDecoration(change, style.tooltip, new ThemeColor(style.color))
  }

  dispose(): void {
    this.changed.dispose()
  }
}