"""Shared Gradio UI helpers for app.py and smolbuilder.py (CLI parity)."""
from __future__ import annotations

import asyncio
import os
from dataclasses import dataclass, field

import gradio as gr

from .rust_session import (
    RustSession,
    expand_command,
    expand_skill,
    export_transcript,
    list_background_jobs,
    list_commands,
    list_mcp,
    list_rules,
    list_skills,
    render_config,
    session_timeline,
    write_agents_md,
)


@dataclass
class UiSettings:
    workspace: str = "."
    model: str = ""
    agent: str = "build"
    mode: str = "normal"  # normal | auto | plan
    think: str = "off"
    yolo: bool = False
    fan_out: bool = False


@dataclass
class ApprovalState:
    pending_desc: str | None = None
    result: bool | None = None

    async def ask(self, desc: str) -> bool:
        self.pending_desc = desc
        self.result = None
        while self.result is None:
            await asyncio.sleep(0.15)
        approved = bool(self.result)
        self.pending_desc = None
        self.result = None
        return approved

    def approve(self, yes: bool = True) -> None:
        self.result = yes

    def deny(self) -> None:
        self.approve(False)


@dataclass
class AppSessionState:
    """Gradio gr.State payload for session + settings."""
    rust: RustSession | None = None
    settings: UiSettings = field(default_factory=UiSettings)
    approval: ApprovalState = field(default_factory=ApprovalState)
    status_msg: str = ""
    bg_jobs: str = ""


@dataclass
class SlashResult:
    reply: str = ""
    queued_task: str | None = None
    clear_chat: bool = False
    download_path: str | None = None
    toggle_sidebar: bool = False
    toggle_sidebar_view: bool = False
    open_picker: str | None = None
    cycle_mode: bool = False
    cycle_think: bool = False
    set_think: str | None = None
    show_help: bool = False
    show_whichkey: bool = False


_BUILTIN_SLASH = {
    "/help", "/new", "/sessions", "/fork", "/rename", "/export", "/stats",
    "/mcp", "/rules", "/skills", "/skill", "/commit", "/init", "/bg", "/clear",
    "/delete", "/timeline", "/mode", "/think", "/config", "/search",
    "/agents", "/models", "/themes", "/files", "/quit",
}


_ATTACH_MAX = 8192


def parse_input(
    text: str,
    *,
    workspace_files: list[str] | None = None,
    workspace: str | None = None,
    rust: RustSession | None = None,
) -> tuple[str, str | None, str | None]:
    """Parse user input. Returns (task, slash_command_result, shell_output).

    - `!cmd` runs shell directly
    - `/cmd args` returns command to dispatch
    - `@file` inlines file content into task
    """
    stripped = (text or "").strip()
    if not stripped:
        return "", None, None

    if stripped.startswith("!"):
        return "", None, stripped[1:].strip()

    if stripped.startswith("/"):
        return "", stripped, None

    task = stripped
    if "@" in task and (workspace_files or workspace):
        from .rust_session import read_workspace_file

        paths = list(workspace_files or [])
        import re

        for match in re.finditer(r"@(\S+)", task):
            path = match.group(1)
            if paths and path not in paths:
                candidates = [p for p in paths if p.endswith(path) or p == path]
                if len(candidates) == 1:
                    path = candidates[0]
                elif path not in paths:
                    continue
            ws = workspace or (rust.workspace_path if rust else ".")
            content = read_workspace_file(ws, path, max_bytes=_ATTACH_MAX, rust=rust)
            if content is not None:
                block = f"[attached: {path}]\n```\n{content}\n```"
                task = task.replace(f"@{match.group(1)}", block, 1)
    return task, None, None


def _workspace(session: AppSessionState) -> str:
    return session.settings.workspace or "."


def dispatch_slash(cmd_line: str, session: AppSessionState) -> SlashResult:
    """Handle a slash command; mirrors CLI TUI handle_slash."""
    parts = cmd_line.strip().split(maxsplit=1)
    cmd = parts[0].lower()
    args = parts[1] if len(parts) > 1 else ""
    ws = _workspace(session)

    if cmd == "/help":
        custom = list_commands(ws)
        extra = ""
        if custom:
            extra = "\n\n**Custom commands:** " + ", ".join(f"`/{n}`" for n in custom)
        return SlashResult(
            reply=(
                "**Slash commands:** `/new`, `/sessions`, `/fork`, `/rename <title>`, "
                "`/stats`, `/export [file]`, `/timeline`, `/delete`, `/mcp`, `/rules`, "
                "`/skills`, `/skill <name>`, `/commit [msg]`, `/init`, `/bg`, `/clear`, "
                "`/mode`, `/think`, `/config`, `/search`, `/files`"
                f"{extra}\n\n"
                "**Input:** `!cmd` runs shell without LLM; `@file` attaches workspace files."
            )
        )

