"""
ifc-commit web app — FastAPI entry point.

Routes:
    GET  /            — serve index.html
    GET  /api/health  — liveness check
    POST /api/preview — fetch and parse a pipeline yaml from the forge
    POST /api/run     — clone → pipeline → commit/push, stream log lines
"""

import asyncio
import contextlib
import io
import os
import shutil
import subprocess
import tempfile
from pathlib import Path

import httpx
import ifcopenshell
from fastapi import FastAPI, HTTPException
from fastapi.responses import FileResponse, StreamingResponse

from webapp.schema import RepoRequest, EntityRequest, HistoryRequest
from webapp import forge, pipeline
from webapp.pipeline import has_runnable_ops

app = FastAPI(title="ifc-commit")


def serve():
    """Entry point for the `ifccommit-web` script."""
    import uvicorn
    uvicorn.run("webapp.main:app", host="127.0.0.1", port=8095, reload=True)

# Only one pipeline run at a time — IFC files are large and CPU-heavy
_run_lock = asyncio.Lock()

TEMPLATES_DIR = __file__.replace("main.py", "templates")


# ---------------------------------------------------------------------------
# Routes
# ---------------------------------------------------------------------------

@app.get("/", response_class=FileResponse)
async def index():
    html = Path(__file__).parent.parent / "index.html"
    if not html.exists():
        raise HTTPException(status_code=404, detail="Presentation page not built. Run: make html")
    return FileResponse(str(html), media_type="text/html")


@app.get("/app", response_class=FileResponse)
async def app_ui():
    return FileResponse(f"{TEMPLATES_DIR}/index.html", media_type="text/html")


@app.get("/research", response_class=FileResponse)
async def research():
    html = Path(__file__).parent.parent / "research.html"
    if not html.exists():
        raise HTTPException(status_code=404, detail="Research page not built. Run: make html")
    return FileResponse(str(html), media_type="text/html")


@app.get("/api/health")
async def health():
    return {"status": "ok"}


@app.post("/api/yamls")
async def yamls(body: RepoRequest):
    """List yaml pipeline files available in the yaml/ directory of the repo."""
    try:
        files = await forge.list_yaml_files(body.repo, body.branch, body.token)
    except httpx.HTTPStatusError as exc:
        status = exc.response.status_code
        if status == 404:
            raise HTTPException(404, "yaml/ directory not found in repository")
        raise HTTPException(status, f"Forge API error: {exc.response.text}")
    return {"files": files}


@app.post("/api/preview")
async def preview(body: RepoRequest):
    """Fetch a pipeline yaml from the forge and return the parsed operations list."""
    try:
        raw = await forge.get_file_content(
            body.repo, body.yaml_file, body.branch, body.token
        )
    except httpx.HTTPStatusError as exc:
        status = exc.response.status_code
        if status == 404:
            raise HTTPException(404, f"{body.yaml_file} not found in repository")
        raise HTTPException(status, f"Forge API error: {exc.response.text}")

    try:
        config = pipeline.parse_yaml(raw)
    except Exception as exc:
        raise HTTPException(422, f"Invalid {body.yaml_file}: {exc}")

    return {"operations": [op.model_dump() for op in config.operations]}


@app.post("/api/entities")
async def entities(body: EntityRequest):
    """Shallow-clone the repo and return entity names for the given IFC type."""
    loop = asyncio.get_running_loop()
    tmpdir = tempfile.mkdtemp(prefix="ifccommit_ent_")
    repo_dir = f"{tmpdir}/repo"
    try:
        await loop.run_in_executor(None, forge.clone_repo_shallow, body.repo, body.token, repo_dir)
        import ifcopenshell.util.selector
        ifc_path = os.path.join(repo_dir, body.file)
        model = ifcopenshell.open(ifc_path)
        if body.location:
            elements = ifcopenshell.util.selector.filter_elements(
                model, f'IfcElement, location = "{body.location}"'
            )
            names = sorted(e.Name for e in elements if e.Name)
        else:
            names = sorted(e.Name for e in model.by_type(body.ifc_type) if e.Name)
        return {"names": names}
    except subprocess.CalledProcessError as exc:
        raise HTTPException(500, f"Clone failed: {exc.output}")
    except Exception as exc:
        raise HTTPException(500, str(exc))
    finally:
        shutil.rmtree(tmpdir, ignore_errors=True)


