package worker

import (
	"context"
	"crypto/rand"
	"database/sql"
	"encoding/binary"
	"encoding/hex"
	"fmt"
	"log"
	"math"
	"time"

	"dealroom/internal/extract"
	"dealroom/internal/fireworks"
)

const matchThreshold = 0.72

type ExtractionJob struct {
	ResponseID string
	FilePath   string // absolute path to uploaded file (or "" for statements)
	DealID     string
}

type Extractor struct {
	db   *sql.DB
	fw   *fireworks.Client
	jobs chan ExtractionJob
}

func NewExtractor(db *sql.DB, fw *fireworks.Client) *Extractor {
	return &Extractor{
		db:   db,
		fw:   fw,
		jobs: make(chan ExtractionJob, 100),
	}
}

func (e *Extractor) Start() {
	for i := 0; i < 2; i++ {
		go e.worker(i)
	}
	log.Println("Extraction worker started (2 goroutines)")
}

func (e *Extractor) Enqueue(job ExtractionJob) {
	e.jobs <- job
}

func (e *Extractor) worker(id int) {
	for job := range e.jobs {
		e.process(id, job)
	}
}

func (e *Extractor) process(workerID int, job ExtractionJob) {
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Minute)
	defer cancel()

	log.Printf("[extractor-%d] Processing response %s (deal=%s, file=%s)", workerID, job.ResponseID, job.DealID, job.FilePath)

	// Set status to processing
	e.db.Exec("UPDATE responses SET extraction_status = 'processing', updated_at = datetime('now') WHERE id = ?", job.ResponseID)

	var body string

	if job.FilePath != "" {
		// Document: extract text from file
		md, err := e.extractFile(ctx, job)
		if err != nil {
			log.Printf("[extractor-%d] Extraction failed for %s: %v", workerID, job.ResponseID, err)
			e.db.Exec("UPDATE responses SET extraction_status = 'failed', updated_at = datetime('now') WHERE id = ?", job.ResponseID)
			return
		}
		body = md
		// Update response body and status
		e.db.Exec("UPDATE responses SET body = ?, extraction_status = 'done', updated_at = datetime('now') WHERE id = ?", body, job.ResponseID)
	} else {
		// Statement: body is already set, just mark done
		e.db.Exec("UPDATE responses SET extraction_status = 'done', updated_at = datetime('now') WHERE id = ?", job.ResponseID)
		// Load existing body
		e.db.QueryRow("SELECT body FROM responses WHERE id = ?", job.ResponseID).Scan(&body)
	}

	if body == "" {
		log.Printf("[extractor-%d] Empty body for response %s, skipping chunk+match", workerID, job.ResponseID)
		return
	}

	// Chunk
	chunks := extract.ChunkMarkdown(body)
	if len(chunks) == 0 {
		log.Printf("[extractor-%d] No chunks produced for response %s", workerID, job.ResponseID)
		return
	}

	// Embed chunks
	chunkVectors, err := e.fw.EmbedText(ctx, chunks)
	if err != nil {
		log.Printf("[extractor-%d] Embedding failed for %s: %v", workerID, job.ResponseID, err)
		e.db.Exec("UPDATE responses SET extraction_status = 'failed', updated_at = datetime('now') WHERE id = ?", job.ResponseID)
		return
	}

	// Store chunks
	chunkIDs := make([]string, len(chunks))
	for i, chunk := range chunks {
		chunkID := generateID("chunk")
		chunkIDs[i] = chunkID
		vecBytes := float32sToBytes(chunkVectors[i])
		e.db.Exec("INSERT INTO response_chunks (id, response_id, chunk_index, text, vector) VALUES (?, ?, ?, ?, ?)",
			chunkID, job.ResponseID, i, chunk, vecBytes)
	}

	// Match against open requests in this deal
	linkCount := e.matchRequests(ctx, job.DealID, job.ResponseID, chunkIDs, chunkVectors)

	log.Printf("[extractor-%d] Response %s: %d chunks, %d request links auto-created", workerID, job.ResponseID, len(chunks), linkCount)
}

func (e *Extractor) extractFile(ctx context.Context, job ExtractionJob) (string, error) {
	if extract.IsXLSX(job.FilePath) {
		// XLSX: extract text dump, send as text to LLM
		text, err := extract.XLSXToText(job.FilePath)
		if err != nil {
			return "", fmt.Errorf("xlsx extract: %w", err)
		}
		md, err := e.fw.ExtractTextToMarkdown(ctx, text, job.FilePath)
		if err != nil {
			return "", fmt.Errorf("xlsx to markdown: %w", err)
		}
		return md, nil
	}

	// PDF or image
	images, err := extract.FileToImages(job.FilePath)
	if err != nil {
		return "", fmt.Errorf("file to images: %w", err)
	}
	if len(images) == 0 {
		return "", fmt.Errorf("no images extracted from file")
	}

	md, err := e.fw.ExtractToMarkdown(ctx, images, job.FilePath)
	if err != nil {
		return "", fmt.Errorf("vision extraction: %w", err)
	}
	return md, nil
}

func (e *Extractor) matchRequests(ctx context.Context, dealID, responseID string, chunkIDs []string, chunkVectors [][]float32) int {
	// Load all requests for this deal
	rows, err := e.db.Query("SELECT id, description FROM diligence_requests WHERE deal_id = ?", dealID)
	if err != nil {
		log.Printf("[extractor] Failed to load requests for deal %s: %v", dealID, err)
		return 0
	}
	defer rows.Close()

	type reqInfo struct {
		id, desc string
	}
	var reqs []reqInfo
	for rows.Next() {
		var r reqInfo
		rows.Scan(&r.id, &r.desc)
		reqs = append(reqs, r)
	}

	if len(reqs) == 0 {
		return 0
	}

	// Embed request descriptions
	descs := make([]string, len(reqs))
	for i, r := range reqs {
		descs[i] = r.desc
	}
	reqVectors, err := e.fw.EmbedText(ctx, descs)
	if err != nil {
		log.Printf("[extractor] Failed to embed request descriptions: %v", err)
		return 0
	}

	// Match each (chunk, request) pair
	linkCount := 0
	for ci, chunkVec := range chunkVectors {
		for ri, reqVec := range reqVectors {
			sim := fireworks.CosineSimilarity(chunkVec, reqVec)
			if sim >= matchThreshold {
				_, err := e.db.Exec(
					"INSERT OR IGNORE INTO request_links (request_id, response_id, chunk_id, confidence, auto_linked, confirmed) VALUES (?, ?, ?, ?, 1, 0)",
					reqs[ri].id, responseID, chunkIDs[ci], sim)
				if err == nil {
					linkCount++
				}
			}
		}
	}

	return linkCount
}

func float32sToBytes(fs []float32) []byte {
	buf := make([]byte, len(fs)*4)
	for i, f := range fs {
		binary.LittleEndian.PutUint32(buf[i*4:], math.Float32bits(f))
	}
	return buf
}

func generateID(prefix string) string {
	b := make([]byte, 8)
	rand.Read(b)
	return prefix + "-" + hex.EncodeToString(b)
}