package adapters

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"

	"github.com/missionworkforce/missionmatch/internal/modules/ontology"
)

// NICESource ingests the NIST NICE Workforce Framework for Cybersecurity (SP 800-181 Rev 1)
// components JSON published by the NIST Cybersecurity and Privacy Reference Tool (CPRT).
// It yields one KindWorkRole record per work_role element and one KindKSA record per task,
// knowledge, or skill element. Structural element types (sort, category, competency_area,
// opm_code) are skipped.
type NICESource struct {
	url    string
	client *http.Client
}

// NewNICESource builds the adapter. url is the NICE components JSON location published by NIST CPRT.
func NewNICESource(url string, client *http.Client) *NICESource {
	if client == nil {
		client = &http.Client{Timeout: 120 * time.Second}
	}
	return &NICESource{url: url, client: client}
}

// Name is the provenance label stamped on every record this source yields.
func (s *NICESource) Name() string { return "NICE Framework" }

// Fetch downloads the NICE components JSON and yields one record per work role and TKS element.
func (s *NICESource) Fetch(ctx context.Context, yield func(ontology.VocabRecord) error) error {
	data, err := s.download(ctx)
	if err != nil {
		return err
	}
	recs, err := parseNICE(data)
	if err != nil {
		return err
	}
	for _, r := range recs {
		if err := yield(r); err != nil {
			return err
		}
	}
	return nil
}

func (s *NICESource) download(ctx context.Context) ([]byte, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, s.url, nil)
	if err != nil {
		return nil, fmt.Errorf("nice: new request: %w", err)
	}
	resp, err := s.client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("nice: get: %w", err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("nice: provider returned %s", resp.Status)
	}
	return io.ReadAll(resp.Body)
}

// niceDocument mirrors the top-level shape of the NIST CPRT NICE components JSON
// (v2-2-0_nf_components.json, confirmed from the live file at
// https://csrc.nist.gov/csrc/media/Projects/cprt/documents/nice/v2-2-0_nf_components.json).
type niceDocument struct {
	Elements []niceElement `json:"elements"`
}

// niceElement mirrors one entry in the elements array. The five fields below are the complete
// set present in the real file; element_type values observed are: sort, category, competency_area,
// opm_code, work_role, task, knowledge, skill.
type niceElement struct {
	ElementType       string `json:"element_type"`
	ElementIdentifier string `json:"element_identifier"`
	Title             string `json:"title"`
	Text              string `json:"text"`
	DocIdentifier     string `json:"doc_identifier"`
}

// parseNICE decodes NICE components JSON bytes and returns one VocabRecord per work_role and
// per TKS (task, knowledge, skill) element. All other element types are skipped.
//
// Schema notes confirmed from the live v2-2-0 file:
//
//	work_role: identifier in element_identifier (e.g. OG-WRL-017), name in title, description in text.
//	task: identifier in element_identifier (e.g. T0006), title is empty, description in text.
//	knowledge: identifier in element_identifier (e.g. K0018), title is empty, description in text.
//	skill: identifier in element_identifier (e.g. S0011), title is empty, description in text.
func parseNICE(data []byte) ([]ontology.VocabRecord, error) {
	var doc niceDocument
	if err := json.Unmarshal(data, &doc); err != nil {
		return nil, fmt.Errorf("nice: decode JSON: %w", err)
	}

	out := make([]ontology.VocabRecord, 0, len(doc.Elements))
	for _, el := range doc.Elements {
		id := strings.TrimSpace(el.ElementIdentifier)
		if id == "" {
			continue
		}

		switch el.ElementType {
		case "work_role":
			term := strings.TrimSpace(el.Title)
			if term == "" {
				term = strings.TrimSpace(el.Text)
			}
			if term == "" {
				continue
			}
			raw, _ := json.Marshal(map[string]string{
				"element_type":       el.ElementType,
				"element_identifier": id,
				"title":              el.Title,
				"text":               el.Text,
			})
			out = append(out, ontology.VocabRecord{
				SourceName:     "NICE Framework",
				SourceRecordID: id,
				Kind:           ontology.KindWorkRole,
				Term:           term,
				Code:           id,
				Category:       el.ElementType,
				Description:    strings.TrimSpace(el.Text),
				Raw:            raw,
			})

		case "task", "knowledge", "skill":
			term := strings.TrimSpace(el.Text)
			if term == "" {
				term = strings.TrimSpace(el.Title)
			}
			if term == "" {
				continue
			}
			raw, _ := json.Marshal(map[string]string{
				"element_type":       el.ElementType,
				"element_identifier": id,
				"title":              el.Title,
				"text":               el.Text,
			})
			out = append(out, ontology.VocabRecord{
				SourceName:     "NICE Framework",
				SourceRecordID: id,
				Kind:           ontology.KindKSA,
				Term:           term,
				Code:           id,
				Category:       el.ElementType,
				Description:    term,
				Raw:            raw,
			})

		default:
			// sort, category, competency_area, opm_code and any future structural types are skipped.
		}
	}
	return out, nil
}