// Copyright 2024 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package main

import (
	"context"
	"fmt"

	"golang.org/x/vulndb/internal/gitrepo"
	"golang.org/x/vulndb/internal/report"
)

type setDates struct {
	dates map[string]gitrepo.Dates

	filenameParser
}

func (setDates) name() string { return "set-dates" }

func (setDates) usage() (string, string) {
	const desc = "sets PublishDate of YAML reports"
	return filenameArgs, desc
}

func (sd *setDates) setup(ctx context.Context) error {
	repo, err := gitrepo.Open(ctx, ".")
	if err != nil {
		return err
	}
	dates, err := gitrepo.AllCommitDates(repo, gitrepo.MainReference, report.YAMLDir)
	if err != nil {
		return err
	}
	sd.dates = dates
	return nil
}

func (sd *setDates) close() error { return nil }

// setDates sets the PublishedDate of the report at filename to the oldest
// commit date in the repo that contains that file. (It may someday also set a
// last-modified date, hence the plural.) Since it looks at the commits from
// origin/master, it will only work for reports that are already submitted. Thus
// it isn't useful to run when you're working on a report, only at a later time.
//
// It isn't crucial to run this for every report, because the same logic exists
// in gendb, ensuring that every report has a PublishedDate before being
// transformed into a DB entry. The advantage of using this command is that
// the dates become permanent (if you create and submit a CL after running it).
//
// This intentionally does not set the LastModified of the report: While the
// publication date of a report may be expected not to change, the modification
// date can. Always using the git history as the source of truth for the
// last-modified date avoids confusion if the report YAML and the git history
// disagree.
func (sd *setDates) run(ctx context.Context, filename string) (err error) {
	r, err := report.Read(filename)
	if err != nil {
		return err
	}
	if !r.Published.IsZero() {
		return nil
	}
	d, ok := sd.dates[filename]
	if !ok {
		return fmt.Errorf("can't find git repo commit dates for %q", filename)
	}
	r.Published = d.Oldest
	return r.Write(filename)
}