package recruitment

import (
	"context"
	"crypto/md5"
	"encoding/json"
	"fmt"
	"net/url"
	"regexp"
	"strings"
	"time"

	"github.com/gogf/gf/v2/errors/gerror"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/gtime"

	"service.xpcool.com/internal/dao"
	"service.xpcool.com/internal/model/do"
	"service.xpcool.com/internal/model/dto"
	"service.xpcool.com/internal/model/entity"
)

// crawlerRun 按数据源类型分发抓取，返回运行结果（供写日志/统计）。
func crawlerRun(ctx context.Context, src entity.CrawlSource, force bool) dto.CrawlRunResult {
	res := dto.CrawlRunResult{SourceId: src.Id}
	defer func() {
		// 防止单源解析panic拖垮整体调度。
		if r := recover(); r != nil {
			res.Err = gerror.Newf("crawler panic: %v", r)
		}
	}()
	var (
		infos []dto.RecruitmentInput
		err   error
	)
	switch src.SourceType {
	case 1: // 静态列表页
		infos, err = genericStaticCrawl(ctx, src, force)
	case 2: // SPA / JS 渲染（需底层 JSON 接口，首批 POC）
		infos, err = spaCrawl(ctx, src, force)
	case 3: // 需登录/验证码，首批已排除
		err = gerror.New("该源需登录/验证码，首批已排除")
	case 4: // 附件型，先按静态抓取，附件解析为后续增强
		infos, err = genericStaticCrawl(ctx, src, force)
	default:
		err = gerror.Newf("未知源类型 %d", src.SourceType)
	}
	res.Err = err
	res.Fetched = len(infos)
	if err != nil {
		return res
	}
	newCount, updated := 0, 0
	for i := range infos {
		isNew, e := upsertInfo(ctx, infos[i])
		if e != nil {
			res.Err = e
			continue
		}
		if isNew {
			newCount++
		} else {
			updated++
		}
	}
	res.NewCount = newCount
	res.UpdatedCount = updated
	return res
}

// genericStaticCrawl 通用静态列表抓取：取列表页锚点 → 逐条抓详情 → 抽取字段。
func genericStaticCrawl(ctx context.Context, src entity.CrawlSource, force bool) ([]dto.RecruitmentInput, error) {
	listURL := joinURL(src.BaseUrl, src.ListPath)
	if listURL == "" {
		listURL = src.BaseUrl
	}
	html, err := fetchHTML(ctx, listURL)
	if err != nil {
		return nil, err
	}
	g.Log().Infof(ctx, "[recruit-debug] src=%d listURL=%s htmlLen=%d", src.Id, listURL, len(html))
	raw := extractAnchors(html, listURL)
	anchors := filterArticleAnchors(raw)
	g.Log().Infof(ctx, "[recruit-debug] src=%d rawAnchors=%d filtered=%d", src.Id, len(raw), len(anchors))
	var out []dto.RecruitmentInput
	limit := 60
	if force {
		limit = 300 // 全量回溯放宽上限
	}
	for _, a := range anchors {
		if len(out) >= limit {
			break
		}
		dHtml, e := fetchHTML(ctx, a.URL)
		if e != nil {
			continue
		}
		title, content, pub, dl, ex := extractDetail(dHtml)
		if title == "" {
			title = a.Text
		}
		pubDate := normalizeDate(pub)
		// 增量模式：跳过 30 天前的公告，避免无效回扫。
		if !force && pubDate != "" {
			if t, e2 := time.Parse("2006-01-02", pubDate); e2 == nil {
				if time.Since(t) > 30*24*time.Hour {
					continue
				}
			}
		}
		out = append(out, dto.RecruitmentInput{
			Title:       title,
			SourceId:    src.Id,
			OrgName:     src.Name,
			Category:    src.Category,
			Region:      src.Region,
			PublishDate: pubDate,
			Deadline:    normalizeDate(dl),
			ExamDate:    normalizeDate(ex),
			Url:         a.URL,
			Content:     content,
			Status:      0,
		})
	}
	return out, nil
}

