package app

import (
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"net/http"
	"net/url"
	"strings"
	"time"

	"github.com/b1tsblog/ai-disclosure-standard/internal/declaration"
	"github.com/b1tsblog/ai-disclosure-standard/internal/i18n"
)

type bulkRequest struct {
	Items []bulkItem `json:"items"`
}

type bulkItem struct {
	ID         string            `json:"id,omitempty"`
	Parameters map[string]string `json:"parameters"`
}

type bulkResult struct {
	ID             string                           `json:"id,omitempty"`
	Valid          bool                             `json:"valid"`
	Declaration    *declaration.Declaration         `json:"declaration,omitempty"`
	Assessment     *declaration.Article50Assessment `json:"article50Assessment,omitempty"`
	DeclarationURL string                           `json:"declarationUrl,omitempty"`
	ManifestURL    string                           `json:"manifestUrl,omitempty"`
	BadgeURL       string                           `json:"badgeUrl,omitempty"`
	Error          *bulkError                       `json:"error,omitempty"`
}

type bulkError struct {
	Code   string `json:"code"`
	Detail string `json:"detail"`
}

type declarationBundle struct {
	Product           string                          `json:"product"`
	ProductVersion    string                          `json:"productVersion"`
	GeneratedAt       string                          `json:"generatedAt"`
	Declaration       declaration.Declaration         `json:"declaration"`
	DeclarationDigest string                          `json:"declarationDigest"`
	Assessment        declaration.Article50Assessment `json:"article50Assessment"`
	DeclarationURL    string                          `json:"declarationUrl"`
	ManifestURL       string                          `json:"manifestUrl"`
	BadgeURL          string                          `json:"badgeUrl"`
}

func (s *Server) handleBulkDeclarations(w http.ResponseWriter, r *http.Request) {
	s.metrics.bulkRequests.Add(1)
	if !s.bulkAuthorized(r) {
		s.metrics.bulkFailures.Add(1)
		w.Header().Set("WWW-Authenticate", `Bearer realm="bulk-api"`)
		s.problem(w, http.StatusUnauthorized, "bulk_authentication_required", "A valid bulk API key is required.")
		return
	}
	if !s.licenses.Has(FeatureBulkAPI) {
		s.metrics.bulkFailures.Add(1)
		s.problem(w, http.StatusForbidden, "licensed_feature_required", "The bulk API requires the licensed capability bulk_api.")
		return
	}
	limit := s.cfg.BulkMaxItems
	if licensedLimit, ok := s.licenses.Limit("bulk_items"); ok && licensedLimit > 0 && int64(limit) > licensedLimit {
		limit = int(licensedLimit)
	}
	body := http.MaxBytesReader(w, r.Body, s.cfg.BulkMaxBodyBytes)
	defer body.Close()
	dec := json.NewDecoder(body)
	dec.DisallowUnknownFields()
	var request bulkRequest
	if err := dec.Decode(&request); err != nil {
		s.metrics.bulkFailures.Add(1)
		s.problem(w, http.StatusBadRequest, "invalid_json", err.Error())
		return
	}
	if err := ensureEOF(dec); err != nil {
		s.metrics.bulkFailures.Add(1)
		s.problem(w, http.StatusBadRequest, "invalid_json", err.Error())
		return
	}
	if len(request.Items) == 0 {
		s.metrics.bulkFailures.Add(1)
		s.problem(w, http.StatusBadRequest, "empty_bulk_request", "At least one item is required.")
		return
	}
	if len(request.Items) > limit {
		s.metrics.bulkFailures.Add(1)
		s.problem(w, http.StatusRequestEntityTooLarge, "bulk_limit_exceeded", "The request exceeds the configured or licensed bulk item limit.")
		return
	}
	s.metrics.bulkItems.Add(uint64(len(request.Items)))
	results := make([]bulkResult, 0, len(request.Items))
	for _, item := range request.Items {
		q := url.Values{}
		for key, value := range item.Parameters {
			q.Set(key, value)
		}
		if q.Get("lang") == "" {
			q.Set("lang", s.cfg.DefaultLanguage)
		}
		d, err := s.declarationFromQuery(q)
		if err != nil {
			results = append(results, bulkResult{ID: strings.TrimSpace(item.ID), Valid: false, Error: &bulkError{Code: "invalid_declaration", Detail: err.Error()}})
			continue
		}
		assessment := declaration.AssessArticle50(d)
		declarationURL, manifestURL, badgeURL := s.generatedURLs(q)
		results = append(results, bulkResult{
			ID: strings.TrimSpace(item.ID), Valid: true, Declaration: &d, Assessment: &assessment,
			DeclarationURL: declarationURL, ManifestURL: manifestURL, BadgeURL: badgeURL,
		})
	}
	s.writeJSON(w, http.StatusOK, map[string]any{
		"product": ProductID, "productVersion": ProductVersion, "count": len(results), "items": results,
	})
}

func (s *Server) handleArticle50Assessment(w http.ResponseWriter, r *http.Request) {
	q := cloneValues(r.URL.Query())
	q.Set("lang", s.languageFromValues(r, q))
	d, err := s.declarationFromQuery(q)
	if err != nil {
		s.declarationError(w, err)
		return
	}
	locale := i18n.Get(d.Language)
	assessment := declaration.AssessArticle50(d)
	view := article50AssessmentView(assessment, locale)
	s.writeJSON(w, http.StatusOK, map[string]any{
		"assessment": assessment,
		"title":      view.Title,
		"summary":    view.Summary,
		"findings":   view.Details,
		"warnings":   view.Warnings,
		"disclaimer": locale.Text["assessment_disclaimer"],
	})
}

func (s *Server) handleDeclarationBundle(w http.ResponseWriter, r *http.Request) {
	if !s.licenses.Has(FeatureExportBundle) {
		s.problem(w, http.StatusForbidden, "licensed_feature_required", "Declaration bundles require the licensed capability export_bundle.")
		return
	}
	q := cloneValues(r.URL.Query())
	q.Set("lang", s.languageFromValues(r, q))
	d, err := s.declarationFromQuery(q)
	if err != nil {
		s.declarationError(w, err)
		return
	}
	declarationURL, manifestURL, badgeURL := s.generatedURLs(q)
	bundle := declarationBundle{
		Product: ProductID, ProductVersion: ProductVersion, GeneratedAt: time.Now().UTC().Format(time.RFC3339),
		Declaration: d, DeclarationDigest: declarationDigest(d), Assessment: declaration.AssessArticle50(d), DeclarationURL: declarationURL, ManifestURL: manifestURL, BadgeURL: badgeURL,
	}
	w.Header().Set("Cache-Control", "no-store")
	s.writeJSON(w, http.StatusOK, bundle)
}

func (s *Server) generatedURLs(q url.Values) (string, string, string) {
	encoded := q.Encode()
	base := s.cfg.OutputBaseURL
	if base == "" {
		base = s.cfg.BaseURL
	}
	declarationURL := base + "/declaration?" + encoded
	manifestURL := base + "/v1/declaration.json?" + encoded
	badgeQ := cloneValues(q)
	badgeQ.Set("link", declarationURL)
	badgeURL := base + "/v1/badge.svg?" + badgeQ.Encode()
	return declarationURL, manifestURL, badgeURL
}

func declarationDigest(d declaration.Declaration) string {
	encoded, err := json.Marshal(d)
	if err != nil {
		return ""
	}
	digest := sha256.Sum256(encoded)
	return "sha256:" + hex.EncodeToString(digest[:])
}