package handlers

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

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

type InternalHandler struct {
	store           *db.Store
	notifier        *notifier.Client // may be nil — notifications are best-effort
	minio           *minio.Client
	templatesBucket string // bucket that holds .aep project files
	exportsBucket   string // bucket that receives rendered MP4 outputs
}

func NewInternalHandler(store *db.Store, n *notifier.Client, mc *minio.Client, templatesBucket, exportsBucket string) *InternalHandler {
	return &InternalHandler{
		store:           store,
		notifier:        n,
		minio:           mc,
		templatesBucket: templatesBucket,
		exportsBucket:   exportsBucket,
	}
}

// completeRequest is the body for POST .../complete
type completeRequest struct {
	ExportID *uuid.UUID `json:"export_id"`
}

// failRequest is the body for POST .../fail
type failRequest struct {
	Reason string `json:"reason" binding:"required"`
	AtStep string `json:"at_step"` // optional: which render step failed
}

// POST /v1/internal/render/jobs/:job_id/complete
func (h *InternalHandler) Complete(c *gin.Context) {
	jobID, err := uuid.Parse(c.Param("job_id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid job_id"})
		return
	}
	var req completeRequest
	_ = c.ShouldBindJSON(&req) // export_id is optional

	job, err := h.store.CompleteJob(c.Request.Context(), jobID, req.ExportID)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}

	// Fire notification if the user requested it (tell_me_when_done)
	if h.notifier != nil && job.TellMeWhenDone {
		jobName := ""
		if job.Name != nil {
			jobName = *job.Name
		} else if job.Title != nil {
			jobName = *job.Title
		}
		h.notifier.NotifyRenderDone(c.Request.Context(),
			job.UserID, job.TenantID, job.ID, job.ExportID, jobName)
	}

	c.JSON(http.StatusOK, gin.H{"status": "done", "job_id": job.ID})
}

// POST /v1/internal/render/jobs/:job_id/fail
func (h *InternalHandler) Fail(c *gin.Context) {
	jobID, err := uuid.Parse(c.Param("job_id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid job_id"})
		return
	}
	var req failRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: err.Error()})
		return
	}
	atStep := req.AtStep
	if atStep == "" {
		atStep = "Rendering"
	}

	job, err := h.store.FailJob(c.Request.Context(), jobID, req.Reason, atStep)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}

	// Notify user of failure
	if h.notifier != nil {
		jobName := ""
		if job.Name != nil {
			jobName = *job.Name
		} else if job.Title != nil {
			jobName = *job.Title
		}
		h.notifier.NotifyRenderFailed(c.Request.Context(),
			job.UserID, job.TenantID, job.ID, jobName, req.Reason)
	}

	c.JSON(http.StatusOK, gin.H{"status": "failed", "job_id": job.ID})
}

// POST /v1/internal/nodes/:node_id/heartbeat
func (h *InternalHandler) Heartbeat(c *gin.Context) {
	nodeID, err := uuid.Parse(c.Param("node_id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid node_id"})
		return
	}
	var req models.NodeHeartbeatRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: err.Error()})
		return
	}
	req.NodeID = nodeID
	if err := h.store.UpdateNodeHeartbeat(c.Request.Context(), nodeID, &req); err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"next_heartbeat_in_sec": 5,
		"pending_commands":      []any{},
	})
}

// POST /v1/internal/nodes/:node_id/online
func (h *InternalHandler) Online(c *gin.Context) {
	nodeID, err := uuid.Parse(c.Param("node_id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid node_id"})
		return
	}
	var req models.NodeOnlineRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: err.Error()})
		return
	}
	if err := h.store.UpdateNodeOnline(c.Request.Context(), nodeID, &req); err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}
	c.Status(http.StatusOK)
}

// POST /v1/internal/render/jobs/:job_id/frames
func (h *InternalHandler) FrameProgress(c *gin.Context) {
	jobID, err := uuid.Parse(c.Param("job_id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid job_id"})
		return
	}
	var req models.FrameProgressRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: err.Error()})
		return
	}
	if err := h.store.UpdateFrameProgress(c.Request.Context(), jobID, &req); err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}
	c.Status(http.StatusNoContent)
}

// POST /v1/internal/render/jobs/:job_id/crash
func (h *InternalHandler) Crash(c *gin.Context) {
	jobID, err := uuid.Parse(c.Param("job_id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid job_id"})
		return
	}
	var req models.CrashReportRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: err.Error()})
		return
	}
	if err := h.store.InsertCrash(c.Request.Context(), req.NodeID, jobID, &req); err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"action_recommended":     "ResetAndRestart",
		"reassigned_to_node_id": nil,
	})
}

// POST /v1/internal/render/jobs/:job_id/replica-ready
func (h *InternalHandler) ReplicaReady(c *gin.Context) {
	_, err := uuid.Parse(c.Param("job_id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid job_id"})
		return
	}
	var req models.ReplicaReadyRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: err.Error()})
		return
	}
	// In production: update job step to TemplateCache → JsxGen, signal next pipeline phase
	c.Status(http.StatusNoContent)
}

// POST /v1/internal/render/jobs/:job_id/preview
// Node agent pushes a base64-encoded frame image so the frontend can show
// a live preview while the job is rendering.
func (h *InternalHandler) Preview(c *gin.Context) {
	jobID, err := uuid.Parse(c.Param("job_id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid job_id"})
		return
	}
	var req struct {
		ImageB64 string `json:"image_b64" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: err.Error()})
		return
	}
	if err := h.store.UpdateJobPreview(c.Request.Context(), jobID, req.ImageB64); err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}
	c.Status(http.StatusNoContent)
}