// spaCrawl SPA 源抓取（最佳实践：逆向底层 JSON 接口）。当前为占位实现，
// 若服务端渲染无锚点则返回明确错误，便于在阶段0 POC 中补齐接口。
func spaCrawl(ctx context.Context, src entity.CrawlSource, force bool) ([]dto.RecruitmentInput, error) {
	listURL := joinURL(src.BaseUrl, src.ListPath)
	if listURL == "" {
		listURL = src.BaseUrl
	}
	html, err := fetchHTML(ctx, listURL)
	if err != nil {
		return nil, err
	}
	// 部分 SPA 会在 HTML 内联 __NEXT_DATA__ / 初始 state，可从中抽取。
	if data := extractFromInlineJSON(html); len(data) > 0 {
		return data, nil
	}
	// 纯客户端渲染（hash 路由）无服务端内容，需 POC 接入接口。
	if len(extractAnchors(html, listURL)) == 0 {
		return nil, gerror.New("SPA 无服务端渲染内容，需接入底层 JSON 接口（阶段0 POC）")
	}
	return genericStaticCrawl(ctx, src, force)
}

// extractFromInlineJSON 从 SPA 内联 JSON（__NEXT_DATA__ / window.__INITIAL_STATE__）抽取标题与链接。
// 适配 Vue/Next 等 SSR/CSR 混合页面，作为 SPA 源的兜底解析。
func extractFromInlineJSON(html string) []dto.RecruitmentInput {
	var out []dto.RecruitmentInput
	// 匹配常见内联 JSON 块，逐块扫描其中的标题/链接字段。
	blocks := inlineJSONRe.FindAllStringSubmatch(html, -1)
	for _, b := range blocks {
		raw := b[1]
		var generic map[string]any
		if err := json.Unmarshal([]byte(raw), &generic); err != nil {
			continue
		}
		walkJSON(generic, &out)
	}
	return out
}

// walkJSON 递归遍历内联 JSON，提取含标题与链接的条目（最佳实践，避免硬规则）。
func walkJSON(node any, out *[]dto.RecruitmentInput) {
	switch v := node.(type) {
	case map[string]any:
		title, _ := v["title"].(string)
		link, _ := v["url"].(string)
		if link == "" {
			link, _ = v["href"].(string)
		}
		if title != "" && link != "" {
			*out = append(*out, dto.RecruitmentInput{
				Title: title, Url: link, Status: 0,
			})
		}
		for _, val := range v {
			walkJSON(val, out)
		}
	case []any:
		for _, item := range v {
			walkJSON(item, out)
		}
	}
}

// fetchHTML 带超时与浏览器 UA 的请求，降低被反爬概率。
func fetchHTML(ctx context.Context, u string) (string, error) {
	client := g.Client()
	client.SetTimeout(15 * time.Second)
	client.SetHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0 Safari/537.36")
	client.SetHeader("Accept", "text/html,application/xhtml+xml,*/*")
	resp, err := client.Get(ctx, u)
	if err != nil {
		return "", gerror.Wrapf(err, "fetch %s", u)
	}
	defer resp.Close()
	if resp.StatusCode != 200 {
		return "", gerror.Newf("HTTP %d for %s", resp.StatusCode, u)
	}
	return resp.ReadAllString(), nil
}

type anchor struct {
	URL   string
	Text  string
}

var (
	// anchorBlockRe 匹配完整 <a>...</a> 块；hrefRe/titleAttrRe 从块内分别抽取链接与 title 属性。
	anchorBlockRe = regexp.MustCompile(`(?is)<a\b[^>]*>([\s\S]*?)</a>`)
	hrefRe        = regexp.MustCompile(`(?i)\bhref\s*=\s*["']([^"']+)["']`)
	titleAttrRe   = regexp.MustCompile(`(?i)\btitle\s*=\s*["']([^"']+)["']`)
	tagRe         = regexp.MustCompile(`<[^>]+>`)
	scriptRe      = regexp.MustCompile(`(?is)<script[\s\S]*?</script>`)
	styleRe       = regexp.MustCompile(`(?is)<style[\s\S]*?</style>`)
	titleRe       = regexp.MustCompile(`(?is)<title[^>]*>([\s\S]*?)</title>`)
	h1Re          = regexp.MustCompile(`(?is)<h1[^>]*>([\s\S]*?)</h1>`)
	dateRe        = regexp.MustCompile(`(\d{4})[-/年.](\d{1,2})[-/月.](\d{1,2})`)
	inlineJSONRe  = regexp.MustCompile(`(?is)(?:__NEXT_DATA__|__INITIAL_STATE__|window\.__[A-Z_]+)\s*=\s*(\{[\s\S]*?\})\s*;?`)
	spaceRe       = regexp.MustCompile(`\s+`)
	// recruitKw 招聘类公告常见语义词，用于从政府站链接中识别公告条目。
	recruitKw = regexp.MustCompile(`招聘|招考|公招|选聘|引进|人才|公告|公示|录用|录取|面试|笔试|报名|选调|遴选|拟聘|聘用|招募|招录|考试|考录|体检|考察|资格复审|递补`)
)

