//go:build llm_script

package main

import (
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strings"
	"time"
)

type deepseekPricingStructureSignature struct {
	ByteSize        int             `json:"byte_size"`
	SHA256          string          `json:"sha256"`
	StructureSHA256 string          `json:"structure_sha256"`
	Title           string          `json:"title"`
	MetaDescription string          `json:"meta_description"`
	CommitID        string          `json:"commit_id"`
	CanonicalURL    string          `json:"canonical_url"`
	Contains        map[string]bool `json:"contains"`
	GeneratedAt     string          `json:"generated_at,omitempty"`
	SourceURL       string          `json:"source_url,omitempty"`
	SnapshotPath    string          `json:"snapshot_path,omitempty"`
}

var deepseekPricingContainsNeedles = map[string]string{
	"deepseek":  "deepseek",
	"platform":  "platform",
	"pricing":   "pricing",
	"api_docs":  "api",
	"developer": "developer resources",
}

var deepseekPricingTitleRe = regexp.MustCompile(`(?is)<title[^>]*>(.*?)</title>`)
var deepseekPricingMetaDescRe = regexp.MustCompile(`(?is)<meta[^>]+name=["']description["'][^>]+content=["']([^"']+)["']`)
var deepseekPricingCommitRe = regexp.MustCompile(`(?is)<meta[^>]+name=["']commit-id["'][^>]+content=["']([^"']+)["']`)
var deepseekPricingCanonicalRe = regexp.MustCompile(`(?is)<meta[^>]+property=["']og:url["'][^>]+content=["']([^"']+)["']`)
var deepseekPricingHTMLTagRe = regexp.MustCompile(`(?s)<[^>]+>`)

func buildDeepSeekPricingStructureSignature(raw string) deepseekPricingStructureSignature {
	title := firstDeepSeekPricingHTMLMatch(deepseekPricingTitleRe, raw)
	meta := firstDeepSeekPricingHTMLMatch(deepseekPricingMetaDescRe, raw)
	commitID := firstDeepSeekPricingHTMLMatch(deepseekPricingCommitRe, raw)
	canonicalURL := firstDeepSeekPricingHTMLMatch(deepseekPricingCanonicalRe, raw)
	contains := make(map[string]bool, len(deepseekPricingContainsNeedles))
	lower := strings.ToLower(raw)
	for key, needle := range deepseekPricingContainsNeedles {
		contains[key] = strings.Contains(lower, strings.ToLower(needle))
	}
	signature := deepseekPricingStructureSignature{
		ByteSize:        len([]byte(raw)),
		SHA256:          deepseekPricingSHA256Hex(raw),
		Title:           title,
		MetaDescription: meta,
		CommitID:        commitID,
		CanonicalURL:    canonicalURL,
		Contains:        contains,
	}
	signature.StructureSHA256 = deepseekPricingSHA256Hex(deepseekPricingStructureDigestPayload(signature))
	return signature
}

func writeDeepSeekPricingSnapshotArtifacts(raw string, sourceURL string, snapshotPath string, signaturePath string, now time.Time) (deepseekPricingStructureSignature, error) {
	if strings.TrimSpace(snapshotPath) == "" {
		return deepseekPricingStructureSignature{}, fmt.Errorf("snapshot path is required")
	}
	if strings.TrimSpace(signaturePath) == "" {
		return deepseekPricingStructureSignature{}, fmt.Errorf("signature path is required")
	}
	if err := os.MkdirAll(filepath.Dir(snapshotPath), 0o755); err != nil {
		return deepseekPricingStructureSignature{}, fmt.Errorf("mkdir snapshot dir: %w", err)
	}
	if err := os.MkdirAll(filepath.Dir(signaturePath), 0o755); err != nil {
		return deepseekPricingStructureSignature{}, fmt.Errorf("mkdir signature dir: %w", err)
	}
	if err := os.WriteFile(snapshotPath, []byte(raw), 0o644); err != nil {
		return deepseekPricingStructureSignature{}, fmt.Errorf("write snapshot: %w", err)
	}
	signature := buildDeepSeekPricingStructureSignature(raw)
	signature.GeneratedAt = now.Format(time.RFC3339)
	signature.SourceURL = sourceURL
	signature.SnapshotPath = snapshotPath
	payload, err := json.MarshalIndent(signature, "", "  ")
	if err != nil {
		return deepseekPricingStructureSignature{}, fmt.Errorf("marshal signature: %w", err)
	}
	if err := os.WriteFile(signaturePath, payload, 0o644); err != nil {
		return deepseekPricingStructureSignature{}, fmt.Errorf("write signature: %w", err)
	}
	return signature, nil
}

