import type { Argv, ArgumentsCamelCase } from "yargs"
import { CLICommand } from "../cli/CLICommand"
import { parseTodoFile, writeTodoFile } from "../file"
import { getCurrentBranch, branchExists, commitFileWithBody } from "../git"
import { validateStatusTransition } from "../issue"

export class StartCommand extends CLICommand {
  readonly name = "start <id>"
  readonly help = "Start work on an issue"
  readonly description = "Set issue to in-progress (must be on develop)"

  addArguments(yargs: Argv): Argv {
    return yargs
      .positional("id", { type: "number", demandOption: true })
      .option("plan", {
        type: "string",
        demandOption: true,
        description: "High-level description of planned approach",
      })
  }

  async execute(args: ArgumentsCamelCase): Promise<number> {
    const branch = getCurrentBranch()
    if (branch !== "develop") {
      console.error(`Must be on develop to start an issue (currently on ${branch})`)
      return 1
    }

    const todo = await parseTodoFile()
    const issue = todo.issues.find(i => i.id === args.id)
    if (!issue) {
      console.error(`Issue #${args.id} not found`)
      return 1
    }

    const err = validateStatusTransition(issue.status, "in-progress")
    if (err) {
      console.error(err)
      return 1
    }

    // Check that the issue branch doesn't already exist
    const issueBranch = `${issue.type}/${issue.id}`
    if (branchExists(issueBranch)) {
      console.error(`Branch ${issueBranch} already exists`)
      return 1
    }

    issue.status = "in-progress"
    writeTodoFile(todo)
    commitFileWithBody(
      "TODO",
      `todo(${issue.id}): in-progress`,
      args.plan as string
    )
    console.log(`Issue #${issue.id} is now in-progress`)
    console.log(`Create the issue branch: git checkout -b ${issueBranch}`)
    return 0
  }
}