package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"os"
	"strings"
	"sync"
	"time"

	"gitea.r8z.us/stwhite/arxiva"
	"gitea.r8z.us/stwhite/paperformatter"
	"gitea.r8z.us/stwhite/paperprocessor"
	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"
)

type ProcessingJob struct {
	ID           string    // Unique job identifier
	Status       string    // "pending", "processing", "completed", "failed"
	StartTime    time.Time // When the job started
	Error        string    // Error message if failed
	JSONPath     string    // Path to JSON output file
	MDPath       string    // Path to Markdown output file
	MarkdownText string    // Content of markdown file when completed
}

type Server struct {
	router      *chi.Mux
	port        string
	apiEndpoint string
	jobs        map[string]*ProcessingJob // Track processing jobs
	jobsMutex   sync.RWMutex              // Protect jobs map
}

func NewServer(port string, apiEndpoint string) *Server {
	s := &Server{
		router:      chi.NewRouter(),
		port:        port,
		apiEndpoint: apiEndpoint,
		jobs:        make(map[string]*ProcessingJob),
	}

	s.setupRoutes()
	return s
}

func (s *Server) setupRoutes() {
	s.router.Use(middleware.Logger)
	s.router.Use(middleware.Recoverer)

	s.router.Post("/api/papers/search", s.handleSearch)
	s.router.Post("/api/papers/process", s.handleProcess)
	s.router.Post("/api/papers/search-process", s.handleSearchAndProcess)
	s.router.Get("/api/jobs/{jobID}", s.handleJobStatus)
}

func (s *Server) Run() error {
	addr := fmt.Sprintf(":%s", s.port)
	log.Printf("Starting server on %s", addr)
	return http.ListenAndServe(addr, s.router)
}

func (s *Server) handleSearch(w http.ResponseWriter, r *http.Request) {
	var req struct {
		StartDate  string `json:"start_date"`
		EndDate    string `json:"end_date"`
		Query      string `json:"query"`
		MaxResults int    `json:"max_results"`
	}

	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Invalid request body", http.StatusBadRequest)
		return
	}

	// Reuse existing validation
	if !IsValidDate(req.StartDate) || !IsValidDate(req.EndDate) {
		http.Error(w, "Invalid date format", http.StatusBadRequest)
		return
	}

	papers, err := arxiva.FetchPapers(req.StartDate, req.EndDate, req.Query, req.MaxResults)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	json.NewEncoder(w).Encode(papers)
}

func (s *Server) handleProcess(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Papers       []arxiva.Paper `json:"papers,omitempty"`        // Optional: Direct paper data
		InputFile    string         `json:"input_file,omitempty"`    // Optional: Input file path
		CriteriaFile string         `json:"criteria_file,omitempty"` // Optional: Criteria file path
		Criteria     string         `json:"criteria,omitempty"`      // Optional: Direct criteria text
		ApiKey       string         `json:"api_key"`                 // Required: API key
		Model        string         `json:"model,omitempty"`         // Optional: Model name
	}

	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Invalid request body", http.StatusBadRequest)
		return
	}

	// Validate required fields
	if req.CriteriaFile == "" && req.Criteria == "" {
		http.Error(w, "either criteria_file or criteria must be provided", http.StatusBadRequest)
		return
	}
	if req.ApiKey == "" {
		http.Error(w, "api_key is required", http.StatusBadRequest)
		return
	}

	// Create processor configuration
	config := paperprocessor.Config{
		APIEndpoint:  s.apiEndpoint,
		APIKey:       req.ApiKey,
		Model:        req.Model,
		RequestDelay: 2 * time.Second,
	}

	var inputJSON string

	// Handle direct paper data
	if len(req.Papers) > 0 {
		// Create temporary file for paper data
		tempFile, err := os.CreateTemp("", "papers-*.json")
		if err != nil {
			http.Error(w, fmt.Sprintf("Failed to create temp file: %v", err), http.StatusInternalServerError)
			return
		}
		defer os.Remove(tempFile.Name()) // Clean up temp file

		// Write papers to temp file
		if err := json.NewEncoder(tempFile).Encode(req.Papers); err != nil {
			http.Error(w, fmt.Sprintf("Failed to write papers: %v", err), http.StatusInternalServerError)
			return
		}
		tempFile.Close()
		inputJSON = tempFile.Name()
	} else if req.InputFile != "" {
		inputJSON = req.InputFile
	} else {
		http.Error(w, "either papers or input_file must be provided", http.StatusBadRequest)
		return
	}

	// Generate output filenames
	timestamp := time.Now().Format("20060102150405")
	outputJSON := fmt.Sprintf("processed-%s.json", timestamp)
	outputMD := fmt.Sprintf("processed-%s.md", timestamp)