// POST /v1/internal/render/jobs/:job_id/progress
// Node agent pushes the render percentage so the UI shows a moving bar + ETA.
func (h *InternalHandler) RenderProgress(c *gin.Context) {
	jobID, err := uuid.Parse(c.Param("job_id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid job_id"})
		return
	}
	var req struct {
		Progress int `json:"progress"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: err.Error()})
		return
	}
	if err := h.store.UpdateJobProgress(c.Request.Context(), jobID, req.Progress); err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}
	c.Status(http.StatusNoContent)
}

// POST /v1/internal/render/jobs/claim
// Node agent calls this to atomically claim the next queued job.
// Returns 204 when there is nothing queued (agent should back off and retry).
func (h *InternalHandler) Claim(c *gin.Context) {
	var req models.ClaimJobRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: err.Error()})
		return
	}

	job, err := h.store.ClaimJob(c.Request.Context(), req.NodeID, req.Region)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}
	if job == nil {
		c.Status(http.StatusNoContent) // nothing queued
		return
	}

	// Resolve the canonical template object. Each template is stored once, per
	// project id, at templates/{original_project_id}/<name> in the templates bucket
	// and reused by every render of that template. A .zip is a full AE project
	// bundle (.aep + footage/fonts) the node must extract before rendering.
	// Errors are non-fatal — the node agent falls back to mock render when URL is empty.
	// Resolve the render engine + composition for this template. Remotion
	// templates are code-based and need no .aep download.
	rcfg, _ := h.store.GetTemplateRenderConfig(c.Request.Context(), job.OriginalProjectID)

	aepURL := ""
	isBundle := false
	bundleMD5 := ""
	if rcfg.Engine != "Remotion" && h.minio != nil {
		candidates := []struct {
			name   string
			bundle bool
		}{
			{"bundle.zip", true},
			{"template.aep", false},
			{"template.aepx", false},
		}
		for _, cand := range candidates {
			objectKey := fmt.Sprintf("templates/%s/%s", job.OriginalProjectID, cand.name)
			info, serr := h.minio.StatObject(context.Background(), h.templatesBucket, objectKey, minio.StatObjectOptions{})
			if serr != nil {
				continue // not this format
			}
			purl, perr := h.minio.PresignedGetObject(context.Background(), h.templatesBucket, objectKey, 2*time.Hour, nil)
			if perr != nil {
				continue
			}
			aepURL = purl.String()
			isBundle = cand.bundle
			bundleMD5 = strings.Trim(info.ETag, "\"")
			break
		}
	}

	// Composition to render: AE comp (-comp) or the Remotion composition id.
	// Non-fatal: empty → AE node uses the render queue.
	compName := rcfg.CompName

	// User's edited input values → the node writes them into the AE project before
	// rendering, or passes them as Remotion --props. Non-fatal: empty → template defaults.
	// FlexStory (scene engine) needs the structured per-scene shape (grouped by scene
	// + per-scene duration + theme colours); everything else uses the flat union.
	var bindings []models.RenderBinding
	if rcfg.Engine == "Remotion" && strings.HasPrefix(rcfg.CompName, "FlexStory") {
		if flex, ferr := h.store.GetFlexStoryProps(c.Request.Context(), job.SavedProjectID); ferr == nil && flex != "" {
			bindings = []models.RenderBinding{{Key: "__flexprops__", Type: "json", Value: flex}}
		}
	} else {
		bindings, _ = h.store.GetRenderBindings(c.Request.Context(), job.SavedProjectID)
	}

	c.JSON(http.StatusOK, models.ClaimedJob{
		JobID:          job.ID,
		SavedProjectID: job.SavedProjectID,
		Quality:        job.Quality,
		Resolution:     job.Resolution,
		FrameRate:      job.FrameRate,
		HasMusic:       job.HasMusic,
		HasVoiceover:   job.HasVoiceover,
		Engine:         rcfg.Engine,
		AEPDownloadURL: aepURL,
		IsBundle:       isBundle,
		BundleMD5:      bundleMD5,
		CompName:       compName,
		Bindings:       bindings,
	})
}

// POST /v1/internal/render/jobs/:job_id/output-upload-url
// Node agent calls this after rendering to get a presigned MinIO PUT URL.
// Creates an Export record in the DB and returns the export_id + upload URL.
func (h *InternalHandler) OutputUploadURL(c *gin.Context) {
	jobID, err := uuid.Parse(c.Param("job_id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid job_id"})
		return
	}

	export, err := h.store.CreateExportForJob(c.Request.Context(), jobID)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}

	expiry := 2 * time.Hour
	purl, err := h.minio.PresignedPutObject(
		context.Background(), h.exportsBucket, export.Path, expiry,
	)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{
			Code:    "presign_error",
			Message: "could not generate upload URL",
		})
		return
	}

	c.JSON(http.StatusOK, models.OutputUploadURLResponse{
		ExportID:  export.ID,
		UploadURL: purl.String(),
		ObjectKey: export.Path,
		ExpiresAt: time.Now().Add(expiry),
	})
}

// POST /v1/internal/nodes/:node_id/cache-update
func (h *InternalHandler) CacheUpdate(c *gin.Context) {
	nodeID, err := uuid.Parse(c.Param("node_id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid node_id"})
		return
	}
	var req models.CacheUpdateRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: err.Error()})
		return
	}
	if err := h.store.UpdateNodeCache(c.Request.Context(), nodeID, &req); err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}
	c.Status(http.StatusNoContent)
}