    if cmd == "/new":
        session.rust = None
        return SlashResult(reply="Started a new session.", clear_chat=True)

    if cmd == "/sessions":
        rows = RustSession.list_sessions()
        if not rows:
            return SlashResult(reply="_No saved sessions._")
        lines = [f"- **{r['title']}** (`{r['id']}`)" for r in rows[:20]]
        return SlashResult(reply="**Sessions:**\n" + "\n".join(lines))

    if cmd == "/fork":
        if session.rust and (nid := session.rust.fork()):
            return SlashResult(reply=f"Forked session → `{nid}`")
        return SlashResult(reply="Nothing to fork yet.")

    if cmd == "/rename":
        if session.rust and args and session.rust.rename(args):
            return SlashResult(reply=f"Renamed session to **{args}**")
        return SlashResult(reply="Usage: `/rename <title>`")

    if cmd == "/stats":
        nfiles = len(session.rust.files()) if session.rust else 0
        sid = session.rust.session_id if session.rust else "(none)"
        return SlashResult(
            reply=(
                f"session `{sid}` · workspace: `{ws}` · files: {nfiles} · "
                f"agent: {session.settings.agent}"
            )
        )

    if cmd == "/export":
        sid = session.rust.session_id if session.rust else ""
        if not sid:
            return SlashResult(reply="No session to export yet.")
        try:
            path = export_transcript(sid, args or None)
            return SlashResult(
                reply=f"Exported transcript to `{path}`",
                download_path=path,
            )
        except Exception as e:
            return SlashResult(reply=f"/export failed: {e}")

    if cmd == "/mcp":
        if session.rust is None:
            return SlashResult(
                reply="_Start a task first so MCP servers are connected._"
            )
        servers = list_mcp(session.rust)
        if not servers:
            return SlashResult(
                reply=(
                    "no MCP servers connected — add `[[mcp]]` entries to "
                    "`~/.config/smolcode/config.toml` or `.smolcode/config.toml`"
                )
            )
        lines = [f"**MCP servers ({len(servers)}):**"]
        for row in servers:
            tools = row.get("tools", [])
            tlist = ", ".join(tools[:8]) if tools else "(no tools)"
            if len(tools) > 8:
                tlist += "…"
            lines.append(f"- **{row.get('server', '?')}** ({len(tools)}): {tlist}")
        return SlashResult(reply="\n".join(lines))

    if cmd == "/rules":
        rules = list_rules(ws)
        if not rules:
            return SlashResult(
                reply="no rules — add `*.md` to `.smolcode/rules/` or `~/.config/smolcode/rules/`"
            )
        lines = [f"**active rules ({len(rules)}):**"]
        for r in rules:
            desc = r.get("description", "")
            tail = f" — {desc}" if desc else ""
            lines.append(f"- `{r.get('name', '?')}` [{r.get('scope', '?')}]{tail}")
        return SlashResult(reply="\n".join(lines))

    if cmd == "/skills":
        skills = list_skills(ws)
        if not skills:
            return SlashResult(
                reply="no skills — add `<name>/SKILL.md` to `.smolcode/skills/`"
            )
        lines = [f"**skills ({len(skills)})** — run with `/skill <name>`:"]
        for s in skills:
            desc = s.get("description", "")
            tail = f" — {desc}" if desc else ""
            lines.append(f"- `{s.get('name', '?')}`{tail}")
        return SlashResult(reply="\n".join(lines))

    if cmd == "/skill":
        if not args:
            return SlashResult(reply="Usage: `/skill <name> [args]` (see `/skills`)")
        sname, _, sargs = args.partition(" ")
        sname = sname.strip()
        sargs = sargs.strip()
        expanded = expand_skill(ws, sname, sargs)
        if expanded is None:
            return SlashResult(reply=f"no skill named `{sname}` (see `/skills`)")
        return SlashResult(reply=f"Running skill **{sname}**…", queued_task=expanded)

    if cmd == "/commit":
        if args:
            task = f"Commit all current changes with git_commit using this message: {args}"
        else:
            task = (
                "Review the staged/unstaged changes with git_diff, then commit them "
                "with git_commit using a concise, descriptive message."
            )
        return SlashResult(reply="Queued git commit task…", queued_task=task)

