package handlers

import (
	"net/http"
	"strconv"
	"strings"
	"time"

	"veola/internal/db"
	"veola/internal/models"
	"veola/internal/scheduler"
	"veola/templates"
)

const resultsPerPage = 20

func (a *App) GetItemResults(w http.ResponseWriter, r *http.Request) {
	id := intParam(r, "id")
	it, err := a.Store.GetItem(r.Context(), id)
	if err != nil || it == nil {
		http.NotFound(w, r)
		return
	}
	page, _ := strconv.Atoi(r.URL.Query().Get("page"))
	d, err := a.buildItemResultsData(r, it, page, r.URL.Query().Get("order"))
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	render(w, r, templates.ItemResults(d))
}

// buildItemResultsData assembles the per-item results view: paginated results,
// price history, badge, and chart JSON. Shared by GetItemResults and the
// "Run Now" handler so both render identical data.
func (a *App) buildItemResultsData(r *http.Request, it *models.Item, page int, order string) (templates.ItemResultsData, error) {
	if order == "" {
		order = "found_desc"
	}
	if page < 1 {
		page = 1
	}

	total, err := a.Store.CountResults(r.Context(), it.ID)
	if err != nil {
		return templates.ItemResultsData{}, err
	}
	totalPages := (total + resultsPerPage - 1) / resultsPerPage
	if totalPages < 1 {
		totalPages = 1
	}
	if page > totalPages {
		page = totalPages
	}

	results, err := a.Store.ListResults(r.Context(), db.ResultsQuery{
		ItemID: it.ID,
		Limit:  resultsPerPage,
		Offset: (page - 1) * resultsPerPage,
		Order:  order,
	})
	if err != nil {
		return templates.ItemResultsData{}, err
	}

	history, err := a.Store.ListPriceHistory(r.Context(), it.ID)
	if err != nil {
		return templates.ItemResultsData{}, err
	}

	return templates.ItemResultsData{
		Page:             a.page(r, it.Name, "items"),
		Item:             *it,
		Badge:            scheduler.PickBadge(*it, history, time.Now()),
		History:          history,
		Results:          results,
		Page_:            page,
		TotalPages:       totalPages,
		Order:            order,
		HistoryChartJSON: buildChartJSON(history),
	}, nil
}

func buildChartJSON(history []models.PricePoint) string {
	c := templates.ChartJSON{
		Labels: make([]string, 0, len(history)),
		Points: make([]float64, 0, len(history)),
	}
	for _, p := range history {
		c.Labels = append(c.Labels, p.PolledAt.Format("2006-01-02"))
		c.Points = append(c.Points, p.Price)
	}
	return templates.MustChartJSON(c)
}

func (a *App) GetGlobalResults(w http.ResponseWriter, r *http.Request) {
	q := r.URL.Query()
	itemID, _ := strconv.ParseInt(q.Get("item_id"), 10, 64)
	from := strings.TrimSpace(q.Get("from"))
	to := strings.TrimSpace(q.Get("to"))

	items, err := a.Store.ListItems(r.Context())
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	names := make(map[int64]string, len(items))
	for _, it := range items {
		names[it.ID] = it.Name
	}

	results, err := a.Store.ListResults(r.Context(), db.ResultsQuery{
		ItemID: itemID,
		Limit:  200,
	})
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	fromT, _ := time.Parse("2006-01-02", from)
	toT, _ := time.Parse("2006-01-02", to)
	if !toT.IsZero() {
		toT = toT.Add(24 * time.Hour)
	}

	rows := make([]templates.ItemResultRow, 0, len(results))
	for _, res := range results {
		if !fromT.IsZero() && res.FoundAt.Before(fromT) {
			continue
		}
		if !toT.IsZero() && !res.FoundAt.Before(toT) {
			continue
		}
		rows = append(rows, templates.ItemResultRow{
			Result:   res,
			ItemName: names[res.ItemID],
		})
	}

	render(w, r, templates.GlobalResults(templates.GlobalResultsData{
		Page:    a.page(r, "Results", "results"),
		Items:   items,
		Results: rows,
		ItemID:  itemID,
		From:    from,
		To:      to,
	}))
}