package main

import (
	"errors"
	"net/http"
	"strings"

	"github.com/go-chi/chi/v5"
)

func (a *app) scormLearnerMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		claims, _ := r.Context().Value(userClaimsKey).(*accessClaims)
		if claims == nil {
			writeError(w, http.StatusUnauthorized, "no authenticated user")
			return
		}
		if !hasRole(claims, "learner") && !hasRole(claims, "admin") && !hasRole(claims, "instructor") {
			writeError(w, http.StatusForbidden, "insufficient role for learner scorm access")
			return
		}
		next.ServeHTTP(w, r)
	})
}

func (a *app) listLearnerScormCourses(w http.ResponseWriter, r *http.Request) {
	if a.db == nil {
		writeError(w, http.StatusServiceUnavailable, "database not configured")
		return
	}

	userID, ok := a.learnerSubjectFromContext(r)
	if !ok {
		writeError(w, http.StatusUnauthorized, "missing learner subject")
		return
	}

	enrollments, err := a.list("enrollments", Doc{"userId": userID}, Sort{{Key: "updatedAt", Value: -1}, {Key: "createdAt", Value: -1}})
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to list learner enrollments")
		return
	}

	courseIDs := make(map[string]struct{})
	filteredEnrollments := make([]Doc, 0, len(enrollments))
	for _, enrollment := range enrollments {
		courseID, _ := asString(enrollment["courseId"])
		if courseID == "" {
			continue
		}
		courseType, _ := asString(enrollment["courseType"])
		if courseType != "" && !strings.EqualFold(courseType, "scorm") {
			continue
		}
		filteredEnrollments = append(filteredEnrollments, enrollment)
		courseIDs[courseID] = struct{}{}
	}

	if len(courseIDs) == 0 {
		writeJSON(w, http.StatusOK, []Doc{})
		return
	}

	courses, err := a.list("scorm_courses", Doc{"id": Doc{"$in": mapKeys(courseIDs)}}, Sort{{Key: "updatedAt", Value: -1}})
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to load scorm courses")
		return
	}
	courseByID := indexByID(courses)

	exports, err := a.list("scorm_exports", Doc{"courseId": Doc{"$in": mapKeys(courseIDs)}}, Sort{{Key: "createdAt", Value: -1}})
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to load scorm exports")
		return
	}
	exportsByCourse := make(map[string][]Doc)
	for _, exportDoc := range exports {
		courseID, _ := asString(exportDoc["courseId"])
		if courseID == "" {
			continue
		}
		exportsByCourse[courseID] = append(exportsByCourse[courseID], exportDoc)
	}

	items := make([]Doc, 0, len(filteredEnrollments))
	seenCourse := make(map[string]struct{})
	for _, enrollment := range filteredEnrollments {
		courseID, _ := asString(enrollment["courseId"])
		if courseID == "" {
			continue
		}
		if _, exists := seenCourse[courseID]; exists {
			continue
		}
		course := courseByID[courseID]
		if course == nil {
			continue
		}

		hasEntitlement, entitlementReason, entitlementMessage, err := a.learnerEntitlementDecision(r, userID, resolveEntitlementKey(course, nil))
		if err != nil {
			writeError(w, http.StatusInternalServerError, "failed to evaluate learner entitlement")
			return
		}

		seenCourse[courseID] = struct{}{}
		items = append(items, Doc{
			"course":      course,
			"enrollment":  enrollment,
			"launchState": evaluateLearnerScormLaunch(course, enrollment, exportsByCourse[courseID], hasEntitlement, entitlementReason, entitlementMessage),
		})
	}

	writeJSON(w, http.StatusOK, items)
}

func (a *app) getLearnerScormLaunch(w http.ResponseWriter, r *http.Request) {
	if a.db == nil {
		writeError(w, http.StatusServiceUnavailable, "database not configured")
		return
	}

	userID, ok := a.learnerSubjectFromContext(r)
	if !ok {
		writeError(w, http.StatusUnauthorized, "missing learner subject")
		return
	}

	courseID := strings.TrimSpace(chi.URLParam(r, "id"))
	if courseID == "" {
		writeError(w, http.StatusBadRequest, "scorm course id is required")
		return
	}

	course, err := a.getByID("scorm_courses", courseID)
	if err != nil {
		if errors.Is(err, ErrNotFound) {
			writeError(w, http.StatusNotFound, "scorm course not found")
			return
		}
		writeError(w, http.StatusInternalServerError, "failed to load scorm course")
		return
	}

