"""
Workflow timeline builder for the complaint department-response flow.

Assembles a chronological list of events from ComplaintInvolvedDepartment,
ComplaintExplanation, ChampionInvestigation, InvestigationResponse,
InvestigationAnswer, and ComplaintUpdate — so the template can render
a visual timeline of the entire workflow.
"""

from datetime import datetime


def build_workflow_log(complaint):
    """Return a chronologically sorted list of workflow events for a complaint."""
    events = []

    # 1. Sent to department(s)
    for idept in complaint.involved_departments.select_related("department", "added_by").all():
        ts = idept.forwarded_at or idept.sent_at
        if ts:
            events.append({
                "type": "sent_to_dept",
                "timestamp": ts,
                "actor": idept.added_by.get_full_name() if idept.added_by else "PX Team",
                "department": idept.department.get_localized_name() if hasattr(idept.department, 'get_localized_name') else (idept.department.name if idept.department else ""),
                "is_primary": idept.is_primary,
            })

    # 2. Explanations (direct replies + investigations)
    for exp in complaint.explanations.select_related("staff", "staff__department", "requested_by").all():
        champion_name = exp.staff.get_full_name() if exp.staff else "Department"

        # Email sent timestamp
        if exp.email_sent_at:
            note = getattr(exp, "request_message", "") or ""
            events.append({
                "type": "explanation_sent",
                "timestamp": exp.email_sent_at,
                "actor": "PX Team",
                "recipient": champion_name,
                "note": note,
                "attachment_count": exp.attachments.count(),
            })

        # Investigations linked to this explanation
        investigations = list(
            exp.investigation.select_related("champion", "champion__department").all()
        )

        if investigations:
            for inv in investigations:
                inv_ts = inv.created_at
                events.append({
                    "type": "investigation_started",
                    "timestamp": inv_ts,
                    "actor": inv.champion.get_full_name() if inv.champion else champion_name,
                    "status": inv.status,
                })

                # Per-staff: questions sent + responses
                for resp in inv.responses.select_related("staff", "staff__department").all():
                    staff_name = resp.staff.get_full_name() if resp.staff else "Unknown"

                    # Questions sent to this staff
                    q_sent_ts = resp.email_sent_at or inv_ts
                    questions = list(resp.questions.order_by("order").all())
                    events.append({
                        "type": "questions_sent",
                        "timestamp": q_sent_ts,
                        "actor": inv.champion.get_full_name() if inv.champion else champion_name,
                        "staff": staff_name,
                        "question_count": len(questions),
                        "questions": [
                            {"text": q.question_text, "type": q.question_type}
                            for q in questions
                        ],
                    })

                    # Staff responded
                    if resp.is_completed and resp.completed_at:
                        qa_pairs = []
                        for ans in resp.answers.select_related("question").all():
                            qa_pairs.append({
                                "question": ans.question.question_text,
                                "question_type": ans.question.question_type,
                                "answer": ans.answer_text,
                            })
                        events.append({
                            "type": "staff_responded",
                            "timestamp": resp.completed_at,
                            "actor": staff_name,
                            "investigator": inv.champion.get_full_name() if inv.champion else "Department Champion",
                            "qa_pairs": qa_pairs,
                        })
                    else:
                        events.append({
                            "type": "staff_pending",
                            "timestamp": q_sent_ts,
                            "actor": staff_name,
                            "question_count": len(questions),
                        })

                # Final reply submitted
                if inv.status == "reply_submitted" and exp.responded_at:
                    events.append({
                        "type": "reply_submitted",
                        "timestamp": exp.responded_at,
                        "actor": inv.champion.get_full_name() if inv.champion else champion_name,
                        "final_reply": inv.final_reply,
                        "negligence": inv.negligence_finding,
                        "policy_issue": inv.policy_issue_finding,
                        "improvement_project": inv.requires_improvement_project,
                        "improvement_note": inv.improvement_project_note,
                        "attachment_count": exp.attachments.count(),
                    })
        else:
            # Direct reply (no investigation)
            if exp.is_used and exp.responded_at:
                events.append({
                    "type": "direct_reply",
                    "timestamp": exp.responded_at,
                    "actor": champion_name,
                    "reply": exp.explanation,
                    "attachment_count": exp.attachments.count(),
                })

    # Sort by timestamp (None timestamps go last)
    events.sort(key=lambda e: e.get("timestamp") or datetime.max)

    return events