func resolveDeepSeekPricingSnapshotPaths(snapshotPath string, signaturePath string, snapshotDir string, baseName string, now time.Time) (string, string) {
	if strings.TrimSpace(snapshotDir) == "" {
		snapshotDir = filepath.Join("logs", baseName+"-snapshots")
	}
	if strings.TrimSpace(snapshotPath) == "" {
		base := filepath.Join(snapshotDir, fmt.Sprintf("%s-%s", baseName, now.Format("20060102-150405")))
		snapshotPath = base + ".html"
		if strings.TrimSpace(signaturePath) == "" {
			signaturePath = base + ".signature.json"
		}
	}
	if strings.TrimSpace(signaturePath) == "" {
		signaturePath = strings.TrimSuffix(snapshotPath, filepath.Ext(snapshotPath)) + ".signature.json"
	}
	return snapshotPath, signaturePath
}

func readDeepSeekPricingStructureSignature(path string) (deepseekPricingStructureSignature, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return deepseekPricingStructureSignature{}, err
	}
	var signature deepseekPricingStructureSignature
	if err := json.Unmarshal(data, &signature); err != nil {
		return deepseekPricingStructureSignature{}, fmt.Errorf("unmarshal signature %s: %w", path, err)
	}
	return signature, nil
}

func hasDeepSeekPricingStructureSignature(signature deepseekPricingStructureSignature) bool {
	return signature.ByteSize > 0 ||
		strings.TrimSpace(signature.StructureSHA256) != "" ||
		strings.TrimSpace(signature.SHA256) != "" ||
		strings.TrimSpace(signature.Title) != "" ||
		strings.TrimSpace(signature.CommitID) != "" ||
		len(signature.Contains) > 0
}

func deepseekPricingStructureDigestPayload(signature deepseekPricingStructureSignature) string {
	type containsEntry struct {
		Name  string `json:"name"`
		Value bool   `json:"value"`
	}
	keys := make([]string, 0, len(signature.Contains))
	for key := range signature.Contains {
		keys = append(keys, key)
	}
	sort.Strings(keys)
	entries := make([]containsEntry, 0, len(keys))
	for _, key := range keys {
		entries = append(entries, containsEntry{Name: key, Value: signature.Contains[key]})
	}
	payload := struct {
		Title           string          `json:"title"`
		MetaDescription string          `json:"meta_description"`
		CommitID        string          `json:"commit_id"`
		CanonicalURL    string          `json:"canonical_url"`
		Contains        []containsEntry `json:"contains"`
	}{
		Title:           signature.Title,
		MetaDescription: signature.MetaDescription,
		CommitID:        signature.CommitID,
		CanonicalURL:    signature.CanonicalURL,
		Contains:        entries,
	}
	bytes, _ := json.Marshal(payload)
	return string(bytes)
}

func deepseekPricingSHA256Hex(raw string) string {
	sum := sha256.Sum256([]byte(raw))
	return hex.EncodeToString(sum[:])
}

func firstDeepSeekPricingHTMLMatch(re *regexp.Regexp, raw string) string {
	match := re.FindStringSubmatch(raw)
	if len(match) < 2 {
		return ""
	}
	text := deepseekPricingHTMLTagRe.ReplaceAllString(match[1], " ")
	text = strings.ReplaceAll(text, "&amp;", "&")
	text = strings.ReplaceAll(text, "&nbsp;", " ")
	text = strings.Join(strings.Fields(text), " ")
	return strings.TrimSpace(text)
}