package marketing

import (
	"context"
	"encoding/json"
	"fmt"
	"sort"
	"time"

	"github.com/descrybe/descrybe-v2/apps/api/internal/feeds"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5/pgxpool"
)

// PreparedCampaign is a seasonal preset linked to an export feed.
type PreparedCampaign struct {
	PresetID       PresetID `json:"preset_id"`
	Name           string   `json:"name"`
	StartDate      string   `json:"start_date"`
	EndDate        string   `json:"end_date"`
	Year           int      `json:"year"`
	ExportFeedID   string   `json:"export_feed_id"`
	ExportFeedName string   `json:"export_feed_name"`
	Created        bool     `json:"created"`
}

// Service prepares content-calendar campaigns via export feeds (no new tables).
type Service struct {
	Pool  *pgxpool.Pool
	Feeds *feeds.Service
}

// Cap matches httpapi maxPageLimit; seasonal presets over years stay well under this.
const maxPreparedCampaigns = 200

// listPreparedCampaignsSQL filters to campaign feeds in SQL (jsonb key) and caps rows.
const listPreparedCampaignsSQL = `
		SELECT id, name, template
		FROM export_feeds
		WHERE company_id = $1
			AND template ? $2
		ORDER BY created_at DESC
		LIMIT $3`

// ListPreparedCampaigns finds export feeds whose template contains _campaign meta.
func (s *Service) ListPreparedCampaigns(ctx context.Context, companyID uuid.UUID) ([]PreparedCampaign, error) {
	rows, err := s.Pool.Query(ctx, listPreparedCampaignsSQL, companyID, CampaignStructureKey, maxPreparedCampaigns)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	out := make([]PreparedCampaign, 0)
	for rows.Next() {
		var id uuid.UUID
		var name string
		var tpl []byte
		if err := rows.Scan(&id, &name, &tpl); err != nil {
			return nil, err
		}
		meta, ok := readCampaignMeta(tpl)
		if !ok {
			continue
		}
		out = append(out, PreparedCampaign{
			PresetID:       meta.PresetID,
			Name:           meta.Name,
			StartDate:      meta.StartDate,
			EndDate:        meta.EndDate,
			Year:           meta.Year,
			ExportFeedID:   id.String(),
			ExportFeedName: name,
			Created:        false,
		})
	}
	if err := rows.Err(); err != nil {
		return nil, err
	}
	sort.Slice(out, func(i, j int) bool {
		return out[i].StartDate < out[j].StartDate
	})
	return out, nil
}

// PrepareInput creates or reuses a seasonal export feed.
type PrepareInput struct {
	PresetID PresetID
	Year     int
	Format   string
	ForceNew bool
}

// PrepareCampaign creates (or reuses) a CSV/XML export feed for a seasonal preset.
func (s *Service) PrepareCampaign(ctx context.Context, companyID uuid.UUID, in PrepareInput) (PreparedCampaign, error) {
	year := in.Year
	if year == 0 {
		year = time.Now().UTC().Year()
	}
	preset, err := ResolvePreset(in.PresetID, year)
	if err != nil {
		return PreparedCampaign{}, err
	}
	format := in.Format
	if format == "" {
		format = "csv"
	}
	if format != "csv" && format != "xml" {
		return PreparedCampaign{}, ClientMsg("format must be csv or xml")
	}

	if !in.ForceNew {
		existing, err := s.ListPreparedCampaigns(ctx, companyID)
		if err != nil {
			return PreparedCampaign{}, err
		}
		for _, c := range existing {
			if c.PresetID == in.PresetID && c.Year == year {
				c.Created = false
				return c, nil
			}
		}
	}

	meta := StructureMeta{
		PresetID:   preset.ID,
		Name:       preset.Name,
		StartDate:  preset.StartDate,
		EndDate:    preset.EndDate,
		Year:       preset.Year,
		PreparedAt: time.Now().UTC().Format(time.RFC3339),
	}
	template := map[string]any{
		CampaignStructureKey: meta,
		"mappings":           DefaultCampaignMappings(),
	}
	if format == "xml" {
		template["root"] = "rss"
		template["item"] = "channel/item"
	}

	feedName := fmt.Sprintf("%s %d", preset.Name, year)
	created, err := s.Feeds.CreateExportFeed(ctx, companyID, feeds.CreateExportInput{
		Name:     feedName,
		Format:   format,
		Template: template,
		Filters:  map[string]any{"statuses": []string{"completed"}},
	})
	if err != nil {
		return PreparedCampaign{}, err
	}

	id, _ := created["id"].(uuid.UUID)
	name, _ := created["name"].(string)
	if name == "" {
		name = feedName
	}
	return PreparedCampaign{
		PresetID:       preset.ID,
		Name:           preset.Name,
		StartDate:      preset.StartDate,
		EndDate:        preset.EndDate,
		Year:           preset.Year,
		ExportFeedID:   id.String(),
		ExportFeedName: name,
		Created:        true,
	}, nil
}

func readCampaignMeta(raw []byte) (StructureMeta, bool) {
	if len(raw) == 0 || string(raw) == "{}" || string(raw) == "null" {
		return StructureMeta{}, false
	}
	var root map[string]any
	if err := json.Unmarshal(raw, &root); err != nil {
		return StructureMeta{}, false
	}
	metaRaw, ok := root[CampaignStructureKey]
	if !ok || metaRaw == nil {
		return StructureMeta{}, false
	}
	b, err := json.Marshal(metaRaw)
	if err != nil {
		return StructureMeta{}, false
	}
	var meta StructureMeta
	if err := json.Unmarshal(b, &meta); err != nil {
		return StructureMeta{}, false
	}
	if meta.PresetID == "" || meta.StartDate == "" || meta.EndDate == "" {
		return StructureMeta{}, false
	}
	return meta, true
}