package sourcing

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

// PDLBase is the People Data Labs v5 person search endpoint.
const PDLBase = "https://api.peopledatalabs.com/v5/person/search"

// ErrThrottled is returned on a 429 from the sourcing provider.
var ErrThrottled = errors.New("sourcing: rate limited (429)")

// PDL is the People Data Labs Provider. includeContact controls whether email and phone are kept.
type PDL struct {
	key            string
	base           string
	includeContact bool
	http           *http.Client
}

// NewPDL builds the provider. An empty base uses the public endpoint.
func NewPDL(key, base string, includeContact bool) *PDL {
	if strings.TrimSpace(base) == "" {
		base = PDLBase
	}
	return &PDL{key: key, base: base, includeContact: includeContact, http: &http.Client{Timeout: 45 * time.Second}}
}

func (p *PDL) Name() string { return "People Data Labs" }

// Search runs one person search and normalizes the results.
func (p *PDL) Search(ctx context.Context, q SearchQuery) ([]SourcedPerson, error) {
	size := q.Size
	if size < 1 {
		size = 10
	}
	payload, err := json.Marshal(map[string]any{"query": q.ESQuery, "size": size})
	if err != nil {
		return nil, fmt.Errorf("sourcing: marshal request: %w", err)
	}
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, p.base, bytes.NewReader(payload))
	if err != nil {
		return nil, errors.New("sourcing: failed to build request")
	}
	req.Header.Set("X-Api-Key", p.key)
	req.Header.Set("Content-Type", "application/json")

	resp, err := p.http.Do(req)
	if err != nil {
		return nil, errors.New("sourcing: request failed")
	}
	defer func() { _ = resp.Body.Close() }()

	if resp.StatusCode == http.StatusTooManyRequests {
		return nil, ErrThrottled
	}
	if resp.StatusCode != http.StatusOK {
		snippet, _ := io.ReadAll(io.LimitReader(resp.Body, 512))
		return nil, fmt.Errorf("sourcing: status %d: %s", resp.StatusCode, strings.TrimSpace(string(snippet)))
	}

	var r pdlResponse
	if err := json.NewDecoder(resp.Body).Decode(&r); err != nil {
		return nil, fmt.Errorf("sourcing: decode response: %w", err)
	}

	out := make([]SourcedPerson, 0, len(r.Data))
	for _, raw := range r.Data {
		sp, ok := p.normalize(raw)
		if !ok {
			continue
		}
		out = append(out, sp)
	}
	return out, nil
}

// normalize uses map based extraction because PDL data is messy: location_name can be a boolean,
// inferred_years_experience can be a float, and contact arrays vary. Type tolerant helpers keep a
// single odd field from dropping an otherwise good record.
func (p *PDL) normalize(raw json.RawMessage) (SourcedPerson, bool) {
	var m map[string]any
	if err := json.Unmarshal(raw, &m); err != nil {
		return SourcedPerson{}, false
	}
	id := strings.TrimSpace(asString(m["id"]))
	name := strings.TrimSpace(asString(m["full_name"]))
	if id == "" || name == "" {
		return SourcedPerson{}, false
	}
	sp := SourcedPerson{
		ExternalID: id,
		FullName:   name,
		JobTitle:   strings.TrimSpace(asString(m["job_title"])),
		Role:       strings.TrimSpace(asString(m["job_title_role"])),
		Location:   strings.TrimSpace(asString(m["location_name"])),
		Skills:     asStringSlice(m["skills"]),
		Years:      asInt(m["inferred_years_experience"]),
		Raw:        raw,
	}
	if p.includeContact {
		sp.Emails = emailAddresses(m["emails"])
		sp.Phones = asStringSlice(m["phone_numbers"])
	}
	return sp, true
}

type pdlResponse struct {
	Status int               `json:"status"`
	Total  int               `json:"total"`
	Data   []json.RawMessage `json:"data"`
	Error  json.RawMessage   `json:"error"`
}

func asString(v any) string {
	if s, ok := v.(string); ok {
		return s
	}
	return ""
}

func asInt(v any) int {
	switch n := v.(type) {
	case float64:
		if n > 0 {
			return int(n)
		}
	case string:
		var i int
		if _, err := fmt.Sscanf(n, "%d", &i); err == nil && i > 0 {
			return i
		}
	}
	return 0
}

func asStringSlice(v any) []string {
	arr, ok := v.([]any)
	if !ok {
		return nil
	}
	out := make([]string, 0, len(arr))
	for _, e := range arr {
		if s, ok := e.(string); ok && s != "" {
			out = append(out, s)
		}
	}
	return out
}

func emailAddresses(v any) []string {
	arr, ok := v.([]any)
	if !ok {
		return nil
	}
	var out []string
	for _, e := range arr {
		if m, ok := e.(map[string]any); ok {
			if a := asString(m["address"]); a != "" {
				out = append(out, a)
			}
		}
	}
	return out
}