"""HTML rendering for Phase 1 Traffic-Control View (#640)."""

from __future__ import annotations

from html import escape
from typing import Sequence

from webui.layout import render_page
from webui.traffic_loader import TrafficItem, TrafficSnapshot


def _render_badges(badges: Sequence[str]) -> str:
    if not badges:
        return ""
    out = []
    for b in badges:
        cls = "badge"
        b_lower = b.lower()
        if "blocked" in b_lower or "unmet" in b_lower:
            cls += " badge-blocked"
        elif "claimed" in b_lower or "in-progress" in b_lower or "leased" in b_lower:
            cls += " badge-claimed"
        elif "review" in b_lower or "ready" in b_lower:
            cls += " badge-in-review"
        elif "duplicate" in b_lower:
            cls += " badge-duplicate"
        elif "stale" in b_lower:
            cls += " badge-stale"
        out.append(f'<span class="{cls}">{escape(b)}</span>')
    return f'<div class="badges">{"".join(out)}</div>'


def _render_traffic_item_row(item: TrafficItem) -> str:
    kind_label = escape(item.kind.upper())
    num_str = f"#{item.number}"
    title_str = escape(item.title)
    role_str = escape(item.expected_role)
    badges_html = _render_badges(item.badges)

    reason_html = ""
    if item.block_reason:
        reason_html = f'<div class="muted" style="font-size:0.82rem; margin-top:0.2rem;"><strong>Blocker:</strong> {escape(item.block_reason)}</div>'

    lease_html = ""
    if item.lease_info:
        owner = escape(str(item.lease_info.get("session_id") or item.lease_info.get("reviewer_identity") or "active worker"))
        lease_html = f'<div class="muted" style="font-size:0.82rem; margin-top:0.2rem;"><strong>Lease:</strong> {owner}</div>'

    return f"""<tr>
  <td><code>{kind_label} {num_str}</code></td>
  <td>
    <div><strong>{title_str}</strong> {badges_html}</div>
    {reason_html}
    {lease_html}
  </td>
  <td><code>{role_str}</code></td>
</tr>"""


def _render_traffic_table(items: Sequence[TrafficItem], empty_message: str) -> str:
    if not items:
        return f'<p class="muted">{escape(empty_message)}</p>'

    rows = "".join(_render_traffic_item_row(item) for item in items)
    return f"""<table class="registry">
  <thead>
    <tr>
      <th style="width: 15%;">Item</th>
      <th style="width: 65%;">Title & Details</th>
      <th style="width: 20%;">Next Role</th>
    </tr>
  </thead>
  <tbody>
    {rows}
  </tbody>
</table>"""


def _render_next_roles(next_roles: Sequence[dict]) -> str:
    if not next_roles:
        return ""

    cards = []
    for r in next_roles:
        role = escape(r.get("role", "unknown"))
        status = r.get("status", "idle")
        prompt = escape(r.get("prompt", ""))

        status_cls = "badge-health-ok" if status == "safe" else ("badge-blocked" if "blocked" in status else "badge-health-skipped")
        cards.append(f"""<div class="health-card" style="margin-bottom:0.75rem;">
  <div style="display:flex; justify-content:space-between; align-items:center;">
    <h3>Role: <code>{role}</code></h3>
    <span class="badge {status_cls}">status: {escape(status)}</span>
  </div>
  <p class="meta" style="margin:0.35rem 0 0;">{prompt}</p>
</div>""")

    return f"""<div style="margin: 1.5rem 0;">
  <h3>Next Safe Role Actions</h3>
  {"".join(cards)}
</div>"""


def render_traffic_page(snapshot: TrafficSnapshot) -> str:
    """Render the full HTML view for workflow traffic control."""
    if snapshot.fetch_error:
        body = f"""<h2>Workflow Traffic Control</h2>
<p class="meta">Repository: <code>{escape(snapshot.repo_label)}</code></p>
<div class="health-card health-stale">
  <h3>Traffic data unavailable</h3>
  <p class="health-headline">{escape(snapshot.fetch_error)}</p>
  <p class="muted">Fail closed: traffic state cannot be established cleanly. Check credentials or remote connectivity.</p>
</div>"""
        return render_page(title="Traffic Control", body_html=body)

    runnable_count = len(snapshot.runnable)
    leased_count = len(snapshot.leased)
    blocked_count = len(snapshot.blocked)
    controller_count = len(snapshot.needs_controller)
    terminal_count = len(snapshot.terminal_complete)

    summary_bar = f"""<div class="health-card" style="display:flex; flex-wrap:wrap; gap:1rem; align-items:center;">
  <div><strong>Runnable:</strong> <span class="badge badge-health-ok">{runnable_count}</span></div>
  <div><strong>Leased:</strong> <span class="badge badge-claimed">{leased_count}</span></div>
  <div><strong>Blocked:</strong> <span class="badge badge-blocked">{blocked_count}</span></div>
  <div><strong>Needs Controller:</strong> <span class="badge badge-duplicate">{controller_count}</span></div>
  <div><strong>Terminal Complete:</strong> <span class="badge badge-stale">{terminal_count}</span></div>
</div>"""

    next_roles_html = _render_next_roles(snapshot.next_roles)

    sections_html = f"""
<div class="prompt-card">
  <h3>1. Runnable Lanes (Ready for Allocation)</h3>
  <p class="muted">Safe work items with no unmet dependencies or active leases. Safe for allocation.</p>
  {_render_traffic_table(snapshot.runnable, "No runnable items ready for allocation.")}
</div>

<div class="prompt-card">
  <h3>2. In-Progress Work (Active Leases)</h3>
  <p class="muted">Work items currently leased and actively being worked by an assigned role session.</p>
  {_render_traffic_table(snapshot.leased, "No active leases in flight.")}
</div>

<div class="prompt-card">
  <h3>3. Blocked Items (Dependencies / Locks)</h3>
  <p class="muted">Items blocked by unmet dependency issues, a missing head pin, a merge conflict, or an active terminal review lock. Items labelled status:blocked route to section 4. Never presented as safe.</p>
  {_render_traffic_table(snapshot.blocked, "No blocked items.")}
</div>

<div class="prompt-card">
  <h3>4. Needs Controller Intervention</h3>
  <p class="muted">Items requiring controller routing, diagnosis, or cross-role assignment.</p>
  {_render_traffic_table(snapshot.needs_controller, "No items requiring controller intervention.")}
</div>

<div class="prompt-card">
  <h3>5. Terminal / Complete Candidates</h3>
  <p class="muted">Items ready for terminal reconciliation or post-merge worktree cleanup.</p>
  {_render_traffic_table(snapshot.terminal_complete, "No terminal complete candidates.")}
</div>
"""

    body = f"""<h2>Workflow Traffic Control</h2>
<p class="meta">Repository: <code>{escape(snapshot.repo_label)}</code></p>
{summary_bar}
{next_roles_html}
{sections_html}"""

    return render_page(title="Traffic Control", body_html=body)