    if cmd == "/init":
        try:
            path = write_agents_md(ws)
            return SlashResult(reply=f"wrote `{path}` (project guide for agents)")
        except Exception as e:
            return SlashResult(reply=f"/init: {e}")

    if cmd == "/bg":
        session.bg_jobs = list_background_jobs()
        return SlashResult(reply=session.bg_jobs or "_No background jobs._")

    if cmd == "/timeline":
        sid = session.rust.session_id if session.rust else ""
        if not sid:
            return SlashResult(reply="no saved session yet")
        lines = session_timeline(sid)
        return SlashResult(reply="**Timeline:**\n" + "\n".join(f"- {ln}" for ln in lines))

    if cmd == "/delete":
        removed = session.rust.delete() if session.rust else False
        session.rust = None
        msg = "deleted session; started a new one" if removed else "started a new session"
        return SlashResult(reply=msg, clear_chat=True)

    if cmd == "/clear":
        return SlashResult(reply="_Transcript cleared._", clear_chat=True)

    if cmd == "/mode":
        return SlashResult(reply="Cycling mode…", cycle_mode=True)

    if cmd == "/think":
        if args:
            return SlashResult(reply=f"think → {args}", set_think=args.split()[0].lower())
        return SlashResult(reply="Cycling think level…", cycle_think=True)

    if cmd == "/config":
        if session.rust is None:
            return SlashResult(reply="_Start a task first to view config._")
        return SlashResult(reply=f"```\n{render_config(session.rust)}\n```")

    if cmd == "/search":
        if not args:
            return SlashResult(reply="Usage: `/search <text>`")
        return SlashResult(reply=f"_Search for `{args}` runs in transcript handler._")

    if cmd == "/agents":
        return SlashResult(reply="Opening agent picker…", open_picker="agents")

    if cmd == "/models":
        return SlashResult(reply="Opening model picker…", open_picker="models")

    if cmd == "/themes":
        return SlashResult(reply="Opening theme picker…", open_picker="themes")

    if cmd == "/files":
        return SlashResult(reply="Toggling sidebar…", toggle_sidebar=True)

    if cmd == "/quit":
        return SlashResult(reply="_Use browser close to exit the web UI._")

    if cmd not in _BUILTIN_SLASH:
        name = cmd.lstrip("/")
        expanded = expand_command(ws, name, args)
        if expanded is not None:
            return SlashResult(
                reply=f"Running custom command `/{name}`…",
                queued_task=expanded,
            )

    return SlashResult(reply=f"Unknown command `{cmd}`. Try `/help`.")


def settings_from_ui(
    workspace: str,
    model: str,
    agent: str,
    mode: str,
    think: str,
    yolo: bool,
) -> UiSettings:
    y = yolo or mode == "auto"
    ag = "plan" if mode == "plan" else agent
    return UiSettings(
        workspace=workspace or ".",
        model=model or "",
        agent=ag,
        mode=mode,
        think=think,
        yolo=y,
    )


def build_settings_panel(preset_models: list[str]) -> dict:
    """Return Gradio components for the settings sidebar."""
    with gr.Accordion("⚙️ settings", open=False):
        workspace = gr.Textbox(
            value=os.environ.get("SMALLCODE_WORKSPACE", "."),
            label="workspace directory",
        )
        model = gr.Dropdown(
            choices=preset_models,
            value=preset_models[0] if preset_models else "",
            label="model",
            allow_custom_value=True,
        )
        agent = gr.Dropdown(
            choices=["build", "plan"],
            value="build",
            label="agent",
        )
        mode = gr.Radio(
            choices=["normal", "auto", "plan"],
            value="normal",
            label="mode",
        )
        think = gr.Dropdown(
            choices=["off", "low", "high", "xtra"],
            value="off",
            label="think level",
        )
        yolo = gr.Checkbox(value=False, label="yolo (auto-approve tools)")
    return {
        "workspace": workspace,
        "model": model,
        "agent": agent,
        "mode": mode,
        "think": think,
        "yolo": yolo,
    }


def file_tree_md(files: dict[str, str], selected: str | None = None) -> str:
    """Legacy flat file list (prefer engine.file_tree.build_workspace_panel)."""
    if not files:
        return "_workspace is empty_"
    lines = []
    for path in sorted(files):
        mark = " →" if path == selected else ""
        lines.append(f"- `{path}`{mark}")
    body = files.get(selected or "", "") if selected and selected in files else ""
    if body:
        lang = "python" if selected.endswith(".py") else ""
        return "\n".join(lines) + f"\n\n**`{selected}`**\n```{lang}\n{body}\n```"
    return "\n".join(lines)