package prompt

import (
	"strings"
	"testing"

	"git.unkin.net/unkin/teabot/internal/gitea"
)

func TestIssuePromptContainsContextAndConventions(t *testing.T) {
	p := Issue(IssueContext{
		Repo:            "unkin/teabot",
		PersonalityName: "implementer",
		Issue: gitea.Issue{
			Index:   42,
			Title:   "Add a flag",
			Body:    "Please add --verbose",
			Poster:  gitea.User{Login: "alice"},
			HTMLURL: "https://git.unkin.net/unkin/teabot/issues/42",
		},
		Comments: []gitea.Comment{{Poster: gitea.User{Login: "bob"}, Body: "agreed"}},
	})

	mustContain(t, p, "implementer")
	mustContain(t, p, "unkin/teabot")
	mustContain(t, p, "Add a flag")
	mustContain(t, p, "Please add --verbose")
	mustContain(t, p, "Closes #42") // must instruct linking the issue
	mustContain(t, p, "bob: agreed")
	mustContain(t, p, "benvin/") // branch-naming convention
	mustContain(t, p, "present-tense")
}

func TestIssuePromptHandlesEmptyBody(t *testing.T) {
	p := Issue(IssueContext{
		Repo:  "a/b",
		Issue: gitea.Issue{Index: 1, Title: "t"},
	})
	mustContain(t, p, "(no description provided)")
}

func TestPullPromptIncludesDiffAndReviewInstruction(t *testing.T) {
	p := Pull(PullContext{
		Repo:            "unkin/teabot",
		PersonalityName: "reviewer",
		Pull: gitea.PullRequest{
			Index:  7,
			Title:  "Implement thing",
			Body:   "does the thing",
			Poster: gitea.User{Login: "carol"},
			Head:   gitea.Branch{Ref: "benvin/thing"},
			Base:   gitea.Branch{Ref: "main"},
		},
		Diff: "diff --git a/x b/x\n+added line\n",
	})
	mustContain(t, p, "reviewer")
	mustContain(t, p, "PR #7")
	mustContain(t, p, "does the diff actually satisfy")
	mustContain(t, p, "benvin/thing -> main")
	mustContain(t, p, "diff --git a/x b/x")
	mustContain(t, p, "+added line")
}

func TestPullPromptTruncatesHugeDiff(t *testing.T) {
	huge := strings.Repeat("x", 70000)
	p := Pull(PullContext{Repo: "a/b", Pull: gitea.PullRequest{Index: 1}, Diff: huge})
	mustContain(t, p, "[diff truncated]")
	if len(p) > 70000 {
		t.Errorf("prompt not truncated, len=%d", len(p))
	}
}

func TestFollowUpIssueVsPullWording(t *testing.T) {
	issueThread := []gitea.Comment{{Poster: gitea.User{Login: "a"}, Body: "first"}}
	trigger := gitea.Comment{Poster: gitea.User{Login: "human"}, Body: "please tweak it"}

	ip := FollowUp(FollowUpContext{
		Repo: "a/b", Kind: FollowUpIssue, Index: 3, Title: "T",
		URL: "u", Comments: issueThread, NewComment: trigger,
	})
	mustContain(t, ip, "issue #3")
	mustContain(t, ip, "please tweak it")
	mustContain(t, ip, "posted by human")

	pp := FollowUp(FollowUpContext{
		Repo: "a/b", Kind: FollowUpPull, Index: 4, Title: "T2",
		URL: "u", Comments: issueThread, NewComment: trigger,
	})
	mustContain(t, pp, "pull request #4")
	mustContain(t, pp, "check out the PR branch")
}

func mustContain(t *testing.T, haystack, needle string) {
	t.Helper()
	if !strings.Contains(haystack, needle) {
		t.Errorf("prompt missing %q\n---\n%s", needle, haystack)
	}
}