// extractAnchors 从 HTML 抽取绝对化后的锚点（URL + 文本）。
// 政府站常把真实标题放在 title 属性、inner text 仅"详细/更多"，故 inner 过短时回退 title。
func extractAnchors(html, base string) []anchor {
	out := make([]anchor, 0)
	for _, block := range anchorBlockRe.FindAllStringSubmatch(html, -1) {
		full := block[0]
		hm := hrefRe.FindStringSubmatch(full)
		if len(hm) < 2 {
			continue
		}
		href := strings.TrimSpace(hm[1])
		if href == "" || strings.HasPrefix(href, "javascript:") ||
			strings.HasPrefix(href, "#") || strings.HasPrefix(href, "mailto:") {
			continue
		}
		inner := strings.TrimSpace(stripTags(block[1]))
		text := inner
		if tm := titleAttrRe.FindStringSubmatch(full); len(tm) >= 2 {
			t := strings.TrimSpace(tm[1])
			if len([]rune(text)) < 4 && t != "" {
				text = t
			}
		}
		if text == "" {
			continue
		}
		abs := resolveURL(base, href)
		if abs == "" {
			continue
		}
		out = append(out, anchor{URL: abs, Text: text})
	}
	return out
}

// filterArticleAnchors 过滤导航/无用链接，保留疑似招聘公告条目并去重。
func filterArticleAnchors(as []anchor) []anchor {
	out := make([]anchor, 0, len(as))
	for _, a := range as {
		text := strings.TrimSpace(a.Text)
		if len([]rune(text)) < 4 {
			continue
		}
		u := strings.ToLower(a.URL)
		// URL 形态线索：静态详情页、政务公开/人事招考栏目、含年份。
		urlHint := strings.Contains(u, ".html") || strings.Contains(u, ".shtml") ||
			strings.Contains(u, ".php") || strings.Contains(u, "/tzgg") ||
			strings.Contains(u, "/rszk") || strings.Contains(u, "/rsxx") ||
			strings.Contains(u, "/zfxx") || dateRe.MatchString(a.URL)
		// 文本语义线索：政府站公告标题常含这些词（必须命中，过滤"市长信箱/重点领域"等非招聘页）。
		textHint := recruitKw.MatchString(text) || recruitKw.MatchString(a.URL)
		// 同时满足"内容页形态"与"招聘语义"，避免误抓栏目/互动页。
		if urlHint && textHint {
			out = append(out, a)
		}
	}
	seen := map[string]bool{}
	uniq := out[:0]
	for _, a := range out {
		if seen[a.URL] {
			continue
		}
		seen[a.URL] = true
		uniq = append(uniq, a)
	}
	return uniq
}

// extractDetail 从详情页抽取标题/正文/发布日期/报名截止/笔试日期（启发式，可按源调优）。
func extractDetail(html string) (title, content, publishDate, deadline, examDate string) {
	if m := titleRe.FindStringSubmatch(html); len(m) > 1 {
		title = stripTags(m[1])
	}
	if title == "" {
		if m := h1Re.FindStringSubmatch(html); len(m) > 1 {
			title = stripTags(m[1])
		}
	}
	title = strings.TrimSpace(title)
	body := scriptRe.ReplaceAllString(html, " ")
	body = styleRe.ReplaceAllString(body, " ")
	text := stripTags(body)
	text = collapseSpace(text)
	if len([]rune(text)) > 4000 {
		text = string([]rune(text)[:4000])
	}
	content = text
	publishDate = normalizeDate(firstDate(html))
	deadline = normalizeDate(findDateAfter(text, "报名"))
	examDate = normalizeDate(findDateAfter(text, "笔试"))
	return
}

// firstDate 返回文本中首个日期（归一化后）。
func firstDate(s string) string {
	m := dateRe.FindStringSubmatch(s)
	if len(m) == 0 {
		return ""
	}
	return normalizeDate(m[0])
}

// findDateAfter 在 keyword 之后查找下一个日期（用于报名/笔试时间）。
func findDateAfter(text, keyword string) string {
	idx := strings.Index(text, keyword)
	if idx < 0 {
		return ""
	}
	rest := text[idx:]
	m := dateRe.FindStringSubmatch(rest)
	if len(m) == 0 {
		return ""
	}
	return normalizeDate(m[0])
}

