package yqlib

import (
	"container/list"
	"fmt"
	"regexp"
	"strings"

	"gopkg.in/yaml.v3"
)

func getSubstituteParameters(d *dataTreeNavigator, block *ExpressionNode, context Context) (string, string, error) {
	regEx := ""
	replacementText := ""

	regExNodes, err := d.GetMatchingNodes(context.ReadOnlyClone(), block.Lhs)
	if err != nil {
		return "", "", err
	}
	if regExNodes.MatchingNodes.Front() != nil {
		regEx = regExNodes.MatchingNodes.Front().Value.(*CandidateNode).Node.Value
	}

	log.Debug("regEx %v", regEx)

	replacementNodes, err := d.GetMatchingNodes(context, block.Rhs)
	if err != nil {
		return "", "", err
	}
	if replacementNodes.MatchingNodes.Front() != nil {
		replacementText = replacementNodes.MatchingNodes.Front().Value.(*CandidateNode).Node.Value
	}

	return regEx, replacementText, nil
}

func substitute(original string, regex *regexp.Regexp, replacement string) *yaml.Node {
	replacedString := regex.ReplaceAllString(original, replacement)
	return &yaml.Node{Kind: yaml.ScalarNode, Value: replacedString, Tag: "!!str"}
}

func substituteStringOperator(d *dataTreeNavigator, context Context, expressionNode *ExpressionNode) (Context, error) {
	//rhs  block operator
	//lhs of block = regex
	//rhs of block = replacement expression
	block := expressionNode.Rhs

	regExStr, replacementText, err := getSubstituteParameters(d, block, context)

	if err != nil {
		return Context{}, err
	}

	regEx, err := regexp.Compile(regExStr)
	if err != nil {
		return Context{}, err
	}

	var results = list.New()

	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
		candidate := el.Value.(*CandidateNode)
		node := unwrapDoc(candidate.Node)
		if node.Tag != "!!str" {
			return Context{}, fmt.Errorf("cannot substitute with %v, can only substitute strings. Hint: Most often you'll want to use '|=' over '=' for this operation.", node.Tag)
		}

		targetNode := substitute(node.Value, regEx, replacementText)
		result := candidate.CreateChild(nil, targetNode)
		results.PushBack(result)
	}

	return context.ChildContext(results), nil

}

func addMatch(original []*yaml.Node, match string, offset int) []*yaml.Node {
	return append(original,
		createScalarNode("string", "string"),
		createScalarNode(match, match),
		createScalarNode("offset", "offset"),
		createScalarNode(offset, fmt.Sprintf("%v", offset)),
		createScalarNode("length", "length"),
		createScalarNode(len(match), fmt.Sprintf("%v", len(match))))
}

func match(regEx *regexp.Regexp, candidate *CandidateNode, value string, results *list.List) {
	// captures = FindAllStringSubmatch
	// FindAllStringSubmatchIndex = offset?

	//string array
	// subNames := regEx.SubexpNames()

	//array of arrays
	allMatches := regEx.FindAllStringSubmatch(value, -1)
	allIndices := regEx.FindAllStringSubmatchIndex(value, -1)

	for i, matches := range allMatches {
		capturesNode := &yaml.Node{Kind: yaml.SequenceNode}
		match, submatches := matches[0], matches[1:]
		for j, submatch := range submatches {
			captureNode := &yaml.Node{Kind: yaml.MappingNode}
			captureNode.Content = addMatch(capturesNode.Content, submatch, allIndices[i][2+j*2])
			capturesNode.Content = append(capturesNode.Content, captureNode)
		}

		node := &yaml.Node{Kind: yaml.MappingNode}
		node.Content = addMatch(node.Content, match, allIndices[i][0])
		node.Content = append(node.Content,
			createScalarNode("captures", "captures"),
			capturesNode,
		)
		results.PushBack(candidate.CreateChild(nil, node))