@app.post("/api/ifc-history")
async def ifc_history(body: HistoryRequest):
    """Shallow-clone the repo, read ifc/history.json, and return the records."""
    import json as _json
    loop = asyncio.get_running_loop()
    tmpdir = tempfile.mkdtemp(prefix="ifccommit_hist_")
    repo_dir = f"{tmpdir}/repo"
    try:
        await loop.run_in_executor(
            None, forge.clone_repo_shallow, body.repo, body.token, repo_dir
        )
        json_path = os.path.join(repo_dir, body.file)
        if not os.path.exists(json_path):
            return {"records": [], "repo": body.repo, "branch": body.branch}
        with open(json_path) as f:
            records = _json.load(f)
        return {"records": records, "repo": body.repo, "branch": body.branch}
    except subprocess.CalledProcessError as exc:
        raise HTTPException(500, f"Clone failed: {exc.output}")
    except HTTPException:
        raise
    except Exception as exc:
        raise HTTPException(500, str(exc))
    finally:
        shutil.rmtree(tmpdir, ignore_errors=True)


@app.post("/api/run")
async def run(body: RepoRequest):
    """
    Clone the repository, run all operations from the pipeline yaml,
    commit the results, and push back to the forge.
    Streams newline-terminated log lines to the client in real time.
    """
    return StreamingResponse(_run_stream(body), media_type="text/plain")


# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------

class _LogWriter:
    """
    A file-like object that splits writes on newlines and forwards each
    complete line to a log callback. Used to capture print() from cmd_*.
    """
    def __init__(self, log_fn):
        self._log = log_fn
        self._buf = ""

    def write(self, s: str) -> None:
        self._buf += s
        while "\n" in self._buf:
            line, self._buf = self._buf.split("\n", 1)
            if line:
                self._log(line)

    def flush(self) -> None:
        if self._buf.strip():
            self._log(self._buf)
            self._buf = ""


# ---------------------------------------------------------------------------
# Streaming pipeline
# ---------------------------------------------------------------------------

async def _run_stream(body: RepoRequest):
    """Async generator that runs the full pipeline and yields log lines."""

    if _run_lock.locked():
        yield "ERROR: another run is already in progress — try again shortly\n"
        return

    async with _run_lock:
        loop = asyncio.get_running_loop()
        tmpdir = tempfile.mkdtemp(prefix="ifccommit_")
        # git clone creates its own directory — give it a path that doesn't exist yet
        repo_dir = f"{tmpdir}/repo"

        try:
            # 1. Fetch and parse pipeline yaml
            yield f"Fetching {body.yaml_file}...\n"
            try:
                raw = await forge.get_file_content(
                    body.repo, body.yaml_file, body.branch, body.token
                )
            except httpx.HTTPStatusError as exc:
                yield f"ERROR: could not fetch {body.yaml_file} ({exc.response.status_code})\n"
                return

            try:
                config = pipeline.parse_yaml(raw)
            except Exception as exc:
                yield f"ERROR: invalid {body.yaml_file} — {exc}\n"
                return

            yield f"Found {len(config.operations)} operation(s)\n"

            if not has_runnable_ops(config):
                yield "No runnable operations — load history via the panel below.\n"
                return

            # 2. Clone the repository
            yield "Cloning repository...\n"
            try:
                await loop.run_in_executor(
                    None, forge.clone_repo, body.repo, body.token, repo_dir
                )
            except subprocess.CalledProcessError as exc:
                yield f"ERROR: git clone failed\n{exc.output}\n"
                return
            yield "Clone OK\n"

            # 3. Run the pipeline (synchronous — in thread pool).
            #    Log lines AND stdout from cmd_* functions are forwarded to the
            #    client via an asyncio.Queue.
            queue: asyncio.Queue[str | None] = asyncio.Queue()

            def log(line: str) -> None:
                loop.call_soon_threadsafe(queue.put_nowait, line + "\n")

            def _run() -> bool:
                # Capture print() output from cmd_* and forward to log.
                # Safe because _run_lock ensures only one thread does this.
                writer = _LogWriter(log)
                with contextlib.redirect_stdout(writer):
                    ok = pipeline.run_pipeline(config, repo_dir, log, body.overrides, body.id_overrides, body.element_overrides, yaml_path=body.yaml_file)
                writer.flush()
                loop.call_soon_threadsafe(queue.put_nowait, None)  # sentinel
                return ok

            future = loop.run_in_executor(None, _run)

            while True:
                line = await queue.get()
                if line is None:
                    break
                yield line

            ok = await future

            if not ok:
                yield "Pipeline completed with errors — skipping commit.\n"
                return

            # 4. Commit and push results
            yield "Committing results to forge...\n"
            try:
                committed = await loop.run_in_executor(
                    None,
                    forge.commit_and_push,
                    repo_dir,
                    "chore: ifccommit pipeline results [skip ci]",
                )
            except subprocess.CalledProcessError as exc:
                yield f"ERROR: git commit/push failed\n{exc.output}\n"
                return

            if committed:
                yield "Done — results committed and pushed.\n"
            else:
                yield "Done — no changes to commit (outputs unchanged).\n"

        finally:
            shutil.rmtree(tmpdir, ignore_errors=True)