// normalizeDate 将多种中文/西式日期归一化为 YYYY-MM-DD。
func normalizeDate(s string) string {
	s = strings.TrimSpace(s)
	if s == "" {
		return ""
	}
	m := dateRe.FindStringSubmatch(s)
	if len(m) == 0 {
		return ""
	}
	y, mo, d := m[1], atoiSafe(m[2]), atoiSafe(m[3])
	return fmt.Sprintf("%s-%02d-%02d", y, mo, d)
}

// stripTags 去除 HTML 标签。
func stripTags(s string) string {
	return tagRe.ReplaceAllString(s, " ")
}

// collapseSpace 折叠空白字符。
func collapseSpace(s string) string {
	return spaceRe.ReplaceAllString(s, " ")
}

// resolveURL 将相对链接解析为绝对 URL。
func resolveURL(base, href string) string {
	if strings.HasPrefix(href, "http://") || strings.HasPrefix(href, "https://") {
		return href
	}
	u, err := url.Parse(base)
	if err != nil {
		return ""
	}
	ref, err := url.Parse(href)
	if err != nil {
		return ""
	}
	return u.ResolveReference(ref).String()
}

// joinURL 拼接基础域名与路径。
func joinURL(base, p string) string {
	if p == "" {
		return base
	}
	if strings.HasPrefix(p, "http") {
		return p
	}
	u, err := url.Parse(base)
	if err != nil {
		return base + p
	}
	ref, err := url.Parse(p)
	if err != nil {
		return base + p
	}
	return u.ResolveReference(ref).String()
}

func atoiSafe(s string) int {
	n := 0
	for _, c := range s {
		if c < '0' || c > '9' {
			break
		}
		n = n*10 + int(c-'0')
	}
	return n
}

// ---------- 去重与写入 ----------

func fingerprintOf(in dto.RecruitmentInput) string {
	h := md5.Sum([]byte(fmt.Sprintf("%d|%s|%s|%s", in.SourceId, in.Title, in.PublishDate, in.Url)))
	return fmt.Sprintf("%x", h)
}

func groupKeyOf(in dto.RecruitmentInput) string {
	h := md5.Sum([]byte(fmt.Sprintf("%s|%s", in.Title, in.PublishDate)))
	return fmt.Sprintf("%x", h)
}

// upsertInfo 按指纹去重写入公告；已存在则更新可变字段（内容/状态/日期）。
func upsertInfo(ctx context.Context, in dto.RecruitmentInput) (bool, error) {
	if in.Fingerprint == "" {
		in.Fingerprint = fingerprintOf(in)
	}
	if in.GroupKey == "" {
		in.GroupKey = groupKeyOf(in)
	}
	var exist entity.RecruitmentInfo
	if err := dao.RecruitmentInfo.Ctx(ctx).Where("fingerprint", in.Fingerprint).Scan(&exist); err != nil {
		// gf 的 Scan 在查无记录时返回 "no rows" 错误，视为未存在，继续插入。
		if !strings.Contains(err.Error(), "no rows") {
			return false, gerror.Wrap(err, "query exist info")
		}
	}
	if exist.Id > 0 {
		_, err := dao.RecruitmentInfo.Ctx(ctx).Where("id", exist.Id).Data(do.RecruitmentInfo{
			Content: in.Content, Status: in.Status, Deadline: in.Deadline,
			ExamDate: in.ExamDate, UpdatedAt: gtime.Now(),
		}).Update()
		if err != nil {
			return false, gerror.Wrap(err, "update info")
		}
		return false, nil
	}
	orgId, err := upsertOrg(ctx, in.OrgName, in.Category, in.Region)
	if err != nil {
		return false, err
	}
	in.OrgId = orgId
	if _, err = dao.RecruitmentInfo.Ctx(ctx).Data(toRecruitmentDO(in)).InsertAndGetId(); err != nil {
		return false, gerror.Wrap(err, "insert info")
	}
	return true, nil
}

