package handlers

import (
	"archive/zip"
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"path"
	"strings"
	"time"

	"github.com/flatrender/render-svc/internal/aep"
	"github.com/flatrender/render-svc/internal/db"
	"github.com/flatrender/render-svc/internal/models"
	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
	"github.com/minio/minio-go/v7"
)

// ScanHandler exposes the headless Go "quick scan" and the async AE scan-job
// lifecycle. Both produce the same ScanResult shape the content importer consumes.
type ScanHandler struct {
	store           *db.Store
	minio           *minio.Client
	templatesBucket string
}

func NewScanHandler(store *db.Store, mc *minio.Client, templatesBucket string) *ScanHandler {
	return &ScanHandler{store: store, minio: mc, templatesBucket: templatesBucket}
}

// ── ScanResult shape (matches content-svc) ────────────────────────────────────
type scanColor struct {
	ElementKey   string `json:"element_key"`
	Title        string `json:"title"`
	AttrValue    string `json:"attr_value"`
	DefaultColor string `json:"default_color"`
	Sort         int    `json:"sort"`
}
type scanScene struct {
	Key                string        `json:"key"`
	Title              string        `json:"title"`
	SceneType          string        `json:"scene_type"`
	DefaultDurationSec *float64      `json:"default_duration_sec,omitempty"`
	Sort               int           `json:"sort"`
	Elements           []interface{} `json:"elements"`
	Colors             []scanColor   `json:"colors"`
}
type scanResult struct {
	Source       string      `json:"source"`
	RenderComp   string      `json:"render_comp,omitempty"`
	Scenes       []scanScene `json:"scenes"`
	SharedColors []scanColor `json:"shared_colors"`
}

// reserved comp names that are not scenes.
func isReservedComp(name string) bool {
	switch strings.ToLower(name) {
	case "frfinal", "frshare", "all":
		return true
	}
	return false
}

// ── Quick scan (headless, no AE) ──────────────────────────────────────────────
// POST /v1/template-scans/:project_id/quick
func (h *ScanHandler) QuickScan(c *gin.Context) {
	pid, err := uuid.Parse(c.Param("project_id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid project_id"})
		return
	}
	if h.minio == nil {
		c.JSON(http.StatusServiceUnavailable, models.APIError{Code: "no_storage", Message: "object storage not configured"})
		return
	}
	ctx, cancel := context.WithTimeout(c.Request.Context(), 60*time.Second)
	defer cancel()

	data, err := h.loadAep(ctx, pid)
	if err != nil {
		c.JSON(http.StatusNotFound, models.APIError{Code: "no_template", Message: err.Error()})
		return
	}
	comps, err := aep.ParseComps(data)
	if err != nil {
		c.JSON(http.StatusUnprocessableEntity, models.APIError{Code: "parse_failed", Message: err.Error()})
		return
	}

	res := scanResult{Source: "go-parser", Scenes: []scanScene{}, SharedColors: []scanColor{}}
	for _, comp := range comps {
		if strings.EqualFold(comp.Name, "frfinal") {
			res.RenderComp = "frfinal"
		}
		if isReservedComp(comp.Name) {
			continue
		}
		sc := scanScene{
			Key: comp.Name, Title: comp.Name, SceneType: "Normal",
			Sort: len(res.Scenes), Elements: []interface{}{}, Colors: []scanColor{},
		}
		if comp.DurationSec > 0 {
			d := comp.DurationSec
			sc.DefaultDurationSec = &d
		}
		res.Scenes = append(res.Scenes, sc)
	}
	c.JSON(http.StatusOK, res)
}

// loadAep fetches the project's template .aep bytes from MinIO — directly when a
// raw .aep was uploaded, or by extracting the .aep from the .zip bundle.
func (h *ScanHandler) loadAep(ctx context.Context, pid uuid.UUID) ([]byte, error) {
	tryGet := func(key string) ([]byte, bool) {
		if _, err := h.minio.StatObject(ctx, h.templatesBucket, key, minio.StatObjectOptions{}); err != nil {
			return nil, false
		}
		obj, err := h.minio.GetObject(ctx, h.templatesBucket, key, minio.GetObjectOptions{})
		if err != nil {
			return nil, false
		}
		defer obj.Close()
		b, rerr := io.ReadAll(obj)
		if rerr != nil || len(b) == 0 {
			return nil, false
		}
		return b, true
	}

	if b, ok := tryGet(fmt.Sprintf("templates/%s/template.aep", pid)); ok {
		return b, nil
	}
	if zb, ok := tryGet(fmt.Sprintf("templates/%s/bundle.zip", pid)); ok {
		return extractAepFromZip(zb)
	}
	return nil, errors.New("no .aep template uploaded for this project (a raw .aepx can only be read by the AE scan)")
}