	enrollments, err := a.list("enrollments", Doc{"userId": userID, "courseId": courseID}, Sort{{Key: "updatedAt", Value: -1}, {Key: "createdAt", Value: -1}})
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to load learner enrollment")
		return
	}
	enrollment := firstDocument(enrollments)

	exports, err := a.list("scorm_exports", Doc{"courseId": courseID}, Sort{{Key: "createdAt", Value: -1}})
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to load scorm exports")
		return
	}

	hasEntitlement, entitlementReason, entitlementMessage, err := a.learnerEntitlementDecision(r, userID, resolveEntitlementKey(course, nil))
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to evaluate learner entitlement")
		return
	}

	launchState := evaluateLearnerScormLaunch(course, enrollment, exports, hasEntitlement, entitlementReason, entitlementMessage)
	writeJSON(w, http.StatusOK, Doc{
		"course":      course,
		"enrollment":  enrollment,
		"launchState": launchState,
	})
}

func evaluateLearnerScormLaunch(course, enrollment Doc, exports []Doc, entitlementAllowed bool, entitlementReason, entitlementMessage string) Doc {
	if course == nil {
		return Doc{
			"allowed":      false,
			"state":        "locked",
			"reason":       "missing_course",
			"message":      "SCORM course was not found.",
			"progressNote": "Progress sync is unavailable because this SCORM course could not be loaded.",
		}
	}

	if enrollment == nil {
		return Doc{
			"allowed":      false,
			"state":        "locked",
			"reason":       "missing_enrollment",
			"message":      "You are not currently enrolled in this SCORM course.",
			"progressNote": "Resume is unavailable until enrollment is active.",
		}
	}

	status, _ := asString(enrollment["status"])
	if !isLearnerScormEnrollmentActive(status) {
		return Doc{
			"allowed":      false,
			"state":        "locked",
			"reason":       "inactive_enrollment",
			"message":      "Your enrollment is not active for SCORM launch.",
			"progressNote": "Resume is unavailable while enrollment is inactive.",
		}
	}

	if !entitlementAllowed {
		if strings.TrimSpace(entitlementReason) == "" {
			entitlementReason = "missing_entitlement"
		}
		if strings.TrimSpace(entitlementMessage) == "" {
			entitlementMessage = "Your entitlement is missing or inactive for this SCORM course."
		}
		return Doc{
			"allowed":      false,
			"state":        "locked",
			"reason":       entitlementReason,
			"message":      entitlementMessage,
			"progressNote": "Launch is unavailable until the required entitlement is active.",
		}
	}

	if !hasScormCoursePackage(course) {
		return Doc{
			"allowed":      false,
			"state":        "missing_package",
			"reason":       "missing_package",
			"message":      "This SCORM course has no package content to launch yet.",
			"progressNote": "Resume will be available after content and runtime tracking are connected.",
		}
	}

	if len(exports) == 0 {
		return Doc{
			"allowed":      false,
			"state":        "export_not_ready",
			"reason":       "export_not_ready",
			"message":      "A SCORM export has not been generated for this course yet.",
			"progressNote": "Resume placeholders remain visible after an export is available.",
		}
	}

	courseID, _ := asString(course["id"])
	exportID, _ := asString(exports[0]["id"])
	launchURL := "/api/scorm/" + courseID + "/exports"
	if exportID != "" {
		launchURL += "/" + exportID
	}

	resumeEligible := strings.EqualFold(status, "in_progress") || strings.EqualFold(status, "completed")
	progressNote := "Resume will use your last saved SCORM location once runtime tracking is fully integrated."
	if !resumeEligible {
		progressNote = "Progress tracking is not yet connected; start now and a resume point will appear when available."
	}

	return Doc{
		"allowed":         true,
		"state":           "ready",
		"reason":          "",
		"message":         "SCORM package is ready to launch.",
		"launchUrl":       launchURL,
		"resumeAvailable": resumeEligible,
		"progressNote":    progressNote,
	}
}

func isLearnerScormEnrollmentActive(status string) bool {
	normalized := strings.TrimSpace(strings.ToLower(status))
	switch normalized {
	case "", "not_started", "in_progress", "completed", "failed", "enrolled":
		return true
	default:
		return false
	}
}

func hasScormCoursePackage(course Doc) bool {
	raw := course["scos"]
	switch value := raw.(type) {
	case []any:
		return len(value) > 0
	case List:
		return len(value) > 0
	default:
		return false
	}
}