from __future__ import annotations

import argparse
import json
import sys
from pathlib import Path
from typing import Any

import yaml
from jsonschema import Draft202012Validator

from reuse_surface.catalog import write_catalog
from reuse_surface.overlaps import find_overlaps
from reuse_surface.registry import (
    ROOT,
    capability_paths,
    level_at_least,
    load_index,
    load_schema,
    parse_front_matter,
    parse_vector,
)


def _check_index_drift(entry_paths: list[Path], index: dict[str, Any]) -> list[str]:
    warnings: list[str] = []
    indexed_paths = {item["path"] for item in index.get("capabilities", [])}
    file_paths = {str(path.relative_to(ROOT)) for path in entry_paths}
    for path in sorted(file_paths - indexed_paths):
        warnings.append(f"index drift: entry file not indexed: {path}")
    for path in sorted(indexed_paths - file_paths):
        warnings.append(f"index drift: index references missing file: {path}")
    return warnings


def cmd_validate(args: argparse.Namespace) -> int:
    schema = load_schema()
    validator = Draft202012Validator(schema)
    target = Path(args.path) if args.path else None
    paths = capability_paths(target)
    errors: list[str] = []
    warnings: list[str] = []

    for path in paths:
        try:
            data = parse_front_matter(path)
        except ValueError as exc:
            errors.append(str(exc))
            continue
        for error in sorted(validator.iter_errors(data), key=lambda e: e.path):
            location = ".".join(str(part) for part in error.path) or "<root>"
            errors.append(f"{path}: {location}: {error.message}")

    if not target:
        index = load_index()
        warnings.extend(_check_index_drift(paths, index))

    for warning in warnings:
        print(f"warning: {warning}", file=sys.stderr)
    for error in errors:
        print(f"error: {error}", file=sys.stderr)

    if errors:
        return 1
    print(f"ok: validated {len(paths)} capability entr{'y' if len(paths) == 1 else 'ies'}")
    return 0


def _matches_query(item: dict[str, Any], args: argparse.Namespace) -> bool:
    vector = parse_vector(item["vector"])
    if args.discovery_min and not level_at_least(
        "discovery", vector["discovery"], args.discovery_min
    ):
        return False
    if args.availability_min and not level_at_least(
        "availability", vector["availability"], args.availability_min
    ):
        return False
    if args.domain and item.get("domain") != args.domain:
        return False
    if args.tag and args.tag not in item.get("tags", []):
        return False
    if args.consumption_mode:
        modes = [mode.lower() for mode in item.get("consumption_modes", [])]
        if args.consumption_mode.lower() not in modes:
            return False
    if args.keyword:
        haystack = " ".join(
            [
                item.get("id", ""),
                item.get("name", ""),
                item.get("summary", ""),
                " ".join(item.get("tags", [])),
            ]
        ).lower()
        if args.keyword.lower() not in haystack:
            return False
    return True


def cmd_query(args: argparse.Namespace) -> int:
    index = load_index()
    matches = [
        item for item in index.get("capabilities", []) if _matches_query(item, args)
    ]
    if not matches:
        print("no matches")
        return 0
    for item in matches:
        print(
            f"{item['id']}  {item['vector']}  {item['path']}\n"
            f"  {item['summary']}"
        )
    print(f"\n{len(matches)} match{'es' if len(matches) != 1 else ''}")
    return 0


def _load_indexed_entries() -> list[tuple[dict[str, Any], dict[str, Any]]]:
    index = load_index()
    indexed_entries: list[tuple[dict[str, Any], dict[str, Any]]] = []
    for item in index.get("capabilities", []):
        path = ROOT / item["path"]
        indexed_entries.append((item, parse_front_matter(path)))
    return indexed_entries


def cmd_overlaps(args: argparse.Namespace) -> int:
    indexed_entries = _load_indexed_entries()
    candidates = find_overlaps(indexed_entries, threshold=args.threshold)
    if not candidates:
        print("no overlap candidates")
        return 0
    for candidate in candidates:
        reasons = "; ".join(candidate.reasons)
        print(
            f"{candidate.left_id} <> {candidate.right_id}  "
            f"score={candidate.score:.2f}  {reasons}"
        )
    print(f"\n{len(candidates)} candidate{'s' if len(candidates) != 1 else ''}")
    return 0


def cmd_catalog(args: argparse.Namespace) -> int:
    index = load_index()
    indexed_entries = _load_indexed_entries()
    md_path, html_path = write_catalog(index, indexed_entries)
    print(f"ok: wrote {md_path.relative_to(ROOT)}")
    print(f"ok: wrote {html_path.relative_to(ROOT)}")
    return 0


def cmd_export(args: argparse.Namespace) -> int:
    index = load_index()
    bundle: dict[str, Any] = {
        "version": index.get("version", 1),
        "domain": index.get("domain"),
        "updated": index.get("updated"),
        "capabilities": [],
    }
    errors: list[str] = []

    for item in index.get("capabilities", []):
        path = ROOT / item["path"]
        try:
            front_matter = parse_front_matter(path)
        except ValueError as exc:
            errors.append(str(exc))
            continue
        bundle["capabilities"].append(
            {
                "index": item,
                "entry": front_matter,
            }
        )

    if errors:
        for error in errors:
            print(f"error: {error}", file=sys.stderr)
        return 1

    if args.format == "json":
        print(json.dumps(bundle, indent=2, sort_keys=True))
    else:
        print(yaml.safe_dump(bundle, sort_keys=False))
    print(
        f"# exported {len(bundle['capabilities'])} capabilities",
        file=sys.stderr,
    )
    return 0


def main(argv: list[str] | None = None) -> int:
    parser = argparse.ArgumentParser(prog="reuse-surface")
    subparsers = parser.add_subparsers(dest="command", required=True)

    validate = subparsers.add_parser("validate", help="validate capability entries")
    validate.add_argument(
        "path",
        nargs="?",
        help="optional capability markdown file; defaults to all entries",
    )
    validate.set_defaults(func=cmd_validate)

    query = subparsers.add_parser("query", help="query capability index")
    query.add_argument("--discovery-min")
    query.add_argument("--availability-min")
    query.add_argument("--domain")
    query.add_argument("--tag")
    query.add_argument("--consumption-mode")
    query.add_argument("--keyword")
    query.set_defaults(func=cmd_query)

    export = subparsers.add_parser("export", help="export registry bundle")
    export.add_argument(
        "--format",
        choices=["yaml", "json"],
        default="yaml",
    )
    export.set_defaults(func=cmd_export)

    overlaps = subparsers.add_parser(
        "overlaps", help="detect potential duplicate capabilities"
    )
    overlaps.add_argument(
        "--threshold",
        type=float,
        default=0.28,
        help="token similarity threshold (0-1)",
    )
    overlaps.set_defaults(func=cmd_overlaps)

    catalog = subparsers.add_parser(
        "catalog", help="generate human-readable capability catalog"
    )
    catalog.set_defaults(func=cmd_catalog)

    args = parser.parse_args(argv)
    return args.func(args)


if __name__ == "__main__":
    raise SystemExit(main())