	// Handle criteria
	var criteriaFile string
	if req.Criteria != "" {
		// Create temporary file for criteria
		tempFile, err := os.CreateTemp("", "criteria-*.md")
		if err != nil {
			http.Error(w, fmt.Sprintf("Failed to create temp criteria file: %v", err), http.StatusInternalServerError)
			return
		}
		defer os.Remove(tempFile.Name()) // Clean up temp file

		// Write criteria to temp file
		if _, err := tempFile.WriteString(req.Criteria); err != nil {
			http.Error(w, fmt.Sprintf("Failed to write criteria: %v", err), http.StatusInternalServerError)
			return
		}
		tempFile.Close()
		criteriaFile = tempFile.Name()
	} else {
		criteriaFile = req.CriteriaFile
	}

	// Process the papers
	if err := paperprocessor.ProcessFile(
		inputJSON,
		outputJSON,
		criteriaFile,
		config,
	); err != nil {
		http.Error(w, fmt.Sprintf("Processing failed: %v", err), http.StatusInternalServerError)
		return
	}

	// Format to markdown
	if err := paperformatter.FormatPapers(outputJSON, outputMD); err != nil {
		http.Error(w, fmt.Sprintf("Formatting failed: %v", err), http.StatusInternalServerError)
		return
	}

	// Generate job ID and create job
	jobID := fmt.Sprintf("job-%s", timestamp)
	job := &ProcessingJob{
		ID:        jobID,
		Status:    "pending",
		StartTime: time.Now(),
		JSONPath:  outputJSON,
		MDPath:    outputMD,
	}

	// Store job
	s.jobsMutex.Lock()
	s.jobs[jobID] = job
	s.jobsMutex.Unlock()

	// Start processing in background
	go func() {
		// Process the papers
		if err := paperprocessor.ProcessFile(
			inputJSON,
			outputJSON,
			criteriaFile,
			config,
		); err != nil {
			s.jobsMutex.Lock()
			job.Status = "failed"
			job.Error = fmt.Sprintf("Processing failed: %v", err)
			s.jobsMutex.Unlock()
			return
		}

		// Format to markdown
		if err := paperformatter.FormatPapers(outputJSON, outputMD); err != nil {
			s.jobsMutex.Lock()
			job.Status = "failed"
			job.Error = fmt.Sprintf("Formatting failed: %v", err)
			s.jobsMutex.Unlock()
			return
		}

		// Read markdown content
		mdContent, err := os.ReadFile(outputMD)
		if err != nil {
			s.jobsMutex.Lock()
			job.Status = "failed"
			job.Error = fmt.Sprintf("Failed to read markdown: %v", err)
			s.jobsMutex.Unlock()
			return
		}

		// Convert Windows line endings to Unix
		mdString := strings.ReplaceAll(string(mdContent), "\r\n", "\n")
		// Ensure file ends with newline
		if !strings.HasSuffix(mdString, "\n") {
			mdString += "\n"
		}

		// Update job with success
		s.jobsMutex.Lock()
		job.Status = "completed"
		job.MarkdownText = mdString
		s.jobsMutex.Unlock()
	}()

	// Return job ID immediately
	json.NewEncoder(w).Encode(struct {
		JobID string `json:"job_id"`
	}{
		JobID: jobID,
	})
}

func (s *Server) handleJobStatus(w http.ResponseWriter, r *http.Request) {
	jobID := chi.URLParam(r, "jobID")

	s.jobsMutex.RLock()
	job, exists := s.jobs[jobID]
	s.jobsMutex.RUnlock()

	if !exists {
		http.Error(w, "Job not found", http.StatusNotFound)
		return
	}

	response := struct {
		ID           string    `json:"id"`
		Status       string    `json:"status"`
		StartTime    time.Time `json:"start_time"`
		Error        string    `json:"error,omitempty"`
		MarkdownText string    `json:"markdown_text,omitempty"`
	}{
		ID:        job.ID,
		Status:    job.Status,
		StartTime: job.StartTime,
		Error:     job.Error,
	}

	// Only include markdown text if job is completed
	if job.Status == "completed" {
		response.MarkdownText = job.MarkdownText
	}

	json.NewEncoder(w).Encode(response)
}

func (s *Server) handleSearchAndProcess(w http.ResponseWriter, r *http.Request) {
	var req struct {
		StartDate    string `json:"start_date"`
		EndDate      string `json:"end_date"`
		Query        string `json:"query"`
		MaxResults   int    `json:"max_results"`
		CriteriaFile string `json:"criteria_file,omitempty"`
		Criteria     string `json:"criteria,omitempty"`
		ApiKey       string `json:"api_key"`
		Model        string `json:"model,omitempty"`
	}

	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Invalid request body", http.StatusBadRequest)
		return
	}

	// Validate dates
	if !IsValidDate(req.StartDate) || !IsValidDate(req.EndDate) {
		http.Error(w, "Invalid date format", http.StatusBadRequest)
		return
	}