	}

}

func matchOperator(d *dataTreeNavigator, context Context, expressionNode *ExpressionNode) (Context, error) {
	//rhs  block operator
	//lhs of block = regex

	regExNodes, err := d.GetMatchingNodes(context.ReadOnlyClone(), expressionNode.Rhs)
	if err != nil {
		return Context{}, err
	}
	log.Debug(NodesToString(regExNodes.MatchingNodes))
	regExStr := ""
	if regExNodes.MatchingNodes.Front() != nil {
		regExStr = regExNodes.MatchingNodes.Front().Value.(*CandidateNode).Node.Value
	}
	log.Debug("regEx %v", regExStr)

	regEx, err := regexp.Compile(regExStr)
	if err != nil {
		return Context{}, err
	}

	var results = list.New()

	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
		candidate := el.Value.(*CandidateNode)
		node := unwrapDoc(candidate.Node)
		if node.Tag != "!!str" {
			return Context{}, fmt.Errorf("cannot substitute with %v, can only substitute strings. Hint: Most often you'll want to use '|=' over '=' for this operation.", node.Tag)
		}

		match(regEx, candidate, node.Value, results)
	}

	return context.ChildContext(results), nil
}

func joinStringOperator(d *dataTreeNavigator, context Context, expressionNode *ExpressionNode) (Context, error) {
	log.Debugf("-- joinStringOperator")
	joinStr := ""

	rhs, err := d.GetMatchingNodes(context.ReadOnlyClone(), expressionNode.Rhs)
	if err != nil {
		return Context{}, err
	}
	if rhs.MatchingNodes.Front() != nil {
		joinStr = rhs.MatchingNodes.Front().Value.(*CandidateNode).Node.Value
	}

	var results = list.New()

	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
		candidate := el.Value.(*CandidateNode)
		node := unwrapDoc(candidate.Node)
		if node.Kind != yaml.SequenceNode {
			return Context{}, fmt.Errorf("cannot join with %v, can only join arrays of scalars", node.Tag)
		}
		targetNode := join(node.Content, joinStr)
		result := candidate.CreateChild(nil, targetNode)
		results.PushBack(result)
	}

	return context.ChildContext(results), nil
}

func join(content []*yaml.Node, joinStr string) *yaml.Node {
	var stringsToJoin []string
	for _, node := range content {
		str := node.Value
		if node.Tag == "!!null" {
			str = ""
		}
		stringsToJoin = append(stringsToJoin, str)
	}

	return &yaml.Node{Kind: yaml.ScalarNode, Value: strings.Join(stringsToJoin, joinStr), Tag: "!!str"}
}

func splitStringOperator(d *dataTreeNavigator, context Context, expressionNode *ExpressionNode) (Context, error) {
	log.Debugf("-- splitStringOperator")
	splitStr := ""

	rhs, err := d.GetMatchingNodes(context.ReadOnlyClone(), expressionNode.Rhs)
	if err != nil {
		return Context{}, err
	}
	if rhs.MatchingNodes.Front() != nil {
		splitStr = rhs.MatchingNodes.Front().Value.(*CandidateNode).Node.Value
	}

	var results = list.New()

	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
		candidate := el.Value.(*CandidateNode)
		node := unwrapDoc(candidate.Node)
		if node.Tag == "!!null" {
			continue
		}
		if node.Tag != "!!str" {
			return Context{}, fmt.Errorf("Cannot split %v, can only split strings", node.Tag)
		}
		targetNode := split(node.Value, splitStr)
		result := candidate.CreateChild(nil, targetNode)
		results.PushBack(result)
	}

	return context.ChildContext(results), nil
}

func split(value string, spltStr string) *yaml.Node {
	var contents []*yaml.Node

	if value != "" {
		var newStrings = strings.Split(value, spltStr)
		contents = make([]*yaml.Node, len(newStrings))

		for index, str := range newStrings {
			contents[index] = &yaml.Node{Kind: yaml.ScalarNode, Tag: "!!str", Value: str}
		}
	}

	return &yaml.Node{Kind: yaml.SequenceNode, Tag: "!!seq", Content: contents}
}