package handlers

import (
	"context"
	"fmt"
	"net/http"
	"net/url"
	"path"
	"strings"
	"time"

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

// TemplateBundleHandler stores the canonical After Effects template object for a
// project. Each project has ONE template at a deterministic per-project key, and
// every render of that project reuses it. The source may be a plain .aep/.aepx or
// a .zip bundle (the .aep plus its footage/fonts) — the node agent extracts zips.
type TemplateBundleHandler struct {
	minio           *minio.Client
	templatesBucket string
}

func NewTemplateBundleHandler(mc *minio.Client, templatesBucket string) *TemplateBundleHandler {
	return &TemplateBundleHandler{minio: mc, templatesBucket: templatesBucket}
}

type setBundleRequest struct {
	// SourceURL is the public/path-style MinIO URL of the freshly uploaded file,
	// e.g. http://host:9000/user-uploads/uploads/<uid>/<uuid>.zip
	SourceURL string `json:"source_url" binding:"required"`
}

type setBundleResponse struct {
	Bucket   string `json:"bucket"`
	Key      string `json:"key"`
	MD5      string `json:"md5"`
	Size     int64  `json:"size_bytes"`
	IsBundle bool   `json:"is_bundle"`
}

// POST /v1/template-bundles/:project_id
// Copies an uploaded .aep/.aepx/.zip into templates/{project_id}/(bundle.zip|
// template.aep|template.aepx) via a server-side MinIO copy (same backend, no
// proxy through this service), then returns the stored key + md5 so the caller
// can record it on the project. Replacing a template overwrites the same key, so
// in-flight and future renders pick up the new bundle (md5 changes → nodes refetch).
func (h *TemplateBundleHandler) Set(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
	}
	var req setBundleRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: err.Error()})
		return
	}
	if h.minio == nil {
		c.JSON(http.StatusServiceUnavailable, models.APIError{Code: "no_storage", Message: "object storage not configured"})
		return
	}

	srcBucket, srcKey, err := parseObjectURL(req.SourceURL)
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_source", Message: err.Error()})
		return
	}

	ext := strings.ToLower(path.Ext(srcKey))
	isBundle := ext == ".zip"
	destName := "template.aep"
	switch ext {
	case ".zip":
		destName = "bundle.zip"
	case ".aepx":
		destName = "template.aepx"
	default: // .aep or unknown — treat as a raw project file
		destName = "template.aep"
	}
	destKey := fmt.Sprintf("templates/%s/%s", pid, destName)

	ctx, cancel := context.WithTimeout(c.Request.Context(), 10*time.Minute)
	defer cancel()

	// The templates bucket may not exist on a fresh deployment — create it (private;
	// the node downloads via presigned URL, so no public policy is needed).
	if exists, berr := h.minio.BucketExists(ctx, h.templatesBucket); berr == nil && !exists {
		if merr := h.minio.MakeBucket(ctx, h.templatesBucket, minio.MakeBucketOptions{}); merr != nil {
			// A concurrent request may have created it — only fail if it's still missing.
			if ex2, _ := h.minio.BucketExists(ctx, h.templatesBucket); !ex2 {
				c.JSON(http.StatusBadGateway, models.APIError{Code: "bucket_error", Message: merr.Error()})
				return
			}
		}
	}

	// Drop any stale sibling in the other format so the claim probe (which checks
	// bundle.zip → template.aep → template.aepx in order) can't return the old file.
	for _, n := range []string{"bundle.zip", "template.aep", "template.aepx"} {
		if n != destName {
			_ = h.minio.RemoveObject(ctx, h.templatesBucket, fmt.Sprintf("templates/%s/%s", pid, n), minio.RemoveObjectOptions{})
		}
	}

	src := minio.CopySrcOptions{Bucket: srcBucket, Object: srcKey}
	dst := minio.CopyDestOptions{Bucket: h.templatesBucket, Object: destKey}
	if _, err := h.minio.CopyObject(ctx, dst, src); err != nil {
		c.JSON(http.StatusBadGateway, models.APIError{Code: "copy_failed", Message: err.Error()})
		return
	}

	info, err := h.minio.StatObject(ctx, h.templatesBucket, destKey, minio.StatObjectOptions{})
	if err != nil {
		c.JSON(http.StatusBadGateway, models.APIError{Code: "stat_failed", Message: err.Error()})
		return
	}

	c.JSON(http.StatusOK, setBundleResponse{
		Bucket:   h.templatesBucket,
		Key:      destKey,
		MD5:      strings.Trim(info.ETag, "\""),
		Size:     info.Size,
		IsBundle: isBundle,
	})
}

// parseObjectURL extracts the bucket and object key from a path-style storage URL
// such as http://host:9000/<bucket>/<key...>. Query/fragment are ignored.
func parseObjectURL(raw string) (bucket, key string, err error) {
	u, perr := url.Parse(strings.TrimSpace(raw))
	if perr != nil {
		return "", "", fmt.Errorf("parse url: %w", perr)
	}
	p := strings.TrimPrefix(u.Path, "/")
	if p == "" {
		return "", "", fmt.Errorf("url has no path: %q", raw)
	}
	parts := strings.SplitN(p, "/", 2)
	if len(parts) != 2 || parts[0] == "" || parts[1] == "" {
		return "", "", fmt.Errorf("cannot derive bucket/key from %q", raw)
	}
	k, uerr := url.PathUnescape(parts[1])
	if uerr != nil {
		k = parts[1]
	}
	return parts[0], k, nil
}