package engine

import (
	"bytes"

	"gitea.maximumdirect.net/eric/ConfigKit/internal/document"
	yamladapter "gitea.maximumdirect.net/eric/ConfigKit/internal/yaml"
)

const (
	maxDocumentDepth = 256
	maxDocumentNodes = 1_000_000
)

type parseLimits struct {
	source   sourceLimits
	document yamladapter.Limits
}

func defaultParseLimits() parseLimits {
	return parseLimits{
		source: defaultSourceLimits(),
		document: yamladapter.Limits{
			Depth: maxDocumentDepth,
			Nodes: maxDocumentNodes,
		},
	}
}

type parsedSource struct {
	document *document.Node
	source   *SourceInfo
	bytes    int64
}

// parserDiagnostics translates adapter issues into detached, ordered public records.
func parserDiagnostics(sourceID string, issues []yamladapter.Issue) []Diagnostic {
	diagnostics := make([]Diagnostic, len(issues))
	for index, issue := range issues {
		diagnostics[index] = Diagnostic{
			Code: Code(issue.Code), Severity: SeverityError, Message: issue.Message,
			Primary: &Location{SourceID: sourceID, Line: issue.Line, Column: issue.Column},
		}
		for _, related := range issue.Related {
			diagnostics[index].Related = append(diagnostics[index].Related, publicLocation(related))
		}
	}
	return canonicalDiagnostics(diagnostics)
}

func parseSource(source Source, sourceID string, limits parseLimits) (parsedSource, []Diagnostic) {
	read, diagnostics := readSource(source, sourceID, limits.source)
	if len(diagnostics) != 0 || read.info == nil {
		return parsedSource{source: read.info}, diagnostics
	}
	if read.document != nil {
		return parsedSource{document: read.document, source: read.info, bytes: read.bytes}, nil
	}

	root, issues := yamladapter.Parse(bytes.NewReader(read.data), sourceID, limits.document)
	if len(issues) != 0 {
		return parsedSource{source: read.info, bytes: int64(len(read.data))}, parserDiagnostics(sourceID, issues)
	}
	return parsedSource{document: root, source: read.info, bytes: int64(len(read.data))}, nil
}