// upsertOrg 发布主体按名称去重，返回主键。
func upsertOrg(ctx context.Context, name string, category int, region string) (uint64, error) {
	if name == "" {
		return 0, nil
	}
	var org entity.Organization
	if err := dao.Organization.Ctx(ctx).Where("name", name).Scan(&org); err != nil {
		if !strings.Contains(err.Error(), "no rows") {
			return 0, gerror.Wrap(err, "query org")
		}
	}
	if org.Id > 0 {
		return org.Id, nil
	}
	id, err := dao.Organization.Ctx(ctx).Data(do.Organization{
		Name: name, Type: mapCategoryToOrgType(category), Region: region,
		CreatedAt: gtime.Now(), UpdatedAt: gtime.Now(),
	}).InsertAndGetId()
	if err != nil {
		return 0, gerror.Wrap(err, "insert org")
	}
	return uint64(id), nil
}

func mapCategoryToOrgType(c int) int {
	switch c {
	case 2:
		return 2 // 事业单位
	case 3:
		return 3 // 国企
	case 4:
		return 4 // 央企
	case 5:
		return 5 // 私企
	default:
		return 6
	}
}

func toRecruitmentDO(in dto.RecruitmentInput) do.RecruitmentInfo {
	now := gtime.Now()
	return do.RecruitmentInfo{
		Title: in.Title, SourceId: in.SourceId, OrgId: in.OrgId, OrgName: in.OrgName,
		Category: in.Category, Region: in.Region, PublishDate: nullIfEmpty(in.PublishDate),
		Deadline: nullIfEmpty(in.Deadline), ExamDate: nullIfEmpty(in.ExamDate), Url: in.Url, Content: in.Content,
		Attachments: in.Attachments, Status: in.Status, Fingerprint: in.Fingerprint,
		GroupKey: in.GroupKey, CreatedAt: now, UpdatedAt: now,
	}
}

// nullIfEmpty 将空字符串转为 nil，便于插入 NULL（DATE 等可空列不接受空串）。
func nullIfEmpty(s string) any {
	if strings.TrimSpace(s) == "" {
		return nil
	}
	return s
}

// recordCrawlLog 写抓取日志并更新数据源运行状态（成功清失败计数；失败累加）。
func recordCrawlLog(ctx context.Context, res dto.CrawlRunResult) {
	errMsg := ""
	if res.Err != nil {
		// 错误可能含整页 SQL，截断避免超过 error 列长度导致日志也写不进。
		errMsg = res.Err.Error()
		const maxErr = 900
		if len(errMsg) > maxErr {
			errMsg = errMsg[:maxErr] + "...(truncated)"
		}
	}
	if _, err := dao.CrawlLog.Ctx(ctx).Data(do.CrawlLog{
		SourceId: res.SourceId, RunAt: gtime.Now(), Fetched: res.Fetched,
		NewCount: res.NewCount, UpdatedCount: res.UpdatedCount, Error: errMsg,
	}).Insert(); err != nil {
		g.Log().Errorf(ctx, "write crawl log failed: %v", err)
	}
	if res.Err != nil {
		var src entity.CrawlSource
		_ = dao.CrawlSource.Ctx(ctx).Where("id", res.SourceId).Scan(&src)
		_, _ = dao.CrawlSource.Ctx(ctx).Where("id", res.SourceId).
			Data(do.CrawlSource{FailCount: src.FailCount + 1}).Update()
		return
	}
	_, _ = dao.CrawlSource.Ctx(ctx).Where("id", res.SourceId).
		Data(do.CrawlSource{LastSuccessAt: gtime.Now().String(), FailCount: 0}).Update()
}

// ---------- 订阅辅助 ----------

// loadSubscription 加载推送订阅：id>0 按 id；否则取首个启用订阅。
func loadSubscription(ctx context.Context, id uint64) (*entity.PushSubscription, error) {
	var sub entity.PushSubscription
	m := dao.PushSubscription.Ctx(ctx)
	if id > 0 {
		m = m.Where("id", id)
	} else {
		m = m.Where("enabled", 1)
	}
	if err := m.OrderDesc("id").Scan(&sub); err != nil {
		return nil, gerror.Wrap(err, "query subscription")
	}
	if sub.Id == 0 {
		return nil, nil
	}
	return &sub, nil
}

func doPushSubscription(in dto.SubscriptionInput) do.PushSubscription {
	regions, _ := json.Marshal(in.Regions)
	cats, _ := json.Marshal(in.Categories)
	return do.PushSubscription{
		Name: in.Name, DeviceKey: in.DeviceKey, Regions: string(regions),
		Categories: string(cats), OnlyNew: in.OnlyNew, PushTime: in.PushTime,
		Enabled: in.Enabled, UpdatedAt: gtime.Now(),
	}
}

func parseJSONStrings(s string) []string {
	if s == "" {
		return nil
	}
	var out []string
	_ = json.Unmarshal([]byte(s), &out)
	return out
}

func parseJSONInts(s string) []int {
	if s == "" {
		return nil
	}
	var out []int
	_ = json.Unmarshal([]byte(s), &out)
	return out
}