package config

import (
	"fmt"

	"github.com/router-for-me/CLIProxyAPI/v7/internal/credentialweight"
	"gopkg.in/yaml.v3"
)

// MaxCredentialWeight is the largest positive credential routing weight.
const MaxCredentialWeight = int(credentialweight.Max)

// ValidateCredentialWeight validates one optional config credential weight.
func ValidateCredentialWeight(weight *int) error {
	if weight == nil {
		return nil
	}
	_, errNormalize := credentialweight.Normalize(int64(*weight))
	return errNormalize
}

func validateCredentialWeightYAML(data []byte) error {
	var document yaml.Node
	if errUnmarshal := yaml.Unmarshal(data, &document); errUnmarshal != nil {
		return nil
	}
	if len(document.Content) == 0 {
		return nil
	}
	root := document.Content[0]
	families := map[string]struct{}{
		"gemini-api-key": {}, "interactions-api-key": {}, "claude-api-key": {},
		"vertex-api-key": {}, "codex-api-key": {}, "xai-api-key": {},
	}
	for index := 0; root != nil && root.Kind == yaml.MappingNode && index+1 < len(root.Content); index += 2 {
		name := root.Content[index].Value
		value := root.Content[index+1]
		if _, ok := families[name]; ok {
			if errValidate := validateWeightSequenceNode(value, name); errValidate != nil {
				return errValidate
			}
			continue
		}
		if name == "openai-compatibility" {
			if errValidate := validateOpenAICompatibilityWeightNodes(value); errValidate != nil {
				return errValidate
			}
		}
	}
	return nil
}

func validateWeightSequenceNode(sequence *yaml.Node, path string) error {
	if sequence == nil || sequence.Kind != yaml.SequenceNode {
		return nil
	}
	for index, item := range sequence.Content {
		if errValidate := validateWeightMappingNode(item, fmt.Sprintf("%s[%d]", path, index)); errValidate != nil {
			return errValidate
		}
	}
	return nil
}

func validateWeightMappingNode(mapping *yaml.Node, path string) error {
	if mapping == nil || mapping.Kind != yaml.MappingNode {
		return nil
	}
	for index := 0; index+1 < len(mapping.Content); index += 2 {
		if mapping.Content[index].Value != "weight" {
			continue
		}
		value := mapping.Content[index+1]
		if value.Kind != yaml.ScalarNode || value.Tag != "!!int" {
			return fmt.Errorf("%s.weight: weight must be an integer", path)
		}
		var weight int64
		if errDecode := value.Decode(&weight); errDecode != nil {
			return fmt.Errorf("%s.weight: weight must be an integer", path)
		}
		if _, errNormalize := credentialweight.Normalize(weight); errNormalize != nil {
			return fmt.Errorf("%s.weight: %w", path, errNormalize)
		}
	}
	return nil
}

func validateOpenAICompatibilityWeightNodes(sequence *yaml.Node) error {
	if sequence == nil || sequence.Kind != yaml.SequenceNode {
		return nil
	}
	for providerIndex, provider := range sequence.Content {
		if provider == nil || provider.Kind != yaml.MappingNode {
			continue
		}
		for index := 0; index+1 < len(provider.Content); index += 2 {
			if provider.Content[index].Value != "api-key-entries" {
				continue
			}
			path := fmt.Sprintf("openai-compatibility[%d].api-key-entries", providerIndex)
			if errValidate := validateWeightSequenceNode(provider.Content[index+1], path); errValidate != nil {
				return errValidate
			}
		}
	}
	return nil
}

// ValidateCredentialWeights validates weights for every API-key family.
func (cfg *Config) ValidateCredentialWeights() error {
	if cfg == nil {
		return nil
	}
	for index := range cfg.GeminiKey {
		if errValidate := ValidateCredentialWeight(cfg.GeminiKey[index].Weight); errValidate != nil {
			return fmt.Errorf("gemini-api-key[%d].weight: %w", index, errValidate)
		}
	}
	for index := range cfg.InteractionsKey {
		if errValidate := ValidateCredentialWeight(cfg.InteractionsKey[index].Weight); errValidate != nil {
			return fmt.Errorf("interactions-api-key[%d].weight: %w", index, errValidate)
		}
	}
	for index := range cfg.ClaudeKey {
		if errValidate := ValidateCredentialWeight(cfg.ClaudeKey[index].Weight); errValidate != nil {
			return fmt.Errorf("claude-api-key[%d].weight: %w", index, errValidate)
		}
	}
	for index := range cfg.VertexCompatAPIKey {
		if errValidate := ValidateCredentialWeight(cfg.VertexCompatAPIKey[index].Weight); errValidate != nil {
			return fmt.Errorf("vertex-api-key[%d].weight: %w", index, errValidate)
		}
	}
	for index := range cfg.CodexKey {
		if errValidate := ValidateCredentialWeight(cfg.CodexKey[index].Weight); errValidate != nil {
			return fmt.Errorf("codex-api-key[%d].weight: %w", index, errValidate)
		}
	}
	for index := range cfg.XAIKey {
		if errValidate := ValidateCredentialWeight(cfg.XAIKey[index].Weight); errValidate != nil {
			return fmt.Errorf("xai-api-key[%d].weight: %w", index, errValidate)
		}
	}
	for providerIndex := range cfg.OpenAICompatibility {
		for keyIndex := range cfg.OpenAICompatibility[providerIndex].APIKeyEntries {
			weight := cfg.OpenAICompatibility[providerIndex].APIKeyEntries[keyIndex].Weight
			if errValidate := ValidateCredentialWeight(weight); errValidate != nil {
				return fmt.Errorf("openai-compatibility[%d].api-key-entries[%d].weight: %w", providerIndex, keyIndex, errValidate)
			}
		}
	}
	return nil
}