func extractAepFromZip(zb []byte) ([]byte, error) {
	zr, err := zip.NewReader(bytes.NewReader(zb), int64(len(zb)))
	if err != nil {
		return nil, fmt.Errorf("open bundle: %w", err)
	}
	var best *zip.File
	bestDepth := 1 << 30
	for _, f := range zr.File {
		base := path.Base(f.Name)
		if strings.HasPrefix(base, "._") || strings.Contains(f.Name, "__MACOSX") {
			continue
		}
		if strings.ToLower(path.Ext(f.Name)) == ".aep" {
			depth := strings.Count(f.Name, "/")
			if depth < bestDepth {
				bestDepth = depth
				best = f
			}
		}
	}
	if best == nil {
		return nil, errors.New("no .aep file found inside the bundle")
	}
	rc, err := best.Open()
	if err != nil {
		return nil, err
	}
	defer rc.Close()
	return io.ReadAll(rc)
}

// ── AE scan jobs (async, full fidelity) ───────────────────────────────────────
// POST /v1/template-scans/:project_id/jobs  (admin)
func (h *ScanHandler) CreateJob(c *gin.Context) {
	pid, err := uuid.Parse(c.Param("project_id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid project_id"})
		return
	}
	id, err := h.store.CreateScanJob(c.Request.Context(), pid, "ae-jsx")
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"id": id, "status": "queued"})
}

// GET /v1/template-scan-jobs/:id  (admin)
func (h *ScanHandler) GetJob(c *gin.Context) {
	id, err := uuid.Parse(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid id"})
		return
	}
	j, err := h.store.GetScanJob(c.Request.Context(), id)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}
	if j == nil {
		c.JSON(http.StatusNotFound, models.APIError{Code: "not_found", Message: "scan job not found"})
		return
	}
	c.JSON(http.StatusOK, j)
}

// ── internal (node agents, HMAC) ──────────────────────────────────────────────
// POST /v1/internal/scan/claim
func (h *ScanHandler) Claim(c *gin.Context) {
	var req models.ClaimJobRequest
	_ = c.ShouldBindJSON(&req)

	claim, err := h.store.ClaimScanJob(c.Request.Context(), req.NodeID)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}
	if claim == nil {
		c.Status(http.StatusNoContent)
		return
	}
	url, isBundle, md5 := resolveTemplateObject(h.minio, h.templatesBucket, claim.ProjectID)
	c.JSON(http.StatusOK, gin.H{
		"scan_job_id":      claim.ID,
		"project_id":       claim.ProjectID,
		"aep_download_url": url,
		"is_bundle":        isBundle,
		"bundle_md5":       md5,
	})
}

// POST /v1/internal/scan/:id/result   body = ScanResult JSON
func (h *ScanHandler) Result(c *gin.Context) {
	id, err := uuid.Parse(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid id"})
		return
	}
	body, err := io.ReadAll(c.Request.Body)
	if err != nil || !json.Valid(body) {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "result must be valid JSON"})
		return
	}
	if err := h.store.SetScanResult(c.Request.Context(), id, string(body)); err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}
	c.Status(http.StatusNoContent)
}

// POST /v1/internal/scan/:id/fail   body {reason}
func (h *ScanHandler) Fail(c *gin.Context) {
	id, err := uuid.Parse(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid id"})
		return
	}
	var req struct {
		Reason string `json:"reason"`
	}
	_ = c.ShouldBindJSON(&req)
	if req.Reason == "" {
		req.Reason = "scan failed"
	}
	if err := h.store.SetScanError(c.Request.Context(), id, req.Reason); err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}
	c.Status(http.StatusNoContent)
}

// resolveTemplateObject presigns the canonical template object for a project,
// probing bundle.zip → template.aep → template.aepx (same order as render claim).
func resolveTemplateObject(mc *minio.Client, bucket string, projectID uuid.UUID) (url string, isBundle bool, md5 string) {
	if mc == nil {
		return "", false, ""
	}
	candidates := []struct {
		name   string
		bundle bool
	}{
		{"bundle.zip", true},
		{"template.aep", false},
		{"template.aepx", false},
	}
	for _, cand := range candidates {
		key := fmt.Sprintf("templates/%s/%s", projectID, cand.name)
		info, serr := mc.StatObject(context.Background(), bucket, key, minio.StatObjectOptions{})
		if serr != nil {
			continue
		}
		purl, perr := mc.PresignedGetObject(context.Background(), bucket, key, 2*time.Hour, nil)
		if perr != nil {
			continue
		}
		return purl.String(), cand.bundle, strings.Trim(info.ETag, "\"")
	}
	return "", false, ""
}