from __future__ import annotations

import json
import os
from dataclasses import dataclass, field
from pathlib import Path
from typing import Any, Callable

from reuse_surface.establish import format_publish_check_markdown, publish_check
from reuse_surface.interactive import NonInteractiveError, prompt_batch
from reuse_surface.maintain_llm import request_maintain_patches
from reuse_surface.patches import (
    apply_patches_atomic,
    filter_auto_patches,
    patches_from_suggestions,
)
from reuse_surface.registry import load_index_at, registry_paths
from reuse_surface.registry_update import collect_deterministic_suggestions


@dataclass
class MaintainResult:
    selected_count: int = 0
    applied: list[str] = field(default_factory=list)
    skipped: int = 0
    notes: list[str] = field(default_factory=list)
    publish: dict[str, Any] | None = None
    exit_code: int = 0


def collect_capability_ids(
    repo_root: Path,
    *,
    capability_id: str | None,
    all_capabilities: bool,
) -> list[str]:
    index = load_index_at(registry_paths(repo_root)["index"])
    ids = [row["id"] for row in index.get("capabilities", [])]
    if capability_id:
        if capability_id not in ids:
            raise ValueError(f"capability not in index: {capability_id}")
        return [capability_id]
    if all_capabilities:
        return ids
    raise ValueError("specify --capability or --all")


def gather_patches(
    repo_root: Path,
    *,
    capability_ids: list[str],
    git_since: str | None,
    llm_url: str | None,
    no_llm: bool,
) -> tuple[list[dict[str, Any]], list[str]]:
    patches: list[dict[str, Any]] = []
    notes: list[str] = []

    scope_id = capability_ids[0] if len(capability_ids) == 1 else None
    suggestions = collect_deterministic_suggestions(
        repo_root,
        capability_id=scope_id,
        git_since=git_since,
    )
    patches = patches_from_suggestions(suggestions)
    if scope_id:
        patches = [
            patch
            for patch in patches
            if patch["capability_id"] == scope_id
            or patch.get("kind") == "index_updated_bump"
        ]

    if no_llm:
        return patches, notes

    try:
        for cap_id in capability_ids:
            payload = request_maintain_patches(
                repo_root,
                cap_id,
                git_since=git_since,
                llm_url=llm_url,
            )
            patches.extend(payload.get("patches", []))
            notes.extend(payload.get("notes", []))
    except ValueError as exc:
        if "LLM backend not configured" in str(exc):
            notes.append("LLM phase skipped: LLM_CONNECT_URL not set")
        else:
            notes.append(f"LLM phase skipped: {exc}")

    return patches, notes


def run_maintain(
    repo_root: Path,
    *,
    capability_id: str | None = None,
    all_capabilities: bool = False,
    git_since: str | None = None,
    llm_url: str | None = None,
    no_llm: bool = False,
    auto: bool = False,
    yes: bool = False,
    auto_confidence: str = "high",
    auto_max_delta: int = 1,
    publish: bool = False,
    raw_url: str | None = None,
    output_format: str = "markdown",
    validate_fn: Callable[[], tuple[int, list[str], list[str]]] | None = None,
) -> MaintainResult:
    if publish and not raw_url:
        raw_url = os.environ.get("REUSE_SURFACE_RAW_URL")
    if publish and not raw_url:
        raise ValueError("--publish requires --raw-url or REUSE_SURFACE_RAW_URL")

    cap_ids = collect_capability_ids(
        repo_root,
        capability_id=capability_id,
        all_capabilities=all_capabilities,
    )
    patches, notes = gather_patches(
        repo_root,
        capability_ids=cap_ids,
        git_since=git_since,
        llm_url=llm_url,
        no_llm=no_llm,
    )

    result = MaintainResult(notes=notes)

    if not patches:
        result.exit_code = 0
        if publish and raw_url:
            result.publish = publish_check(repo_root, raw_url=raw_url)
            if not result.publish["ok"]:
                result.exit_code = 1
        return result

    if auto or yes:
        selected = filter_auto_patches(
            patches,
            repo_root,
            auto_confidence=auto_confidence,
            auto_max_delta=auto_max_delta,
        )
        result.skipped = len(patches) - len(selected)
    else:
        try:
            selected = prompt_batch(
                patches,
                assume_yes=yes,
                auto_mode=False,
                emit_json=output_format == "json",
            )
            result.skipped = len(patches) - len(selected)
        except NonInteractiveError as exc:
            raise ValueError(str(exc)) from exc

    result.selected_count = len(selected)
    if not selected:
        result.exit_code = 2
        return result

    if validate_fn is None:
        raise ValueError("validate_fn is required")

    applied, code = apply_patches_atomic(repo_root, selected, validate=validate_fn)
    result.applied = applied
    result.exit_code = code

    if code == 0 and publish and raw_url:
        result.publish = publish_check(repo_root, raw_url=raw_url)
        if not result.publish["ok"]:
            result.exit_code = 1

    return result


def format_maintain_markdown(result: MaintainResult) -> str:
    lines = ["# Registry maintain session", ""]
    lines.append(f"**Selected:** {result.selected_count} patch(es)")
    lines.append(f"**Skipped:** {result.skipped}")
    lines.append(f"**Exit:** {result.exit_code}")
    if result.applied:
        lines.append("")
        lines.append("## Applied")
        for item in result.applied:
            lines.append(f"- {item}")
    if result.notes:
        lines.append("")
        lines.append("## Notes")
        for note in result.notes:
            lines.append(f"- {note}")
    if result.publish:
        lines.append("")
        lines.append(format_publish_check_markdown(result.publish).rstrip())
    return "\n".join(lines) + "\n"


def format_maintain_json(result: MaintainResult) -> str:
    return json.dumps(
        {
            "selected_count": result.selected_count,
            "skipped": result.skipped,
            "applied": result.applied,
            "notes": result.notes,
            "publish": result.publish,
            "exit_code": result.exit_code,
        },
        indent=2,
        sort_keys=True,
    )