from __future__ import annotations

from pathlib import Path
from typing import Any

import yaml
from jsonschema import Draft202012Validator

from open_reuse.registry import (
    INDEX_REQUIRED_FIELDS,
    integration_paths,
    load_index,
    load_schema,
    load_yaml,
    registry_paths,
    resolve_external_definition,
    resolve_repo_root,
)


def _format_schema_error(path: Path, error: Any) -> str:
    location = ".".join(str(part) for part in error.path) or "(root)"
    return f"{path}: schema error at {location}: {error.message}"


def validate_definition(
    path: Path,
    schema: dict[str, Any],
) -> tuple[list[str], list[str]]:
    errors: list[str] = []
    warnings: list[str] = []
    try:
        data = load_yaml(path)
    except (OSError, yaml.YAMLError, ValueError) as exc:
        return [f"{path}: failed to load YAML: {exc}"], warnings

    validator = Draft202012Validator(schema)
    schema_errors = sorted(validator.iter_errors(data), key=lambda item: list(item.path))
    if schema_errors:
        errors.extend(_format_schema_error(path, item) for item in schema_errors)
        return errors, warnings

    warnings.extend(_promotion_gate_warnings(path, data))
    return errors, warnings


def _promotion_gate_warnings(path: Path, data: dict[str, Any]) -> list[str]:
    warnings: list[str] = []
    status = data.get("status", "draft")
    maintenance = data.get("maintenance", {})

    if status == "active" and not maintenance.get("maintainers"):
        warnings.append(
            f"{path}: active integration missing maintenance.maintainers"
        )
    if status in {"registered", "active"}:
        if not data.get("boundary"):
            warnings.append(f"{path}: {status} integration missing boundary block")
        if not data.get("validation", {}).get("harness"):
            warnings.append(f"{path}: {status} integration missing validation.harness")
    return warnings


def validate_index(
    repo_root: Path,
    *,
    repos_base: Path | None,
    indexed_only: bool = False,
) -> tuple[list[str], list[str]]:
    errors: list[str] = []
    warnings: list[str] = []
    index = load_index(repo_root)
    entries = index.get("integrations", [])
    if not isinstance(entries, list):
        return ["indexes/integrations.yaml: integrations must be a list"], warnings

    seen_ids: set[str] = set()
    indexed_ids: set[str] = set()
    for row in entries:
        if not isinstance(row, dict):
            errors.append("indexes/integrations.yaml: integration row must be a mapping")
            continue

        integration_id = row.get("id")
        if not integration_id:
            errors.append("indexes/integrations.yaml: integration row missing id")
            continue
        if integration_id in seen_ids:
            errors.append(
                f"indexes/integrations.yaml: duplicate integration id '{integration_id}'"
            )
        seen_ids.add(integration_id)
        indexed_ids.add(integration_id)

        for field in INDEX_REQUIRED_FIELDS:
            if field not in row:
                errors.append(
                    f"indexes/integrations.yaml: '{integration_id}' missing required field '{field}'"
                )

        upstream = row.get("upstream")
        if upstream is not None and not isinstance(upstream, dict):
            errors.append(
                f"indexes/integrations.yaml: '{integration_id}' upstream must be a mapping"
            )
        elif isinstance(upstream, dict) and "name" not in upstream:
            errors.append(
                f"indexes/integrations.yaml: '{integration_id}' upstream missing name"
            )

        repo_slug = row.get("repo")
        rel_path = row.get("path")
        if not repo_slug or not rel_path:
            continue

        definition_path = resolve_external_definition(repo_slug, rel_path, repos_base)
        if definition_path is None:
            if repos_base is None:
                warnings.append(
                    f"indexes/integrations.yaml: '{integration_id}' definition not checked "
                    f"(pass --repos-base to verify {repo_slug}/{rel_path})"
                )
            else:
                warnings.append(
                    f"indexes/integrations.yaml: '{integration_id}' definition not found at "
                    f"{repos_base / repo_slug / rel_path}"
                )
            continue

        try:
            definition = load_yaml(definition_path)
        except (OSError, yaml.YAMLError, ValueError) as exc:
            errors.append(
                f"indexes/integrations.yaml: '{integration_id}' definition load failed: {exc}"
            )
            continue

        if definition.get("id") != integration_id:
            errors.append(
                f"indexes/integrations.yaml: '{integration_id}' id mismatch in "
                f"{definition_path} (found '{definition.get('id')}')"
            )
        index_mode = row.get("reuse_mode")
        definition_mode = definition.get("reuse", {}).get("primary_reuse_mode")
        if index_mode and definition_mode and index_mode != definition_mode:
            errors.append(
                f"indexes/integrations.yaml: '{integration_id}' reuse_mode '{index_mode}' "
                f"does not match definition '{definition_mode}'"
            )

    if not indexed_only:
        local_paths = integration_paths(repo_root)
        for path in local_paths:
            try:
                definition = load_yaml(path)
            except (OSError, yaml.YAMLError, ValueError) as exc:
                errors.append(f"{path}: failed to load local definition: {exc}")
                continue
            integration_id = definition.get("id")
            if integration_id and integration_id not in indexed_ids:
                warnings.append(
                    f"{path}: local definition '{integration_id}' missing index row"
                )

    return errors, warnings


def run_validate(
    *,
    root: Path | None,
    targets: list[Path] | None,
    repos_base: Path | None,
    fail_on_warnings: bool,
    check_index: bool,
    indexed_only: bool,
) -> int:
    repo_root = resolve_repo_root(root)
    schema = load_schema(repo_root)
    errors: list[str] = []
    warnings: list[str] = []

    definition_paths = integration_paths(repo_root, targets)
    if targets is None and not definition_paths and not check_index:
        definition_paths = []

    for path in definition_paths:
        file_errors, file_warnings = validate_definition(path, schema)
        errors.extend(file_errors)
        warnings.extend(file_warnings)

    if check_index:
        index_errors, index_warnings = validate_index(
            repo_root,
            repos_base=repos_base,
            indexed_only=indexed_only,
        )
        errors.extend(index_errors)
        warnings.extend(index_warnings)

    for warning in warnings:
        print(f"warning: {warning}")
    for error in errors:
        print(f"error: {error}")

    if errors:
        return 1
    if fail_on_warnings and warnings:
        return 1
    return 0