	// Fetch papers
	papers, err := arxiva.FetchPapers(req.StartDate, req.EndDate, req.Query, req.MaxResults)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Save papers to temporary JSON file
	baseFilename := fmt.Sprintf("%s-%s-%s", req.StartDate, req.EndDate, SanitizeFilename(req.Query))
	inputJSON := baseFilename + ".json"
	if err := arxiva.SaveToFile(papers, req.StartDate, req.EndDate, req.Query); err != nil {
		http.Error(w, fmt.Sprintf("Failed to save papers: %v", err), http.StatusInternalServerError)
		return
	}

	// Create processor configuration
	config := paperprocessor.Config{
		APIEndpoint:  s.apiEndpoint,
		APIKey:       req.ApiKey,
		Model:        req.Model,
		RequestDelay: 2 * time.Second,
	}

	// Handle criteria
	var criteriaFile string
	var tempCriteriaFile string // Track temporary file for cleanup

	if req.Criteria != "" {
		// Create temporary file for criteria
		tempFile, err := os.CreateTemp("", "criteria-*.md")
		if err != nil {
			http.Error(w, fmt.Sprintf("Failed to create temp criteria file: %v", err), http.StatusInternalServerError)
			return
		}
		tempCriteriaFile = tempFile.Name() // Save for cleanup after processing

		// Write criteria to temp file
		if _, err := tempFile.WriteString(req.Criteria); err != nil {
			os.Remove(tempCriteriaFile) // Clean up on error
			http.Error(w, fmt.Sprintf("Failed to write criteria: %v", err), http.StatusInternalServerError)
			return
		}
		tempFile.Close()
		criteriaFile = tempCriteriaFile
	} else if req.CriteriaFile != "" {
		criteriaFile = req.CriteriaFile
	} else {
		http.Error(w, "either criteria_file or criteria must be provided", http.StatusBadRequest)
		return
	}

	// Process the papers
	outputJSON := baseFilename + "-processed.json"
	if err := paperprocessor.ProcessFile(
		inputJSON,
		outputJSON,
		criteriaFile,
		config,
	); err != nil {
		if tempCriteriaFile != "" {
			os.Remove(tempCriteriaFile) // Clean up temp file on error
		}
		http.Error(w, fmt.Sprintf("Processing failed: %v", err), http.StatusInternalServerError)
		return
	}

	// Format to markdown
	outputMD := baseFilename + "-processed.md"
	if err := paperformatter.FormatPapers(outputJSON, outputMD); err != nil {
		http.Error(w, fmt.Sprintf("Formatting failed: %v", err), http.StatusInternalServerError)
		return
	}

	// Generate job ID and create job
	jobID := fmt.Sprintf("job-%s", baseFilename)
	job := &ProcessingJob{
		ID:        jobID,
		Status:    "pending",
		StartTime: time.Now(),
		JSONPath:  outputJSON,
		MDPath:    outputMD,
	}

	// Store job
	s.jobsMutex.Lock()
	s.jobs[jobID] = job
	s.jobsMutex.Unlock()

	// Start processing in background
	go func() {
		defer func() {
			if tempCriteriaFile != "" {
				os.Remove(tempCriteriaFile) // Clean up temp file after processing
			}
		}()

		// Process the papers
		if err := paperprocessor.ProcessFile(
			inputJSON,
			outputJSON,
			criteriaFile,
			config,
		); err != nil {
			s.jobsMutex.Lock()
			job.Status = "failed"
			job.Error = fmt.Sprintf("Processing failed: %v", err)
			s.jobsMutex.Unlock()
			return
		}

		// Format to markdown
		if err := paperformatter.FormatPapers(outputJSON, outputMD); err != nil {
			s.jobsMutex.Lock()
			job.Status = "failed"
			job.Error = fmt.Sprintf("Formatting failed: %v", err)
			s.jobsMutex.Unlock()
			return
		}

		// Read markdown content
		mdContent, err := os.ReadFile(outputMD)
		if err != nil {
			s.jobsMutex.Lock()
			job.Status = "failed"
			job.Error = fmt.Sprintf("Failed to read markdown: %v", err)
			s.jobsMutex.Unlock()
			return
		}

		// Convert Windows line endings to Unix
		mdString := strings.ReplaceAll(string(mdContent), "\r\n", "\n")
		// Ensure file ends with newline
		if !strings.HasSuffix(mdString, "\n") {
			mdString += "\n"
		}

		// Update job with success
		s.jobsMutex.Lock()
		job.Status = "completed"
		job.MarkdownText = mdString
		s.jobsMutex.Unlock()
	}()

	// Return job ID immediately
	json.NewEncoder(w).Encode(struct {
		JobID string `json:"job_id"`
	}{
		JobID: jobID,
	})
}