"""Chat-style Gradio UI for a locally-running ``opencode serve``.

Prereq: ``opencode serve`` on http://127.0.0.1:4096.

Run:
    uv run --with gradio --with httpx python local_ui.py
"""

from __future__ import annotations

import html as _html
import json
import threading
import time
from typing import Any, Generator

import gradio as gr
import httpx


BASE = "http://127.0.0.1:4096"


# ── HTTP helpers ────────────────────────────────────────────────────────────


def _get(path: str, **kw) -> Any:
    r = httpx.get(f"{BASE}{path}", timeout=15, **kw)
    r.raise_for_status()
    return r.json()


def _create_session() -> str:
    return httpx.post(f"{BASE}/session", json={"title": "gradio"}, timeout=15).json()["id"]


def _fire_async(sid: str, prompt: str) -> None:
    httpx.post(
        f"{BASE}/session/{sid}/prompt_async",
        json={"parts": [{"type": "text", "text": prompt}]},
        timeout=30,
    ).raise_for_status()


def _abort(sid: str) -> None:
    try:
        httpx.post(f"{BASE}/session/{sid}/abort", timeout=10)
    except Exception:
        pass


def _session_diff(sid: str) -> list[dict]:
    try:
        return _get(f"/session/{sid}/diff") or []
    except Exception:
        return []


def _session_todo(sid: str) -> list[dict]:
    try:
        return _get(f"/session/{sid}/todo") or []
    except Exception:
        return []


# ── Server identity ────────────────────────────────────────────────────────


def _banner() -> str:
    try:
        h = _get("/global/health")
        c = _get("/config")
        prov = (c.get("provider") or {}).get("vllm") or {}
        opts = prov.get("options") or {}
        model = c.get("model") or "?"
        base_url = opts.get("baseURL") or "?"
        limit = next(iter(prov.get("models", {}).values()), {}).get("limit") or {}
        try:
            tools = _get("/experimental/tool/ids") or []
        except Exception:
            tools = []
        tool_line = (
            f"<div class='tools'>tools: {', '.join(_esc(t) for t in tools)}</div>"
            if tools else ""
        )
        return (
            "<div class='banner'>"
            f"<span class='chip ok'>opencode v{_esc(h.get('version','?'))}</span> "
            f"<span class='chip'>model: <code>{_esc(model)}</code></span> "
            f"<span class='chip'>baseURL: <code>{_esc(base_url)}</code></span> "
            f"<span class='chip'>ctx: <code>{limit.get('context','?')}</code></span> "
            f"<span class='chip'>out: <code>{limit.get('output','?')}</code></span>"
            f"</div>{tool_line}"
        )
    except Exception as exc:
        return f"<div class='banner'><span class='chip err'>server unreachable: {_esc(exc)}</span></div>"


# ── SSE ────────────────────────────────────────────────────────────────────


def _stream(sid_filter: str, events: list, stop: threading.Event) -> None:
    """Tail GET /event, append every frame (caller filters)."""
    try:
        with httpx.stream("GET", f"{BASE}/event", timeout=None) as r:
            for line in r.iter_lines():
                if stop.is_set():
                    return
                if not line or not line.startswith("data:"):
                    continue
                try:
                    events.append(json.loads(line[5:].strip()))
                except Exception:
                    pass
    except Exception:
        return


# ── Part + delta assembly ──────────────────────────────────────────────────


def _assemble(events: list[dict]) -> tuple[list[dict], list[str]]:
    """Reduce events to ordered parts and collect any error reasons.

    - ``message.part.updated`` is authoritative per ``part.id``.
    - ``message.part.delta`` frames for a text part whose last snapshot is
      shorter than the accumulated delta are appended live so streaming
      looks smooth.
    """
    order: list[str] = []
    latest: dict[str, dict] = {}
    deltas: dict[str, str] = {}
    errors: list[str] = []
    for ev in events:
        t = ev.get("type")
        props = ev.get("properties") or {}
        if t == "message.part.updated":
            p = props.get("part") or {}
            pid = p.get("id")
            if not pid:
                continue
            if pid not in latest:
                order.append(pid)
            latest[pid] = p
            if (p.get("state") or {}).get("status") == "error":
                err = (p.get("state") or {}).get("error") or "tool error"
                errors.append(f"{p.get('tool','?')}: {err}")
        elif t == "message.part.delta":
            p = props.get("part") or {}
            pid = p.get("partID") or p.get("id")
            if not pid:
                continue
            delta = p.get("delta") or p.get("text") or ""
            if isinstance(delta, str) and delta:
                deltas[pid] = deltas.get(pid, "") + delta
        elif t in ("error", "client.error"):
            errors.append(_esc(props.get("reason") or ev.get("reason") or "unknown"))

