package tools

import (
	"context"
	"fmt"
	"strings"

	"github.com/korap/korap-mcp/service"
	"github.com/mark3labs/mcp-go/mcp"
	"github.com/rs/zerolog/log"
)

// MetadataTool implements the Tool interface for KorAP corpus metadata retrieval
type MetadataTool struct {
	client *service.Client
}

// NewMetadataTool creates a new metadata tool instance
func NewMetadataTool(client *service.Client) *MetadataTool {
	return &MetadataTool{
		client: client,
	}
}

// Name returns the tool name
func (m *MetadataTool) Name() string {
	return "korap_metadata"
}

// Description returns the tool description
func (m *MetadataTool) Description() string {
	return "Retrieve metadata and statistics for KorAP corpora"
}

// InputSchema returns the JSON schema for tool parameters
func (m *MetadataTool) InputSchema() map[string]interface{} {
	return map[string]interface{}{
		"type": "object",
		"properties": map[string]interface{}{
			"action": map[string]interface{}{
				"type":        "string",
				"description": "Type of metadata to retrieve: 'list' for corpus list, 'statistics' for corpus statistics",
				"enum":        []string{"list", "statistics"},
				"default":     "list",
			},
			"corpus": map[string]interface{}{
				"type":        "string",
				"description": "Virtual corpus query to filter results (optional, when not provided refers to all data available to the user)",
			},
		},
		"required": []string{"action"},
	}
}

// Execute performs the metadata retrieval operation
func (m *MetadataTool) Execute(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	log.Debug().
		Str("tool", m.Name()).
		Msg("Executing metadata tool")

	// Extract required action parameter
	action, err := request.RequireString("action")
	if err != nil {
		return nil, fmt.Errorf("action parameter is required: %w", err)
	}

	// Extract optional corpus parameter
	corpus := request.GetString("corpus", "")

	log.Debug().
		Str("action", action).
		Str("corpus", corpus).
		Msg("Parsed metadata parameters")

	// Validate parameters before authentication
	switch action {
	case "list":
		// No additional validation needed for list
	case "statistics":
		// No additional validation needed for statistics - corpus is optional
	default:
		return nil, fmt.Errorf("unknown action: %s", action)
	}

	// Check if client is available and authenticated
	if m.client == nil {
		return nil, fmt.Errorf("KorAP client not configured")
	}

	if !m.client.IsAuthenticated() {
		log.Warn().Msg("Client not authenticated, attempting authentication")
		if err := m.client.AuthenticateWithClientCredentials(ctx); err != nil {
			return nil, fmt.Errorf("authentication failed: %w", err)
		}
	}

	// Handle different actions
	switch action {
	case "list":
		return m.handleListCorpora(ctx)
	case "statistics":
		return m.handleCorpusStatistics(ctx, corpus)
	default:
		// This should never be reached due to validation above
		return nil, fmt.Errorf("unknown action: %s", action)
	}
}

// handleListCorpora retrieves and formats the list of available corpora
func (m *MetadataTool) handleListCorpora(ctx context.Context) (*mcp.CallToolResult, error) {
	log.Debug().Msg("Retrieving corpus list")

	var corpusListResp service.CorpusListResponse
	err := m.client.GetJSON(ctx, "corpus", &corpusListResp)
	if err != nil {
		log.Error().
			Err(err).
			Msg("Failed to retrieve corpus list")
		return nil, fmt.Errorf("failed to retrieve corpus list: %w", err)
	}

	log.Info().
		Int("corpus_count", len(corpusListResp.Corpora)).
		Msg("Corpus list retrieved successfully")

	result := m.formatCorpusList(&corpusListResp)
	return mcp.NewToolResultText(result), nil
}

// handleCorpusStatistics retrieves and formats statistics for a corpus query
func (m *MetadataTool) handleCorpusStatistics(ctx context.Context, corpus string) (*mcp.CallToolResult, error) {
	log.Debug().
		Str("corpus", corpus).
		Msg("Retrieving corpus statistics")

	var statsResp service.StatisticsResponse
	var endpoint string
	if corpus == "" {
		endpoint = "statistics"
	} else {
		endpoint = fmt.Sprintf("statistics?corpusQuery=%s", corpus)
	}

	err := m.client.GetJSON(ctx, endpoint, &statsResp)
	if err != nil {
		log.Error().
			Err(err).
			Str("corpus", corpus).
			Msg("Failed to retrieve corpus statistics")
		return nil, fmt.Errorf("failed to retrieve corpus statistics: %w", err)
	}

	log.Info().
		Str("corpus", corpus).
		Int("documents", statsResp.Documents).
		Int("tokens", statsResp.Tokens).
		Msg("Corpus statistics retrieved successfully")

	result := m.formatCorpusStatistics(corpus, &statsResp)
	return mcp.NewToolResultText(result), nil
}

// formatCorpusList formats the corpus list response into a readable text format
func (m *MetadataTool) formatCorpusList(response *service.CorpusListResponse) string {
	var result strings.Builder

	result.WriteString("KorAP Available Corpora\n")
	result.WriteString("=======================\n\n")

	if len(response.Corpora) == 0 {
		result.WriteString("No corpora available.\n")
		return result.String()
	}

	result.WriteString(fmt.Sprintf("Total Corpora: %d\n\n", len(response.Corpora)))

	for i, corpus := range response.Corpora {
		result.WriteString(fmt.Sprintf("%d. %s\n", i+1, corpus.Name))
		result.WriteString(fmt.Sprintf("   ID: %s\n", corpus.ID))

		if corpus.Description != "" {
			result.WriteString(fmt.Sprintf("   Description: %s\n", corpus.Description))
		}

		if corpus.Documents > 0 {
			result.WriteString(fmt.Sprintf("   Documents: %d\n", corpus.Documents))
		}

		if corpus.Tokens > 0 {
			result.WriteString(fmt.Sprintf("   Tokens: %d\n", corpus.Tokens))
		}

		if corpus.Sentences > 0 {
			result.WriteString(fmt.Sprintf("   Sentences: %d\n", corpus.Sentences))
		}

		if corpus.Paragraphs > 0 {
			result.WriteString(fmt.Sprintf("   Paragraphs: %d\n", corpus.Paragraphs))
		}

		result.WriteString("\n")
	}

	return result.String()
}

// formatCorpusStatistics formats the corpus statistics response into a readable text format
func (m *MetadataTool) formatCorpusStatistics(corpus string, response *service.StatisticsResponse) string {
	var result strings.Builder

	result.WriteString("KorAP Corpus Statistics\n")
	result.WriteString("=======================\n\n")

	if corpus == "" {
		result.WriteString("Corpus Query: (all available data)\n\n")
	} else {
		result.WriteString(fmt.Sprintf("Corpus Query: %s\n\n", corpus))
	}

	result.WriteString("Statistics:\n")
	result.WriteString("-----------\n")
	result.WriteString(fmt.Sprintf("Documents: %d\n", response.Documents))
	result.WriteString(fmt.Sprintf("Tokens: %d\n", response.Tokens))

	if response.Sentences > 0 {
		result.WriteString(fmt.Sprintf("Sentences: %d\n", response.Sentences))
	}

	if response.Paragraphs > 0 {
		result.WriteString(fmt.Sprintf("Paragraphs: %d\n", response.Paragraphs))
	}

	// Add any additional fields if present
	if len(response.Fields) > 0 {
		result.WriteString("\nAdditional Fields:\n")
		result.WriteString("------------------\n")
		for key, value := range response.Fields {
			result.WriteString(fmt.Sprintf("%s: %v\n", key, value))
		}
	}

	return result.String()
}