package agent

import "testing"

func base() PRState {
	return PRState{
		Ref:              PRRef{Owner: "unkin", Repo: "repo", Number: 1},
		State:            "open",
		Merged:           false,
		HeadSHA:          "abc123",
		Mergeable:        true,
		CIStatus:         "pending",
		NonAgentComments: 0,
	}
}

func TestMeaningfulChange(t *testing.T) {
	tests := []struct {
		name       string
		mutate     func(s *PRState)
		wantChange bool
	}{
		{
			name:       "no change",
			mutate:     func(s *PRState) {},
			wantChange: false,
		},
		{
			name:       "CI pending to success is benign",
			mutate:     func(s *PRState) { s.CIStatus = "success" },
			wantChange: false,
		},
		{
			name:       "open to merged alerts",
			mutate:     func(s *PRState) { s.Merged = true; s.State = "closed" },
			wantChange: true,
		},
		{
			name:       "open to closed without merge alerts",
			mutate:     func(s *PRState) { s.State = "closed" },
			wantChange: true,
		},
		{
			name:       "new non-agent comment alerts",
			mutate:     func(s *PRState) { s.NonAgentComments = 1 },
			wantChange: true,
		},
		{
			name:       "CI to failure alerts",
			mutate:     func(s *PRState) { s.CIStatus = "failure" },
			wantChange: true,
		},
		{
			name:       "CI to error alerts",
			mutate:     func(s *PRState) { s.CIStatus = "error" },
			wantChange: true,
		},
		{
			name:       "lost mergeability alerts",
			mutate:     func(s *PRState) { s.Mergeable = false },
			wantChange: true,
		},
		{
			name:       "new head sha alone is benign",
			mutate:     func(s *PRState) { s.HeadSHA = "def456" },
			wantChange: false,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			prev := base()
			cur := base()
			tt.mutate(&cur)
			got, reason := MeaningfulChange(prev, cur)
			if got != tt.wantChange {
				t.Errorf("MeaningfulChange() = %v (%q), want %v", got, reason, tt.wantChange)
			}
			if got && reason == "" {
				t.Errorf("change reported without a reason")
			}
		})
	}
}

// A comment that only the agent posts must not alert: the non-agent count is
// unchanged, so MeaningfulChange sees nothing.
func TestMeaningfulChangeAgentCommentIgnored(t *testing.T) {
	prev := base()
	cur := base() // agent commented, but NonAgentComments stayed 0
	if got, _ := MeaningfulChange(prev, cur); got {
		t.Errorf("agent-only comment should not alert")
	}
}

// Once CI is already failing, staying failed must not re-alert.
func TestMeaningfulChangeStaysFailed(t *testing.T) {
	prev := base()
	prev.CIStatus = "failure"
	cur := base()
	cur.CIStatus = "failure"
	if got, _ := MeaningfulChange(prev, cur); got {
		t.Errorf("CI staying failed should not re-alert")
	}
}

func TestCountNonAgentComments(t *testing.T) {
	comments := []Comment{
		{User: User{Login: "unkin-agent"}},
		{User: User{Login: "ben"}},
		{User: User{Login: "unkin-agent"}},
		{User: User{Login: "reviewer"}},
	}
	if n := countNonAgentComments(comments, "unkin-agent"); n != 2 {
		t.Errorf("countNonAgentComments = %d, want 2", n)
	}
}