    # Splice in any deltas that exceed the latest snapshot (live streaming).
    parts: list[dict] = []
    for pid in order:
        p = dict(latest[pid])
        if p.get("type") == "text" and pid in deltas:
            if len(deltas[pid]) > len(p.get("text") or ""):
                p["text"] = deltas[pid]
        parts.append(p)
    return parts, errors


# ── Rendering ──────────────────────────────────────────────────────────────


def _esc(s: Any) -> str:
    return _html.escape("" if s is None else str(s))


def _cap(s: str, n: int = 6000) -> str:
    if len(s) <= n:
        return s
    return s[:n] + f"\n… ({len(s) - n} chars hidden)"


def _fmt_tool(name: str, state: dict, raw: dict) -> str:
    status = (state or {}).get("status") or "?"
    inp = (state or {}).get("input") or raw.get("input") or {}
    out = (state or {}).get("output") or raw.get("output") or ""
    badge = {"completed": "ok", "error": "err", "running": "run"}.get(status, "")

    if name == "read":
        summary = f"📖 read <code>{_esc(inp.get('filePath') or inp.get('path'))}</code>"
        body = f"<pre>{_esc(_cap(str(out)))}</pre>"
    elif name == "write":
        path = inp.get("filePath") or inp.get("path")
        content = inp.get("content") or ""
        summary = f"✍️ write <code>{_esc(path)}</code> ({len(content)} chars)"
        body = f"<pre>{_esc(_cap(content))}</pre>"
    elif name == "edit":
        path = inp.get("filePath") or inp.get("path")
        old = inp.get("oldString") or ""
        new = inp.get("newString") or ""
        summary = f"✏️ edit <code>{_esc(path)}</code>"
        body = (
            f"<div class='lbl'>- old</div><pre class='del'>{_esc(_cap(old, 3000))}</pre>"
            f"<div class='lbl'>+ new</div><pre class='add'>{_esc(_cap(new, 3000))}</pre>"
        )
        if out:
            body += f"<div class='lbl'>output</div><pre>{_esc(_cap(str(out), 2000))}</pre>"
    elif name == "bash":
        cmd = inp.get("command") or inp.get("cmd") or ""
        summary = f"⚡ bash <code>{_esc(cmd[:160])}</code>"
        body = f"<pre>{_esc(_cap(str(out)))}</pre>"
    elif name in ("glob", "find"):
        pattern = inp.get("pattern") or inp.get("query") or ""
        summary = f"🔎 {name} <code>{_esc(pattern)}</code>"
        body = f"<pre>{_esc(_cap(str(out), 4000))}</pre>"
    elif name == "grep":
        pattern = inp.get("pattern") or ""
        path = inp.get("path") or ""
        summary = f"🔎 grep <code>{_esc(pattern)}</code>" + (
            f" in <code>{_esc(path)}</code>" if path else ""
        )
        body = f"<pre>{_esc(_cap(str(out), 4000))}</pre>"
    elif name == "todowrite":
        todos = inp.get("todos") or []
        summary = f"📝 todowrite ({len(todos)} items)"
        body = "<ul>" + "".join(
            f"<li>{_todo_icon(t.get('status'))} {_esc(t.get('content'))}</li>"
            for t in todos
        ) + "</ul>"
    elif name == "task":
        desc = inp.get("description") or inp.get("prompt") or ""
        summary = f"🧩 task — {_esc(desc[:160])}"
        body = f"<pre>{_esc(_cap(str(out), 4000))}</pre>"
    elif name == "webfetch":
        summary = f"🌐 webfetch <code>{_esc(inp.get('url'))}</code>"
        body = f"<pre>{_esc(_cap(str(out), 4000))}</pre>"
    else:
        summary = f"🔧 {_esc(name)}"
        body = (
            f"<div class='lbl'>input</div><pre>{_esc(_cap(json.dumps(inp, indent=2, default=str), 4000))}</pre>"
            f"<div class='lbl'>output</div><pre>{_esc(_cap(str(out), 4000))}</pre>"
        )
    return (
        "<details class='tool' open>"
        f"<summary>{summary} <span class='badge {badge}'>{_esc(status)}</span></summary>"
        f"<div class='tbody'>{body}</div>"
        "</details>"
    )


def _todo_icon(status: str | None) -> str:
    return {"completed": "✅", "in_progress": "🔄"}.get(status or "", "⏳")


def _render_transcript(parts: list[dict], errors: list[str]) -> str:
    out: list[str] = []
    if errors:
        out.append(
            "<div class='errbox'><b>⚠️ errors</b><ul>"
            + "".join(f"<li>{_esc(e)}</li>" for e in errors[:8])
            + "</ul></div>"
        )
    if not parts:
        out.append("<div class='empty'>waiting for first part…</div>")
        return "".join(out)
    out.append("<div class='chat'>")
    for p in parts:
        t = p.get("type")
        if t == "step-start":
            out.append("<div class='step'>── new step ──</div>")
        elif t == "reasoning":
            txt = (p.get("text") or "").strip()
            if txt:
                out.append(
                    "<details class='reasoning'><summary>🧠 reasoning</summary>"
                    f"<pre>{_esc(_cap(txt, 4000))}</pre></details>"
                )
        elif t == "text":
            txt = (p.get("text") or "").strip()
            if txt:
                out.append(f"<div class='assistant'><pre>{_esc(txt)}</pre></div>")
        elif t == "tool":
            out.append(_fmt_tool(p.get("tool") or "?", p.get("state") or {}, p))
        elif t == "step-finish":
            tokens = p.get("tokens") or (p.get("state") or {}).get("tokens") or {}
            if tokens:
                out.append(f"<div class='stepfin'>tokens: {_esc(json.dumps(tokens, default=str))}</div>")
    out.append("</div>")
    return "".join(out)


def _render_todo(todos: list[dict]) -> str:
    if not todos:
        return ""
    items = "".join(
        f"<li>{_todo_icon(t.get('status'))} {_esc(t.get('content') or t.get('text',''))}</li>"
        for t in todos
    )
    return f"<div class='todostrip'><b>plan</b><ul>{items}</ul></div>"


def _render_diff(diffs: list[dict]) -> str:
    if not diffs:
        return ""
    blocks = []
    for d in diffs:
        path = d.get("path") or d.get("file") or "?"
        patch = d.get("patch") or d.get("diff") or ""
        blocks.append(
            f"<details class='diff'><summary>{_esc(path)}</summary>"
            f"<pre>{_esc(_cap(patch, 6000))}</pre></details>"
        )
    return (
        "<details class='diff-wrap' open>"
        f"<summary>📋 session diff ({len(diffs)} files)</summary>"
        f"{''.join(blocks)}</details>"
    )


# ── State ──────────────────────────────────────────────────────────────────


class _State:
    sid: str = ""  # empty → next Run creates a new session
    stop: threading.Event | None = None
    events: list[dict] = []  # reset per session
    sse_thread: threading.Thread | None = None


_STATE = _State()


def _ensure_session() -> str:
    """Create a session if none exists; reuse across runs for multi-turn."""
    if _STATE.sid:
        return _STATE.sid
    _STATE.sid = _create_session()
    _STATE.stop = threading.Event()
    _STATE.events = []
    _STATE.sse_thread = threading.Thread(
        target=_stream, args=(_STATE.sid, _STATE.events, _STATE.stop), daemon=True
    )
    _STATE.sse_thread.start()
    time.sleep(0.15)
    return _STATE.sid


def _new_session_cb() -> tuple[str, str, str, str]:
    """Tear down any existing SSE and clear state. Next Run opens a fresh session."""
    if _STATE.stop:
        _STATE.stop.set()
    if _STATE.sid:
        _abort(_STATE.sid)
    _STATE.sid = ""
    _STATE.stop = None
    _STATE.events = []
    return (
        "✨ new session — Run to start",
        "",      # transcript
        "",      # todo
        "",      # diff
    )


# ── Main ───────────────────────────────────────────────────────────────────


def run(prompt: str) -> Generator[tuple[str, str, str, str], None, None]:
    try:
        sid = _ensure_session()
    except Exception as exc:
        yield f"❌ session create failed: {exc}", "", "", ""
        return

    # Snapshot the event index BEFORE firing — "idle for THIS turn" must be
    # scoped to events that arrive after the prompt is sent, otherwise the
    # idle frame from the previous turn fires the break immediately.
    turn_start = len(_STATE.events)

    try:
        _fire_async(sid, prompt)
    except Exception as exc:
        yield f"❌ prompt failed: {exc}", "", "", ""
        return

    t0 = time.time()
    last_todo_refresh = 0.0
    todos: list[dict] = []

    while time.time() - t0 < 600:
        new_events = _STATE.events[turn_start:]
        idle = any(e.get("type") in ("session.idle", "idle") for e in new_events)
        parts, errors = _assemble(_STATE.events)

        if time.time() - last_todo_refresh > 3.0:
            todos = _session_todo(sid)
            last_todo_refresh = time.time()

        status = (
            f"{'✅ idle' if idle else '⚡ running'} · "
            f"session <code>{sid[:18]}…</code> · "
            f"{time.time()-t0:.1f}s · {len(parts)} parts · {len(_STATE.events)} events"
        )

        diff_html = ""
        if idle:
            diff_html = _render_diff(_session_diff(sid))

        yield status, _render_transcript(parts, errors), _render_todo(todos), diff_html

        if idle:
            break
        time.sleep(0.4)


def abort_cb() -> str:
    if _STATE.sid:
        _abort(_STATE.sid)
    # leave SSE open so user sees the abort-related events; actual teardown on new session
    return "⏹ aborted (session kept — click New session to clear)"


def refresh_banner() -> str:
    return _banner()


# ── CSS ────────────────────────────────────────────────────────────────────

_CSS = """
.banner { margin:4px 0 2px; }
.tools { font-size:11px; color:#888; margin:2px 0 8px; }
.chip { display:inline-block; padding:2px 8px; margin:2px; border-radius:10px;
        background:#2b2d31; color:#ddd; font-size:12px; }
.chip.ok  { background:#1f6f43; }
.chip.err { background:#7a1e1e; }
.chip code { background:transparent; color:#9ad; }
.errbox { background:#2a1414; border:1px solid #7a1e1e; border-radius:6px;
          padding:6px 10px; margin:6px 0; color:#f88; font-size:13px; }
.errbox ul { margin:2px 0 0 18px; }
.chat { font-size:14px; }
.assistant pre { background:#0e1013; padding:10px; border-radius:8px;
                 white-space:pre-wrap; color:#eee; margin:6px 0; }
.reasoning { opacity:0.8; margin:4px 0; }
.reasoning pre { background:#0a0b0d; color:#aab; padding:8px; white-space:pre-wrap; }
.tool { border:1px solid #2a2f3a; border-radius:8px; padding:6px 10px;
        margin:6px 0; background:#12161c; }
.tool summary { cursor:pointer; color:#ddd; }
.tool code { background:#222; color:#9cf; padding:1px 4px; border-radius:3px; }
.tbody { margin-top:6px; }
.tbody pre { background:#0a0b0d; padding:8px; border-radius:4px;
             white-space:pre-wrap; max-height:400px; overflow:auto;
             font-size:12px; color:#ddd; margin:2px 0; }
.tbody pre.add { border-left:3px solid #2e6; }
.tbody pre.del { border-left:3px solid #e53; }
.tbody .lbl { color:#888; font-size:11px; margin-top:6px; }
.badge { padding:1px 6px; border-radius:8px; font-size:11px;
         background:#333; color:#ddd; }
.badge.ok { background:#1f6f43; color:white; }
.badge.err { background:#7a1e1e; color:white; }
.badge.run { background:#7a5c1e; color:white; }
.step { color:#555; text-align:center; margin:10px 0; font-size:11px; }
.stepfin { color:#666; font-size:11px; margin:4px 0 12px; }
.empty { color:#666; font-style:italic; padding:12px; }
.todostrip { background:#14181e; border:1px solid #2a2f3a; border-radius:6px;
             padding:6px 10px; margin:6px 0; font-size:13px; }
.todostrip ul { margin:4px 0 0 18px; }
.diff-wrap { margin:8px 0; }
.diff summary { cursor:pointer; color:#9ad; font-family:monospace; }
.diff pre { background:#0a0b0d; padding:8px; border-radius:4px;
            white-space:pre; font-size:12px; color:#ddd; overflow:auto; }
"""


# ── Layout ─────────────────────────────────────────────────────────────────


with gr.Blocks(title="opencode serve", css=_CSS) as demo:
    banner_html = gr.HTML(value="_(loading…)_")
    status_md = gr.Markdown()
    todo_html = gr.HTML()
    transcript_html = gr.HTML(value="<div class='empty'>run a prompt to start</div>")
    diff_html = gr.HTML()

    with gr.Row():
        prompt = gr.Textbox(
            label="Prompt",
            value="Write fizzbuzz.py that prints FizzBuzz for 1..15 and run it.",
            lines=3,
            scale=5,
        )
        run_btn = gr.Button("▶ Run", variant="primary", scale=1)
        with gr.Column(scale=1, min_width=120):
            abort_btn = gr.Button("⏹ Abort", variant="stop")
            new_btn = gr.Button("✨ New session")

    run_btn.click(
        run,
        inputs=[prompt],
        outputs=[status_md, transcript_html, todo_html, diff_html],
    )
    abort_btn.click(abort_cb, outputs=[status_md])
    new_btn.click(
        _new_session_cb,
        outputs=[status_md, transcript_html, todo_html, diff_html],
    )
    demo.load(refresh_banner, outputs=[banner_html])


if __name__ == "__main__":
    import os

    demo.queue().launch(
        server_name="0.0.0.0",
        server_port=int(os.environ.get("GRADIO_PORT", "7861")),
        share=True,
        show_error=True,
    )